I need gears!
04-30-2007, 11:43 AM
#1
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I need gears!
So after a 3-day weekend at Road America I have firmly decided that I need to do something about my stock 4-speed. Worn syncros aside, hitting 4th gear is like putting the damn thing in overdrive... it just slowly builds speed. As a result I probably am leaving 10-15 mph on the longer straights.
Since I have converted my car to a coilover suspension and removed the sway bars, does a G50 conversion become significantly easier (baring the clutch conversion issues)? Frankly the thought of $10+k makes my stomach turn.
The alternatives are a short R&P, which I have sitting on the shelf now, or re-gearing the existing 4 gears.
A friend has a similar 930 to mine with shorter gears and damn does it pull like a freight train straight thru forth.
Any opinions or suggestions would be greatly appreciated.
Regards,
Since I have converted my car to a coilover suspension and removed the sway bars, does a G50 conversion become significantly easier (baring the clutch conversion issues)? Frankly the thought of $10+k makes my stomach turn.
The alternatives are a short R&P, which I have sitting on the shelf now, or re-gearing the existing 4 gears.
A friend has a similar 930 to mine with shorter gears and damn does it pull like a freight train straight thru forth.
Any opinions or suggestions would be greatly appreciated.
Regards,
04-30-2007, 12:14 PM
#2
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changing the ratios will help a ton...
Everyone tells me I should be running 2:05s at VIR (my best so far is a 2:07.20), but I really don't see how I can do more without changing the gears. When I shift into 4th on the front and back straights it simply stops pulling. Its in "cruise" mode at that point.
I'd love to re-gear, just can't afford it... But I'm sure it will help your lap times....
Brian
Everyone tells me I should be running 2:05s at VIR (my best so far is a 2:07.20), but I really don't see how I can do more without changing the gears. When I shift into 4th on the front and back straights it simply stops pulling. Its in "cruise" mode at that point.
I'd love to re-gear, just can't afford it... But I'm sure it will help your lap times....
Brian
04-30-2007, 02:31 PM
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Gear Chart
Here is a gear chart I got from somewhere a while back. Maybe it will help you. My car had more torque but I found that shifting it from 3rd to 4th around 5800-6000 RPM actually produced higher speeds in the straights depending on their length, meaning that the shifting time was not a big factor.
05-01-2007, 01:41 PM
#6
930 LDR,
I went through this a couple years ago. Here are the gears I chose for my track-dedicated (but street licensed 930):
1st - 1.736 (much taller than stock, revs out at 72 mph)
2nd - 1.303 (stock, revs out at 97)
3rd - 1.000 (shorter than stock, revs out at 126)
4th - .767 (shorter than stock, revs out at 164)
I'm running 315s on the rear and using a 7000 RPM redline for comparison. It's a bit slow off the line, but comes on strong above about 30 mph. I can use first in the slowest corners and get deep into 4th on the fastest straights for our west coast tracks.
For Road America, you may want to alter these a bit, though. We don't have tracks with such long straights around here, so you may want to make 4th (and maybe 3rd) a bit taller. I raced a 911 at Road America years ago. I used to change gears to optimize just for that track. Assuming you don't want to do that, you have to compromise a bit and either have gears too long for tracks like Blackhawk Farms, or too short for RA . I'd start by asking how fast you need to (or care to) go on the main straight at RA, and go from there. I understand that a well- driven street GT3 hits about 165 tops at RA. My guess is that the 930 would do about the same. Do you know? When I was racing years ago, we saw about 150-155 in a race 911.
If you go with a tall first gear (as I have done), you get an "active" 4 speed for the track. it limits the usefulness on the street somewhat, but it allows you to use first for the slowest turns (like Turn 5). I haven't found the super-tall first gear is all that objectionable on the street, but then again, I have a high tolerance for stuff like that.
Rob
I went through this a couple years ago. Here are the gears I chose for my track-dedicated (but street licensed 930):
1st - 1.736 (much taller than stock, revs out at 72 mph)
2nd - 1.303 (stock, revs out at 97)
3rd - 1.000 (shorter than stock, revs out at 126)
4th - .767 (shorter than stock, revs out at 164)
I'm running 315s on the rear and using a 7000 RPM redline for comparison. It's a bit slow off the line, but comes on strong above about 30 mph. I can use first in the slowest corners and get deep into 4th on the fastest straights for our west coast tracks.
For Road America, you may want to alter these a bit, though. We don't have tracks with such long straights around here, so you may want to make 4th (and maybe 3rd) a bit taller. I raced a 911 at Road America years ago. I used to change gears to optimize just for that track. Assuming you don't want to do that, you have to compromise a bit and either have gears too long for tracks like Blackhawk Farms, or too short for RA . I'd start by asking how fast you need to (or care to) go on the main straight at RA, and go from there. I understand that a well- driven street GT3 hits about 165 tops at RA. My guess is that the 930 would do about the same. Do you know? When I was racing years ago, we saw about 150-155 in a race 911.
If you go with a tall first gear (as I have done), you get an "active" 4 speed for the track. it limits the usefulness on the street somewhat, but it allows you to use first for the slowest turns (like Turn 5). I haven't found the super-tall first gear is all that objectionable on the street, but then again, I have a high tolerance for stuff like that.
Rob
05-01-2007, 03:21 PM
#7
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Rob -
You bring up a good point regarding the usefulness of 1st gear. Initially I wanted to maybe shorten it a bit so that the car was more snappy from a stop on the street (I still drive it on the weekends), but having just been at road america I did find that dropping to 2nd in 5 was a little doggy too.
Funny you should mention street GT3s. I was running with a friend who just got a 997 GT3 and he was a match for a stradale at just around 160+ going into the breaking zone at turn 1. I really couldn't get up past 140 on account of the tall stock 4th gear. That is actually precisely the reason why I want to do gears now!
I think setting the box up to max out at about 160-165 would be great. I also really like the idea of setting it up to keep the stock second gear as that would keep a few bucks in the old wallet considering what I am being quoted at per gear set!
Rob
You bring up a good point regarding the usefulness of 1st gear. Initially I wanted to maybe shorten it a bit so that the car was more snappy from a stop on the street (I still drive it on the weekends), but having just been at road america I did find that dropping to 2nd in 5 was a little doggy too.
Funny you should mention street GT3s. I was running with a friend who just got a 997 GT3 and he was a match for a stradale at just around 160+ going into the breaking zone at turn 1. I really couldn't get up past 140 on account of the tall stock 4th gear. That is actually precisely the reason why I want to do gears now!
I think setting the box up to max out at about 160-165 would be great. I also really like the idea of setting it up to keep the stock second gear as that would keep a few bucks in the old wallet considering what I am being quoted at per gear set!
Rob
