What rear-end ratio to use?

John's 1995 Venom 550 · Apr 27, 2001

I just installed an aluminium flywheel and clutch which changed the way the car responds. I have lost some of the "pushing you into the back of the seat" feeling felt on launch. Some have recommended changing the stock rear-end ratio to get that feeling back. Has anyone done this before, what gear, and could they give me their opinion? Please let me know the pro's and con's of such a change, and the possible cost?

Thanks again,

John

GaryA · Apr 27, 2001

I don't have the aluminum flywheel, but I did change the gear ratio on the rear end to 3.55 with good (SOTP) results. Basically, by changing the gear ratio from the stock 3.07 to 3.55 I lose top speed, but I gain low end thrust. This topic has been discussed here before and someone posted a link to a site that explains this very well.

Here's the link:

http://www.socalviper.org/techtips/gears.html

Venom Lover · Apr 27, 2001

I don't know how much the article in Gary's link goes into this, but....

If you're looking for good SOTP feel driving around, go with a 3.55 gear, or maybe even a 3.73.

If you're looking for reduced ET's drag racing, do not exceed a 3.55 numerical ratio, or you'll have to shift to 5th before the traps. In fact, depending on how high you dyno, you might want to consider a 3.45 gear for drag racing.

If you're looking for best lap times road racing, stay with the 3.07 gear. The extra shifting you'll probably have to do on most tracks with anything higher (numerically) will probably cost you time.

I decreased my 60' times and ETs a solid tenth on street tires and slicks with the 3.55 rear end.

Marv S · Apr 27, 2001

http://www.socalviper.org/techtips/TT10.HTM

and
http://www.socalviper.org/techtips/gears.html

SoCal Rebell · Apr 27, 2001

I have an aluminum flywheel and 3.54 gears, I love them, SOTP feel is great and I'm getting great 60 ft. times at the track, steady 1.81/1.82.

Tom Welch · Apr 27, 2001

Johns venom,

I suggest with the power that you make, stay with the 3.07 gear. Call HMS and ask them what gear is in their hot rod cars, John will tell you 3.07.

With over 700 hp on tap I couldn't imagine shifting any faster than I do now with my 3.07 gear.....not to mention having to shift into overdrive to complete a 1/4 mile pass with a higher than stock numerical gear.(also the 2-3 shift is hard enough to make once in a 1/4 mile pass, with a gear change and nitrous count on having to make it twice..4-5)

If you didn't have nitrous the 3.45(54) gear would be decent for street use but be advised that higher numerical gears means breaking the tires loose easier, which in turn slows elapsed times.

Tom

John D · Apr 28, 2001

From Jon B:
"When we sell aluminum flywheels, we WARN you that you will lose 0-30 mph speed, but increase 20-120mph acceleration. We also suggest a 3.55 to re-gain this. A great choice."

Why is it that with the aluminum flywheels that your 0-30 will suffer? If the engine can spin quicker, why would you end up slower off the line?

What rear-end ratio to use?

John's 1995 Venom 550

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GaryA

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Venom Lover

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Marv S

Former VCA National President

SoCal Rebell

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Tom Welch

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John D

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