tomcat

This thread is a spin off from the minimum air vent thread. Others have found 150F when ambient air was 80F. This reduces air density and HP by 12%! Under hatch temps depend on performance of engine compartment vents. If you don't measure you don't know.

Anybody that can check this please let us know what you find. To be meaningful you have to measure ambient temp at the time of the test.

Thanks,

Tom

Dave M

I guess you are referring to the Manifold Air Temp reading? From my scans, it looks like that temp is usually about 20-30 degrees higher than the outside air. My MAT seems to run 120 or less. I've never seen temps as high as 150.

Raylar

Over the years as we have tested in boats on the 496, we have seen Intake air temps as high as 150 degrees. The reason is the intake manifold is the only piece of big aluminum on the engine. the heat of the engine tends to radiate up into the stock manifold and stay there, irregardless of outside ambient air temps. This is why our new intake manifold for the 496 is a dual air gap manifold we call the "coolgap". It tends to run with IAt's at about 90 degrees even in the most severe Havasu temperatures over 100 degrees. this 40-50 degree difference in IAT is one of the reasons our kits make such good power on 496's

Ray @ Raylar

tomcat

Dave M: So you are seeing ~30F temp rise. Sounds reasonable to me. That would cause about a 5% loss of air density and HP

Ray: Are you saying that your MAT is less than ambient? That would be quite a trick if you are drawing from the engine compartment where radiated heat from the engine always adds to ambient air temp.

You got an intercooler hidden inside that intake?

Nordicflame

iTrader: (4)

This seems to be the most likely scenario for the temp rise
From the Diacom readings I have it seems the single engine setups run a 20-30 degree delta and the twin applications such as mine run a +55-60 degree (more heat generation + less air space + insufficient outside air flow (in my case) = high intake temps)

Cool air to the intake will help "any" intake and I'm sure the cool gap works excellent but I have to agree with Tom here on cooling below ambient.
OK Ray, where's the IC

Dave

Raylar

Damn, left out part of the sentence! What I meant to type was "even in severe Havasu temperatures of over 100 degrees the intake air temp stays below 120 degrees"
Sorry for the flub Tom you are right, not going to see intake temps below ambient in any motor without a special cooler or alcohol in the air.

Ray @ Raylar

Vindicator240

I'm new on this can somebody tell me where the iat is on the 496? Is it the 2 wire sensor on the back side of the intake?