Questions about the Tremec 6 speed?

[Dawgfan]

Has anyone tried the 6 speed Tremec ???????????????

[panozls1]

Originally Posted by Dawgfan

Has anyone tried the 6 speed Tremec ???????????????

I have the 6 speed in a Penske Panoz. I am struggling with the gearing in the car. The first two weekends I used the car I noticed the car was "lugging" in 4th and 5th gear most of Roebling Road. No way to use 6th gear. I checked the rear end today and find that the rear gear is a 2.00 ratio. Anyone got ideas what to do to fix this problem.? My first idea is to change the ring and pinion to something around 3.5 or 4.

[Gatorac]

The t56 has a 1-1 4th. A .8 5th and a .6 6th. The road race 3550 has a 1-1 4th and a .8 5th. There really shouldn't be any need for the extra gear. The thing is a tank too. Really heavy.

[NZGTRA17]

Originally Posted by panozls1

I have the 6 speed in a Penske Panoz. I am struggling with the gearing in the car. The first two weekends I used the car I noticed the car was "lugging" in 4th and 5th gear most of Roebling Road. No way to use 6th gear. I checked the rear end today and find that the rear gear is a 2.00 ratio. Anyone got ideas what to do to fix this problem.? My first idea is to change the ring and pinion to something around 3.5 or 4.

Are you absolutely sure the ring and pinion ratio is 2:1 ? This is an extremely unusual ratio to fit to a track car especially in conjunction with a heavily overdriven 6 speed. If it is 2.0 to 1 a change to 3.9 is certainly warranted.

Actual selection (3.5 Vs 3.9 etc) should be based on the track/s you will most frequently race on. I have a great gearing/speed calculation spread I can share with you if you want to work out the best ratio. PM me with your E address if you want this spreadsheet.

Kel.

[Dawgfan]

Please share. I have been talking to a guy at Rockling Gear and he told me that he can make any ratio I need. I run at Road Atlanta more than anywhere else. A 2.5 mile, up and down hills. A great course. Google it and you can see the layout.

[Panoz26]

Originally Posted by NZGTRA17

Are you absolutely sure the ring and pinion ratio is 2:1 ? This is an extremely unusual ratio to fit to a track car especially in conjunction with a heavily overdriven 6 speed. If it is 2.0 to 1 a change to 3.9 is certainly warranted.

Actual selection (3.5 Vs 3.9 etc) should be based on the track/s you will most frequently race on. I have a great gearing/speed calculation spread I can share with you if you want to work out the best ratio. PM me with your E address if you want this spreadsheet.

Kel.

David - Kel's comments are dead on - a 2.00 is very odd, especially for the Penske cars. How did you validate the finding?

Devin

[panozls1]

Can you determine the ratio by counting the revolutions of the drive shaft vs one rotation of the rear wheel? That is the method I used. Am I off base?

Originally Posted by NZGTRA17

Are you absolutely sure the ring and pinion ratio is 2:1 ? This is an extremely unusual ratio to fit to a track car especially in conjunction with a heavily overdriven 6 speed. If it is 2.0 to 1 a change to 3.9 is certainly warranted.

Actual selection (3.5 Vs 3.9 etc) should be based on the track/s you will most frequently race on. I have a great gearing/speed calculation spread I can share with you if you want to work out the best ratio. PM me with your E address if you want this spreadsheet.

Kel.

[NZGTRA17]

Originally Posted by panozls1

Can you determine the ratio by counting the revolutions of the drive shaft vs one rotation of the rear wheel? That is the method I used. Am I off base?

You can use this method David but you need to be very accurate to get it right (i.e. 3.7 Vs 3.9). I normally remove the nugget and count the pinion Vs crown wheel teeth and calculate from there.

Kel.

[PanozDuke]

Originally Posted by NZGTRA17

You can use this method David but you need to be very accurate to get it right (i.e. 3.7 Vs 3.9). I normally remove the nugget and count the pinion Vs crown wheel teeth and calculate from there.

Kel.

Kel,
Is nugget what we call the chunk, pumpkin and/or third member? Is the crown wheel what we call the ring gear? Just want to improve my fluency in Kiwi

Mike

[NZGTRA17]

Originally Posted by PanozDuke

Kel,
Is nugget what we call the chunk, pumpkin and/or third member? Is the crown wheel what we call the ring gear? Just want to improve my fluency in Kiwi

Mike

Nice one Mike.........actually I borrowed nugget off you guys. We normally call this the diff center or crown wheel & pinion. Yes crown wheel is the ring gear.

I cant use Third Member, just makes me laugh to much I am afraid. I assume the first member belongs to the driver.............?

Kel.

[boothkc]

No need for 6 speeds...too much shifting and who needs 2 overdrive gears? I guess if you had some amazing 8000 rpm car and 4:56 gears or something like that.

We run the 3.5 or 3.89? in the GTS and don't use 5th with 3.5 end up in 5th with the 3.89 at the end of our straight. Lap times were better with fewer shifts using the 3.5 rear, but your track may do better with more shifts if you have big elevation changes (eg Infineon or Laguna) and crazy long straights. For most of us this is a subtle performance gain area.

Certainly, I can't imagine needing 6th as I almost never get into 5th.

Kevin

[Panoz26]

David, I found this -- might help:
Ford 9 inch differential with True-Trac. Final drive ratio: 3.50:1 or 3.89:1

It's from a file I downloaded on the GTS SCCA Spec Sheets -- I would assume the Penske cars met these guidelines.

Ill email the doc to you.
Devin