Traction and gears

[AKcharger]

I was planing on replacing my 3:23 SG for a 3:91 SG when my 470 stroker goes in this winter...but I was thinking about traction? A lot of people complain about spinning the tires with steep gears.

So question is with stock tires will I really get my money's worth out of a 3:91 gear or will 3:23's make better use of the torque?

Thanks!

AK

[aifilaw]

 
steeper gears will actually mean you get less wheel-spin.

The question of whether or not you will be using the torque from that stroker buildup to its best ability is another factor altogether that is of a much higher consideration. 3.91's is not a tremendous step, but there's a few other factors to be considered.
Is this a track only car? What percentage of its use will be seen on the street? What transmission? Overdrive? weight of vehicle, and what kind of tires do you plan on putting on it for the duality or singality of uses?

Generally speaking, for a car that will see the track maybe 4 or 5 times a year, and mostly street driven, with no overdrive unit and a stroker of that size, sticking with the 3.23's, putting in a pinion snubber, some LCA's, a smart drive with the throttle, and decent tires and you will be money and time (ET) ahead of putting in 3.91's.

[Nacho-RT74]

maybe an intermediate point ? 3:55 ? ( just in case I have it NOS hehehe... 741 and 489 )

[AKcharger]

Well It might see the strip 4 times in a year if I really strech my imagination mostly weekend crusing car
- Stock Auto
- 3900 lbs
- not sure on tires...yet

[aifilaw]

weekend cruiser is a big difference from something you'd take on a road trip... or try to pull the max ET out of. So tire wear is a factor and getting some decent cheapo tires that aren't going to break loose will be assisted by a taller gear. I'd switch to the 3.91's if I was in your shoes, more fun on the streets and the gearing will help in the short burts of speed and getting their quick (basically making a 1/8 mile car out of it) because you aren't going to want to do the 100+ thing on the streets.

[firefighter3931]

  The 3.91's are an excellent choice. With a 28in tire the final drive ratio works out to 3.6 so it' easy to live with.



Ron

[AKcharger]

Roger that !

Thanks

[John_Kunkel]

  With a 28in tire the final drive ratio works out to 3.6

Sorry, Ron, but I always choke when I see a statement like that. Regardless of tire size the "final drive ratio" is still 3.91.

Has someone set a standard that a 25.5" tire is "stock".

[firefighter3931]

  With a 28in tire the final drive ratio works out to 3.6

Sorry, Ron, but I always choke when I see a statement like that. Regardless of tire size the "final drive ratio" is still 3.91.

Has someone set a standard that a 25.5" tire is "stock".

Right you are John.....technicly the gear ratio stays the same but the car's effective gear ratio is reduced due to the taller tire.



Ron

[oldster_1]

I don't know about anyone else, but whenever I myself have built even a 'street' cruiser or 'street/strip' car, I still go with a gear that matches the combo, i.e. motor, weight of car, trans, etc etc. But, in my case, my cruisers or street strip cars have never been used to 'cruise' 50+ miles over highways either. With cars like this I could care less about gas mileage or the rpm the engine's turning at such and such mph. I want the car to run at it's optimum performance wise whether it's for the track only or double duty. Car's for fun in my eyes, not for driving to a vacation destination.

[Chryco Psycho]

I generally use enough gear to keep the engine in its powerband for the intended use so if you are planning to do a lot of highway make sure the engine is into the powerband @ the speed you want to go

[Challenger340]

I Vote the 3.91 and tall tire(28") idea,
best of both worlds,
although,
I tend to live in another world sometimes, and I like to be "ready to play".

Bob out.

[68RT4ME]

 I'm running 3:91's with 275/60-15's. They are 28 inches tall but, I'm also using a GearVender's Overdrive unit on my 727. I can run the highway at 80mph @ 3100 rpm's. 85 mph @ 3500. I can set it to auto and it jumps on at around 45 mph or I can switch it on manually in any gear effectively making my 3 speed auto, a 6 speed auto.

With the 3:91's, I get the best of both worlds. A good street/strip gear and great highway cruising to boot. The mielage is good too considering how heavy these things are and the speeds I go.