Hypothetical 5th gear swap - BE3 Vs BE4 significant differences?

[MattBLancs]

Short version, 406 coupe, 2.0 EW10 petrol. 5 speed BE4 manual gearbox.

Currently 70 mph is 3,400rpm in 5th and although allows for acceleration without changing down, it's always struck me as the engine being so "busy" takes the edge off a nice GT type ambience the Coupe does so well.

Have a cheap ML6 gearbox (six speed, from 307 HDi) that does bolt up to EW10 block but has questions I need to suss out before fitting - mostly the ML6 input shaft diameter is bigger, larger splined clutch required (would be a DMF too in original home, so unsprung clutches available that aren't any use to me)


So a quicker / interim solution to consider:

Can I swap just the fifth gear from a diesel in place of the current 5th ratio? Which leads to my main question:

Are 5th gear sets from BE3 and later BE4 interchangeable?

I've had a quick look and seen mention of machining required swapping like this BE3 to BE3!?! Which was a surprise.

[MattBLancs]

https://bxclub.co.uk/forum/viewtopic.php?p=259057

viewtopic.php?t=71998

viewtopic.php?t=56300

[MattBLancs]

205 driver's thread suggests BE4 into BE3 not straight forward:

https://www.205gtidrivers.com/forums/to ... 16-to-be4/

[CitroJim]

Following with interest Matt

[MattBLancs]

Following with interest Matt

Thanks Jim,

https://eastment.net/BE3%20Gearbox%20Strip.htm
This site is very useful, did I read in passing somewhere that it's yours? I must have read that very page maybe a decade ago, bookmarked it but since then lost the bookmark! Stumbled across it again last week!


What's triggered this query is an eBay cheap C15 gearbox local to me. It's ancient and quite rusty (particularly the 5th gear end cover) but if I could get it cheap enough then - so long as the bits fit!! It could be my "longer legs" sorted fairly easily.


Longer gear swaps on the 207 GTi, BE4 gearbox seemingly common:
https://www.etuners.gr/peugeot-207-rcgt ... ion-guide/

Recommends:

44-35 – PSA part code 2344.E2 (about 10% longer than stock)
47-35 – PSA part code 2344.F2 (about 15% longer than stock)
50-33 – PSA part code 2344.F5 (longest of the lot, comes from HDI gearboxes)

A quick search on the HDi 50-33 gearset part number, this is cheapest spotted so far:
https://www.wtc.co.uk/PEB68388T.html
£117 once VAT added.
Ah, by chance fairly local - Warrington.

[MattBLancs]

Interesting update, I have a picture of the 5th gearset in my previous coupe (also a EW10J4 engined manual gearbox car) and it is stamped with the ratio:

43-37 = that's even shorter than the ratios above at 0.86

That ties in with some calcs I did a good while ago (back when Service Box was free ) and supports that info and so final drive ratio of 4.16.

Currently 70mph = 3410 rpm
Swapping to the 50-33 in this gearbox therefore translates to
70mph = 2617 rpm (23% drop)

[CitroJim]

Following with interest Matt

Thanks Jim,

https://eastment.net/BE3%20Gearbox%20Strip.htm
This site is very useful, did I read in passing somewhere that it's yours? I must have read that very page maybe a decade ago, bookmarked it but since then lost the bookmark! Stumbled across it again last week!

Yes, that's me Matt Hence my interest in what you are doing as I have a particular interest in gearboxes...

That website was from the days when I was a lot more active with the spanners and before I was seduced into the world of running and cycling!