gear ratios

[The Radium King]

so, if one were to put a larger motor in their car (i.e., more torque, hp) what would be a better transmission for the track - the 5 or 6 speed? apparently the 6 speed can handle a bit more power, and has closer gearing so that rpms don't drop as much between shifts. the 5 speed ratios are not as tight so that you'll have more rpm drop on shifts but the torquier engine should be able to mange it. further, with longer legs in each gear you wouldn't be rowing as much, which might be a benefit on a more technical track?

[JFP in PA]

Five speed.

[The Radium King]

and, five speed is lighter and has better axle orientation than the 6 speed ...

[BYprodriver]

I wonder if anyone has done a chassis dyno comparison with 5speed & 6speed ?

[JFP in PA]

Originally Posted by BYprodriver

I wonder if anyone has done a chassis dyno comparison with 5speed & 6speed ?

I doubt that running a comparison on a chassis dyno would show anything useful. Problem is the dyno is measuring torque and imputing HP at any given RPM, neither of which would change as the engine is the same, they would just shift in relation to the wheel speeds. Plus most chassis dyno's don't like gear shifts under power as the car tends to start moving about.

One of the single biggest advantages of the five speed is the difference in weight Radium noted, which is considerable (to the tune of about 100 lb. all in), and the dyno has no idea how much the car weighs.

[Bigsmoothlee]

I have a 3.4, and I will be installing an early 5 speed transmission in my car.

The final drive is 3.89:1, so acceleration would greatly improve. Ive always felt that the later 5 speed and 6 speed had gears that were a bit too long...

[jaykay]

Doesn't the 6-speed transmission have a higher power transmission capacity?

During my limited track time, I have never used six.....perhaps due the large elevation change on the one long straight I have encountered

[Topless]

With a 3.4L I would add a motorsport LSD and trans cooler to preserve reliability. Wheel spin kills em quick.

[BYprodriver]

Originally Posted by JFP in PA

I doubt that running a comparison on a chassis dyno would show anything useful. Problem is the dyno is measuring torque and imputing HP at any given RPM, neither of which would change as the engine is the same, they would just shift in relation to the wheel speeds. Plus most chassis dyno's don't like gear shifts under power as the car tends to start moving about.

One of the single biggest advantages of the five speed is the difference in weight Radium noted, which is considerable (to the tune of about 100 lb. all in), and the dyno has no idea how much the car weighs.

I realize that. I was thinking about axle angularity effect on driveline loss?

[Jittsl]

What is the intended use of the car? I wouldn't rush to put a cooler on a street car unless you drive like a complete a..hole. Cooler only comes into its own under extreme heat, constant high speed and beating on the car.

In answer to how spec racers are set up- mine is exactly as you described other than I have a non-return valve to stop pumps etc. from draining back overfilling the tranny when not turned on. I bought the required parts on eBay and through Summit and spent about $500 on the whole set up. Kit probably not needed.

[The Radium King]

street/track use. 3rd gear gets very vague when things heat up at the track; hoping a trans cooler would fix it. that's why i don't want to get too fancy with a temp sensor triggering the pump or anything; just turn it on at the track and off on the street. also don't want to be drilling the case; if i can fix the issue just by repurposing the drain and fill openings then i am happy. given my intended use a check valve seems a good idea; thanks.