I would like to know how this goes if you dont mind sharing.:icon_tup:

What size exhaust housing are you running?

The car I spoke of used a T6 1.32 with dual open Tial 44s and 4" exhaust. No restriction there..

What port Turblown? I have run the same turbo and power did not drop off at all.

I also run a (T6 1.32 A/R) S475 and at 9300rpm power is still climbing. this is with a half bridge port and rxparts.com intake manifold. I think the T4 back housing is holding this car back...

Large street-port. I didn't build the engine so I don't know exactly..

Thanks for sharing the numbers. The drop seems to be as per T88 I use on my car, but with less boost and less power you have made (mine is D33 with 18cm2). I was thinkng of going the BW475SX3 route as well. However, you can get different exhaust hausings for the BW475SX3, what size are you running, or what size was it on for the above dyno run?

I am running a t4 1.10 hot side and 4" exhaust. Maybe I will end up going with a larger a/r.??? Come to think of it my t88 showed the same drop at top end. I am still running the Greddy manifold, I wonder if it could have anything to do with exhaust manifold design??

At what rpm are you guys that run the 1.32 t6 housing hitting 5, 600whp mark? Is there much differnce in my hp curve vs yours? Other than the power dropping off of course.

http://www.youtube.com/watch?v=qybuIv1op-s

Turbo manifold is not the issue.

There is a restriction somewhere, be it the engine porting, fuel flow, turbine wheel/housing, or intake manifold...

I have also seen this same curve style on other engine/turbos setups.. Only ones I haven't seen it on are engines with aftermarket intake manifolds and proper fuel pumps...

I am building several cars right now with over the top setups and I am bound and determined to figure out this issue once and for all. I hope to be in the 800rwhp range..

@ 13B-RX3

what exhaust housing was it please?

As you are using the 4 barel intake, no IC, no muffler, you are not limited by other factors I would say.

I would love to see that power band on my car, but it looks not possible to me as my car is street legal.

I do not like the Greddy manifold and there for I do not run one. Even I do not like the manifold, if yours is 60mm unit, you are OK IMHO.

That is the highest RPM based engine flow I have ever seen. Torque curve is still flat at 9000RPMS. What kind of port is that?

E&J Throttle body (4bbl)
JW intake
Semi peripheral port/large street port
T6 1.32 S475.

If you like that chart you should see the new one!

Well post the SOB up :egrin:

Interesting, that is very similiar to mine even with the t6 1.32 housing. :scratch: I am running twin bosh 044 pumps so I would not think it would be a fuel problem. Seems it may have something to do with intake mani setup or porting???


13B-RX3 thanks for sharing but shit man.... I sure do feel depressed now:(

Don't feel bad seven Like Iwan said, no intercooler, no muffler, intake TB ect.... This is purely a drag car.

I don't have the sheet on this computer Just Startin. I don't think most would believe it anyway :lol::lol::lol:

I think that main culprit is pretty obvious. Peak torque before 7k rpms and peak power almost immediately after with huge drop is, I would say, typical for REW intake manifold. Its just tuned for such rpms and even very free flowing hotside won´t change natural torque curve.

I will flag you before you even post ! :lol:

As long as its below 2000whp it shoudnt be a problem:bigthumb:

nice numbers with the s475, will join the club in 2012 .

I am running the t78 greedy manifold, with the "s400" t4 75mm turbo
1.25 ar ext housing. My power also drops off at about 7k rpm. I would have to say it's
The factory manifold. I've run a best time of 9.60@147 w/ 30 psi short track , and 35 psi top end tracK. This is also with no street porting on intake, jus a 2mm ex port
I'm at the end of the "stock" port venture I really wanted to run 9.20's but it's almost impossible with my race weight of 2870lbs, I guess it's time to go on a diet:scratch:
And get this bitch to run a number!!!! Lol