if you want to keep your clutch intact.

Tried a 2nd gear start, at around 2500 rpms...just enough to keep the engine from bogging...and apparently enough to roast the clutch.

But, given a 1-foot rollout, I posted a 12.4 @123.1. The 0-60 was 4.38 and the 0-100 was 8.55. Still lots of room for improvement in my shift times. And on top of wider tires I probably need a better clutch.

 

Pretty good MPH there. Id bet you could see some mid 11s

 

Yeah I think so, once I get stickier tires so I can start out in 1st gear without sliding all over the place. I'm not planning on doing the 2nd gear start again...it's just too tough on the clutch. And if I have to replace the clutch soon, I'm going to go with something stronger.

There's still about 1.2 seconds of dead space in my shifts that I can improve on, even with just 2 shifts. And the 60-100 time of 4.17 and 60-120 time of 7.65 are the best I've gotten. No more testing until I get new tires on.

Here's the speed vs. distance graph of the same run.



It's tough to see the scale, but the zero point is 31887.5 ft and the end point is 33207.5 ft.

 

I think that your car need gear ratios similar to the ford Gt first gear has to go all the way to 60mph etc etc.

 

Your car is great the way it is don't get me wrong.

 

Yeah I agree with you...I have looked at the possibility of going with a lower final drive ratio, but there isn't one available that I know of. Ideally I'd like to be able to get to 60 in 1st gear...then getting the 0-60 time under 4 seconds would be easy.

With the next set of tires I'm going with 325/30 rears which are not only wider but a bit taller and will give me a slight lowering of my final drive ratio. It's only enough to get to 48 or 49 mph in first gear instead of 47, but at least a little bit of a step in the right direction.

 

Tahoe M3, do you still have the original clutch installed? The reason I ask is the clutch on MY08 V8V failed at about 9,000 miles, as I discussed about 7posts down in this link: https://www.6speedonline.com/forums/...urple-oil.html

Aston Marin replaced it under warranty with an upgraded clutch, I think from a MY09 V8V that has the 4.7L engine. I hope my failure doesn't indicate a problem with the earlier clutch--I understand the newer one has a different pin arrangement.

 

I thought the clutch for the 4.7L for '09 and beyond is not backward compatible??? Anyone?

 

Correct, I confirmed this at my local AM service center

 

Yes that's correct I have an aftermarket clutch.

 

I took advantage if the crisp weather this morning to do some runs and got some nice results...the car really likes the cool weather!

60-100 4.00
60-120 7.20
62-124 (100-200 kph) 7.50

 

I think it's interesting to "zoom-in" on the beginning and try to make sense of what's happening. You have already reached 15mph within 12.5 feet (about the length of the car); amazing. With the starting RPMs around 2500, the clutch and tires probably continue slipping, keeping the RPMs up and feeding lots of HP to the rear wheels, until you reach about 30mph (3000RPM) where the clutch and tires finally become fully engaged (the curve becomes a straight line). Interesting!

 

Not bad for a second gear start, huh? The 60 foot time on that run was 2.2 seconds, which isn't bad but isn't good, either...it's sure better than what I was getting when I was starting out in 1st though. Just think what I could do with a good first gear launch and a 1.6 second 60 foot time!

 

I definetly would go to a taller final drive (numerically lower). I think you will see better gains by working on speeding up shifts.

A taller final drive may allow you to do 60 in first but at the expense of rate of acceleration.

I dont think the vehicle has the power just yet to worry about stepping down in gears.

If your worried about a 0-60 performance I would run stickier tires and work on the shifting.

I think these things come with a 3.90 or 3.91 out back and have a very short 1st gear (3.15), comparitevly most T56s have a 2.6 1st gear, and in order to achieve 60 mph with the stock 26.6" tires you have to step quite a ways down (if you arent increasing RPM, my calculations where assuming you where shifting around 7500 RPM) probably below a 3.23 which would greatly impact performance in the rest of the gears in a bad way.

Youve also got a pretty big gap between 1st and 2nd (3.1 to 1.9 for comparison sake the T56 for the Fbodys goes 2.6 to 1.8) so with the lower gears you may even be falling out of the powerband on the 1-2 shift.

Normally I like tall gears on boosted motors but I think your pretty good where you are.

My apologies for the comparison of astons to old camaros thats just what I know.

 

I looked at your graph and I dont see a time scale only distance and speed, so I cant give you any tangible numbers but when looking at elapsed time normally one tenth off the 60 foot is worth almost two tenths off et at the 1/4 mile mark.