having my engine built getting 2.5 conversion with sti4 heads froged bottom end 740cc injectors and aet 500 turbo etc avcr and like afp be mapping it just wandering if am better with a ppg kit for 5 speed box or going for 6 speed conversion whats pros and cons of both options?

 

first off your current box will shat itself first time you hit loud pedal, so good thinking that your gonna need a box.

main difference is cost and sound

basic options

6 speeder - prob around £2.5k (if new) for box diff etc
5 speed ppg - either helical or straight cut £3.5k

plus a clutch for both options.

6 speeder mucks around with the ratio's, some people like the change, some folks hate the change.

ppg kits are either helical or strightcut, with only a slight drop in capacity going for the helical, the difference is the noise, stright cuts whines, i have a 1-4 straight cut with a uk 5th for motorway cruising and works a treat, sounds awesome when you go up through the gears

 

As per Tidgy above,

PPG will retain your diffs whereas a sixer will need all them changing as well.

PPG ratios are also a touch longer than a standard box and you will retain your OE 5th gear.

As you have Sti 4 heads, I assume yours is a V4 car. Check your gearbox code (TY752 or TY754), if it is a TY752 you will need a donor 754 casing for c. £200 as PPG do not make a kit for the 752. The 754 is also stronger so worth doing.

PPG is also much lighter than a 6 speed so add that to the pros list.

Personally, I went for a PPG straight 1/2, helical 3/4 and P1 5th with the billet steel forks an Hyper Exedy twin plate.

For high torque applications, I wouldn't bother with a sixer as you will just be shifting all the time. Also, if your planning on 1/4 miles, it will add an extra shift which will slow your times.

 

i have a 6 speed conversion for sale at a very reasonable price - pm me

 

Fellas, when going with the PPG this means you can keep original diff yes?? my question, what power can the diff take,how strong are they really??

 

500 brake on a standard diff is very common. im sure someone with more knowledge will be along shortly with a more accurate figure

 

Really Jon?? better than i thought tbh...

 

there are plenty of people running 400 plus bhp on std diffs on here. i'm running 350 lbft of torque through my diff and its not complained.

 

No problem with my diff..

No idea what I'm running... Md321t @1.7bar on a forged 2.35 cdb.

 

think mine might have a leak form the seal and asked the question is it worth changing it. was told that the seals are dead easy to change, meaning not a costly job so not worth spending the £700 on an uprated diff, i then asked that if i want to go big ws it worth just biting the bullet and having one put in, was told the diffs good for over 600bhp (time attack cars run them no probs)

 

I ran my standard UK rear diff at circa 450bhp with no problems. This was after I wrecked one @ 350bhp because of low oil.

I'm also about to throw circa 600bhp through a Plated R180 4.444 Type R diff

 

Daz,

That,s some car/spec you have there fella, looks very impressive..

 

Cheers boys think ill go with the PPG kit by sounds of things wheres best to get 1 from? wifes gonna love is as just in middle of spending to much on engine as it is haha!!!! think ill go with a cusco twin plate not heard nowt bad with them and ill upgrade diff aswell.how how do bottom ends rev on 2.5 by way.

 

Try Scooby Clinic | The UK's Largest Independent Subaru Specialists | 01246 590 807 - Chesterfield S42 6QX or API

 

I found most price quotes to be the around about the same.

Typical of 14-16 hours of build/fitting time so you will have to leave your car there overnight at least. Based on this, I would take it to the nearest reputable specialist to make it easier for drop off and pick up.

Mine was built by Zak @ Mocom Racing in Essex (North Weald nr Harlow).

Would recommend David @ API who also has an excellent reputation and was helpful when I asked him a few questions.

Zen would be another top choice.

Good luck!

 

something to add, some specialist will have old cases nocking around that they can recon and use to build your new box then just change it out in a day.

 

Nice Spec you have there Rosi, what power is it making??

 

Thanks Pete,

Not really sure to be honest. Peaks at 1.7 bar and conservative estimate of around 450/450..

Quick pic..



You have a very nice looking Type R as well....

 

Rossi is that BK 18"s uve got on your car looks same as mine as i was wandering if they r are they ok for bigger brakes or u need spacers?

very nice type r by way

 

Looks stunning in that Pic Rossi, Black always does come up well...