Here's a Dyno graph of an evo Stage IV 996TT. Someone had mentioned that the car seems to be detonating at roughly 4300rpms (see below).

Im by no means an expert when it comes to analyzing dyno graphs....so, can stephen, todd or anyone else comment on this?

His comments were....

"Although impressive, the car looks to be detonating with that gas. I'd try improving the octane with some racegas or lowering boost so the motor/head gasket doesn't go "caput". By the looks of it that octane is good for not much over 450whp on that particular car. At full boost (~4300rpm) lines start to break up so you get little spikes,which could indicate knock sensors kicking in, or spark issues. At least by adding octane you can eliminate that possibility:if it smoothens out then that boost is probably a tad too much for pump gas,especially when pulling hard multiple times/multiple gears (ie track).

 

The Stage IV is not detonating. What you are seening is an actual dyno graph over the complete rpm range (versus 100 or 500 rpm increaments). The ecu is making constant adjustments in addition to the vario cam going to the next level. It is actually a very good afr over the rpm range given the turbos being worked with.

 

Very decent looking curves. Nice

 

The other thing you are seeing is the rollers loading and unloading. The 248C will do this type of curve on any high HP turbo car. The AFRs are very low with this stage. The avg AFR depending on gas etc is about 12.2-12.5 on this kit.

 

i like afr's like that Why risk anything higher if you don't need to.

 

Porsche likes them low, so why change a good thing Called insurance.

 

that and maybe 50k miles

 

Hey, where did that dyno come from? That was a car we did a while ago. Whos was it???