The V8 Owners Forum -

Will my hotwire 3.9 plenum be up to the task of feeding my rebuilt/modified 4.6, or would it be beneficial for me to bore it out.. Bare in mind that this is for a defender 110 not a light sports-car..

Come on guys. Surely its an easy one for guys of your calibre...

[quote="need4speed"]Will my hotwire 3.9 plenum be up to the task of feeding my rebuilt/modified 4.6, or would it be beneficial for me to bore it out.. Bare in mind that this is for a defender 110 not a light sports-car..[/quot

Presumably you have modified the engine to optimise torque in which case the 3.9 plenum should be fine for your purposes.

Kevin.

Thanks for replying Kevin. Yes my engine is currently using standard later-casting heads, skimmed to up the compression a little, and using a real-steel stump-puller cam. I'll also be using MS and EDIS.
Cheers
Phil

Big plenum is required for high revving large capacity engine - on a 4x4 its less of an issue, as you are maximising for torque in the mid range typically.

Thanks guys. Looks like i can use the one i have after all.

Given that you are running megasquirt, all you need to do is compare your MAP pressure at wide open throttle @ max RPM with the pressure you record with the engine switched off - they should be close to one another ideally (~97kpa) - otherwise known as the barometric reading on MS.