Another S38B36 rebuild...but different - Page 4

Nikosx · 26th August 2011, 08:18

Wait... you have shrick cams and the power falls off at 6100?

Turk · 26th August 2011, 16:51

Looking good, playbook HD will probably make it look even better (i see with my ears when it comes to engines!) Loving it. did you have it resprayed, or did you do that x-kote, or is that just some mean waxing? I was hoping to say something witty, but mostly just drooling over going to a 4L in one of our beasts, thats awesome. I agree its a little weird on the power drop at 6100rpm? i find that there is still a lot to be given from the stock above that. But I am significantly less techinical then i would like to be, so dont read too much into me chiming in to question it.

thanks for posting, great to see the project through and i totally agree with you on the stupid aircare cash grab scam, so i am glad to see you have gotten through for another year, I managed to make it through this year actually lower then last in a few of the catagories.

Luxauto · 26th August 2011, 18:45

Quote:

Originally Posted by Chunkster

Definitely, we can compare cars!

The high AFR was on the original stock engine before we rebuilt it. This is identified as Run #2. Run #1 was the rebuilt engine.
Dan went with a conservative tune after the rebuild so the AFR's are where they should be in run #1.
Everyone has a unique way of breaking in the engine after the rebuild. As long as it's done consistently and works, they will stick with this method. I'm getting the car back so I can put a little break in mileage on the car, especially before our late summer ends. The power does taper off at around 6100 rpm so I won't be going past 6500 rpm that often . Then it's heading back to Miller for some followup work that I'd like to have done.

I no longer have my 3.8, but look out for a diamanteshwarz M5 around Vancouver, sold it to a nice guy there. I was eyeing up a 66000km 3.8 on the Japan auctions this morning...

13+:1 AFRs explains how you melted a piston! Glad the current tune is more conservative, though I'm still not clear what they are (hoping they're not still in the 13s...).

Unless the new pistons are significantly heavier than the originals, your power really shouldn't be dropping off until you're well past 6000rpm, hopefully that improves with some miles and tuning. I really hope you aren't beating on it before the first oil change. Yes, there are many different break in methods, but I would find out and follow whatever BMW engineers recommended....

Chunkster · 9th October 2011, 18:36

A little update. Had the guys at Miller build up a new exhaust system for the DK. A new stainless steel 2.5” custom exhaust system from the headers back. Dual Vibrant high flow cats with a Magnaflow pre-muffler and main muffler.

At cold start, the exhaust note is low and strong. As it warms up, the low noise mellows out to a strong deep sound at idle. When you pull away and give it some throttle, especially at the higher rpms, the sound is more attune to a deep sport bike sound. The sound is awesome. I will try to post some videos of the exhaust sound as soon as the weather cooperates up here in the Northwest. For now, here are some pics….

Oh yeah, almost forgot…the dyno results…

Stroker with OEM exhaust vs Stroker with Miller exhaust:

After a quick retune, picked up 31 ft-lbs at 2900rpms! Mo torque!

And just for comparison between full stock and DK’s current build:

OEM motor and OEM exhaust vs Stroker with Miller exhaust:

Chunkster · 9th October 2011, 18:39

Here's a quick video of the Miller exhaust...

http://www.youtube.com/watch?v=Qu208LZgoCA

And another video I just uploaded that'll give you a better idea of how the engine and the new exhaust sounds.

E34 Stroker M5 drive with new Miller exhaust - YouTube

Tim in N FL · 9th October 2011, 21:47

Chunkster,
I love it...sounds great! My '91 M5 a still wears its original factory exhaust system at 186,000 miles and still sounds pretty nice, overall. I do like the sound of the Eisenmann Race and your custom system. I've been following your excellent s38b36 rebuild thread for some time now. Kudos buddy and Happy ///Motoring!
Cheers,
Tim

p.s.,
Shameless self promotion...my '91 ///M5 is For Sale...in case anyone perusing this thread may be looking.

AseanAero · 12th July 2012, 14:15

Ok , this is an old thread but from what I understand pistons tend to expand to an oval when overtemped, normally the damage occurs at 90 degree from the orientation of the piston pin

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