GT4 final drive discussion
#123
I told someone the other day of our PDK analogy; "don't shift the car. Put it in auto mode. Otherwise it's like trying to talk to me when I'm having 3 open ended ADD inspired conversations with myself. Just because you're talking to it by grabbing the paddles, doesn't mean it's listening to you or paying attention."
#124
That was an awesome bike ride...
This is what it looks like inside of our sequential gearbox. A real sequential has all the fixed gears on one shaft and all the free spinning idlers on the other. When you shift, the drum rotates. All forks run on a single rod and free float on it. The drum moves them up and down. On our design, the rod is also a spray bar.
It's been designed to work with a console mounted shifter. We are currently working with someone to develop a paddle shift system that will also work with it. It will need to be in a car with MOTEC. It's going to be incompatible with a factory ECU and clearly is for a racecar only application.
We expect it to have a home much broader than just Caymans. You know the South African 917 replicas? Those cars use the original Audi turbo gearbox that became the Cayman box. How about a sequential 917 track toy? And there are any number of other mid-engine kit cars this will work well with. It is a very robust gearbox. I wouldn't hesitate to throw 600whp at it in a light 2000-2500lb racecar.
This is what it looks like inside of our sequential gearbox. A real sequential has all the fixed gears on one shaft and all the free spinning idlers on the other. When you shift, the drum rotates. All forks run on a single rod and free float on it. The drum moves them up and down. On our design, the rod is also a spray bar.
It's been designed to work with a console mounted shifter. We are currently working with someone to develop a paddle shift system that will also work with it. It will need to be in a car with MOTEC. It's going to be incompatible with a factory ECU and clearly is for a racecar only application.
We expect it to have a home much broader than just Caymans. You know the South African 917 replicas? Those cars use the original Audi turbo gearbox that became the Cayman box. How about a sequential 917 track toy? And there are any number of other mid-engine kit cars this will work well with. It is a very robust gearbox. I wouldn't hesitate to throw 600whp at it in a light 2000-2500lb racecar.
#125
Take up a collection for a group buy. Come up with a $25,000 deposit and I'll start development of 10 mainshafts. It will be 6-9 months from there with an additional $2000/unit due prior to delivery. As an official RL vendor, BGB can handle the sales and hold your money for you.
I am interested in Matt's proposal. I would prefer not to open up my transmission. I would be more eager if I could find a used tranny from a base cayman to modify. And I would like to get a better understanding of the pros and cons of doing this. From what I've already been told, these aftermarket gears are a lot noisier than the gears you can purchase directly from Porsche. For the time being, my GT4 will remain a street car that I will track occasionally. I will be less likely to modify my transmission if the car becomes less friendly to use on the street.
I suspect that interest in tranny and gearing upgrades will get a big bump once John from BGB installs the tranny he already owns (from one of his race cars) into his brand spanking new GT4. What's taking so long John??
#126
So since posting this post and after completing 4 track days I am not complaining as much about the gearing as before. However it is still obvious that there could be a benefit from a shorter final drive. Looking at available tire sizes it seems that going from 295/30/20 & 245/35/20 to 295/30/19 & 245/35/19 would result in a 3.75% reduction in final drive. So this should equate to going from the stock 3.89 final drive to 4.04. Even though the change looks miniscule I still believe that this would give much better acceleration to top speed. I would want to try this before digging into the gearbox.
#127
So since posting this post and after completing 4 track days I am not complaining as much about the gearing as before. However it is still obvious that there could be a benefit from a shorter final drive. Looking at available tire sizes it seems that going from 295/30/20 & 245/35/20 to 295/30/19 & 245/35/19 would result in a 3.75% reduction in final drive. So this should equate to going from the stock 3.89 final drive to 4.04. Even though the change looks miniscule I still believe that this would give much better acceleration to top speed. I would want to try this before digging into the gearbox.
I couldn't help wonder during the 1 time I've driven the car home, what life would be like if the 1 person who started bemoaning the gears kept quiet. I don't know if it's the fact that none of us had an idea as to how tall the GTS/S gearing was to begin with or what but i am sort of shocked at how many people talk about how bad the gearing is. I'm more baffled why everyone hates 2nd gear when i can think of almost every single race track in North America's having a true "tweener" corner where 2nd isn't tall enough and 3rd is too low in the torque curve. As the guy that sells these gears and the one that loses the most from not selling them, i think a lot of people should take a page out of this guy's book. There are power mods and RPM revisions that can be purchased to further address some of the lack of acceleration you are feeling but as much as I hear GT4 owners crying about gearing, not 1 single gear set has been sold. Race car guys buy the 3-4-5-6 because they want the 2nd gear the way it is from the factory. Back in the day when we raced Z3s and sold parts for the street, moving from a 2.9 FDR to a 4+ was a HUGE GAIN in torque but we are already at a 3.89 and there has to be a point where the laws of diminishing returns set in.
I think that the problem is that this thing really is a track car for the street with our not being able to realize the benefits on the street of the shocks, larger brakes, 2-piece arms and aero. Unless you're at maybe Willow Springs or some other big, fast track with no 2nd gear corners, i can't think of a track that wouldn't make you be happy that you have a tall 2nd gear. Sure, on the street, an 80mph 2nd gear is a PITA but is the gearing really that terrible or is the car really that good and the gears are the only thing over which to gripe??!?!?!?!?
#128
I'm more baffled why everyone hates 2nd gear when i can think of almost every single race track in North America's having a true "tweener" corner where 2nd isn't tall enough and 3rd is too low in the torque curve...
I think that the problem is that this thing really is a track car for the street with our not being able to realize the benefits on the street of the shocks, larger brakes, 2-piece arms and aero. Unless you're at maybe Willow Springs or some other big, fast track with no 2nd gear corners, i can't think of a track that wouldn't make you be happy that you have a tall 2nd gear. Sure, on the street, an 80mph 2nd gear is a PITA but is the gearing really that terrible or is the car really that good and the gears are the only thing over which to gripe??!?!?!?!?
I think that the problem is that this thing really is a track car for the street with our not being able to realize the benefits on the street of the shocks, larger brakes, 2-piece arms and aero. Unless you're at maybe Willow Springs or some other big, fast track with no 2nd gear corners, i can't think of a track that wouldn't make you be happy that you have a tall 2nd gear. Sure, on the street, an 80mph 2nd gear is a PITA but is the gearing really that terrible or is the car really that good and the gears are the only thing over which to gripe??!?!?!?!?
#129
I get the impression that this suggestion from GT Gears is dying a slow death due to a lack of interest or leadership on anyone's part. Do we need to create a separate thread to discuss this?
I am interested in Matt's proposal. I would prefer not to open up my transmission. I would be more eager if I could find a used tranny from a base cayman to modify. And I would like to get a better understanding of the pros and cons of doing this. From what I've already been told, these aftermarket gears are a lot noisier than the gears you can purchase directly from Porsche. For the time being, my GT4 will remain a street car that I will track occasionally. I will be less likely to modify my transmission if the car becomes less friendly to use on the street.
I suspect that interest in tranny and gearing upgrades will get a big bump once John from BGB installs the tranny he already owns (from one of his race cars) into his brand spanking new GT4. What's taking so long John??
I am interested in Matt's proposal. I would prefer not to open up my transmission. I would be more eager if I could find a used tranny from a base cayman to modify. And I would like to get a better understanding of the pros and cons of doing this. From what I've already been told, these aftermarket gears are a lot noisier than the gears you can purchase directly from Porsche. For the time being, my GT4 will remain a street car that I will track occasionally. I will be less likely to modify my transmission if the car becomes less friendly to use on the street.
I suspect that interest in tranny and gearing upgrades will get a big bump once John from BGB installs the tranny he already owns (from one of his race cars) into his brand spanking new GT4. What's taking so long John??
You cannot buy gears directly from Porsche, so I don't know what sort of noise comparison one can make. I manufacture parts for racecars. To make the strongest most durable gears possible, we compromise NVH needs. We relax the helix on the gear. We have a motorsport tooth profile that has a larger contact patch that loads more instantaneously than the pitter patter of a street car gear. We also reduce the tooth count to make the individual gear teeth larger and stronger. But that too makes them noisier. I can cut gears that run OEM quiet but at the expense of quality. Given that, as John said, not a single GT4 customer has gotten serious about gears yet, I'm not really motivated to invest a bunch of money in a market that only threatens to come. All the gears we've sold to date are running in 987 cars and we've gotten no complaints from anyone who has them.
My 3 gear packages (3rd-5th) still get you a much shorter stack than stock with a stock 6th for the highway. Considering that the taller of the two options will do 155mph in 5th I can't see many who will run out of gear. Even at VIR I don't think this car will exceed 155. Maybe RA or RA, definitely Daytona. But pretty much nowhere else. This option seems to satisfy most that I talk to and I've actually sold several packages of these to guys who just love them.
A 1.55 3rd versus the 1.41 stock is a huge jump. It's not 1.60 like on a 4 gear package, but it's still an immediately noticeable difference.
#130
I'm definitely still interested in a comprehensive gearing solution. I've decided it's not worth putting more street miles on the car until I can get the car the way I think it deserves to be. Maybe I'll feel differently for track purposes after a first track day in it next season but on the street you just don't get to row 'em much, which is important to me, and the acceleration feels held back.
Maybe the 19" wheels and low profile tires is somewhat of a partial solution but I think I'd rather put the $4k for wheels/tires towards the real deal.
Maybe the 19" wheels and low profile tires is somewhat of a partial solution but I think I'd rather put the $4k for wheels/tires towards the real deal.
#131
I have to admit that I do often scratch my head in bewilderment as in my Nissan racing days we used to swap out gear sets which had the 1st/2nd ratios that people are asking for and put in a gear set which had ratios around about where the GT4 is. 2nd gear that tops out at 60mph is good for 0-60 times but pretty much useless outside of that.
To me the ratios of the GT4 mean that 2nd gear is useful at the track and 1st gear is useful on the street. Everyone seems so obsessed with changing up gears that they've forgotten that you can change down. I do think that the spacing from 2-3-4-5 is a bit wide so the option to change 3-4-5 would be perfect, not only is it the cheapest option but it retains the long 6th for freeways and is best aligned with the street/track dual function of the GT4. And I suspect that the sort of people who are the type to modify gear sets understand this which is why there aren't many people lining up for the significantly more expensive 1-2 change.
To me the ratios of the GT4 mean that 2nd gear is useful at the track and 1st gear is useful on the street. Everyone seems so obsessed with changing up gears that they've forgotten that you can change down. I do think that the spacing from 2-3-4-5 is a bit wide so the option to change 3-4-5 would be perfect, not only is it the cheapest option but it retains the long 6th for freeways and is best aligned with the street/track dual function of the GT4. And I suspect that the sort of people who are the type to modify gear sets understand this which is why there aren't many people lining up for the significantly more expensive 1-2 change.
#132
I have to admit that I do often scratch my head in bewilderment as in my Nissan racing days we used to swap out gear sets which had the 1st/2nd ratios that people are asking for and put in a gear set which had ratios around about where the GT4 is. 2nd gear that tops out at 60mph is good for 0-60 times but pretty much useless outside of that.
To me the ratios of the GT4 mean that 2nd gear is useful at the track and 1st gear is useful on the street. Everyone seems so obsessed with changing up gears that they've forgotten that you can change down. I do think that the spacing from 2-3-4-5 is a bit wide so the option to change 3-4-5 would be perfect, not only is it the cheapest option but it retains the long 6th for freeways and is best aligned with the street/track dual function of the GT4. And I suspect that the sort of people who are the type to modify gear sets understand this which is why there aren't many people lining up for the significantly more expensive 1-2 change.
To me the ratios of the GT4 mean that 2nd gear is useful at the track and 1st gear is useful on the street. Everyone seems so obsessed with changing up gears that they've forgotten that you can change down. I do think that the spacing from 2-3-4-5 is a bit wide so the option to change 3-4-5 would be perfect, not only is it the cheapest option but it retains the long 6th for freeways and is best aligned with the street/track dual function of the GT4. And I suspect that the sort of people who are the type to modify gear sets understand this which is why there aren't many people lining up for the significantly more expensive 1-2 change.
#133
Likewise, for the weekend backroad driver shortening the existing gears would take 1st out of play whereas atm it's a very usable gear on the street. People seem to be very averse to changing into 1st. It's a gear, it's useful, don't be scared to use it. I've had enormous fun in the GT4 doing mountain climbs using 1-2-3 where in pervious cars I was only really using 2-3
Like I said, I think the real issue is the gaps from 2-3-4-5 and this applies both on the track and the street. And lets get serious here, if someone has bought a GT4 to push the car to limits and have fun at legal speeds on the street, well, they bought the wrong car.
#134
I think you're missing my point. The sorts of people that are willing to pony up for the big costs for 1st and 2nd aren't weekend drivers, they're typically racers. The price for changing 1st and 2nd is well above what a weekend driver will stomach.
Likewise, for the weekend backroad driver shortening the existing gears would take 1st out of play whereas atm it's a very usable gear on the street. People seem to be very averse to changing into 1st. It's a gear, it's useful, don't be scared to use it. I've had enormous fun in the GT4 doing mountain climbs using 1-2-3 where in pervious cars I was only really using 2-3
Like I said, I think the real issue is the gaps from 2-3-4-5 and this applies both on the track and the street. And lets get serious here, if someone has bought a GT4 to push the car to limits and have fun at legal speeds on the street, well, they bought the wrong car.
Likewise, for the weekend backroad driver shortening the existing gears would take 1st out of play whereas atm it's a very usable gear on the street. People seem to be very averse to changing into 1st. It's a gear, it's useful, don't be scared to use it. I've had enormous fun in the GT4 doing mountain climbs using 1-2-3 where in pervious cars I was only really using 2-3
Like I said, I think the real issue is the gaps from 2-3-4-5 and this applies both on the track and the street. And lets get serious here, if someone has bought a GT4 to push the car to limits and have fun at legal speeds on the street, well, they bought the wrong car.
I bought the car for fun daily driving at legal speed on the streets AND occasional track use... and I am sure 70-80% of the people bought the GT4 for that same reason. You are making it sound it like its one way or the other...why cant we do both?
You would be surprised, once the warranty runs out, what kind of people will pony up for some gear box fix. Just saying.
#135
I plan on throwing a nice chunk of money at this or I'll sell the car. Just isn't fun on the street for me (I only have time for about 3-4 track days per year). My E46 M3 is geared perfectly for the street. I can't believe I'm having 7x the fun for 1/7th of the price. I think the GT4 would be so much better on the street with tighter gearing (of which 2nd gear is essential).
Last edited by Accel Junky; 11-10-2015 at 06:52 AM.