Just installed MREV2 with 5/16 iso copper spacer in my 06 revup coupe. I'm curious if anyone else with isothermal mods has measured how warm their TB gets after driving or just idling in cold weather. I have the motordyne copper TB isolator in place and my TB temps are always the same as the upper plenum. This morning with ambient at 10F and a 15 minute interstate drive, I measured 30F on the TB and upper plenum. That concerns me a bit as I would think it would be hotter than that but I don't have the technical background to know for sure. My copper isolator is installed correctly with isothermal gasket facing plenum, bare copper facing new nissan gasket, and nissan gasket facing TB. I can get my finger on the coolant line that's on the front side of the TB and it is hot. Unfortunately I can't reach the backside line because it's so tight back there. No visible leaks and the lines don't appear to be kinked.

If you've installed motordyne's isothermal gasket under the lower plenum, I'd really appreciate knowing how hot your TB gets in cold weather. Even if you don't have the copper TB isolator, I'd still like to know what other people are seeing.

 

How did you measure your temps? I'd expect that to have a significant difference on the results.

If Tony reads this, maybe he can explain the proper way to measure temps to conduct this test.

 

Raytek minitemp gun pointed at the top or sides of the TB. I'm measuring the plenum temp very close to the point where it connects to the TB. With TB shell being made out of aluminum, I would think that it would be conducting heat quite well from the copper piece.

 

I have the same setup. I haven't measured TB temps at all though, I don't have a temp gun to go off of though. I would say that the TB is warmer than the upper plenum though.

How long have you been driving before you measure your temps?

 

My drive this morning was 20 minutes. Is your TB hot to the touch or would you just describe it as warm? And are you in cold weather?

 

Not hot to the touch, just warm.

Utah - 20-30* degrees or so outside for the most part lately. (at least when I'm driving)

 

With the massive heat reduction offered by the motordyne isothermal gasket under the plenum, I could see the TB not getting overly hot, especially with cold south dakota air passing through it. As you mentioned though, your upper plenum seemed to be cooler than the TB which is what I would expect from the copper piece. My TB temp is the same as the upper plenum and is quite cool after interstate driving, moderately warm after city driving. I do have an email sitting with the big man to see what his thoughts are.

 

Performed some additional testing tonight: I idled the engine with the hood open exposed to 20F air for 15 minutes. The TB measured 45F and the top of the plenum measured 55F. My hand confirmed that the TB was colder than the upper plenum right where they connect with each other. I also realized that it is possible to reach back behind the TB and put my finger directly on the copper connector where the coolant line is. The copper tube is definitely super hot on both the in and out side (I'm not sure which is which). I also touched the copper plate right above where the copper line is soldered on and it did feel warm but I wouldn't say it was overly hot. Tony must be tied up as I haven't heard back yet.

I really can't complain as the performance gain has been excellent, heat soak is a thing of the past, and my idle seems perfectly normal. I'm just concerned for my TB since the temps here are bound to head south of 0F any day now.

 

It really shouldn't be much of a problem. You just want the TB to stay warmer than ~32*. Just drive your car hard so you get nice warm coolant flowing through.

The input side of the copper gasket is the side closest to the firewall. comes from the block and flow down to the driverside coolant rail.

 

It is normal for the throttle body to be colder under thoes test conditions.

While at idle there is a high vacuum inside the plenum and with the throttle body in a nearly closed position there is a sudden expansion of the air as it passes by the small throttle plate opening. The sudden expansion of the air is what causes the cooling you noticed by way of the Joule Thompson effect.

Its basically the same way a refrigerator works. Hi pressure gas cools as it flows through a orifice and expands into a larger, lower pressure chamber.

The velocity of the cold expanding gas is high at the choke point of the throttle body and as such, the heat transfer rate is highest at that point. This is what is cooling the throttle body off. This is normal and expected.

It is also the reason for using the Copper throttle body heater. If you didn't have any kind of heat input at that point, it could cause ice to precipitate inside the throttle body, and this is why you want it to be heated. Otherwise the throttle body would be much colder than the ambient temperature.

Never leave your throttle body unheated! This is also the reason why none of the MD spacer kits will leave your throttle body unheated. This is also the reason why every automotive manufacturer heats the throttle body in every car they design. It would be risky to leave it unheated.

The basic spacer leaves the plenum hot all the time. Just like stock.
The Iso Thermal spacer heats the plenum when the CCV is turned on.
The Copper Iso Thermal directs the heat to where it is needed and doesn't need to be adjusted.

Tony