odonnell

I'm going to be drilling and tapping a manifold for an open element sensor at some point. If someone sends some spacers I'm happy to test them.

V2Rocket

I have a manifold already drilled and tapped for such an experiment, and a 3/8 phenolic spacer machined to fit the 944 head.

I don't know if I'll ever get around to this test but if you think you might, I'll make you a deal...

odonnell

I'll buy some straight up if they're the right price.

CO951

I agree, I don't think anyone doubts that the manifold will be cooler with them, the question is will the air in the manifold actually be cooler because of it. If I were to do this test (and I'm not) I'd want to take a air temp before the manifold to see if there is an air temp change with % without the spacers.

He did see some small performance gains (I wouldn't expect more than he saw) in the test I referenced, it just doesn't explain why, which I really want to know.

Tiger03447

Michael & Spencer..let me know what you think.My intake is still off the engine and this would be a good time to add one...might be in the mix for next month or two..want to get the engine installed first. I am interested, Spencer..any reports from other buyers?

V2Rocket

Tiger - the experiment for this thread never happened.
I could do some dyno runs but I don't know how relevant they'd be, since it's pretty cold here now.

Tiger03447

Pretty cold here the last couple of days -1 this AM..Brr. even with the electric blanket..Noah must be even more cold than that..Supposed to break tomorrow with a heat wave of about 40....LOL!

odonnell

When I realistically get around to being able to test in 6 months or so, it will be 100* consistently...

Ish_944

The reason I'm interested in this is that my IAT can go up to 60 Celsius during idle.
I have a stock intake tract, too, so it sucks the air from in front of the wheel well. Temperature is measured at the (removed) AFM's position.

I do find this strange... would be glad to be able to mitigate it.

V2Rocket

That's very unusual, I logged my iat when I was running a cone filter intake and on a 40C day the iat never passed 45C even while idling for a long time.

Dougs951S

Need an intake spacer to clear my hx35 since I had to space the turbo away from the mount ~11.5 mm. would be interested in a kit without intake manifold gaskets and ideally in 5/16" thickness. btw does a strut brace clear the hood with this spacer mounted?

Tiger03447

Sounds like the only way to get the temps down in the intake tract would be to have the entire manifold duplicated in a phenolic material...that would be insulative as well as quite smooth on the runners. That might be another reason that a lot of newer engines are running plastic manifold on the intake side. But most probably for weight reduction, and less expensive to produce en mass. A thick fiber or phenolic base gasket on carbureted engines especially with a 4 barrel carb, must be run, otherwise the engine heat will percolate the fuel in the float chamber. I still think that Spencer's idea is a good one..Did you ever get it sorted out for the early cars with the fuel rail issue, Spencer?

V2Rocket

Never bothered to play with it.
The fuel rail mounting could probably be resolved with a block with two sets of holes drilled in it though.

fasteddie313

Not to be argumentative, but an interesting observation of mine is that reducing intake air temps ABSOLUTELY reduces the temp of the intake manifold..

After adding an intercooler between my turbo and the same intake, the intake is easily 100+ degrees cooler.. The harder I run it the colder it gets.. It is unnaturally cold compared to everything else in my engine bay..

It will heat soak if left idling, but take it for a good run - cold.. cold cold..

Before you could fry an egg on it, now you can put your cheek on it..

So now..
If dirastically decreasing intake air temps can dirastically decrease the intake manifold temps, it must work vise versa..

It's not a heat 1 way street, it's a heat exchange..
If air can cool the intake, then why couldn't the intake heat the air?
Well, if the air is cooling the intake, then the intake MUST be heating the air, huge amounts of cold air stripping the heat out of the intake manifold..

A difference in intake manifold temp may not heat the air enough to matter at performance level operation because their is so much more air in play than their is intake manifold, but it has to some or their is no way my air could cool my manifold if not..

Is this why things feel colder than you would think physically possible?
So much flowing air can actually strip more heat than ambient temp?

ideola

Not true.