OKay heres the deal, the vtec always works on my 95 gsr. All i have is innovative motor mounts, and a Intake system other then that its stock. My vtec always kicks in at 5900.
So i went and installed a testpipe with the 02 sensor pluged in and the whole catback system, took it for a drive and no vtec. so i took off just the exhaust axle back and put the stock muffler on and vtec worked. I am really confused, all my grounds are good, oil is leveled, selonied is tested on another car and worked fine, and tried diffrent ECU still didnt kick in with the aftermarket catback. What could be the problem here? seems like its from the exhaust but that does not make any sense here?
any thoughts?

 

It doesn't make sense. Is the engine light on?

 

Are you sure your not hitting vtec? Could the exhaust have smoothed out the "dip" so you dont feel it hit as hard and it just FEELS like its not kicking in?
Weird...
Sounds like a defective exhaust LOL!

 

LOL! This is simple. The exhaust - obviously being more free flowing - takes away from the "engagement" sound. Better performance though

 

Yea ***** really weird, but no there is NO CELS.

And yes it might be the flowing thats hiding the vtec kick, but still..... maybe because its not top brand like skunk2 or apexi, thermal etc....? but no again does not make sense.

 

doesn't make sense at all....sounds a bit weird....I have a aftermarket header/exhaust/muffler and i can't tell when the vtec comes in at all in first gear but when in second or third it's a different story...ever tried those gears?

 

That makes no sence you probally dont hear that transition anymore with a catback but yeah lol Never heard that one before.

 

It makes perfect sense. But oh well..

 

Stock GSR VTEC is NOT 5900rpm. Maybe this is the problem.

VTEC Switchover : 4400 rpm
IAB : 5750 rpm

What you hear is the IAB activating. Your new exhaust has smoothed out the engagement. Less noise more power.

 

This is pretty much the answer to your question, so there is nothing wrong with your setup, its just the exhaust flows more and got rid of the restriction that caused the louder vtec before.

 

Truth

 

Ok - this thread is rice. Lock please.

 

you dont have enough backpressure for vtak to kick. also you may try to replace your muffler bearings!!!!

 

Put another quarter in it!
Press the VTECH button.