tinysq

iTrader: (1)

I have a classic wrx with about 330 bhp and 320 lb/ft, my standard 'box is moaning about this so want a better box.
I recently read i the total impreza mag that someone is running near 700 bhp with a standard sti6 box with dccd, what figures are the limits on these boxes and what would i need to put one in my car?

Fat Boy

They're either running straight cut PPG gears in a classic case ( circa 2.5k fitted) or they're fibbing or it's a 700bhp/ 12ftlb torque engine

The dccd doesn't make any difference either way really - it's tough in itself but it's the main part of the box that lunches itself if you're going to have a problem.

Circa 350 bhp is seen as the rough rule of thumb limit for later classic 5 speed boxes with the 6 speed boxes being much tougher.

Having said that I'm currently running a normal 5 speed with dccd and uprated clutch/flywheel with a 450bhp/400ftlb engine and so far so good. I don't do drag strips or traffic light GPs and it will go eventually but so far so good.

tinysq

iTrader: (1)

what other boxes had the dccd that i could use just as an option?

rob4620

The Zen Impreza runs a JDM 6 speeder with 700bhp.

Fat Boy

RCM Gobstopper too.

If your car is a JDM wrx calssic then you'll have a 1;1 transfer box so you'll be looking at JDM dccd s really.

Welloilbeefhooked

iTrader: (3)

I thought that all dccd boxes were JDM (except 6 speed)?

tinysq

iTrader: (1)

now im just confused

Fat Boy

True (ignoring 22b uk or the uk P1 - which has 1:1 transfer gears as it's really a jdm StiV or Vi in drag) but more where I was coming from was whether your car was a jdm WRX or a UK classic. I couldn't be faffed to double check your scooby Some people use "wrx" to mean classics whereas it's really the JDM version.

So,assuming yours is JDM, then the classic dccd diff and transfer gears should fit. Phase 1 and phase 2 dccds as well in classics if you want to get really confused I think that both fit but Api or Zen would know the answer to that

harvey

iTrader: (48)

The STi 5,6,P1 box is pretty tough but not as tough as the Six Speed box or the PPG. This is probably in part because the casing, 754 is more rigid than the previous 752. I am currently running three of these boxes at 371, 422 and well over 550bhp. However it is torque and not bhp that breaks gearboxes.
New Age cars, WRX five speed cars all run TY754 boxes.

The DCCD is not unbreakable and has nothing to do with the gearbox strength per se so fitting a DCCD will not make your gearbox last longer.

Fit a 752 DCCD to a 752 casing and a 754 DCCD to a 754 casing.

tinysq

iTrader: (1)

ok ive gone from slightly confused to in the middle of the atlantic, im well out of my depth.
my car is running about 330 lb/ft of torque but im hoping to upgrade the turbo and injectors in the future.
what box can i run for as little as poss which will take it (i do like to use my car on track so it gets a hard life) if poss i would like a dccd as i can run more power through the rear wheels when i want for a little fun?

harvey

iTrader: (48)

Sorry. That was not the intention.
What year of Classic and what model/JDM/UK etc.
The TY752 boxes fitted to cars up to and including M/Y 98 are not as strong as boxes fitted to cars, M/Y 99 onwards. TY754. (five speeds)
In my experience, once you have 330ft/lbs on a TY752 it is only a matter of time before it breaks. Usually third gear and sometimes second. A lot has to do with driver style and mechanical sympathy.
The TY754 boxes are generally stronger, possibly because their casings are more rigid and from first hand experience I know that STi 5 and 6 boxes will handle a lot more torque than that which breaks the TY752 boxes.
Fitting a DCCD in place of the viscuous centre diff will make little or no difference to the strength of the box itself and the DCCD is not ultra strong anyway. There is the additional cost and complication of the electronic controller.
New Age STi 6 speed boxes are stronger still but there is a weight penalty. Also consider you will have five gear changes to get to where you can on a five speed with four changes. PPG helical gear kits appear to handle lots of torque and are acceptable for a road going car.
I hope this brings a bit of clarity.

Welloilbeefhooked

iTrader: (3)

You know too much!!!

tinysq

iTrader: (1)

yes it does thankyou, my car is a 1995 wrx jap import with forged psitons and wr bearings, 550cc injectors, fmic, greddy profec b, apexi power fc, exedy lightened flywheel and uprated clutch, i run in addition redline heavy duty shockproof gear oil in the box just so it lasts a little longer. i just need a stronger box but dont want anything too noisy i.e the whine i hear you get from a ppg box

Fat Boy

PPG comes in straight cut (very whiny) and semihelical flavours (virtually same as OEM) and a combination can be fitted eg 1,2, 3 straight cut 4& 5th helical for instance so it doesn't need to be that noisy all the time. Dccd has no bearing on any of this as it hangs off the back of the main gearbox

tinysq

iTrader: (1)

how much are the ppg gears tho?

Fat Boy

Loads... £2.4k or so plus fitting, I think. Cheaper to sort a 6 speed, but it's all swings and roundabouts

tinysq

iTrader: (1)

ok cheers mate

rossi_p

iTrader: (26)

As yours in a MY95 car it will have the TY752 box as mentioned by Harvey. PPG do not do a kit for this casing so you will also need to buy the TY754 casing (c. 150+VAT).

The PPG set costs c. 2000 + VAT so about 2,350. That is just the gearset 1-4 though as you will keep the OE 5th. As mentioned you can select straight or helical gears. I have a straight 1/2 and helical 3/4 in mine. I'm not sure what 5th gear ratio you have but if it is short (like on my type R), you will probably want to get a UK 5th. This is because the PPG gears are longer than the standard gears (in a type R anyway) and 4th will be too close to 5th to make much difference.

Factor in selector forks (320+vat), oil, gaskets, seals, and you're looking at c.3000k. You may also have to replace bearings... Could be another 200+

You already have an uprated clutch, but depending on how far you go with engine tuning you may need to step up to twin plate land so possibly another grand for a clutch! Unless your clutch is in good condition, I would suggest a new clutch anyway whilst the 'box is out.

Unless you are building it yourself, then you will also have to factor in labour. 12 hours I believe is the standard build time (4 hours to strip/refit, 8 to build). So minimal 700 to fit (inc vat)...

Excluding a clutch, you're looking at least 4k....