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.

 

Sorry, no info for you, but I considered the same mod when I had my V8V. Really curious to hear how it affects the car. Be sure to post your impressions if you move forward.

 

Changing to final drive unit, requires the gearbox to come apart. If you have an SS car, this maybe a pain to do.

 

Why? There are so many other mods you could do, this is by far the hardest & most complicated mod you could possibly do.

What are your fundamental modding goals? Perhaps that's the first question you should answer and then go from there.

 

I don't know about the difficulty involved, but I think it'd be one of the most effective mods to assist with acceleration in terms of cost. Personally, I don't care too much if my car would only do 160 instead of 175.

 

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).
Only thing is by doing this you will lower your max speed..hehe but I doubt you care for the need to do 190mph, and be lowered to 180mph..etc...if this is a concern just raise your rpm range with a tune

After doing this kind of mod on my car, no regrets!! Most cars you have to change or mod the speed sensor output, but on vantage v8 I believe the input is from the ABS sensors, so no mod'ing will be needed by you..just change the final drive gears and your good to go.

I have never done this on a V8V, but don't see it as a hard challenge, the trans can be pulled in 1-2 hours by you, split the case and change over the gears(set gear backlash to spec), then reassemble..

 

Well there you go! Good thing Montreal is a short drive from NZ!

 

Indeed. If another forum member hadn't scared me with the notion that an incorrectly formed gear will create lots of whine, I would've done it. Maybe it's good I didn't try this though because it forced me to get the V12V.

 

The whine that ppl get is from a bad install or very cheap gear set..usually it's the install and the backlash is either to close or to far out.

But even your V12V could have a nice feel with upgraded gears, going from your 3.70:1 to 4.55:1 is nice!! Wouldn't be surprised if you manage to lift a front wheel by just adding slicks to the back after a gear change!! Imagine a Vantage doing a wheelie at the track!!

 

Haha, don't give me any ideas!

 

It depends on the type of use you plan for the car, but the big negative for me would be the increased rpm at a fast cruise on a longish trip.

 

In normal cars yes, on the vantage NO WAY. The gearing spacing is already way too narrow with such a narrow power band. Not to mention highway cruising would be annoying and your gas mileage would be absolutely abysmal.

It will completely ruin the character of the car and I promise you will regret it. But, it's your money, if you want to do it it's your choice, I do not recommend it at all. There are much better ways to improve the performance of the car

 

I'm not convinced it would really be that negative. Yes, a bit higher revs on the highway, but the revs are already really low in 6th gear unless you're over 100, which is probably not that often or too long. As for gas mileage, this is not a car you buy for good gas mileage! If I still had my V8, I would consider this. The positives outweigh the negatives IMO. Anything to help acceleration, the weakest point of the car, would be useful.

 

I put this together some time ago when we were looking at ratios. I don't think it is going to read as well pasted from Excel, but it shows the affect on RPM at a given speed in the top to gears for a series of final drive changes.

For reference, if you call 80MPH cruising speed, you will be bulling 3073RPM on a standard car, 3577RPM with a 4.55:1 final drive. That is roughly the same as going from 6th to 5th gear in a standard car. So it really comes down to personal preference. If your car is a DD or a commuter and you have a loud exhaust it might not be right. If it is a weekend car and you take it off the highway a lot, probably not an issue.

I think running out of gears at the top end is a non-issue. If you are tracking the car on road courses you are not going to run out of gears. Even doing a standing mile, a totally bone stock Vantage will run low 150's (fastest I've seen is a 154), a 4.7 maybe high 150's. Unless you supercharge it, even with a normally aspirated power pack and a final drive change you might *just* touch the limiter in 6th gear at the end of the mile.




3.909:1 (Original Car) 4.11:1

60 MPH 100 MPH 60 MPH 100 MPH 5th (0.935:1) 2780 4634 2923 4872 6th (0.775:1) 2305 3841 2423 4039 Max MPH (RPM) 178(6837) 178(7189)
4.33:1
4.55:1
60 MPH 100 MPH 60 MPH 100 MPH 5th (0.935:1) 3080 5133 3236 5394 6th (0.775:1) 2553 4255 2683 4471 Max MPH (RPM) 171(7276) 163(7288)

 

I'd agree with Stuart on this, the rev's on my car when switching to a 4.10:1 final up from a 3.06:1 was just about 600rpm, as you can see in the ratio mine was just over a full rotation upgrade, it actually made 5th gear more usefull.

Gears are one of the most overlooked things ppl ignore when modding there cars!!

Stuart, have you done this on any V8V's yet, and did you have to do anything else..aka tune the software..or just slap the gearing in and your good to go??