EGR Delet on 89 SC
- Thread starter boostwhat
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thebigslide
Registered User
How to delete EGR
You <I>can</I> machine a blockoff plate and replace your EGR valve with the plate and then use a OpAmp to trap the EGR valve signal and feed it back to the position sensor harness, but it's a lot of work. I did it on a foxbody Cougar so I could swap to a different intake that didn't have provisions for an EGR valve, but it was more trouble than it was worth for the paltry 4HP or so I picked up from the manifold.
How come you want to remove the EGR?
Yes, but why? EGR actually GIVES you power at cruise speed and is totally disabled at WOT. EGR also increases the longevity of your plugs and gives you throttle response by keeping the air velicoty up at part throttle.boostwhat said:
You <I>can</I> machine a blockoff plate and replace your EGR valve with the plate and then use a OpAmp to trap the EGR valve signal and feed it back to the position sensor harness, but it's a lot of work. I did it on a foxbody Cougar so I could swap to a different intake that didn't have provisions for an EGR valve, but it was more trouble than it was worth for the paltry 4HP or so I picked up from the manifold.
How come you want to remove the EGR?
racebronco2
Registered User
You <I>can</I> machine a blockoff plate and replace your EGR valve with the plate and then use a OpAmp to trap the EGR valve signal and feed it back to the position sensor harness, but it's a lot of work. what is a opamp ... i am swapping my 4.0 ranger for a sc computer because i have the sc blower on my 4.0 so i need to do the same thing
Simple...I did it on my 90 & 94SC's...You don't have to machine the plate, it is much simpler than that...Just a piece of flat iron, or whatever ya got....There is no real pressure or heat so it don't matter.
Plug the EXH. port on the manifold...Leave the electronix plugged in so you don't get the CE light and poof you are done...
The biggest reason I got rid of the system is because it was always in the way, and it was a PIA to troublshoot when you got codes...Most of the BIG Pony guys have NO EGR so I doubt you are gonna be left at the light because you have no EGR system...LOL...
Brad
Plug the EXH. port on the manifold...Leave the electronix plugged in so you don't get the CE light and poof you are done...
The biggest reason I got rid of the system is because it was always in the way, and it was a PIA to troublshoot when you got codes...Most of the BIG Pony guys have NO EGR so I doubt you are gonna be left at the light because you have no EGR system...LOL...
Brad
thebigslide
Registered User
What is an OpAmp
an Op Amp or Operation Amplifies takes and input signal and gives an output signal of a scaled down or up level... Your EGR system checks the position of the valve. The purpose of the OpAmp is to take the signal going to the valve, scale it down and feed it back to the computer, tricking it into thinking the EGR is still hooked up. I can send you a schematic, if you like for how to wire a $5 OpAmp from radio shack in the circuit. It saves having the valve and crap dangling uglily under the hood. If you're going to remove the EGR, you might as well make it look trick, not ghetto. Please don't user a gross scrap piece of iron as was suggested, use a nice shiny plate, and RTV it on there to prevent any leaks as there IS pressure behind the valve and it does get warm (as does the rest of the intake).
an Op Amp or Operation Amplifies takes and input signal and gives an output signal of a scaled down or up level... Your EGR system checks the position of the valve. The purpose of the OpAmp is to take the signal going to the valve, scale it down and feed it back to the computer, tricking it into thinking the EGR is still hooked up. I can send you a schematic, if you like for how to wire a $5 OpAmp from radio shack in the circuit. It saves having the valve and crap dangling uglily under the hood. If you're going to remove the EGR, you might as well make it look trick, not ghetto. Please don't user a gross scrap piece of iron as was suggested, use a nice shiny plate, and RTV it on there to prevent any leaks as there IS pressure behind the valve and it does get warm (as does the rest of the intake).
thebigslide
Registered User
Sorry for the Typo, the device is called an Operational Amplifier.
thebigslide
Registered User
cudaz101 said:
I knew I'd eat that comment. Though your machine is much nicer looking than mine, inside and out, believe you me, a shiny blockoff plate and lack of an 'extra' wire harness would pretty it up further. People ask you about the plate (mine's billet aluminum) and you get to tell them it's a custom engine mod that no one else has.
I'd rather have an engine bay as clean as yours and fancy rims over a billet blockoff plate any day, tho, cuda. What happened to you antenna, tho?
racecougar
Registered User
Here's the EGR delete plate that I made for my 4.6L DOHC in my 90 XR7. It's 1" billet aluminum.
Some SC's came without EGR and had a factory EGR delete plate.
-Rod
Some SC's came without EGR and had a factory EGR delete plate.
-Rod
thebigslide said:
As an emmissions control device, how can the EGR 1) give you power by replacing a fuel/air mixture with inert gases and 2) improve throttle response and plug life (considerably). I have always heard that the EGR causes a slight lag in throttle. As far as people saying deleting the EGR will decrease MPG, I say as long as A/F ratio is maintained (not so easy on OBDII) it should not change, or at least not decrease. These are just theories (I am no combustion engine expert) or supposed facts from readings or statements from techs, but I have not seen them disproved yet with any hard facts.
thebigslide
Registered User
talon660 said:
EGR works by adding cooler exhaust gasses (relatively, at part throttle, exhaust gasses are considered cool) to the combustion mixture. They are heated by the combustion and aid in adding pressure to the combustion chamber during the power stroke. That's how it adds [free] power at part throttle. EGR increases plug life by quenching the plugs with cooler-than-combustion-temp. gasses and keeping them operating at a cooler temperature than otherwise. Throttle response is increased by EGR because the air velocity in the intake runner of the cylinder head is kept up at part throttle conditions. Cruising MPG will decrease slightly after deleting EGR because there is less combustion pressure due to these cooler gasses not being heated by the combustion process. The effect of EGR is similar to the effect of H2O injection used in some industrial and older diesel engines such as the infamous GMC XV71 series.
Any further questions? I'll be a certified aerospace engineer in a year and have been an apprentice mechanic for 3 years now. I hope to get a job with Ford developing engines and cylinder heads.
XR7 Dave
Registered User
thebigslide said:
Some good discussion, however a few things you may be interested to know. At part throttle cruise my EGT's hover around 1400 degrees and under WOT they drop to about 1300. So part throttle exhaust is not cooler than full throttle. Rather what is happening with EGR is that the exhaust gases are inert (IE, they won't burn, and hence they dilute the incoming charge without leaning the mixture. If you were to just add air, that would dilute the mixture as well, but it would also lean out the motor. Leaning out the motor is not a bad thing under cruise conditions, it's just that your converters do not opperate well at anything other than 14.7:1 AF ratio. Not only that, but when you lean out the mixture you increase NOx emissions which is a no-no with the EPA. Hence the idea of using burnt exhaust to dilute the charge thus reducing your combustion temperature and allowing you to run more ignition timing under part loads.
Removing the EGR will result in too much timing under some circumstances and can lead to pre-ignition. Proper tuning will compensate for this and result in better mileage and better power w/o EGR.
I'm no expert so there may be some errors in what I have said. :/
thebigslide
Registered User
Interesting that your EGT goes UP at part throttle. This isn't typical of a NA engine, although it's possible forced induction engine behave differently in this respect. I'll have to have a look into that. You've piqued my interest, Dave. What sort of sensor are you using? Also, was this reading under load?
Also, does your car have cats and an AIR pump? This could give you false readings if your sensor is located in the AIR pump's airstream.
Also, does your car have cats and an AIR pump? This could give you false readings if your sensor is located in the AIR pump's airstream.
XR7 Dave
Registered User
Temps rise under part load due to a leaner mixture. This is normal. I am using an exhaust probe pyrometer mounted high in a primary header pipe. There are no polution devices on the car to throw off readings. I've had the gauge in the car for a long time and continuously monitor (with a dash mounted gauge) temps as I drive under all sorts of conditions from idle to cruise to WOT.thebigslide said:
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thebigslide
Registered User
cool... I want one.
thebigslide
Registered User
XR7 Dave said:
You're totally right, Dave. I just checked the Chitons... the exhaust gasses reintroduced through the EGR circuit are cooled prior to recombination with the incoming intake charge by that the flex-looking tubing; it acts as a heatsink for the EGR gasses, cooling them before they mix in with the intake charge. 5.0s cool the EGR gasses with that spacer through which coolant runs.
Chiltons???
The flex tube that does all this cooling was not used on my 94SC, so I would doubt that the said flex tube did much in the way of cause and effect in the system since it was replaced with a smooth mandrel bent tube in the 94 and most likley the 95 as well. I did have a flex style tube on my 90SC when I deleted it.
BTW...I mentioned that you or anyone could use flat iron to get the job done. It does not take a genius to figure out that he or she could use aluminum as well... Just plain and simple....Make your own, use whatever you have that will work, or be picky and do something custom...Who really cares???
Also...I mentioned to leave the electronix plugged in to keep from having a CE light since that would be the next question after the deletion of the system...These are ALL inquiries that have had heavy traffic among our boards over the years. Yea use a chip or a tuner and correct it that way if you have an extra few hundred bux layin' around...
If the EGR system was such a success then why did it come and go with our cars? There is alotta grey in the theorys' that I have read on it. IMO "and it is not one that has much research behind it" the system is a POS, it is in the way, it is too burried to properly troublshoot...Basically just replace every part of the system when it pops a code because 9 times outta 10 the first or second part you change is not gonna fix it....Too much trouble for the unproven return...
"TheBigSlide" If you are gonna work for FORD you better buy some better books...Not to discredit anything you have contributed technically.
Brad
The flex tube that does all this cooling was not used on my 94SC, so I would doubt that the said flex tube did much in the way of cause and effect in the system since it was replaced with a smooth mandrel bent tube in the 94 and most likley the 95 as well. I did have a flex style tube on my 90SC when I deleted it.
BTW...I mentioned that you or anyone could use flat iron to get the job done. It does not take a genius to figure out that he or she could use aluminum as well... Just plain and simple....Make your own, use whatever you have that will work, or be picky and do something custom...Who really cares???
Also...I mentioned to leave the electronix plugged in to keep from having a CE light since that would be the next question after the deletion of the system...These are ALL inquiries that have had heavy traffic among our boards over the years. Yea use a chip or a tuner and correct it that way if you have an extra few hundred bux layin' around...
If the EGR system was such a success then why did it come and go with our cars? There is alotta grey in the theorys' that I have read on it. IMO "and it is not one that has much research behind it" the system is a POS, it is in the way, it is too burried to properly troublshoot...Basically just replace every part of the system when it pops a code because 9 times outta 10 the first or second part you change is not gonna fix it....Too much trouble for the unproven return...
"TheBigSlide" If you are gonna work for FORD you better buy some better books...Not to discredit anything you have contributed technically.
Brad
XR7 Dave
Registered User
Cooling the exhaust is not an issue. The volume of exhaust is relatively small and it cools as soon as it mixes with the incoming air if it hasn't already. However, it does still introduce comperatively hot air into the intake and so more HP may be able to be extracted if that added heat is not present.thebigslide said:
Oh, and remember, heat =/ temperature. My exhaust has a lot of temperature under cruise conditions but not a lot of heat.
For some better information on Ford and EGR you should pick up a copy of the book "Ford High Performance Fuel Injection Systems" by Charles Probst. Good reading. Book.