car:95 240sxmotor and modss14 blacktop sr20det w/ 5spd
fmic, s13 cams, cold air intake, buddyclub specII, off brand turbo elbow, and MBC set at 7psi
stock everything else
i put on a tomei expreme manifold kit last night, it was running fine before i did it--minus a leak at the flange due to missing nuts and 1/2 of a gasket
after putting on the manifold my idle sits at around 1500. it drops then shoots back up. ive already tried to adjust the idle screw...it does nothing...all it will do is raise the idle. i cant get it to drop.
i can also hear the turbo surging through the intake..not the hot pipe.
is THIS normal.
is my bov needing to be adjusted due to more air spinning the turbo from the upgraded exhause manifold?
weird stuff after new manifold installed
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rancidjack
- Posts: 14
- Joined: Tue Mar 25, 2008 5:48 am
- Car: '95 240sx with sr20 swap
Re: weird stuff after new manifold installed (rancidjack)
What? No, a new exhaust manifold won't make you have to adjust your blow off valve. Nor will it effect how the car idles. There isn't even any more "air spinning the turbo".
You have to understand that an aftermarket exhaust manifold really doesn't do anything but increase the limit of the amount that exhaust gasses can leave the motor efficiently. Just because it CAN flow more does not mean there automatically ARE more exhaust gasses flowing through it than there were previously. Their purpose is for when your motor is modified to the point that the stock exhaust manifold actually becomes a significant restriction (which is probably over 350hp), or for when you have money to burn and just want some shiny pipes under your hood.
Hopefully that allows you to understand a little bit to realize that If you replace an exhaust manifold with another of higher capacity, and suddenly the car doesn't run right and your BOV doesn't open, then maybe messing with the idle valve shouldn't be the first thing you do.
Go back over your work and make sure you didn't accidentally leave a vacuum line or something else unhooked or loose.
and I'm confused about what you're saying about hearing the turbo surging through the intake but not the hot pipe. By "hot pipe" do you mean blow off valve? because you should never be hearing ANYTHING coming from the hot pipe. Not unless it's disconnected, in which case the car would hardly run and there would be no possible way for the turbo to surge at all.
Modified by Neil at 7:36 PM 10/5/2008
You have to understand that an aftermarket exhaust manifold really doesn't do anything but increase the limit of the amount that exhaust gasses can leave the motor efficiently. Just because it CAN flow more does not mean there automatically ARE more exhaust gasses flowing through it than there were previously. Their purpose is for when your motor is modified to the point that the stock exhaust manifold actually becomes a significant restriction (which is probably over 350hp), or for when you have money to burn and just want some shiny pipes under your hood.
Hopefully that allows you to understand a little bit to realize that If you replace an exhaust manifold with another of higher capacity, and suddenly the car doesn't run right and your BOV doesn't open, then maybe messing with the idle valve shouldn't be the first thing you do.
Go back over your work and make sure you didn't accidentally leave a vacuum line or something else unhooked or loose.
and I'm confused about what you're saying about hearing the turbo surging through the intake but not the hot pipe. By "hot pipe" do you mean blow off valve? because you should never be hearing ANYTHING coming from the hot pipe. Not unless it's disconnected, in which case the car would hardly run and there would be no possible way for the turbo to surge at all.
Modified by Neil at 7:36 PM 10/5/2008