Modifying gearboxes?

[Anonymous]

nearly got all my bits together to fit my GTE engine in on twin carbs, but I have one question....
If I buy a GTE gearbox, take it apart and then put in the gears from my 1.4SR gearbox will this make any noticable improvement in acceleration, or is it not really worth doing?

[Anonymous]

If you did that you would lose top end speed i would have thought, and it wouldnt be that much better on the acceleration,

[Anonymous]

Depends on a few things. If you have the close ratio box with the GTE which you should have, the ratio's will be the same as the 1.4sr, some however don't and are longer, so fitting the closer ratio's from the 1.4 along with the final drive from the GTE will give much better acceleration through the gears upto 130mph at about7k rpm in 5th.

You will not loose top end speed, as with engines like these, your top speed is governed by how powerful the engine is, not the ratio's as most cars can't rev out in top gear.

I'll give you an exaple from my car, and my clocks are pretty accurate against rolling roads;

Original 1.6 gearing (long ratio);
4th; 130mph @7500rpm
5th; 130mph (no more power, but some silly theoretical top speed of 170mph!)

1.4 cluster with GTE FD;

4th; 105mph @7500rpm
5th; 130mph @7500rpm (exactly the same ratio's as previously 4th gear)

The change up from 3rd to 4th was the biggest improvement, but I can't remember any speeds. The car is much quicker from 30mph through to 120mph now.

You might already have cloe ratio's though, and the only real way to tell is to drive it. The clusters can be changed with the gearbox in the car.


**Why take a big block on the track when you can whoop ar*e with a small block?**

[Anonymous]

The tightest/lowest ratio (as mc says) gives a far more satisfying gear change and if you like to use your gears and push the car on its well worth it. The word I would use is "sporty". If you like to cruise at speed at lowish revs without ragging about changing gears then don't bother.

[Anonymous]

Its also possible to get hold of a 4.3 or 4.5 CWP (Final Drive) which will lower the ratios even further, and bring them closer together. The standard ratios are known as 3.7, 3.9, and 4.1 but there are odd F10/s and F13 boxes out there with the others (Swedish post office Nova vans have 4.5 CWP!)

However, with a 4.5, youre top end will be close to about 105mph so its not ideal for cruising on the motorway (but you will get there quicker!)