Ok guys, I know (from owning 3 GS-R's) that when you have an exhaust leak, it can really cut down on power, but...

This latest leak produced two interesting symptoms. The first is now it is very obvious when the VTEC kicks in and when the secondary air intakes kick in. Normally I know when the air intakes kick in (around 5700rpm), cause that's pretty obvious for anyone who has a ram air intake.

But normally the VTEC crossover point (around 5200rpm) is very subtle. But now, with this leak, I can feel a big surge in power (although still way down on power) when it kicks in. How come?

But the new thing is that know I'm getting a lot of knocking/pinging. It seems to happen with only small throttle "changes". Meaning, I can be going pretty much any speed, and then if I increase throttle only about 10% (maybe a half inch), I'll start to get pinging. If I increase it more, the pinging is gone. Any idea's?

David

 

if you have knocking/pinging, exhaust leaks should be the least of your problems. Sounds like your power is being reduced due to something internally (bad rings, bent valves, etc.).

FYI, vtec x over on the gsr is actually around 4400 rpm. The iabs (secondary butterflies) opens around 5750 rpm (the noise you're hearing is the butterflies opening).

 

Hmm...I thought I had heard that the cam change occurs at 4400 also, but mine is very obviously changing over at about 5200rpm. The Apexi VTEC controller must be set wrong. Thanks for setting that straight.

Anyway, turns out the leak is in the headers. Right where the 4 becomes 1. So I have to get some headers....anyone selling any used one's?

The pinging is very subtle and occurs in sort of strange circumstances. I'm thinking the O2 sensor is giving weird readings to the ECU, since the sensor is downstream of the crack. The pinging started the exact second the headers cracked, so I'm assuming it's got something to do with that.