Hi all, my first proper post so go easy on me

I am currently building a project car, which I should probably point out is a 4wd Peugeot (which I guess most of you in the US won't really be familiar with) not an Evo. I've managed to work out how to fit an Evo gearbox and transfer box into it to replace the crap chocolate boxes that Peugeot built.

Here is a link to my build thread on a Peugeot forum for those that are a interested! http://forum.205gtidrivers.com/index...9&st=0&start=0

To keep the conversion to the Evo drivetrain as simple as possible I want to use the original Peugeot rear diff. This is a full torsen unit and is actually very strong. I will be modifying an Evo prop to fit and Evo front driveshafts to fit Peugeot hubs.

I have bought a low mileage Evo IV GSR gearbox and transfer box, but I bought them before doing my research properly. Since then I have discovered that the Evo IV transfer box has a slightly different prop output shaft CWP ratio to my rear diff, and ideally it should be 1:1. The Peugeot torsen diff is 43x13 or 3.307. Now from what little information I have been able to find it seems that the IV TC has a ratio of 53x16 or 3.312. It also seems that the V and VI TC (mostly) have 43x13 ratios. If this is the case then I am thinking it would be prudent to swap the IV GSR box I have for one from a V or VI.

So, what I am asking is, can anyone confirm the information above?

If it is correct, is it safe to run different ratios (I am thinking not and will almost certainly swap) and if I have to swap is it worth paying a little more for an RS box with a front LSD, especially for a car that is purely for the track?

Thank you for you patience reading this and thanks in advance for any help you can give me!

Alex

 

i'm not sure on the ratios, but this should be an interesting project. good luck!! post some final pics

 

I feel sure youu can't run different diff ratios, they will spin at different rates and one will have to slip--if you had a center diff it would be that one and it would eventually burn up.

 

Thanks for the replies, I also think it will be very bad for the transmission to run different ratios. Does someone have a V or VI transfer box in pieces that they could count the number of teeth on the CWP to confirm this?

I will post up some pics of the finished project, I am currently getting an adapter plate machined up to mate the gearbox to the Peugeot engine!

 

link doesn't work.

 

Yeah whoops, all fixed now!

 

evo 4 -9 boxes all have the same 4.53 final drive. so it wont help you to switch to v or vi box. they are the same ratios. the 3.307 and 3.312 are close enough to be interchangable. you are good to go using your rear end with any of the evo gearboxes. and actually its the transfer box that needs to match the rear end. you can put any final drive you want in an evo trans and not make any changes to t-case or rear. thats the beauty of them. if you are using a small diameter tire you can use hks 4.11, m factory 4.0, or tre 3.73 to get longer gear ratios. or if you want a tractor puller you can use the factory 4.86 for ultra short gearing.

cool project, have fun!

 

Ahh yeah, that is true, but the CWP I was wanting info on was the one in the transfer case. I know that the transfer case and rear diff ratios need (ideally) to be 1:1, and from what I know using the Evo IV transfer case with my rear diff it will not be truly 1:1. But if I were to use a V or VI TC then from what I think I know it would be the same ratio. I just wanted to know for sure before I sell me IV TC and buy another one.

The overall final drive in the gearbox is useful and very easy to switch as you say. The original Peugeot transmission had the same layout, with the final drive in the gearbox, but the Peugeot transfer case contained both the front and rear diffs and the VCU - it breaks quite often Hence why I am going through all this!

 

the transfer boxes 4-9 have the same gear ratios.
the 4-6 are not interchangable with 7-9 only because of output shaft geometry. the 4-6 case output shaft goes under subframe. the 7-9 cases go over the top of subframe. the cases all bolt to transmission the same way. you can use 4 trans in evo 9 and visa versa. but you cant swap tcases.

the evo 8 tcases are stronger and have a beefier output shaft. but the 4-6 cases will be easier to work with. driveshaft yokes are also different between 4-6 and 7-9. the hypoid gears in evo 7-9 are more extreme then 4-6. it is therefore subject to ring and pinion that wear out prematurely. we call it the death whine. the 4-6 case gears dont suffer from this.

 

OK, I found a website with the following information on it about rear diff ratios:

Evo 4 runs 3.312 (both GSR AYC and RS LSD) 1996-1997
Evo 5 runs 3.312 (RS LSD ONLY) (SNGF)
Evo 5 runs 3.307 (GSR AYC ONLY) (SDNF) 1997-1998
Evo 6 runs 3.307 (both GSR AYC as RS LSD) (SNDF SNGF SNGF2) 1998-2000

(http://www.mivec.co.nz/forums/viewtopic.php?f=34&t=7129)

If this is true and the ratio from the transfer box to the rear diff must be 1:1, then it means I can use an Evo 5 GSR transfer box or an Evo 6 GSR or RS. If this is the case then I am going to buy an Evo 6 RS transfer box and use the LSD to cut out some understeer

 

dude seriously. 3.307 is same ratio as 3.312. it only differs by .005.
uneven tire wear front axle to back axle will create a larger difference in wheel speed than that in about 200 miles of driving. front tires wear faster than the rears.

 

true, but I still want an LSD and I can get an Evo 6 RS box for a good price so there is no reason now not too! Thank you for giving me some feedback though and taking time to answer my banal questions!

 

I know this is dragging up an old thread of mine but here are some pictures of my Peugeot/Evo hybrid as it currently stands. The boxes are all in with an adapter plate. I am running a Quartermaster clutch kit on a modified Peugeot flywheel to accept the 7.25" clutch. The flywheel face may need offsetting to allow the plates to engage on the gearbox output shaft sufficiently.

I have had a full custom solid gear linkage made that works beautifully. The front driveshafts are Evo 6 ones that have been modified to fit the Peugeot front hubs. The front half of the prop is also an Evo 6 one with a custom centre bearing and the rear half of the Peugeot prop mating to the original Torsen rear diff.

I hope you like the pictures!

 

That's bad ***. I love intelligent swaps.

 

Hello man. Backt to the life this thread.

Last year in a drag race I broke my open diff (tcase) and rear diff (AYC) in my Evo 4.

I buy an Evo V tcase and swap an Evo 9 rear diff (LSD). The car runs perfect without issue, until this last saturday. I launch my car and when out the clutch feel like the clutch spin and hard knock in the rear diff.

The car run in straight line but when I turn left or right is the problem, the car not move. Yes, I now its the open diff (broke spiders gears), and I think the clutch slips because the car not advance after a while.

My question is, What could have happened? this was the first lanuch I made with newly assembled parts? Theres is not compatible the ratios???

Im very dissapointed!