Rb26Dett With Mods Not Making Power :-/

[livewire]

Hi guys, just lookign for some input on my current situation.

My stagea autech had N1 Le mans turbos fitted (rated 640hp), adjustable cam gears, 700 injectors, upgrade fuel pump, greddy profec b boost controller and power fc fitted a few weeks back in Sydney and i was a little dissapointed with the result. It made 251kw at 17 p.s.i but was running on 20" rims on a 34 degree afternoon. On the way home afm's started playing up so have since purchased a set of nismo ones and had them fitted and car re-tuned today and still not happy as i was hoping for and told by nearly every tuner ive spoken to that 300-320kw should be what i'de expect to see.

Car made 265kw with nismo afm's at 17 p.s.i with factory rims back on which i think are 16' maybe?

The tuner couldnt seem to work out what is holding it back but said it was just simply a dud lol.

Tried unbolting the cat thinking it may be the issue but it is a catco highflow cat and unbolting it only made a 6kw difference so its not that.

He also said that with a 3 p.s.i increase to 20 p.s.i in boost it was gaining only 3hp so there is a restriction of some sort somewhere. I've read alot of comments on factory airbox and intercooler being fine for the 300kw target but these are the only 2 things i can think of that havent been changed.

List of current setup is:

Power fc

Nismo N1 GT LeMans group A turbos

xforce dump pipes

2.5 - 3" front pipe

Catco highflow cat

3" mandrel bent exhaust and 3 inch highflow straight through muffler

JJR adjustable cam gears

Walbro intank 255l fuel pump

Nismo afm's

factory intercooler and piping

factory airbox and snorkel with K&N panel filter

Greddy profec B spec 2 boost controller

Any suggestions or comments on whether the power figures seem fairly under performing for these mods or if someone has run into the same situation and what was restricting it?

From what i have researched i should definatly be seeing around the 300+ kw mark and its frustrating me having spent the money buying the parts i thought would get me there to fall a good 40+ kw short.

Edited December 1, 2011 by livewire

[Duncan]

Agreed, about 300 is right for those turbs at 20psi. They are pretty crap unfortunately, you would have 350+ with the same setup running -5 of similar instead (and with less lag).

Dropping the zorst was a good call, and the other stuff like intake, cooler, airbox etc would be fine for that power level.

Are you certain the timing is correct, and what cams does it have? Sure there is no boost leak and that the fuel pressure is OK?

[OoskylineoO]

lol could be a 101 things why its not making power...should do some tests to narrow it down.

[tridentt150v]

I'd do a double take on the walbro...........get a tomei/bosch/nismo and re try. Also see the FAQ section on using a dedicated earth lead for your pump.

Also try taking your K+N panel out and running without it just to check.

[OoskylineoO]

mayb evn try a different tuner LOL

[DVS JEZ]

Pic of the dyno sheet please.

What are the cam gears set too?

Are the standard intake pipes sucking closed?

Comp tested the motor?

[Global_Warmer]

Pic of the dyno sheet please.

What are the cam gears set too?

Are the standard intake pipes sucking closed?

Comp tested the motor?

It's running 8degrees on the inlet and 4degrees on the exhaust.

Engine sounds bloody healthy IMO.

[DVS JEZ]

Thats crazy. Try backing the intake off heaps. Maybe 4 and the exh to 2.

Did they play with cam timing?

[Global_Warmer]

Thats crazy. Try backing the intake off heaps. Maybe 4 and the exh to 2.

Did they play with cam timing?

Not today. I believe the previous mechanic/tuner did last week when the adjustable cam gears were installed.

[DVS JEZ]

Find out from them if u get a chance tomorrow. May be the issue.

Did u tune it with stock gears at all?

[GTR_JOEY]

Very interested to see how this goes......

[DVS JEZ]

My personal car has the exact same setup and makes 296kw safely.

[Brezza]

i'd be looking at comp testing the motor.

or possibly setting the cams back to zero and seeing if it makes any difference?

i had a very similar setup to you appart from using -5's and was making over 300kw @ 17psi

the std intercooler is fine for 350kw and i'm still using std airbox at 365rwkw

youre exhaust sounds to be adequate enough for that power, not too sure about the xforce dumps? i have never used them so can't coment on them?

i would do the following:

set cams back to zero and test

check all piping for leaks

comp test the motor.

hopefully that'll give you a reason why such a low figure

[R31Nismoid]

When the CAT was dropped, did that mean the entire exhaust was dropped when the run was done?

Ie - Front pipe ONLY connected?

Agree with the others though, check the cam gears belt etc. Most instances of stock-ish cars not making power is when cam gears are installed and they are out, or incorrectly set etc.

[livewire]

Hmm thanks for the input guys. Can only hope its not to do with compression :-/

The guys yesterday checked the cam gears and and said the 8 degree inlet and 4 degree exhaust isn't out of the ordinary so kinda eliminated that. Will see how a compression test turns out I guess. Otherwise its got me beat

[livewire]

And yeah nismoid, they just dropped the exhaust from the front pipe which eliminated the exhaust being the issue

[R31Nismoid]

Out of the ordinary and not being set right are often two different things.

Not saying they have got it wrong, but too often people have "double checked", only to take it for a second opinion and bam - in 30mins it's fixed with it being checked again.

[livewire]

Hmm true. Getting compression test done asap anyway to get piece of mind or save going all the way back to Sydney for nothing. If compression test comes back ok then I guess its a matter of dropping it off to a workshop with a lot of experience with them to eliminate possibilities. More f!$king money lol. And no doubt I'm gonna be up for a third tune cost too

[SargeRX8]

My car had similar issues, made little to no more power no matter what boost we threw at it. Ive more than likely got an intake restriction with my shitty intake pipe.

[R31Nismoid]

GTR & GTS-t = not same.

GTR intake piping has support internally.