The V8 Owners Forum -

Hi all,
Got a 1971 range rover with an sd1 v8 which has been rebuilt with a piper torquemax cam and port and polished heads, It is running twin SU's with BBZ needles and it seems to be running lean at speed (ok at idle and up to 1500 perhaps, it is actually difficult to get the car past 75mph.) Plugs come out clean with slight white deposit.

I have bought a program called winSU to reccommend me needles however I have not been sent the unlock code yet!

Just wondered whether anyone on here had any experience of a similar setup and could point me towards a suitable needle,

Cheers,
Olly

Hi Olly,

Give BAC needles a try. These have the richest top end of any needle fitted to the Rover V8 engine by the factory. The top end is subtantially richer than that of the BBZ, so it may well be what you need given your vehicle is a Range Rover, and the BAC was a 4 X 4 fitment.

Ron.

Thanks Ron,

Will give them a try, certainly a lot richer then my current ones, although identical almost at low-end, which is good as it runs fine there,

I tried using a nice little program called winSU which reccomended me BCG needles, however these are extremely rich!
Don't know if anyone else has had any experience of using this program and its accuracy?

cheers,
olly

Hi
just a couple of thoughts, are the pistons in the SUs rising correctly? ie have you got the right springs in there? Often issues that are atributed to wrong needles are actually not having the right springs in there. Secondly have you tried putting the needle on the upper indent when mounting it in the piston? Not sure this applies to all the later SUs where emisions gubbins was added but certainly on earlier versions the needle can be mounted in three positions. The middle is standard, the lower one is for hot climates/ high altitude markets and the upper one cold climate/ rift valleys etc. They give you a way of giving a "global" change of AFR over the whole range whilst still being able to set the correct idle mixture. With correct operation of the carb can be a great help in deciding which needles to try next.
Best regards
Mike