shorter 1st gear to improve low end torque?
05-26-2018, 02:45 AM
#1
Three Wheelin'
Thread Starter
shorter 1st gear to improve low end torque?
Anybody have any info on how much modification to shorten first gear? Seems our cars has a tall first gear which exacerbates the low compression engine off the line. Just wondering if anyone has heard of anybody doing this......kinda makes sense if you want lower end engagement for running around town.
05-26-2018, 04:58 AM
#2
Get a S2 box, everything is shorter, and unless you’re chasing top speed beyond 150mph you won’t miss the tallness of the stock box. I love mine, wakes everything up.
Throw in a only944 short shifter linkage and shifter and you’re off to the races.
Throw in a only944 short shifter linkage and shifter and you’re off to the races.
05-26-2018, 11:11 AM
#3
Rainman
Rennlist Member
Rennlist Member
951 has a 3.5 1st gear but a 3.375 axle ratio.
S2 has 3.5 1st gear but a 3.875 axle.
so you could swap an S2 box for easier 1st gear takeoffs but it would affect all your gears' max MPH, not a huge amount but youll be shifting more often.
S2 has 3.5 1st gear but a 3.875 axle.
so you could swap an S2 box for easier 1st gear takeoffs but it would affect all your gears' max MPH, not a huge amount but youll be shifting more often.
05-26-2018, 12:12 PM
#5
Rennlist Member
Fist gear is too tall for you? Interesting, in my car (higher power), first gear is too short really. If it hooks up and doesn't just spin the tires, I still have to work hard to get it off the rev-limiter. Second gear is my favorite with traction, and the upper gears could all be lower in my book, at least for a street car. Consider adding power. 
05-26-2018, 12:50 PM
#6
Three Wheelin'
Thread Starter
Yeah, I'm getting ahead of myself. I do need to make a decision about which engine management/chip combo to use. My car is internally stock, just did the K27/6 mod (with clipped hot side), old LR MAF (stock Porsche chips), LR 3 inch exhaust. I'm trying to make up my mind between Vitesse and VEMS. You guys have any insight? Which would you do if you had to do it again? You can PM me if you wish
thank you!
thank you!
05-26-2018, 01:02 PM
#7
Professional Hoon
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Fist gear is too tall for you? Interesting, in my car (higher power), first gear is too short really. If it hooks up and doesn't just spin the tires, I still have to work hard to get it off the rev-limiter. Second gear is my favorite with traction, and the upper gears could all be lower in my book, at least for a street car. Consider adding power.
Yeah, I'm getting ahead of myself. I do need to make a decision about which engine management/chip combo to use. My car is internally stock, just did the K27/6 mod (with clipped hot side), old LR MAF (stock Porsche chips), LR 3 inch exhaust. I'm trying to make up my mind between Vitesse and VEMS. You guys have any insight? Which would you do if you had to do it again? You can PM me if you wish
thank you!
thank you!
My weekender 944t has a M-Tune (Lindsey Racing supply it now) But my track car im building will be powered by a motec. They all have their place.
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05-26-2018, 01:46 PM
#8
Rainman
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Tom, OP sounds like he's concerned with "normal driving" stoplight takeoff power rather than Saturn V launch control.
low CR plus tall gears can make takeoff hard especially on a hill...have you ever driven uphill on Laguna St. in SF with traffic? if you stall, you're rolling backwards into the ocean, LOL
ttAmerica - one pleasant result from a MAF or MAP (VEMS) conversion is a LOT more off-idle and low-end torque, without the AFM choking off the intake tract, boost or not.
years ago i did lots of dyno testing on my NA, and swapping the AFM for a MAF and some minor tuning made over 10% more torque down low where it counts.
low CR plus tall gears can make takeoff hard especially on a hill...have you ever driven uphill on Laguna St. in SF with traffic? if you stall, you're rolling backwards into the ocean, LOL
ttAmerica - one pleasant result from a MAF or MAP (VEMS) conversion is a LOT more off-idle and low-end torque, without the AFM choking off the intake tract, boost or not.
years ago i did lots of dyno testing on my NA, and swapping the AFM for a MAF and some minor tuning made over 10% more torque down low where it counts.
05-26-2018, 06:07 PM
#9
Rennlist Member
By the way, I was lucky enough to drive an RS America a while back and can confirm the 951 will never feel like that no matter the gears.
05-27-2018, 12:10 AM
#10
Three Wheelin'
Thread Starter
Thanks guys. Yeah, i'm looking to get this car sorted out. I gave it to my son who is now 22 years old. I owned it first when I was in my thirties while a resident at USC medical center in LA. Means a lot to me that he's head over heels for it, but he's still learning to drive stick, hence, my wanting to get the off idle torque improvement.
Tom I bet that RS America was sweet! My dream-car has alway been the 911 wide body 930 turbo look. I was somewhat lucky to purchase my 911 America Roadster from a Seattle Mariners baseball player who had made the stock drive train conversion to a 993tt running gear. I added the RUF conversion a year later. Very fun car to drive except I get a lot of traffic tickets.
The 951 needs a lot of TLC and upgrades $$$ but these cars are staying in the family!
Tom I bet that RS America was sweet! My dream-car has alway been the 911 wide body 930 turbo look. I was somewhat lucky to purchase my 911 America Roadster from a Seattle Mariners baseball player who had made the stock drive train conversion to a 993tt running gear. I added the RUF conversion a year later. Very fun car to drive except I get a lot of traffic tickets.
The 951 needs a lot of TLC and upgrades $$$ but these cars are staying in the family!
05-27-2018, 01:53 PM
#11
I’d talk to raceboy and go VEMS, lots of benefits including built in scopes for sensors, MAP fueling and EBC. Plus you can change everything on your laptop and auto tune, and any future mod can be accounted for in the management over Bluetooth. I’ve enjoyed it, and not having to deal with old DME stuff.
05-28-2018, 11:53 AM
#15