Help Me Decide Which Turbos For A Street/track Setup Gtr

[BoostdR]

our car easily made 450AWKW at all fours on BP98 @ 20psi with GT-RS's. 2.6ltr as well and was only ran in the day before this dyno run. Not as responsive as Racepace's much touted RB29 but with your extra capacity i think you would go the 'pepsi challenge' with it. Our car also made around 470AWKW at all fours on 25psi and over 500AWKW on Sunoco fuel. Look at the mid-range difference...thats where you RPM rage will be on the circuit. GT-RS's are a great turbo choice for your application...what tracks will you be racing on?

link to thread..

http://www.skylinesaustralia.com/forums/Rb....html&st=40

That is some very nice mid range indeed.... over taking the mid range of the 2530's in most ranges aswell. I recall your setup making minimal power increase intially after changing from the GT2530's? The GT-RS's are aboviously after a different setup engine...can you shed some light for us embarking on the initial voyage.?

At this stage I will be just at Mallala. Then I'll venture out from there

[BoostdR]

Interesting again that one, many a car has made 380rwkw on stock manifolds here and for many years its been done, even more so on some setups (and fuel etc).

hmm.

unique1 - if 450rwhp is your goal, GT-SS/-7 will do it... but it'll virtually make boost on idle with the extra capacity as they spool early enough on my 2.6ltr thats choked up.

Gav - that graph still amazes me everytime i see it with the smaller puppies on there and a stroker - love it

Sorry, i'll confirm for the sloower individuals. When I said "they make 350rwkw on the std cast manifolds"...I mean the two -5 turbo's on my car on my dyno....was pointing out that the stainless manifolds flow more and the cast ones can be made to be just as good if not better. Obviously others will make more and less power and have there output measured on many different dyno's with many different ramp rates with many different correction factors, with many different rolling diameters, etc

Those guys who posted up lap times in there signature block are giving me a better indication on what works. There is a few corners at Mallala that I get caught low in the rpm range---so I can see why -5s on an Rb28 or Rb30 would be a wise setup for a tight track.

Thanks for the constructive replies from those that gave them so far.

[Bumblebee]

has everyone forgotten about Toogle??...

502awkw... 9.997sec 1/4... GT-RS turbos....

they pack a pretty impressive punch and theyre responsive as

[Gav]

Thanks for the info, what capacity engine was the dyno graph comlpeted on?

So you are currently making 534rwhp with the -5s on a 2.8ltr?

Just finished a new tune and am making spot on 550 rwhp on a 2.8L. The dynograph was the same engine, except the older "peakier" setup was with GT-RS terbs, 136mm intercooler and Greddy plenum. New setup is with -5 terbs, 100mm HKS cooler and Nismo plenum. Cams are 272 Step 2 and head is extensively ported with 1mm O/S valves

[R31Nismoid]

Sorry, i'll confirm for the sloower individuals. When I said "they make 350rwkw on the std cast manifolds"...I mean the two -5 turbo's on my car on my dyno....was pointing out that the stainless manifolds flow more and the cast ones can be made to be just as good if not better. Obviously others will make more and less power and have there output measured on many different dyno's with many different ramp rates with many different correction factors, with many different rolling diameters, etc

Either/or, manifolds for the -5s is a waste, so is porting them

[Swiper the Fox]

has everyone forgotten about Toogle??...

502awkw... 9.997sec 1/4... GT-RS turbos....

they pack a pretty impressive punch and theyre responsive as

thats Twoogle....

9.95sec....

but yes very responsive indeed!...they were even better with race fuel and more boost...ill miss the GT-RS's...but they served the purpose they were bought for.

Ive put a 1100hp single turbo on it now (modified HKS T51R SPL BB)....

[BoostdR]

Either/or, manifolds for the -5s is a waste, so is porting them

Mate haven't you got something better to do.

I made 30 more rwkw with stainless manifolds and match ported turbine housings and no loss what so ever in the bottom end. If you think thats a waste thats fine. It's my engine. I'm sure others would have differing results...but I couldn't care less.

[BoostdR]

Just finished a new tune and am making spot on 550 rwhp on a 2.8L. The dynograph was the same engine, except the older "peakier" setup was with GT-RS terbs, 136mm intercooler and Greddy plenum. New setup is with -5 terbs, 100mm HKS cooler and Nismo plenum. Cams are 272 Step 2 and head is extensively ported with 1mm O/S valves

That is very very impressive indeed! I think I'll hold onto my -5's and back to back them on the engine dyno =) I have a JUN plenum to go on...will see how that goes....also trying the new Tomei dump pipes over my current HKS ones. What are your thoughts on porting the head? We have been looking at some work in the intake bowl area and short turns but minimal oversizing of the exhaust to aid port velocity.

[Gav]

I would have thought the large volume of the Jun plenum is more suited to outright hp (i.e. large flow and boost) rather than response of two small compressors. Have never seen a before and after dyno with one fitted, so I may stand corrected.

I swapped away from the cross piped HKS manifolds to Tomei items. Very nice build quality and enabled me to refit the factory heat shield and water lines. Besides neatening up the area, it drops the temperature down in this region of the engine bay considerably.

The main reason I ported the head was that I bought a brand new head from Nissan and was amazed at how inconsistent the port sizes and shapes were for a brand new item. Actually, if you think about it it really is probably an assembly line worked just tidying up the casting dags etc. I thought that whilst I was going to the trouble of doing that, it would be worth spending the extra time in port matching to the inlet (Nismo) and exhaust (Tomei) manifolds. Then, whilst we were there we fitted new guides, and may as well get bigger valves............well, you know how it goes.

So what has all this done to the result? My belief is that it enables the peak torque curve to stay flatter up the top for longer. In other words, it extends usable rev range and gives greater gear choice for most situations.

Now....if you were asking about "bang for buck'' then that's another matter. I reckon you can achieve 80% plus of what I have done with standard plenum, cast manifolds, cams and intercooler.

[Lithium]

but yes very responsive indeed!...they were even better with race fuel and more boost...ill miss the GT-RS's...but they served the purpose they were bought for.

Ive put a 1100hp single turbo on it now (modified HKS T51R SPL BB)....

Yay Congrats on the move to a big single

I thought you said when you first got the GTRSs they were quite laggy?

[Swiper the Fox]

Yay Congrats on the move to a big single

I thought you said when you first got the GTRSs they were quite laggy?

They were...it smashed a 1000rpm 'hole' in my torque curve...but that engine was built to suit 2530's. So i pulled the engine and built one around the turbo's. The result was so good it shocked even the most experienced GTR tuner/builder in Aust.(Jim Souvas at CRD) who always questioned my decision to stay with the 'low mounts'. They were simply devastating in all rpm ranges once full tune and race fuel was added (dyno graph earlier was BP98 and a simple fairly rich run-in tune)...id put that combo up against any low mount 2.6 in the world.

Gav your spot on about the porting mate...our torque curve looked like an NA V8's...flat from 4500rpm all the way to redline.

Edited July 21, 2008 by DiRTgarage

[Lithium]

They were...it smashed a 1000rpm 'hole' in my torque curve...but that engine was built to suit 2530's. So i pulled the engine and built one around the turbo's. The result was so good it shocked even the most experienced GTR tuner/builder in Aust.(Jim Souvas at CRD) who always questioned my decision to stay with the 'low mounts'. They were simply devastating in all rpm ranges once full tune and race fuel was added (dyno graph earlier was BP98 and a simple fairly rich run-in tune)...id put that combo up against any low mount 2.6 in the world.

Excellent - yeah really illustrates how matching a turbo spec and engine spec matters. Look forward to seeing how it goes with the T51R

[thirty two]

PS. on the subject of manifolds, we flow tested a chinese stainless manifold and std cast manifold and the stainless flowed 50% more! Then we spent 6 hours porting the std cast manifolds paying particular attention to the short turns and they flowed 46% more(4% less than the ebay ones). With the relability and heat retension properties of cast I know what I'll be using

Matt

Interested in porting my standard GTR exhaust manifolds also, seems easy to do at each end but how did you clean out the bit in the middle with all those bends?

I have heard of an abrasive paste that is applied and then blasted out that removes a fair bit, has anyone else come across this?

Cheers,

Rod.

[Swiper the Fox]

PS. on the subject of manifolds, we flow tested a chinese stainless manifold and std cast manifold and the stainless flowed 50% more! Then we spent 6 hours porting the std cast manifolds paying particular attention to the short turns and they flowed 46% more(4% less than the ebay ones). With the relability and heat retension properties of cast I know what I'll be using

Matt

Interested in porting my standard GTR exhaust manifolds also, seems easy to do at each end but how did you clean out the bit in the middle with all those bends?

I have heard of an abrasive paste that is applied and then blasted out that removes a fair bit, has anyone else come across this?

Cheers,

Rod.

Yes Rod, extrude honing the STD manifolds works very well. If i went back to lowies thats what i would do for manifolds...port matched extrude honed STD items with hi temp black ceramic coating for further heat retention..

[STATUS]

I would have thought the large volume of the Jun plenum is more suited to outright hp (i.e. large flow and boost) rather than response of two small compressors. Have never seen a before and after dyno with one fitted, so I may stand corrected.

yeah agreed, i was speaking to *&^% the D1gp and SUPER LAP blitz mechanic who is a JUN freak (for engine internals) and they tried all inlet manifold combinations on nomukens R34 which is a 580ps nismo 2.8l kitted rb25 with NEO head and GTR individual throttle bodies and it was the nismo inlet plenum that came up trumps. I would seriously consider the nismo item. He was the legend who built my exhaust manifold for me.

[BoostdR]

I agree the nismo collector works very well, however is may not be as well suited to 800hp....how much average power difference I would like to know.....

The Nismo intake collector is designed with form & function in mind, and is fully optimized for air flow in tuning the GT-R engine (400ps to 600ps). This intake collector is a standard item in the NISMO Z-tune GT_R34 Ver.2002. It is completely bolt-on installation, and no modifications on are necessary on the idling control, fuel piping, clutch piping & vacuum piping. (The only minor adjustments needed are on the throttle linkage & throttle sensor). Improved medium speed torque is achieved by improving airflow onto each cylinder, and this is done by refining the diameter & length of the inlet pipe & cross section of the intake collector.

Normal Collector

Based on factory item with respect to form factor, air is not evenly distributed to all 6 cylinders. As a result, the NISMO air collector tried to distribute air flow evenly & equally by redefining the intake form factor.

There is a difference in turbine inlet exhaust gas temperature between the front & the rear. The overall temperature difference has been reduced drastically due to an improved & efficient intake quantity between the cylinders on both sides. (The exhaust gas temperatures at the front-rear turbine was reduced at an average of 18% at 2400 RPM to 7000 RPM)

The fuel supply density is high in order to protect the turbocharger from high exhaust gas temperatures. With the NISMO air collector, temperatures are reduced and this resulted in improved fuel economy & improved output. Both cylinders & ignition timing could be optimized because exhaust gas temperature differences becomes small. (At 4800 RPM to 7600 RPM, output improved by an average of 1.8%, and fuel consumption improved by an average of 0.4%)

[Piggaz]

^^^^^

Group buy anyone?

[9krpm]

who is or will be tuning your car boostdR?

[BoostdR]

My engine will be tuned on an engine dyno. The tunner is not from the commercial/retail circuit.

[9krpm]

My engine will be tuned on an engine dyno. The tunner is not from the commercial/retail circuit.

Nice! It wouldn't be too hard to change turbo if the GTRS is restrictive.

IMHO the T517Z is a bit restrictive at top end in your setup.

Please post up a dyno result when you are done

Edited August 4, 2008 by 9krpm