Gtr Engine Just Rebuilt, Feels Like Power Lost

[BlackR32]

Hey all,

hoping for some input: I just rebuilt my engine have had the oil pump die and drag my crank to hell with it... so new crank, bearings rings pump and so on...

No I am running the engine in at the moment and on the home stretch, but the car feels like it lacks power compared to what it used to... I drove my house mates supra the other day which has nothing on my GTR and I swear its running faster than mine (

It's still on "running in" fluid, I have a Greddy boost gage and a HKS EVC which reads the boost also... and of course the stock gauge which means nothing to anyone... the Greddy gauge isn't reading properly, its just bouncing around and not actually doing anything even close to measuring vac/boost thats just because I havent connected the electrics back up for that properly I assume.

The HKS EVC is messuring me at 6 pounds which is what I always ran but the car just feels a little lack luster.

By rights I would have though... considering the head was shimmed before putting it back on and the rings have been replaced, my compresion should be a little even if not measurably higher.

So the engine is back together to every spec and torque...

Any ideas?

[bnr#@]

Isnt 6psi a bit low for a gtr? thought it was closer to 10psi stock

[Inline 6]

pretty sure stock is 7pound is standard. im sure i read it somewhere and thats what the standard gauge reads up to.

maybe your workshop set it on 6pound to make sure you take it easy on the car while it runs in.

[RB26TTVL]

I would have thought 9psi for a stock GTR?

[seeyagtr]

The stock boost is 10pis with the orifice removed it will boost to 12psi

Sounds like a hose problem....

[BlackR32]

Hey all, thanks for the help so far, but it only ever sat on 6 psi, and was plenty fast, sometimes when I was feeling adventurous I would lift it up past 10 psi but not really very often.

Any other thoughts?

I will look into that though thanks )

[arbess]

stock boost is not 10psi.

for those who think it is, go and redo your maths. the guage is mmHG not psi.

Stock boost sits around 7psi.

your problem could lie in electrical. maybe an AFM, its hard with cars like these, problems lie everywhere. good luck

[datsqik]

Ignition timing and cam timing the same as when it was pulled apart?

[Duncan]

or possbily even timing belt one tooth out. but more likely base timing is wrong when you put the CAS back on

[GTR 400]

Yeah i agree stock boost is 7 Psi i had mine on the dyno and with stock exhaust everything stock it didnt produce more than 7Psi we took the restrictor out and even then would raise more the stock exhaust was out of flow efficiency car wanted to boost but couldnt get the gas out .

Even the standard boost gauge goes to 7psi also, i have witnessed everything that i have talked about have a good friend with a dyno and we played with the R32 that night to see how it ran stock, let me tell you also they run very pig rich in fuel side of things good to know as the ecu will accomodate a boost increase with A/F ratios that Nissan gave the Gtr.

Cheers,

Dave.

[infamous_t]

GTR Stock boost gauge is in mmHg, 7(x100)mmHg = 13.5psi.

If your HKS EVC is reading even remotely accurate that still means less that half boost of what your used to.

[Duncan]

standard boost on a GTR is 0.8bar (11.5psi) per the workshop manual.

[BlackR32]

ok then, now I have not walked out to teh car to check, but suppose the EVC is reading in mmhg as well... that would mean I am still on the right boost and getting no power at all.

Can the cam angle sensor being slightly off cause this problem? I marked everything for replacing and its all in the same spot but still shit happens...

I really appreciate your help so far all.

[BlackR32]

checked hoses, still nothing...

any other ideas?

[infamous_t]

but suppose the EVC is reading in mmhg as well...

This is the new HKS EVC? I know that one is kPA(bar) or PSI selectable.

The HKS EVC is messuring me at 6 pounds which is what I always ran but the car just feels a little lack luster.

Therefore your running 8.7psi(0.6bar) or 6psi. well under stock.

[Katatonic]

I'm under the assumption that, this is just a simple mistake of reading the PSI / thinking it was set at something different?

It also sounds like you've done the work yourself? Since you say you haven't hooked up the gauges properly etc.

[GeeTR]

Strange indeed.

Boost - #1, id check the EBC for what unit of measurement its using. Hook up your lecky gauge properally, or use a known good mech unit from a mate, run some dodgey hose out the bonnet, through the window; good to go in 30seconds.

Power - was it built for same compression? same headgasket etc? Are you noticing lack of go when under load, or does it seem to free rev tightly? Talk to your engine builder about bearing clearances. You prolly at this point check ignition, do a quick comp test (Just for shits n giggles, results could be hard to compare depending on KM's of run in)

As for boost, the manual might say 11.5psi, but iv def seen 8 on more then one car. When mine hit the shores of this dry country, it'd run 10.something psi, with pods and a cat back so who knows.

Hand the thing back to the tuner when run in, crank a few bar into it, then complain about the 20kw loss...

.. oh and wax that 2JZ

EDIT: Pretty sure most ppl see 1bar with restrictor gone SeeyaGTR

EDIT2:

The HKS EVC is messuring me at 6 pounds which is what I always ran but the car just feels a little lack luster.

Could you have ran 6 pounds, which is lower then the factory gate pressure? Me thinks you'd have to have your units of measurement mixed up.

Edited September 22, 2007 by GeeTR

[BlackR32]

yes it reads in mmg or what ever, just had a look...

now heres teh thing, it revs up perfectly, you cannot fault the car for how smooth it is running, but I just got smashed by a v6 magna...

so the pressure is reading at 0.6 mmg which it always did, and the car just has no go.

you can feel the boost but it doesnt kick you in the arse like it did before build.

[Duncan]

have you checked for sure the timing is OK, if it is retarded it can make the car super sluggish.

[BlackR32]

now do you mean up at the cam angle sensor?

Becuase I always figured that if I was a tooth off it wouldnt run smoothly.