Plastic intake manifold/Phenolic Intake Spacers

[SLODRIVE]

It would take about 10 minutes to make those spacers. I hope they don't cost much!

Personally, I'm suspicious of those spacers' effectiveness. I'm a believer in plastic intakes (they work great on tons of other cars), but Subaru intakes have such a small mounting flange relative to the manifold's size that I can't see how two little spacers wil keep it cooler. There's just far too much heat being radiated to the intake runners and plenum from the rest of the engine compartment.

[gijonas]

There's just far too much heat being radiated to the intake runners and plenum from the rest of the engine compartment.

Thats what i was thinking,not to mention the fact that its not only small but you dont have metal to metal contact due to the gasket.Im willing to bet the majority of heat actually comes from elsewhere.

[ThatZkid]

Maybe I'm being blasphemous here...but has anyone tried the Hondata spacers?

[kimokalihi]

They were $70 plus shipping. Kinda spendy. I will certainly find out if they work or not.

Seems like they would work to me. The gasket is so thin, it's still going to transfer a lot of heat. Besides with this spacer, there will now be 2 gaskets between the heads and the manifold.

[kimokalihi]

This guy here had pretty good results temp wise with phenolic spacers on his mazda.

http://autospeed.com/cms/A_110474/article.html

The intake ran 30 degrees F (17 degrees C) cooler at cruise and at least 50 degrees F (28 degrees C) cooler at idle;
According to my dyno plots, I gained up to 7 horsepower and 11 ft-lbs of torque over the major portion of the power curve.
My best time at the track was ~0.1 seconds quicker and ~1 mph faster.

That sounds like a pretty considerable temp difference to me.

[gijonas]

Yeah that looks good.

[SLODRIVE]

Notice that his Miata originally had METAL intake gaskets, which would have provided zero insulation to begin with. Also note that this guy has been nowhere near an actual dyno, and his two dragstrip runs were months apart, with zero mention of air density, or any other factors for that matter besides ambient temp. I personally don't think that article makes for a very strong argument...but to each their own.

That said, I am interested to see what your results are if you go this route!

[kimokalihi]

I did notice those things but I wasn't after dyno results. I was just impressed with his temperature differences even though they may have been affected by other things. The cooler the air, the less chance of detonation along with more air mass within the same volume.

Problem is, I can't record my temp results. The only thing I'll have to go by is touching the manifold to see if it feels cooler lol.

I've never run this engine before, I don't even know if it'll run! And I don't want to install the engine, run it, record temperatures and then pull the manifold and install the spacers and record temps again. It's on my engine stand right now with the manifold off already so I'm going to do it now.