Discussion
I expect you know that the T56 is used in a variety of high powered machines such as the BMW M series cars, Mustangs, Vipers, Holdens etc. From what I have read they're reliable with up to around 600bhp running through them. A range of stronger internals are available to handle up to 900bhp. A lot depends on whether you're driving on the street, drag racing or circuit racing. I think the first point to go isn't the gears themselves but the selector parts in the box. Try searching through the C5 Tech section of Corvetteforum.com and you'll pick up some useful information.
Very good trans, I have used the T56 on a couple of projects with great success.
As with all transmissions its not the BHP that kills them its the torque, its worth rebuilding the trans with higher spec synco cones especially on 1st and 2nd gears. There is also a higher spec bearing set available for the 1st and 3rd motion shafts which is worth fitting.
As with all transmissions its not the BHP that kills them its the torque, its worth rebuilding the trans with higher spec synco cones especially on 1st and 2nd gears. There is also a higher spec bearing set available for the 1st and 3rd motion shafts which is worth fitting.
With the T56 there have been some reported problems of people bending the gear selectors through hard (mis) use. Can't remember if it was a Corvette or a Viper problem as one has aluminium bits and the other one doesn't.
I believe the Corvette uses a transaxle consisting of the gearbox and the differential. Not sure whether the T56 refers to the transaxle or just the box. My learned friend in all things Corvette Mr. Blackzr will surely know the answer to this one.
I believe the Corvette uses a transaxle consisting of the gearbox and the differential. Not sure whether the T56 refers to the transaxle or just the box. My learned friend in all things Corvette Mr. Blackzr will surely know the answer to this one.
I know some upgraded Corvettes have had problems with the selectors, I'm sure the Viper guys will tell you about any problems on their machines.
The T56 is just the gearbox reference, the diff would have it's own ref. Although the box and diff are bolted up to one another on the Corvette they do not share fluids and can be upgraded or replaced separately.
There are two sets of gearbox ratios in the Corvette. I have a C5 Coupe with what GM refer to as the MN6 gearbox which has ratios 2.66, 1.78, 1.30, 1.00, 0.74 and 0.5:1. Vetteheadracer has a C5 Z06 which has what GM call the MN12 gearbox which has ratios 2.97, 2.07, 1.43, 1.00, 0.84 and 0.56:1
Someone told me that the 5th and 6th ratios come as a pair so you would not be able to mix the gears to have 5th being 0.74 and 6th being 0.56. I don't know if this applies to the other pairs of gears too and what you can poach from boxes made for other car manufacturers.
The T56 is just the gearbox reference, the diff would have it's own ref. Although the box and diff are bolted up to one another on the Corvette they do not share fluids and can be upgraded or replaced separately.
There are two sets of gearbox ratios in the Corvette. I have a C5 Coupe with what GM refer to as the MN6 gearbox which has ratios 2.66, 1.78, 1.30, 1.00, 0.74 and 0.5:1. Vetteheadracer has a C5 Z06 which has what GM call the MN12 gearbox which has ratios 2.97, 2.07, 1.43, 1.00, 0.84 and 0.56:1
Someone told me that the 5th and 6th ratios come as a pair so you would not be able to mix the gears to have 5th being 0.74 and 6th being 0.56. I don't know if this applies to the other pairs of gears too and what you can poach from boxes made for other car manufacturers.
Thanks, I just want to see what the options are, as I will require a strong box.
The 6 ratios doesnt appeal that much, but if its strong, then Im ok with it.
It will be used primarily as a road car, but I will be drag racing it too.
It will be some time before I am ready to buy anyway, as I have to sort a new engine first.
Anybody wanna see a 1980 Granada, with a twin turbo LS6 engine ? Im getting rid of the old rover engine soon, in favour of something a little stringer, and more modern. Already have a short motor, + new forged pistons, courtesy of BoostedLS1, although just not too sure of the origins of the engine. It seems to be an LS6 block, but with a Camaro sump. Anyway, it all looks good to me
I might be ready for TOTB3, but just depends on how the finances go.
The 6 ratios doesnt appeal that much, but if its strong, then Im ok with it.
It will be used primarily as a road car, but I will be drag racing it too.
It will be some time before I am ready to buy anyway, as I have to sort a new engine first.
Anybody wanna see a 1980 Granada, with a twin turbo LS6 engine ? Im getting rid of the old rover engine soon, in favour of something a little stringer, and more modern. Already have a short motor, + new forged pistons, courtesy of BoostedLS1, although just not too sure of the origins of the engine. It seems to be an LS6 block, but with a Camaro sump. Anyway, it all looks good to me
I might be ready for TOTB3, but just depends on how the finances go.
Theres some good replies above onratios and soforth, my research on 4th Gen Camaros and the tuning of them (see forthcoming Street Machine magazines) found that 550bhp is about where you can get to on a stock T56 before you may run into problems. I guess for torque you'd be looking at about 500 lb ft.
I'm thinking of building a LS1/6 for drag racing too. But I found that a better and stronger alternative is to use the 4L-60E auto trans, which is a 4 speed, and then use a Gear Vendors overdrive unit, effectively creating 8 forward ratios. You also get semi auto control. 8 speed semi auto, strong enough for 1200 bhp...nice. You could also use the TH400, and an overdrive unit, but since you start with 3 gears and then double it you only get6 forward ratios.
[url]www.gearvendors.com[/url]
I'm thinking of building a LS1/6 for drag racing too. But I found that a better and stronger alternative is to use the 4L-60E auto trans, which is a 4 speed, and then use a Gear Vendors overdrive unit, effectively creating 8 forward ratios. You also get semi auto control. 8 speed semi auto, strong enough for 1200 bhp...nice. You could also use the TH400, and an overdrive unit, but since you start with 3 gears and then double it you only get6 forward ratios.
[url]www.gearvendors.com[/url]
It was my Granada with the rover engine at TOTB. Im not sure what times to expect really. To be honest, I dont see myself getting into the 10's, as weight and cost are against me ( car + driver is 1580kgs ). While I may try and lighten where possible, I am not going to butcher the car, or remove any of the trim etc to do so. It is primarily a road car, and it will stay that way. It will also always be driven to and from any events.
Given a std LS6 makes around 400bhp, I see no reason why 750-800bhp shouldnt be possible. That may take a while, as I will be using some bits I currently have to keep costs down, like fuel system and turbos. This may limit me initially to around 600-650. I think the turbos will do that easily enough, but my fuel system will be at its limit, for both pump, and injectors.
Traction is a major problem at the minute, as are driveshafts breaking. I have a Ford 8.8" axle that I will be fitting over the winter, so I think this should help strength, and hopefully give me a lot more traction, alng with bigger tyres.
At TOTB, i was getting around 2.3s 60ft times at best. I have been at Crail, and Santa Pod since, but best I could get was 2.5's. But im losing traction for a lot more than 60ft.
Steve Scotts white Focus I mention in the other thread is launching amazing 1.7s 60ft times. Id like to get mine under 2s.
My car does have enough power to get into the 11's at the minute I think, I just cant get grip.
At TOTB, my terminals were consistent around 118-120mph. At Crail, and Santa Pod ( 2 runs at Pod before breakage ) again they were around 115mph, despite the huge wheelspin issues. Of the 2wd cars that went quicker, I think my terminals were higher than most.
Given a std LS6 makes around 400bhp, I see no reason why 750-800bhp shouldnt be possible. That may take a while, as I will be using some bits I currently have to keep costs down, like fuel system and turbos. This may limit me initially to around 600-650. I think the turbos will do that easily enough, but my fuel system will be at its limit, for both pump, and injectors.
Traction is a major problem at the minute, as are driveshafts breaking. I have a Ford 8.8" axle that I will be fitting over the winter, so I think this should help strength, and hopefully give me a lot more traction, alng with bigger tyres.
At TOTB, i was getting around 2.3s 60ft times at best. I have been at Crail, and Santa Pod since, but best I could get was 2.5's. But im losing traction for a lot more than 60ft.
Steve Scotts white Focus I mention in the other thread is launching amazing 1.7s 60ft times. Id like to get mine under 2s.
My car does have enough power to get into the 11's at the minute I think, I just cant get grip.
At TOTB, my terminals were consistent around 118-120mph. At Crail, and Santa Pod ( 2 runs at Pod before breakage ) again they were around 115mph, despite the huge wheelspin issues. Of the 2wd cars that went quicker, I think my terminals were higher than most.
JenkinsComp said:
I'm thinking of building a LS1/6 for drag racing too. But I found that a better and stronger alternative is to use the 4L-60E auto trans, which is a 4 speed, and then use a Gear Vendors overdrive unit, effectively creating 8 forward ratios. You also get semi auto control. 8 speed semi auto, strong enough for 1200 bhp...nice. You could also use the TH400, and an overdrive unit, but since you start with 3 gears and then double it you only get6 forward ratios.
[url]www.gearvendors.com[/url]
I was going the 4L60 route as well but my research indicated it wasn't all that strong and people on some of the US forums were steering me away. I though next about a 4L80 or TH400 but weight was concerning me. Once I found some good reports for uprated T56's I went back to that plan. I think I saw the gearvendors site but realised I didn't have room for the overdrive unit on the back of the gearbox. Mind you, I would have had a propshaft of about 6" if I went that route.
What car are you thinking of using, if you don't mind my asking?
An auto may suit a drag car, but for a performance road car......No thanks.
So far anyway, opinions on the T56 are good, and if need be it does have available upgrades which is good.
I see also the Tremec 3550 TKO II 5 speed is rated at 525lbft
If thats what they rate it at, then im sure it will ahndle a lot more, given the T56 is rated at 450lbft.
So far anyway, opinions on the T56 are good, and if need be it does have available upgrades which is good.
I see also the Tremec 3550 TKO II 5 speed is rated at 525lbft
If thats what they rate it at, then im sure it will ahndle a lot more, given the T56 is rated at 450lbft.
JenkinsComp said:
What car are you thinking of using, if you don't mind my asking?
A Sylva Striker (Caterham 7 type kit car)
Yes I'm mad, it'll either take off or snap.
But I may use a late Camaro. They're too heavy,but might not snap.
Your as mad as one of my customers. I've got an LS1 is going into his Westfield SE8 and we're certain it will fit! You to should get together but not on a corner.
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