I'm looking for some turbo advice. I have done some compressor and turbine map calculations for the GT40088R, GT4088, GT4082 (is this even available with a T4 turbine housing), and GT35R with T4 turbine housing. They're all VERY similar. All of them seem like they would work well for my application. The turbine sizes vary significantly (as do the turbine flow maps). The 1.06 a/r T3 turbine housing for the GT35R and smaller a/r GT4088(R) housings seem to have roughly the correct flowrates. Any insight into spool comparisons and power potential would be great. I'm trying to figure out how they all compare and which would work best for me.

I'm running a 3.4L DOHC V6 (6750 rpm redline). It is currently setup with a tangential T4 turbine housing and a 60 trim T04E compressor. I don't remember the trim or a/r on the turbine housing (either 0.58 or 0.68 IIRC). It can spool early in 3rd or 4th gear (<3000 rpm), but in first usually doesn't hit full boost until 4500 rpm +. The turbo lag I have now is completely acceptable. It helps me hook up in first gear and keeps me right in the powerband after that. Whichever turbo I run, I would like to break 400 whp with under 15 psi. Max boost would be 20 psi (VERY rarely). Daily boost would be 10-15 psi. I'd like to have the potential to break 500 whp. The torque converter is a 3000 rpm stall speed converter (it usually keeps everything around 4500-5000 rpm once the turbo spools). The turbo piping will be rebuilt for the new turbo. A divided housing is possible and could be used to separate the front and rear heads.

My goal is to have a dyno chart that looks like my current one below 5000 rpm, but without torque dropping off and horsepower staying constant. I would like to have horsepower increase and torque stay constant. This is a daily driven street car and I would like for it to remain as such. Anyway, here's the current dyno compared with a stock dyno.


I've searched on the net and found three useful comparisons (a 99 3.8L V6 mustang with the GT4088R, a 4th gen Maxima 3.0L V6 with a T4 GT35R, and Tony the Tiger's GT4088R 3.0L Camry). However, these really don't give me a solid comparison of these turbos or enough to extrapolate performance on my own motor. I know on Honda's, there is roughly a 500 rpm spool difference between the GT35R and GT40R. I'm assuming this would hold true with larger engines also though maybe not when comparing a T4 GT35R to a GT40R.

Sorry if this post was a bit disjointed. Any help you can give would be greatly appreciated.

Tim


Modified by timg at 7:01 PM 3/20/2006

 

Bump

 

Any kind of head work or cams done to the engine?

 

Stock heads and stock cams. The cam timing is infinitely adjustable (stock). The cams have roughly 0.370" lift, 205 intake and 210 exhaust duration for 0.050" lift (221.8 intake and 226.2 seat to seat). 4 degrees of overlap @ stock timing.

I'll post pictures of the stock heads in a few mintues. The exhaust ports are 1.25" tall and 2.69" wide. They're HUGE... I have flow #'s from the earlier MY heads, but the later ones are significantly improved.

Tim

 

Here they are. The head on the left is the one I will be using (96-97 MY). The head on the right is the one I'm using now (94-95 MY). That's the reason why I'll have to redo all of the piping.

Tim

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by timg &raquo;</TD></TR><TR><TD CLASS="quote">
and Tony the Tiger's GT4088R 3.0L Maxima).
</TD></TR></TABLE>

It's a 3.0L V6 Camry

 

Whoops... I knew that. Fixed!

Tim

 

Bump... I know the GT35R would work well, but is the smaller turbine housing going to limit me? The turbine side is smaller than what I'm running right now though I believe that it may still flow more. Any suggestions on turbo choice?

Tim