Thoughts on the coolant bypass mod after 3 days.
Thread Starter
VTEC MASTER
Joined: Mar 2004
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Thoughts on the coolant bypass mod after 3 days. 
After driving awhile, the throttle body is cool to the touch! The hoses that you splice together are too hot to hold! And no, the throttle body isnt hot whereas the rest of the engine is. I dont know why. There is a deffinite difference in accelleration in all areas of the powerband.
Joined: Sep 2002
Posts: 51,241
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From: NV
Rep Power: 813 
There are hoses that route engine coolant into the throttle body to keep the valve from freezing shut in the winter. Unfortunately, this also heats up the TB in the summer (and the incoming air, so worse performance). If it gets below freezing and you did this mod, bad things could happen.
Joined: Sep 2002
Posts: 51,241
Likes: 20
From: NV
Rep Power: 813 Some good info. Read all of it.
4.6 What's the coolant bypass modification?
Radiator fluid is passed through the throttle body to keep it from freezing
shut. This also heats the air going into the motor. By removing the lines
from the throttle body and connecting them together, you avoid the air
heating up. So expect more power. Don't do this if it snows in your town.
From Ali J. (muaythai@sure.net) :
Another easy modification to cool things off is locating the coolant pipes
that lead to the throttle body, and using a "Straight T" attach them.
This will bypass the throttle body and keep it cool. After all these
modifications, I used an air temperature meter to compare this system and
my AEM cold air system. The AEM system runs 72-152 degrees, while my system
runs a cool 58-110 degrees.
WARNING! You may not want to do this trick since it may cause your
car's warming up idle to fluctuate! Somehow you need to warm up
the fast idle thermo valve (which mounts on the underside of the TB and the
hoses connect to). Once someone figures out how to keep this happy,
it should be a streetable modification.
Radiator fluid is passed through the throttle body to keep it from freezing
shut. This also heats the air going into the motor. By removing the lines
from the throttle body and connecting them together, you avoid the air
heating up. So expect more power. Don't do this if it snows in your town.
From Ali J. (muaythai@sure.net) :
Another easy modification to cool things off is locating the coolant pipes
that lead to the throttle body, and using a "Straight T" attach them.
This will bypass the throttle body and keep it cool. After all these
modifications, I used an air temperature meter to compare this system and
my AEM cold air system. The AEM system runs 72-152 degrees, while my system
runs a cool 58-110 degrees.
WARNING! You may not want to do this trick since it may cause your
car's warming up idle to fluctuate! Somehow you need to warm up
the fast idle thermo valve (which mounts on the underside of the TB and the
hoses connect to). Once someone figures out how to keep this happy,
it should be a streetable modification.
yup.. i think imma do that next weekend... but instead of removing the whole thing.. i think imma put in a shutoff valve so i can turn off the fluid that runs to the throttlebody during summmer and if i go to the mountains and stuff where it snows in the winter imma just run the valve open... hmm.. something to try.. if i do it imma post some pics up
Originally Posted by gearbox
WARNING! You may not want to do this trick since it may cause your
car's warming up idle to fluctuate! Somehow you need to warm up
the fast idle thermo valve (which mounts on the underside of the TB and the
hoses connect to). Once someone figures out how to keep this happy,
it should be a streetable modification.
car's warming up idle to fluctuate! Somehow you need to warm up
the fast idle thermo valve (which mounts on the underside of the TB and the
hoses connect to). Once someone figures out how to keep this happy,
it should be a streetable modification.
Joined: Sep 2002
Posts: 51,241
Likes: 20
From: NV
Rep Power: 813 Yeah my bad. I don't think our cars have that part. Instead, the ecu makes the fuel mixture really rich for a minute until the cat gets up to temp.
A shutoff valve would work well to turn it on/off.
A shutoff valve would work well to turn it on/off.
Originally Posted by xproductionz
anyone know what size fitting the hose is so i can buy the shutoff valve
If you find one let me know where you got it. Ok?
I looked today and couldn't find jack. I think My hose I bought was 5/16 I.D.
Thread Starter
VTEC MASTER
Joined: Mar 2004
Posts: 710
Likes: 0
Rep Power: 0 Dont put in a shutoff. The water needs to circulate. Just get a brass fitting from the hardware store. Its about 1/4 diameter and 2 in long with some threads on each end. They will help keep the hoses in place when clamped down.
Last edited by redvtec04; Aug 15, 2004 at 10:24 PM.
i wasnt really thinking of shutoff vavle..i was thinking more of a (i think they call it a 3 way valve) where u turn it one way it routes it into the throttle body then if u turn it the other way bypasses the throttle body might require a few extra hoses but i'm up for it
caution: Don not under any circumstances perform and DIY's while under the influence of Alcohol. I did the tb bypass and I left out a small step in the DIY (you know the part were you put a pipe to connect both hoses) to say the least it sucked. the afternoon after (i did it late at night) while i was driving to the grocery store my temp guage went to almost the red line, I pulled over and coolant (I'd say %80 or more) was leaking out of the hoses. Yes I know I'm a dumbfuc. but its all better now. :-)
Joined: Sep 2002
Posts: 51,241
Likes: 20
From: NV
Rep Power: 813 Man that sucks. But I think this mod will help some. That coolant gets hot enough to burn you, so keeping it out of the tb is a good thing in summertime.
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