just curious to see/hear from those who have maxed these out with ur set up and if at all possible a graph . debating keeping mine or upgrading to 30's/35's

 

I saw someone max out one GT28S (RS non ball bearing made by tial sport) .60a/r cold
.64a/r T25 internal wastegate, it did 359WHP 350ft/lbs@27psi straight C16 on a VW 1.8L.


P.S. That is smaller than what GTM use in the STG2.

 

Twin gt28's like what comes with the APS basic kit I think maxes out a little over 500 on a dd dyno. That's fully built engine, fuel system, haltech, etc.

 

The GT28RS's with .86 A/R are pretty similar in size to the TD05H-G18's Greddy uses in their kit, and I have seen them break the 700whp!!

 

I will try to max mine out hopefully in a month. (or max out the fuel sys first)

 

Maybe on a bad day on Injected's heartbreaker DD

If you wait a couple of weeks i will be finding the limit to modified APS GT28s, on pump gas +meth and race gas.

But there is a car currently at Z1 with a sleeved (3.5L) built block with no heardwork and JWT C2 cams and APS Basic ball bearing kit with Twin GT2871s

This is on 93 pump gas w/o Meth @15psi Tuned with Osiris

 

^^ .64 or .86 a/r ? These are the exact same turbos I bought for the TT build.

 

that graph is with stock .64 housings

 

I can barely get more than 518whp 550WTQ out of the APS GT28's with 15psi@3k RPM tapering off to 13psi as the RPM go up on a DD

 

Hmm. I'm running the pair off the gtm stage 2 kit atm made 530 at 10 psi. Thought these flowed in the upper 7xx's

 

Im not sure the exact specs on the GTM GT28s but APS uses a small GT25 compressor housing and relatively undersized .64a/r turbine housing. So you can likely make more. Im not sure why people aren't getting more out of them though, i made 510 on stock block @ 11.5psi with these turbos, and Z1s dynojet consistently makes similar (in some cases lower) numbers that Forged's DD

 

Must be a bigger housing then on the gtm ones. They had a lot left in them when we were tuning.

 

Debating which direction to go with my build. Limited by the crank and clutch atm I think OS giken twin plate and the stock crank neither of which seem to gulf more than 700 stroker and new clutch are outa the question don't have the $ to fund all that so I was thinking bottom end build with a billet girdle and then springs and retainers in the head and running a twin pump for fuel

 

The stock crank would be fine for your goal. (SP did 1248whp on the stock crank and spin it to 9000RPM )

Per GTM thread :


Also, I don't remember there is a billet girdle for the HR engine since Nissan change the engine design.

 

on all of that, stock crank is fine, and no such thing as a billet girdle for an HR since its a one piece main girdle like the GTR, alot stronger than even a billet girdle


OP you need to do some more research

 

hmm interesting did not know it was 1 peice, was goign off some information from a friend of mine that i thought was correct! good news tho save me some $ ! ty

 

HR is so much better than DE... SMH

 

with a stock higher comp motor you're already making more power than somebody with ~9:1 built motor...but i do agree i'd be nice to see people making more power with them. i'll let everybody know what my pos makes once it's done, hopefully sometime this month.

 

hey be nice! I like my DE!!

 

De ftw