BX 16v Auto?

Ian Fearn · Post by **Ian Fearn** » 16 Jul 2005, 21:43

I've had a question today off a citroen car club member if its possible to mate the auto gearbox to a BX16v?
Anybody any ideas?

vanny · Post by **vanny** » 16 Jul 2005, 23:14

theres no reason why not as the engines fitted with the Auto can also be fitted with the BE3 found on the 16v engine. However the auto clutch is unlikely to be upto the increased power of the 160bhp 16v box. I'm guessing Alans will have a much better idea on this!

AndersDK · Post by **AndersDK** » 17 Jul 2005, 03:07

That would be like trying to mate 2 very different worlds - even though the box is a direct bolt on.
Because :
1) the 16V engine is designed, constructed and thought to be used for enthusiastic driving at around some 4500-6000Rpm. Look at the Bhp/torque curve - its constantly raising until a sharp peak. Its worth nothing as a low Rpm puller.
2) the auto box is inherently NOT constructed for enthusiastic driving. It is much more useful in the mid-range 2500-3500Rpm in town traffic driven by an engine with a rather flat Bhp/torque curve.
No doubt it will be quite easy technically to mate the two DIY. But not much use for driving.

alan s · Post by **alan s** » 17 Jul 2005, 03:16

I have seen this question asked previously and heard of those who intended doing it but never seen any return responses saying it had been done or how well it performed.
Personally, I think it would be a dog to drive because of its lack of down low power leading to some "interesting" situations in traffic. Once wound up, I have to wonder how the tranny would cope with that sudden whoosh of power from 4500 onwards.[:0]
Drive shafts may pose a problem. I'm basing that on the CX neding about 5 different types of shafts due to different engine sizes, 4 and 5 speed transmissions, C-matic and auto, wide and normal track widths, so chances are the shafts off a 16V manual wouldn't be suitable and I don't know if lengths are compatable with 8 valve autos.
The torque converter woul be needed to replace the flywheel and we recently got caught doing an auto to manual conversion over here when it was discovered partway through the conversion that the mounting for the crank angle sensor wasn't there on the manual box and another box had to be sourced to swap the bell housing over to make it fit, turning what was a few days joib into a few weeks.
Personally, it's not a job that I would tackle and one I'd have strong doubts on it being a success if it ever was.
Alan S

citronut · Post by **citronut** » 17 Jul 2005, 03:39

wouldnt an auto box from a BX diesel do the job if they are any differant to petrol autos regards malcolm

AndersDK · Post by **AndersDK** » 17 Jul 2005, 03:47

Its not the box Malcolm. Its the BX 16V engine that is really not suited for any autobox.

vanny · Post by **vanny** » 17 Jul 2005, 04:19

the BX diesel auto box is identical to the petrol bar the obvious ratios! they both handle the same torque etc so thats not much of a help! Its been suggested on another forum that a Xantia auto box might help but as i understand it they are near impossible to get onto a BX though i cant remember why!

jeremy · Post by **jeremy** » 17 Jul 2005, 14:17

I agree with Anders and Alan - yes you probably can do it but you won't like it when you have!
Just look at the 8 valve and 16 valve gear ratios! I think you will find that the 135 MPH 16 valve pulls 20 MPh per 1000 rpm in 5th and the 8 valve nearer 23. The 16 valve is a screamer - the 8 valve a relative lugger.
As a matter of interest I'm not sure what determins the intermediate gear change points but there must be some setting in the box as a diesel will rev to about 4500 rpm and the box will change form 1-2, 2-3 and 3-4 on full acceleration somewhere around these revs. Presumably the same point for the 8 valve is higher - but it could be that a 16 valve on a diesel box would be barely faster than the diesel if it changed on the diesel points!
jeremy

citronut · Post by **citronut** » 17 Jul 2005, 14:30

i would have thought the diesel auto box was more bullet proof,as diesels do give more of a kick regards malcolm

alan s · Post by **alan s** » 17 Jul 2005, 14:52

The 16V doesn't start to bite until it hits 4500rpm and will comfortably run at 6000 rpm, so I could imagine anything that would be comfortable with a diesel plopping away at low revs would have a spasm when the 16V began getting up around the 6K or more, such as the 7200 the rev limiter kicks in at.
At lower revs, the 16V is pretty ordinary and most of us who drive them try not to let them get into the low rev range, but with an auto you may not have an option.
Alan S

jeremy · Post by **jeremy** » 17 Jul 2005, 15:26

Citronut - I've got to ask - what kick - we're not talking turbo diesel here but NA - max torque for the improved 71 BHP one is 90 lb ft, 8 valve petrol GTi is 123 lb ft.
I keep looking for some kick from the ZX 1.9D - goes nicely but its no sprinter! Mind you the wife did come back one day complaining that it kept surging ahead - and i was hopeful she'd found some hidden power but it turned out the throttle pedal was catching the mat and not returning properly!
jeremy

vanny · Post by **vanny** » 18 Jul 2005, 05:37

Jeremy, i've been there too with a 1.9d BX, and i have one question for you, how many HOURS do you find it takes to get from 80 to 90? my record (yes i was timing) was 22 minutes on a ver flat road! certainly no power there! It was such a good lugger

DoubleChevron · Post by **DoubleChevron** » 18 Jul 2005, 06:12

If you want speed with a slugomatic gearbox, a V6 Xantia is probably the only simple option. If you want an older car, no doubt a (strong) auto bolted into a CX GTi Turbo would work well (it's the opposite to the 16valve BX, stump pulling torque down low, but it's no high revving screamer).
I too agree a 16valve automatic BX would be a shocking Pig of a thing to drive... Pushbikes would probably beat you away from traffic lights...
What about a turbo deisel BX/Xantia combined with the slushbox ??
seeya,
Shane L.