optimizing the 997 gearbox (aisin gearbox)
07-28-2010, 04:55 PM
#1
optimizing the 997 gearbox (aisin gearbox)
Hey there everyone,
Just as tuners like to tweek engines, and ECU's and such, we enjoy playing around with the gearboxes to find that little extra edge. What we discovered was that the ratios for the 997 are not quite optimal, so we decided to have a few of them remade for us.
By shortening up the 3rd, 4th, and 5th gear we were able to find just a bit of an edge on acceleration and were really able to equally space the gearbox out for better performance.
The stock ratios look like this: 7000 RPM Redline 25.37 inch dia tire
1st gear 3.9091 39.254 MPH at RL
2nd gear 2.3158 66.261 MPH at RL
3rd gear 1.6071 95.478 MPH at RL
4th gear 1.2813 119.764 MPH at RL
5th gear 1.0811 141.939 MPH at RL
6th gear 0.8837 173.638 MPH at RL
With our revised 3rd - 5th gearsets it looks like this:
3rd gear 1.7368 88.349 MPH at RL
4th gear 1.3636 112.528 MPH at RL
5th gear 1.0938 140.296 MPH at RL
By shortening these up a bit there is less of a drop between gears therefore allowing the car remain in the optimal powerband and accelerate quicker.
I just thought that I would share this with you all, and see what your thoughts were. We will offer these as a kit to anyone who might want it. Not sure what the cost is going to be just yet though. I will have to get back to you all with that if there is any interest in these.
Warmest Regards,
Erik Johnson
GBox Performance Transaxle
(303) 440-8899 work
(303) 895-4828 cell
www.gboxweb.com
Just as tuners like to tweek engines, and ECU's and such, we enjoy playing around with the gearboxes to find that little extra edge. What we discovered was that the ratios for the 997 are not quite optimal, so we decided to have a few of them remade for us.
By shortening up the 3rd, 4th, and 5th gear we were able to find just a bit of an edge on acceleration and were really able to equally space the gearbox out for better performance.
The stock ratios look like this: 7000 RPM Redline 25.37 inch dia tire
1st gear 3.9091 39.254 MPH at RL
2nd gear 2.3158 66.261 MPH at RL
3rd gear 1.6071 95.478 MPH at RL
4th gear 1.2813 119.764 MPH at RL
5th gear 1.0811 141.939 MPH at RL
6th gear 0.8837 173.638 MPH at RL
With our revised 3rd - 5th gearsets it looks like this:
3rd gear 1.7368 88.349 MPH at RL
4th gear 1.3636 112.528 MPH at RL
5th gear 1.0938 140.296 MPH at RL
By shortening these up a bit there is less of a drop between gears therefore allowing the car remain in the optimal powerband and accelerate quicker.
I just thought that I would share this with you all, and see what your thoughts were. We will offer these as a kit to anyone who might want it. Not sure what the cost is going to be just yet though. I will have to get back to you all with that if there is any interest in these.
Warmest Regards,
Erik Johnson
GBox Performance Transaxle
(303) 440-8899 work
(303) 895-4828 cell
www.gboxweb.com
