engine question

[4Runninfun]

Alright i'll preface this question with why i'm asking. I bought a motor for my yota with all the emissions and much of the vacuum crap removed or blocked off. As with anything i do to my truck I really try to consider all consquences of an action before just diving in. I figure if an engineer put something on the motor it is there for a reason, maybe that reason applies to my application like better MPG or better performance or maybe it doesn't such as emissions equipment. and as with any system modify or change one componet and that will generally have some sort of impact to the entire system. kind of wordy, " why i'm doing this" but what i'm trying to avoid is simple answers like "do it and see what happens", or " i did it and i'm fine" I can always experiment on my own. i'm looking for more of a detailed explanation.

First up the EGR valve... understand this is primarly an emissions requirement deal. besides recirculating exhaust gasses what other functions does it perform? I have heard that removing this will lead to hotter exhaust temps, which obviously are negative. what effects will there be by removing this from the system?

Next I have seen on other throttlebodies besides my own that there are coolant in/out ports, which i would assume are designed to heat up the TB, why? This would seam to also heat up the air inside the plenum, is this a good or bad thing? I can see if you would want warmer air because it can carry more fuel vapor with it (saturation), but then also cooler air is more dense and thus there are all sorts of things designed to flow cooler air into the motor, so this would seam to defeat that. what effects are there to leaving this on vs disconnecting the coolant lines?

Charcoal canister besides something that looks like a complete afterthought on a lot of cars is this really necessary?

Thanks for any input. hopping to find out what i REALLY need to put back on and what i can omit and clean up all the damn vacuum lines.

[WINKY]

i think the coolant lines through the throttle body assist in keeping the throttle body from getting to the temp of the engine head/too hot (causing vapor lock). Also it can assist in getting the throttle body to temp a bit faster with hot water running through it while the block is still cold... Having this would be better then just leaving it hot on the engine. I know DR UNIT's fj has a blower fan ducted to his throttlebody from external air.

anyone chime in to correct my thoughts :)

---------- Post added at 02:26 AM ---------- Previous post was at 02:17 AM ----------

as far as the egr valve i dont understand the idea of injecting hot gas into cold air cooling it down...??? lol i would think that putting exhaust into anything will reduce power made (less fuel due to less "air" being pulled in). it is there to reduce NOX (nitrogen related gasses) for emissions like you said.

now the exhaust getting hotter with it removed is plausible being that you have more fuel with the air being pulled in without the egr recirculation. but this should balance itself out with the o2 sensor getting correct air fuel mix... i dont think the egr valve does anything else.

[Brody]

Some stuff I found for you:

[QUOTE=4Runninfun;66981]

First up the EGR valve... understand this is primarly an emissions requirement deal. besides recirculating exhaust gasses what other functions does it perform? I have heard that removing this will lead to hotter exhaust temps, which obviously are negative. what effects will there be by removing this from the system?

From pirate4x4:

I removed the EGR and all related components on my truck. The only vacuum lines I have hooked up are, vacuum booster, PCV hose front and rear, line to power steering thingy and vacuum hose to charcoal canister for the fuel tank. http://www.pirate4x4.com/forum/images/smilies/smile.gif

From Toyota Land:

Why do you want to lose the EGR system so bad? It doesn't have any detrimental effects on performance. In fact, other than a smog pump and the catalytic converter, none of the emissions systems have any detrimental effect.


From IH8MUD:

X2. I think it would take some work to make the computer not throw a code, if it is even possible. You are OBD2. It will throw a code the first time you drive it. EGR is there for a reason. It helps your engine, reducing combustion temps to reduce pre-ignition/detonation which kills an engine. And if you go to sell it, or you move to another state that requires it, you will regret it then. I would leave it for sure.

Next I have seen on other throttlebodies besides my own that there are coolant in/out ports, which i would assume are designed to heat up the TB, why? This would seam to also heat up the air inside the plenum, is this a good or bad thing? I can see if you would want warmer air because it can carry more fuel vapor with it (saturation), but then also cooler air is more dense and thus there are all sorts of things designed to flow cooler air into the motor, so this would seam to defeat that. what effects are there to leaving this on vs disconnecting the coolant lines?

From EvoTuners:

Throttle body coolant lines.
Question: Why does the EVO have coolant lines to the throttle body, and can I remove them as a free mod for more power (http://www.evotuners.net/forums/#)?

Answer:

The DSM and EVO throttle bodies have two mechanical and one electric control of idle speed.

The electric control is the stepper motor (http://www.evotuners.net/forums/#) controlled by the ECU that opens up a bit to raise idle, and closes to lower idle.

The first mechanical idle control is the Base Idle Set Screw (BISS) The BISS is a screw that blocks off a passage that allows airflow to bypass the throttle plate. You turn the screw out and more air bypasses the throttle plate raising your idle, turn the screw in and less air is bypassing the throttle plate and your idle goes down.

The second mechanical idle control is the Fast Idle Air Valve (FIAV) The FIAV is a plastic/wax plug that blocks off a passage that allows airflow to bypass the throttle plate. When this plug is cold is shrinks and blocks less of the air passage and more air bypasses the throttle plate raising your idle, as the coolant heats up, the plug gets warm and expands blocking more of the air passage so less air is bypassing the throttle plate and your idle goes down.

If you get ride of the coolant lines to the throttle body, the car (http://www.evotuners.net/forums/#) will remain in "high idle mode" because the FIAV never warms up enough to expand blocking its air passage. If you live in a warm climate where a fast idle to warm up the engine is not that big of a deal you can bypass the lines if you like and the electric idle control combined with a one time BISS adjustment will have you idling fine. If you live in a cold climate you will need to make seasonal adjustments of the BISS for the car to idle correctly in each season because the electronic idle control will be out of its range of adjustment if you don’t compensate with the BISS.

The throttle body is heated by a combination of the coolant running through it, and by heat conducted up through the intake manifold from the head and into the throttle body. Any power gain from not heating up the throttle body with coolant is theoretical, and the throttle body may in fact be cooled by the coolant depending on how hot the intake manifold gets on our cars (http://www.evotuners.net/forums/#)... I do not have data on that issue. No matter weather the coolant has any cooling affect after the intake manifold heats up or not, the air spends so little time in the throttle body at WOT that in my opinion the affect on power would be negligible to the point of being non-existent.

Keith
____________________________
EVO 11.53 @ 123.37, Black WRX Wagon 13.62 @ 99.24
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Charcoal canister besides something that looks like a complete afterthought on a lot of cars is this really necessary?

From WIKI Answers:

It captures fuel vapors and prevents them from escaping to the atmosphere and then stores the fumes and recycles them to the fuel tank or engine intake for combustion as needed.
The long and short of it is that it helps to protect the environment and improve fuel economy.

Thanks for any input. hopping to find out what i REALLY need to put back on and what i can omit and clean up all the damn vacuum lines.

[4Runninfun]

Brody-

Thanks for the info. Looks like i'm going to put the EGR and the Coolant lines back on and remove the block off plates. I don't really like all the vacuum lines but i've messed with them so much now that I know where they all go pretty much from memory.

[Brody]

I was glad that you asked the questions. I read the links and learned stuff, too, some of which I knew a little bit about. It was interesting reading...

[Funrover]

Jon are you going to need any help with anything?

[4Runninfun]

I've pretty much got all the major parts in now, just a few things left to hook up and bolt on. But if you're not doing anything next time i'm out there i'll give ya a shout.

And thats kinda what i figured. I know most on here have a basic understanding about these things, so i figured more than just me might find this interesting.