| Metal Timing Gears Standard Saab Taunus V4 timing gears are Nylon/Fibre. These can wear and can fail. I am not sure when it can happen but do know that increased stresses on the engine will only expedite this process. It is always a good idea to keep an eye on these things and check regulalry. I may have gone overkill but have put in a set of Metal Timing Gears, being much stronger and longer lasting. They are, howvever, noisier than the nylon gears. These are rare as rocking horse poo. I must say thanks to Alex who got them over from the Netherlands for me. |
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| Engine - Part 2 |
| Gear boxes There are two broad areas for uprating the standard gearbox: Fast Road or Rally. Either way, it costs big money, not due to the technology, moreso due to the rarity of parts. Rally is not my speciallity but I can tell you that during the 1970s Saab released two types of Rally Gear box with four gear combinations. The gear boxes were much stronger than the standard casing and particulaly necessary for anything over 120bhp - that said, I know of at least one person whos 130bhp 96 uses a standard gearbox, but he does so because he treats is with respect. In terms of road performance it is the casing that is important. If you plan to increase you bhp up to or over 120 and you find one of these, get out you chequebook. One alternative is the nearly as rare 2 stroke gear box being stronger as it was cast iron. This also equates to heavier and it has a poorer lubrication system compared to the V4. The V4s also had two types of box; the early version was smother and weaker. The later version is ribbed and stronger. Expect to pay �450 for a good ribbed gearbox. |
| Gear Ratios This is where speed is unleashed, but again, at a price. The standard final drive (Crown and Pinion) is a ratio of 8:39. There is a Saab Sonnet final drive of 9:42. Harder to track down and also allegedly weak, so must be treated with respect. Now we are into the realm of myth and legend... There exists a rare aftermarket 9:36 final drive, much larger than the standard but because of its size, the drop gears in the gearbox must be replaced with drop gears from a Spec 2 rally gearbox (this does, however, reduce the gear ratio). Ouch, thats is gonna hurt the wallet twice. If it is maximum speed you want, this is for you but don't expect to find it in Halfords. Legend has it that there are some plans to produce a 9:38 final drive that will fit straight in to the standard box (or rally box if you are really lucky). These are plans. I do not want to give out names and contacts for fear of upsetting the poor fellow at the source, but feel free to contact me for more information. What does this mean? The follwoing table shows the gains possible (in fourth gear). The gains are modest while ticking over but with your performance cam, ported heads and stiffer springs (which you will of course have before investing in an alternative final drive!), allowing you to achieve upto 5,000 rpm, the gains become significant: Cruising along the motorway at 70mph will have your std engine straining away at over 4,000 rpm. The Sonett 9:42 final drive frops this to below 4,000 rpm. The Uber-Drive drops this to below 3500rpm. Prrrrrrrr. |
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| RPM Comparison (mph) (4th Gear) 30 mph RPM Comparison (4th gear) 8:39 9:42 9:36 9:38 8:36 9:42 9:36 9:38 1,000 17.31 18.10 19.19 20.0 1,732.85 1,655.17 1563.52 1499.01 2,000 34.63 36.25 38.38 40.0 3,000 51.94 54.38 57.56 60.0 70 mph RPM Comparison (4th gear) 4,000 69.25 72.50 76.75 80.1 5,000 86.56 90.63 95.94 100.1 8:36 9:42 9:36 9:38 6,000 103.88 108.75 115.13 120.1 4,043.32 3,862.07 3,648.21 3,497.70 |