Thoughts on GT-SS TURBOS

[GTR032]

Where did you get the MINES dumps from and how much did you pay?

I am trying to locate some - or perhaps Tomei Dumps as I think they are similar.

I'm not convinced of the split pipe design at all.

 

Did you have to mate them to MINES front pipes? Or are most Front Pipes and Dumps interchangeable? (ie do MINES dumps match up ok with HKS Front Pipes in terms of flange and bore etc?)

I actually got the MINES dumps from ebay, there 2nd hand but apart from giving them a clean they are in great condition. Paid $340

Nah didn't have to mate them with mines front pipes. Everything bolts up fine. My total exhaust system has 3 different brands mines dumps, HKS front pipes and trust power extreme II cat back.

Would definitely recommend the GT SS KIT, comes with absolutely everything needed to bolt into the car.

[PSI_GTSII]

I was going to go for the GT-SS's from NENGUN, but instead went the Garrett GT2560R's, as they are available locally (no risk of import duty, and there under $1500ea) they are mated to Greddy / Trust Dumps and front pipes.

There is some machining required to make these fit as both the Turbo's themselves and the Dumps have extensions, so as the wastegate gasses are seperated, obviously the extension is easier to remove from the Dump pipes.....

[The Alchemist]

Dragging up an old post but heres my setup tuned on the 12 psi wastegates that come with the Gt-SS turbo kit.

257 RWKW at 12 psi on 95 octane pump gas.

The torque curve is exceptionally flat with a slightfall off when the wastegates first crack open, at 3200rpm, as I'm not using my boost controller yet they take a while to reach 12 psi, at 4200rpm.

Boost response with the throttle is instant requiring only small throttle openings to bring on the boost.

Problem with that was the surge!!!

I had the cams set on my original turbo settings of plus 2 inlet and -4 exhaust (tightening the lobe centers)but this certainly didn't work with the faster spooling GT-SS turboes. I had to widen the lobe centers back to standard setting the cams back to zero/zero to control the surge problem. I was getting surge at 50km/hr on light throttle on any gear. Sounded like a choo choo train and was really loud.

Now I have it pushed out to 100km/hr in 5th gear and almost gone in 4th gear also at 100km/hr > drivable now at least.

Will adjust the cam timing later once I've done a few miles and have some time to do more tuning.

Air flow mods include:

Tomei cams 260/260 at 9.15mm lift. HKS degree wheels.

New uprated valve springs that will allow up to 11mm lift

Major head flowing/porting job.

8.8:1 compression

Greedy turbo inlet/outlet piping kit and filter kit which eliminates the turbulance where the 2 turbo outlets , meet.

The air flow meters have been changed to 80mm RB25 AFM's as the 65mm GTR units were maxed out at 5.1V back at 230RWKW with the original turboes.

HKS Super Drager exhaust with no cat.

HKS split dumps pipes.

Plenum is standard running the standard 6 T/B's.

Exh manifold is standard.

Tuned by myself with a Power FC using FC Datalogit software.

Will post more dyno graphs showing cam timing adjustments and more boost as they come along.

Cheers,

Mike

[discopotato03]

If you think the differences between GT-SS's and 2530's is technology I can tell you this . The compressor wheels are same family though different trims and no doubt tip heights . The turbines are different types not just a trim difference . It pretty obvious that the SS's are designed to spin faster given the same mass exhaust flow than 2530's so they will make positive pressure at lower engine speed .

If I had to guess I'd say some people don't like their GTR doing the gratification thing from 4000 up so want a bit more torque in the sort of rev range wot t' good tawd ausie six pac does . They are a 1400+ Kg car with a low compression ratio 2570 cc six off boost after all .

The 2530's were designed to give little away to the std T28's but make far better mid range and top end so they are a win if you want more of the same so to speak . There is no way that GT-SS's will make ultimate 2530 power with higher boost pressure , it can't be so because their housing passages are smaller and their turbines more of a closed blade design - that which gives them earlier response goes against them at the other end of the gas flow range .

They really are horses for courses and the user needs to decide what sort of power and rev range they want to have . So whats it to be , a true grand tourer or an urban blatmobile ? Given a choise I reckon I'd use 2530's and do my damnest to tune the lower end to be the best possible . Who knows maybe those new Tomei R Poncams and goods dumps/exhaust plus a little smoothing of the head/exhaust manifolds/turbine housings plus a little more static compression may make the better overall package than just bolt on SS's . Good tuning as always critical .

Just my 2c , cheers A .

[ferni]

The 2530's were designed to give little away to the std T28's but make far better mid range and top end so they are a win if you want more of the same so to speak . There is no way that GT-SS's will make ultimate 2530 power with higher boost pressure , it can't be so because their housing passages are smaller and their turbines more of a closed blade design - that which gives them earlier response goes against them at the other end of the gas flow range .

You said it yourself, goes both ways, no way GT-SS will be able to make the same power as 2530's up top, which also goes the other way, 2530's wont ever be as responsive/come on as early as GT-SS. Both are great turbos, just need to decide what you want. I'm interested to see how the new GT-ZZ (i think?) go....

[Guest Mashrock]

I have a question now regarding dump pipes.

you all seem to be using them

what gains could i expect from using a set of split dumps?

i remember building my own exhaust for the pulsar gti-r but that included a front pipe also, this was by far the best thing i have done to a car opened it up so much,

would ui experience the same with split dumps on the gtr?

mind you i already have a nice high flowing veilside exhaust with front pipes also. but still running standard dumps..

[Guest Mashrock]

http://cgi.ebay.com.au/GTR-RB26DET-Stainle...1QQcmdZViewItem

and i figure an upgrade like this would be worth while also?

as i'm still using standrad manifolds also. or is the old story about the cast ones perfect for the job.

mind you they could have been fiddled around with in japan. as my engines been out, and aftermarket turbos been put on. and so on.

[ferni]

I'll probbaly be flamed but personally i don't think they are worth it. I still have stock dumps on mine with no problems, and no plans to change.

R31Nismoid is going to have the same setup as me soon but with those trust split dumps, so will be able to see if there is any major difference once his car is ready...

[Guest Mashrock]

yeah i figure this.

but i'd say decent aftermarket stuff would flow a lot more than the standard.

mind you i think my car is too much for me now as it is.

well i await these results. and see how it goes. i would think a bit more across the whole range. surely someone has done similar tests before.

[R31Nismoid]

Yeah, i will for the sake of testing run exactly the same setup as ferni.

I do have cams and other stuff on the agenda. But ill have a chat to Race Pace and see if we can get a comparo going.

Being our motors/turbos etc will be identical, it will be interesting to see the end result.

scared ill make more power ferni?

[ferni]

mash: yeah aftermarket stuff will probably flow more, but the question is how much, and my guess is not much more, not for the $ spent...

ash: doesn't matter how much power you make, i'll still be faster because i've got traction You can have the dyno-queen crown tho I'm sure you'll make more power than me, and i'm sure you'll be stoked with the end result, I know i am.

[GTRsean]

Me too. I'm looking at upgrading to either R34 n1s $3200 or HKS GT-SS $4200.

My aim is for a jack of all trades street car for daily driving, and the odd drag and track session.

I have the support stuff in place, nismo pump, 720cc injectors, no airflowmeters, front pipes big fmic etc.

Dump pipes would go in once the current R33 n1 turbos are taken out.

Just want to update turbos to ball bearing for more response and power.

I liked the power that the n1's put out, but my aim is for around 350+kw at the wheels with more response. So it's down to 34n1s or GT-SS. Have read the whole topic and it helps a fair bit, but I need more info on driveability in varying conditions, use.

[R31Nismoid]

GT-SS i dont think will get you to 350rwkw+

Closer to 320-330rwkw at a max. Much more than that i think is realistically out of the ballpark.

I think there was one person who pumped out 360rwkw from GT-SS, but that interestingly enough hasnt been replicated as yet by anyone as far as i know.

But that said, i will eventually have all the bells and whistles and will push the GT-SS as hard as they will go to see if i can do it on pulp aswell.

ferni - ill have the exact same setup as you for a while. Im more interested in comparing mine to yours while im in EPA mode for at least 3-4 months, and then doing extra stuff later on when i get time/money.

You might have traction, but remember im over 150kg's lighter haha

[ferni]

You might have traction, but remember im over 150kg's lighter haha

I'll take a dump before we go hehe yeah will be good to see how yours goes for comparison, but i'm stoked with how mine drives now...

[West]

Me too. I'm looking at upgrading to either R34 n1s $3200 or HKS GT-SS $4200.

My aim is for a jack of all trades street car for daily driving, and the odd drag and track session.

I have the support stuff in place, nismo pump, 720cc injectors, no airflowmeters, front pipes big fmic etc.

Dump pipes would go in once the current R33 n1 turbos are taken out.

Just want to update turbos to ball bearing for more response and power.

I liked the power that the n1's put out, but my aim is for around 350+kw at the wheels with more response. So it's down to 34n1s or GT-SS. Have read the whole topic and it helps a fair bit, but I need more info on driveability in varying conditions, use.

I thought 2530 will give you that!

[R31Nismoid]

I'll take a dump before we go hehe yeah will be good to see how yours goes for comparison, but i'm stoked with how mine drives now...

Yeah, after seeing them on a GTR, im very interested to see how a RWD application works with the RWD dynamics being totally different

[GTRsean]

"Yeah, after seeing them on a GTR, im very interested to see how a RWD application works with the RWD dynamics being totally different"

No traction, in the first few gears.

I thought that 2530's would be a little full on for my stock innards RB26, but I'll keep em in mind. How much roughly brand new for 2530's?

[R31Nismoid]

"Yeah, after seeing them on a GTR, im very interested to see how a RWD application works with the RWD dynamics being totally different"

No traction, in the first few gears.

Dunno about that

The power delivery is so liner and smooth, much smoother than my GT30/RB25 combo, if that didnt have major traction issues, i dont expect the new package with similar power to do so either

[Ronin 09]

so Ash are you going to have to mod your dump pipes, as I assume that the GT-SS has the same split cast exhaust housing as a 2860R?

[R31Nismoid]

pipes are on the motor already to go.

what you mean?