MyE28.com

a US M30?? Has anyone run/gotten 20psi yet? Anybody tried it? Just curious.

I did some work on a RUF Porsche 911 that made ~29psi running a K27. The car scared me to death. I think it was a 3.2L. It may have been a 3.5 though.

When I get the Motec on the car and tuned, I'll attempt it I guess. We'll see.

I got my Motec ECU to talk to my laptop tonight! I reverse-engineered the proprietary com cable that they want you to buy for $125 ~0 . I made it for $10 . It was just a TTL to 232 conversion. Very easy once I figured out which pins did what on the Motec ECU. They do their best to hide that stuff in the documentation. Now I just need to find the time to build/convert the harness over and I'm good to go. I'm also building a water to air intercooler with some surplus jet engine parts I have. Should be an interesting setup when I'm all done.

Another K27er huh? Welcome!
I've only seen the 745i junkies boost to about 20psi of boost. I don't recall ever reading about anymore. Though there have been claims for 400+ HP on some 745i's - I haven't seen any dynos or any details to prove it. The K27's are pretty big (i'm sure you found that out with the lag) - and I think they can take up to 25psi or a little more before it becomes inefficient... I can't remember the results from that compressor map.

There is a gentleman by the name of JStein over on the RF board that has his 745i running 21 psi regularly. Seems his car has been doing this for quite a while now. Last known milage on his ride was at 275K miles. Last time I met him he said he could not drive the car in the wet due to the high boost and the 3,91 rear end. He drives his M6 instead, some of us should be so lucky. He also stated he has no problems spinning the tires in third gear. I also drove a 745i with 15 psi on my way back to the Atlanta airport and that car had me giggling all the way.

I am sure higher PSI is possible with the K27 and M30/M106. It would just take more effort and more money than what a more modern system (TCD) could do for less.

You can see JSteins car over at www.745i.com.

Most run the K27 at 15psi or less. Just a few over that. Most dynos with the be in the 250-300whp range. I have a few dynos on my desktop, I'll have to take a look later.

Yes, the K27 is a very large turbo. Thats why BMW used it in the first place. Putting that large a unit would minimize turbo surge comming onto peak torque. Thats my story.

RussC

I can't afford to run boost that high.

However I do know than another John -- Jon Jacobs lost the headgasket at 21 psi.

He rebuilt the motor with o rings, but very sadly, I think the car was recently destroyed in New Orleans.

the bigger the turbo the less heat...as corky said dont send a child to do a mans job =]

[QUOTE="bahnstormer"]the bigger the turbo the less heat...as corky said dont send a child to do a mans job =][/QUOTE]

Efficeincy dictates heat not size. Read the book again.
Todd