Built Gtr Not Making Power

[Shazz]

Hi I'm in need of some advice, so hears the story........

I have a r33 GTR with HKS gt-rs turbos, HKS manifolds, dumps etc. and all supporting mods. On a standard motor internally it made 460hp at 18psi.

Now have a built motor with 264 deg cams, valve springs etc etc. got on the dyno the other day. The car wouldn't make boost. Re routed some vaccum lines and seemed to fix the problem. Then te car was making 22psi and started making less and less boost. Te end result was 350hp at 15psi which is shithouse. Now here's the kicker. The boost gauge and apexi avcr both tea 1.30 kg/cm2 however it was only making 15psi on the dyno. Turning the boost up to 1.70kh/cm2 on the avcr and both the avcr and boost gauge read that but no difference in power.

I have replaced the exhaust going larger thinking it could have been an issue, made it rev freerer but did not fix the issue.

Could this be an issue with vaccum lines run incorrectly? Any other suggestions as to whatnot could be?

[Shazz]

Car is running currently on waste gate with the boost controller turned off and it's reading 1.30 kg/cm2. I believe the adjustable actuators aren't set exactly the same cause in getting a bit of turbo shuffle, but surely that can't be the main issue

[SiR_RB]

Making less and less boost?

I had the same problem, ended up been a split in the intercooler hose that connects to the Twin Turbo pipe, but it was underneath and you couldn't see it

[Shazz]

Ill check over my cooler piping, however I installed a greddy intake kit only a month ago, so it should be all good. It's settled now on 15psi for the las two weeks

[GTR_JOEY]

Making less and less boost?

I had the same problem, ended up been a split in the intercooler hose that connects to the Twin Turbo pipe, but it was underneath and you couldn't see it

i agree if it was making less and less boost it sounds like you have a leak,

do the "twin turbo pipe mod" to try and eliminate that shuffle

[Shazz]

Not running a twin turbo pipe, running a greddy intake kit, the shuffle I believe must be a difference in actuator settings

[Jayden.K]

make sure your bov isnt creeping open, and just check the tightness of all pipe work. you only get a leak at a certain point so it sounds like a small but its there

[Shazz]

Ill go over the intercooler piping Friday ad let you all know. I have checked the bov's by swapping them with another set, but still same issue

[R31Nismoid]

just smoke test it? You'll soon find the leak

And GT-RS's just shuffle, same actuator pressure or not, most people never get rid of it.

[paulr33]

pressure should be fairly static once target boost is reached

if its not theres a pressure leak or restriction

[Shazz]

just smoke test it? You'll soon find the leak

And GT-RS's just shuffle, same actuator pressure or not, most people never get rid of it.

Can you elaborate on smoke testing it?

[STATUS]

check to BOV's are hooked up correctly i often see the vac/boost reference line swapped around with other lines in the vicinity and they bleed boost like nothing else... on a std gtr its around a 40rwkw loss.

[Shazz]

The vaccum line runs from the iav valve to the bov, is that correct?

[Frosty]

smoke test!!

[Shazz]

Can some explain a smoke test, never heard of it before

[R31Nismoid]

Fill intake with smoke, pressurise - see where it comes out

[Frosty]

further more and may sound stupid but are you sure you have hooked up the vacuum lines correctly to the boost controller/wastegates??

[scotty nm35]

Just compressed air works well, make up a bung for the intake of the turbo and pump 30psi into it. Blowing bong smoke up there just makes the escaping air easier to see but you will hear any leaks just fine.

[Shazz]

ill try to pressure test/smoke test it this weekend. As far as vbaccum lines are concerned it is certainly possible that i have my vaccum setup incoreect. ive been searching etc, but cant seem to find a difinitive answer on it all.

[Shazz]

i have double checked my vaccum lines etc and they all appear to be as they should. i noticed the other day when the car gets warm it idles at around 1300-1400 rpm, so that to me suggest vaccum leak. however ill check the intercooler piping and go from there