hi.

i was just wondering if any of you prelude folk have tried the coolant bypass (removing the coolant lines from TB/IM) and the length of time you have had this done? i was curious if there were any problems you all may have ran into down the road... like long term. thanks

 

lol......gettin worried or somethin mike?

 

nope, just bored/curious... i didnt even ask before i did it, so i figured why not.

 

i did it to my Lude, it makes your car idel wierd like up and down, i stoped this by putting a fitted peace of sheet metal across where the coldstart valve is. other then the idle problem i havent had any problems at all. I did it back in January on my old engine and i have it done to the engine i have in my car now.

 

If it ever gets really really could out your TB could freez shut. The line is there to keep your TB worm, and the car idles better with it in. Other than that I can't think of anything. Next time I get my car dynode I will try it with and with out the bypass and post if it really gives gains or not.

 

I have had this done for almost 3 yrs now. As long as you place a gasket between the tb and the fast idle valve (located under the tb) you wont have any Idle issues, such as surging.

 

well, i live in the friggin desert, so i dont have to worry about it getting too cold here.

yeah, i had the surging problem at first, then i just used some blue rtv w/ the little o-ring gaskets and it solved it right up.

thanks for the replys fellas.

 

What is the advantage of doing this?

 

" This is an old trick that V8 guys have been using for years. It involves bypassing the coolant lines that normally course coolant through the throttle body to keep it from freezing up in the winter time. But in the summer and in areas with year-round warm climates, this coolant adds unneeded heat to the intake charge into the engine. So bypassing these coolant lines could feasibly free up a few horsepower."
source: http://prelude.vtec.net/gen5/performance/tips/tbcoolant/

 

ya what cognee said plus it takes a whole lot of ugly *** coolant lines away, looks much cleaner around the TB in my opinion.

 

Not cosmetic!

Understand that coolent heats up, well above a cold oxygen temperature, when hot coolent runs though a intake manifold it inturns heats up oxygen.

The purpose of coolent running though a intake manifold is to steady idle; cold start and sometimes otherwise. You will notice a change in idle, however a slight increase in performance. Not much, but for you NA guys, such as myself, it is a very good idea. Unless you live in a very cold winter area...

http://lyonel.8m.com - search though tech and how to's. Great stuff, good job lyonel...

 

i know its not a cosmetic mod, i said as a PLUS that it makes a lil more room around the TB, which cleans it up a lil bit too.

 

Forgot to add one other reason why the coolant lines goto TB housing. There is a valve, actually 2 of then, that open up to let air bypass your throttle when the coolant is cold. This will make your car idle faster by a few hundred RPM until the engine is up to operating temperature. So, it is also one of the many ways your car tries to keep your engine temp constant. Ie. Radiator, fans, thermostat....

So I would think by not running collant, the valve will think it is cold all the time and stay open. This will make your car idle a little faster than norm = use more gass.

Also if ya look were the coolent goes, it just goes in and makes a U-turn and comes right back out. I'm not sure a hole hell of a lot of heat is making it to the intake air. I'm willing to bet this mod will show no HP gain on a dyno. Has anyone tryed it on a dyno 1st hand??


[Modified by 57STS, 11:50 AM 9/18/2002]


[Modified by 57STS, 1:01 PM 9/18/2002]

 

Exactly how are you guys bypassing the fast idle valve? Someone said to put a gasket over it; I take it they mean make a template and cut a plate to cover the hole and then use RTV silicone btw the plate and the TB. What about the coolant line that attaches to the fast idle valve? What do you do with it?

I guess you could just leave everything hooked up as normal and then just put a plate between the fast idle valve and the TB couldnt you OR between the coolant housing and the fast idle valve...like this:

 

I have been considering this mod also. PLease explain the gasket part.

 

Welp,

This is what I did. I dont know yet if it works and I dont know when I will put it on, but here goes!

http://63.144.16.232/browsable/honda-tech/iacmod/

 

see the three bolts, one is right next to the ??? and another is holding on that bracket, and together they make up a triangle, well sorta. you take those three out, and need to buy shorter bolts, much shorter bolts. then you cut something to size to block it and seal it. seal it very good or you will get the idle surge.

i suppose you dont have to buy shorter bolts, you can just leave the FIV on and put a block plate between it and the TB.


[Modified by exaccord, 5:39 PM 9/25/2002]

 

Heh, like this? I just did this! I dont know when I will get a chance to put it on though and see if it works.

http://63.144.16.232/browsable/honda-tech/iacmod/




[Modified by CaNaBiS, 7:40 PM 9/25/2002]

 

whats the point of making the block plate if you just put a hole in it?

 

i removed the hole assembly, how i explained in the above post, im not positive that what you did will net the same result.

 

It still covers up the coolant hole....oooh wait...I dont think that will work either. Hermmm....

 

Uh, yeah, the above mod wouldnt work. Dont anyone do it. Its all jacked up. I dont know what I was thinking....been smoking a little too much weed today!

 

thats what im saying, you need to block the whole thing off. remove those 3 bolts i was trying to describe, then you will see what im talking about. to seal it up i used the 3 little rubber o-ring gaskets that you will find when you remove the whole thing. i smashed inbetween a block plate and some rtv.

 

I did it 2-3 years ago. No probs. Some of my friends have done it too with no problem.