TonyG > New Race Car Build Thread
#1306
Rennlist Junkie Forever
Thread Starter
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My point being that if you're only doing a very few shifts with the 5 speed then you're not losing too much time in gearchanges alone. Hopefully with the new 6 speed and ultra quick shifts you'll be able to take more advantage of the powerplant. Either way, I'm jealous!
At WSIR, using 3/4/5 gears, there are 6 gear changes. Each one costing 3/4 car length (against a no-lift 997 Cup Car). That's typically what I see when I race against them.
10.5' per shift (the car is 14' long), x 6 shifts per lap, = 63' per lap lost
63'x12 laps=756' lost per race or approx 1/8th mile back, apples-to-apples, at the end of a 12 lap race.
Even if you say 1/2 a car length per shift
7'x6 shifts per lap = 42' per lap lost
42'x12 laps = 504' lost at the end of the race to the guy with the sequential box.
Go to a track with more shifting and the difference gets worse.
That alone is why you have to go to a sequential box it if you race against people that have them.
Sucks really... they should ban them in the interest of lowering the cost of the sport... but that's never gonna happen with they come stock in factory race cars.
TonyG
#1307
Drifting
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Awesome Tony. Neat build. Congratulations!
G
G
*** Update - Car Dynoed... results in ***
Here's the dyno from today.
Note that the car is using a bone stock LS7 intake.
We're going to have a custom Wilson sheet metal intake fabricated which should be good for another 40RWHP-50RWHP. The stock LS7 intake ports just don't enough cfm to support the heads/cam.
No matter... it's making great power.
TonyG
![](http://www.tonygarcia.org/vision.951/9.1.15/TonyG.LS7.dyno.tune.stock-intake.1024.jpg)
Here's the dyno from today.
Note that the car is using a bone stock LS7 intake.
We're going to have a custom Wilson sheet metal intake fabricated which should be good for another 40RWHP-50RWHP. The stock LS7 intake ports just don't enough cfm to support the heads/cam.
No matter... it's making great power.
TonyG
![](http://www.tonygarcia.org/vision.951/9.1.15/TonyG.LS7.dyno.tune.stock-intake.1024.jpg)
#1308
Rennlist Member
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Here's some interesting math (this isn't clear cut and there are some approximations made here....)
At WSIR, using 3/4/5 gears, there are 6 gear changes. Each one costing 3/4 car length (against a no-lift 997 Cup Car). That's typically what I see when I race against them.
10.5' per shift (the car is 14' long), x 6 shifts per lap, = 63' per lap lost
63'x12 laps=756' lost per race or approx 1/8th mile back, apples-to-apples, at the end of a 12 lap race.
Even if you say 1/2 a car length per shift
7'x6 shifts per lap = 42' per lap lost
42'x12 laps = 504' lost at the end of the race to the guy with the sequential box.
Go to a track with more shifting and the difference gets worse.
That alone is why you have to go to a sequential box it if you race against people that have them.
Sucks really... they should ban them in the interest of lowering the cost of the sport... but that's never gonna happen with they come stock in factory race cars.
TonyG
At WSIR, using 3/4/5 gears, there are 6 gear changes. Each one costing 3/4 car length (against a no-lift 997 Cup Car). That's typically what I see when I race against them.
10.5' per shift (the car is 14' long), x 6 shifts per lap, = 63' per lap lost
63'x12 laps=756' lost per race or approx 1/8th mile back, apples-to-apples, at the end of a 12 lap race.
Even if you say 1/2 a car length per shift
7'x6 shifts per lap = 42' per lap lost
42'x12 laps = 504' lost at the end of the race to the guy with the sequential box.
Go to a track with more shifting and the difference gets worse.
That alone is why you have to go to a sequential box it if you race against people that have them.
Sucks really... they should ban them in the interest of lowering the cost of the sport... but that's never gonna happen with they come stock in factory race cars.
TonyG
#1309
Nordschleife Master
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The Geartronics system that controls the Albins trans has it's own computer. It doesn't tie into the GM computer. No drive by wire either. Geartronics system has it's own blipper and shift actuator.
http://www.geartronics.co.uk/paddleshift.htm
Youtube geartronics paddleshift
TonyG
http://www.geartronics.co.uk/paddleshift.htm
Youtube geartronics paddleshift
TonyG
#1310
Rennlist Junkie Forever
Thread Starter
#1311
Nordschleife Master
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I use that blipper in my Geartronics setup. It is reliable so far but I haven't got the downshifts perfectly setup yet. To get the very best rev matching the best solution would be e.g. a Motec ECU with DBW throttle integrated with the Geartronics.
#1312
Rennlist Member
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I use the motec and dbw, but these systems take a bit of tuning to get just right.
#1313
Nordschleife Master
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The flat shifts are super quick to setup but the downshifts are truly the hard part to tune in.
#1315
Rennlist Junkie Forever
Thread Starter
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TonyG
#1316
Nordschleife Master
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Here's an in-car clip:
#1318
Rennlist Member
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I hate you all....
....in the nicest possible way.
....in the nicest possible way.
#1320
Race Car
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These kind of mods are pretty much out of most people's league but it's interesting to see fully developed cars like the latest contributors on this last page of the thread.
We race PCA, so unless you are building up an all out GT car, class rules would not allow aftermarket transmissions, and while I really have no reason to investigate this avenue for SP2 and SP3 cars that we race, it made me wonder,
1) In a PCA GT car, you could probably get away with a PDK transmission as it would be "factory Porsche gearbox".
2) Following Tony's links to the pneumatic shifter setup and the transmission itself, by the time you start adding up all the necessary hardware, sorting out the software (as Duke stated)....would it not be possible (and way less expensive) to just find donor parts from salvaged Caymans and just adapt this transmission...?
I was in the transmission business for 25 years, so naturally, when the PDK arrived on the scene, I was curious enough to read as much as I could, although at the time, not much information about internals was out there (probably due to proprietary reasons) and the factory was the only way to get a unit either repaired or refreshed was through a factory exchange program.
When you hear the PCA class Caymans with PDK pass by on track, the gear change speed is unbelievable and it, by design, should be even faster than any pneumatically shifted conventional gearbox, since by design, if I understand correctly by the limited information available at the time, the next gear is already engaged before it's actually selected by the use of twin input shafts (PDK = Porsche double coupling).
T. Simon
We race PCA, so unless you are building up an all out GT car, class rules would not allow aftermarket transmissions, and while I really have no reason to investigate this avenue for SP2 and SP3 cars that we race, it made me wonder,
1) In a PCA GT car, you could probably get away with a PDK transmission as it would be "factory Porsche gearbox".
2) Following Tony's links to the pneumatic shifter setup and the transmission itself, by the time you start adding up all the necessary hardware, sorting out the software (as Duke stated)....would it not be possible (and way less expensive) to just find donor parts from salvaged Caymans and just adapt this transmission...?
I was in the transmission business for 25 years, so naturally, when the PDK arrived on the scene, I was curious enough to read as much as I could, although at the time, not much information about internals was out there (probably due to proprietary reasons) and the factory was the only way to get a unit either repaired or refreshed was through a factory exchange program.
When you hear the PCA class Caymans with PDK pass by on track, the gear change speed is unbelievable and it, by design, should be even faster than any pneumatically shifted conventional gearbox, since by design, if I understand correctly by the limited information available at the time, the next gear is already engaged before it's actually selected by the use of twin input shafts (PDK = Porsche double coupling).
T. Simon