Something happened in 1991

[Brian King]

A Citroen club member (an engineer) drove my 1990 BX GTi 4x4 the other day (very gently) and said he didn't think it had as much power as he remembered on his old GTi. I had found that if you put you foot literally to the floor, it performed better. I looked up the performance figures in the BOL (Haynes), and it says in there something that might explain what he said. Apparently up to 1991 the GTi had a D6A engine producing 125bhp @ 5,500 and 129 lbs/ft of torque @ 4500. From 1991 onwards the GTi had a D6D engine producing about the same bhp and torque but, astonishingly, the torque came in at much, much lower revs - 2,750. Could this explain what he said? Maybe his GTi was a later one and he was expecting a kick in the back at lower revs, which just did not happen with mine. It seems that you have to drive the earlier GTi like a 16v, but the later one like a turbo diesel. Has anyone else noticed this difference?

[Kitch]

I imagine it was probably de-tuned slightly for economy/emissions issues. The 16v's underwent a similar overhaul, with the addition of a knock sensor and 3 row ECU, so many later 1991 valvers aren't quite as raw asw the 2 row cars (thankfully my 1991 reg valver was in fact made in 1990...so 2 row spec!) Afterwards the valver was fitted with a cat and ruined, but I don't think the 4x4 GTi ever had a cat AFAIK?

I know the 205 GTi was de-tuned from 130bhp to 122bhp around the same era, possilby again due to a catalyst.

[jeremy]

The figure quoted is for maximum torque. I think you'll find that the torque curve is fairly flat and if after the modifications the shape was altered slightly overall it was very similar - and so may be a couple of lb ft different at various places - so if on the old engine it was 129 lb ft at 4500 it could be say 120 lb ft at 2750.

I remember seeing the torque curve for a 4.2 Jaguar fuel injected engine - the early ones actually quoted maximum torque at 1500 rpm - the later ones at rather higher revs. When you looked at the curve it was virtually flat from 1500 to 4000 rpm - so later engines only had to produce a few LB FT more to make the engine sound completely different on paper.

Your problems sound like a tuning issue - I'd start by looking at the easy bits like the vent pipes first and working your way through all of it patiently and one aspect at a time and eventually you'll be rewarded by a smooth powerful engine with a wide torque band.

Many years ago I had a Triumph Stag - I rebuilt the engine and all seemed fine but I didn't feel it went as well as a 3 litre V8 should. I eventually found a rotten vent pipe, changed it and suddenly I had a car that would pull overdrive from about 20 MPH and on an open road went so well that if I needed to change out of top to overtake I was far too close to oncoming traffic!

[Philip Chidlow]

I've driven GTis from '87, '88, '89, '90, 91 and '92 and I must say the quickest (un-chipped) I ever drove was a white '89 (F***RLO). I haven't noticed much difference TBH. One thing though, about my current GTi, which is a 1991 auto, is the off-the-mark and kickdown acceleration is pretty damn good.

I would imagine the drag of the transmission on a 4x4 would be the biggest factor in affecting the impression of sluggish behaviour...

[Jaba]

I think that 2750 is a BOL misprint. Should be 4750. There is no real difference on the road between the GTi models, unless there is a cat fitted, but this would then not be a D6x engine.

[MULLEY]

The 4x4 is slower than the 2wd version & consumes petrol quite a bit more as well. That was the reason why i didnt end up buying a 4x4, i didnt know about all the other issues associated with it, thank god i didnt buy one, phew....

[Brian King]

Yes but you should see it accellerate over wet grass !

[fourwheelsteer]

I think that 2750 is a BOL misprint. Should be 4750. There is no real difference on the road between the GTi models, unless there is a cat fitted, but this would then not be a D6x engine.

Sadly the BOL is far from infallible on such technical info. If you believed Haynes you'd think the 1.6 petrol had more torque than the carbed 1.9 petrol (unless I've made a BIG mistake).

[MULLEY]

Brian, i try to keep on the black stuff myself