Which needles for SU carbs on a Rover 3.9 ?

dogdog1 · Post by **dogdog1** » Sun Jan 22, 2012 7:36 pm

Hi , Anybody know which needles would work best on a Rover 3.9 fitted with SU HIF6 carbs ? Hope someone out there can help , thanks .[/b]

RoverP6B · Post by **RoverP6B** » Sun Jan 22, 2012 8:50 pm

It depends on a number of factors.

What type and size of air filters are you using and where are they fitted,..inside an air box, on the adapters or on the elbows?

Does it have the factory camshaft?

The cylinder heads are as they left the factory?

Ron.

dogdog1 · Post by **dogdog1** » Mon Jan 23, 2012 10:53 pm

Hi , it's all standard , will probably have k&n's on the carbs ?

kiwicar · Post by **kiwicar** » Tue Jan 24, 2012 11:49 am

Hi
Putting K&N cone filters on the carbs using the existing "stubs" from the normal inlet set up (ie what is left when you have removed the existing plumbing and filters) reduces power even when you have rejetted. the standard set up with paper filter is much better.
There are two reasons for this,
1 the stubs end directly over the exhaust manifolds so you end up feeding the engie with hot air
2 The remaining stub has no flair or radius at its end, this flows far worse than the tube and airbox.
Best regards
Mike

dogdog1 · Post by **dogdog1** » Tue Jan 24, 2012 5:20 pm

Thanks Mike , I'd heard the original set up with a cold air feed from the front was pretty good , but the amount of space under the bonnet of the mk1 escort it's going into will probably be the final decider ! Regards , Gerry .

badger · Post by **badger** » Sun Feb 05, 2012 6:34 pm

If you can stick with paper element filters, try BAC needles as a starting point.