Having bypassed the throttle body months ago, and having talked to someone at the last meet about the IAC valve bypass, I decided to bypass the valve on the intake manifold. I determined that there was no temp sensor on the valve where the coolant went prior to this move.

The car seems to run fine with no idle problems, and after long drives in 70s temp, the intake manifold is merely warm to the touch, something that had never been the case before. I think the 'coolant' really was heating the intake manifold quite a bit. The exhaust pipe remains very clean, as a possible indication of how the car is running.

I had also wrapped the intake tube with insulation and have the Spoon type cai.

 

Doc, you got any pics?

 

Ahh prolene

a very old trick from the Bseries days

Working well?

 

[QUOTE]Originally posted by tze
[B]Ahh prolene

a very old trick from the Bseries days

 

Please do take pics. This is and was a common mod to help keep the manifold and intake charge temps cool. On most cars it works fine, on some it can actually bypass the idle air control valve (IAC) which can wreak havoc. The trick is to do it right, it sounds like you have.

Hondata makes an insulator that replaces the intake manifold gasket. I haven't seen numbers on the S2000 yet (I don't think it's released) but gaskets like these can keep manifold temps cooler by 10 degrees or more. All this translates into a lower intake charge temp and more power.

 

I would not recommend this mod for the winter/fall months. I tried this on my prelude, the car idle like crap in the morning, almost to a point in which it stalls.

 

The key is that you can typically not bypass the sensor, but keep coolant through the sensor and isolate the sensor from the manifold (usually by a phenolic spacer or such). I can't comment on the S2k, but I know this was a problem with the Prelude's H22.

 

I remember this trick from the ol' days. As I recall, the idea for the collant in the intake area is to prevent freezing in cold weather. But here in SoCal that's not really an issue. 4igs2000, how cold was it when your prelude had problems with this mod? Did it only have problems when you first started it? Did it run better?

 

A few of us will be testing the new Hondata gasket out. We'll do some temp testing as well as instrumented acceleration. I may even try and get a dyno run in.

On the topic of the bypass, last time I was at Hondata I showed Doug my TB coolant bypass and he recommended that I bypass the IAC line as well. I raised the same concerns as you all and he told me it wouldn't be an issue, especially here in SoCal. I passed the same advice on to the good doctor (I haven't made the change yet). Good to hear that it works.

UL

 

On the H22, ambient temps below I believe 50