In reply to dannyp84 :
Mini is full bridge with 1" semi pp combo. The motor has been balance by mazdatrix.but your right it need to get rev high to take advantage of the porting
In reply to dannyp84 :
Mini is full bridge with 1" semi pp combo. The motor has been balance by mazdatrix.but your right it need to get rev high to take advantage of the porting
In reply to dannyp84 :
Sorry, I'm not dead! A lot has happened with the car and I really do need to update this. I will say that yes, it is back together and I was able to make it out to the last event at Summit Point in November. I ended up running into some issues that necessitated the engine coming back out but now it's back together again and it looks like the season opener at VIR is a go.
The "you need RPM to make power" is an oversimplification. Simply put, you need air and fuel to make power. The more air+fuel you can get in the engine the more power it'll make. The problem is mass flow is a function of area and velocity and the engine can only flow so much at any given speed. What's ideal at one speed isn't ideal at another. Massive ports CAN flow a lot of air but the engine can only use so much so at lower engine speeds the intake velocity is really low. This is the low-end power loss that everyone complains about. Conversely, small ports have great velocity at lower speeds but can't flow enough at higher speeds. This is where engines feel like they run out of steam at high RPM. The trick is balancing port size to what your needs are. This is why factory engines get all fancy with variable intake geometry and timing. My engine makes over 230 hp to the wheels at a reasonable 8500 RPM. My torque curve is also nearly flat from 5500-8500 RPM. I'm definitely giving up power at both ends but my goal was to keep things relatively simple and I think I've come away with a good compromise.
We need videos with braps, revs and burnouts
Ok, time to try to catch up on this. Looks like my last update was from around mid-June last year. A lot of the delay was waiting on various parts to come in. Mazda Motorsports is incredibly fast but I needed to get my hands on a few aftermarket parts as well. One of the biggest hold ups was the special springs needed for my aftermarket ceramic apex seals. Combine this with the usual family Summetime stuff and progress was slow. I ended up blowing right through both the June Summit Point event. Around the middle of July I finally started making progress. Step one is assemble the rotors. I don't think I ever posted the result before but lightened and scalloped rotors look pretty cool.
All new seals (except apex) and springs. Bearings were reused throughout. I'll spare the majority of the engine rebuild pictures since most people know what that looks like by now. I'll just share a few. Stacking the sandwich:
What isn't shown is I upgraded to some hollow, single-piece engine dowels. From the Factory Mazda uses four in two locations to keep everything centered. You can see two of these in the picture above. Single-piece dowels run all the way front-to-back and are supposed to be better at keeping everything aligned and straight. However, because they're long, they get in the way so I use the shorter factory ones during assembly. They're threaded internally so it's easy to screw in a long bolt and pull them out once the center iron is installed. Then I just drop in the single-piece ones without moving anything. All buttoned up:
At this point it's still mid/late July and things were looking good for VIR in August. I decided to do something I'd never done before and pressure test the coolant passages. Some of my coolant seal slots look a little questionable but they've never given me problems in the past. Unfortunately, this time around I wasn't so lucky. I pressurized the system to 20 psi and within 30 minutes it was down to 15 psi. I confirmed this multiple times over so I must have messed up somewhere. Thus began the tedius process of undoing everything I had just completed over the past two days and cleaning everything up (I made a silly decision to fill the block with coolant to pressure test it).
Overall it took me about two weeks to completely disassemble the block, clean all the parts and put everything back together. Since it was never started I reused all the springs and seals. I went heavier on the hylomar (probably excessively so) the second time around and just pressurized the block with air. Fortunately, this time it held 20 psi for over 24 hrs!
Time to finish up the block and get it in the car. Another item I splurged on is a fancy baffled, dump sump oil pan. I never really had any issues with oil starvation with the factory pan and Racing Beat baffle but figured something fancier with more capacity wouldn't hurt. Pineapple Racing used to make these and I had one on order but I just barely missed out on their last(!) run. Fortunately, another supplier stepped in to fill the gap:
Front/back and side/side baffling with windows. I did have to modify the pickup tube and dipstick cutout but my understanding is I'm one of the first to run this pan so call it beta testing. Flange thickness is also a beefy 3/8" so no more Banzai brace. Unfortunately, this meant I had to ditch my AWR engine mounts and go back to the stock ones. Although it's not stated as being necessary I had the passenger side mount machined down to keep the engine in the same position. All buttoned up and ready to go in:
Note to self: don't install the front pulley until the water pump is installed. They interfere and I think I've rediscovered this fact three times now.
From here out it's pretty straightforward. Getting the engine back in with the transmission in the car is a bit of a pain and from here on out I've decided to just remove/install both together. Ready to fire:
A family trip in early August meant I had to wait a week or so but it fired up like it had never been out. I guess that's the beauty of reusing apex seals? I have several videos of the car idling and revving in neutral at this point but it doesn't look like I can upload them unless they're hosted on YouTube or similar.
Now it's mid August and I have the car running but it's <2 weeks until VIR. I could have risked it but thought better and backed out. I decided to take ~2 months to make sure everything was in order and shaken down before the last event of the year at NASA MA's Fall Finale at Summit Point. I was able to put around 800 miles on the car during this time and I also finally did something I've been waiting to do for 5 years - finally get the car tuned by a professional. Sure, I've had "experts" tweak things here and there and even done some WOT tuning on dyno's but I never had someone just sit with the car for hours and get everything sorted out. That changed in October when a well-known remote tuner happened to be doing work at a shop about 3 hours from me. We worked things out, made a plan and I took a day off work to bring the car to him. Overall we spent probably 4 hours on a dyno and back roads getting everything from cold start and transient throttle settings dialed in. In the end this is what it made:
Lots to digest here. Yes, it's showing less power and torque than before. It put down 240/160 in 2019 after I switched up the intake and 250/170 in 2021 after I finished the air box and had some tuning done. However, I'm not that concerned for a couple reasons. First, these are all different dyno's and I know they all give different results. Second, we deliberately left this tune conservative. I'm okay with losing some hp if it means I can get more life out of the engine. There's definitely some room to advance timing and lean out the air-fuel mixture but I really don't want to be rebuilding engines every few years. What's not shown here is just how much better than car runs. Cold starts, hot starts, transient throttle - everything is massively improved.
Nowhere was this more apparent than on the track. I signed up and made it to Summit Point for the last event of the year.
The weather was cold but after a bit of a wet start on Saturday it turned out to be a pretty good weekend. The car felt great on track. No more hesitation, bucking, etc. Just smooth acceleration to redline. In fact, I hit my highest ever on-track speeds. Part of this is becoming a better driver but also because I can get on the throttle more quickly without worrying about upsetting the car mid-corner. What made this event even better was I was finally able to include my oldest. He's still too small to go out during hot sessions but we made the best with parade laps.
The only letdown is he said he wants a BMW race car when he's older (he was enamored with the car in the background three photos up).
The reason the weekend was just "pretty good" is because I unfortunately ran into some issues. First was a random no start after attempting to fill up immediately after a session. I pulled into the paddock, grabbed some stuff and headed over to the pumps. When I got there I failed to remember I gave my son my wallet so he could get lunch. I went to start the car and it fired off but immediately died. Further attempts resulted only in cranking. I fought this for a few minutes before giving up and, with the help of others, pushed it back to my spot in the paddock. I poked around and found nothing immediately obvious. I resigned myself to the fact my day might be over and decided to get some lunch. Right as the next session was about to begin I decided to try one more time. Of course it fired right up. I quickly drove to the pumps and filled up, threw on my helmet and was able to get out there a lap or two behind the rest of the group. This condition never happened again. I'm still not sure what happened but looking through ECU logs it looked like I was losing fuel pressure. Like the pump was turning off shortly after the car started. I don't know if it overheated (fuel level was pretty low) or if my electrical system just couldn't handle the startup load (fan was also running). Whatever the reason, I made sure not to let the fuel level drop quite so low and I let the car cool down to the point where the fan turned off before restarting.
The next issue turned out to be more serious, though fortunately it occurred at the end of the event. After my third session on Sunday I found quite a lot of oil under the air box. I always see a little but this was excessive. Like catch can was full and oil was shooting right into the intake (closed PCV system). I figured it was because I was driving harder than I usually do and hadn't drained the catch can after the second session like I usually do. I cleaned up the mess, drained the catch can and went out for the last session of the event. The session was uneventful and I put down my fastest lap times of the event. No warning lights or anything to suggest anything was wrong other than slightly lower-than-normal oil pressure near the end. I get back to the paddock and again find oil all over the intake and the catch can full. Well crap, something isn't right...
Leaving Summit Point the car felt alright. It had started and driven onto the trailer with no issues. After the three-hour drive home it was a little different. It was hard to start and even afterward it was idling strangely. Low idle speed and running pretty rich. Pulled the plugs and they looked good but when I finally connected the laptop I immediately saw something. My intake air temperature was reading like 14F. I've seen this before. My car seems to eat IAT sensors. Now looking back I think it's because oil from my PCV system gets on the sensor and causes it to freak out. This time, however, it was different:
That'll do it. Fortunately, an easy fix. Also good news is that dousing the IAT sensor with some electronics cleaner seemed to reverse the effects of it being soaked in oil. Then there's the oil in the intake issue. The best way I can describe this is imagine massive blow by. Once I fixed the IAT sensor harness I started the car and removed the oil cap. Any amount of revving the engine produced a spit of oil out the filler tube (again, I have a video but it seems silly to upload a 18 sec video to YouTube so I can share it here). Crap, how could I be generating that much crank case pressure?
After waffling back and forth I finally decided the engine was going to have to come out again. First step - drain the oil. What a waste of perfectly good Redline 40WT. What's that attached to the magnetic drain plug?
At first I thought it was the bottom of some M6 bolt that shared off but after some cleaning:
Hmm, some kind of set screw. There are only a few areas set screws are used in Mazda's rotary: stationary gear bearing retainers and the oil pump. I did some internet searching and whaddayouknow, there have been a handful of documented cased where the oil pump set screw has backed out. So screw source identified and the engine has to come out and be partially disassembled to address. But what I didn't know is if this somehow explain the crank case pressure I was seeing. To make sure I didn't have any potential seal failures I did a quick and dirty compression test. Approximately 100 psi across all three faces of each rotor. Granted, this was with a piston compression tester (Schraeder valve removed), and with the engine cold. That said, my cranking speed is just a hair over 200 RPM. Correcting for engine speed puts my compression quite a bit higher so hopefully that offsets the reduction seen when the engine is warm.
Two weeks go by. I've slowly pulled off the engine accessories, cleaned them and now I have the engine (and transmission) removed. Time to start digging. Off comes the front cover and front stack assembly and sure enough, no set screw in the oil pump. After being removed and cleaned up:
So what does that set screw do? Well this is a two-stage oil pump and that screw keeps what Mazda calls the "middle plate" from spinning inside the housing. Here's the rotor assembly:
The screw fits in that little keyway. What happens when it comes out? I'm not entirely sure. You'd think the middle plate would start spinning but there's not a lot of evidence of that happening.
Even if it does spin then what? Maybe that explains my slightly lower than normal oil pressure? As I mentioned I was watching pressure intently during that last session and never did it drop below about 80 psi. Mazda threshold is 64-78 psi above 3000 RPM and with my upgraded setup I usually saw 90+. Can oil just start spraying out of the hole? Maybe that's what is was causing all the crank case pressure?
So I've got the engine out and partially disassembled but I really don't want to have to take this thing apart again. Since compression looked okay and oil pressure never really dropped too low I was advised to pull the stationary gears and check out the bearings. Front:
Rear:
Not perfect, but no worse than I remember them being a couple months ago. Certainly nothing I can feel with a fingernail. After some thought I decide I'm going to run with it. New oil pump (just in case) and new seals to replace any I'd exposed.
It's early December and the season's over so I'm in no hurry. I order the parts from Mazda Motorsports and use the end-of-year time off to periodically work on the car between holiday parties and vacation. I really wanted to have it running before Christmas but this is as far as I got. Last picture before the holidays:
I will repeat it here. It's so much easier to remove and install the engine and transmission as a pair. I also discovered I'd boogered the pilot bearing seal when I installed the engine back in August. No real risk of doing that with both out of the car. I resumed my effort about two weeks later and on January 7 I started the car again. Just like before it fired off after about a second. I let it fully warm up and bleed the coolant system. Once I'm confident there aren't any leaks and all the excess oil in the vacuum lines has been sucked out and burned off I repeat my test from the previous month. Removed the oil cap and gave it a few good revs and boom, no oil spit. Okay, maybe one drop or two but nothing's perfect. Good enough for me. I'm still not sure how that set screw missing caused all this but I'm glad it's fixed and the engine seems alright. We're at present day and I've only driven the car once since then. It's generally been too cold and miserable (40s and rain) but everything seems in order.
As for future plans I still need to install my upgrade wideband kit and IC7 display I got last year. I also want to redo my catch can and PCV setup. Mainly give myself more capacity and the ability to catch oil going to the air box. I also still have a pipe dream of making some kind of splitter/undertray. I definitely need something in the front as the car starts to feel light over 100 mph. As far as track plans go I've already registered for VIR in March and an event at Pitt Race in July. I'm going to scale back this year and my goal is to hit every planned track just once: VIR, Dominion, Pitt Race, Summit Point Shenandoah, Summit Point Jefferson and finally Summit Point Main.
It's been a few weeks so it's time to update again. We left off in early January where I'd gotten the car back together and driving. I took a small break at the end of the month. It's become a bit of a tradition for my family to take a trip down to FL in late January every three years. We catch the Rolex 24 Hours at Daytona and then spend the next week at the various Disney parks. Been doing this every three years since 2014 but now we're thinking of doing it more frequently. The kids keep getting older so we figure we'll get as many of these trips in as we can before it's no longer "cool..."
Anyway, with January gone and the first event scheduled for mid-March I needed to get to work. I drove the car a few times and convinced myself everything was in order so the only reasonable thing to do was to tear it apart again. I've been sitting on a Haltech IC7 display and dual channel CAN wideband setup for about a year so it was time to get those installed. Lots of crawling around and contorting myself under the dash reminded me I'm not as young as I once was. Part of the issue was how integrated the old setup was with the stock wiring harness. Not much to photograph but I was happy to be greeted with this when plugged in and powered up:
This is with zero setup/calibration. I confirmed the integrated turn signal and high beam indicators work as well as the dimming function. No more separate lights and this display will even show a CEL if one of the various warning conditions I set in the ECU are triggered. After playing with Haltech's ICC software for a bit I was able to get something familiar:
Yeah, it's not very original but I wanted something I could use to confirm everything was working properly. So far I like the new setup. It's more user-friendly and has far more capability than the old setup. My only complaint is there is no filter to the datastream like the IQ3 had. This allowed me to smooth out the data delivery to display more constant numbers. Definitely useful for things like speed and fuel level. I imagine this isn't really an issue with the analog gauge displays. The only issue I've encountered is my ancient tuning laptop can't run the ICC software so I have to steal SWMBO's fancy Surface laptop whenever I want to make changes.
I got the dual channel CAN wideband setup installed at the same time. Not really anything to show there. I had a small freakout when I started to see wildly varying AFRs between the front and rear rotors. After lots of searching and troubleshooting I finally did the smart thing and connected the laptop to the ECU to see what was going on. Found out immediately the ECU was adding fuel to the front and pulling it from the rear, which is exactly the opposite it should have been. That made me realize I had made some silly compromises with the previous setup (wideband 2 was front and 1 was rear, etc.). Changed the O2 control settings (front rotor trim is controlled by WBO2 1, etc.) and all is good. The car feels the same as it did last November although oil pressure seems slightly higher. Might just be the colder temperatures...
Another item I wanted to address was the fuel pump wiring. I had 12 AWG wire from the pump all the way to a DTP connector near the ECU. This connector ran to the fuse/relay box, which is fed by a 8 AWG from the battery. The issue is the wiring between the DTP connector and fuse box. My harness builder utilized the off-the-shelf Haltech loom as a starting point and he kept what I think was 16 AWG wire for fuel pump power. The run is probably <2 ft but I never did like having this for a pump that can pull upwards of 15A at 5 bar fuel pressure. My solution was to bypall the DTP connector and run the 12 AWG wire directly to the relay output in the fuse box. Simple enough stuff but I was met with a surprise:
This is the fuse side of the small jumper wire between the fuel pump fuse and relay. I was clued into this by the fuse itself, which was warped and partially melted, but not blown. It's pretty clear this got hot but I don't know why. It looks to be at least 12 AWG wire (maybe 10) and the terminal is crimped AND soldered. Best guess I have is the crimp cracked the terminal at manufacture and someone soldered it instead of replacing it. The solder oxidized and increased resistance, which led to more heat and the crispy-ness shown above. The relay side of the wire looked fine. Maybe this is why I was seeing a small drop in fuel pressure at WOT (would drop a couple psi at higher RPM)? I replaced this jumper with a fresh 12 AWG wire and now the fuel pump is run directly to the other side of the relay so wire is 12 AWG or greater all the way from the battery.
I've also started working on small things that have bothered me for years. Simple things to clean up the engine bay like correcting the wiring harness. It's always been a little long in places and I've had some extraneous connectors and sub-harnesses in case I decided to change setups over the years. At this point I think the setup is pretty well finalized so I don't think I need all the break-out connectors. It's a minor change but I think it cleans up the wiring on top of the engine:
There's still a couple break-outs near the rear of the engine. One is for the MAP sensor and the other is just a aux pass through for anything I might need (currently used for fuel pressure). I think I can eliminate the MAP break-out as well but it isn't a priority since it isn't quite as upfront as the others were. The next things will be making a shorter fuel line from the FPR to the fuel rail to eliminate the kink. It was straight at one point but I changed engine mounts, which I guess shifted the location of the engine slightly. I also have some fancy aluminum vacuum fittings to replace the generic hardware store brass ones.
I also want to clean up/rework the EVAP/PCV and brake booster hoses. The factory had hard lines that ran along the firewall. I ditched the factory vacuum booster hard line because the 929 booster has the vacuum port on the opposite side. In hindsight, it would have been better to just cut the line shorter. Without the booster hard line there's nothing for the EVAP hard line to clamp onto so those both got replaced with generic vacuum/fuel hose. I managed to find a used set of hard lines since I tossed mine years ago and now I'm working on a setup that will incorporate those along with a fancy Radium Engineering catch can. The trick is getting the catch can to function on both the intake and vacuum sides.
Speaking of brake boosters I've finally gotten my hands on a dual diaphragm unit from the 89-91 turbo RX7s. These are unique in that they have 7"/8" diaphragms and use the same master cylinder style as the 929 I have. A little background here: all 86-88 and 89-91 N/A RX7s with the 4 piston front calipers and vented rear discs use the same 9" vacuum booster and 7/8" master cylinder. 89-91 turbo RX7s were changed to the 7"/8" booster and a 15/16" master cylinder. FD RX7s got 8"/8" boosters and 15/16" master cylinders and the last RWD 929s got 8"/9" boosters and 1" master cylinders. When building my car I swapped in the 929 setup. While I like the pedal travel distance, the more I've tracked the car the more I feel the brakes are overboosted. It's very easy to lock up the brakes and the pedal is pretty soft, which can make heel-toe downshifting interesting. Since the 89-91 turbo RX7, FD and 929 all use the same master cylinder designs it makes sense that I can go with the smaller booster for less assist but maintaining the same pedal travel. I put out a WTB post on Facebook and someone answered my call. The price was right so I pulled the trigger. Unfortunately, the part I received isn't in that great of shape. It's definitely suffered a master cylinder leak or two in its past. After some significant cleaning and wiring wheeling this is how it looks now:
The good news is all the surface rust and scale came off and the remaining pitting can easily be covered up with some body filler and some paint. The bad news is there is a small leak somewhere. With a fresh, spare master cylinder installed (required for sealing) and 20 in. Hg applied it'll loose half that in about 5 minutes or about 2 in. Hg per minute. For comparison the 929 booster on the car doesn't lose any appreciable vacuum after 5 minutes. I can hear the leak but can't pinpoint the source. I don't think it's coming from the master cylinder interface but the sound is definitely louder near the bottom. So now I'm torn. On one hand, it's a pretty small leak that I doubt would cause any noticeable engine issues and I would still get one or two good braking actions if the engine were to die while in motion. On the other, a leak never really fixes itself and there's no guarantee it won't get worse. I WANT to get it fixed but apparently there are no rebuild kits or core replacement services for this booster. I've reached out to a couple places that rebuild them but so far the best response I've got is send us some pictures and we'll get back to you.
That's pretty much up to date. Other than the usual pre-season maintenance there isn't really anything I HAVE to do before VIR in March.
How hard was it to find the 929 parts? I've been looking for an HC 929 in decent shape and it's pretty much a lost cause. I like the feel of my FC brakes, the convertibles share the 4 piston calipers with the Turbo II from what I've been told, definitely better braking power and pedal reel than the FB. With the pedal too soft for heel-toes, were you finding that you'd have to go too deep into the brake pedal to be lined up well to get your foot on the gas? The civic we race in champ car has the opposite issue, where to reach the accelerator it's hard not to lock up the brakes.
In reply to dannyp84 :
I got the 929 booster in (checks time stamp on picture) 2013. It's been 10 years(!) so they're probably harder to find now. I used car-part.com, found some pick-and-pull yards within an hour and kept going until I found what I needed. The booster is the tricky part. I think you can still get rebuilt master cylinders. I have one in storage because I found it on Amazon for like $35. I keep reading about people using master cylinder and booster combinations from other cars even outside Mazda. N/A cars with the "sport" brakes have a 7/8" master cylinders and s 9" single diaphragm booster. That's your baseline. Increase master cylinder size for less pedal travel but more effort. Increase brake booster size and/or number of diaphragms for more assist.
Full disclosure, I don't heel-toe properly. I cheat and use one side of my foot for brake and kinda roll onto the other side to blip the throttle. Some aftermarket, wider pedal covers make this really easy. This is part of why I wanted the 929 master cylinder. With the stock setup hard braking would put the brake pedal below the throttle pedal. This made blipping the throttle difficult because of the limited range of motion using the sides of my foot. The larger 929 master cylinder reduced pedal travel and alleviated this issue. However, as I'm getting better at driving and braking later/harder I'm running into the issue you mentioned with your Civic. It's easy to lock the brakes if I'm not careful. This is why I wanted the smaller booster. Same pedal travel but will have slightly less assist, which will hopefully reduce the chances of locking the brakes. I should probably just learn to heel-toe properly...
In reply to infernosg :
I use essentially the same method for heel toe that you do, and I'm not particularly great at it, though it's much easier in either RX7 than in the Civic. You're making me want to pull the FC out of storage early to go for a spin, I really love the feel of that car. I've got some hopefully lighter than stock wheels on ice for it, and I'd like to freshen up the suspension and lower the car a bit, though from what I've read that's a can of worms regarding the rear trailing arm design and getting your alignment correct.
In reply to dannyp84 :
Yeah, as soon as you start lowering the rear it immediately starts gaining negative camber and toe in. As long as you aren't slamming the car it is easily correctable. I like the individual camber adjusters for each side rather than using an adjustable vertical link. I've got the AWR units but you can get shorter, fixed length ones from Ronin Speedworks. Just note you may have to use different lengths for each side to have even camber.
Not much new the past week or so. Spent way too much on four of these:
I've also continued to waste my time on silly things like cleaning up the engine bay. I eliminated another extraneous connector and made a slightly shorter fuel line from the rail to the FPR. For some reason when I changed engine mounts a while back it moved the engine and put a bend in this line. It had no impact on the operation of the car but it always bothered me how it looks. Everything is nice and straight now. I've also started revamping my EVAP/PCV system. A while back I picked up a Radium Engineering catch can. It's got a larger capacity and is more versatile than my previous catch can. This is how the engine bay currently sits:
I'm still working on the PCV system. Right now, the setup goes air box -> port at bottom of oil filler neck -> port at top of oil fillter neck -> catch can inlet -> catch can outlet -> PCV valve (from FD RX7) -> intake manifold. This works really well at keep moisture out of the oil filler neck since air is constantly being circulated through it. It also does a good job collecting oil vapor as the old catch can would be filled after 4 sessions or so. The issue I'm having is I get a decent amount of oil in the air box. My best guess is at WOT there is little/no vacuum in the intake manifold but probably a slight vacuum in the air box so oil vapor is going backward through the first line in the system. My current setup also has a separate circuit for the EVAP side, which uses a FD purge solenoid controlled by the ECU. The line tees into the PCV line right before it hits the intake manifold. Again, this works great at keeping my garage from smelling like gasoline on hotter days but it's still a somewhat complicated system.
My solution integrates the EVAP and PCV lines like they were on the FC stock. The air path would be charcoal cannister -> bottom port on oil filler neck -> upper port on oil filler neck -> catch can inlet -> catch can outlet -> PCV valve -> intake manifold. This eliminates the fresh air source at the airbox because the charcoal cannister has a port at the bottom that serves this purpose. I'm hoping this will reduce the oil build up I get in the air box. My only concerns with this setup are: (1) I'm now at the mercy of the PCV valve when it comes to regulating gas vapor into the engine and (2) without a vacuum source at the air box will I run into issues with crank case ventilation at WOT? For (1) I'm hoping at worst I may need to tweak the fuel table in the ECU slightly. For (2) I'm significantly increasing the size of the line from the oil filler to the catch can. The hope is this'll act like a vent-to-atmosphere setup at WOT while still functioning properly under vacuum.
No pictures. VIR is next weekend so panic mode had ensued. 90% of the to-do list is completed. Now I'm waiting for nicer weather so I can do a final shakedown drive and confirm alignment settings. So far the weather looks like it's going to cooperate. The forecast was originally calling for rain Saturday but now it's saying some light showers overnight but sun during the day. A little chilly with highs in the mid-50s but that's good driving weather.
I decided I'm going to save the emissions changes for after VIR. At this point I'm pretty set in what I'm going to do. The only question is whether everything gets routed back to the intake manifold via a PCV valve or just straight to the intake duct. Otherwise, I don't have many plans for the car this year other than drive it (and not break it). I still need to make a front splitter and I confirmed my spare brake booster can be repaired. It's more than I want to spend and I'm not sure if I want to be tearing into the brakes right now. I thought I had a lead on another one (can't have too many spares) but the seller has ghosted me so I guess that fell through.
infernosg said:No pictures. VIR is next weekend so panic mode had ensued. 90% of the to-do list is completed. Now I'm waiting for nicer weather so I can do a final shakedown drive and confirm alignment settings. So far the weather looks like it's going to cooperate. The forecast was originally calling for rain Saturday but now it's saying some light showers overnight but sun during the day. A little chilly with highs in the mid-50s but that's good driving weather.
I decided I'm going to save the emissions changes for after VIR. At this point I'm pretty set in what I'm going to do. The only question is whether everything gets routed back to the intake manifold via a PCV valve or just straight to the intake duct. Otherwise, I don't have many plans for the car this year other than drive it (and not break it). I still need to make a front splitter and I confirmed my spare brake booster can be repaired. It's more than I want to spend and I'm not sure if I want to be tearing into the brakes right now. I thought I had a lead on another one (can't have too many spares) but the seller has ghosted me so I guess that fell through.
Sooooo....hows that last 10% coming? -Your NASA instructor at VIR this weekend:)
No really I'm your instructor this weekend, the assignments just came out. Can't wait! I love this build! Lets goooooo
In reply to Box4VIR :
Haha, that's awesome! We're good. I'm 99% done and that last 1% is just giving the car a wash. Call me crazy but I like to give everything a quick hose down before track days.
I was re-skimming this thread to see if you went into particulars about your suspension setup. What components are you using and are you happy with them so far? I want to do adjustable coilovers on my S5 convertible, and if the internet is to be believed, I need a whole host of adjustable components at the rear suspension if I want the alignment corrected once lowered. I don't want to bring the nose of the car down all that much, but it looks like the rear will have to be lowered substantially just to level out a lot of the factory rake these cars have.
In reply to dannyp84 :
My suspension is all upgraded but nothing is modified beyond the OEM design, if you follow my meaning. Fortune Auto 510 coilovers (solid/spherical bushings, inverted front struts, etc.) are the heart of everything. Every other bushing has been replaced with something polyurethane (front control arm and sway bar bushings), something solid (rear DTSS delete, rear control arm upper bushings, rear control arm forward inner bushings aka "camber linkes" and rear subframe "vertical link") or spherical bearings (rear control arm forward outer bushings, front sway bar end links and outer tie rods). One day I'd like to replace everything with spherical/roller bearings to eliminate all possible binding.
I think these cars are raked for a reason. If you level the car it'll look like the front is pointed upward, or at least I think so. The suspension geometry quickly gets out of sorts when you start lowering them. In the front you get bad roll center and bump steer. There isn't any off the shelf roll center correction for the front. I've seen people make some custom ball joint extensions. There are "bump steer correction" kits. What's hard is finding some that also don't add steering angle for the drifty folks. In the rear you gain negative camber and toe on top of messing with roll center. Unless you really slam it down the OEM toe adjustment will be sufficient but you can buy adjustable trailing links if you want. Camber is trickier and there are two options: an adjustable subframe vertical link and/or adjustable/shorter camber links. The former tilts the entire rear subframe to change the location of the rear control arm forward points. I personally don't like this method because you're stressing the rear subframe bushings and you're limited to one adjustment for both sides. The stock camber links can be replaced by shorter aftermarket ones. This means camber correction is fixed (companies sell multiple lengths) but you can somewhat adjust each side separately by using different lengths, if needed. AWR used to and still occasionally does make adjustable camber links, which is what I run. They aren't as user-friendly but offer by far the most camber correction available. There's not much you can do in the rear for roll center, but it usually isn't a problem if you aren't slamming the car.
In reply to infernosg :
It seems like everyone does the DTSS delete, my bushings must still be in decent shape because I don't seem to mind it. My understanding is that on the aftermarket camber links, one is longer on purpose to make the camber even on both sides, is that correct ?
In reply to dannyp84 :
The original ones offered by a Japanese company (Super Now?) were different lengths side to side, yes. The two most popular ones now, Ronin Speedworks and Parts Shop Max, offer three different lengths. I know Ronin sells a "master kit" with two of each length so you can mix and match as needed. I wasn't able to get the camber or side-to-side matching for my liking with these kits, which is why I went with the AWR Racing setup. For a street car I'm sure they'd be fine but I use this car almost exclusively for track days so I like having everything adjustable.
In reply to infernosg :
I'm thinking the Ronin versions will be fine for my uses, but I'll lower the car first and measure how much adjustment is needed and go from there.
This needs an actual update. VIR was a couple weeks ago now. Overall it was a great, if not cold weekend. Saturday wasn't bad but the first run on Sunday was around 35F. I was cleared for Solo on Saturday and I managed to keep it on track all weekend. By the end of the weekend I ended up hitting my fastest ever on track speed, destroying my previous PB by over 6 seconds and was putting down consistent lap times. I'm still very, very slow but I think it's actually comforting to know there are so many possible areas for improvement. My ultimate goal is a sub 2:10 lap, which is still a ways away but I think the car is capable.
Now for the not so great. I'm continuing to struggle with brake bias with this car. It is VERY easy to lock up the rears. So much so that threshold braking is a challenge. I sacrifice a ton of speed at the end of straights to brake earlier and lighter and I'm giving up speed in the corners due to little/no trail braking. I don't remember it being this bad two years ago so either I'm pushing the car harder so it's noticeable or something isn't right. There are several options: less aggressive rear pads, adjustable proportioning valve, etc. However, first I want to take a closer look at the front calipers. Both rears have been rebuilt in the last 2 years but the fronts are going on 8. I know at least one piston is sticky but I've never noticed it dragging. I've got an extra set in the garage I plan on rebuilding once I get through the current round of stuff. I also still have that smaller vacuum booster...
Finally, the bad. I ran into the same issue I encountered at SP last November. There, I ran the entire event with no issues until the second-to-last session. After that I found oil all over the intake and a full catch can. I also saw some weird (but not low) oil pressures. Recall, I found a set screw in the oil pump had backed out. I fixed that over the Winter and all seemed good. At VIR I was religiously checking oil level and the catch can. Everything was great until the last run. I can't remember if I checked it after the previous session but I was again greated to a full catch can and oil all over the intake. It had been fine for the other 6/8 runs of the weekend. Assuming I lost another set screw I packed up and went home. Here's a departing shot from VIR:
The next day I immediately begin tearing into things after work. I drained the oil but found no set screw. Maybe the magnetic drain plug just didn't catch it. I then dropped the pan and still found nothing. I remembered I had a cheap endoscope so I poked that down the front cover and sure enough, the set screw was still in place:
Now I'm confused. Last year I had assumed oil was spraying out of this hole causing my issues. This time I have the same symptoms but the root cause is not the same. Maybe I lost the front cover o-ring? I didn't have any oil pressure issues so it wasn't likely but I pulled the front cover anyway. Yep, still in place and intact:
Somehow, I'm getting a jet of oil or excess pressure in the sump that's causing oil to literally shoot out of the oil filler neck. Everyone's knee-jerk reaction is "blow by" but how is blow by not an issue for 3/4 of the weekend and then suddenly becomes one? How does it suddenly go away (over Winter), not be an issue for another 3/4 of an event and then come back? I checked compression and it's no different than it was just a few weeks ago. I've consulted with numerous rotary experts and no one seems to have an idea. One thought I had was that because this is a late event occurrence maybe it's from me pushing the car harder. While it is true I was downshifting into 2nd and hitting the limiter more the acceleration, deceleration and cornering forces on the car weren't much different. Maybe a couple hundredths of a G higher, at best.
I refuse to pull this engine apart. It still starts, runs and makes great power. At this point I'm just going to accept this run with it. Send it, as they say. So if I can't identify the problem to fix let's just throw a bunch of band-aids at it. Step 1, let's modify the oil pan baffle. I never had this issue with an off-the-shelf baffle plate from Racing Beat with the stock oil pan. The baffle plate that came with the new pan was pretty different:
That's the newer baffle laid over a Racing Beat baffle modified to fit the new pan. The RB plate has fewer and smaller holes in the horizontal plane. This is a tried and true design and my original plan was to just rivet the two together. However, after some thought I figured it would be better/cleaner just to make an entirely new plate. Some 1/8" 6061 from McMaster, lots of time with a cutoff wheel and grinding bits and some help from a friend with a welder and I have this:
Changes/improvements: copied the Racing Beat baffle design to a new plate and welded in the original vertical baffles. Added some small drain holes immediately beneath the rear oil pressure regulator. Added a vertical shield between the rear oil pressure regulator and the dipstick/oil filler area to block any splashing. What's interesting is Mazda added a similar piece to the OEM pans sometime later in the production of the FC model. Speaking of the pressure regulator, one thing I noticed is the relief ports on mine weren't pointed in "ideal" directions:
There are two relief ports 180 degrees opposite each other. One was pointed downward toward the side of the engine and the other was upward toward the middle of the engine. Aside from using washers there's no spacing/adjusting the OEM regulator so after some thought I went with a unit from Atkins Rotary. It has a single relief port and a lock nut so it can be oriented in any way. It's also adjustable in that it can be disassembled and shimmed to change oil pressure. I was told it's a copy of the old Mazdaspeed/Mazda Competition design and I currently have it set for ~120 psi. With the lock nut I have the relief port pointed straight downward and it aligns directly with one of the drain holes I drilled in the baffle.
The next band-aid is baffling the oil filler neck. I figure if I physically block the path of the oil it can't spray out. Not wanting to completely choke off flow to the catch can I made three alternating plates that overlap by 1/16" and are spaced about 1" apart:
I also added a 10 AN port and moved it higher up the filler neck. I'm pretty happy with the finished product.
I'll have to be slower adding oil or alternatively use the oil crank angle port on the front cover. Speaking of, while my issue wasn't the front cover o-ring I kept reading about people having good results using a metal front cover gasket found in the Cosmos and later FDs. These eliminated the need for the o-ring and paper gasket. I've personally never used the paper gaskets - just the o-ring and small amount of RTV and have never had any issues. However, the concept of not having to clean RTV every time I pull the front cover or mess with the o-ring again was appealing. $25 later (thanks Mazda Motorsports) I had the gasket and quickly ran out to check it's fit.
Well, it doesn't look like that's going to work. Let's take some measurements.
Confirmed. Nope. The raised portion of the gasket that gets crush to form a seal lies outside the cast boss on my front side housing. WTH?! I was told any year could use this gasket and I know I've seen people use these on 12As and older 13Bs as well as the newer stuff. Well after some research apparently it's only my specific year range of front side housings that can't use this. Both the 85 and earlier 12As and 13Bs and 89 and later 13Bs have a wider cast boss that will properly crush the gasket. I've been told I can use the gasket if I use a small amount of sealant on both sides around the o-ring but I think I'm going to stick with what has worked for me. Note to self, in the future, when new housings are needed, consider the 89-91 version (although they don't flow as well).
My only other changes will be running slightly lower oil level - keeping it below the baffle plate and modifying my catch can system. It's still going to be a closed system but the fresh air source will be the charcoal cannister and instead of routing to the intake manifold via a PCV valve I'm just going to run a line to the intake duct. This should still allow the crank case to breath but at the same time won't be subjecting it to significant vacuum. Hopefully just enough to keep air moving.
That's more or less where I am now. I need to paint the oil filler neck and reinstall the front cover and oil pan (which is going to be pain). Hopefully this will allow me to get through 20 minute track sessions without filling the catch can and intake with oil. My next event is at Dominion Raceway in May.
When the oil level gets to be about a quart overfull, it will blow out of the oil filler tube at high RPM/load.
How often are you checking your oil level?
The oil passage boss thing is not an engine series thing, it is a production thing. I have used RX-8 cover gaskets on Series 4 engines multiple times, no problem. I was always using "old" parts though. Apparently there was a time during the production that they made S4 parts on S5 tooling and the bosses are "wrong". Mazdatrix had a page dedicated to it.
In reply to Pete. (l33t FS) :
For at least the first 6 sessions I was checking oil after every run. Pulled into the paddock, turned off the car, popped the hood, waited about 5 minutes then checked the dipstick and catch can. Each of those times the oil was right around the "F" on the dipstick and I got at most a tsp of stuff out of the catch can. I can't remember if I checked it after the 7th session. The last two were really close together and I basically had enough time to pull into the paddock, run to the restroom, then get back up into grid. After that last session though, dipstick was halfway between E and F and the catch can was full. I don't think fuel dilution is an issue (my car does run a bit rich to be safe) as the oil didn't smell gassy or feel watered down. It just seems strange it's only happening near the end of the weekend.
The RX8 gasket is pretty much the same as the Cosmo; just cheaper and includes the water pump housing as well, right? I'm very familiar with that Mazdatrix article. I have the side housing style that only uses the o-ring. No backup washer. I don't see how the metal gasket would adequately seal in my case. Sure the metal will be sandwiched between the front cover but that raised area is outside the boss so it won't be crushed. My understanding is that crush is what forms the seal. But you're saying you've used the metal gasket with what Mazdatrix calls an "early style casting" with no o-ring and sealant?
Right. It seals well enough to work.
There's no O ring on the oil pump (either end) or between the stat gears and the end housings, either. Oil's gonna drool out from places, it is normally no big deal. The bearing surfaces represent a much larger oil loss and you build lots of pressure despite that.
I mainly stopped using the O ring after I found it in my oil filter housing one time. That could get ugly fast!
For many years I had issues with my 12a spitting oil out the filler neck vent tube at drift events, eventually I put a longer tube on the vent and routed it to an empty Modelo can and I've never had to empty it. Also, even when it was puking oil, I never noticed the level drop on the dipstick, and the oil didn't really smell like fuel, so I didn't know what to make of that. Could there be an intermittent situation on track where you're getting positive crank case pressure and the oil is looking for the path of least resistance to move away from the pressure? Obviously the only real fix is to go full dry sump :) - which I'm told has a slight reverse supercharging effect on piston engines by effectively creating a vacuum pull on the piston as it comes down on the power stroke, not sure whether that would make any difference on a rotary.
Pete. (l33t FS) said:Right. It seals well enough to work.
There's no O ring on the oil pump (either end) or between the stat gears and the end housings, either. Oil's gonna drool out from places, it is normally no big deal. The bearing surfaces represent a much larger oil loss and you build lots of pressure despite that.
I mainly stopped using the O ring after I found it in my oil filter housing one time. That could get ugly fast!
his is machined for an o-ring. one of the chips motorsports service.
Since we're on the topic, I once read someone on Rx7Club describing a method he used. He would get a short section of copper tubing of a diameter slightly smaller than the passage in the front cover (presumably close enough for a tight fit), and put it in the passage before installing the cover.
His reason was for extremely high oil pressure pushing the front cover away from the iron (although in practice I kind of doubt that). But for pure reliability reasons, it doesn't seem like a terrible idea. The only downside is an overall decrease in the diameter of the passage.
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