The Gen 5 Gearing versus the Gen 2 Gearing

[Jack B]

The following table should shed some light on the what was done to the Gen 5 gearing. After putting some miles on the car my personal opinion is that the G5 has perfect gearing for road racing and autox. To go one step further the gearing is close to perfect for a daily driver - SRT hit a home run. When you compare the Gen 2 and Gen 5 transmission ratio's you wonder who the hell developed the old scheme and why it was not changed earlier.


With all that said, there is one minor problem, the combination of:

A. A lower numerical 1st gear.
B. A shift of the torque curve upward.
C. A light flywheel.

These all make it difficult to launch the car at the dragstrip, not impossible, but, difficult. The car should perform better with the 26" hoosier, versus, the 27.5 Mickey Thompson.

The table that follows uses normalized numbers and compares the changes in the transmission and overall gear ratios:

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Gen 2 - 3.07 Rear/26" Tire		Gen 5 - 3.55 Rear Gear/**27.4 Tire
Trans Gear	Gen 2 Trans Ratio	Ratio w/Rear Gear Multiplier (3.07)	Normalized Overall Ratio w/26" dia		Gen 5 Trans Ratio	Ratio w/Rear Gear Multiplier (3.55)	Adjusted Ratio w/27.4" dia	*Gen 5 %-Higher/Lower gear ratio
1st	2.66	8.17	8.17		2.26	8.02	7.61	6.8%
2nd	1.78	5.46	5.46		1.58	5.61	5.32	2.6%
3rd	1.30	3.99	3.99		1.19	4.22	4.01	-0.4%
4th	1.00	3.07	3.07		1.00	3.55	3.37	-9.7%
5th	0.74	2.27	2.27		0.77	2.73	2.59	-14.2%
6th	0.50	1.54	1.54		0.63	2.24	2.12	-38.3%
* A higher ratio is numerically lower
** I measured the Corsa and it seems to have a smaller than advertised diameter - I need to measure the tire again to confirm.
RPM Drop
Gen 2 - 3.07 Rear/26" Tire		Gen 5 - 3.55 Rear Gear/27.4 Tire
Trans Gear		Adjusted Ratio 3.07 & 26" dia	Gen 2 % RPM Drop @ shift		Comment	Adjusted Ratio 3.55 & 27.4" dia	Gen 5 % RPM Drop @ shift	MPH at 6000 RPM
1st		8.17				7.61		61
2nd		5.46	33%			5.32	30%	87
3rd		3.99	27%			4.01	25%	116
4th		3.07	23%		< Input & Output shaft coupled >	3.37	16%	138
5th		2.27	26%			2.59	23%	178
6th		1.54	32%			2.12	18%	218

 

[Nine Ball]

Good info, nice work. It would be cool to get all 4 gens data to compare side by side.

I like gears 1-5 in my 2013, but I think 6th should have been a better OD so that it could stay under 2K rpm at 80 mph. Most interstates in TX are now 75 limit, and some toll roads 85 limit. When I can use 6th gear as low as 45 mph, it is just too much gear. Rather not be able to use 6th gear until at least 65 mph.

 

[SilveRT8]

Great info Jack B, but for max speed in gears, shouldn't we get it at the Gen V redline of 6400 rpm ?
Per Drivesrt : Max power 640 hp at 6200 rpm and fuel cut off at 6400 rpm

 

[Policy Limits]

But the V does 60mph in 1st gear so I've had no reason to upshift

 

[Nine Ball]

But the V does 60mph in 1st gear so I've had no reason to upshift

That is how they achieved an impressive 0-60 number. I really hate 0-60 comparisons, and wish companies would move to 0-100 instead. 0-60 was good back when 200 hp was a lot, and bias ply tires were the norm.

 

[Jack B]

Correct, I just wanted to use a number that was easy to work with.

Great info Jack B, but for max speed in gears, shouldn't we get it at the Gen V redline of 6400 rpm ?
Per Drivesrt : Max power 640 hp at 6200 rpm and fuel cut off at 6400 rpm

 

[Jack B]

The overall ratio in 1st is not way different, the light flywheel hurts us the most. Was the G4 a twin disk? I am going to try 26" tires next week.

That is how they achieved an impressive 0-60 number. I really hate 0-60 comparisons, and wish companies would move to 0-100 instead. 0-60 was good back when 200 hp was a lot, and bias ply tires were the norm.

 

[Steve M]

Wait...so you're telling me that 3rd gear isn't 1:1?

Sorry...had to go there.

It's definitely interesting to note the differences between the two...if I ever have my TR-6060 rebuilt, I'll likely consider the .80/.62 5th/6th cluster to make those gears a bit more useful on the highway with the 3.07 rear. I could do the same by just changing to a 3.55 back there, but traction ***** in 1st gear (and sometimes 2nd) enough as it is.

And yes, the G4 is a twin.

 

[Jack B]

By design a twin should be lighter. Do you think the G5 is much lighter. The G5 is sure hard to launch, far harder than my G2 which has 3.55's.

Wait...so you're telling me that 3rd gear isn't 1:1?

Sorry...had to go there.

It's definitely interesting to note the differences between the two...if I ever have my TR-6060 rebuilt, I'll likely consider the .80/.62 5th/6th cluster to make those gears a bit more useful on the highway with the 3.07 rear. I could do the same by just changing to a 3.55 back there, but traction ***** in 1st gear (and sometimes 2nd) enough as it is.

And yes, the G4 is a twin.

 

[Steve M]

According to this video, the Gen 5 clutch assembly is about 11 pounds lighter than the Gen 4:

http://youtu.be/9SZxsSz6cCo

 

[Jack B]

That is good for everything except the launch.

According to this video, the Gen 5 clutch assembly is about 11 pounds lighter than the Gen 4:

http://youtu.be/9SZxsSz6cCo