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Old 07-06-2002, 12:55 AM   #1
WRX Joe
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Default Throttle Body coolant line mod

I haven't seen anyone do the TB coolant line mod.
I plan on doing it but wanted to check with you guys first.
I'm talking about removing the coolant line to the TB so the TB wouldn't get as hot as the coolant.
Would this be a good or bad thing to do.
Would the TB get sooo hot that it needs to cool down or is it there to help on really cold days................
I did this on my mustangs TB with no problems.
Has anyone did this and what was your results.
Thanks for your help.............................................. ..Joe
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Old 07-06-2002, 01:05 AM   #2
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If you live in a area that does not see much COLD weather, this is a easy and good mod. You can see upwards of 20-30 degree drop in air temp by re-routing the coolant line so that the throttle body does not receive the hot coolant. As most know, the coolant is designed to keep the throttle body from freezing over when the car is operating in sub-freezing temps. If you do not live in such climates (like myself) then there is no point in the coolant getting anywhere near the throttle body.

Do it and be happy.

By the way, I have run the car for about 2500 miles with no ill-effect, that includes driving thru the Mojove Dessert. No Prob.

Cheers

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Old 07-06-2002, 01:12 AM   #3
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Thanks for the reply
I haven't really looked at it yet ( it's late and my car is sleeping ) but I was planning on using a metal tube to connect to two.
So this way it will flow just as it did but not into the TB.
How did you do it? Thanks............................................ ..Joe:
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Old 07-06-2002, 01:20 AM   #4
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Default Looking at choices

I'm probably going to install a small shutoff valve so In cooler weather I can easily restore the manifold heat given I live in a cold climate.

Larry
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Old 07-06-2002, 01:34 AM   #5
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There's a hose going from the heater core inlet to the TB inlet, and a hose going from the TB outlet to the heater core outlet, which is plainly visible once you remove the intercooler.

You can simply reuse both stock hoses routing one from TB inlet to outlet, and the other connecting the heater core inlet and outlet.
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Old 07-06-2002, 01:39 AM   #6
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.
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Old 07-06-2002, 05:19 AM   #7
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already did this mod a long time ago has worked out great simple simple i would say you shoudl do the tb mod as well port out the lip and knifedge it i also did some other things to the tb but illl keep those a secret...
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Old 07-06-2002, 09:58 AM   #8
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like boostin1320 said. Bypass the coolant and smooth the tb lip and edge the tb plate. You will not be disapointed.
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Old 07-06-2002, 10:22 AM   #9
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Any ideas how cold the temperature has to get for the heat to be necessary? I would think that once the car is running and warmed up, that engine heat should be sufficient. I like the idea of using a bypass/shutoff valve, but, from looking at the routings in the schematic, would probably need to put two of them in to stop the coolant from heating the throttle body by convection. May just re-route hoses - but I'm sure I'll forget to switch them back.
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Old 07-06-2002, 11:46 AM   #10
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do you know what intake temperatures are on a WRX running full boost anyway? I'd guess they're close to the water temperature as long as you're not racing... I'm not saying I know for sure and on a N/A car this a better mod to do, but on a turbo car I'm not sure it makes as large a difference.
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Old 07-06-2002, 12:44 PM   #11
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use to do this mod to Honda engines, they had a funky welded set of lines that was routed like spaghetti from the factory, so the simple bypass was absolutly neccesary when specially with an intake system. (part of the gas blowback system back into the intake)

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Old 07-06-2002, 02:39 PM   #12
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ok-

and to get ingenious what about getting another grainger solenoid and hooking it up the the tb coolant lines to set it up as an on/off type of setup (just like i did with my mbc and the fbc)


WRX300
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Old 07-06-2002, 02:57 PM   #13
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Anyone have any better pictures or links regarding this mod?
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Old 07-06-2002, 06:05 PM   #14
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According to Austin's schematic you'd need a valve at the inlet and a low pressure check-valve at the outlet. This to allow flow in only one direction. If you're getting all that done you might consider getting some steel braided coolant lines, or even silicone coolant lines installed.

Could this really have an effect on performance? The time that the air spends in the TB is miniscule, I think, and therefor lowering the temperature of the TB by even 30 degrees might have very little effect on the exit temperature of the air passing through it. But I haven't tried it...

We need someone's butt dyno to let us know..
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Old 07-06-2002, 06:14 PM   #15
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Back in the 'old' days, one of the first mods you did with a small-block Chevy was to block off the coolant flow from the heads to the manifold under the carburetor for exactly the same purpose. Only had a negative impact on cold start-up as the manifold soon reached the same temperature as the rest of the engine. Was primarily a drag-racing trick - but we all did it - and all aftermarket manifolds have no crossover passages. Would figure the results to be the same here.
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Old 07-07-2002, 12:28 AM   #16
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Thanks for all the input.
I will do the TB mod and knife the TB as well.
I just have to wait until I have some time................JOE
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Old 07-07-2002, 01:57 AM   #17
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Well, this may and may not work properly.

I live in Florida.. so we don't see super cold winters obviously.

On my previous car, a 2000 Honda Prelude.. I did the throttle-body bypass mod like you guys are talking about, and in the winter, of tempratures around 40ish to 45ish degrees the car wouldn't idle right. At idle, the rpms would raise to 1500 then drop down to 800, then back up to 1500, then down again, it went up and down up and down up and down constantly. Very annoying because your car is making the Wahhhh--Ooooo_---Waaahh--oOoooo sound the whole time. The reason for this was because the Prelude engine (H22A) had a temp sensor in the throttle body that when the throttlebody reached a certain temprature it would lower the car's idling rpms. Just like how your car holds higher rpms while cold to heat the engine up faster. Well, since there wasn't any coolant going through the tbody to heat it up, the sensor freaked and didn't know where to hold the idle. It also caused a strange problem where while driving the car would drop to idle! It was nuts, i'd be driving 80 mph and then the car would sputter and my rpms would be at 800 and giving it gas wouldn't do a thing.

What i'm concerned with is if the WRX does the same thing... if not, we're in the green and gain probably 2-3 whp from this free mod. If not, i'm staying away from it, because if it's slightly cool outside, you're going to have problems.

Jay
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Old 07-09-2002, 11:12 PM   #18
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Well, I have it done to mine and did it to my DSM when I had it, even in snowing conditions. The coolant does spend very little time in the TB, but that is even worse for heat transfer. That means that the coolant will not reduce temperature much, so there is always full hot coolant in the TB. The TB does already have a solenoid in there (I believe) that only lets it flow during warmup conditions(convection) but it can still transfer heat even when it isn't flowing (conduction) ableit to a lesser degree. To visualize, it's somewhat like windchill factor. The faster the medium is flowing around you, the more you are going to "feel" it. The mod doesn't require any parts whatsoever. Just take the feed hose to the TB and run the TB side of this hose over to where the other coolant line connects into the trunk. You can reattach it in the winter simply by removing the IC.

HTH
Mark
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Old 07-10-2002, 12:00 AM   #19
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Thanks for the info.
I found some time the other day and did the TB coolant line thing and while I was at it I ported the TB as well.
It seems to spike a little more now and feels a little stronger up top............................................... ...............Joe
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Old 07-10-2002, 08:51 AM   #20
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a freind of mine did this mod to his maxima, and didn't see any worthwhile improvement. his idle is also inconsistent. it is weird how different cars respond to the same exact mod. mike
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Old 07-10-2002, 09:27 AM   #21
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hotrod,

When you do this, let us know how it works for your particular situation.

Thanks,

GoodFinder
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Old 07-10-2002, 09:56 AM   #22
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Quote:
Originally posted by WizardBlackWRX
Well, I have it done to mine and did it to my DSM when I had it, even in snowing conditions. The coolant does spend very little time in the TB, but that is even worse for heat transfer. That means that the coolant will not reduce temperature much, so there is always full hot coolant in the TB. The TB does already have a solenoid in there (I believe) that only lets it flow during warmup conditions(convection) but it can still transfer heat even when it isn't flowing (conduction) ableit to a lesser degree. To visualize, it's somewhat like windchill factor. The faster the medium is flowing around you, the more you are going to "feel" it. The mod doesn't require any parts whatsoever. Just take the feed hose to the TB and run the TB side of this hose over to where the other coolant line connects into the trunk. You can reattach it in the winter simply by removing the IC.

HTH
Mark
QR
Agreed.. just hook it up in the winter again.

Jorge (RiftsWRX)
www.ProjectWRX.com
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Old 07-10-2002, 10:14 AM   #23
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will this work. once you reroute the tb lines there will be an inlet and outlet open that will pass through the throttlbe body. can you run something cold through it. nos, co2, ice cold water, who knows. just an idea.
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Old 07-10-2002, 10:27 AM   #24
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i've never heard of this mod before, sounds interesting...can someone do a write up for scoobymods.com? i'd be interest in it for sure.......please don't tell me to re-read the thread as the info is scattered and doesn't seem to be complete.......

tia
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Old 07-10-2002, 10:31 AM   #25
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Quote:
Originally posted by newbie sewbie
i've never heard of this mod before, sounds interesting...can someone do a write up for scoobymods.com? i'd be interest in it for sure.......please don't tell me to re-read the thread as the info is scattered and doesn't seem to be complete.......

tia
I'll do better... search 6 months back...

Jorge (RiftsWRX)
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