Many people think you need to change the rear diff to suit a P1 box but you don't. The box will be a straight swap.
You don't need to even think about this yet, just something to bare in mind if you ever have any problems.

Harvey, P1 box code is TY754VBAAA

 

its definetely a good cheaper option as it will always break when funds are tight.thanks for the info matty!

 

+1 , similar spec as vf28 bar different wastegate

 

You do sometimes get exceptions to the rule, my 28 made 342 at 1.5 bar. That was at zen so is pretty accurate reading.

 

To be sure on that question I need to know your model and year.

 

if you are reffering to the p1 gearbox being a straight swap,then my car is a 1998 impreza sti type r v4..if a straight swap is fine then definetely is a good option.

 

Yes I suspected you had an STi 3 or STi 4 from skim reading this and both of these are 4.44 rear diffs and the P1 is 4.44 so all you need is a P1 box or STi 5 or 6.

 

thanks harvey,are all those boxes the same?
what power/torque will they take?

 

Hi mate, I've just changed my turbo to a 20g and a 16g came off it and it was running approx 330bhp!

 

hi,yours is a v5 isnt it?
are you expecting the box to hold out with a 20g?
370 bhp??

 

Driven intelligently the P1 / STi 5/ STi 6 box will handle everything you will ever get out of a 20G. My STi 6 box was running well over 500 bhp in the STi 6 Wagon and did lots of drag starts including winning Scooby Shootout some years ago. That same box is now in my 95 WRX somewhere around 450/460 bhp. The only thing that has ever been changed is the viscuous diff, twice, once because a clown called Pete Croney fitted a rear diff with a 3.9 ratio when the front diff is 4.44, what an idiot and the second time because the replacement viscuous became very noisy. I have not broken any gears or synchromesh and guess the box will have done a total of about 60000 miles.
Do not fit a paddle clutch. Stick with heavy duty organic. It is the shocking on the transmission that kills the gearboxes

 

thats,thats great news and i appriciate the info,i had the dreaded thought of having to part with 2k when mine breaks for a six speed.
do u know the part numbers of the 3 boxes which are a straight swap? i would never be running over 400 bhp.
thanks very much harvey.

 

P1 box number is above in my earlier post.

 

Thanks Matt.
The box in P1/STi 6/Sti 5 is all the same part number.
The TY754 VBCAA will also fit.
I suspect this has lower gear ratios and will check later but rear diff is the same so you can use it.

 

Some more information to widen your search.
The P1 box STi 5/STi 6 has a relatively low first gear of 3.166 and .738 fifth gear which reduces revs on motorway cruising at the expense of a little bit of accelleration but higher top speed. All the following boxes share the same ratios:
VBAAA, VBBAA, VB4AA, and VBCAA.
All have 4.44 rear diffs as do the following but they have lower top gears so more accelleration and less top speed. They also have a higher first gear giving more speed in first than the other boxes:
VB1CA, VB1BA, VB1EA.
I hope this helps you find the box you need.

 

Not sure yet mate, I'll let you know tomorrow mine is a TY754 so stronger than the 752! I've got the supporting mods plus a SimTek so fingers crossed for a good run! I just miss my 6 speed

 

would the TY754 VBCAA be from the v5/6 type r as i do like the low ratio box.?
thanks harvey.

 

bump for harvey

 

I believe that Type R gearboxes or perhaps RA gearboxes have a longer first gear and then close ratios through to 5th and that in 5th they are .825 as opposed to .738 on P1 STi 5/6 etc. but if you find the gearbox and get the number I will try and help you further.

 

ok,well when mine eventually breakes i would like the same box as whats on my type r but one that will handle the power,do you know if the v5/6 type r boxes are the same ratios as my v4 type r?

 

Let me have the TY752 number on your existing box. It is on a sticker on the bell housing and you can see it from the engine bay. If the box has not been changed the number is also on the VIN plate.

 

the number on the bell houseing is...
TY752VB5CA
it is also the same number on the VIN plate.

 

Your box is the same box that is on my STI V3. The P1 box has exactly the same ratio's through 1st to 4th with a very slightly longer 5th.
I am going with a P1 box as I love the close ratio of my current box but could do with a slightly longer gear when cruising. P1 box fits the bill for me perfectly, and the fact that it is a direct box swap is even better.
Remember it's also quite a bit stronger than the boxes we are both currently running.

 

sounds good matty,a silky smooth plan for the future.

 

so all the dccd works the same etc?

 

Ahhhhhh, forgot that the type R has DCCD. My car doesn't run DCCD and nor does the P1.
In that case the P1 wouldn't be any good to you if you want to keep DCCD. You may have to go V5/6 route...

 

thanks mate,wheres harvey when u need him?

 

harvey??

 

What is the question???
The DCCD from a 754 box will fit any 754 box if you have the switch and electicals to go with it.
The DCCD from a 752 will swap on to a viscuous 752 also but a 752 DCCD will not fit a 754 box and vice versa.

I have a TY754VBAAA for sale. Only came out of the car to fit a six speed. In perfect working order. £400. Will fit £155. I also have 4.44 rear diff if required.

 

my box is TY752VB5CA
i want to know which gearbox that is stronger will be a straight swap without any messing about and dccd works as normal.thanks.