Bypassing Throttle Body Coolant Passage.

C6Racer · April 30, 2008

Hi everyone, this is my first time starting a topic. Couldn't find a thread on this.

I have a 2000 Sierra C1500 with the 5.3L. The throttle body has a coolant passage that warms up the intake air to help the engine run efficiently when it's cold, kind of like the exhaust manifold heat stove that older GM trucks had. I have heard that bypassing that passage will let the TB stay cooler meaning less heat is transferred and therefore producing a more dense air charge which helps make more power.

Has anyone tried that and tested on a dyno? Does it give a significant bump in power or does it just help waste more gas?

Thanks in advance for your input!

Texsrt4 · April 30, 2008

never did it on a truck, but we use to do it on the LS1/LS6 maros and vettes all the time. good for a bit of power, and as long as you dont live where its way cold there should be no real ill effects

redvett · May 1, 2008

Hi everyone, this is my first time starting a topic. Couldn't find a thread on this.
I have a 2000 Sierra C1500 with the 5.3L. The throttle body has a coolant passage that warms up the intake air to help the engine run efficiently when it's cold, kind of like the exhaust manifold heat stove that older GM trucks had. I have heard that bypassing that passage will let the TB stay cooler meaning less heat is transferred and therefore producing a more dense air charge which helps make more power.

Has anyone tried that and tested on a dyno? Does it give a significant bump in power or does it just help waste more gas?

Thanks in advance for your input!

Where you are in CA & warmer climates it OK to do but us northerners can have icing in the winters.

C6Racer · May 1, 2008

Well, where I live it's gonna get up to 90 degrees for the summer so I guess I have nothing to worry about. Maybe in the winter, when it can get down to 25 degrees in the early mornings, I'll put it back on. Thanks for the input!

Lorenzo

Schmids5.3l · May 1, 2008

I did it to mine for fun. I don't really think it's worth too much, everything under the hood is going to get hot anyways, especially if it's part of the engine The way I see it is your constantly sucking in cool air by a 8 cylinder vacuum, so it doesn't have too much time to get warmed up by the hot intake tube, or throttle body. Nitrous sprays @ -100 something degrees Fahrenheit anyways, so I don't have anything to worry about lol

3000 posts

desrtrat · May 2, 2008

i did mine 5 yrs ago, and never had a problem. spent 2 winters in NY. the best way to find out if it is icing, drive it when it's below freezing and check it..after the engine gets up in temp the radiant heat from the motor will keep it from freezing..have never heard of one freezing yet. as for HP increase, i would say 1-3 hp on a cool day

redstreetracer36 · May 22, 2008

is the 1-3hp bump noticable/worth-the-while?

03blackburb · May 22, 2008

There is a flip side to this coin. By removing the TB coolant by pass lines, can cause the TB to run HOTTER than normal. The coolant passing thru the TB removes heat from the TB causing it to be cooler than the surrounding materials.

Schmids5.3l · May 23, 2008

is the 1-3hp bump noticable/worth-the-while?

Hell no, stick with that cam, thats noticeable power. Power costs money

redstreetracer36 · May 23, 2008

was planning on it ..i am probly gonna go ahead and do the other stuff at the same time aswell ..i got to thinking about it last night and am just gonna go ahad and do the whole thing

03blackburb · May 23, 2008

I just had to by pass the TB coolant hoses on my 94 vette. The hoses were starting to swell, so instead of waiting for a rupture, I capped them off while new hoses are ordered. I have noticed over the last 2 days since the bypas was done, my gas mileage has DROPPED about .4 mpg. IMO the coolant will continue to flow thru the TB on my vehicles.

C6Racer · May 27, 2008

I just had to by pass the TB coolant hoses on my 94 vette. The hoses were starting to swell, so instead of waiting for a rupture, I capped them off while new hoses are ordered. I have noticed over the last 2 days since the bypas was done, my gas mileage has DROPPED about .4 mpg. IMO the coolant will continue to flow thru the TB on my vehicles.

Well, lower MPG is a given since a cooler intake charge will mean the air is more dense and therefore more fuel will be fed to the engine = more power! Yes, I'm am willing to sacrifice a bit of MPG for a few horses.