PT70 Compressor map

[d90dan]

Does anyone have a copy?

 

[Blazer406]

Here is one for a T70..... ought to be fairly close....

 

[d90dan]

Thanks!

 

[RUQWKNF]

Here's another one.....

Garretts GT Technology.

It really depends on who the turbo is made by as there are currently 3 different 70mm compressor wheels out there.
T-netics, Garrett and Borg Warner come to mind.
This map above is from Garretts website. This is the wheel that comes in the GT4294 turbo.
TurboByGarrett.com - Catalog


Inducer 70.3mm
Exducer 94.0mm
Trim 56

Hope this helps.

Patrick

 

[d90dan]

Patrick,
The GT4294 is one of the turbos I am looking at. It does appear the 42 version would make similar power at a lower boost setting then my current turbo.
Any thoughts on the GT4094? It would be nice to stay with the smaller frame. I've seen a 4088 on a TB and it spools RIGHT NOW.
What I'm looking for is a BB turbo with similar HP potential as my current 70 p-trim, but in BB and a ported shroud.
I know the simple thing would be a 70GTQ BB, but I'm looking at all my options.

Thanks!

 

[RUQWKNF]

In some applications, the Ported Shroud showed lower hp results than the non ported shroud. This would no doubt be due to the fact some some of the incoming air flow is recirculated into a continuing loop under WOT conditions through the port shroud. With that said, a ported shroud version of a 70 GT-Qs power might be very close to the power that you currently have. I've heard as much as 10-15 hp lost on ps vs non ps covers.
With regards to the GT4094, I never really heard any positive feedback on that turbo on a Buick application. You are talking about putting this on a Buick V6 right?

 

[d90dan]

Interesting comment on the ported shroud.
They reason I would like one is to keep then turbo spooled when you have to get in/out the throttle quickly. I believe a BOV would also work, and if the PS is a 10-15hp loss, maybe a better solution?
Have you heard any negative feedback on the GT4094? BTW, this is for a buick v6.

 

[RUQWKNF]

No negative either. I never spec'd one for a Buick 3-bolt application. I'm not even sure if PTE even offers a 3-bolt housing for that turbo. Last I heard was that the only GT series that they make a 3-bolt housing for is the GT3255A and GT3255E. I know ATP and others do not offer Buick 3-bolt specific housings for that turbo either. The GT series turbine housings bolt up differently to the chra than the standard T3 and T4 series chras do. They use 4 bolts vs 6.

The ported shroud will help keep the turbo spooled up between shifts better than a b/o valve will. Now, if you combined a ported shroud with a recirculation valve, that might really help keep it spooled. A recirculation valve would vent the pressurized air inside the intercooler plumbing back into the MAF pipe, then back into the inlet of the turbo. Vs a B/O valve would simply vent the pressurized air out to the atmosphere.

Keeping the turbo spooled up between shifts, is really only a problem on manual transmission equipped vehicles. Automatics typically don't loose more than 1psi between shifts, unless you are running a Super Uber huge turbo.

Patrick

 

[d90dan]

If I went with the GT series I had planned on getting away from the three bolt housing all together, modding/making the downpipe and header.

Recently I have needed to get completely off, then back on, the throttle when at high boost. What I found is some turbo lag before it gets back up to full boost. That's one of the things I'm looking to improve with my next turbo setup. A recirculation valve would be great (no annoying "pissst"), but I don't run any kind of intake ducting.

At WOT I have zero PSI drop on the shifts, just looking to improve spool up in the above mentioned situation.

I plan on running a mid 10 second class this year, so maybe a slight HP drop from the P.S. doesn't really matter.

Thanks for your input! It is appreciated.