quote:Originally posted by stephen:
... my question is to anyone running a 3.22 with a motor of about 450bhp, is the performance adversely affected ...
Steve you won't find too many people running that gear, so don't be surprised if you aren't answered.
The answer to your question also depends what you mean by "performance". Acceleration? Yes acceleration will be worse.
Top speed? If your motor develops maximum bhp at 6000 rpm, then you will hit peak bhp at 170 mph in 5th gear with the 3.77 gear set and the standard 5th gear. (The Pantera's handling gets pretty squirly at higher speeds unless you drop the nose of the car very close to the ground AND modify the suspension to increase the caster.)
As you install higher ring and pinion gear ratios (smaller numerically) the rpm spread between each upshift becomes greater, effectively giving you a wider ratio transmission. My fear with the 3.2:1 ring and pinion would be that the ratios would be too far apart, and you would fall off the power band with each up shift.
3.2:1 also sounds a bit boring to me, from the point of view of acceleration.
Jeff makes a good point, the higher 5th gear is a good upgrade for travelers. Regardless of which ring & pinion you choose. RBT offers 0.655:1 and 0.642:1 5th gear sets, stock being 0.70:1.
I calculate your motor currently turns 2810 rpm at 80 mph (130 KPH) in 5th gear, assuming you have a rear tire of 26" diameter.
(1) add the 0.642 5th gear, 2570 rpm at 80 mph, a reduction of 240 rpm.
(2) add the 3.2:1 ring and pinion, 2380 rpm at 80 mph, a reduction of 430 rpm.
(3) add both the 3.2:1 ring and pinion and the 0.642:1 5th gear set, 2180 rpm at 80 mph, a reduction of 630 rpm.
My numbers are rounded off.
On one hand you have fuel economy, and the needs of comfortable long distance traveling. On the other hand you have acceleration performance and around town performance. The decision is what is the best compromise for you.
My advice would be to keep your current ring and pinion and install the 0.642:1 5th gear set, as the best overall compromise between long distance comfort, fuel economy and performance.
For the US members:
On a US Pantera, installing the 0.642:1 5th gear drops the motors speed by 270 rpm in 5th gear at 80 mph (26" diameter rear tire), from 3140 rpm to 2880 rpm. This is good bang for the buck, that's why Lloyd recommends it.
Installing a 4.0:1 ring and pinion and the 0.642:1 5th gear set only drops the motor's speed another 110 rpm, to 2730 rpm. Not much bang for the buck.
Installing a 3.77:1 ring and pinion and the 0.642:1 5th gear set drops the motor's speed to 2570, another 310 rpm lower than just the 5th gear change only. That would be good bang for the buck too, for an open road traveler, if the reduction in acceleration performance is acceptable. The car will wind out in each gear longer as you accelerate, and have more of the feel of an Italian sports car, less like a muscle car.
cowboy from hell