1G GSX help?

[matt98eclipse]

I just bought a 91 gsx with 107,000 origanal miles. the car runs great except at idle the rpm's bounces a little??? I also noticed it takes a lil while to build full boost! At full boost its only at 7 psi! On a COMPLETELY stock motor how maney pounds of boost should I be seeing??

 

[ALLBoostAWD]

Stock boost is 14psi. Your Dash boost gauge is not correct, ever. Buy an aftermarket one before doing anything to the car at all.

 

[matt98eclipse]

Ill have to go buy a boost gauge and see what it reads then and what mod's should i start out with doing to make it quicker?

sorry guys I am new to the whole 4g63 motors!

 

[Talesin]

Stock boost with the BCS in the loop and un-modified for a 1G is 12psi. Stock boost for 2G is between 14-15psi (14.7psi, 1 BAR). And yeah, the gauge cluster 'boost gauge' is just an ECU guesstimate of how much you're boosting, not an actual pressure read.

Read through the tech articles section (top left of the page, TECH/DIY link), they have power upgrade paths for making numbers on a dyno/at the strip. It really depends on what you're going to use the car for... focus on drag strip power to have fun getting shoved back in the seat, or go for a more nimble rework, redoing the suspension properly, getting better tires (and wide enough rims to handle the rubber), and lightening the car to let it handle TONS better. Personally, I'd say swapping the rear swaybar for a thicker ST unit, and replacing the rear rubber control arm components with the metal inserts would yield the most immediately noticeable handling upgrade, followed by a good set of shocks, and then a good set of springs.

 

[kenamond]

The bouncing idle sounds like idle surge. Search around, and you'll find out how to deal with it. But before you do that, do a boost leak test. Again, this is described thousands of times on this forum, so a bit of searching should properly educate you. After you boost leak test and fix the leaks, then move on to other issues.

 

[matt98eclipse]

Thanxs guys Im really lookin forward for some power to set me back to the seat type! I really think i have a boost leak, I made a custom boost leak tester for my old 98 rs-t with a t3/t4 but that one had a 3inch inlet! Ill be needing to do some more searchin on the forums on how to make one for the 14b turbo's??

 

[jeharrisonjr]

Dont forget to check your BISS screw and O ring, thats what ended up bing my fix which was cheap and easy.

 

[Talesin]

Check VFAQ.com for detailed instructions on how to make a boost leak tester. Essentially it's just a certain size PVC pipe end-cap, a short bit of radiator hose (4-5" should be more than enough) that the cap will fit snugly inside, a press-in tire inflation nipple, and a pair of worm gear clamps. Drill a hole in the PVC endcap, install nipple, slip the PVC pipe end inside the radiator pipe and clamp it down. May want to add some silicone sealant to that (applied to the outside of the PVC endcap, and the inset around the base of the tire nipple) to help everything seal up properly so it won't leak any air itself, and give you a false boost leak.

 

[PSITSI]

If your blow off valve isn't recirculated, that will certainly affect your idle.

 

[Talesin]

Mostly as the stock 'BOV' is actually a CBV, and is open at idle, pulling in unmetered and unfiltered air. An aftermarket actual BOV (closed under vacuum) will only get the problem where you run pig-rich after blowing off, due to the loss of metered air.

 

[matt98eclipse]

Thanks Talesin, I have done some research and found exactly what your talking about! Hopefully I can get to it today! as far as the bov, it is recirculated back into the intake. If I was to do the open atmosphere with the stock BOV, would it hurt anything?

 

[Talesin]

Yes. Read the newbie FAQ, and my post right above yours.

You'll run painfully lean at idle as unmetered and unfiltered air is sucked in, and pig-rich after you blow off due to the loss of metered air. To properly atmo-vent, you either need a MAF-T setup, a VPC setup, or one of the speed-density options in DSMLink or AEM. Going to an aftermarket 'true' BOV will only get rid of the lean at idle, with the stock Karmann Vortex MAS. You'll still run pig-rich (read: farting black smoke and bogging like crazy) after you let off the throttle while under boost.

Typical newbie mistake is to atmo-vent their CBV/BOV without the proper metering alterations, to try and make their car sound Riced & Curious.
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