GTR running like sheeet.

[MidnightGTR]

For starters ill start with the main mods. RS580 turbos (similar n1 spec), PFC, sard 700cc's, bosch 044 intank, 100mm cooler, turbos back exhaust, PFC, AVCR, RB20 80mm afm's.

I recently had my car dyno tuned and it made about 230kw at all 4 at 17psi (weak I know) and they basically just told me it wasnt making power because of the boost controller and how they are useless. They said gtrs with just some pods, exhaust and pfc running 1bar generally make that or more with standard everything else.

I just had it back on the dyno the other week and now im told there is a restriction somewhere, like a boost leak maybe, said it could be a ton of things, including bov's leaking, cat melted down and blocking airflow etc. The engine is fine and has perfect compression and no noises etc

I know the car is definatly down on power because the car doesnt feel much quicker then what it was stock, and for the money ive spent it should be heaps quicker. Week by week it actually feels like its losing power

Just lately its been playing up doing things like;

- hunts on idle occasionally

- wont boost over 0.3bar sometimes, sometimes it will

- and just recently it started surging very slightly at low speeds off boost just accelerating normally, but today I went to take off and it surged badly, tried to accelerate a little it just wasnt going.

Next im getting rid of the bovs for a single greddy type s incase they are leaking, and "high flowing" the cat abit more. If those 2 things dont fix it then im going to have to get my mechanic to start pulling it to bits and double checking everything till we find the problem.

My question is has anyone had any experiences with these symptons and what are the likely things (things to check for first) if I have to start pulling it apart.

Thanks for any advice

[Boosting]

WEll first no i have not but if u got it built take it back to the guy who did it. he should fix it cause he didnt do it right my 2 cents.

If i payed for all that i would want it working hey

[MidnightGTR]

Its a long story but from the start it has been down on power but theres always excuses as to why its not going like it should. Its only just recently started running worse and doing this crazy shit so its hard to say.

[voona]

Sorry to Hi-Jack your thread but THIS SOUNDS LIKE MY CAR. If you work out the problem let me know. Mines basically stock and it wouldnt crack a 15 sec 1/4 . It has the same problem as yours. Feels flat, no mid range power but doesnt make any noises or break down through the rev range. Go figure ..

Mine also hunts sometimes and does various wierd things as your describing. Make sure you PM me if you find the cause and ill do likewise ..

[JAGR33]

MidnightGTR - as a word of advice don't change the BOV's, they never leak and many guys are running big power (800hp+) with no probs....

It might be a long shot but check ur intake manifold gasket for leaks.....

[pentae]

well have you checked the cat? get underneath the car and give it a smack with your fist.. if you can hear the bits of sh*t rattling around inside it when you tap it, get a hi-flo cat.

[600hp]

Just take the cat off, take it round the block with nothing on.

You may want to fit a boost controller, and see if that helps.even if is doesn't it will help you later when you want to increase power.

make sure no one left a rag in the intercooler, as i have heard of it before and having simillar effects.

[Gts-t]

Along with what everyone else is saying i would check out the fuel system. A stuffed fuel regulator could explain your problem.

[cameron]

  MidnightGTR said:

PFC, sard 700cc's - hunts on idle occasionally

Tuning, 95% of the time its hard to get rid of hunting on idle with bigger injector's, but its down to tuning. - generally happens on hotter day's.

  MidnightGTR said:

- and just recently it started surging very slightly at low speeds off boost just accelerating normally, but today I went to take off and it surged badly, tried to accelerate a little it just wasnt going.

Again this sounds like the tuning, simply take off at higher rpm.

I would start with the basic's first, cleaning the AFM's, checking plugs, looking for leak's or blockage's etc.

Maby even post you'r inj map off the FC if its possible... this would help.

[always_me]

my mate just got his power fc installed andcat back exhaust, adjustable cam gears and is running 186kw@all 4, is this about right? also 15psi.

[cameron]

Nice hijack!

He needs to get a set of 3" dump pipes.

[ferni]

Sounds to me like you need to take it to a new tuner - they should be telling you whats wrong and fixing it, not saying 'ummm theres something not right, we dont know what it is tho'

As for power, with your mods (nfi about turbos, but assuming they are like N1's) you should be making close to 300rwkw... i've got stock turbos, exaust, 1bar boost and make 270rwkw...

[Squizz]

  always_me said:

my mate just got his power fc installed andcat back exhaust, adjustable cam gears and is running 186kw@all 4, is this about right? also 15psi.

No that's shithouse.

[morlock]

Could be faulty O2 sensor or AFM's are buggered. This should be pretty apparent on the DYNO....sounds like your tuners know Jack S**T.

Check all your IC hoses for leaks. How many K's has the car done?? wouldn't have thought it was the cat if it has done under 100,000.

[morlock]

What are your air/fuel readings like?? is it richening up occasionally or is it pretty flat.

[7heavn]

  voona said:

Sorry to Hi-Jack your thread but THIS SOUNDS LIKE MY CAR. If you work out the problem let me know. Mines basically stock and it wouldnt crack a 15 sec 1/4 . It has the same problem as yours. Feels flat, no mid range power but doesnt make any noises or break down through the rev range. Go figure ..

Mine also hunts sometimes and does various wierd things as your describing. Make sure you PM me if you find the cause and ill do likewise ..

Voona have your cam timing checked it is in alot of cases the cause of a low performing GTR that doesn't do anything wrong just has no power and response .

[marchGTR]

  always_me said:

my mate just got his power fc installed andcat back exhaust, adjustable cam gears and is running 186kw@all 4, is this about right? also 15psi.

it depends on the dyno! my gtr dead stock made only 147AWKW (12psi stock) and with the restrictor removed made 169 AWKW (14.5PSI). to me that seemed a bit low although the improvement was substantial and it felt quick on the road. incidently it also ran 12.8 at 106 at this power so it definately was running well! so I guess it depends a lot on the dyno and a before/after comparison is often more accurate.

[ricknismo]

I'm thinkin boost leak...shove a plastic cup in the hose each air filter is in and rip off one of the boost lines. Us e a compressor to presuurize the whole lot, from turbs to plenum..spray some soapy water around and look and listen for air leaking.