915 trans rebuild options
09-15-2013, 06:13 PM
#1
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915 trans rebuild options
looks for sources on some tech advice - getting ready for my winter project
my 1981 SC track car is ready for a trans rebuild. currently have a '95 3.6 engine, mated to stock 915 with ZF lsd. car runs great but looking to get quicker acceleration out of corners. the 3.6 is pretty stock except for chip, headers and K&N which makes it pretty reliable, relatively low maint and run on hi-test gas and almost 300 hp. so what kind of gearing should i look for to take advantage of light wgt (2500 lbs) car and not sacrifice reliability. i'm told there are a great many trans gear configurations available. is there a source(s) that explains functional aspects? top speed, gear rations with speed notations, ... currently went to 17'' rims (8&9)to find decent r-compound rubber. any help appreciated. thanks in advance
Wayne
my 1981 SC track car is ready for a trans rebuild. currently have a '95 3.6 engine, mated to stock 915 with ZF lsd. car runs great but looking to get quicker acceleration out of corners. the 3.6 is pretty stock except for chip, headers and K&N which makes it pretty reliable, relatively low maint and run on hi-test gas and almost 300 hp. so what kind of gearing should i look for to take advantage of light wgt (2500 lbs) car and not sacrifice reliability. i'm told there are a great many trans gear configurations available. is there a source(s) that explains functional aspects? top speed, gear rations with speed notations, ... currently went to 17'' rims (8&9)to find decent r-compound rubber. any help appreciated. thanks in advance
Wayne
09-16-2013, 12:23 PM
#2
RL Technical Advisor
Wayne,
Two things,
1. 915's used with big engines need some modifications to be reliable and this means one-piece bearing retaining plates as well as billet side covers. 2nd & 3rd gears are still concerns unless you replace them with good aftermarket ones.
2. Gearing is all done by factoring the engine's power curves, desired top speeds, and how the car is used: street, track, competition.
Two things,
1. 915's used with big engines need some modifications to be reliable and this means one-piece bearing retaining plates as well as billet side covers. 2nd & 3rd gears are still concerns unless you replace them with good aftermarket ones.
2. Gearing is all done by factoring the engine's power curves, desired top speeds, and how the car is used: street, track, competition.
09-16-2013, 12:43 PM
#3
Rennlist Member
Wayne,
Two things,
1. 915's used with big engines need some modifications to be reliable and this means one-piece bearing retaining plates as well as billet side covers. 2nd & 3rd gears are still concerns unless you replace them with good aftermarket ones.
2. Gearing is all done by factoring the engine's power curves, desired top speeds, and how the car is used: street, track, competition.
Two things,
1. 915's used with big engines need some modifications to be reliable and this means one-piece bearing retaining plates as well as billet side covers. 2nd & 3rd gears are still concerns unless you replace them with good aftermarket ones.
2. Gearing is all done by factoring the engine's power curves, desired top speeds, and how the car is used: street, track, competition.
09-17-2013, 11:02 AM
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thanks guys. any suggestions on where to find some resources regarding these gearing options. currently the top end is about 135 in 4th (5th is overdrive and no real pull). looking to get to the top end a little quicker. this is a track only car with occasional autox. if i can get a little more top end - ok, but not willing to sacrifice acceleration for it
thanks
thanks
09-17-2013, 12:51 PM
#5
RL Technical Advisor
thanks guys. any suggestions on where to find some resources regarding these gearing options. currently the top end is about 135 in 4th (5th is overdrive and no real pull). looking to get to the top end a little quicker. this is a track only car with occasional autox. if i can get a little more top end - ok, but not willing to sacrifice acceleration for it
thanks
thanks
My advice would be to pick a vendor to source your gears through and allow them to help to select gear ratios best suited for your "mission".
09-25-2013, 02:54 PM
#6
Pro
Wayne, the side plate is not your friend especially with more thrust loads experienced in club racing.
My trans tech is Allan over at Aase Motors, Fullerton CA. He is well known in the POC , and might even have a spec. Trans in stock that can be shipped / core exchange. He once actually delivered a transaxle to a customer in his private plane, and the guy podium finished that weekend !
Aase Motors , 714.992.2283
Marty
My trans tech is Allan over at Aase Motors, Fullerton CA. He is well known in the POC , and might even have a spec. Trans in stock that can be shipped / core exchange. He once actually delivered a transaxle to a customer in his private plane, and the guy podium finished that weekend !
Aase Motors , 714.992.2283
Marty