Anyone with BIG HP do GEARS???

[jrpxxii]

I have been waiting for someone to post about gears that have high horsepower engines. I am wondering if going to 3.90 or 4.10 will actually hurt traction at the track rather than help my 60'. Is there anyone out there who has over 800hp that has changed gears? I am hoping for a guinea pig to do testing before I decide on gears.

[Robert91RS]

That will be dependent on how they make the power. If you have 800hp and 800ft/lbs right off idle than yes you will blow the street tires off the line real easy. However a vortech/procharged or NA motor will make the power more progressively. So how are you plannig to make the 800hp?

[Camarorss350]

twin turbies?

[Robert91RS]

Based on his previous posts I believe the OP has a Maggie. Several of the Maggie guys here have commented on traction issues with the stock gears so 4:10s may be too much if you don't have slicks and race axles. A properly matched stall can help to solve this problem in both cases if you don't mind the loss in mpg's. Or if you have a stick you will just need a good clutch and some practice. User name "mtcwby" may chime in later and he can give advice/feedback on a clutch and gear ratios with big HP.

[jrpxxii]

Engine will put down over 1000hp to the wheels with the nitrous and methanol. It has s/c and everything else possible and it is a 418ci. I already have all suspension pieces done and race axles and carbon shaft. I will also be running 17 Bogart drag wheels with slicks and skinnies up front. I am waiting to see if anyone that has engines like mine will benefit from gears.

[jrpxxii]

Already have clutch also.

[danhr]

If you are dead set with sticking to your current transmission, then a general good rule of thumb is this

Fit the tallest tire you can under the rear of your car, width would depend on your hp level.

Choose the gear ratio that will put you roughly 200 rpms past your redline in 4th gear. That's the part that is kind of tricky as you have to roughly know what your trap speed is going to be.

So before deciding on what gear ratio you are thinking of going with, what size tire do you plan on running and what kind of transmission are you running?

Just to throw some numbers around, say if you have a transmission with your power gear being 1:1 (most are), and you have a redline of 6300 rpms. If you run a stock height tire, and run 4.10's, you will be limited to a 131 mph trap speed, or else you will be going into over drive (if you even have over drive). Same scenario, except with 3.73's will get you 144 mph at redline in your power gear.

Honestly, unless you plan on throwing some really tall tires under your car, I would either opt for 3.73's, or staying with the factory ratio. or you will just flat out run out of gear.

[jrpxxii]

Thanks danhr that is exactly what i wanted to know.

[Hendrix-Engineering]

The more power you have the LESS gear you need,i set the six speed record in my gto with a 3.31 gear,we have an 8 second irs gto running a 3.31 gear as well.My 2 cents if you have 800 and good tq keep the stock gear.

[02 WS6 TA]

^ What he said. We have one making a touch over 1400 with 3.89s, and let me assure you, the launch is tricky at best. It's a 6 speed car, which obviously complicates things, but with enough twist, let the power do the work especially when traction limited.

[Indpowr]

I had 4.10 gears on my 600rwhp Corvette. On street tires every single gear was usless. If I had DR I am sure that it would be a lot better but 1st gear ramped up SO fast it is almost impossible to shift quick enough. I should have done 3.73..