Anyone run a GV Over/Under drive on an 11 second street/strip car?

Just wondering if it would improve e.t.'s any as stated on the Gear Vendors web site.


Thanks,

Chris

Chris,
I ran a GV in my high 11 second Camaro. I didn't play around enough to figure out what/if anything wold make a bug difference. the only things I tried was going 1st, 2nd, 2nd OD, 3rd.I was wondering if going 1st, 2nd, 3rd, 3rd OD would work better. I have a GV in my current project it should go a bit quicker than 11's, I'll take my time testing to see what works best.

One thing you have to remember is rear gear ratio will be a big part in determining what works best.

If you plan to drive your car on the street I highly recommend the GV, if it is a race only car, I don't think I would bother.

I'm using one behind a TH-400 for my project. Street/strip 79 Camaro, 540 ci with a Procharger and EFI. I want to use it for racing so I don't have to turn the motor up so hard on the big end, I'm hoping I can plant the tires with a 3.89 gear and pop it in OD for a huge top end charge.

Then I can use it to putt around on the street and not have to be buzzing up the motor while running down the highway.

Rob

I'm using one behind a TH-400 for my project. Street/strip 79 Camaro, 540 ci with a Procharger and EFI. I want to use it for racing so I don't have to turn the motor up so hard on the big end, I'm hoping I can plant the tires with a 3.89 gear and pop it in OD for a huge top end charge.

Then I can use it to putt around on the street and not have to be buzzing up the motor while running down the highway.

Rob How big a Procharger do you have? There are several running here now on small blocks and all of them are using 3.50 gears and the main problem is traction. One Ford with an F2 has already run 8.00 @ 179 MPH and doesn't hardly have any gear in it. It is probably going to turn that gear vendors OD into a $2400 pile of scrap metal.

It is probably going to turn that gear vendors OD into a $2400 pile of scrap metal.

oh no, it will not...

Harold, I hope I don't gernade the GV, they do rate it for 1200 HP, maybe I should stick to 1/8 mile racing and forget the big MPH. It would keep my drawer's cleaner anyways, LOL.

What size Procharger? I'm running the F2 :D

On second thought,,,,,I'll probably soil my drawers anyways :) hehehe

Rob

oh no, it will not...


I would think that because the rpm drop is half of what it would be without the g/v that it be easier on drivetrain parts...

Yes, the GV in stock form is rated for 1200HP and can be modified if needed to handle much more. They are VERY strong units. I've been running mine for years with no issues.

bowtie,
It is a 70% OD not 50%. I don't think it will be any harder on parts. If you launch in 1st hit OD and then shift from there it will actualy have less RPM drop than going 1st, 2nd, 3rd. You can also split gears which will also reduce RPM drop.

Many people don't understand how they work, it is real simple. Basically a 2 speed tranny, that you can shift into and out of at any RPM or speed (or in any gear).

As far as gear ratio, 3.89's will work fine. You don't need a bunch on gear with a blower. I went with 4.11's and even with them I can cruise 80MPH on the freeway and not buzz the engine to much. I will build a center section with 3.50's soon, just to see if there is much difference.

Some mag recently had a great article on the GV unit. They explained it very well. They have an option that will allow it to shift much faster into OD/UD for drag racing but it kind of sounded like it was not perfected yet. It does take a moment or so when it shifts, but around town when I'm deep in the throttle and I forget its on and at 45-50 it kicks on its hard to notice much except the drop in rpms and the jump in tire spin or acceleration.

I love mine except my car's electrical issues disrupt it now and then.

THey can build them for up to 2000HP I believe. They are pretty beefy.

according to them it takes ".8" seconds to shift....I can tell there is delay but not bid deal really...

you get 6 gears out of a TH400...1st- 1stOD-2nd-2ndOD-3rd-3rdOD....

Harold, I hope I don't gernade the GV, they do rate it for 1200 HP, maybe I should stick to 1/8 mile racing and forget the big MPH. It would keep my drawer's cleaner anyways, LOL.

What size Procharger? I'm running the F2 :D

On second thought,,,,,I'll probably soil my drawers anyways :) hehehe

Rob That F2 powered 540 big block is capable of making way more than 1200 H.P. The 406 Camaro here has run 8.41 @ 164 MPH with 3.50 gears. The Ford has been dynoed at 1700 H.P. and it too is a small block with an F2. Mark Micke's 526 BB with an F3RR has made 2700 H.P. While the gear vendors OD may not be the weakest link in your driveline the combination you have will certainly exceed it's 1200 H.P. rating by a bunch. My son's 598 has just finished breaking it's fourth or fifth 400 Turbo, one which had a 1500 ft.lb. rated sprag and a billet aluminum drum, it lasted three runs and succumbed to the first nitrous hit. You'd be wise to run your present driveline by the people a ATI and see what they think. I hope you have a real good driveshaft with the biggest and strongest "U" joints you can find as i suspect that will break first. What kind of rear end and axles do you have?

I hear ya Harold, I don't plan on pushing the GV too far past the 1200 rating,,,,maybe by just a couple hundred :D. In all actuality, I probably won't run 1/4 mile, we mostly do 1/8 mile in these parts. I'll mainly use the GV when running around town. I've got a bud itching real bad wanting to build me a Glide which is what I should have went with when I started all this madness. At any rate we're going to stick it out with the TH-400 and GV unit and hope my luck runs a little better than what you and your son have been through. BTW, my trans is a JW unit rated for "1500 HP",,,,,,sound familiar, LOL. I hope it can hang, it'll hurt my feelings if I grenade it.

The rear end is the trusty 9", with all the race doo-dads, it even has chromoly tubes and ladder bar brackets, I'm building up an alumn chunk with Moser 35 spline guts.

Let me ask you a question, with that big nitrous motor did you launch off the trans brake or foot brake it? And did you run the stock first gear or did you run the 2:10 first gear?

I'm running the stock 2:48 gear, I have a feeling I'm going to be in for a major shock (no pun intended) the first time I let go of the trans brake.

Rob

I hear ya Harold, I don't plan on pushing the GV too far past the 1200 rating,,,,maybe by just a couple hundred :D. In all actuality, I probably won't run 1/4 mile, we mostly do 1/8 mile in these parts. I'll mainly use the GV when running around town. I've got a bud itching real bad wanting to build me a Glide which is what I should have went with when I started all this madness. At any rate we're going to stick it out with the TH-400 and GV unit and hope my luck runs a little better than what you and your son have been through. BTW, my trans is a JW unit rated for "1500 HP",,,,,,sound familiar, LOL. I hope it can hang, it'll hurt my feelings if I grenade it.

The rear end is the trusty 9", with all the race doo-dads, it even has chromoly tubes and ladder bar brackets, I'm building up an alumn chunk with Moser 35 spline guts.

Let me ask you a question, with that big nitrous motor did you launch off the trans brake or foot brake it? And did you run the stock first gear or did you run the 2:10 first gear?

I'm running the stock 2:48 gear, I have a feeling I'm going to be in for a major shock (no pun intended) the first time I let go of the trans brake.

Rob Hi 66, Here is the good and bad news both. The transmissions have not exploded they do however roll the 2 gear sprag. The good one that just broke was the one that had the 1500 ft.lb. rated sprag along with the 2.10 first gear option and the billet aluminum drum that is supposed to prevent this problem. It went through it just like the rest. I'm pretty sure that a real good glide is the only option left. A good transmission guy has put in a couple of new tricks back in the good trans. and my son is going to try it in a couple of weeks. My son always foot brakes his car and all this damage has been done leaving at about 3000 RPM so there is no easy way out that i know of. We were using a 540 and it didn't hurt any transmissions but this bigger motor is a bear. The 9" Ford rear end has been fine but we broke one driveshaft. Do not transbrake your 2.48 gear as traction will be your #1 problem unless you get a top of the line 'glide with the 1.80 straight cut gear set and all the best internals. Contact "Hutch", Keith Neal or a real good shootout transmission builder. If i were you i'd replace the aluminum center section with a Nodular iron one as the aluminum housing distorts with big power and probably won't hold up. The only exception to this is the Strange Ultracase perhaps, but the Nodular iron case is stronger. The 3.89 gear is way to low for a gear as your motor will probably make 1500 H.P. without breaking a sweat. Get yourself at least a 3.70 or better yet a 3.50 gear. A real bias ply slick is better than a radial as my son said his was chattering the tires with the radials and that breaks axles and driveline parts. The radials either spin or try to stand way up or both. A Kansas City who comes down to our shootouts has a '68 Camaro convertible with a 540 and F2 Procharger, powerglide trans., 3.50 gear on alcohol which ran 7.94 @ 179 MPH earlier this year and weighes about 3550 lbs. so you should have plenty of power. It will definately surprise you if you haven't ever had a very high horsepower car before. Good luck.