Max torque for a Jag Getrag box

[kayjayd]

Any of you knowledgeable sorts got any views on the maximum torque a Jag Getrag box would cope with before it gives up? I know the AK demo motor is a decent SBC with a blower so that's got have a few ft/lbs pushing through it's getrag.

I'm seriously thinking about a motor with about 460 ft/lbs. Am I being daft to hope the getrag will cope? I could do without adding a Tremec to my spreadsheet at the moment

[CycleSi]

Don't worry about a Getrag box coping with that sort of torque - it will !!!

My AK has a 409ci SBC in it making over 500 lbft torque and it has lasted 9 1/2years although I did have to get it rebuilt recently when I "over did" it racing a Skyline.

The Getrag is supposed to be a nicer shift compared to a Tremec anyway?

[kayjayd]

Originally Posted by BEB

Don't worry about a Getrag box coping with that sort of torque - it will !!!

My AK has a 409ci SBC in it making over 500 lbft torque and it has lasted 9 1/2years although I did have to get it rebuilt recently when I "over did" it racing a Skyline.

The Getrag is supposed to be a nicer shift compared to a Tremec anyway?

Thanks for that - Right then, where's my credit card?

[RobinH]

These boxes are renowned for being pretty well bullet proof; however, like anything mechanical, any particular unit may not be as fit as the fittest around. It may not have had oil changes early in its life, if may have been over-pushed at some point and it may of course just be of a Friday afternoon manufacture, after the guys had come back from the Dom Kolsh house! All of course hard to tell without a detailed examination by an expert, so why not just give it a go and rebuild or replace if you are unfortunate and it goes pop!

[kayjayd]

Originally Posted by RobinH

These boxes are renowned for being pretty well bullet proof; however, like anything mechanical, any particular unit may not be as fit as the fittest around. It may not have had oil changes early in its life, if may have been over-pushed at some point and it may of course just be of a Friday afternoon manufacture, after the guys had come back from the Dom Kolsh house! All of course hard to tell without a detailed examination by an expert, so why not just give it a go and rebuild or replace if you are unfortunate and it goes pop!

Sound logic Robin. I'm only paid £150 for it so if it does let go then it'll be no big deal to replace it or maybe upgrade later.

[mikey]

The Getrag box comes nowhere near coping with that sort of power if used in any serious way. If you are using a set of Toyos or similar with an AA traction rating and you decide to use the power in 4th particularly on a slight incline you will destroy the first motion shaft, this is the weak component.

The Toyota Litace box (not the Supra Turbo) is slightly stronger at the first motion shaft mainly due to tighter Toyota tolerances, but even that comes nowhere near. I destroyed two Getrag and one Toyota gearbox before I had enough and purchased a Tremec which ended my worries. Until that point, I was always nervous about using the acceleration. The cost of the three gearboxes and the 2nd conversion kit meant I could have bought the Tremec in the first place.

In those motors where they are surviving, the torque will be being produced at a much later stage, so its more likely that the strain will not be as high. In the 409 it will come low down and as you should be making your shifts earlier to benefit from the cubes and gearing it will be taking significantly more stick.

If you can budget for it, go for the Tremec, otherwise you will always be gambling with potential failure. Looking at the cost of a decent 409 set up do you not think it is worth the extra.

Thats my advice anyway - up to you whetherb you take it
Mike

[kayjayd]

Originally Posted by mikey

The Getrag box comes nowhere near coping with that sort of power if used in any serious way. If you are using a set of Toyos or similar with an AA traction rating and you decide to use the power in 4th particularly on a slight incline you will destroy the first motion shaft, this is the weak component.

The Toyota Litace box (not the Supra Turbo) is slightly stronger at the first motion shaft mainly due to tighter Toyota tolerances, but even that comes nowhere near. I destroyed two Getrag and one Toyota gearbox before I had enough and purchased a Tremec which ended my worries. Until that point, I was always nervous about using the acceleration. The cost of the three gearboxes and the 2nd conversion kit meant I could have bought the Tremec in the first place.

In those motors where they are surviving, the torque will be being produced at a much later stage, so its more likely that the strain will not be as high. In the 409 it will come low down and as you should be making your shifts earlier to benefit from the cubes and gearing it will be taking significantly more stick.

If you can budget for it, go for the Tremec, otherwise you will always be gambling with potential failure. Looking at the cost of a decent 409 set up do you not think it is worth the extra.

Thats my advice anyway - up to you whetherb you take it
Mike

It's not a case of being worth the extra money as it most obviously will be, it's a cash of affording the extra as usual Stuck between a rock and a hard place really. Go for 350 bhp/ft-lbs and stick with the getrag or stretch the budget to get 450 bhp/ft-lbs with a tremec. The budget is not healthy currently hence the question of whether the getrag will cope with 450+ ft-lbs.

[TINKA]

Kev if your budget is tight now just wait for the unexpected costs to start cropping up. I started with £15-£20,000 and ended up nearer £25,000. If it that tight I would think again or be prepared to wait when funds run out for more to be forthcoming.

Cost me a kitchen and a deck in the garden

[mikey]

Its one of those situations where if you nurse it or drive it sensibly it will last. Its the one occasion when you get fired up as as a porker plays with you.

I think one of the other posts gave a good answer - if its only £150 then what do you lose really. You can start saving for a Tremec over a few years. Just dont drive it like you stole it initially.

Also if you get to a situation where you want to blow somebody into touch - then change up a gear and put less strain on the gearbox.

Mike

[Clarkson]

I have the same problem with my chevy, 433lbft torque bolted to a T5 gearbox, 100lbft over spec!! I think I will need to save up for a tremec ,but it might be ok in a light weight car.