BMW Compact Build

I may not be quick like you guys yet, but my XR will use the rears to about 50% in a rally like Idaho or Oregon Trail, but the fronts will get barely worn, so for me it is 2 new tires per event, and I rotate those fronts to the rear and put fresh tires on the front.

You don't have to run the national to enter MaxAttack! so the entry is more like $800 with notes.

So will you be at Olympus or OT then? Going to be an epic G5 battle if you do.

You, Derik Nelson in his M3, Charles Buren in his V8 Volvo, Burress, maybe more, and me of course!

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Gravel Spray
Are the 318ti's the same wheelbase as the M3/E36??

Nobody believes me when I tell them its the same, but they are. The TI uses the rear beam setup from the E30 chassis, so it's more durable for rally duty, but on the track its known to be a bit slower than the multi-link rear of the standard E36.

According to wikipedia, the wheelbase is 110". THIS IS INCORRECT - measured yesterday and it's 106". Knowing the difference between my GTX 94" and Evo 104", I'm hopeful that the BMW will feel somewhat more stable than its RWD layout would suggest.

Dave



Edited 2 time(s). Last edit at 01/29/2011 12:05AM by DaveK.

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DaveK

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Gravel Spray
Are the 318ti's the same wheelbase as the M3/E36??

Nobody believes me when I tell them its the same, but they are. The TI uses the rear beam setup from the E30 chassis, so it's more durable for rally duty, but on the track its known to be a bit slower than the multi-link rear of the standard E36.

According to wikipedia, the wheelbase is 110". Knowing the difference between my GTX 94" and Evo 104", I'm hopeful that the BMW will feel somewhat more stable than its RWD layout would suggest.

Dave

Damn 110" is long, but thats not bad at all...it's a good thing.

On your evo rally costs, you have to also factor in;

Diff rebuilds, especially the front as it's been packaged onto the transfer drum so it's very small for what it is being asked to do in a group n car much less a proper open car.

Pretty regular transfer case replacements due to the fact that from the evo 7 on up they moved the rear out put from below the sub frame to the top, so it's a hypoid run the wrong direction and has only .5 qt gearoil. I've seen the ring and pinion's turn blue.

Regular ACD pump replacements, with a good computer and map you'll be working the shit out of the pump.

Axles

Prop shaft etc etc etc.

I donn't know what kind of power you're making in the evo but I can tell you that when we went to the 10:1 stroker motor shit got real expensive real quick.

You've got to be a millionaire (like spare millions) to run a real open class car. You can have just as much and infact more fun running a 2wd car, less stress same roads, same joy.

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Gravel Spray
On your evo rally costs, you have to also factor in;

Diff rebuilds, especially the front as it's been packaged onto the transfer drum so it's very small for what it is being asked to do in a group n car much less a proper open car.

Pretty regular transfer case replacements due to the fact that from the evo 7 on up they moved the rear out put from below the sub frame to the top, so it's a hypoid run the wrong direction and has only .5 qt gearoil. I've seen the ring and pinion's turn blue.

Regular ACD pump replacements, with a good computer and map you'll be working the shit out of the pump.

Axles

Prop shaft etc etc etc.

I donn't know what kind of power you're making in the evo but I can tell you that when we went to the 10:1 stroker motor shit got real expensive real quick.

You've got to be a millionaire (like spare millions) to run a real open class car. You can have just as much and infact more fun running a 2wd car, less stress same roads, same joy.

In the 3 year's I've run the Evo, I've blown up:

1 front Cusco 1.5-way diff (now on Wavetrac - has held for 2 seasons)
1 t-case ring & pinion overheated and whining.
2 rear diffs - one Cusco 2-way and one Carbonetics 1.5-way (now running modified OEM unit)
1 fully built engine - suspected oil starvation on super super long right 5
1 custom radiator & oil cooler - popped by rod parts - see above LOL -
1 engine wiring harness - engine BBQ
2 HTA3582R turbos

I run a MoTeC MDC on the car, so have been expecting a diff pump failure, but I'm wondering if the fact that the longest my car will get beat on is ~11-12 minutes keeps it from getting worked too hard. I also haven't had much opportunity to mess with the unit, so I'm still on the maps the unit came loaded with. The local hillclimb series is all dirt, but roads are only 3-5 miles in length. Another nice thing is we use rolling starts, so that really cuts down on drivetrain shock.

I'm now running a 2.3L stroker with 11:1 compression. The engine has been tuned on an AEM for the last three seasons, running E85 fuel, we've just switched to an MoTeC M800. The car on "kill mode" makes 625hp/550tq, but with such a big turbo, it really is on the laggy side. No pansy lawyer mandated restrictors here in Colorado - the elevation and altitude gain at events is enough to slow us down. As a result I can run a bigger turbo and wind the motor out to 8k, so I'm still left with a 3000rpm power window. I will fully admit that that much power on dirt is just plain silly. We had a "hillclimb" event at the CORE facility and it was wheelspin city all the way through 4th gear...until that costly super long right 5.

Dave

And what was top speed you reached at that CORE event again Dave?

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NoCoast
And what was top speed you reached at that CORE event again Dave?

I beleive the technical name for the speed was "fast enough." LOL The next time the group went back to race there, a huge chicane was added to that straightaway, but the back straight was nearly as fast. An interesting note is that my top speeds were probably 5-10mph slower with my dual element wing...which broke on run 1 due to the rough surface. Our 2nd run felt soo much sloppier because we were running wingless and the back of the car never felt planted.

For those of you who like to run numbers, datalogs showed a smooth climb to over 7000rpm in 5th (I've swapped the US highway gear with a JDM 5th gear).

Dave

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DaveK

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NoCoast
And what was top speed you reached at that CORE event again Dave?

I beleive the technical name for the speed was "fast enough." LOL The next time the group went back to race there, a huge chicane was added to that straightaway, but the back straight was nearly as fast. An interesting note is that my top speeds were probably 5-10mph slower with my dual element wing...which broke on run 1 due to the rough surface. Our 2nd run felt soo much sloppier because we were running wingless and the back of the car never felt planted.

For those of you who like to run numbers, datalogs showed a smooth climb to over 7000rpm in 5th (I've swapped the US highway gear with a JDM 5th gear).

Dave

i don't know what that means! i just want how fast!!!

I think based on my research that means that you were going somewhere around 158 MPH?

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NoCoast
I think based on my research that means that you were going somewhere around 158 MPH?

OEM 5th gear on an IX is a 0.720, and the JDM 5th is a 0.825. Your guess is spot on for a car with a stock gearbox. Either way, its moving...especially when you're on a bumpy frontage "road" that's not quite straight, less than ~100' from oncoming traffic on I-70 that's blasting towards you.

Dave

How many years old and how bald were the tires you were running?

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NoCoast
How many years old and how bald were the tires you were running?

That's the Dave of 2004-2009. I learned my lesson on used tires when we lost to Regester by 0.03 seconds at Temple Canyon in 2009 running 10-year old 3rd or 4th hand Michelins. Hahn got them from someone in the mid-west, who gave them to Steve, who gave them to me.

The tires we ran at CORE were just 2 runs old. They only had two runs at Temple Canyon 2010 b/c the blown clutch slave on Friday morning shakedown sidelined us from practice on Saturday. I think the BFGs are 195-70-15s. After realizing that BFG makes a 215-65-15, I've switched to that simply based on the power output of the car. To bring this back to being BWM related...I will run takeoffs from the Evo on the BMW this season and may try running the narrow ones up front and the wider ones out back.

Dave

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DaveK

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NoCoast
I think based on my research that means that you were going somewhere around 158 MPH?

OEM 5th gear on an IX is a 0.720, and the JDM 5th is a 0.825. Your guess is spot on for a car with a stock gearbox. Either way, its moving...especially when you're on a bumpy frontage "road" that's not quite straight, less than ~100' from oncoming traffic on I-70 that's blasting towards you.

Dave

Yeah so 138mph.

That's fairly quick.


my Saab does 105mph. But that's on a stage with TREES



Your diff adaptors are on the way



Edited 1 time(s). Last edit at 01/24/2011 07:54PM by john vanlandingham.

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john vanlandingham
my Saab does 105mph. But that's on a stage with TREES

I goofed. The Evo VIIIs had a 0.720 and the IXs had a 0.761. We hit 7200 in 5th, so my gearing sheet shows 148. If we had crashed it out there on that straight, the car could've easily found its way onto the highway...I think I'd rather run into a tree that's moving 0mph than a truck that's moving at 80mph towards me. LOL

Thanks for getting those out John! MaxAttack! schedule for 2011 just announced. Looks like we should be breaking-in the BMW out at Olympus....crap, that's coming up quick!


Dave



Edited 1 time(s). Last edit at 01/24/2011 08:14PM by DaveK.

Dave what oil pan were you running when you lost that motor? I have seen enough motors lose the bearing on number 4 from extended right handers to feel safe running a stock pan anymore.

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Billyee
Dave what oil pan were you running when you lost that motor? I have seen enough motors lose the bearing on number 4 from extended right handers to feel safe running a stock pan anymore.

Stock pan - no modifications, figured for a car racing on dirt we wouldn't see G-loading severe enough to cause problems. Funny thing was all weekend I had been taking it as 2-straights with a little pitch in the middle. The run where the motor let go I had a much smoother run into the corner, pitched it hard and held it as one smooth arc in 4th gear.

When the new motor went in we tried using a better crank scraper, but kept having clearance issues, so we scrapped that and went back to the OEM one. I'm tempted to use the AMS/Moroso pan, but for a rally car, I don't want the pan sitting lower than the OEM one, and I'm a big fan of steel pans. With the extra pavement at PPIHC, stickier tires, and big aero, I should probably look into something a bit better for our 2011 motor.

Also, which side is #4 on? I lost the one on the passenger side...or maybe it was one in from that end.

Any recommendations?

Dave