I feel like I have more turbo than i do power,  maybe because i slapped on 2.8 heads (26cc) because they were the only nonwarped heads i had.   I need the 28cc heads,  if i use the 511 (28cc ) heads and had them ported, how much power would that free up with about 10 psi?  I know the heads im using are a restriction.    thanks guys,

Stock T25 turbo?

ya befinitly not getting more turbo then power... also for what its worth... some 2.8 heads are 100% identical to the 3.1s ones.... and even more so they would only affect the compression ratio.

Stock T25.  I think it runs 8.8 compression right now, but wouldnt the smaller cc restrict some of air that is being compressed therefore making less power?  I have a set of 1.6 rockers to put on too.   I know this car can be faster ...  quick questio,  i thought the computer was supposed to cut fuel at 8 psi?  I rigged up a vaccum boost controller and my stock guage is running around 10.  I can set the controller to run up to 15 but i dont want to do that.     Is this because i unpluged the stock boost controller?  The title of the car was issued Dec 31,1990 so i was wondering if it had a different chip or something.   

I have a BONE stock TGP, and every once in a while, mine will hit ~10 PSI of boost with no fuel cut or anything.  I've really only hit fuel cut with it once....

the factory bosst gague is a 100% inaccurate piece of shit.. and the top end makes no differece as i said earlier.. the headds are a minor difference (if they actually are diffferent) and the intakes are identical (minus the writing)

There is one difference in teh UIM and lower intake manifold. The hose for the PCV valve connects to the UIM on the 3.1 where as the 2.8 connects to the LIM.  You could tap and thread the lim or uim for whatever your needs are for the hose, but that is a difference.

;)

Quote from: TGed on April 07, 2007, 09:44:57 AM
There is one difference in teh UIM and lower intake manifold. The hose for the PCV valve connects to the UIM on the 3.1 where as the 2.8 connects to the LIM.  You could tap and thread the lim or uim for whatever your needs are for the hose, but that is a difference.

;)

well i have 2 different plemums for the 3.1 turbos.. one has the 2.8 style pcv and the other is the 90 + ( so my 89 tgp has a 2.8 style pcv valve connector)

Only way you'll gain anthing is by porting the exhaust ports. In the chamber..the exhaust valve is already unshrouded. Just go all out on the exhaust ports. The intake flows plenty, if anything..the intake manifold is a restriction. The exhaust ports and the intake manifold are designed with low end torque in mind. On the heads the exhaust flows 110 cfm and the intake flows about 185cfm.
But even then...the stock turbo isn't enough for this motor. Step up to a larger turbo before even pulling the heads.

What would be a better turbo?  I was offered a T28 ball bearing for a silva S15 that is internally gated.  Would that be a good start i have also been told about the T25/28 hybrid.  Hopefuly my question benifits the poster and me.

Here's my honest input on the T-28 Hybrid, since I own one.

Pros:
- spools MUCH faster
- increased speed is there and FELT
- direct bolt on

Cons:
- still a small turbo, but without any large top end modifications, you don't NEED bigger.
- price...now you will be able to get one cheaper and doing the work yourself is a plus...I paid too much.

Overall, if my turbo ever went bad, I'd park the car and do some engine work, then upgrade the turbo to a t-3 series, as well as upgrade the exhaust. With a stock setup, T-28 is plenty big. With my setup, a very decent amount of work, it's still very good.

jonny B bad

Quote from: Shifter23 on April 29, 2008, 07:13:18 PM
What would be a better turbo?  I was offered a T28 ball bearing for a silva S15 that is internally gated.  Would that be a good start i have also been told about the T25/28 hybrid.  Hopefuly my question benifits the poster and me.

Those Nissan T28's are typically going to take a good bit of work to bolt on to a TGP. I would go another route...

Quote from: mfewtrail on April 30, 2008, 01:18:15 AM

Quote from: Shifter23 on April 29, 2008, 07:13:18 PM
What would be a better turbo?  I was offered a T28 ball bearing for a silva S15 that is internally gated.  Would that be a good start i have also been told about the T25/28 hybrid.  Hopefuly my question benifits the poster and me.

Those Nissan T28's are typically going to take a good bit of work to bolt on to a TGP. I would go another route...

That's why you buy the T-28 kit and build it in your T-25 shell...thus creating the T-28 Hybrid.

Hey can someone explain what a manual boost controller does? How hard is it to upgrade the wastegate?

i like chicken