Lengthening Gearing On 205 Turbo

[bales 1]

One of my main mods i am planning to do over the next few weeks is to rebuild a spare be3 1.9 gearbox I have as mine is getting a bit notchy and crunchy even with new gear rods so I think it is the synchro's going. There is quite a bit of talk about using a longer final drive which is my intention, where do people source these from though? is it a matter of going into scrappies and taking apart gearboxes or is there places they can be bought from for not silly money, or do any kind people have them already hanging around that I could purchase off .

 

Also what final drive (and out of what vehicle) do people recommend for this, I shall be running about 12-14psi of boost very shortly and its just too short geared at the mo, 2nd is literally on boost for a few seconds then it goes flat straight away as 5k rpm is all it seems to like to rev to effectively. So for matters of traction and driveability I think a longer gearbox would be better than trying to get more power! (didn't think I would ever say that lol) so any pointers to what to use and where to find them would be much appreciated.

 

Thanks

 

Alex

[sutol 0]

Quick and easy fix I think would be a 205TD gearbox, what does anyone else think ?

[bales 1]

So I take it a Td gearbox is a BE3 and will bolt straight on, never really thought about changing the whole gearbox to be honest, would it not be too long geared with a Td gearbox, anyone have any info on ratio's??

[Anthony 1,000]

anyone have any info on ratio's??

From memory, very roughly the TD 'box ratios as follows:

 

1st = 5mph/1000rpm

2nd = 10mph/1000rpm

3rd = 15mph/1000rpm

4th = 20mph/1000rpm

5th = 25mph/1000rpm

 

That makes TD 4th about the same as a 1.9 5th, to give you some idea. HDi 'boxes are longer - roughly 30mph/1000rpm in 5th from memory.

 

A TD box from a 205/309 will bolt straight on, but from other models (306 etc) you'll have to change the selector arm and possibly the clutch arm and fork (if it's a pull type clutch)

[pug_ham 240 3 Cars]

I agree with the ratios Anthony has listed for the TD gearbox, mine is doing slightly lower rpm in fourth than a 1.6 GTi box gives in fifth.

 

Henry Yorke has a hybrid gearbox on his turbo skip, basically an Mi ratio gearbox with the 3.688 1.9 FD.

 

This gives you standard 1.9 ratio's for first thru third & longer fourth & fifth so cruising is nice & relaxed.

 

It won't be far off the ratio's of the TD gearbox so thats the easiest choice for an easy swap.

 

Graham.

[bales 1]

Thanks for the info on that, seems like a Td gearbox might be the easiest solution. I should point out that it isn't really a road car so what it revs at on the motorway isn't really the main consideration for this.

 

The main problems are traction and having to change gear so bloody often, in the wet it spins up in second regardless of what the surface is like and that is with Toyo T1-Rs and on coilovers so it doesnt squat much at all to take the weight off the fronts and thats only running standard boost.

 

It is a trackday car, and I know people usually shorten the gears if it isnt a road car, though I do think that if mine got to actually stay in the gears longer it has more than enough torque (or will when at 14psi) to pull longer gears and would actually be quicker . Then again there isn't that many people who seem to use the turbo engine in a track car so I guess there isn't many people with direct experience of this.

 

Anyway thanks for the info

 

Does anyone have or know of a Td gearbox I could take off their hands?

 

Alex

[bales 1]

Henry Yorke has a hybrid gearbox on his turbo skip, basically an Mi ratio gearbox with the 3.688 1.9 FD.

 

This gives you standard 1.9 ratio's for first thru third & longer fourth & fifth so cruising is nice & relaxed.

 

The problem with this is I want a longer 2nd and 3rd as thats where I get all the wheelspin and struggle, top speed doesn't bother me so 4th and 5th arent that important.

 

Think Td box sounds decent at the moment, I take it that they bolt on fine and that a mi16 clutch will fit as that is what I am using at the moment, thanks.

 

Alex

[Anthony 1,000]

If funds stretch to it, wouldn't you be better with an LSD rather than longer gearing for traction? For purely track use, I'm not sure that a longer gearbox is the answer unless you're running out of revs/boost in 5th on the straights on faster tracks like Combe and Donington...

[bales 1]

If funds stretch to it, wouldn't you be better with an LSD rather than longer gearing for traction? For purely track use, I'm not sure that a longer gearbox is the answer unless you're running out of revs/boost in 5th on the straights on faster tracks like Combe and Donington...

 

That was pretty much the conclusion that I was coming too really after reading back what I had written, your probably right...but I do drive it on the road aswell and I can't really afford £500 at the moment.

[205turbo 32 2 Cars]

i have used a late 306 Dturbo box on mine,

 

But i'm a bit worried as the new turbo will push up to 7.5k on boost, so i may end up puting a 1.9 box back on as i'll be over geared

[leon 1.9 0]

From memory, very roughly the TD 'box ratios as follows:

 

1st = 5mph/1000rpm

2nd = 10mph/1000rpm

3rd = 15mph/1000rpm

4th = 20mph/1000rpm

5th = 25mph/1000rpm

 

That makes TD 4th about the same as a 1.9 5th, to give you some idea. HDi 'boxes are longer - roughly 30mph/1000rpm in 5th from memory.

 

A TD box from a 205/309 will bolt straight on, but from other models (306 etc) you'll have to change the selector arm and possibly the clutch arm and fork (if it's a pull type clutch)

 

My 306 HDi pulls about 90 at 3000rpm (obviously on a racetrack...) so must be about 30mph/1000rpm.

 

Of topic, need to ask you Anthony about boot locks on 306s (think I need one).

[pug_ham 240 3 Cars]

The problem with this is I want a longer 2nd and 3rd as thats where I get all the wheelspin and struggle, top speed doesn't bother me so 4th and 5th arent that important.

 

Think Td box sounds decent at the moment, I take it that they bolt on fine and that a mi16 clutch will fit as that is what I am using at the moment, thanks.

 

Alex

In that case imo the TD gearbox isn't suited, first gear is actually lower than than in the 1.9 GTi box.

 

Second & above are all slightly longer but to fit a longer first to a TD box (1.9 Gti would suit) means a full gearbox strip to swap which could cost almost as much as a diff unless you DIY.

 

Graham.

[whizzer71 0]

Well guys from personal experience (Marks car) what you want is a 3.47 diff (205 D) 1.9 Gti 1st & 2nd xsara vts 3rd & 4th with a 1.9 Gti 5th,Makes the best use of the torque right across the range in each gear !,coupled with a quaife = ultimate turbo box !,still have traction issues in the wet but thats all down to the sheer grunt !

 

2.92 , 1.85 , 1.28 , 0.95 , 0.87 3.47 diff

 

[trialster 0]

on a similar note, how easy is it to swap a final drive gear over?

 

the reason i ask is because i have a 1.9 gti car and wish to use a 1.6 gearbox with it whilst retaining the 1.9 FD.

 

ta

[pug_ham 240 3 Cars]

on a similar note, how easy is it to swap a final drive gear over?

 

the reason i ask is because i have a 1.9 gti car and wish to use a 1.6 gearbox with it whilst retaining the 1.9 FD.

1.6 & 1.9 gearboxes are as good as identical apart from the final drive & first gear.

 

Its pointless to change imo, just use the 1.9 gearbox.

 

Graham.

[trialster 0]

1.6 & 1.9 gearboxes are as good as identical apart from the final drive & first gear.

 

Its pointless to change imo, just use the 1.9 gearbox.

 

Graham.

 

ok point taken, but im taking the gearbox off anyway to change the clutch.

 

any idea how easy/hard it is to change the final drive over? i might be able to lay my hands on a longer FD to lower rpm on motorways than the 1.9 box..

[TT205 42]

Don't forget, you can't just swap the FD, you have to swap the pinion over as well - so as Graham says you will have to crack both boxes open to get at the pinions

[sonofsam 5]

http://forum.205gtidrivers.com/index.php?s...earbox&st=0

[Henry Yorke 269 3 Cars]

My gearbox is great (though it has always hada knackered bearing in it that just rattles ). But my CTI has 164 bhp and only half a bar pressure. I did wind the boost up once on a bleed valve but started getting traction issues so I binned it as it took the drivability away from the car. Boosted 205's with over 200 bhp will always struggle to get traction down as there is such a big difference between boost bhp and off boost bhp which is when the wheelspin occurs. A diff is really the answer as you get twice as much grip theoretically

[whizzer71 0]

A diff is really the answer as you get twice as much grip theoretically

 

Still fights for grip when on boost even on a dry day with really sticky tyres ,its the torque that does it !

 

[TT205 42]

Alex

 

Have you seen this?

 

http://forum.205gtidrivers.com/index.php?s...&hl=gearing

 

 

Dave

[bales 1]

Thanks for all the answers, I have just been reading the thread that Dave mentioned above and is interesting reading.

 

As far as I can tell if you use a Td final drive in a 1.9 box it will make all the ratio's about 10% longer is that correct? I can't be bothered with the hassle really of mixing and matching numerous ratio's from different boxes so I think the way to go would be either a Td box or a Td final drive. I know graham said that 1st is shorter in a Td but tbh 1st gear is useless anyway on standard boost so with more torque its not really going to be worth bothering about.

 

In the thread above that was mentioned I notice tecknopug mentions about how it has improved the drivability a lot of his car, for comparison he is saying it is too short when it revs to 6k as that is a TT engine, well with the xu10 engine given that it runs out of puff just after 5k ish then that means that you end up going in to 3rd at about 45-50mph and you get into 5th at about 90-95mph if u want to stay on boost properly!!! thats pretty damn short geared.

 

As I said earlier I have a spare 1.9 box so is fitting a different final drive relatively straightforward?

 

Thanks

 

Alex

[whizzer71 0]

As I said earlier I have a spare 1.9 box so is fitting a different final drive relatively straightforward?

 

Its a fairly straight forward job (Depending on your experience) but I would have thought that as you fitted your own turbo conversion you should be more than ok with doing a gearbox !.

306TD boxes have 3.59 FD its 3.47 FD that you want from the 205 D make sure you dont end up with a 405 or Xantia box as these use a 4.04 diff which is of course higher than the std 1.9 Gti diff,some of the 309/405 petrols also used a 3.59 diff,I had one from an old BE1 box some time ago and that came out of an old 1.6 carbed 309.

This link may help you http://www.rallyparts.co.uk/cwp_change/ certainly helped me with the very first one I did its not 100% accurate but will help you along (Shame you dont live closer I would have willingly helped you out with it)

 

[Hilgie 16 2 Cars]

I chose a Xantia TD gearbox which has quite long gearing. On a T16 engine with 270bhp it's quite sufficient

[whizzer71 0]

I chose a Xantia TD gearbox which has quite long gearing. On a T16 engine with 270bhp it's quite sufficient

Just depends what car you have it in ,Personally I thought the ratios werent all that ,But hey If it works ....