Motordyne iso thermal plenum spacer
#19
there seems to be some confusion (or misrepresentation) about Iso-Thermal...
First off to clear some confusion - the plenum spacer is what it is it's an aluminum spacer that goes between the upper and lower collector (Iso-Thermal has nothing to do with this). 5/16" and 1/2" options.
The Iso Thermal Kit is an additional system that can be used with the spacer (or not). The kit consists of an Aramid gasket (thermal barrier) that goes between the intake manifold and lower collector (bottom part of plenum) - this helps prevent excessive engine heat from entering the plenum. In addition to the Aramid gasket is a coolant control valve that prevents coolant flow to throttle body. Coolant is obviously hot, and OEM flows through TB to prevent throttle plate from freezing (in very cold climate). Bypassing (or shutting off this flow) keeps the TB cooler (in theory keeping air cooler entering plenum and into combustion chamber).
There are two types of coolant control valves; manual (a thumb switch run inline in the hose under intake tube *older version is a screw to open/close) or a copper unit (thin spacer) that installs between the throttle body and plenum neck opening. They both do the same thing (in a different way) - they help keep the plenum cooler... the copper version is more of an automatic coolant control, the valve is a manual version - the only reason to use copper is in extremely cold weather (so you arent constantly opening and closing the manual valve). If you live in mild climate (like So Cal) you can use the manual valve and leave it shut most of the time (I open mine occasionally only to help keep the TB clean, I've noticed when it's shut for long periods carbon seems to build up quicker).
I realize this isnt anything that hasnt been said before (and can be found in numerous areas on a search) - but it seems this thread has a bit of confusion so I figured I'd try to clear the air.
First off to clear some confusion - the plenum spacer is what it is it's an aluminum spacer that goes between the upper and lower collector (Iso-Thermal has nothing to do with this). 5/16" and 1/2" options.
The Iso Thermal Kit is an additional system that can be used with the spacer (or not). The kit consists of an Aramid gasket (thermal barrier) that goes between the intake manifold and lower collector (bottom part of plenum) - this helps prevent excessive engine heat from entering the plenum. In addition to the Aramid gasket is a coolant control valve that prevents coolant flow to throttle body. Coolant is obviously hot, and OEM flows through TB to prevent throttle plate from freezing (in very cold climate). Bypassing (or shutting off this flow) keeps the TB cooler (in theory keeping air cooler entering plenum and into combustion chamber).
There are two types of coolant control valves; manual (a thumb switch run inline in the hose under intake tube *older version is a screw to open/close) or a copper unit (thin spacer) that installs between the throttle body and plenum neck opening. They both do the same thing (in a different way) - they help keep the plenum cooler... the copper version is more of an automatic coolant control, the valve is a manual version - the only reason to use copper is in extremely cold weather (so you arent constantly opening and closing the manual valve). If you live in mild climate (like So Cal) you can use the manual valve and leave it shut most of the time (I open mine occasionally only to help keep the TB clean, I've noticed when it's shut for long periods carbon seems to build up quicker).
I realize this isnt anything that hasnt been said before (and can be found in numerous areas on a search) - but it seems this thread has a bit of confusion so I figured I'd try to clear the air.
#25
#27
There has to be some other problem then. I installed mine, and saw no change at all in my gas mileage. Come to think of it, I might've even increased it by a few fractions.
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thechitoguy
G35 Sedan V35 2003-06
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10-01-2015 05:25 PM