In which I take an XP Miata hillclimbing to answer the question: Is Miata always the answer?

Yeah, we were really lucky nobody was hurt or worse. It took almost no time for the fire to grow out of control, and it became clear that there needs to be an evacuation plan in place at this venue. I think there will actually be someone responsible for making sure the pits aren't blocked and everyone can leave without getting trapped, from this point forward.

I felt particularly bad for the people who didn't get any runs. I hope the new people that were there for their first event give it another chance.

Event #7: Maryhill (September)

Goldendale, WA - September 15, 2018

Best run: 2:11.291

Run progression: 2:19.120, 2:16.078, 2:13.387, 2:11.291

(no official results published)

Tires: Hoosier A7, 245/40/15

Aero front: GV style lip, XP splitter rev. 1

Aero rear: Bumper cut, APR GTC-300 at 0deg AOA

Maryhill is the closest hill climb to me by a long shot (I live in the Tacoma area), so I'm hopeful that this little debacle doesn't prevent future events. I need to get my little Fiat to this hill sometime in the next year.

Thanks for the detailed posts about your experience. It's fun reading along!

You're welcome!

There's still no official word on the status of the event. I would be surprised if the Museum would stop us from using the hill next season, although I can't say for sure. Although there was a lot of vegetation that burned, there wasn't a great deal of property damage. A bunch of fencing will have to be replaced, though. In the end, this was an accident, not caused by carelessness, just bad luck. If you consider all the fires that happened along the gorge and in Washington in general, this was actually quite minor. Fingers crossed.

I took some footage of the fire, and put together a little clip, if you want to see giant flames taking over the hill.

So, the season is over, but the story doesn't quite end there.

I wasn't able to make the annual NHA meeting in Bend, it was just too far and I was driving down the PCH that weekend. When I was reading the minutes of the meeting, though, I suddenly noticed... my name.

We managed a class champion award in X Prepared! (I'm Henry, by the way). The fact that there were so many competitors in XP, and that I showed up to all but one event and placed between 2nd and 4th consistently paid off with this memento:

That's about as grassroots as it gets.

I was not expecting anything as I didn't know NHA gave awards in class. I also didn't pay much attention to where I ended up in my particular class, mostly looking at where I ended up overall. It's nice to end up with a benchmark to improve upon for next season. There are hundreds of people that run with NHA, and they only give out a few class champion awards. So, yay!

For some frame of reference, the second place car is an FC RX-7 with an LS swap. The first place car is a heavily modified WRX Sti with as much aero as they can legally hang on the car. So, the little car and I have our work cut out for us.

Speaking of having our work cut out for us, let's talk about what I need to do for next season. I want to improve the car in every way I can, but ideally without going too far in any one direction, still keeping it a balanced package. I'm open to suggestions if I can do anything better or cheaper or both.

Engine

I'm keeping the stock 1.8 right where it is. It might get a harmonic damper, it might not. If it doesn't I'll lower the redline even further. It doesn't seem to be faster to get those last few hundred rpms in each gear on the hill, it's sometimes faster to stay in a higher gear and avoid shifting by driving with two feet. There's also less heat soak when short shifting a little. So I'm not building a motor this year. Will the stock motor hold up? Only one way to find out.

Upgrades here are going to be -

• M-Tuned coolant reroute (installed already)
• Injector Dynamics 1050x injectors
• Some kind of cool air ducting around the intake, anything is better than what I have now
• ARC Superchargers electric supercharger
• Solid motor mounts (haven't decided on vendor)
• Bigger intercooler (Ebay? FM?)
• Better ducting around the intercooler/radiator

It was clear towards the end of the season that the RX8 injectors were running out of duty cycle, the engine never pinged on the hill, but it did after I installed the coolant reroute at autocross. I turned down the boost until I could get the bigger injectors.

Brakes

I don't think I need to change much in this department. The stainless lines are a dramatic improvement, and make me want to eliminate some of the pedal flex. I need to look at bracing the master cylinder. Otherwise, the 1.8 brakes and Hawk HP+ have been good enough that I don't feel that I'm going to make great gains here. If there's a way I can lighten the stock hardware without weakening it, that might happen.

Grip

More is faster, more is better. There's no limit on wheels or tires in XP, but there's no more room under my fenders. I'm not letting that get in the way. Upgrades here are:

• 15x11 6UL
• 275/35/15 Hoosier A7
• Fender flares of some description (Carbonmiata?)
• ARP wheel studs

Drivetrain

Sticking with the five speed until it breaks. I will switch it over to the Motorcraft fluid, I think it might be happier. The FM level 2 clutch is a monster, I'm quite happy with it and it should support whatever power I can make. So, there's just a bit to do here:

• OS Giken diff
• 3.636 ring and pinion
• New diff seals and poly diff bushings

Aero

The wing is brilliant. I might need to add some reinforcement to the trunklid or under the fenders before I add the gurney flap, though. I want to improve both the front and rear downforce:

• APR GTC300 gurney flap
• Larger front splitter (it can extend another 4 inches or so in front of the bumper)
• Longer front endplates
• Front supports for the splitter

Weight reduction

This is a big deal and is a place I can make big improvements without spending much. Things I can do:

• Remove headlights completely and replace with lexan panels
• Remove windshield wipers and drive mechanism
• Remove mirrors
• Gut doors + add window net
• Remove dash and heater/blower motor/ducting
• Remove trunk hinges/spring
• ???

I'm sure I'm missing stuff here, but that's off the top of my head.

There are a bunch of other little things, but those are the main things that will make the car faster. How much faster? I don't know. I'm not sure how much power I will make yet, or how much weight I can lose. In the end, I think the biggest improvement will have to come from the driver.

Electric supercharger is actually being made now, and should be arriving in a couple of weeks.

I hope I can make everything work together. Boost is boost, right? I'm not sure if having two turbine compressor stages plumbed closely together in sequence without a blowoff valve between them will have issues with compressor surge. The supercharger doesn't have any excess energy to keep it spinning off boost, though, so I'm hoping that the pressure differential between the two compressors will be negative off boost as a result. I'm also a little worried that all the airflow through the supercharger when the turbo is fully spooled will cause it to overspeed, but it's a centrifugal supercharger so maybe it shouldn't matter? I'm also slightly concerned that the supercharger might become a restriction at high RPM. A bypass valve would address both of these issues, but I'm not sure they are real issues yet.

Supercharger compressor outlet is 2" OD. The inlet of the GT2560 is slightly larger (I need to measure it as I haven't been able to find the exact dimensions anywhere), but not significantly. I think the turbo has enough room in front of it to couple the supercharger directly to the inlet, though I'm not sure exactly where the intake will end up. Ideally, behind the headlight assembly. Mounting the supercharger will probably require some creativity.

Of course, there's always the worry that this is just an expensive experiment that won't net any gains or won't work at all. I have set my expectations pretty low. It's true that OEMs are investing heavily in this technology, but they are actually doing like, math, and stuff.

Electric supercharger shipped out today!

Also, since youtube embedding works again, I went through and updated all the links, so the thread looks the way it should now. I think it's much nicer to be able to see thumbnails of the videos and be able to watch without leaving the thread. Yay!

That is an interesting supercharger!! It was only a matter of time before someone used a big ass brushless motor. Should be infinite boost control that way too.  My only complaint is they need a bigger battery.... But that should be easily remedied. And this almost looks DIYable if you can find a good compressor match to the high RPM brushless motors.... That appears to be a off the shelf motor....

What was the cost? 

The ARC kit is $2999. 

https://arcsuperchargers.com/contact/

I can't say if the battery pack is going to be big enough for the longer hills yet, but it should have more than enough capacity for autocross. 

Your hills look fun (when they aren't on fire). Maybe I'll do a longer trip and visit some events outside of New England in 2021 or 2022.

I also prefer them when they aren't on fire! By all means come out and run with us, we'd love to have you.

This thread has been quiet because strange things are happening under my hood...

Nothing to see here, move along!

So many little things. Because I have to figure out how to mount everything and where it will go, I've been managing to overthink everything.

What an adorable little heat shield!

Going to try and keep the breather filter from melting.
What else...

Had to add the toggle switches for arm and charge to the center console.






Modified the MS2 to output all the things the control module needs on pins 9-11 of the DB16 connector.




Mounted the control module on the passenger kick panel.





I thought it might need more than a single strap but it was way more secure than I expected. It doesn't weigh much. The battery pack will get more straps.

It's so close to being ready to run with compound boost. I have an autocross event on Sunday, so it's going to be done by then one way or another.

Bremerton Sunday?

Yup!

I'm registered to run in the afternoon, in Prepared, whee. Will you be there?

Updates... engine bay is done. At least for the next few minutes. I think I need to trim a zip tie, lol. The physical part of the install is done, I still need to make a few last electrical connections.

It runs happily like this, I drove it around for a while to make sure nothing is melting or catching on fire, and the car is much quieter but seems to spool a bit quicker. I think my new, very expensive active cold air intake plumbing is extremely good at delivering cold air to the turbo. Let's hope that it's even better when it's turned on and creating pressure differential. The difference in intake noise between the FM air filter and this giant twin-cone 3" is dramatic, but so is the difference in filter material surface area.

I can actually hear the turbo spin up now, which is quite nice.




The 'headlight' is just to keep me legal during daytime transits to events. It does actually work fairly well. GRM Secret Santa delivers! Thanks Secret Santa!



As for the interior...




Everything is mounted, wiring is run everywhere except to the main power and the charge/arm switches. I'll do that in the daylight. Battery pack is down low and central, the controller has to be where it is or I'd have to extend the wiring harness for the supercharger.

It's so close though.

I think I'm going to run the power feed off the back of the starter relay. I don't want to run a heavy cable to the trunk when there's already one there that only gets used for a few seconds at startup. Is this a bad idea? I can't think of a reason not to do it.

In reply to dr_strangeland :

Unfortunately no I won't be there. I didn't realize you were going to bring this to autocross also. I'd love to check it out sometime oh, very very interesting supercharger idea. I've played with large brushless motors and I can see this working well. As long as you can feed it the power needed.

My dad will be there in his BRZ. Look for the old guy with the white hair, red car.

I don't see any reason not to use the lead to the starter, what size is it? You're going to want as little voltage drop as possible.

It's big enough to supply a couple of hundred amps at 12v to the starter during cranking. It's much, much heavier than the charge lead for the battery pack, so I think it'll be ok.

I feel like you are describing Scott Engler. He's been campaigning that BRZ for the last three seasons at least.

In reply to dr_strangeland :

He's the one :D BRZ is his full time racecar Now. He's my dad ;) 

Yeah I figured, I think that the lipo pack may be undersized tho.... That's my only worry with the system (although likely fine for autox) I'm looking forward to your report! 

Your dad is awesome. He was really encouraging when I was a novice, it made it a little less intimidating to see him at every event. There are a lot of very serious people at the NWR events, it's nice to see someone a little more relaxed and making sure the n00bs know they are making progress.

I took my first compound boosted pulls today. It's too early for a full report, but the results are promising. If anything, I might have trouble getting the boost to a low enough level for the stock motor. I'm going to turn the EBC all the way down. Pretty sure I was hitting boost cut and that's set at 21 psi.

Tomorrow should be interesting!

I think the first issue I'm going to have to solve is the recharge time. I need to charge the battery pack a lot more quickly, so I'll have to find a way to do DC-DC conversion at a much higher current level. 

I'm also considering building a battery pack out of lithium motorcycle batteries. I don't consider these to be insurmountable hurdles.

That was my concern too small of a pack. Whats its Ah rating? Voltage?

Seems you could build a lipo pack from RC batteries pretty easily, and maybe just swap them between runs? I did a 16ah 52V nominal pack for a couple hundred $.

I'll have to ask. The controller is going back, it has an issue that is beyond my ability to troubleshoot.

I have to duct the supercharger compressor and motor to keep it cool. Heat is a big issue in there and the motor won't like it when ambient temperature rises. I am just going to duct the entire headlight opening around it and see how that works. It was getting uncomfortably hot, and will go into thermal protect at 75c, so I need to get ahead of that issue.

This season is going to be a period of development and I'm setting my expectations accordingly. I think there will be a lot of failures on the way to a working system. I didn't get a proper run out of it, so no video, although the car was faster than it's ever been. I think the ID 1050s are giving me better fueling and the intake is giving me less restriction and colder air, so even though I'm running less boost with just the turbo, the car is quick.

I am thinking I can build a battery pack that's large enough for several minutes and simply deplete it over the course of a heat or session. I need about 7-8 minutes. The other possibility is charging in the pits from a lead-acid array.

From the website it looks like hes simply using RC lipos to build his "pack" I am sure you can do the same and make it bigger. 

Watch lipo charging, that last 10-20% is really hard to get into them. I am not sure its feasible to charge quickly from a lead acid source.

I can see heat being an issue in a hurry! your pushing a poop load of amps, know the kw rating of that motor? 

8kw afaik. I have a lot of fresh air available luckily, I just have to duct it so it's not in the airflow behind the radiator.

I don't need the last 10-20% though, if the pack is sized appropriately I can quick charge to like 75% and then run again. That's how mobile phone fast charging works, you only get about 60-70% at the super fast rate, then the charge controller has to back off.

Video from Sunday! Running only about ten pounds on EBC, it's almost as low as I can set it. When the supercharger was working I was hitting overboost, so I had it turned all the way down. Of course, didn't manage to get a run with the supercharger so we'll have to wait until I get the controller back. The problem has been identified, but I don't know enough about it to say much. Hopefully I have it back next week.

The car was still faster than it's ever been, I think the ID1050 injectors and new intake plumbing are responsible for this. I have done a bunch of street tuning on the new injectors and the car is really happy. Sounds really good, too.

I'm trying to spend more effort on the editing, I feel like it's so much nicer to watch videos with some polish and pacing. Should be an interesting season.

And some pictures of the car in autocross trim. Splitter is gone until I make a new one. It actually sucks for autocross because it takes out cones I would otherwise miss. Getting that extra 6-8 inches closer to the cone is better than adding some high speed grip I don't get much of a chance to use.

Thanks to the course designer for a fun layout! It was nice and flowing.

I kept away from the car when the hood was open. Too many questions about the system I can't fully answer yet. The system inspires a lot of speculation from people, though.

It needs to cool a lot, I have to do some ducting around the supercharger motor, autocross tends to heat soak everything, but I think ducting the entire headlight opening around the compressor assembly will still help a lot. Mostly I need to stop the radiator fan from blowing directly onto it. The coolant reroute has been very effective at getting heat into the radiator.