Gear ratios

Having played with the G-tech device and done some 0-60 runs I am a little annoyed that I cant reach 60 in 2nd...another gear change must bump my time up by 1/4 of a second........I have been chatting with another GTA owner who hits 60 in 2nd. I was under the impression that all GTA gearboxes had the same ratios...is this not the case??

Pete, what are you hitting at the top of second then? When you done a 5.5 to 60, was that with three changes? What revs are you going up to. At 6000 rpm with your size rear tyres you sould be hitting 62mph

The speedo shows about 50+ mph when I hit the limiter. I only got the speedo working again today (bypassed the crappy Renault multi plug and wired the individual wires together) and didnt have the G-tech in the car. I think I had to make a third gear change to hit 60 with the G-tech on.....I will double check tomorrow.

I was told that there are 2 different rev limits on the cars, 6100 and 6500 obviously if you have a 6500 one its easy to get to 60 in second without bumping into the limiter

Theres only been one rev limit of 6100, and the A610s have a limit of 6300, it may just be you still have a slow or lazy speedo. With the 255-40-17 rears and even hitting the limiter at 6100, you should be doing about 64mph

Pete, end of the day, whatever speed the G-Tech says when you hit the rev limiter in second, its over 60..so you may find your real 0-60 is better than the 5.5 you recorded with the G-Tech, which would be pretty impressive!

[simontaylor]

I have no idea how accurate the tacho is, but when I drive mine on the rev limiter it is recording 6300 and the speedo says 60 in 2nd. I'm sure I saw a thread a wee while ago when DG mentioned that early cars had a different ratio, mine is an August 86 car.

Thats about right for yours running the standard rear tyres. Some of th early turbos had non turbo boxes, but this only affects 4th and 5th, not the overall final drive.

[simontaylor]

David, your previous post says that the limit is 6100. The solid red comes on the tach at 6100, ok, when accelerating the limiter first bounces in at about 6100,ok, but when I continue to drive on the limiter, it settles at 6300. Is this normal?
I do suspect that the tacho is lazy, but not as lazy as the speedo.
Simon

The limiter should be 6100, but the A610 has what you say 6100 in first and 6300 for all the rest, so maybe the GTA had this but was never disclosed. Either way peak power is meant to be around 5750, so theres not much point going far beyond.

I can reach 60 in 2nd which is how I managed the 5.5 and other similar times. I hit it just as the limiter comes in.....I had started to change up early for some reason....no wonder my times had fallen to the high 5s/low 6s area!
I will be using the thing at Croft on Monday where conditions (providing its not wet!) will be condusive to getting a good time.

[simontaylor]

I have calculated my speed in 2nd on the following assumptions.
Jacked up the car and measured 1 circumfrence of the tyre, standard tyre 255/45/15, 1.89 meters whilst sreching the tape measure.
Assume max revs are 6100 RPM
60 Mins in 1 Hr.
2nd ratio is 2.06
final drive ratio is 3.44
Overall gearbox ratio (2.06*3.44) = 7.0864
1000 M in a Km
1.98 * 6100 * 60 / 7.0864 / 1000 = 97.6 kph = 60.66 mph (1.609 k:m ph)
So I should reach 60mph in 2nd, but only just, and it would be a bit easier with a little more tread on the tyre or if the rev limiter was a couple of hunderd more. 6300 theoretically would be 62.6 mph.

If my dodgy froggy dials are correct I hit 60 in second at around 6000
I am running 17" rears.Having said that I quite often get readouts of
160 whilst stationary

I have calculated my speed in 2nd on the following assumptions.
Jacked up the car and measured 1 circumfrence of the tyre, standard tyre 255/45/15, 1.89 meters whilst sreching the tape measure.
Assume max revs are 6100 RPM
60 Mins in 1 Hr.
2nd ratio is 2.06
final drive ratio is 3.44
Overall gearbox ratio (2.06*3.44) = 7.0864
1000 M in a Km
1.98 * 6100 * 60 / 7.0864 / 1000 = 97.6 kph = 60.66 mph (1.609 k:m ph)
So I should reach 60mph in 2nd, but only just, and it would be a bit easier with a little more tread on the tyre or if the rev limiter was a couple of hunderd more. 6300 theoretically would be 62.6 mph.

Answers a few questions on various press articles about 0-60s on the Alpines. Factory 0-62 is 7.05 seconds yet 0-60 is 6.1 (though Autocar recorded a 5. which accounts for the extra gearchange, or maybe they tested cars with the slightly narrower 225-50-15 which lowers the overall gearing slightly?..

Ive also heard a couple of things about the atmo GTA. Factory 0-60 is 7.5 seconds but this is with the millemetric tyres...I have a customer in the Netherlands who told be he has a test article with a GTA running the factory available upgrade of the V6 turbo wheels and tyres and recorded a 6.6 to 60! I do remember with my old atmo, I could pull runs in the high sixes quite easily...