E30 Rally Build Thread

[MasterOfPuppets]

So, in the interest of not having to explain to a mexican exhaust guy "don't cut this" and "I want to keep the cat-back," I just went ahead and pulled it myself. I actually managed to not break any of the bolts and the whole thing came off pretty easy. Total weight for the cat back and hangers was 37 lbs. It's actually pretty quiet, too.... it almosts sounds good...

Looking at the underside of the car, I think I'll actually have the guys route both exhausts out the drivers's side. There's already a channel there since that's the way it ran originally, and that way I avoid getting near the gas tank. And then the driver gets full volume!

[iamsam]

So, in the interest of not having to explain to a mexican exhaust guy "don't cut this" and "I want to keep the cat-back," I just went ahead and pulled it myself. I actually managed to not break any of the bolts and the whole thing came off pretty easy. Total weight for the cat back and hangers was 37 lbs. It's actually pretty quiet, too.... it almosts sounds good...

Looking at the underside of the car, I think I'll actually have the guys route both exhausts out the drivers's side. There's already a channel there since that's the way it ran originally, and that way I avoid getting near the gas tank. And then the driver gets full volume!

Awesome!! Are you going to keep it two separate pipes exiting the side of the car?

[MasterOfPuppets]

Awesome!! Are you going to keep it two separate pipes exiting the side of the car?

Yep. And if I can find hi-temp paint in the right colors, I'll paint one of them blaze orange and one bright blue.

[iamsam]

Yep. And if I can find hi-temp paint in the right colors, I'll paint one of them blaze orange and one bright blue.

Oh my goodness. Just get some tasteful chrome tips and call it good.

[MasterOfPuppets]

Exhaust

So I got the exhaust done today. Came out pretty good; the only negative was that I had to have them weld the pipes on rather than use bolt-in flanges because "that thing has weird flanges." So if I ever have to redo it, it will be have to be cut off. No big loss.

So, without further ado, here's how it came out:



Pretty wild, I know. A closeup:



You can only see a gap between pipes and car if you're at a low angle, otherwise it looks solid. The guys did a great job with it; here's a shot from underneath showing the routing:



And a closeup to show the clearance to the subframe bushing.



As discussed earlier, I'll heat wrap the exhaust and/or make a little heat shield for it. Really, though, after a few hours of cruising around today, I never noticed any heat inside or outside the car. I think that's the advantage of a tiny 2.5L - doesn't move much gas around.

Here's a video clip to try to show the sound of it. My camera definitely emphasizes the high frequencies, so in reality there's a bit more bass to it. The volume is tolerable but should be loud enough for me to hear on stages.



Overall, I'm very pleased, and the whole thing cost me $130 and took 4 hours for the shop to do. I'd estimate a loss of 30 lbs as well.

Here is a link to the place I had it done. If you're in ABQ I strongly recommend them. It's called Discount Radiator & Exhaust Service at 807 San Mateo Blvd, just south of Zuni.

I whipped up a quick camera bracket today using a $2 right angle bracket kit from Walmart. Amazingly, two existing holes in the front of the roof lined up with the holes in the bracket, so a screw and a rivet later I was good to go. Here's the bracket (the camera will screw into the lower front hole and sit on top of the bracket):



Here's a shot from the camera when mounted in the bracket:



Should work out well. Get ready to see some videos from that point of view after this weekend's rally day at CORE.

Meanwhile, my tachometer decided to quit working once and for all. So I fixed it:



German car, German supermodel. And do you ever need a reason to put a picture of Heidi Klum anywhere?

[iamsam]

WHOA! That exhaust sounds pretty dang good, especially in the high rpm range!! I strongly approve. Very good fab work too. Also, you should spray the pipe and weld w/ some high temp paint to try and stall rusting, because you will get that in northern MI.

man! I can't wait till this weekend! That thing is gonna be a beast around the track.

You should do more high rpm exhaust sound recording.

[Frog]

I almost built a rally e30 instead of my current track build. Only reason is that, surprisingly, in this dirt lovin redneck state, there is no rally sport in GA. Epic bu
Ild, thanks for sharing!

[MasterOfPuppets]

I almost built a rally e30 instead of my current track build. Only reason is that, surprisingly, in this dirt lovin redneck state, there is no rally sport in GA. Epic bu
Ild, thanks for sharing!

Get out there on the dirt oval with the sprint cars! I'm sure you could be competitive.

But seriously, sprint cars are badass.

[MasterOfPuppets]

Rally at CORE as a shakedown

So I took the car out to CORE for a day of rally practice and car test this weekend (full pic thread is here). From the car design point of view, I had a few objectives:

1.) Learn to rally the LSD/manual combo
2.) Evaluate the car's reliability
3.) Evaluate my mods to the car
4.) Identify potential improvements

The last time we were at CORE is was a dry dustfest, so that's what we were expecting this time. However, when we arrived, we found that much of the track was covered in puddles in all the wrong places (e.g. in a banked corner, the low part.) This meant that as soon as anyone hit a puddle and spread water over the width of the course, that corner became impassable. We got stuck several times and slid off the track many more. Probably a good experience in obstacle avoidance and bad conditions, but not good for someone focused on car control and finding the right line through a normal corner.

So, in the order of my objectives above -

1.) Within five minutes of starting to rally, the LSD was no longer L. No idea what caused it, and it still works fine as a one-wheel-wonder, but slip is no longer limited. Pretty irritating, really, since one of the main reasons I bought this particular car was for the 4.10 LSD... oh well. I'm debating welding one up and going locked to remove any concern for reliability... we'll see.

As for the manual, I did get good practice, especially heel-and-toeing, but since the clutch is veeery slippy it's hard to say if I'll be any good when I get a grippy clutch in. I at least got in the habit of getting my feet in the right position coming up to a turn.

I also found that the BMW shift pattern is my arch nemesis. In every other manual I've ever owned or driven, including my current Z06 DD, the shift pattern is something ending in "RUR," in this case "6RUR":



The E30 5-speed, though, is of course a "5UR-RUL." What this means to me: when I want to do a 3-2 downshift, which seems very common on a rally course, I basically yank the lever down and to the left with quite a bit of pressure to the left. On my Z06 especially, there's a good bit of L-R spring pressure to overcome to go into first or second from third or fourth, in fact almost as much as to put the E30 into reverse. So in the E30, when I attempt to do a 3-2 downshift, I pull down and left on the shifter which slides it into the reverse slot but obviously won't let it pull back since there's no gear there. This is especially apparent in any kind of bumpy situation since any kind of finesse with the shifter goes out the window. I probably did a 3-nothing heel-toed downshift hundreds of times on Saturday :curse:. Here's an example of an attempted 3-2 downshift, at :03 you can hear the throttle blip as I go for the heel-toe, then you can hear the engine revs fall off and then pick back up at :06 when I find second:



I'll fix this by simply putting a reverse lockout bar next to the shifter, so that when I pull left it hits the bar and stops in the 1-2 slot. The bar will of course be removable so that I can use reverse if need be, which will hopefully be rare in a rally stage...

Man, this is a long post...

2.) Other than the insta-fail LSD, the car proved extremely reliable. The only minor issue I had was the front plastic brush guard and fender liners all ripping off. I figure they would have been pulled anyways and replaced by suitably heavy-duty steel, but I definitely validated that reqt. The suspension took a pretty good flogging with no apparent negative effect (which was surprising, honestly).

3.) My mods all worked out great. The engine stayed cool even during extended flogging, no doubt in some small way due to the hood vent and AC removal. The roof vents were awesome and only pulled in mud if I really screwed up. The shift knob worked great. The hood pins worked despite being coated in mud. I never wore sunglasses the whole day and was never blinded by the sun's reflection off of dash or hood. And the Bilstein HDs handled everything I threw at them, including some air time:





4.) I came up with a long list of future mods to the car, especially if I ever have the need to race in mud again:

- Reverse lockout bar
- Mud flaps (required anyways)
- Grippy pedal surfaces
- Grippy floor surface beneath the pedals
- Supportive seats (I was running stocker non-sport seats)
- Much better wiper sprayers
- Bigger wiper fluid reservoir (maybe)
- Tires with tread
- Better underbody protection

I was pleasantly surprised by the performance of the suspension. While I will probably still go for a coilover conversion, this setup really isn't too bad. It absorbed everything CORE threw at it pretty well, which I can't imagine is too much smoother than an actual rally stage. Coilovers, another inch of ride height and an inch bigger tire and I'll call it good to go.

[KennyT]

On the shifting topic: You are trying way too hard. Slow down so you can be smooth. You probably don't need to be heel-toe shifting either, most competitors just drive the transmission hard and replace the clutch as needed. An OEM capacity or slightly above would be fine. The reverse lockout is a bad idea as the transmission will rotate and may jam gears. Do you have a short throw shifter installed? A longer throw might do you well in this case.

Fender liners and underbody protection: HDPE is the answer. You will probably want to make panels to completely block off the engine bay from underneath.

Pedals/Floor: Skateboard grip tape. 3m stuff may be cheaper and available at Lowes, but the skate stuff should hold up better.

[MasterOfPuppets]

On the shifting topic: You are trying way too hard. Slow down so you can be smooth. You probably don't need to be heel-toe shifting either, most competitors just drive the transmission hard and replace the clutch as needed. An OEM capacity or slightly above would be fine. The reverse lockout is a bad idea as the transmission will rotate and may jam gears. Do you have a short throw shifter installed? A longer throw might do you well in this case.

Fender liners and underbody protection: HDPE is the answer. You will probably want to make panels to completely block off the engine bay from underneath.

Pedals/Floor: Skateboard grip tape. 3m stuff may be cheaper and available at Lowes, but the skate stuff should hold up better.

Thanks for the feedback! All points taken, but a few clarifications and follow ups:

I try to heel-toe not for clutch preservation but to avoid loss of rear wheel traction when the low gear engages and spins up the engine. I thought I could get away from it but ended up spinning pretty good a few times approaching turns. May be a technique issue but I figured it was an important part of rallying...

On the shifter itself - I find this happening even on the street, so it's not entirely a hurry-up-and-shift issue. And I try to keep telling myself "slow is smooth, smooth is fast..."

I don't fully understand the problem with the lockout, is your idea that the shifter will torque the trans around the pivot where it hits the proposed lockout bar? I really don't apply much pressure to the left, I think the spring in the trans/shifter is just a bit weak after 270k miles. But yeah, taking some time and concentrating a bit more on shifts would be better in this case.

And on HDPE... I guess it's better than steel from a weight point of view, but I'd much rather fly off the road and grind across rocks on a steel underbelly than plastic. I'll hit a few rallies and see what works for folks... I now have one vote in the "HDPE" column.

[KennyT]

A 270K transmission definitely explains things. I'm more used to the pair of 120k G260's I have and the 60k Roadster box. You could crack open that transmission and replace the 1st and 5th alignment springs with new/stronger.

You will want to protect anything important (oil pan, fuel tanks, fuel crossover line, etc) with at least .250 Plate Aluminum. I wouldn't use steel for the sake of weight. Anything that just needs to be shielded from rocks and sand (swingarms, axles, subframe bolts, wheel wells, etc) should be protected by HDPE. At the first night of Oregon Trail my driver hit a dividing fence, trashed the front quarter panel, and chucked the wheel liner. I was able to reinstall that liner without any issue. HDPE is awesome stuff.

For the rest of the rest of the belly pan you don't need anything other than maybe spray on bedliner. The pan will be shiny after every race and you just respray it after patching the cracks and holes.

[SlapDash]

What's a good pliable thickness on the HDPE sheets?

That was some seriously muddy E30. Nice work!

[MasterOfPuppets]

HDPE is awesome stuff.

Where to buy?

[rstraugh]

1.) Within five minutes of starting to rally, the LSD was no longer L. No idea what caused it, and it still works fine as a one-wheel-wonder, but slip is no longer limited. Pretty irritating, really, since one of the main reasons I bought this particular car was for the 4.10 LSD... oh well. I'm debating welding one up and going locked to remove any concern for reliability... we'll see.

That sucks. I had no idea that it would fail anytime soon.

What about taking the clutch packs from the stock 3.73 LSD and putting them in the 4.10 LSD? Or go the other route, take the gears from the 4.10 and put them in the 3.73? The 3.73 will have the lowest mileage. It might require re-shimming... You could take the diffs to a transmission shop and they might be able to do the swap for you.

Of course there is always the quaife option ($$$).