which of these two turbos is bigger? and which one would be the better way to go for a 3.1L v6?

 

A t25 is smaller. t3 is bigger.

The t25 will spool faster, but it deppends of what car your getting it off or if your just buying a new one from some place.

I would perfer getting the t25 for a v6 but you dont always have to depend on the size of the turbo. If you are loosing boost and spike then it is a waist of money to put in a turbo. Remember stay RICH, not good to be leen with a turbo car.

-Eric

 

The T25 also known as the "T to small" because of the cars it comes in.
I think the T25's are only good for 250-270hp if I remember right, I would have to see a compressor map to know for sure, that would only get you about 10psi on a stock like engine.
That T25 would start boosting real quick, but you would be pushing it to 100% of it's capacity all the time.
I think the T3 would be better, it would take a little longer to spool (2500-3000) but it could give you more power on the high end.
A lot of the guys runing turbos on ther 3.4L's over on the camaroV6.com board all have T04B's in the 46 trim.
And with that T04 they start boosting around 3000.

 

I recommend a T3. I have a JY .42/.48 AR T3 off of a Saab on my 89 Cavalier with a 2.8- it spools completely by 2500RPM, and is set to produce 6PSI boost. Could probably put out more than that, but I don't want to blow the original 174K engine! It is my daily driver, so it must stay relaible. These T3s can be had well under $200 on eBay, in decent shape, plus it is a very popular frame, so flanges and other parts will be easy to find. I always thought it would be cool to turbo a V6 in a Camaro, but I don't own one so I never tried it. Good luck with your system.

 

FWIW
I should mention that my Cavalier turbo sytem is a remote type, with the turbo in the rear, in place of the muffler (similar to STS turbo sysytems). It works quite well, and is easy to install. The oiling system is the most complex part. While mounting the turbo that far back definitly looses some effeciency, it really sounds great because the turbine outlet is so close to the tailpipe (there is no muffler). There is no mistaking that turbine whistle!

 

What are you using for an oil pump for the return?

 

havent planned for that yet? ive heard the gravity works haha. but otherwise ive got to think sumthin up.

 

I was asking 89JYturbo how he did it on his Cavalier

 

I'm using a SHURflo 8000 series pump purchased from a local farm supply store (1.8gph diaphragm type). It is not waterproof so it is mounted in the trunk. It works great, but I just checked SHURflo's web site and they spec the maximum fluid temp at 180°F. Turbo oil outlet temps go over 230°F under load, so I hope to come up with a higher temp rated pump soon, even though this one has been doing fine. I did add a heat sink to the motor, but the that doesn't help the diaphragm handle the temps.

The oiling system was the hardest part of my remote mount system. I tried two pumps (a Carter electric gas pump and a GM 6.5 diesel lift pump) and they didn't flow enough and would cause a severe smoking problem when I pushed it hard. There was actually an oil mist on my back bumper! But this SHURflo pump hasn't given any problems in a month of daily driving (I drive a 1hr round trip to work every day).

I will post some pics of my Cavalier system soon. It's not an F-Body, but I feel it is useful info for the power adder group.

 

As far as the T25, that's the stock turbo on my Saab 9000 with the 2.3 liter 4 cylinder engine, and it's small for that, so for your V6 .... draw your own conlusion.

 

the best use of a T25 turbo I have seen was in the late 80's pontiac turbo sunbirds with the 1.9 liter isuzu 4 cylinders. hondas eat your heart out.

 

i would look at a stock GN t3, you can get those pretty reasonable price (msg me if interested in one) and it definately wouldnt be too small like you would run inot with the T25, BTW the t25 is too small on the stock 2G DSMs let alone any 6...
thatsjust my $.02

*eric*

 

i have a t3 off my friends volvo. hes juss gunna give it to me its all in good condition so that sounds like the way to go.