North American Turbocoupe Organization



84 TC Can i remove egr valve?
svo_thunderchicken Offline
Senior Member
#1
I was wandering sense we dont have emmisions in my state, will it hurt anything to remove the egr system and block it off? How will it effect performance?
84 TC Silver 5 speed - PE EEC, Big Vam, RR cam, 35lb injectors, E6 swap, T3 60 Trim, 87-88 intercooler and hood, BOV, K&N Cone Filter *under constrution*
http://www.cardomain.com/ride/2298891/1

87 TC Black 5 Speed - Stock IHI, BCS Bypassed
http://www.cardomain.com/ride/2390431
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trashline Offline
Posting Freak
#2
well you do know what it does correct? it takes the exhuast and runs it back into the intake for the motor to burn. what is in exhuast? nasty crap. If you block it off it wont give you any performance change but it will keep the intake cleaner.but you could probably expect to use the cat up quicker.

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1966 mustang
1988 tbird

found this reading the archives good for a laugh
quote:
--------------------------------------------------------------------------------
Originally posted by: fordprefect

Mine sounds like twenty crickets on meth!
Brian

www.BCPCustom.com

06 Cobalt SS
66 mustang 289 C4 handfully modded

Stingers IC install and tbird photos
http://community.webshots.com/user/trashline
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Joe F Offline
Posting Freak
#3
No offense, but you need to do a little research before making blind statements like that. The EGR actually does perform a useful function or two, and the stratagies programmed into the ECU take it into account.

Also, only under certain conditions is a _small_, metered amount of exhaust injected into the intake, which lowers the amount of O2 in the fuel/air charge, thereby lowering fuel requirements and also reducing NO emmissions by reducing the burn temperature.

From everything I've read, you will most likely see a drop in fuel mileage by removing the EGR. Besides which the EGR is only active during low-load cruise, not during idle or at WOT operation.

Several past discussions on this, and I remember posting a link or two to _real_ good explanations on the subject.

Just my 2¢ worth, not trying to bust your chops. [Image: biggrin.gif]

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Joe F.
JR's Aerie - Our 3 TC's
JR's Place - My '87 Turbocoupe
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trashline Offline
Posting Freak
#4
so what was false about the statement i made? except for the performance change? and since your statement says "only under certain conditions is a _small_, metered amount" what is the full effect of removing it loosing a half a mile a gallon? my statement is right on the money with the function of the EGR. I didnt go into super detail b/c I didnt find the need.

also Not trying to be a jerk off just defneding myself and you can understand that.

now my questions... what effect does the ECU have on the EGR? the EGR opens with the vacuum created at crusing speeds as you stated how does the ECU change that? minimizing the amount of fuel? as the pc knows the egr is there or suppoed to be there. say you remove it the ECU doesnt realize it and will continue to lower fuel output. I dont remember seeing a sensor of some sort on the egr setup so I could be wrong.

and svothunderchicken I apalogize for miss leading you if you found my statements missleading and blind.

------------------
1966 mustang
1988 tbird

found this reading the archives good for a laugh
quote:
--------------------------------------------------------------------------------
Originally posted by: fordprefect

Mine sounds like twenty crickets on meth!
Brian

www.BCPCustom.com

06 Cobalt SS
66 mustang 289 C4 handfully modded

Stingers IC install and tbird photos
http://community.webshots.com/user/trashline
Reply

svo_thunderchicken Offline
Senior Member
#5
My understanding is that the ecu is capible of making changes on the fly based on other sensors and the o2, if the egr does change somthing, shouldnt it correct itself?
84 TC Silver 5 speed - PE EEC, Big Vam, RR cam, 35lb injectors, E6 swap, T3 60 Trim, 87-88 intercooler and hood, BOV, K&N Cone Filter *under constrution*
http://www.cardomain.com/ride/2298891/1

87 TC Black 5 Speed - Stock IHI, BCS Bypassed
http://www.cardomain.com/ride/2390431
Reply

Jeff K Offline
Administrator
#6
First of all, I agree 100% with what Joe said.

When EEC thinks EGR flow is present, it advances the timing to compensate for the decreased burn rate. Without EGR there, you may get light throttle detonation. Sure, you could drop base timing to compensate, but that will hurt performance across the board.

EGR also helps gas mileage since it requires more throttle opening at crusing speeds to compensate for less power being produced due to the charge dilution with inert gasses. This means lower intake vacuum (i.e., closer to atmospheric pressure) which reduces pumping losses in the motor, which increases gas mileage.

As far a gunking up the intake, yes, to a VERY limited extent. You might have to clean a little but of crud out of the intake every 100K miles or so.

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Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 23 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 04 Taurus Duratec (wifes car) // 91 Topaz (daughters first car)
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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trashline Offline
Posting Freak
#7
Quote:Originally posted by Jeff K:
First of all, I agree 100% with what Joe said.

When EEC thinks EGR flow is present, it advances the timing to compensate for the decreased burn rate.

EGR also helps gas mileage since it requires more throttle opening at crusing speeds to compensate for less power being produced due to the charge dilution with inert gasses. This means lower intake vacuum (i.e., closer to atmospheric pressure) which reduces pumping losses in the motor, which increases gas mileage.


Im a bit confused, first It is pretty interesting that the EEC can adjust things tlike time b/c it thinks the EGR is working. I understand the effects of lower vacuum

now what I dont understand is how the EGR effects gas milage if removed. what gases are you talking about? in the "charge dilution" if the EGR is removed? there is no gases correct? or are you talking abotu the fuel and air mixture? it almost sounds like the EGR creates lower vacuum.



------------------
1966 mustang
1988 tbird

found this reading the archives good for a laugh
quote:
--------------------------------------------------------------------------------
Originally posted by: fordprefect

Mine sounds like twenty crickets on meth!
Brian

www.BCPCustom.com

06 Cobalt SS
66 mustang 289 C4 handfully modded

Stingers IC install and tbird photos
http://community.webshots.com/user/trashline
Reply

Joe F Offline
Posting Freak
#8
Trashline - Take a deep breath and reread what I posted; I did not say you were wrong, just implied that you wern't telling the whole story. Probably a poor choice of words on my part, sorry about that. However, when you make blanket recommendations (is that better?) like yours in the post, you're also implying that there will be no negative consequences if those recommendations are implemented. In this case there can be, hence my reply to your post.

Now to answer your questions: The EGR doesn't affect the ECU, rather the ECU controls the opening of the EGR valve. Therefore the ECU "knows" when the EGR valve is open, and also performs the tasks that Jeff presented. So, if you remove the EGR system, the ECU has no way of knowing that it is no longer present, and will still perform those other functions, with possible deleterious effects. Also, I think the MPG reduction would be more on the order of 2-3 MPG, not just 1/2 MPG. Of course that's just my opinion.

The "inert gasses" Jeff mentioned are the exhaust gasses that are injected into the intake; those gasses reduce the amount of fresh air being fed to the engine, thus the "charge dilution". Finally, since the A/F charge has been reduced, the engine produces less power, meaning that the throttle has to be depressed more to cruise at the same speed. Wider open throttle = lower vacuum, higher mileage resulting.

Sorry if my reply made you think you were being attacked; it was not meant that way. However, NATO is about good, reliable, and complete information about our cars, and in this case the info was not complete enough to let anyone make an informed decision.

Cheers!

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Joe F.
JR's Aerie - Our 3 TC's

[This message has been edited by JoeCool (edited 08-04-2005).]
JR's Place - My '87 Turbocoupe
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Jeff K Offline
Administrator
#9
Engines are air pumps, as you know. With high vacuum in the intake (nearly closed throttle), it takes energy for the piston to move down as it tries to suck air thru the nearly closed throttle plate. This is called a pumping loss. At WOT, there is virtually no pumping loss, as there is no vacuum in the intake. With EGR, the inert exhaust gasses in the cyl reduce the power produced by that cyl, requiring more throttle opening to make up for this. More throttle opening = lower engine vacuum (say 10" Hg with EGR flow versus 14" Hg without EGR flow) to produce the same power putput from the motor to hold a given speed. There are less pumping losses at 10" Hg than 14" Hg, therefore less power (which comes from burning fuel) wasted, = slightly better fuel mileage. This is a greatly oversimplified version of what goes on. You need to have a pretty good understanding of thermodynamics and fluid mechanics to really understand what is going on.


------------------
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 23 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 04 Taurus Duratec (wifes car) // 91 Topaz (daughters first car)
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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Chuck W Offline
Posting Freak
#10
The short form svo-t is that if it's working.....leaving it alone. It's not hurting you performance-wise. [Image: wink.gif]

Until you can get into the ECU or swap to a stand-alone ECU to negate the EGR in the programming, you're taking out a part of a system that is designed to work together that is controlled by an ECU that knows just enough about what's going on and controlling to get itself into trouble. For the ECU, the EGR being there is a given....it's assumed that since it's required for federal emissions, it's not required to see if it's there and working, so it won't look for it or compensate for it. The EEC 4 is good, but not THAT good.

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83 TC Clone, 87 Ranger 2.3T, 84 XR7, 80 XR7, 86 XR4 AND 88 Scorpio
NATO Member
83 TC Clone, 80 Cougar XR-7, 85 Volvo 244 Turbo, AND 88 Scorpio
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