kary993

I had been thinking about this since a number of us Rennlister's did the California Speedway event in March. There were three of us with 993's. All three had a light weight flywheel and clutch package, but two of us had the G50/20 (US) and one had a modified G50/21 tranny.

Here is the deal. We entered the speedway oval together in a row. The entrance is long and the three of us were basically traveling together. Down the front straight we would get to around 135 mph before going into turn 1. The thing that we saw was the G50/21 car never pulled away. The cars stayed even all the way. As we entered turn 1 then differences occurred but only because of tires and different suspensions.

So my question is why would the G50/21 car not pull quicker down the straight?

BTW, the G50/21 did very well on the infield in some tighter turns as compared to the G50/20. The G50/21 also had a Porsche Motorsport limited slip so that helped greatly in the tighter corners.

DJF1

That is odd Kary. I saw a difference of as much as 10mph on the long straight at TWS. Could have been only that coming out of the last corner with the shorter 3rd my car was full on the powerband and therefore I had greater acceleration off the corner? Still I feel that I for sure pull more on the straights as the shorter box never leaves the engine off the power band like the 20 does.

Greg Fishman

Too much variance in drivers to make a valid comparision. Was he shifting at redline, was his exit speed the same? At Daytona I would out pull a friend with a US gearbox we would be neck and neck until we hit 5th and 6th gears.

Greg Fishman

Kary,
Were all three of you on the same diameter tires? That can also effect the effective gear ratio.

kary993

Greg, we all were shifting at around 6600 to 6700 justunder redline as we do not feel there is reall all that much found up at 6800 other than the rev limiter.
We were entering the straight at the same speeds as the distances were maintained to the entire tiem from the entry to the end of the straight. You do bring up a good point though about diamters. My P-Zero slick diameter all the way around is 25.39. Theother was 18" wheels with 285/30/18 I believe and the other were 17" with 275/40/17, I think? I would need to clarify that which is easy to do.

So that would mean that the diameters were:
25.39 - 285/645/18 (Mine G50/20)
25.66 - 275/40/17 (G50/21 tranny)
24.74 - 285/30/18 (G50/20)

My car has the club sport wing (drag) and splitter and the other two have the RS wing and splitters.

Glen

Hmmm Danny, 10 mph hmmmmboy I wonder how You could get 10mph , hmmm just cant figure that out...ROFL

DJF1

That was BEFORE!! Now...
Next time we meet you got to drive it..