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Guest · Posted: Mon Mar 15, 2004 9:18 pm Post subject: lower ratios

i have a 1990 33 cloverleaf that has had an engine swap to the 1.7 16V with electronic injection.
i want to swap the gearbox for one with lower ratios so i can get faster acceleration...i see the smaller engine cars have lower ratio gearboxes but i wanna know if anyone has done this swap and which one i should be looking for...
anyone offer any other tips for better acceleration!

alfistjen · Alfasud Joined: 30 Jul 2003 Posts: 59 Location: Belgium

Hi,

the 1.3 - 1.5 engines have the same ratio's in the gearbox but the differential ratio is shorter so it jumps off faster. You'll just have to live with more and faster shifting and a lower top speed. And I've heared a couple of times that these short boxes dare to split open when driven hard with the 16V engine. But not pretty sure in how far that's true.

Regards!

Paul D.

Guest · Posted: Tue Mar 23, 2004 8:11 pm Post subject:

anyone else heard about these lower diff ratio boxes blowing up when pushed harder?!?!?

Matt Stolton · Posted: Thu Mar 25, 2004 2:34 am Post subject: On the contrary...

Because of the lower final drive ratios, the road has less leverage on the transmission, clutch and eventually engine, so stresses on these components would be lower.

What could cause them to come unstuck may be the extra power has more effect, than the reduced effect of the road on these components.

Seeing as the 16V box and the 1.7 8V box are near as damn it the same box, I doubt the extra power was completley to blame. I would guess a too sticky clutch or rubber, or maybe even larger rims/tyres aided to load the transmission to a point where it popped.

I ran a 1.5 box on my last 1.7 8V, with very few problems, but lots of returns, re acceleration. I also had 195/45 R15 Yokos, which are slightly smaller averall than normal, and regularly torque steered the car, without any dodgy noises from the box. The 8V engine was tweaked to about 130BHP, so not disimilar power, but with more torque than the 16V. If it can survive that, and my style of driving, it should be fairly robust.

On my current p4 project, we are toying with the idea of getting a s1 1.5 4x4 set of diffs, and playing with that, to see if I can get acceleration up a bit, and to lessen some of the load on the clutch and gearbox. If it happens, I will let you know.
_________________
Regards

Matt

Ex Alfa 33 'GTA' (P4 with Knobs On)
Now cruising in a 166 3.2 Ti!!

Guest · Posted: Sat Mar 27, 2004 12:22 pm Post subject:

i currently have a set of 16inch alloys with some fairly hard falken tyres on them but they are really low profile think they might be 205/45's.... what car should i be looking for at the scrap yard to donate its gearbox?!?! sorry i know these might seem like dumb questions but i have never owned a 33 before!

alfistjen · Alfasud Joined: 30 Jul 2003 Posts: 59 Location: Belgium

hi matt,

been through my drivetrain courses again, indeed the stress on the gearbox doesn't get heavier, but it doesn't get less too. Torque only gets stronger after the diff so the gearing itself shouldn't mind. So if the gearbox is the same as the other engine types it shouldn't bother. It is possible as it's only the diff that is different in the gearboxes. Only thing that get's more torque against it's theet is the driveshafts, but can't imagine that alfa made a difference in those. Maybe the gearboxes are of same strength as the others and the guy I know drives the 33 as a porc drives a unicycle... never been with the guy in a alfa, wouldn't want to either.

Regards!

Paul D.