RCR S2

Background:

I just installed the Hondata intake insulator gasket last week. The temps did reduce some what and I thought no more antifreeze into the throttle body.

We'll one of the small coolant hoses developed a leak and anti-freeze was spraying out of it. This is the hose on the intake manifold by the throttle cable.

I thought the Hondata insulator would prevent coolant from entering the throttle body. We'll after taking a look at it I discovered that even with the Hondata insulator, coolant still get's into the throttle body and manifold.

What the insulator does is block the forward flowing coolant passage into the throttle body. But if you reconnected all the hoses back, you'll find that the coolant actually flows into the intake manifold and throttle body through the coolant return hose located by the throttle cable.

Even though the coolant doesn't "flow", you still have coolant in the parts and it will actually heat up the intake manifold and throttle body.

Solution

What I did was add a bypass hose from the coolant return line to the bleed nipple. This way coolant doesn't enter the throttle body and manifold. You can also just use a plug on the return line, but I couldn't find a plug that fits.

After the mods, I noticed anywhere from 5-10 degrees lower intake temps via ODB-II. The temps also drop faster when the car starts to move because it doesn't have to cool down the coolant inside the manifold and throttle body.

I used a 5/16" fuel line to bypass the throttle body as the standard 3/8" coolant hoses were too big.

Results

Rough numbers via ODB-II monitor (coolant at about 183F and outside air about 75F while driving with light throttle):

Without Hondata Insulator: Avg temps were about 126F
With Hondata Insulator: Avg temps were about 112F
With Hondata Insulator and coolant by pass: Avg temp were about 105F


Conclusion

This mod is relatively simple to do and allows the Hondata Insulator to do what it was intended to do. Cooler intake temps and quicker temperature drop is a good thing. And when winter comes, you can reconnect the hoses to the throttle body to warm it up a bit.

Sebringer

Interesting. Could you post a pic helping to identify which hose you are speaking of? Thanks much

JustJustin

Can I stop by and see it some time, or have you stop over? We might have met at Speedquest, and I live in Grayslake.

-Justin

GaryRudolph

Did you get the right hondata insulator? I thought the street one still allowed cooling flow, and the race one did not.

Or are you saying even with the race one you had to do this?

I'm trying to see what downside there is to not having coolant through the intake (like you're doing).

Asura

Street and Race versions? I was only aware of there being one gasket for the S2000.

RCR S2

I got it from the group buy. It does block the coolant flow to the Throttle body. I matched it up with my stock one.

It's suppose to block the flow into it, but you also need to plug the coolant exit tube otherwise, the coolant back flows into the intake/TB due to the pressure.

RCR S2

I will be at Great Lakes Dragaway tomorrow night. If you go, I will show you there.

I'll also post up a pic of the tube tonight.

Gernby

There are 2 versions of the gasket for some motors, but only 1 version for the F20C. Some motors can have ALL coolant passages through the IM blocked, but the F20C cannot.

wortham

very intelligent, concise, and informative write up with numbers to back it up. kudos for a good, education read, bro.

Chiung

Nice write up and testing.

Check the 3rd and 17th pictures in this thread to see the coolant plugs. The 3rd pic shows the plug (cap) to the right of the TB. The 17th pic shows the other plug to the right of the valve cover.

https://www.s2ki.com/forums/index.php?showt...71067&hl=bypass