6 speed vs. 5 speed

[Vip09]

Gas mileage is great in 6th gear!

[kfoote]

Originally Posted by MKIISupra

did you just say that the differance is only 10-20 pounds. It seems like you are saying that is not alought of weight. Well, that is a lotta lotta lotta weight. JGTC guys take grams off of cars, taking 10-20 pounds off is more helpfull than you think. I am stripping my whole entire car, no iterior AC no rear seats no speakers or anything.

For racing, a 6 speed transmission with closer gear ratios for highly tuned engined with a narrow powerband will be faster because it allows more time spent at peak power, which more than makes up for the added weight. If you're trying to remove weight, there are a lot of better places that are more effective to remove weight from than the savings of a 5-speed over a 6-speed. As an extreme example of this, take the Jaguar F1 team. They run a 6-speed sequential gearbox, but use a special lightweight green paint because most green paints are too heavy.

The only time I can see the weight benefits of a 5 speed vs a 6-speed to be beneficial is in a low power car (think under 100 HP) with a flat torque curve and wide powerband, which is not exactly the prime group of cars that someone who would be considering going from a 6-speed to a 5-speed to save 20 pounds would have.

[Elfonzo]

I don't see anyone directly answering the question. If it’s a quicker ET time in a quarter mile that your after, you may wont to just swap out you're gears in the rear end. It is best to be at the top of your final climbing gear at the highest power out pot. Some cars red line is after the peek power curve and you can run slower times if you ride out your gears. I would find out were your torque curve is at before making any big decisions. A lot of newer cars with bigger engines need the extra gears to meet CAFE standards to be sold in the US, it is not always for performance.

[bandito88]

I'm trying to refurbish a 69' Camaro SS Z28. I've done some research on them and it looks like they only come in a 4-speed manual transmission. I know that there are conversion kits for 5 and 6 speed, is it worth the money to convert the 4 into a 5 or 6 speed??