Dual Intake

[trebuchet03]

Originally Posted by apgrok1

Ok we know all of the things that can go wrong, but we still don't know why it is there. I know that GM Quad 4's had cold start emmision problems, I am assuming this could also apply to the volvo's. The hot air intake would help emmisions in that case.

? See a few posts up....

The air flap mechanism in the volvo airbox works to maintain a minimum 70f intake temp in order to make the AMM readings more accurate.

[RH77]

Originally Posted by trebuchet03

? See a few posts up....

Not sure what the question is

I owned a car with that miserable engine ('90 Beretta GTZ). The biggest emission problem was the coolant going out the tailpipe (head gasket issues).

The engine had great potential: a DOHC, 16V, high-compression, lightweight domestic engine that cranked out 180 hp from 2.3L. 5-Speed -- fun car. 75K miles it started acting funny. White vapor from the tailpipe and chocolate brown coolant. Cold starts sounded like the cylinders rings were grinding for the first few seconds. This is when I gave up and bought my first Civic.

RH77

[trebuchet03]

Originally Posted by RH77

Not sure what the question is
RH77

Sorry for the random "?" -- apgrok asked why it was there - but tjts1 had already given a pretty thorough explanation as to the way (not trying to be an ass - just keeping info moving)

[RH77]

Originally Posted by trebuchet03

Sorry for the random "?" -- apgrok asked why it was there - but tjts1 had already given a pretty thorough explanation as to the way (not trying to be an ass - just keeping info moving)

Just bustin' chops, as is my duty.

RH77

[apgrok1]

What I meant was that the hot air device was there for emmisions, not just to heat the engine sooner, although the two go hand in hand.

BTW, I also owned a 2.3L Quad 4 and also replaced a head gasket.

[Chris D.]

ok, I've bumped this thread in hopes of seeing
someone running a retrofitted setup on their ride..

So has anyone gotten fiesty and tinkered with this?
the selectable HAI/CAI setup is going to be my next mod..

[beatr911]

Have not done it but have some info.

Many old carbureted (and early EFI ) vehicles have a vacuum acutated heated intake that regulates temp at about 100*F. These have a bimetallic strip valve mounted on the clean side of the air cleaner. There is a vacuum diaphram controlled by the strip that regulates hot air from the exhaust manifold and cooler air from outside. The bimetallic strip bends at a certain temp and bleeds vacuum air to the diaphram thereby regulating the intake air temp. These are really simple devices and in my experince very reliable too. Sorry, don't have a diagram available.

The beauty of this is that at low vacuum (wide open throttle) the vacuum is not enough to pull the diaphram to feed warm air, so full cold air is fed when most needed for power. When vacuum is restored at partial throttle it's back to 100*F air. Best of all, the exposed versions of the bi-metallic strips are actually tuneable so you can play with the regulated intake temp that suits your engine, within a certain range of course.

The two vehicles I had that had this were: '72 Datsun 510, '95 Dodge Caravan, but they were also widespread on other vehicles from the early 70's to late 80's. If you see a vacuum diaphram on the air snorkel of a suspect vehicle, you've found one of these systems.