6 speed box

[FarmerPug]

So my cars now back on its home turf, the motorway doing 80 miles a day, 5 days a week so fuel economy is an important issue ive seen it go up about 100 miles a tank already on the first week, and i expect a bit more 50mpg is the target, but i was thinking would a 6 speed box not mean the car revs less at 70mph and therefore use less fuel. Was it ever an option on the 406, does peugeot even have a 6 speed box i know theres one on the citroen dispatch. Its only an idea i dont intend to change it any time soon but in theory would it work, would it make the car quicker/slower? and would fuel economy go up?

[trem1]

dont think it was an option on the 406 but peugeot definitely fit one now my 407 hdi has a 6 speed manual gearbox

[FarmerPug]

yip, its in the dispatch i remember which i think has the same engine as the 407, but isnt the 2litre hdi the same in the 406 and 407 bar a 16v head and probably some electricals, would it be possible to put in a 407 gearbox

[omega]

theres a 6 speed in the gti6 but i would check what ratios/final drive it has so you make sure you are better off
i dont know if it fits though.

[steve_earwig]

There is thought the 407 HDi 'box will fit but... Hmm, what we really need is some brave soul

[Doggy]

My thoughts exactly. Probably a good idea to get two, in case of unforseen snags.

Then when you've got it all up & running, published the how-to and quantified the benefits, I could make you an offer for the other one.

[HimBigChief]

I've been fancying a 6 speed for a while now and have been keeping my eyes open for a cheap 407 box, but there's hardly any around.

[no2lurch]

i thought the potential problem with fitting a 6 speed box is the ratios for the other gears will be different. if you got an extra gear then surely the ratio for 1st at least would be lower and ina deisel, this woiuld make it pretty useless cos you'd have to change out of it earlier on pull off, and also, would the torque of the engine be compatible with the new box - i mean would changing gears become alot more frequent to get up hills etc? of course, i might be wrong tho.

[Welly]

6-speed manuals tend to behave quite sporty in gears 1 to 5 and then in 6th it's a cruiser with low revs and yes Diesel ratios are way different to Petrols because a diesel has a max revs of around 5000.

I think the HDi's 5 speed box is nicely chosen and cruising at 60mph will show 1900 rpm which is very low really. 80mph is about 2700 ish?

[steve_earwig]

There was a brief investigation over on the coupe club here http://www.peugeot406coupe.com/phpBB3/v ... lit=+final

The bottom line seems to be the gears are closer together but top is hardly any higher than top in the 5 speed. It'd probably be easier to fit bigger tyres

don't make me edit this again!

[mjb]

Diesel gears are a lot longer than petrol ones. If you slap a 6 speed petrol box into a diesel then you'll still only have 5 gears because 1st will be of no use at all. You'd probably be revving the nuts off the engine doing 70 in top gear too - my V6 does about 4200rpm at 100mph in top whereas my TDI is probably doing around 2500rpm doing that speed in 6th (not that it can go over 70mph without entering limp-home mode )

[FarmerPug]

Whats the story with the 2.0 hdi in the 406 was it carried over into other cars, or has it been replaced by the 1.6hdi 110? Could the 2.0 hdi in a 407 be put into a 406 if there was no such curse as the electrics to worry about, that would give the 406 140bhp i think?

[Busman]

Surely its not the number of gears you have but the ratio of top gear that matters for motorway cruising? I drive lorries with up to 32 gears but they only do 56 mph at 1215 rpm.

[StevieboyTD]

theres a 6 speed in the gti6 but i would check what ratios/final drive it has so you make sure you are better off
i dont know if it fits though.

The gti6 box fits (same block), but the ratios are totally wrong for a derv.

[steve_earwig]

Surely its not the number of gears you have but the ratio of top gear that matters for motorway cruising? I drive lorries with up to 32 gears but they only do 56 mph at 1215 rpm.

Try getting there with just 5 gears...

Whats the story with the 2.0 hdi in the 406 was it carried over into other cars, or has it been replaced by the 1.6hdi 110? Could the 2.0 hdi in a 407 be put into a 406 if there was no such curse as the electrics to worry about, that would give the 406 140bhp i think?

Well yes, but the electrics is a major problem.

What you really need is an...