1987 E30 Coupe Rally Build

Knurled. said:

Looking at the pics of the ultralighted Miata, it was doing a Dutch roll in every corner.  It would understeer a lot less and have much more consistent handling if they stiffened the front a bunch.  That is probably why they were messing with diffs on Saturday night.  They were attacking the wrong problem.

 

Dirt handles different, you get more grip the more you can drive the outside tire down into the surface.  The trick is to get a suspension that can both do that, and follow the ground contours.

 

Look at Vaughn's 924 for comparison.  He's always got the car back over the rear axle.  That is a combination of good suspension setup and forceful driving.

It doesn't hurt that like 58% of his weight is over the rear axle to start with, lol

In reply to irish44j :

Helps a whole lot, actually 

Although I don't know how that is possible.  The back of the car is Lexan and carbon fiber and duct tape and a dozen screws, and an 016.  The fuel tank is under the hood.

Since I needed to re-do my exhaust (both for noise and ground clearance), I decided to check out the eBay headers that I've been hearing some people have success with. Granted, most of the positive reviews I've heard have been on m5x engines. Nevertheless, they were less than $100 shipped and look great. 

Unfortunately, I ran into an issue with oil filter clearance immediately:

Granted, I didn't have it bolted down in these photos, but I'm guessing that once everything is fully installed it'll have 1-2mm of clearance at best. I suspect that might influence my oil temperatures a bit. 

My oil filter sticks out a bit farther than stock because I have a sandwich plate adapter that I mounted my oil pressure gauge sender to, but I think it would still be an issue without that. I'm going to search the internet and see what sort of solutions other people have come up with. 

I don't think relocation kits are too expensive. 

In reply to AxeHealey :

Yeah, that's looking like my best bet. $43 shipped isn't too bad, and it seems universal enough that I could reuse it on another engine down the road if needed.

Welp, after fighting with the ebay headers, I decided to give up and go back to the stock manifolds. The clearance to the oil filter was tight and required relocating the oil filter, and the collectors were practically touching the control arm bushing. So yes, I probably COULD have made them work with enough hacking, but it didn't seem worth the hassle. The idea behind this car was supposed to be to keep it simple where possible, and spending a bunch of time modifying ebay headers which would also complicating the oil filter mounting wasn't the right direction. 

That said, I did a lot of work to tidy up the merge from the two pipes that come out of the factory manifolds, tucked the whole thing up closer to the body, and added a "muffler" to keep the sound police away. The muffler is from Vibrant and is essentially a big resonator, and I mounted the cat directly upstream of the muffler so you can still see it if you shine a light into the tailpipe. My biggest concern with the exhaust at this point is the V-bands getting ripped off on stage as they're the lowest-hanging parts of the exhaust, but I'll keep an eye on them at rallycross and reconsider their placement later. 

I suck at build threads so this is the only picture I took of the whole thing:

I bet that sounds nice.

In reply to AxeHealey :

It's not bad, much deeper tone than what I had before. The old exhaust was relatively mellow and deep until about 4,000RPM, where it would start screaming. This iteration doesn't "come alive" as much as the old one, but it still sounds pretty good. 

I find it interesting how different the exhaust sounds, even though the components haven't changed all that much fundamentally. It's always been 2.5" pipe, I'm using the same cat as before, but instead of a glasspack pre-cat I now have a vibrant muffler (basically a big glasspack) post-cat. 

Allow me to put your fears to rest- those V-bands will definitely get ripped off on stage.  I would either relocate them to be above floor level, or weld metal wedges to the exhaust ahead of them so they can be pushed upwards instead of just catching on stuff.

In reply to ¯\_(ツ)_/¯ :

I sort of figured that'd be the case but I appreciate the confirmation haha. Unfortunately it's tough to get the upstream one above floor level, so I may have to add the wedge for that one, but I think the downstream one will get relocated to be after the subframe where the exhaust comes up to the trunk area. 

In reply to artur1808 :

Can you get the upstream one right near the skidplate, and put a kickdown on the plate to protect it?  The V-band on my car lives in a spot where I hammered the trans tunnel out to tuck it above the rear of the skidplate, seems to be pretty safe there.

¯\_(ツ)_/¯ said:

Allow me to put your fears to rest- those V-bands will definitely get ripped off on stage.  I would either relocate them to be above floor level, or weld metal wedges to the exhaust ahead of them so they can be pushed upwards instead of just catching on stuff.

I was about to say the same thing. Those v-bands will be gone in no time on stage, and so will your nice exhaust (btw, Vibrant muffler? looks just like mine). 

I would just weld the whole thing and make the only exhaust flange at the header collecter. WIth multi-piece exhausts, I've managed to rip ALL of them apart doing this, especially at the rear half where they are so vulnerable going under the subframe. Weld them up, then double-plate them with a half-section of piping on the bottom. 

irish44j said:

artur1808 said:

I just remembered that I spotted a Saab at the last rallycross with GRM stickers and one of the few vanity plates I've ever liked:

I never got a chance to meet the driver but I'm guessing this is someone from this forum??

that's Brian (paranoid_android on here)

And you'll chuckle that the sticker at top right for "Dirty Industries" is for a DC-based e30 rallycross team who he crewed with at SOFR last weekend. 

Lol, that’s me!  That was my very first rallycross.

@irish44j- in all fairness I was wearing my Pitchblack T-shirt that day too ;-)

In reply to paranoid_android :

Dang, not sure how I missed you! Well hopefully you enjoyed it enough to come back to another event. I'll be sure to stop by and say hi if I see that saab again. 

In reply to irish44j :

Yep, Vibrant "streetpower" or something like that. It's basically a huge resonator; you can see right through it haha. 

Good call, I just liked the idea of having multiple sections for the sake of serviceability and being able to remove that one section if I needed to get to axles, diffs, trailing arms, etc. I guess it's not that much work to remove a larger section of exhaust, especially if it means keeping the exhaust attached to the car!

paranoid_android said:

irish44j said:

artur1808 said:

I just remembered that I spotted a Saab at the last rallycross with GRM stickers and one of the few vanity plates I've ever liked:

I never got a chance to meet the driver but I'm guessing this is someone from this forum??

that's Brian (paranoid_android on here)

And you'll chuckle that the sticker at top right for "Dirty Industries" is for a DC-based e30 rallycross team who he crewed with at SOFR last weekend. 

Lol, that’s me!  That was my very first rallycross.

@irish44j- in all fairness I was wearing my Pitchblack T-shirt that day too ;-)

lol excellent :)

artur1808 said:

In reply to irish44j :

Yep, Vibrant "streetpower" or something like that. It's basically a huge resonator; you can see right through it haha. 

Good call, I just liked the idea of having multiple sections for the sake of serviceability and being able to remove that one section if I needed to get to axles, diffs, trailing arms, etc. I guess it's not that much work to remove a larger section of exhaust, especially if it means keeping the exhaust attached to the car!

Yep, same muffler I have.

I also recommend thinking of solutions for exhaust hangers. The stock stuff will NOT hold up to rally. I am using the same solution Nonack uses (at his suggestion) and I've found them to hold the exhaust extremely well.and the way I set it up, they are quickly removable with an impact, no messing around with the annoying rubber donuts or whatever.

See my build thread, page 95l, about halfway down (with additional exhaust-buildign stuff the page before I think). 

¯\_(ツ)_/¯ said:

Allow me to put your fears to rest- those V-bands will definitely get ripped off on stage.  I would either relocate them to be above floor level, or weld metal wedges to the exhaust ahead of them so they can be pushed upwards instead of just catching on stuff.

I told him that in person the other day too :) 

artur1808 said:

In reply to paranoid_android :

Dang, not sure how I missed you! Well hopefully you enjoyed it enough to come back to another event. I'll be sure to stop by and say hi if I see that saab again. 

I actually recognized an image of your car in the Volvo Rally Build thread, which led me over here.

Honestly going to the Thistle Hill event was very awkward because I didn’t know a single person.  Had I been at an event in the DC Region or one of the Ohio regions, I would have certainly known someone.  Kinda crazy...

In reply to fidelity101 :

Yeah, so there will definitely be an exhaust 3.0, but for now, version 2.0 will have to suffice with these v-bands as they are haha. 

In reply to paranoid_android :

Dang, I wish I had known a fellow GRM person was there! I try to make it to all of the Detroit region events, and you'll be likely to see Kevin (fidelity101) in his rx7 at a good amount of events as well. We will do our best to make it less awkward for you next time you come by! 

Not a ton of exciting news, but I'm planning on taking the car up to a friends cabin this weekend to do a little bit of "testing" on some of the gravel roads/trails up there since it's quite remote. So I did a quick "nuts and bolts" check on the car yesterday after having driven it to work the last few days and the only thing that shook itself loose was the bolts that hold the axles to their flanges in the diff. This is my own fault as I'm pretty sure they're not meant to be reused. I figured a bit of loctite would do the trick but they were still less-than-tight. Note to self: order some new hardware for that...

Had a bit of spare time so I decided to finally tuck the bumpers on the car. This is something I've been meaning to do, and now that it's done, I'm not sure why I didn't do it sooner. The bumper "struts" on the front weren't compressing even after drilling them out so I made a simple bracket and bolted the bumper right to that in a "tucked" position, but the rear worked just like the internet said it would. Naturally, I suck at taking pictures so here's a "before" from back when I first brought the car home:

and after:

I think rally cars go through exhausts like candy, its just the nature of the beast, which is why I typically try to find thick walled tubing when I have mine made. I think I'm on version 6 of my exhaust if it makes you feel any better, working on #7 right now lol.

fidelity101 said:

I think rally cars go through exhausts like candy, its just the nature of the beast, which is why I typically try to find thick walled tubing when I have mine made. I think I'm on version 6 of my exhaust if it makes you feel any better, working on #7 right now lol.

my current version I made myself. Looking at where the previous exhaust had been hit, dented, and broken, I made localized reinforcements and "armoring" (i.e. double-plating) in those sectons. That said, all we've ever really done is break a muffler-to-pipe flange on stage (NEFR last year). 

A couple things that I was about to post in your other thread, but will just leave here as food for thought:

------- 

I will note: I highly recommend putting the factory hood hinge mechanism back. on (but replace the pivot rivets with removable pins). For several reasons:

1. Unlike most cars, the e30 hood is great in that if it comes unlatched or the hood pins break, it won't go flying off. And yes, this happens in rally more than you'd expect. Forget if you basically hit anything, your hood pins aren't going to line up. I guess you just ditch the hood at that point. 

2. Having to take the hood completely off the car every time you just want to check something is highly annoying, especially on stage. Go find the video of Dan Downey (who has his just held on by the pins) throwing this hood over his head into the woods in frustration when trying to fix something on the side of a stage, lol. Your crew also won't appreciate it, especially if it's a crowded/muddy/windy/rainy paddock at service. 

3. the tiny amount of weight saved is more than countered by annoyance. I've had my hood that way, I'm speaking from experience ;

In truth, I don't make much of an effort at weight reduction, because I don't think it really matters unless you're one of the top drivers on the stages (which I am not).  I also don't think there is any significant amoutn of weight to be lost on an e30 in the first place, for rally, due to requirements.  The place to lose weight is in you and who your codriver is (Jim is about 165lbs, but I know there are some corn-fed guys out there in some cars). Or in what gear you carry. I know guys who carry pretty much nothing that isn't explicitly required by the rules (i.e. no tools, no snacks, no quick-fix items). Maybe that works for them. More often, they're the guys who are asking around between stages for who has a  "xxx-size nut and bolt" or a particular tool between stages. A lot of them are also the ones who have proportionally more DNFs, coincidence or not.

YMMV, but weight reduction in a rally car is a diminishing return from the very start.  This isn't rallycross. 

PS - you guys doing PS delete for rally are crazy.........

In reply to irish44j :

Yeah, I hear what you're saying. A lot of my "weight reduction" has actually been driven by reducing complexity as much as possible, which also has the benefit of reducing weight. I quickly came to dislike the forward hinging hood due to it making servicing the front of the engine bay a pain in the butt. Granted, I could have done your method of having some removable pins in the pivot points so I could pull it off easily when needed. As far as hood pin alignment after hitting something, I don't think that would be a unique scenario to not having hood hinges. Wouldn't you have the same problem of pins/hinges not lining up if you hit something with the factory setup?

I agree that rally cars are rarely light, especially at the grassroots level. However, my mentality has been that if I can reduce the weight a bit or take steps to improve front/rear balance of the car, why not? In the case of engine bay weight reduction (hood hinge/latch, power steering, ABS, etc) these are all things that (in my opinion) aren't necessary. Obviously a big skid plate, skid reinforcement, lights, etc will add a bunch of weight, but if I can offset some of that, I might as well. I actually enjoy not having power steering; I've daily driven and rallycrossed a bunch of miatas without power steering and got used to it. Even at stage rally speeds a few weekends ago when I took the car up to northern michigan for some "testing", I didn't have any issue with it. It's really only noticeable at parking lot speeds in my opinion. 

On the topic of gear/tools in the car, what sorts of small parts/bolts do you carry? What I did in the Jetta and intend to do in this car is to carry spare, jack, impact, fuses, basic tools, ibuprofen, and water. (in addition to the first aid kit and whatnot that are required) What do you carry in terms of quick-fix items and nuts/bolts? I've always thought it would be good to have a variety of hardware, but haven't given much thought to what that should be and how I'd organize it.