GT-ss or GT2530?

[reza168]

Hi guys,

Very happy to see the thread going out like this.

i did not like it because by 6500rpm there was nothing left and you had to change gear, alot of this was the way it was mapped and setup but did not suit my driving style. the other issue for me was it was very bad on fuel on a ong run do to being on boost so early cruising at 70 - 80 mph it was always on boost.

Ok, reading this. Does it really lose boost at 6500 rpm? Is it due to mapping or just the turbos boost limit?

If I went for the GT2530, planning to install the Tomei Poncams, gears and Reytec. Will this help quicken up the low revs and what output (bhp or whp) will I be looking at?

Thanks.

[SamuraiSam]

Dear god. Don't read AshFrancis' post. Don't listen to somebody with back-to-back hands on information. Don't listen to any of those 2530 fanbois.

/sarcasm.

AshFrancis, it's good to hear, always, about solid real-world experience like you have. Thank you for posting.

I think a good analogy to the "everyday around town car" people that like N1's, or GT-SS, or GT2860-7's, is to compare those to a stock turbo on say a Volkswagen 1.8T. The auto manufacturer in that case was not concerned about absolute performance, but more about the perception of speed and lack of "Turbo Lag!!!" for the uneducated end-user which generally has little to zero high-performance driving skills. The turbocharger (a Borg Warner K03) develops lots of boost at low revs way before the engine reaches peak VE (which is analogous to peak torque on an NA engine or depending on how you look at volumetric efficiency vs pressure ratio) but is absolutely outflowed and chokes and dies at higher revs.

The benefit is that there is quite a bit of low-end and midrange power, and the drawback is that the engine is severely limited with top-end power. N1, GT-SS, GT2860-7's, stock turbo cars will all puke-and-die at the top end of the rev range, which is the tradeoff for lower powerband performance. The example is absolutely nowhere as extreme as the K03 on the 1.8T example, but in either case, in my opinion it is an example of poor turbocharger selection. The reason is that on-boost around town performance is not one of my required attributes when selecting a turbocharger, and I think that anybody who "requires" such on their high-performance sports car, "Poor man's supercar," is an idiot (at least in that respect. Or maybe just uneducated, or needs more work on their driving skills.)

GT2530s are a good match for the RB26 because they exhibit as much midrange power as possible without choking and dying up top, and the result is much more power and more "area under the curve" when you compare torque curves from a GT-SS car to a 2530 car. Area under the curve is THE THING that matters.

reza168, to answer your question, the car will not really lose boost, but as the turbos become less efficient they will overall flow less air and fall off performance wise in the upper revs.

If you go for 2530's i'd install some Procams not Poncams. Bigger cams mean more area under the curve, even if (due to overlap, can be tuned by playing with cam gear settings) they cause the turbocharger's boost threshold to rise ever-so-slightly, the overall power gain far offsets it.

[zakiidin]

so...if i was on a strict budget plan aiming for a torquey,responsive,daily driver,aprox 450-500bhp street machine(not too bothered about top speed)...,id rather go for the bolt ons gtss with poncams/gears/strengthened belt and 600cc injector and ecu remap/new ecu...instead of going for gt2530 which needs to be accompanied by a couple more expensive goodies to get the best out of it??

[SkylineUSA]

Originally Posted by zakiidin

so...if i was on a strict budget plan aiming for a torquey,responsive,daily driver,aprox 450-500bhp street machine(not too bothered about top speed)...,id rather go for the bolt ons gtss with poncams/gears/strengthened belt and 600cc injector and ecu remap/new ecu...instead of going for gt2530 which needs to be accompanied by a couple more expensive goodies to get the best out of it??

Yes! More or less.

[SamuraiSam]

Originally Posted by zakiidin

so...if i was on a strict budget plan aiming for a torquey,responsive,daily driver,aprox 450-500bhp street machine(not too bothered about top speed)...,id rather go for the bolt ons gtss with poncams/gears/strengthened belt and 600cc injector and ecu remap/new ecu...

Yes, except as supporting mods I'd do 720cc injectors+fuel pump+new ecu+z32 MAFs. Poncams+GT-SS=win.

Originally Posted by zakiidin

instead of going for gt2530 which needs to be accompanied by a couple more expensive goodies to get the best out of it??

GT2530 does NOT need to be accompanied by anything beyond what GT-SS needs. They work great on a car with boltons, the aforementioned supporting mods, 100% stock bottom end, stock head, stock cams, stock cam gears.

[TREG]

Originally Posted by zakiidin

so...if i was on a strict budget plan aiming for a torquey,responsive,daily driver,aprox 450-500bhp street machine(not too bothered about top speed)...,id rather go for the bolt ons gtss with poncams/gears/strengthened belt and 600cc injector and ecu remap/new ecu...instead of going for gt2530 which needs to be accompanied by a couple more expensive goodies to get the best out of it??

Yes I'v got 700cc injectors on the Gtss.

[SkylineUSA]

600 are fine for GT-SS turbos.

[SamuraiSam]

600cc injectors vs 700cc injectors. I have yet to hear anybody state a fact that says 600cc is better than 700cc.

Here is some information on the subject

Injector's

Originally Posted by SamuraiSam

-Injectors. Do 720cc injectors, they cost the same as 600cc injectors. There is no downside to using too big of an injector (to a point) other than losing a bit of 'resolution' but this is not an issue with 720cc's in my experience. IMO you have stock (444cc), the next logical step is 720. The only people who will tell you otherwise want to sell you 2 sets of injectors

[SkylineUSA]

If the guy all ready has them, then he is good to go. That was my point. I never said they were better

[meorhalil]

I am putting in a GTSS in my car and would like to know if a single tomei fuel pump rated at 276 l/hr sufficient? It is rated 590PS at the tomei site. I am using a 660 cc/min injector. What should be the ideal fuel pressure setting? Would 3 bar above manifold pressure be enough for the injector in term of delta pressure for good control and flowing capacity whilst not stressing the fuel pump?

[SamuraiSam]

Originally Posted by SkylineUSA

If the guy all ready has them, then he is good to go. That was my point. I never said they were better

Understood, agreed

Originally Posted by meorhalil

I am putting in a GTSS in my car and would like to know if a single tomei fuel pump rated at 276 l/hr sufficient? It is rated 590PS at the tomei site. I am using a 660 cc/min injector. What should be the ideal fuel pressure setting? Would 3 bar above manifold pressure be enough for the injector in term of delta pressure for good control and flowing capacity whilst not stressing the fuel pump?

-A single Tomei 276lph will be wonderful for your setup.

-The ideal fuel pressure setting is stock, with a stock fuel pressure regulator and a stock fuel line. This setup will cause no issues with 'stressing' the pump.

[kismetcapitan]

yep, set the fuel pressure regulator at 3 bars with the vacuum hose disconnected. To be on the safe side though try not to make too much power over 500bhp at the crank. At 600bhp crank you need twin pumps.

Don't mess with 600cc injectors. Go with 700 or 800 - they will work just fine with just about any setup; I would even go 1000 but I think that's where idle problems come into play. I have 700cc and wish I had 800 - I have to run 4 bars base fuel pressure to flow enough fuel (injector rating varies in direct proportion to fuel pressure, so my injectors flow about 820cc/min at 4 bars).

GT-SS turbos feel damned quick. But 2530s are, in reality, faster. At 1.9 bars boost I run as fast as a Carrera GT, and that's with my grandma-shifting, losing all kinds of rpms and boost (I shift slow to take it easy with my gearbox) And who wants to be slow?

[mifn21]

If my car is pushing out 360-365 at the wheels at 1 bar can I get away with a single Nismo/Tomei pump? I'm running GT-SS with poncam B's and am hitting 95% duty on the stock injectors, but I'm ordering a set of 700cc ones this week so will be getting it mapped to 1.4bar
Would a Bosch 044 flow more? Noone can tell me what the Tomei and Nismo pumps flow at 5 bar pressure (I think the 276l/h is quoted at base pressure of 3bar)


Although after reading this thread I'm now tempted to sell em and get 2530s, damn you all!

[SamuraiSam]

Originally Posted by mifn21

If my car is pushing out 360-365 at the wheels at 1 bar can I get away with a single Nismo/Tomei pump? I'm running GT-SS with poncam B's and am hitting 95% duty on the stock injectors, but I'm ordering a set of 700cc ones this week so will be getting it mapped to 1.4bar
Would a Bosch 044 flow more? Noone can tell me what the Tomei and Nismo pumps flow at 5 bar pressure (I think the 276l/h is quoted at base pressure of 3bar)


Although after reading this thread I'm now tempted to sell em and get 2530s, damn you all!

Yes, you can get away with a single Tomei pump. I don't know about the Nismo maybe it's the same pump? I only have experience with the Tomei pump. It (along with a set of 720cc's) works great at 414whp with a pair of GT2530's and a bone stock engine on the only GT-R I've ever tuned. No fuel issues whatsoever.

A Bosch 044 would flow more. It would also be more expensive, more difficult to setup, and noisier. It would also be overkill for your setup. If you are planning on further mods and going for alot more power, it very well may be worth considering.

[TREG]

Originally Posted by mifn21

If my car is pushing out 360-365 at the wheels at 1 bar can I get away with a single Nismo/Tomei pump? I'm running GT-SS with poncam B's and am hitting 95% duty on the stock injectors, but I'm ordering a set of 700cc ones this week so will be getting it mapped to 1.4bar
Would a Bosch 044 flow more? Noone can tell me what the Tomei and Nismo pumps flow at 5 bar pressure (I think the 276l/h is quoted at base pressure of 3bar)


Although after reading this thread I'm now tempted to sell em and get 2530s, damn you all!

What type of road driving are you doing??