3.9 plenum on a 3.5?

jeepstertim · Post by **jeepstertim** » Mon Jan 05, 2009 7:14 pm

Is there any benefit from fitting a 3.9 plenum on a 3.5 engine, is there any difference at all?

Lehto · Post by **Lehto** » Mon Jan 05, 2009 7:29 pm

No difference. Only difference is that some of the 3.9L plenums say "3.9" on it.

Post by **Coops** » Mon Jan 05, 2009 7:38 pm

depending which 3.5 you have,
as the 3.9 is hot wire efi which uses a stepper motor on the plenum to assist idle,
the 3.5 has an overun valve i think in its place (flapper efi)

jeepstertim · Post by **jeepstertim** » Mon Jan 05, 2009 10:26 pm

Both 3.5 and 3.9 have steppers.

Post by **Coops** » Mon Jan 05, 2009 10:40 pm

no benefit at all then mate

ChrisJC · Post by **ChrisJC** » Tue Jan 06, 2009 8:18 am

jeepstertim wrote:Both 3.5 and 3.9 have steppers.

Both 3.5 & 3.9 hotwire have steppers, 3.5 flapper doesn't.

3.5 flapper also came on SD1 and Range Rover, and they had a different arrangement for overrun fuel cutoff - the SD1 had a valve on the rear of the plenum, the Range Rover had a core-plug in the hole and did it electronically. (In fact, I'm not really sure what the valve on the SD1 version actually did).

Chris.

kokkolanpoika · Post by **kokkolanpoika** » Wed Jan 07, 2009 7:48 am

+3,5flapper has got cold start injecktor..