Fitting Twin SU's to a 3.9

Alek · Post by **Alek** » Tue Jul 03, 2007 5:58 pm

Hi

I have a hotwire 3.9. I have decided that for the marine application into which it'll go I want to fit twin SU's. Having recently purchased a manifold and SU's believed to have originated from a SD1, what alterations would i have to make to the carbs so I can get the most out of them in this application.

Thanks in advance

The Original Tom · Post by **The Original Tom** » Tue Jul 03, 2007 7:10 pm

You'll more than likely need smaller needles to allow greater fuelling.
Other than that I can't see it needing anything. You may even just be able to get away with ritchening the mixture on the SU's.

No idea what needles you're after though...

Why not fit something... better? I run SU's but then I also use gas so it makes no difference to me. You could get better performance from a holley or edelbrock or weber.

ChrisJC · Post by **ChrisJC** » Wed Jul 04, 2007 7:02 am

You might have to remove one of the core plugs from behind the water pump. The SU manifold needs both water connections, but the EFi only uses one.

I think! - Worth checking anyway.

Chris.

badger · Post by **badger** » Thu Jul 05, 2007 3:07 pm

Needles you want are BAC, use with an airbox and std filters though, they're a bit lean with K&N's.