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 was running 410 in my old v6 type r limited

Thats good to know Stu, torque i presume? for how long?

How long it last will depend on how you drive it, miss a gear and could kill it even down around 300. mechanical sympathy goes a long way.

380 , it was running they power well over a year
not a problem
but I did drive like a fanny lol ;-)

A friend of mine is running 502 on a Version 6 Type R box, has been for over a year. Prior to that, 410 on the same box for quite a few years.

Not bad for a track car ;)

I think engine tuner ran over 500bhp and tracked and dragged it. I'm sure Martin will be along to confirm.

ok WOW I wasnt expecting people to say numbers that high!

Looks like i'll be keeping the box in for now and going 6 speed once it decides enough is enough. It will get trackdays and santa pod so we'll see how long it lasts on 400ish.

Goes in the face of a certain someone that says all 5 speeds are ****e and that the 6 speed is the best gearbox ever made! :lol:

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.

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.

https://www.scoobynet.com/general-te...er-limits.html

Martyn's comments in this thread

I have run 480 through a ppg 5 speed for years, up rated 5 speed i know :lol1: that's with totb thrown in lol

440bhp/ 380 ft lb / 18k miles on a 5 speed DCCD. Fast road, track. No drag or launch control stuff, but used hard otherwise.

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 sh1t itself stick a 6 speeder in there.

I broke a 5 speed at 400ish

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.

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.

I'd like to know how that actually works. I've read that the 754 casing (which I have) is stronger than the 752 but how does this affect the overall strength of the box? surely its whats inside that handles the power, not what you put it in??

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.

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.

Which box does the v3/v4 sti have please?

Cheers for the info, so is it worth considering these as an upgrade?

http://www.ebay.co.uk/itm/Subaru-Imp...item19cec5ef27

V3 and V4 cars still used the 752 box.

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.

Iv run 330bhp throught my v5 type r box with no problems for the last 12 months thats in a sprint car with about 20 full lauchs per event and driven hard its still going strong

Good point Dunk - I forgot that I had sold it on to you when I went 6 speed.

Not sure about the freezing thing, i'm just curious if that gearbox mount/brace I posted a link to is a good idea? Would give more support to the centre/rear away from the bellhousing.

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

Your link isn't for a brace, it's just an uprated mount. I honestly can't see that helping to prelong the life of a box. I'd rather use that £110 and do a oil change using the best redline stuff available.

Here's a link to the brace plates.

http://store.mooreperformanceparts.c...ru-blastplate/