Jump to content
SAU Community

Recommended Posts

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

Link to comment
https://www.sau.com.au/forums/topic/71444-gtr-running-like-sheeet/
Share on other sites

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 ..

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.

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.

- 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.

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...

Sorry to Hi-Jack your thread but THIS SOUNDS LIKE MY CAR. If you work out the problem let me know. :rofl: 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 .

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.

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.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • To expand on this to help understanding... The bigger/longer the block is, the more it's going to work to sit on your far away high areas, and not touch the low stuff in the middle. When you throw the guide coat, and give it a quick go with a big block, guide coat will disappear in the high spots. If those high spots are in the correct position where the panel should be, stop sanding, and fill the low spots. However, using a small block, you "fall off" one of the high spots, and now your sanding the "side of the hill". Your little block would have been great for the stone chips, where you only use a very small amount of filler, so you're sanding and area let's say the size of a 5/10cent piece, with something that is 75*150. For the big panel, go bigger!   And now I'll go back to my "body work sucks, it takes too much patience, and I don't have it" PS, I thought your picture with coloured circles was an ultra sound... That's after my brain thought you were trying to make a dick and balls drawing...
    • Oh I probably didn't speak enough about the small sanding block for blocking large areas.  In the video about 3 minutes in, he talks about creating valleys in the panel. This is the issue with using a small sanding block for a large area, it's way too easy to create the valleys he is talking about. With a large block its much easier to create a nice flat surface.  Hard to explain but in practice you'll notice the difference straight away using the large block. 
    • Yep I guessed as much. You'll find life much easier with a large block something like this -  https://wholesalepaint.com.au/products/dura-block-long-hook-loop-sanding-block-100-eva-rubber-af4437 This is a good demo video of something like this in use -    You have turned your small rock chip holes into large low spots. You'll need to fill and block these low spots.  It's always a little hard not seeing it in person, but yes I would go ahead and lay filler over the whole area. Have a good look at the video I linked, it's a very good example of all the things you're doing. They went to bare metal, they are using guide coat, they are doing a skim coat with the filler and blocking it back. If what you're doing doesn't look like what they are doing, that's a big hint for you  
    • The odometer does go up when driving.  Does this tell it is an issue with the speedometer itself?    Where can I look for replacement cluster? Or speedo? I can likely do the repair.. Will ER34 cluster work on HR34? Or do I need a HR34 20GT S2 specifically lol   
    • Mine's a bit bigger at 70x150mm roughly. The spots are flat, just can feel the edges if I dig my nail into it. I did fix some other other ones by both using my finger to sand that small spot (I'm a bit wary of doing this and creating hot spots and a bigger mess) and I also did sand over it flat and others, but this also worried me a bit because if I create an overall low spot on the panel on paint that is good.  Correct me if I'm wrong but as long as it's flat even if I can feel the edges, I can put filler because it will all be level once I sand it? I can see myself going in a circle after sanding guidecoat with 320 grit if for example the panel is flat with my hand but because I sanded the guidecoat I could have created a low spot again somewhere. Unless where I'm going wrong is what I mentioned previously where I didn't go low enough on the grits. It's 1 step forward and 2 step backwards here haha. I'll probably need to experiment with it more. Last time I go back to bare metal lol.
  • Create New...