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i would invest in some 260 deg cams (nothing too wild) get new high flow airfilters and a good 2nd hand intercooler.

The combination of the above 3 could result in your lack of power (around 100hp) and i would think it is spread over the 3 items personally, but it could be the airfilters on their own if they are not very good
 

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there is something seriously wrong if it is only making 480bhp at 1.6bar..even with standard cams it should make closer to 550bhp at this boost.Mine made 472bhp at fly(DYNAPACK) on 2860-5s at 1.1 bar on a standard engine with std pump and injectors..i do run a tomei adjustable reg hks intercooler kit with hardpipes,nismo afms and hks intakes..i would start with changing your intercooler and pipes and your air intakes..and check your ignition timing.As regards what fueling upgrades are needed to run 600bhp at fly safely im not 100 percent sure.Im fitting a fully forged engne to my car next week and i have been advised to run 1 hks/tomei 280l/ph intank pump,720cc or bigger injectors,and a good fuel pres regulater which i already have.I think 2 pumps are unnessesary for this power.As regards the rail the standard nissan rail is more than up to the job..Keith cowies R32 runs a standard rail in hes monster r32.his is just modified to RB spec.Apparently the std rail has a bigger capacity than the hks rail!!Im not sure about uprated fuel lines for this power..should i upgrade these or would it just be a waste of very precious cash??
 

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1 tomei pump can not flow enough fuel on the GTR at high enough pressure to match 1.6bar at 600hp, it tails off on pressure at 550hp upwards, it can run at 280lt/hr but not at the required 4+ bar pressure when its at the 600 limit.

It the pressure that it cant match at the required flow rates, if you are only running low boost you can get away with it.


2 intank pumps will feed both ends of a rail and stay quiet and not smell of fuel so that was the way i went.
 

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the lack of cams in there wouldnt make a great deal of difference to absolute power, it would just shift the power band round a bit.

Adam, you have a swirl and external pump(s) do you not? if so then the fuel supply shouldnt be an issue unless you are using an aftermarket reg thats set too low.

The intercooler may hold it back a touch but they are efficient enough to flow 600 without issue as far as im aware. Air filters might be a bit crud sure, but it could be worth a pop in that case to remove them (stick some mesh over the intakes) and try it again.....if all of a sudden youve got power then thats your issue....cant see them robbing you over the best part of 100bhp though.
 

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Discussion Starter #68
but add the sum of all weak parts up and maybe...

Filters -
FMIC -
Turbo Elbows -

How restrictive are the standard turbo elbows? Thats the only restriction I can see on the exhaust side.... unless there are dead rats in the downpipes or something :O

I've given the tuner this link - see if he comes back with some more advice. In the meantime I'm happy enough to use it and work on finding my missing ponies as and when :)

Might be an idea to get Fee onto the 1/4mile and see what it runs... no real science behind it, just interested in term speeds. Whats a 'normal' terminal speed for a 480bhp (say 500bhp) GTR to run?

Fueling - Yup, good for 800 or so bhp I think.
 

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i have stock elbows on my car dude and stock manifolds (unported), so no issue there.

when my car had 525 at the fly at 1.2 bar on 2540s i hit a terminal of 123, however your car should be at least 100kgs lighter than mine was at the time especially with fee driving!!! so id expect you could hit 125/6?
 

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me? me? what's going on? ;)

What are Bosch 910s rated to? Not making power can be related to overfueling - generally, a lean boost AFR like 12.5:1 will make lots of power, but not for long.

You should be making 600bhp at the crank, missing a hundred horsepower points to a combination of things, but mostly I'd say it's the mapping. Do you have an in-car wideband lambda?
 

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plkettle - that is simply not correct. Maybe on your specific car. Walbro 255ltr/hr pumps have issues at high supply pressure.

The HKS or Tomei 280ltr/hr pumps work fine at 1.7bar boost / 600PS. 75% duty cycle on 720cc SARD injectors, fuel pressure flat at 4.8bar.

Std lines, std rail, nismo fpr, tank mounted pump. All checked from datalogging.

And given that the AFR is quoted as low 11, the fuel pump would have zero impact on engine power.

If the elbow / intercooler / pipes / cams etc are below par your actually running at much higher pressure ratio at the turbo. More air heating, lower vol eff through exhaust side, lower ignition limit etc etc.
 

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Il be takn Exscooby T s advice on this one..!!il be running the hks 280l/ph intank,720cc + injectors my tomei fpr, std rail, and std lines..:thumbsup:a friend of mine does run two bosch pumps,swirl pot,hks rail,fpr uprated lines 1000cc injectors etc but he is running twin top mounted hks 2835s and 562bhp at the wheels which to be fare is a different set up to the set up il be running..(2860-5s and between 510 to 520 bhp at the wheels)i would much rather less power and alot more responce and also no stink of petrol in the car from 2 pumps!!!
 

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I can't believe your having so many problems with such a simple upgrade, and i wouldn't be going anywhere near a drag strip if it's set up so badly it's loosing 100bhp somewhere.
You need to take it somewhere that knows what they are doing, all the problems you've listed can be verified by various (basic) test methods :)
 
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