lots o lag

[95gsxtreme]

I have a 1995 GSX w/ 64k miles, it seems begin too spool ok around 2800 rpm with factory intake and exhaust, but slow to reach max boost like 6800 rpm...when I let off the throttle to shift, it seems to lose all spool and I have to wait for like seems like a lifetime for it to spool back up. I am used to driving an STI, but I've driven many turbo vehicles and this seems to be the slowest as far as spool. And that factory flywheel must wheigh a ton, the RPMs tach up so slow...is it just me or is this stuff normal for these cars?

 

[Precision]

That's not normal at all. Sounds like you have a turbo going out of a huge boost leak. Have you checked for shaft play or anything that would cause that slow of spool.

 

[MyBeatGSX]

How many millions of pre turbo exhaust leaks do you have? That's where I would start. Check for a cracked manifold and make sure the manifold and turbo gaskets are still in place and all the bolts are tight.

Also make sure your wastegate isn't stuck open.


And yes the stock flywheel does weigh a ton

 

[95gsxtreme]

thx, I'll have to leak check the intake piping...I don't have any exhaust leaks that I can tell, I haven't smelled anything even when I stand over the bay with the car running...is there a better way to tell? No I have not checked for shaft play, how is this done?

 

[fourreGsixty3]

Take the stock rubber intake pipe, and try to wiggle the turbine side to side( a little is ok, but make sure when you wiggle it that the fins dont hit the turbine housing, also pull on the turbine piece that sticks out to check for in and out shaft play, there dshould be non of the in and out shaft play. with a lighter fly the rpms will go up quicker due to less rotational mass needing to be spun. have you done a exhaust leajk test? If not then do it to be 100%.

Dustin

 

[MrBoxx]

Take off the intake hose. Stick your fingers into the compressor housing of the turbo. Grasp the nut in the center of the compressor wheel. Try to wiggle it up and down, side to side, and in and out. If there's ANY in and out play at all, the turbo bearings/seals are failing. A very small, barely-noticeable amount of side to side/up and down shaft play is okay; that play is taken up by the oil bearing when the car is running. If it's more than noticeable, as in a few millimeters, the bearings/seals are likely to be failing. Check also for signs of the compressor fins hitting the compressor housing inlet or other damage to the compressor fins. In addition, the compressor wheel should spin freely.

First and foremost: boost leak test.

Slow spool causes slow acceleration; the weight of the factory flywheel has nothing to do with it.

 

[MyBeatGSX]

I don't have any exhaust leaks that I can tell, I haven't smelled anything even when I stand over the bay with the car running...is there a better way to tell?

You'll never smell it, no matter how bad it is.

Start the car cold and feel around the underside of the manifold, between the turbo and manifold, and between the manifold and head. Rev the engine if need be. You'll be able to hear it if its leaking anywhere. Pre turbo exhaust leaks are very loud.


I'm going to go against a boost leak on this one. It would need to be absolutely MASSIVE to delay full boost until 6800rpm. You'd be fuel cutting all day long with a leak that big, the car would hardly run. It has to be an exhaust leak or dead turbo.

 

[95gsxtreme]

actually a heavier flywheel does take away from acceleration, not like I'm experiencing though. In a much heavier flywheel there is more rotational mass for the engine to turn, that creates more drag on the motor, thus why RPMs tach up much faster with a lighter flywheel. In this case I asked because the motor tachs up so slowly, not because I think it is the issue for my lag in power. thx for the help on the turbo question.

 

[MrBoxx]

Might as well do a boost leak test while the intake hose is off anyway, though, right? Especially if one hasn't been done on the car before.

I'm also betting on an exhaust leak of some sort or something impeding free spinning of the turbo.