Jake's Epic BMW 135i Build Thread! (5+ Years of Ownership)

[Jdesign]

Rekpoint said:

I know this question is not related. How similar are the e36 and e82 chassis? Asking for a friend.

They have the same lug pattern.

[suspenceful]

Rekpoint said:

I know this question is not related. How similar are the e36 and e82 chassis? Asking for a friend.

Having owned both, they're similar but very different. Size feels roughly the same when driving, but the E82 is taller. Other than that, just feels a lot newer. It's been a while since I've driven an E36 so I can't comment on handling characteristics.

One day I'd like to LS swap an E36.

[suspenceful]

Had a blast at the 1/4 mile drag event yesterday! Managed to take home the 6 cylinder class ($200 cash and $200 tattoo credit!)

Tough being a 6MT, and I gotta get that launch down. I didn't use 2-step because the two other times I tried using it, I snapped an axle each time. Maybe one day I’ll upgrade axles and get a transmission that doesn’t lock me out of 2nd gear. Until then I’m gonna keep enjoying the car for what it is; a great street car that can do 1/4 mile, 1/2 mile, autocross, road course and still be daily driven!

PS: Turns out this little Dragy device is pretty accurate!

 
  

My 60-130mph time at the track was about 1 second slower than on the street. Not sure if it was because of the hot weather or what (130°F IATs). Trap speed is there, but I know the car has a better ET in it.

[gilber33]

Is that a tan 240 with a carbon fiber hood next to you in that first video? Twin turbo LS swap.

[suspenceful]

gilber33 said:

Is that a tan 240 with a carbon fiber hood next to you in that first video? Twin turbo LS swap. 

Yup, it's my friend Brian's Volvo. It's single turbo.

[gilber33]

suspenceful said:

Yup, it's my friend Brian's Volvo. It's single turbo.

Haha. I know Bryan. Bought some LM reps off him once. I thought he was going to twin turbo it. Either way, it's a super clean 240.

[SteelBlue]

Slow

[Rekpoint]

*Cough* BimmerStreet tattoo *Cough*

[suspenceful]

Ran into some crazy cars in Canada!

[GunMetalGrey]

You went to Canada this time eh?

[B C]

Thats a lot of maxed out credit cards on the road at the same time!

[SteelBlue]

[ChrisO]

Scary fast stuff. Crazy that evo is running 44psi, is it over 800whp?

[GunMetalGrey]

ChrisO said:

Scary fast stuff. Crazy that evo is running 44psi, is it over 800whp?

After hearing / watching that evo I did a bit of digging. 
There was one in CO (Elevation relevance) that was on 40psi and made 830whp.
So I'm gonna go with the on in Appleton being over 800 by a good bit.

[suspenceful]

Well, this was huge news for the N54 community yesterday. We've been plagued with shift bog issues for years that no tuner has been able to figure out. The more power you add, the more noticeable the lag/bog is. It's hard to notice in videos, but very noticeable when you're in the car. It feels like the car hits a wall of bricks post-shift, then takes forever to get back into power. During a race, I lose a lot of ground during shifts.

I've tried a handful of suggested "shift bog fixes", but none of them really worked. So, when this was announced, I didn't have high expectations. I loaded it up yesterday and tried it on my way to work this morning. Well, it actually works! I had the biggest shit-eating grin on my face. The car actually responds to fast shifts and feels like it should.

The only problem... it works so good that I found my Spec Stage 3+ clutch slipping after a hard shift. It wouldn't grab at all in the next gear, just revved to the moon. Kind of disappointing considering the clutch has between 3-5k miles on it (hard miles, none-the-less). I'm sure it doesn't help that I have the drag radials on the car right now, meaning it's gripping very well. The car would never spin or chirp tire between the 1-2 shift or 2-3 shift and I'm sure it will now once I address the clutch. Other people have reported snapped axles between shifts at high power this morning. At this point, I don't care about the potential damages... the manual transmission has finally been unlocked.

[SteelBlue]

suspenceful said:

Well, this was huge news for the N54 community yesterday. We've been plagued with shift bog issues for years that no tuner has been able to figure out. The more power you add, the more noticeable the lag/bog is. It's hard to notice in videos, but very noticeable when you're in the car. It feels like the car hits a wall of bricks post-shift, then takes forever to get back into power. During a race, I lose a lot of ground during shifts.

I've tried a handful of suggested "shift bog fixes", but none of them really worked. So, when this was announced, I didn't have high expectations. I loaded it up yesterday and tried it on my way to work this morning. Well, it actually works! I had the biggest shit-eating grin on my face. The car actually responds to fast shifts and feels like it should.

The only problem... it works so good that I found my Spec Stage 3+ clutch slipping after a hard shift. It wouldn't grab at all in the next gear, just revved to the moon. Kind of disappointing considering the clutch has between 3-5k miles on it (hard miles, none-the-less). I'm sure it doesn't help that I have the drag radials on the car right now, meaning it's gripping very well. The car would never spin or chirp tire between the 1-2 shift or 2-3 shift and I'm sure it will now once I address the clutch. Other people have reported snapped axles between shifts at high power this morning. At this point, I don't care about the potential damages... the manual transmission has finally been unlocked.

I need a ride.

[GunMetalGrey]

It's cool that this finally got figured out! 

Quick thoughts on your clutch slipping thing.
Clutches work on static friction, but use kinetic friction to overload to that point, and kinetic friction has less resistance than static friction (mue). With the shift bog / slower shifts you are giving the clutch a second to lock down and become static before applying full power again. When you eliminate that buffer zone you're going to have much less time for the clutch to lock down to the flywheel and then you're throwing gobs of power through it. I know it's not the long term goal, but ease up slightly on the shift speed (especially with those tires) and I'm sure it'll hold. 

How much torque is that clutch rated for? From a quick glance it shows 670tq, which would be crank measured, and you're far above that! 
^that's assuming the stock dia flywheel though.

[suspenceful]

GunMetalGrey said:

It's cool that this finally got figured out! 

Quick thoughts on your clutch slipping thing.
Clutches work on static friction, but use kinetic friction to overload to that point, and kinetic friction has less resistance than static friction (mue). With the shift bog / slower shifts you are giving the clutch a second to lock down and become static before applying full power again. When you eliminate that buffer zone you're going to have much less time for the clutch to lock down to the flywheel and then you're throwing gobs of power through it. I know it's not the long term goal, but ease up slightly on the shift speed (especially with those tires) and I'm sure it'll hold. 

How much torque is that clutch rated for? From a quick glance it shows 670tq, which would be crank measured, and you're far above that! 
^that's assuming the stock dia flywheel though. 

I've read about other Spec Stage 3+ single turbo guys dealing with clutch slip before this shift bog fix, so I figured it wouldn't last forever. Considering almost ALL of those 3-5k miles have been low RPM dyno pulls, 1/2 mile pulls, 1/4 mile launches, Road America laps and general hooning/racing on the street... I was just waiting for it to start slipping. You're correct, it's rated at 670 crank torque and I'm at 691 to the wheels. I still have a stock diameter flywheel.

I'm thinking this winter the car will get a twin disc clutch, upgraded axles, an LSD and some bushings. Maybe a new transmission to ditch my 1-2 syncho issue. Should have no problem running 10s next year...

[GunMetalGrey]

suspenceful said:

I've read about other Spec Stage 3+ single turbo guys dealing with clutch slip before this shift bog fix, so I figured it wouldn't last forever. Considering almost ALL of those 3-5k miles have been low RPM dyno pulls, 1/2 mile pulls, 1/4 mile launches, Road America laps and general hooning/racing on the street... I was just waiting for it to start slipping. You're correct, it's rated at 670 crank torque and I'm at 691 to the wheels. I still have a stock diameter flywheel.

I'm thinking this winter the car will get a twin disc clutch, upgraded axles, an LSD and some bushings. Maybe a new transmission to ditch my 1-2 syncho issue. Should have no problem running 10s next year...

I'm actually impressed that it's holding 690 at the wheels then, only being rated for 670 crank. With a 15% drivetrain loss it means that clutch is withstanding about 770 ft/lbs of torque, or 15% more than rated. 

Are larger dia. flywheels an option? I don't know if they were specific issues to the application, but I've heard that twin discs don't last long at all.

[suspenceful]

GunMetalGrey said:

I'm actually impressed that it's holding 690 at the wheels then, only being rated for 670 crank. With a 15% drivetrain loss it means that clutch is withstanding about 770 ft/lbs of torque, or 15% more than rated. 

Are larger dia. flywheels an option? I don't know if they were specific issues to the application, but I've heard that twin discs don't last long at all. 

I haven't heard of larger flywheels for N54. A lot of people use twin discs are this power level though because there aren't a lot of proven clutch options out there. I'm not looking to get a Spec Stage 5 because I read the driveability sucks.