Where is the 7 speed tranny on the ZL1/ZL1 1LE?
 

Where is the 7 speed tranny on the ZL1/ZL1 1LE? Where is it?

Please explain.

The 7 speed supposedly doesn't fit in the Alpha platform. Plus 7th gear is just a really tall gear meant for highway cruising. There isn't a performance advantage to the 7 speed vs the 6 speed.

I was initially surprised the 7 speed was not offered in the SS, since the Camaro usually gets the same powertrain as the Corvette (after it debuts on the Corvette). I suspect the main reason is that the bigger/heavier/less aerodynamic camaro had more trouble pulling a 0.42:1 7th gear, specifically on the EPA certification cycles. I'm sure the engineers analyzed a benefit (CAFE / CO2) vs. cost and made a decision.

Another factor may have been that the TR6070 is about 1.65" longer than the TR6060 - it's possible it simply did not fit.

I'd be interested in Al and team's feedback on this one, but only after a couple other questions get answered that I consider higher priority.

I agree with what you're saying, but the 7 speed may have enabled them to put a more aggressive rear axle ratio in (4.10:1 for instance) and also hit their fuel economy targets - so it's possible it could have enable some level of performance benefit.

There's not a significant performance benefit to the 7-Speed below ~140 MPH. If you change the rear gear, then the underdrive ratios would have to be adjusted accordingly to maintain drive-ability. In other words, the final drive ratio of the underdrive gears wouldn't change.

I wouldn't want a gear taller than the current 6th gear ratio. A taller ratio would make the engine lug a little too much while using cruise control on the interstate hills. That only leaves room for improvement in 5th gear. Sure, they could get slightly better acceleration beyond 4th gear, but unless you're running on a long straight on the Nurburgring at 140+, when would that ever matter?

I'm perfectly happy with the 6-speed. The benefit to the 7-speed is so negligible I see it as a (borderline) gimmick.

Just my 2 cents... To each his own.

These bad boys are in Porsche’s and Corvettes though. So there is something to be had. I’m sure gearing would need to be changed to make it all work correctly. Once again these parts bin items.

The average speed answer is so slow that it could be 2020 when we get the answer.

The benefit would be you'd get closer overdrive ratios. So looking at the ZL1 1LE, they decided to update the gearing but only decided to go with a little shorter 6th gear. That tells me the ratios for 1-5 are already pretty optimal for this car.

If we were to see a 7 speed, I'd bet what we'd get is ZL1 1LE gearing for 1-6, and the 7th gear ratio would be the same as 6th in the ZL1.

The 7-speed would be slightly better, and I certainly wouldn't be opposed to it. The difference is going to be pretty minor though.

This ^ It's on here somewhere that the 7 speed does not fit in the alpha

So the A10 fits in the Camaro but not in the Corvette. And the M7 fits in the Corvette and not the Camaro? I think I'd need some more evidence to be convinced.

I was comparing pictures of the TR-6060 and the TR-6070. The center sections look nearly identical.
http://www.tremec.com/anexos/TREMEC_TR-6060.pdf
http://www.tremec.com/anexos/File/TREMEC_TR-6070.pdf

Obviously the TR-6070 would need to borrow the bell housing and tail housing from the TR-6060 to make it work in the Camaro, but is there some other problem?

The TR6070 has three slightly different gearsets already. I bet it wouldn't be all that hard to add a fourth that was better suited to the Camaro.

From the Tremec site . . . without doing any math, some of the adjacent gear spacings look to be nearly as close as in the 10-speed automatic.

https://www.mustang6g.com/forums/pic...ictureid=11625


Norm

Good point. I'm not convinced that fitment issues is the reason it wasn't implemented.

The additional gear's primary purpose was for fuel economy. It also has some minor performance benefits in overdrive, but unless you're driving on the Nurburgring it isn't going to make a real difference.

Both transmissions will always have a 1:1 ratio in 4th. So the 3 gears that matter most for performance are gears 1-3. For these gears, any ratios you can put into a TR-6070, you can put those same ratios into the TR-6060. I'm betting the ratios we already have are close to optimal for the Camaro. So including those same ratios in the 7-speed isn't going to provide any benefit.

On the side of fuel economy, the benefit seems to me to be more for gov't fuel economy ratings. Think about it. You'll spend 99% of the time in the highest gear on the highway. When cruising on the highway, most people don't shift much. Whatever the optimal ratio is for cruising on the highway could just as easily be included in either transmission.

Like I said before. I'd have no issue with the inclusion of the 7-speed, but at the same time, I don't think there are any significant benefits either (at least for the consumer).

From GM's perspective, a slight improvement in the fuel economy ratings (not to be confused with real world fuel economy) would probably be worth considering.