Why does coolant run through the throttle body on a EA82T? What is its purpose? I am just trying to understand my sube a little better.

Officially, to prevent icing of the throttle body, in secret, to provide an oppertunity to sell a 4 inch hose for $65.

Coolant runs through all the stock intake's - carb's too. I have heard that when the engine is warm, it can reduce the HP by quite a bit. The guy I talked to said the EA81's are tested cold, and produce about 75-80 HP. When warm this drops to around 65 HP (for a stock engine). There is no need for the coolant passage really - other than emmissions. Even Subaru did away with it on their race engines of the time I think. I suppose there could be a seperate cross-over on this bad boy, but I doubt it...

 

 

GD

it's supposedly for icing

 

i've heard that for 1 degree cooler intake charge you gain 1 hp.

 

So...just bypass it with some hose...and everything will be good

does anyone else have any opinions? or why coolant runs through the intake mani at all...unless thats the only way it gets to the TB. this interests me...I live in AZ, so icing is unheard of (at least in Phoenix) unless icing is a term that means something else other than what it implies...if it will help keep my car cooler, its getting bypassed!

It's also where the coolant temp sensor is located - which is important on FI and feedback carb models. They will run like crap if that sensor thinks the engine is cold....

 

It's not easy to bypass - you will have to make a custom manifold, or heavily modify the existing manifold. Wouldn't be terribly hard to just block it off completely. Not sure if that's a good idea tho.

 

GD

Here is what I got from a google search on icing and throttle bodies:

http://www.ellison-fluid-systems.com/faqs/carburetor_heat.htm

 

So it seems that icing is caused by the evaporation of fuel. For a second there, I thought icing was only possible if you live in cold climate .

uhhh.. icing is only a problem in carbed motors ...

on fuel inejcted it runs through the throttle body mostly to help the engine warm up faster

in other words emmision nazi crap

and yes the hotter the air going in the less power going out

it also increases teh chance of detonation

as far as the temp sensor location... i thought it was that doohicky mounted right under the thermostat on regular ea82t's and mounted in the water passage on the spyder style intakes from looking at this spyder i have blockign that off is easy and will be done

i am not sure how it is done on the standard ea82t intakes have not pulled mine apart yet

there are two coolant sensors, one for the gauge and one for the computer...I think the one for the computer is on the firewall side of the intake mani...I will have to look into what it takes to bypass this passage...

So will bypassing the coolant line increase emissions significantly? I want to know if I can get away with that in CA.

 

A little off topic but...

The EGR routes warm exhaust gas back into the intake. So will that give a greater chance of detonation? I remember somebody on the board saying that the EGR will help decrease the chance of detonation on a turbo car.

 

Here is a quote from skip:

This does make sense, the purpose of the introduction of exhaust gas into the intake is to lower the combustion chamber temp, thus reducing oxides of Nitrogen.

The turbo needs any help it can get in lowering the comb. chamber temp, this in an effort to reduce pre-ignition and detonation.

Many thanks to Mike for the excellent picts

and

to Caleb for doing the search and posting the link

http://www.ultimatesubaru.org/forum/showthread.php?t=9399&highlight=spider

i believe the ratio is 11degrees F is equal to 1 hp.

1:1 would rule!

cut it and cap it.

The catalytic converter does a great job with emissions...the problem is, it doesnt work well until it warms up. thats why your car smells when you first start it in the morning. its called cold start, so emission nazis do what they can to heat your car up as fast as possible (ie coolant keeping intake temps up) thats also why cats are getting closer and closer to the exhaust manifolds, to heat up quicker.

 

I think in cali they do underhood inspections and if they notice that you did something, they may fail you before you even get to the smog test...if you go to get emissioned, make sure the car is nice and warm. Drive around town for awhile before hand.

 

Theres other tricks emission people have too, and some of the others on this board are emission inspectors so maybe they will chime in and give you better info than I could...

eric