Geoffrey

No, it is an unordered list. Engine design and purpose will dictate which strategy I use. For the most part I use Throttle Position and Speed Density only. Right now the car is running on throttle position and I'll be converting it to Speed Density tomorrow and tuning it using that strategy.

Geoffrey

Finished the dyno work today, here is a video of the car on the dyno. With the fabspeed exhaust it sounds like an old SC which is cool. I'm happy with the results so now we just have to finish up a number of odds and ends and road test the car for final tuning.

http://www.racetek-engineering.com/i...Shock Dyno.wmv

shockm

nice.....

Ritter v4.0

What redline are you running with this set-up?

Geoffrey

Since the heavy factory Mahle pistons were retained, the redline is limited to 7000. On the dyno we ran it to 7100 to ensure that we were able to capture data at 7000, but has since been set back to 7000. The heavy pistons will begin to twist the connecting rod after about 7k so that is the limiting factor. The second engine that is going together now has the lighter 9M sport pistons (original version) which allow for the rev limit to be raised to 7100-7200 with stock connecting rods. I'm expecting the second engine to produce about 15-17hp more than this engine due to the full point increase in compression.

Ritter v4.0

Sounds like you are using stock rods. Assuming stock rods, would different/better rods allow you to run higher rpm with the Mahle pistons- is it the pistons, the rods or the combination that is the limiting factor?

Also- do you use the 964 oil pump wit this set up or feel the need to use the GT3 pump?

Geoffrey

Carrillo rods are certainly stronger than stock rods and would last at higher RPM, however, the piston, due to its weight will deform at the wrist pin boss. These engines were not meant for high RPM and you'd want to replace both the piston and rod to run the engine higher than about 7250. (MY OPINION).

The 964 pump is fine for street/DE applications. If I was in the engine and it had a number of miles on it, I would go ahead and replace the pump with a GT3 pump.

N51

Geoffrey,

Could you speak of the differences of the Mahle pistons and the 9M pistons with regard to clearances? Two different metallurgies.

TIA,

Geoffrey

Yes, the Mahle pistons run about .0004 less clearance than the older 9M pistons. There are 4 new 9M pistons in the works which will change what will be offered.