I always ran 15-15.5 psi....I have seen the difference on the dyno...The stock cat is good for 14 psi then becomes restrictive...this is cat vs cat...Now a midpipe will help you build hp from 4000 rpms on, below you lose hp...it's a trade off. You also will be using a lot of liquid glass on the back of your car to remove the soot (hydro carbons)...

http://www.efini.net/hpcomparo.htm

Also, I have yet to see a set of M2 BB or pettit or BNR twins outflow the stockers at higher boost. (manifold design restrictions) So far the dynos I have seen all have born this out....including the set I had..One of the guys around here is going with the BNR's so I'll dyno them but it will be in the spring...

BTW: The turbos on Brook's car were the Pettit upgrades...362.5 rwhp @ 14 psi same as a stock set does.

 

pettit flat out told me that I would not see any different numbers with thier turbos over the stock ones...they were who convinced me to go single or go m2.

I'll bet the reason you havent seen the power gains you mentioned is because you have not seen a dyno sheet for the m2 or bnr set. right??

if you have access to the m2 set's dyno sheets Id love to see them.

heresay is not experience. I have them...I would know how the power gains are.

how can you compare "high boost"? the m2 set has larger wheels and more flow...and thus at fifteen lbs is pushing more than the stock set at 15lbs..right?? how would this not make more power??? the stock manifold restricts peak...but at 16lbs the m2s are not feeling restricted AT ALL...and neither are the stockers...too bad the stockers are burnt up by then.

It sure is interesting that you can run 15.5lbs on a stock yet I can hit about 14.7 or so on the m2 set. I wonder what peak boost is on a clean cat on stock turbos. anyone run higher than that with a cat?

that will give me an idea on the flow difference between the stock and m2 set...should be considerable because of the .52 vs .59 wheel diameter difference.

as far as performance....

the stockers are frying and cooking at 14-15lbs....sure you can get one run out of them at 17lbs...but the m2 set just wakes up at 15lbs and by 17lbs they are screaming

no stockers can handle that amount of boost and make it for long...the m2 set can as their efficiency range is much higher.

My car is MUCH faster throughout the powerband than with stock turbos...ask goracer and anyone else who has seen them in action.

the stock manifold is good for at least 400-450hp....m2 actually sells two different sets of their turbos that are good for those kinds of numbers...both are gt30s but there are two different wheel sizes....I didnt find out that I could get larger wheels until I purchased them and am considering upgrading to the even larger wheel as well.

at sixteen lbs I cant keep my tires on the ground...I ran fifteen on my stockers back in the day and would only long chirp in second gear at hard shift...a hard shift with the m2s and my backend swishes all over the place.


I have been trying to get dyno numbers...will get them soon money permitting...if you have access to some I WOULD LOVE TO SEE THEM.


I will dyno as soon as i can...my gf has been out of work for four months and that put a damper on my car spending....soon I hope.





j