I have a question for those with a GT3.

My question is at what rpm is your sweet spot? Or putting it another way ........... at approximately what rpm does your torque and power start to come on and approximately where does it start to taper off?

The reason for my question is KA's new turbo motor is utilizing the GT3 cams. I'm trying to determine which type of turbo's would best serve tracking/driveability purposes.

 

I have to check again, but it seems that the car really wakes up after 5000rpm. That's when this great trumpet sound starts to fill the cabin with the sweetest sound, and the car starts to pull.

This is of course empirical, and not exactly scientific. It doesn't really seem to taper off, pulls all the way to redline... or maybe it just feels that way.

Sorry I can't be of more help.

Cheers from Paris.

 

Thanks Tyson. And redline is 8100?

 

I believe it's 8200.

 

real power is made at 6500rpm and up

...as speed increases.. the drop in shifting rpm... it lands in the range of 4th...6300...up to 6700+ going into 6th gear.

 

My question is this. We have built a motor based on the GT3 motor, ie. crank, Cup heads, valves (modified inconnel), lifters and cams. The pistons are 9.2-1 compression ratio and thus designed for the turbo motor.

The motor will respond like a GT3 motor (due to cams-no variable lift), abeit with turbo power. We can install turbo's that attain full boost at approx. 2800 rpm's which will develop approx. 900 hp or less (depending on where the boost is set) and go into overboost around 8000 rpm's or we can use turbo's that will develop full boost around 4500 rpm's and develop 1200 or so hp.

Any suggestions from those who have driven the GT3 as to which turbo would be the better way to go for street and occasional track fun days?

 

I was looking at the GT3 dyno chart on the Europipe website. That motor has a pretty sharp upward power curve from 2800 thru 7200 rpm's.

 

tyson,

spoken like a true liberal... why not go drive the car abit, since you have that factory RS wing....

car rolls on cam at 6200 and runs good to redline. gears are way too tall which distorts the enigne's ability

 

I do drive the car plenty. How the hell am I supposed to know if its 8100 or 8200 by the time I hit the rev limiter?

Your "special" RS wing makes the redline 9000

 

My dyno runs show peak power at 7800 rpm. Redline is 8200 rpm.

 

Thanks for the info.

 

Chad,
how come you aren't using cams with a profile specific to a forced induction engine.
The profiles of a na vs. forced induction (lift, duration and specifically overlap) camshaft would have a lot to do with how this vehicle performs.

I cant imagine a GT3 camshaft is optimum for you application.

Just womdering.

PaulK

 

dyno chart

 

Looks like 7300-7500 rpm's is all you really need.

 

I wish it was as simple as that. The turbo uses a vario cam which really isn't conducive to undisturbed power over a wide bandwith. The GT3 is not vario lift. It has vario timing. The GT3 cam has higher lift and longer duration. It will help produce more power with less boost.

The only drawback will probably be a rougher idle.

I don't believe the question is "as to a profile specific to forced induction" as it is to the turbo cam is a cam designed to run well throughout the whole range and therefore compromises all ranges to a certain degree. Remember, these are our opinions. We may be out in left field. One thing is for sure .............. we will find out very soon.