Should I re-connect it for the winter? I live on Long Island, NY

Stupid mod, you shouldn't have done it in the first place. yes definitely redo it if it gets cold where you are.

Given snow and cold temps in the winter, It wouldn't hurt to reattach it.

Should I re-connect it for the winter? I live on Long Island, NY

But then you'd have to live with a warm throttle-body and a 0.1-degree rise in intake temperature. :wavey:

better than a frozen throttle body. :rofl:

hrmmm Ill probably just reconnect... and it was more than .1 degree... my throttle body was hot to the touch. very hot!

dew et! you live in NY...

my throttle body was hot to the touch. very hot!

Just put it back to stock. This is and has been the epic ricer mod for decades.

hrmmm Ill probably just reconnect... and it was more than .1 degree... my throttle body was hot to the touch. very hot!

No doubt. But hundreds of cubic feet of air are passing through per minute, so it would take a tremendous heat source to warm all that air to any degree. That little coolant passage can't deliver that much heat, plus the inside of the throttle body is designed to pass air, not to heat it. If, in fact, there was a significant heat transfer happening, the throttle body would NOT be hot to the touch! Which, of course would defeat the whole purpose of the throttle heat. So really, you've already proved to yourself the pointlessness of the mod. :)

It is also pointless to even bother re-attaching it.

I went through a Quebec winter, with -40F temperatures and no coolant going through my throttle body.

Car parked outside UNDER the snow, all winter.

Never had a problem, car always started on the first try.

I wouldn't worry about it.

It is also pointless to even bother re-attaching it.

I went through a Quebec winter, with -40F temperatures and no coolant going through my throttle body.

Car parked outside UNDER the snow, all winter.

Never had a problem, car always started on the first try.

I wouldn't worry about it.

Same here... well, Northern Ohio Winter. My car had this mod done when I bought it... i left it alone.

The only reason to reconnect it would be for warranty work. Mazda doesn't like when you start re-routing their cooling pipes.

I suspect it is there to maintain a more consistent temperature of the drive by wire motor. Mazda used engine coolant to maintain a consistent solenoid temperature on the old idle air control valves of previous rotaries. It couldn't hurt to keep the TB coolant hose installed, but it's not going to make a huge difference either way IMO.

I did the simple one minute one and here is a member that did the bypass and seems happy.

http://www.rx8club.com/showthread.php?t=184646

did the bypass and seems happy.


I didn't do the bypass and I'm even happier.

What kind of criterion is 'seeming happy'?

Until you put thermocouples before and after the throttlebody, or do a set of related timed runs, you are just guessing, hoping, and looking for another 1% from your butt-dyno.....

This modification accomplishes less than the 'insulating-the-frosty-pipe' one.

Don't get me started.......

It is also pointless to even bother re-attaching it.

I went through a Quebec winter, with -40F temperatures and no coolant going through my throttle body.

Car parked outside UNDER the snow, all winter.

Never had a problem, car always started on the first try.

I wouldn't worry about it.

Throttle heating isn't about startup -- obviously there's no hot coolant circulating then.

Google "throttle ice" or "carburetor ice" if you're interested.

did the bypass and seems happy.


I didn't do the bypass and I'm even happier.

What kind of criterion is 'seeming happy'?

Until you put thermocouples before and after the throttlebody, or do a set of related timed runs, you are just guessing, hoping, and looking for another 1% from your butt-dyno.....

This modification accomplishes less than the 'insulating-the-frosty-pipe' one.

Don't get me started.......

As far as performance benefits, I honestly can't tell you as I havent driven my RX-8 enough to give you a difference in hard numbers. What I could tell you is that I ran my RX-8 against another stock one at the track. After we pulled off (10-15 minutes), my TB with the mod is cool enough to touch while his was so hot that I couldn't even touch it. Since fuel is set before the TB, god knows if it works or not. I do have a datalogger to test these things, but I just haven't had the time or the real desire to waste gas to test things like that. I guess my point is if you like a cool TB, do the mod. If not, I am sure you don't lose much with it

Lose much? This mod does nothing to increase horsepower. It really does nothing for the car at all, except to move coolant so it doesn't go through the TB. I suspect that arghx7 is on the right track that it does something, but so negligible to our understanding that people think it is a good idea. If you really want to know why people think it is a good mod or even a worthwhile one there is a thread about, but still nothing definitive. Honestly there air doesn't sit in there long enough to get hot, you gain nothing except a cool TB and some extra hoses.

That being said I've done this mod, but honestly I have no idea why. I guess to give me something to do for 5 minutes. Maybe it's because when I drive to a friend's house to use their garage I like to be able to take my intake off without burning myself if need be. I have no idea why.

http://www.rx8club.com/attachment.php?attachmentid=146996&stc=1&d=1255795076

You can see in this diagram of the FC3S idle air control valve why engine coolant is supplied.

Epic Win!

Seeing that, I think I'll switch it back.

http://www.rx8club.com/attachment.php?attachmentid=146996&stc=1&d=1255795076

You can see in this diagram of the FC3S idle air control valve why engine coolant is supplied.

While I am not going to argue the benefits/drawbacks of bypassing, the RX8's idle air is ECU controlled with the throttle blade angle, not a separate solenoid.

Now, on a solenoid actuated system I can see why that would be important.

RX-8's system is different, coolant is circulating all the time, that's why I am not sold on plugging the coolant passage with a screw