Anybody else bypass coolant lines to throttle body?

[modifyer]

I hear you , it certainly has nothing to do with enhancing power so as for beating it to death it hear who cares . The discussion would be better left in the manufacturerers engineering dept. or with the driveclean guys .

 

[crankbender]

Originally posted by DSMJim
Thats the theory. I don't know enough that I can clearly explain how and why it works. I just know from what I have done and the courses I have been on that EGR is "supposed" to give better economy. I have yet to test my own car out to see if this happens or not. If anything it's going to be a negligable difference. We both agree that it reduced NOx which is the primary function. After that I don't know a whole lot more, nor do I really see fit to study EGR to death either..

Many manufacturers use egr gas and run really reallly lean during cruising conditions. DSMs don't do this. My mazda drops to .05 on the O2 sensor during cruising because of this.

The EGR actually dirties the intake on a DSM and therefore reduces efficiency and max power at WOT. It is better for the engine (not environment) to take it off.

 

[painmaster]

IMO just disconnecting the coolant lines to the throttle body is pointless. I tired this on my car and found that, depending on the engine temp, my wax plunger for the FIAV would open and close without water flowing to it. This caused the car to run iradically. If I were to try it again, which I dont think I would, I would completely block the FIAV off.

There is an article on the VFAQ about this.

www.vfaq.com under INTAKE, and FAST IDLE AIR VALVE BLOCKOFF.

 

[herostar]

this is a great post

on the topic of dirtying the intake... anyone who has removed their TB and/or intake manifold has seen what the egr does. All that nasty black stuff is from the EGR.

 

[dsmturboawd]

benifits from the egr are worth it.

who cares if its dirty in your manfold.

 

[clownface]

i just thought of something, please dont flame me if it sounds silly or if it is silly, hehe, if EGR is sooo great then why dont any of these high flowing intake manifolds have it so you can use EGR? i havnt seen any that are setup for EGR, so maybe it is better not to have it performance wise?

 

[dsmturboawd]

cause its emissions.

 

[TransAmConvert]

The only point of blocking the EGR is to remove the vacuum lines and solenoids associated with it to clean up the engine bay and reduce potential leaks. Or if you just hate mother earth and want to make as much pollution as possible at all times It really wont significantly effect mileage one way or another. Racers don't have it because of the KISS principle. If you don't need it, don't put it on.

If you do a TB bypass you must also remove the FIAV. If you live up north, this is probably a bad idea. I highly doubt it would make any difference in intake temperatures, but I have no proof one way or another.

 

[Bohrn]

2 things.

1. Blocking off your throttle body coolant and EGR are not performance mods.

2. Our cars were not designed to have EGR's (1g anyways) but were added on afterwards for the North American market. I figure they may work better without them as that is how they were designed.

that said, if your FIAV is dead, you will benefit greatly by blocking it off and bypassing those coolant lines. As you can't buy just that valve, and a used throttle body is probably going to have its FAIV die soon too.

As well, if you do bypass the coolant, it makes removing your throttle body WAY easier If you need to put in new throttle shaft seals, new gaskets, a phenolic spacer on the intake manny, get some room to work, or whatever, its just 4 bolts and the elbow rubber.

As for pollution and mileage, I have my EGR blocked off and I have very excellent emmissions test readings. 0.00 in some cases. My NOX could be lower but its not at all bad. And I have seen the inside of my intake manifold and its GROSS!!! Its coming off as soon as my phenolic spacer gets here.

I also go 450km on a tank, regularly and in city driving. With 75# injectors and a Wally 255, making power to go 12's if the clutch would hold up its end of the deal.

Not disagreeing with the science or anyone here, just sharing my experience.

 

[92tsifwd]

That's why I did it, I was getting idle surge and it eliminated a boost leak also. I left the egr on for better gas millage though.

 

[sweet97]

Having the EGR operational does increase gas mileage. i have read of one DSM'er going from 19 to 23 MPG with the EGR operational. The exhaust gas also cools the combustion chamber which could eliminate part throttle knock and once there is knock happening it is likely to carry into WOT operation also as hot spots occur. I plan on testing the EGR for mileage and then posting the results. If I can gain 4 MPG that would be significant and reducing knock is also a plus. Let ya know. mark

 

[Rice Over Wheat]

Sorry for reviving this old thread, but none of the posts cover my question.

I had a coolant line break yesterday and had AAA tow my car back to a shop. Turns out a previous owner must have done the coolant bypass because only then did I realize there were two hoses off the TB that were just sitting there open. Anyway, I didn't like that and figured mitsubishi had it going to the TB for a reason so I had it fixed back to stock configuration.

Question is...where before my coolant temps averaged around 206 with bypass, now I avg 210 with coolant back to stock routing. Anyone have any idea why that is? And no one has suggested why mits ran coolant to the TB anyway....?

 

[Bohrn]

I betcha someone has blocked off the fast idle air valve. This is a good and permanent fix for idle surge when cold.

Now, to do this correctly, you bypass the coolant passages in the throttle body.

If you just hooked them up again, but the fiav is not working correctly, its probably plugging or partially plugging up the coolant hoses.

PS, even 206 is pretty high considering its winter. I only see that temp when sitting in summer traffic, and only occasionally.

 

[nightspeed87]

I blocked mine so that I could remove more crap that I didn't need from the engine bay. It's as simple as that.

Yea this is my basic reason for doing it as well.
But currently my egr valve is still there I just stuck screws in it and removed the vaccum lines
to close it off because I havent gotten a block off plate yet which I will.
I am also going to remove the tb coolant lines from the FIAV as well just because
there then will be less down there. Whether its in the way or not I just want to minimize
unnessities in the engine bay.
( Like cruise control, and half of those solenoids on the firewall )

 

[Rice Over Wheat]

^^^

Cruise control? I cannot live without it.

I betcha someone has blocked off the fast idle air valve. This is a good and permanent fix for idle surge when cold.

Now, to do this correctly, you bypass the coolant passages in the throttle body.

If you just hooked them up again, but the fiav is not working correctly, its probably plugging or partially plugging up the coolant hoses.

PS, even 206 is pretty high considering its winter. I only see that temp when sitting in summer traffic, and only occasionally.

Well it doesn't get much cooler than 70 mid-day in central FL. It's possible it was done for the FIAV however I wouldn't know since my idle sensor control motor is shot and I get surge anyway.

I guess I'm just wondering why mits ran coolant through the tb in the first place...

 

[Bohrn]

they ran it thru to allow the fiav to work. As the coolant heats the workings of the valve, it closes. As it cools, it opens. Thats how it works.

I agree that its not needed, and I agree that its uneeded complication, but thats how its done.

 

[sweet97]

they ran it thru to allow the fiav to work. As the coolant heats the workings of the valve, it closes. As it cools, it opens. Thats how it works.

I agree that its not needed, and I agree that its uneeded complication, but thats how its done.

It must be needed in the North country in the winter! I had mine disconnected when I had the TB reworked by...guy named Jon, rebuilt it and opened it up to a true/full 2.5" or 63.5mm. Ran OK in summer and when spring came around it idles poorly until I hooked the lines back. Mark
PS: It is a wax pellet inside that expands with the coolant passing through which lowers the idle when the motor reaches op. temp. Cold the pellet shrinks and lets more air in to raise the idle when cold. just leave it alone as it is best that way.