Throttlebody Coolant Bypass
 

One of my friends was telling me that he did a throttlebody bypass on his MSM. Apparently the coolant runs throught the throttlebody to prevent it from freezing in severe cold weather. According to him by rerouting the coolant to bypass the throttlebody you're able to keep intake temps cooler. I tried searching for people doing that but wasn't able to find anything.

Given that I live in south Florida where it never freezes, and even if it did freeze I hate cold weather and my car has no top, no windows, and no heater so it certainly won't be leaving the garage if it's under 50 degrees, are there any drawback to doing the reroute? Is the coolant serving any other purpose than warming up air going into the motor?

do it.

what's colder: 190-210°F coolant temps or 40-120°F ambient temps?

http://www.boostedmiata.com/random/idle_passages.jpg

[QUOTE=Braineack;380467]what's colder: 190-210°F coolant temps or 40-120°F ambient temps?

So uhh, I did the math and it appears the ambient temps would be cooler.

Is 190-210 the coolant temps we're supposed to be running? Whoops. I gotta do something about the begi reroute! :bang:

More specifically though, what is the easiest way to bypass this system? Just run the line that would normally go into the peice under the throttle body to wherever the out from the air valve on the manifold goes?

and really the coolant only passes through the idle valve...

After careful calculations I came to the same conclusion.

190-210 is high for a car with a nicely done collant system. Don't sweat it. I never hit 200 unless I forget to turn my fans on in stop and go traffic.

Even if I had the most efficient cooling system in the world, I'd still want to operate the motor somewhere between 190-200°F

:shrug: I idle during the day at about 185 (180* thremostat) and doing repeated pulls on the highway get up to maybe 195* - all according to MS reading the stock sensor. My aftermarket water temp gauge who's sensor is in the upper radiator hose sees lower temps as that's right after cooling in the rad. At night, cruising/idling is just about flat 180*.. this is with just a larger koyo alum. rad and both fans on switches in the cabin so I can run one or both on demand.

Upper radiator hose is the return from the engine to the radiator. Coolant flows in to the engine from the radiator via the lower radiator hose.

190-200* ftw!

You are right I am wrong... not sure why I was thinking the flow was backwards. Anyways, having that sensor after the thermostat means it doesn't read until the water gets up to temp and then the thermostat opens, so if ever the thermostat was stuck, I'd know immediately b/c the stock gauge would be reading and the aftermarket one would not.

One 11" spal and a big radiator kept my motor at 194-197 with no reroute. Reroute, one Spal and a 180 degree thermostat and I'm at 184-187.

Forgive my dumb question but; what did your friend do with the coolant line he was bypassing?

i was told that the coolant flowing through the ISC valve is actually to cool it. so... cutting off the coolant flow could cause it to burn out.

There is one line going in the throttle body and one coming out. Unhook both of them and connect the lines. I did it when I got home from work today, took about 10 minutes and everything seems to be working fine, so apparently it works.

pics?

Thanks.

+1 on pics whenever you can.

Man, I can't help but feel like you guys are all just mocking me, telling me to do some dumb shit that no one in their right mind would do, then when I actually say that I do it you ask for pictures so you can take the mockery to a whole new level, and eventually it spreads all over the internet... I really hope I'm not "that guy", sigh...

I tried to take some pics, but it's hard to get a shot of. It's really one of those things that when you look at it, it's very very simple.

http://i272.photobucket.com/albums/j...DSCF0762-1.jpg

In the pic you can see the inlet on the throttle body and the hoses bypassing the throttle body. The outlet on the throttle body is behind the inlet (can't be seen in the pic). If you look at it on your car, it should be pretty self explanatory I think.

Hey pdexta; thanks for the pics and...I'm in no position to mock anyone when it comes to things mechanical :giggle:

Dude, I totally can't believe you just did that.

burn up? what's going to cause it to burn up? the heat radiating from the alternator?

it's to prevent the valve from frosting/sticking in extreme weather.

I think he's playing with you.

You can laugh now...you're not the butt of some epic pwnage.

I'm about to go out into the garage and do the same thing. I'm a little bit of an idiot too, so if we're wrong they can laugh at us together.

I just wonder how much of a difference it makes.


I'm sure that once everything is up to operating temps, you can assume that the throttle body is atleast 50-60 degrees above ambient. It actually has a decent sized area that is convecting heat to the intake charge, but is small compared to the intercooler. also, the rest of the intake manifold is heated by the head anyhow, and has a MUCH greater internal area.

I'm sure every little bit helps though, and for the ease of routing a hose, it should be done. Well, atleast if you live in parts of Texas where it only freezes once a year.

I love insecurities. I own a few myself.

I'm pretty sure I picked up at least 50hp. :giggle:

Drag racers used to rant about this. The real reason other than de-icing (which never happens) is to keep the PCV vapors liquid enough, otherwise the throttle butterfly can get gunked up. THere's an absolutely negligible difference from removing the warming loop, you won't even get a degree of difference at any airflow where you'd make power.

I kept reading idiocy on many forums about insulating pipes or removing that bypass. I tried it on my old Mitusbishi Mirage with a thermocouple screwed into the intake manifold. I lost one degree at idle (highest heating potential) removing it. Related to that was that I put a steel section in the intake and heated it to 1800deg F with a MAPP torch. 5 degrees at idle, thats it.

Now, on the other hand, application of the extremes of that theory is true. A compressor outlet to charge cooler pipe can reject HUGE amounts of heat until the pipe reaches the outlet temperature, but the temperature changes are much more extreme than some 180F coolant touching a few square inches of air.