Why Is My Intake Manifold Heated?

[Medium Dave]

Im sure there must be a reasonable explanation, but why is it that my stock manifold has a water feed. My old alfa had a heated intake for fuel economy, but we go to lengths to cool the intake charge then have it heated by the plenum?

[salad]

ive wondered this aswell, would be interested to find out

[Craved]

anti freeze properties

so the TB isn't frozen open or shut

[r33_racer]

below zero climates could seriously stuff with your engine and its mechanical workings....for eg if you lived in japan and parked your skyline outside during winter Same as the heater/cooler on the oil filter.

[rob82]

Emissions. Everything is about emissions. Fuel vaporises easier when the manifold is hot. Thats why you have cold enrichment - to get the car to drive nice when cold becasue the atomisation/vaporistation is shite.

[ish]

Rob's right ! its mainly for start up ...

on Rb30's we bleed it and blocked it off for some interesting results

[RANDY]

What kind of interesting results?

[Medium Dave]

I thought it might be for emissions, but for a cold start up I thought the thermostat restricted water flowing untill the engine was warm anyway?

So could I use a brass T' piece to divert the flow from the head?...

-Might have to try that in summer, its still too cold in Tas (sympathy please )

Edited August 2, 2006 by Medium Dave

[kjb_r33]

Rob is on the money. When you have a shower of a morning, the steam condenses on the mirror. If the manifold is cold the same thing happens with fuel, it condenses on the inlet manifold, giving you a lean mixture which isnt conducive to smooth running with a cold engine.

[ish]

no do not divert the water away from the head.

the head must always flow water.

You block each end of the inlet/outlet jacket to the plenum so its bypassed. This is easy on An RB30

I cant comment on the twincam stuff.

note! you will Have ruff start up if you live in cold areas....

[Medium Dave]

Ah, yeah, by head I mean inlet manifold

Hmm, interesting stuff tho, but considering I live in tas.... I might leave it alone, thanks guys for the info

[someonestolecc]

You block each end of the inlet/outlet jacket to the plenum so its bypassed. This is easy on An RB30

I cant comment on the twincam stuff.

note! you will Have ruff start up if you live in cold areas....

That's what you do and what the negative is... what is the positive??

[Craved]

the water feed to teh turbo comes from the plenum .

if you are talking about the line that runs next to the injectors??? it comes out of the rear of the plenum around the back of the head and to the turbo... i wouldnt be blocking this off