To be fair I just checked both Compressor maps for the S400's. The 71mm goes up to 60Psi for a very small portion, anywhere to the right of that (75+lbs/min) and it will overspeed immediately.... with max Flow at 40psi btw.

The 74mm goes up to 45psi with max Flow at 25psi.

I'm not sure why you want to push 50psi out of these Turbo's since max Boost doesn't equal max Flow..... but maybe I don't know what I'm talking about....

You do realise that as soon as you go anywhere outside the compressor island to the right side of the surge line, the compressor will overspeed exponentially....

And last time I checked, less max Boost was actually a good thing for Intake port velocity's during off-boost.

But if you still want to try these at 50+psi, then feel free to have them modifed to a silicon nitride BB centre cartridge here > http://www.billetturbochargers.com/

 

Why did i want to push it to 50psi?? Because i wanted to make 800+whp and still stay within my Class rules for last years nopi events.. Since that didnt work out i ran a 4294 turbo and push upwards of 55psi when necessary w/o an issue...

Yes i am aware of billetturbocharges.com.. The only Florida distributor is Big daddy performance and we happen to sponsor their supra.. If we able to get BB cartridge with the BW compressor wheel our shop evo would fly.. For now though we are running PTE 6262 @ 49psi and havent had issue making near 800whp and running 8's..

Mike

 

And how did you actually check?

 

Its common knowledge that you need about a 10% increase in CSA per 1bar of Boost, to keep peak power where you want to. Therefore off-boost port velocity suffers the higher the Boost level you require to run at a certain rpm.

Luckily for us, the ports are quite High-speed and already designed for 1.5+Bar so the effects are not as severe as they are on older Cylinder Heads.

 

So it's common and you've checked!

 

If you want one for testing Geoff let me know.

 

how about more info on the thread and build itself then going off topic as this is......

 

yes we need one to test! pm or email me

 

Emailed you.

 

So FOR THOSE OF US that are actually interested in what Mitch found with the 91-79 can we return to subject?

I am not going to deny reading all of this thread start to finish was enlightening but I see a lot of info(or disinformation depending on viewpoint) that is currently being spread on other boards.

Kurt, thank you for your technical if not brief outline of what to expect with BW from both a customer service aspect and the actual tech.

Geoff, I want to go to ***** Wonka's Turbo Factory now...I just need the golden ticket.

a1091156, While I dont know your name, your to the point and accurate SAE descriptions of flow function was not lost on me and I appreciate it. I am curious if you have ever checked the mach index on a new style 4G head?

Ted, Good as always. I look forward to the actual street test of this turbo myself since I dont drive on dynos regularly.

Mitch, Please continue with the 91-79 if you would be so kind. The 83-75 is promising so the 91 must be better.

Everyone else, I know I am a no one but if you dont have anything to contribute that directly relates to this turbo test please take it elsewhere.

 

thanks for the response, this thread went way ot, so we started a new thread here:

https://www.evolutionm.net/forums/ev...vids-dyno.html

we will probably make a new/final thread once testing is complete

 

This paper is about low speed diesel applications. I wouldn't hold it as gospel.

Not worth the $15, IMO as compared to most other SAE papers I have read, it really wasn't that through.

It's also worth mentioning, I believe one of the engineers at Full-Race did his master's thesis on exhaust manifold design. Speaking of which, Geoff, is there a way a person may be able to view the research that was performed?