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Date Name Message
08/08/2002 10:33:00   Jason   Anyone know where I can get different ratio gearbox ring and pinion sets for V4 gearbox? I am building a 1850cc engine for my 95 and the standard box will be a little short for the engine power. I need more top speed and less acceleration. I've heard of a chap, Chris Partington I think, who does V4 sports boxes. Anyone have contact details?  
12/08/2002 17:22:00   Alex   Most of the time the sport boxes have shorter ratios instead of longer. The Swedish Saabclub was working on a rack/pinion combination that would even be longer than a Sonett final drive. At present I can't find their website (they moved the address) but is should be ready by now if everything has gone to plan.  
13/08/2002 18:17:00   Jason   Do you know what the sonnett final drive ratio is? Where can I get a Sonnet final drive?  
23/08/2002 08:00:31   bill rawles   I've been thinking about this as well and have had the calculator out!

The standard final drive is ratio 8/39 or 4.88 to 1. This gives a top gear of 17.4mph per 1000 revs.

The Sonnet final drive is 9/42 or 4.67 to 1. This gives a top gear of 18.2 mph per 1000 revs.

I do not have experience of a 95/96 with the sonnet final drive but it hardly seems worth the bother for such a small gain.

Think of it this way, drive your car at 70mph, I dont know about your car but my 96 is pretty noisy at that speed, the engine is at 4030 revs. Now slow down to 67mph, the engine is at 3850revs, with the sonnet final drive you will get 70mph for this engine speed but I bet you cant really tell the difference!

Having said all that I will put a sonnet final drive in my own car when I get round to rebuilding the gearbox. If you are rebuilding a gearbox anyway then its worth doing but I personnally would not take a serviceable gearbox out just for this.

I reckon going to about 4.5 to 1 would be about right which would give 18.9mph per 100 in top (70mph at 3700revs) but it would probably involve having a ring and pinion specially made which is very expensive even if it is possible to change the gear sizes this radically.

I'm willing to be corrected on all these figures by the way if anyone wants to get their calculator out!

Motorsportsweden can be found on the links from this website.

I've seen the name Chris Partington mentioned as being a gearbox guru and would also be interested in how to contact him if anyone knows.  

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