most proven power on a 5 speed dccd
#1
most proven power on a 5 speed dccd
I'm looking to find out real world limits on the 5 speed dccd box in my 1999 Type R
I'm not looking for "it will cack itself over 330 brake mate", i'm looking for people who've been there and done it.
I know there are claims the dccd boxes are stronger, but also claims the gearset is the same as any STI. I'm aware that torque is the killer for gearboxes so i'm really looking for proven torque figures as well as bhp.
Due to the gearing, in my opinion the Type R is more of a b road, short track car where torque is more important than bhp. At the moment mine is running an enginetuner mapped 324/320 on the vf28 but this will all be getting changed soon and knowing the limit of the box will help which direction I go.
I'm not looking for "it will cack itself over 330 brake mate", i'm looking for people who've been there and done it.
I know there are claims the dccd boxes are stronger, but also claims the gearset is the same as any STI. I'm aware that torque is the killer for gearboxes so i'm really looking for proven torque figures as well as bhp.
Due to the gearing, in my opinion the Type R is more of a b road, short track car where torque is more important than bhp. At the moment mine is running an enginetuner mapped 324/320 on the vf28 but this will all be getting changed soon and knowing the limit of the box will help which direction I go.
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#10
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Not completely relevant but my normal 5 speed in a 53 blob ran 390 with similar torque for over a year and had some track and drag abuse. So they seem to take some stress despite what people say.
I don't really beat it around the rest of the time though.
I don't really beat it around the rest of the time though.
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There's people in the US running 700whp with the 6 speed and i can't see why they would make a weak 5 speed when they are capable of doing good things with gearboxs.
#15
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While there's a few that have run decent power through a 5 speed you need to remember the hundreds that have broke them at low power.
I broke one at 300 and one at 340, that was with normal fast road driving. I also ran north of 400 on another for a while before selling the car. I dragged it a few times and the new owner uses it on the track. Still going strong as far as i'm aware.
Classic 5 speeds are getting on a bit now unless they have had a refresh so asking one to work well outside it's comfort zone is asking for trouble.
Yes some hold up but many don't so don't think they are in the same league as a 6 speed. North of 400 90% of 5 speeds will break sooner rather than later. If you are ready for that moment then it doesn't matter. Just have fun while it lasts and then when it does **** itself stick a 6 speeder in there.
I broke one at 300 and one at 340, that was with normal fast road driving. I also ran north of 400 on another for a while before selling the car. I dragged it a few times and the new owner uses it on the track. Still going strong as far as i'm aware.
Classic 5 speeds are getting on a bit now unless they have had a refresh so asking one to work well outside it's comfort zone is asking for trouble.
Yes some hold up but many don't so don't think they are in the same league as a 6 speed. North of 400 90% of 5 speeds will break sooner rather than later. If you are ready for that moment then it doesn't matter. Just have fun while it lasts and then when it does **** itself stick a 6 speeder in there.
Last edited by MattyB1983; 25 December 2014 at 08:11 PM.
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Same box lasted me fine with a 20G and 20% methanol (never dynoed but I'm guessing easily 400 of each) for over a year as well including quite a few launches at some sprinty type things.
#18
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As far as I know alot of the issues are due to weak gearbox casings. Especially the early 752 boxes.
Theoretically if you were to brace the gearbox more it would probably withstand the power a bit better.
I seen gearbox brace kits before for the 5 speed on NASIOC and were apparently proven to work well.
Theoretically if you were to brace the gearbox more it would probably withstand the power a bit better.
I seen gearbox brace kits before for the 5 speed on NASIOC and were apparently proven to work well.
#20
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752 gearbox bell housings are only 4 bolt as opposed to the 754's 8 bolts.
The theory behind it is that it is better braced. It has less chance if flexing like the 752 box does. If it can flex, then the internals (gearsets) can move and this would have effect on the bearings and gear teeth I would imagine.
I've been reading up on how to strengthen 5 speeds without having to jump over to 6 speeds or PPG kits and it is possible. Although the power figures are a little strange to understand in the US, there are people over there running 500bhp or thereabouts on a 5 speed with a few choice mods with regards to bracing the gearbox.
I'd suspect changing the oil regularly (not sure if you can use a form of shockproof oil as I'm sure I read some of the shockproof stuff can be too thick), Group N or aftermarket gearbox mounts and additional case strengthening will help. I plan on doing this to my 752 box and see how much the bracing will make a difference after I up the power to circa 400 mark.
Also to add I have broken a selector shaft in my 752 Dccd box at around 300 bhp. This is more likely down to being heavy handed though.
The theory behind it is that it is better braced. It has less chance if flexing like the 752 box does. If it can flex, then the internals (gearsets) can move and this would have effect on the bearings and gear teeth I would imagine.
I've been reading up on how to strengthen 5 speeds without having to jump over to 6 speeds or PPG kits and it is possible. Although the power figures are a little strange to understand in the US, there are people over there running 500bhp or thereabouts on a 5 speed with a few choice mods with regards to bracing the gearbox.
I'd suspect changing the oil regularly (not sure if you can use a form of shockproof oil as I'm sure I read some of the shockproof stuff can be too thick), Group N or aftermarket gearbox mounts and additional case strengthening will help. I plan on doing this to my 752 box and see how much the bracing will make a difference after I up the power to circa 400 mark.
Also to add I have broken a selector shaft in my 752 Dccd box at around 300 bhp. This is more likely down to being heavy handed though.
#21
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I've also read quite a bit about these new gearbox brace plates that are available over in the US.
I'm still very dubious about them and don't fancy spending £300 plus shipping on a set.
The box also needs removing to fit them so if you aren't handy with the spanners it will prove to be an expensive purchase. And in reality it's just two lumps of steel bolted to each side of the box.
I'm still very dubious about them and don't fancy spending £300 plus shipping on a set.
The box also needs removing to fit them so if you aren't handy with the spanners it will prove to be an expensive purchase. And in reality it's just two lumps of steel bolted to each side of the box.
#25
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I've also read quite a bit about these new gearbox brace plates that are available over in the US.
I'm still very dubious about them and don't fancy spending £300 plus shipping on a set.
The box also needs removing to fit them so if you aren't handy with the spanners it will prove to be an expensive purchase. And in reality it's just two lumps of steel bolted to each side of the box.
I'm still very dubious about them and don't fancy spending £300 plus shipping on a set.
The box also needs removing to fit them so if you aren't handy with the spanners it will prove to be an expensive purchase. And in reality it's just two lumps of steel bolted to each side of the box.
I'm sure if you really wanted to try any means of preserving it you could get the gearset and casing cryogenically frozen ? I've heard of a few guys doing that too. But at the end of the day because not many people bother to try improving the 5 speed without swapping gearsets and moving over to a 6 speed it's not really commonly known if some of these ideas will work and are feasible vs. cost of 6 speed.
#27
#28
Exactly so it won't be that hard to get some ones made up. I can kind of see the idea, bracing the box further down before the centre diff. The 8 bolt 754 boxes are really only bracing the front of the casing better instead of the whole casing.
I'm sure if you really wanted to try any means of preserving it you could get the gearset and casing cryogenically frozen ? I've heard of a few guys doing that too. But at the end of the day because not many people bother to try improving the 5 speed without swapping gearsets and moving over to a 6 speed it's not really commonly known if some of these ideas will work and are feasible vs. cost of 6 speed.
I'm sure if you really wanted to try any means of preserving it you could get the gearset and casing cryogenically frozen ? I've heard of a few guys doing that too. But at the end of the day because not many people bother to try improving the 5 speed without swapping gearsets and moving over to a 6 speed it's not really commonly known if some of these ideas will work and are feasible vs. cost of 6 speed.
#29
Can't beat a bit of steel, to me the 5 speed boxes just don't have enough of it, gears are far too narrow and there is little support on the input/output shafts
#30
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Here's a link to the brace plates.
http://store.mooreperformanceparts.c...ru-blastplate/
Last edited by MattyB1983; 26 December 2014 at 06:37 PM.