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greddy slow to spool

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Old May 16, 2007 | 05:44 AM
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Default greddy slow to spool

I bought the car with a greddy tt kit and a blown engine. Replaced the engine and everything runs great now. It seems to be really slow to spool though and doesn't have the kick in the pants that my 300zx does. I'm only trying to run around 6psi right now till i make sure everything is good but I have to hammer the throttle and it will eventually hit around 5.6 psi. I use a smoke machine yesterday to check for leaks and found nothing. Any other ideas?
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Old May 16, 2007 | 05:47 AM
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Some pics would help.
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Old May 16, 2007 | 05:51 AM
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pics of what? everything is installed correctly. I'm just running the stupid emanage blue with e-01 right now but will be going to utec soon. My friend's g35 with aps tt and utec boost instantly and will hit 10psi before mine even gets to 2psi. He has a built motor but that shouldn't matter.
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Old May 16, 2007 | 06:07 AM
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What wastegate springs are you running?
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Old May 16, 2007 | 06:34 AM
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The price you pay for old school Mitsu turbos.
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Old May 16, 2007 | 06:37 AM
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at 6 psi you wont feel the kick like the 300ZX, the power feels more linear, you have to get to 8-9 psi to feel the kick, if the motor is a built motor wil lower compression then it will be worse.
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Old May 16, 2007 | 06:43 AM
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When are you hitting full boost?

Originally Posted by Devil Z
The price you pay for old school Mitsu turbos
Tell me that after I blow by you
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Old May 16, 2007 | 06:53 AM
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You should hit 5.5psi in 5th gear, by about 3200-3500rpm. If its spooling slower than that, you might an issue. Could be a leak, or worse...a failing turbo.
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Old May 16, 2007 | 07:03 AM
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If he were on spring pressure alone when would he hit full boost? I know when I run on spring pressure it takes a significant longer time to hit full boost, but I'm not sure if it is that severe.
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Old May 16, 2007 | 07:04 AM
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Originally Posted by KPierson
If he were on spring pressure alone when would he hit full boost? I know when I run on spring pressure it takes a significant longer time to hit full boost, but I'm not sure if it is that severe.
Yeah, I am assuming he is on spring pressure...so roughly 3500rpm.
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Old May 16, 2007 | 07:28 AM
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well i'm running stock springs, I have the boost controller set so essentialy it will run right around stock springs. I have tried adjusting the gain but didn't seem to help much. Here's what I don't understand. I am on stock block for now. I will build the block this winter, don't really care if I blow this one but would like to not. Shouldn't 9 psi and 5 psi feel the same up to 5 psi? Kpierson's car kicks in so fast. If I'm in 3rd or 4th gear I have to nail the throttle and it'll hit like 5lbs by around 4000 rpm or so. This just seems so slow to me. It basically seems like my wastegates aren't even having to open. To me it seems like it should get up to 5.5 psi or whatever quick then the wastegates should let out the air.
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Old May 16, 2007 | 07:34 AM
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You should go to a local dyno shop. Somewhere that will allow you to get under the hood while the engine is under load to check for leaks.

The turbos should have internal wastegates and if they are not attached and set properly you may get a very late spool. This happened to me on my Integra with a Greddy kit. The brackets for the wastegate actuator arm was loose and it was causing very late spool up. After I tightened everything back down and set the actuator arm I was getting positive pressure at 2.5k instead of 5k, huge difference.

Last edited by Nihilation; May 16, 2007 at 07:39 AM.
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Old May 16, 2007 | 07:46 AM
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Originally Posted by Devil Z
The price you pay for old school Mitsu turbos.
From all the dynos posted the APS TT doesn't spool any faster than the Greddy turbos. At least the old Mitsu turbos don't have a problem building boost and holding it like the APS turbos.

Last edited by Gman2004; May 16, 2007 at 07:49 AM.
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Old May 16, 2007 | 07:48 AM
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Originally Posted by Nihilation
You should go to a local dyno shop. Somewhere that will allow you to get under the hood while the engine is under load to check for leaks.

The turbos should have internal wastegates and if they are not attached and set properly you may get a very late spool. This happened to me on my Integra with a Greddy kit. The brackets for the wastegate actuator arm was loose and it was causing very late spool up. After I tightened everything back down and set the actuator arm I was getting positive pressure at 2.5k instead of 5k, huge difference.
The Greddy TT kit for the V35 does not have internal wastegates.
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Old May 16, 2007 | 07:51 AM
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Originally Posted by merlin3
well i'm running stock springs, I have the boost controller set so essentialy it will run right around stock springs. I have tried adjusting the gain but didn't seem to help much. Here's what I don't understand. I am on stock block for now. I will build the block this winter, don't really care if I blow this one but would like to not. Shouldn't 9 psi and 5 psi feel the same up to 5 psi? Kpierson's car kicks in so fast. If I'm in 3rd or 4th gear I have to nail the throttle and it'll hit like 5lbs by around 4000 rpm or so. This just seems so slow to me. It basically seems like my wastegates aren't even having to open. To me it seems like it should get up to 5.5 psi or whatever quick then the wastegates should let out the air.
What kind of exhaust do you have? Do you have TP's, cats, or high flow cats. You may have a lot of back pressure which is causing you to spool slower.
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Old May 16, 2007 | 07:53 AM
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when i was at 4.9 PSI i got a kick in the pants... when i was at 9 PSI i still felt a kick in the pants.. i am guessing maybe failing turbo's... any smoke?
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Old May 16, 2007 | 08:07 AM
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He has no smoke, test pipes, and true dual exhaust.
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Old May 16, 2007 | 09:08 AM
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Maybe the collars on the wastgates were not installed. If they arent, you turbos will spool really slowly.
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Old May 16, 2007 | 10:43 AM
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the collars that go inside the wastegates that seal them? I put those in there. If the wastegates were leaking wouldn't that show up when I hooked the smoke machine up to the intake on the turbos?
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Old May 16, 2007 | 10:59 AM
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Originally Posted by merlin3
the collars that go inside the wastegates that seal them? I put those in there. If the wastegates were leaking wouldn't that show up when I hooked the smoke machine up to the intake on the turbos?
Yup...so that sounds like thats not the issue.

Tuning can have alot to do, with how quickly the turbochargers spool up. Maybe you are just used to KPierson's higher boost setup.

Take it to a dyno, and have them plot your boost in 5th gear...this will tell you if you have an issue.


Not always, but usually, a boost leak will make some kind of sound..whistle..air rushing..etc..etc.
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