MyE28.com DEV

Finally got to the dragstrip. First time on slicks since Oct 2010. Current setup just not working well. Not enough gear for the turbo/cam combo. Engine makes torque too late to effectively launch with a 293lsd. Alternated between smoking the clutch or bogging the engine. Best run was a 12.16 @ 116.85.

I am going to change diffs to a 410lsd and try one more time this year.

Are people surprised your old boxy bmw beats their "built" american car?

Scottinva wrote:Are people surprised your old boxy bmw beats their "built" american car?

I lost all 5 races.

That's a pretty drastic gearing change, why not try a 3.25 first since they're pretty easy to find?

That time/trap certainly doesn't suck if you're not a getting a good launch, btw.

Jeremy wrote:That's a pretty drastic gearing change, why not try a 3.25 first since they're pretty easy to find?

The 410 is perfect to finish the 1/4 at the top of 4th gear. You always want to finish at the top of a gear. I have a buddy loaning me a 410lsd.

I blame the BBS airdam.

Nice shots, though.

Damn, the PB turbo cam doesn't make crazy torque at low-ish rpm like the stock B35 cam? That is my favorite part of the turbo M30...tires boiling and car sideways at 3k!

Makes me re-think copying your setup.

What is your redline and what time do you plan to run?

Kyle in NO wrote:Damn, the PB turbo cam doesn't make crazy torque at low-ish rpm like the stock B35 cam? That is my favorite part of the turbo M30...tires boiling and car sideways at 3k!

Makes me re-think copying your setup.

My cam made great top end power before I advanced it. It was superior to a stock b35 or b34 cam above 5500rpm. I advanced it four degrees and lost all the top end advantage and didn't seem to gain enough bottom end to support the 293lsd. The cam seems perfect for a road course car or someone who wants a 24v type power band from a m30 but it's not the best cam for drag racing. I plan on making several changes to the car this winter and one of them is going back to a stock cam. Probably a b34. I want my 400rwtq at 3000rpm again! This cam makes 400rwtq at 3700rpm which is enough of a difference that it isn't ideal for my setup and intended use.

I want to be clear that there is nothing wrong with the cam it's just not want a personally want out of a power band.

4.10 LSD?! WOWZA! You're gonna have to do your burnouts in 3rd gear

Have you tried retarding it a couple of degrees from where it originally was?

mooseheadm5 wrote:Have you tried retarding it a couple of degrees from where it originally was?

I advanced it 4 degrees from the original location to improve drivability and move the tq curve down. That's it's current location.

In it's original location the power band was very suitable for the street. The lack of low end tq made the car more drivable and it was probably quicker on street tires as a result but once you add slicks to the equation you need ample low end tq to accelerate the car from a dead stop without bogging it.

Sounds like a fun cam unless you've got a serious hard on for the dragstrip.

T_C_D wrote:

mooseheadm5 wrote:Have you tried retarding it a couple of degrees from where it originally was?

I advanced it 4 degrees from the original location to improve drivability and move the tq curve down. That's it's current location.

In it's original location the power band was very suitable for the street. The lack of low end tq made the car more drivable and it was probably quicker on street tires as a result but once you add slicks to the equation you need ample low end tq to accelerate the car from a dead stop without bogging it.

Gotcha. I think I was thinking backwards.

T_C_D wrote:

Great shot!, flexing sidewalls on an e28 is very impressive. Looking forward to numbers once youre happy with it.

6k launch, problem solved.

T_C_D wrote:

Scottinva wrote:Are people surprised your old boxy bmw beats their "built" american car?

I lost all 5 races.

blasphemy

Good & Tight wrote:6k launch, problem solved.

Not enough clutch. Tried it.

Damn, I'm close enough to Lebanon Valley to get out and watch this happen. Todd, when are you going next/last out there, I've been meaning to take my wife to see the drags...

briansmith wrote:Damn, I'm close enough to Lebanon Valley to get out and watch this happen. Todd, when are you going next/last out there, I've been meaning to take my wife to see the drags...

In two weeks if weather permitting.

T_C_D wrote:

Good & Tight wrote:6k launch, problem solved.

Not enough clutch. Tried it.

Why not go with a multi disk clutch?

Duke wrote:

T_C_D wrote:

Good & Tight wrote:6k launch, problem solved.

Not enough clutch. Tried it.

Why not go with a multi disk clutch?

Because the clutch isn't the problem.

T_C_D wrote:Not enough clutch. Tried it.

Because the clutch isn't the problem.

Lost here?

not enough clutch to get heavy car going with 6k drop and highway gears before the turbo wakes up, problem is gearing doesn't match powerband

Duke wrote:

T_C_D wrote:Not enough clutch. Tried it.

Because the clutch isn't the problem.

Lost here?

Know what could help fatten up that low midrange torque curve to get you off the line?

A little shot of nitrous oxide.

I hear Megasquirt can give you a little shot in a specific rev range, then taper to join the main on cam torque plateau.

Jeremy wrote:Know what could help fatten up that low midrange torque curve to get you off the line?

A little shot of nitrous oxide.

I hear Megasquirt can give you a little shot in a specific rev range, then taper to join the main on cam torque plateau.

For sure but I will keep it simple and swap to a stock b34 cam over the winter when I install the fresh short block Paul built for me. That way I'll have the mountain of tq right where I like it.

Even b35 hits too late for your tastes?

Jeremy wrote:Even b35 hits too late for your tastes?

I'll be happy with this mountain again in a lighter car and a fresh built motor.

That curve looks familiar.

You never should have sold that car.

T_C_D wrote:

Good & Tight wrote:6k launch, problem solved.

Not enough clutch. Tried it.

Gear change for sure then, I think you should try the 3.73.
How tall are your tires?