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Discussion Starter · #1 ·
Just as the title states, over the years I have used both types of gaskets with intake manifolds. The thickness with the 90 degree cut of the thermal gaskets obviously changes the port match line up vs the thin oem gasket. What is worse the increased temp. change from heatsoak transfer from cylinder head to intake manifold? Or keeping the angle of the runners to intake port as true as possible?
 

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Heat transfer from the manifold wall to the intake air is next to irrelevant under high loads aka high air flow.
The only time you ever feel effects are with heavily heat soaked manifolds are near idle revs and low loads as ignition timing will be reduced from the IAT correction. For forced induction set-ups it might therefore make sense as many ECU systems would retard ignition timing driving off from a standstill seeing high IATs causes by a sensor fitted in a hot manifold. The IAT correction is usually not load dependent.
 

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Discussion Starter · #3 ·
thank you for that Lotus. Do you think these thermal intake manifold gaskets are and were a means of making a hype part? I do remember they are popular and Hondata blessed them as a product.

The way they are cut on a 90 degree angle makes sense to match up to a intake manifold and intake port. Do you think this makes a huge difference in the back and forth direction of air flow from plenum to runnner to port back off the closed intake valve?
 

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they usually do something good in a specific situation: you got to a stop, the intake manifold heats up at idle as little air is flowing through it to cool it. You now accelerate hard, e.g. on a dyno. The heat stored in the alloy IM is transferred into the air and heats the air for a few seconds. If there is an IAT sensor in the manifold the engine may feel sluggish. As you drive though the rev range, the IM cools down and any mal effects vanish.
With an insulating gasket, these "drive off after heat soak hesitations" disappear.

In a NA K20 the IAT sensor sits in the intake piping, so it won't even be noticed by the ECU.


If found a paper where they modelled the heat transfer in an alloy intake manifold of a diesel engine. They found some 200W of power being transferred into the air during the intake stroke. Given that we flow some 200 g/second of air at WOT and an heat capacity of air 1 J/(g*K) this would heat the air by 1°C.

Some other papers found a few °C increase in IAT of the air around the IM is hot, e.g. due to radiator flow.
As you typically lose some 1.5% of power every 10°C of IAT increase, half of the theoretical value, we can expect under a steady load that these gaskets may gain us 1-2HP. But then there is the issue with the port geometry. This may very well make us lose these 1-2HP again.

But the cars sometimes feel better of the line.
So, yes, they can benefit, but I’d rather fit a thin one vs. a thick one.
 

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Discussion Starter · #5 ·
As you typically lose some 1.5% of power every 10°C of IAT increase, half of the theoretical value, we can expect under a steady load that these gaskets may gain us 1-2HP. But then there is the issue with the port geometry. This may very well make us lose these 1-2HP again.
that seems fair. I am willing to bet the more sensitive the engine there would be less desire to run a thermal thick gasket.
 

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I thought the bigger issue rather than port matching issues are injector bungs placement in reference to the back of the intake valves.

In both cases I thought the results were marginally affecting performance at wot.
 

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This was an old topic some years back on here.
I'll see if i can find the thread but several concerns were: injector placement (due to gasket thickness), poor gasket port matching, inferior brands (melting and warping), and manifold studs breaking.

Old thread here (have run reading!):

Injector placement - due to the gasket thickness, injectors are pushed away from their factory spray trajectory thus spraying the port floor. Supposedly this loses a few ponies (no ones back to back dyno'd this afaik, I may do this some day lol). A fix for this was to have the gasket shaved at around a 5 degree angle, but with a different thermal gasket material (see gasket thread for details on this).

Poor gasket port matching - a lot of copycat Hondata TG competitors don't match port the gaskets very well thus having gasket overhang. Hondata's gasket are match ported just right though.

Certain brands of gaskets freakin melt (cough blox and ebay no names).
I've experienced a Hondata gasket warping but after about 6-7yrs of use and wound up with weird idling issue due to vacuum leaks because of the warping. I've also experience manifold studs breaking, mostly on the right side manifold end thats next to the water neck. This happens with B-series folks a lot too.

Personally went back to an OE gasket and never looked back. I also run a vented hood so that's a work around for releasing heat soak.
 

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Discussion Starter · #9 ·
I have the Hondata one. They need to be shaved 5 degrees. I am going back to the oem gasket. I have a tucked radiator and the grill for the RSX will have a ton of air pooring in. half will be for the intake the other just for the IM. i was thinking of painting the underside about 6" back off the head of the IM white to reflect the block's heat and using a carbon fiber panel b/t the left side of the IM and the pulley system. This should direct more air to the IM and keep the heat of the alt, water pump, water passage, PS pump etc away some. The tucked radiator gives me 7.5" of air gap above it, that will be alot of air coming in.
 

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regarding breaking IM studs and even intake manifolds. There is a reason Honda fitted the manifold stays underneath. Without the IM is wiggled up like a giant pendulum and down at 2x the engine speed from secondary imbalance forces.
 

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Discussion Starter · #11 ·
regarding breaking IM studs and even intake manifolds. There is a reason Honda fitted the manifold stays underneath. Without the IM is wiggled up like a giant pendulum and down at 2x the engine speed from secondary imbalance forces.
are you refering to the two IM support braces that bolt to the block at the bottom? having those helps with the breaking of studs & the actual IM.
 

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Discussion Starter · #13 ·
yes, the support brackets. At least one of them should be installed, preferably the one on the TB side.
right on you are correct. when a K20a2 switches to an RBC IM the supports do not line up anymore and alot of people do not think to alter the ones they have or buy the RBC IM supports. I not sure. I am using the support bracket on my RBC.

the Euro R RBC IM support brace has the PN# (17125-RBC-J00). The K20z3 RBC support brace is PN# (17125-RRB-A00).
 

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Discussion Starter · #16 ·

here is one from M&M that says to use two oem IM's on both sides of the thermal gasket. they are saying the thermal gasket is 3mm thick.
 
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