Thread: 93 3.5 EFI to Carb ????

Originally Posted by Bazzle218

I am currentley driving an early 93 3.5 Auto running efi hotwire. I'm sure its possible but has anyone converted a efi back to carby and what was the results. I have searched forums but no real answers. My question given the current fuel guzzling efi system is will a well tuned edelbrock carb and manifold out perform economy wise the old efi system. Open to suggestions re carbies ect. Also vehicle is rarely off road.

Buy 300 Disco engine and stick in it.
I'm not sure a carb set up will comply with emission rule for 93 unless on 100% lpg when inspected


On your ex disco have straightened up steering and drives ok. Never found the lock nut tool for it

Cheers Tony

I doubt it.
A 14CUX Disco 3.5 should get pretty well as good fuel /air ratio as possible.
The main factor in getting better economy on my 3.9 RRC, was to get far more advance on light throttle using a Unichip.
The Australian Discos/RRCs at that time were "Rest of World" and designed to run on 87octane vs Australian 92 AFAIR and the compression ratio is 8.13:1.
So that is the route I would go.
If you insist on carbys, I understand the best carby is the Weber from a Capri V6, although these days they are like "rockinghorse proverbial"
My first port of checking for poor economy is :-

Find out what your economy is and see if that is normal. ( about 19-20l100Km around town and 15-16 on the highway for a 3.9 auto is normal)

If not normal do a diagnostic on the efi and check whether the vacuum and centrifugal advances are working.
If they are working advance the static timing by 1 degree increments and see if it pings. Some can take 11 degrees static.
Regards Philip A

An Edelbrock dual plane manifold with a Rochester Quadra-jet carb is a good set-up and eliminates that pesky electronic unreliability. If you find a need for more power at the highger rev. ranges then you can grind down the plane divider a little (or a lot) to allow the whole carb to feed both sides instead being effectively a twin carb system with the full height divider in place. You do lose bottom end performance when you start cutting down the divider. As for fuel economy, you have a two tonne car being pulled along by a 3.5 litre hard working lettle engine, really a bit undersized for the job. Think on this, if you are not fed then you won't work either.