Thread: 57 Chevy Cruizer

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Originally Posted by jerry clayton

The big thing to remember about planetary gear o-d are that it freewheels on decel and that might not be what you want in a road racing enviroment------not only does it freewheel in those od gears, but that F's up your braking effort as in order to get enough rear brakes for in od, you will have lock up tendancy of the rears when in any hard gear----------

Sooooooooooooo------------------not only do u have to remember the order of gears going up and down, you have to remember the braking scenario---------and most time gains on a road course are from the braking/turn in areas of the curves, not the exits to the straights

Very true, Jerry. Corner entry has to be done in a straight gear and not overdrive. We played with one of these many years back on a road course, you only enter a corner once in OD and it goes right to the top of your "things not to do" list!!! So, corner entry speeds and braking become the same as any non-od car... From just prior to the apex and out, the closer split on the ratio with the od gear being selected, ie 3rd to 3rd od accelerates the car quicker. Getting out of the turn harder will get you to the next turn sooner!!!!

Same thing in a drag car with a glide and a Gear Vendors. Set one up for a friend a number of years back, instantly took time off his 60', was able to get deeper in the rear gears and therefore a harder launch and with the od on drive still maintained the same rpm on the top end....

Originally Posted by Dave Severson

Very true, Jerry. Corner entry has to be done in a straight gear and not overdrive. We played with one of these many years back on a road course, you only enter a corner once in OD and it goes right to the top of your "things not to do" list!!! So, corner entry speeds and braking become the same as any non-od car... From just prior to the apex and out, the closer split on the ratio with the od gear being selected, ie 3rd to 3rd od accelerates the car quicker. Getting out of the turn harder will get you to the next turn sooner!!!!

I think I'd have to run a parallel circuit on that OD pushbutton to light an indicator lamp in a prominent place on my dash when that Gearvendors unit was engaged! I can just see myself exiting a corner tangent to the apex, with an "Oh yeah, I was in OD coming in...."

Dave, I know you've thought this thing through with some one-on-one bench racing sessions on the side and the decision is pretty much made at this point. I want to thank you for educating me on the Gearvendors unit. I had overlooked articles on them, like the one from David Freiburger singing their praises in Hot Rod (on Gearvendors web site). I'm thinking that I could have a blast with one of those and a traditional 4-speed in a cruising machine. I dearly love running the gears, and the unit's strong! I'll look forward to more insights into the powertrain you're building! Thanks!!

Originally Posted by rspears

I think I'd have to run a parallel circuit on that OD pushbutton to light an indicator lamp in a prominent place on my dash when that Gearvendors unit was engaged! I can just see myself exiting a corner tangent to the apex, with an "Oh yeah, I was in OD coming in...."

Dave, I know you've thought this thing through with some one-on-one bench racing sessions on the side and the decision is pretty much made at this point. I want to thank you for educating me on the Gearvendors unit. I had overlooked articles on them, like the one from David Freiburger singing their praises in Hot Rod (on Gearvendors web site). I'm thinking that I could have a blast with one of those and a traditional 4-speed in a cruising machine. I dearly love running the gears, and the unit's strong! I'll look forward to more insights into the powertrain you're building! Thanks!!

Already addressed it Roger, thinking it will be a light mounted off the base of the shift light....always seem to be looking at it when things are getting serious..... I was involved with a couple cars running these behind powerglides, and was amazed at the improvement in 60' times!!! If they do that much for a 2 speed, why not run them with a five speed???? I know the shift time on the od is faster then I can pull the handle for a regular gear change, too. Also, I was doing some suspension tuning on a customer's "open track" type Mustang many years back, he had one behind a Liberty modified T-10 4 speed, that shift to od out of a corner would keep the engine in it's peak torque and accelerate the car harder, I would imagine most of that is from the decreased loss of rpm between gear changes when going from a trans gear to the 22% increase in ratio of the od gear....