Final Drive ratio change AM V8
#31
06-05-2012, 03:10 PM
I am considering changing the final drive ratio of my Aston Vantage V8 2007. Anyone out there changed theirs (crown wheel and pinion change)? RSC are offering a 4.55:1 aftermarket set. Anyone purchased this specifically? Also feed back on labor times for the change would be appreciated.
The only problem I had, I was the first to buy the kit from Stuart and there were problems of precision parts which brought the noise in the rear transmission. I'm doing tests on my new, but as soon as possible, I will put the kits on my new rsc. With the transformation of Bamford and Rose Stuart of this kit, we made the calculation that the 0-100 km / h should be under 3.5 sec. On the gray, I had improved from 80 to 120 km / h for more than a second (3.2 sec, if I remember correctly)
The link on my website: http://vantagev8.e-monsite.com/pages...ge-clutch.html
Last edited by vince_1972; 06-05-2012 at 03:16 PM. Reason: link to my website
#33
06-05-2012, 04:20 PM
Curiously, I've been looking at the maps in the AMV8 ECU and we never get wide open throttle until 5K RPM. There is a 2D map throttle overrider that limits max throttle opening vs RPM which is independent of accelerator pedal position! Same on Mustangs and a common thing to change I believe.
If you don't believe it, datalog your OBD2 with RPM and relative throttle position(%) and go WOT.
If you don't believe it, datalog your OBD2 with RPM and relative throttle position(%) and go WOT.
https://www.6speedonline.com/forums/...g-100-wot.html
#34
06-06-2012, 01:03 PM
You are correct, a rear gear change "is the best bang for the buck", racers have been doing this mod for YEARS!!. I myself have done this to my own car, I don't own no Aston, but I do own a Mustang, going from a stock final drive of 3.06:1 to 4.10:1 gave me a full second on the 1/4 mile. You will not gain any power or torque but rather just shift the power/torque band to a lower more usable range..so say instead of hitting max torque at 4000rpm you will now achieve it around 2,000rpm(just estimated numbers).
First of all, gearing changes do NOT change the RPM at which peak power/torque is achieved. It merely multiplies the torque more to the wheels, in this case, making 6th gear numerically equivalent to the stock 5th gear.
Anyone who is contemplating this needs to cruise on the highway in 5th for a while to see if they could live with this. My answer is absolutely not.
Torque at the tires increases, but it would require intake/exhaust changes to alter the powerband, as you have incorrectly stated above.
As a veteran 5.0 Mustang fan, I've done the old 2.73 to 3.73 swap for $500, and it did make a big difference, but the Vantage is already geared very short, and considering that a gear swap would cost more than the purchase price of my LX notchback in 1994, it is hardly the "bang for the buck" proposition that it would be on a 8.8" Ford rear end.
As Stuart has noted, $10k would be much better spent on exhaust, or maybe a down payment on a TVS blower.
Sorry if this sounded harsh, but I hate when misleading info is propagated here, and I didn't see any posts pointing this out.
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