hi i dont know if it is better to remove or keep the egr on the 3800 im not looking for answer like i did it because everyone did it . im looking for a good theory why keep it or why not . in my mind the function of egr is to cool the combustion chamber to lower the nox but does it can help for the kr ( im putting some performance parts like s1x cam ported heads pulley intercooler headers .....)??????? many thanks for your help
Removing the EGR will make things cleaner on the inside of the super charger and throttle body and some like the look of it missing on the out side which i can see. removing it means the PCM needs to be programmed to match so no engine codes from it and will cost you a little on the fuel mileage. Keeping it will dirty up the inside and may not look the best sitting there but will save you some fuel and will keep the emissions guys off you back side which from what I have been told Quebec is bad for enough already.
yes, running egr makes engine run slightly cooler (who would of thought) thus reducing KR. I'm also in the midst of a 3800 series 2 sc swap and I'm keeping egr from all I have read.
[This message has been edited by TbirdMarc (edited 02-19-2014).]
The EGR valve only works at part throttle on any engine, so any affect it would have on KR would only be during part throttle operation and it would have no impact on full throttle performance (or KR at WOT) at all.
That having been said, 3800 SC engines only have an 8.5:1 compression ratio and you should be running premium unleaded fuel at all times in one of these engines anyway (so you don't hurt it when giving it boost) - therefore there is virtually no risk of any KR or a hot running engine due to the EGR being eliminated - if you so choose to delete it from your 3800 SC engine.
Since it doesn't hurt performance, there's really no reason to remove it from your 3800 SC engine if it is already on there and in working condition. I've seen more guys introduce problems by deleing the EGR because of the leaks they create by not properly sealing the EGR system holes in the intake and exhaust. I've heard guys claim that having a working EGR valve coats everything in the intake (including the supercharger roots) with a black carbon residue after long-term use, but I've never seen any evidence to suggest this small amount of carbon buildup hurts performance one but. It is more of a cosmetic concern I believe. The truth of the matter is you will still get a carbon buildup inside the intake of any engine even if it has no EGR and no PCV system due to the fuel vapors condensing on the intake walls after you shut the engine off.
So my advice for anyone is if you already have a working EGR system on any engine you are using, there are going to be virtually no benefits to deleting it other than cleaning up the appearance of the engine. If you are building a Turbo setup with a different intake that would require you to go thru some pains of getting the EGR system to work, then it probably won't be worth your efforts to install it (due to the low compression ratios turbo engines generally run and the less benefits of having a working EGR would bring to this configuration).
The job of the EGR is to introduce inert combustion gasses into the cylinder to help cool combustion (reducing NOx emissions) during normal part throttle operation. On some applications, having a working EGR valve may result in a miniscule increase in fuel economy. Engines with low compression ratios, and even high compression engines with big overlap camshafts, will have little benefit of having a working EGR valve installed since normal part throttle combustion pressures (and temps) will be relatively low anyway.
------------------ OVERKILL IS UNDERRATED Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com
[This message has been edited by Darth Fiero (edited 02-20-2014).]
If you have ever seen the intake manifold of an engine with an EGR valve? It's full of carbon sludge that is one of the hardest substances known. If you are concerned about higher combustion temperatures you can just add an intercooler.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
If you have ever seen the intake manifold of an engine with an EGR valve? It's full of carbon sludge that is one of the hardest substances known. If you are concerned about higher combustion temperatures you can just add an intercooler.
I am not concerned about high part throttle combustion temps.
I do like the idea of better fuel efficiency on long road trips. I need to try to find some factual data on what the MPH gain is for a 3800 SC in something light like the Fiero. I am inclined to believe Ryan is correct - very very little...
Speaking of Darth Fiero - I have not seen him on here in a while. Anyone heard from him recently?
Anyone have a number based on some testing or other facts?
[This message has been edited by DimeMachine (edited 11-27-2020).]
Cylinder pressure (vertical) is plotted as a function of cylinder volume (volume changes as the piston goes up and down).
To impart useful work on the crankshaft, we desire high cylinder pressure as the volume is increasing (piston going down), and low cylinder pressure as the volume is decreasing (piston going up).
To evaluate the total work, we measure the area enclosed by the indicator diagram. If the indicator diagram is drawn on grid paper, you can count the squares... This is straightforward with a 2-stroke steam cycle (as can be seen in the wikipedia article).
The power loop is counted as positive work, while the pumping loop is counted as negative work.
So what the article is saying, is that during the intake stroke, the cylinder pressure can be higher with EGR, reducing negative work in the pumping loop.
For my Fiero project, I don't like circulating dirt through my intake, nor the engine bay clutter, not to mention that it's yet another output to have to tune (more complexity) on the computer.
[This message has been edited by pmbrunelle (edited 11-28-2020).]
Speaking of Darth Fiero - I have not seen him on here in a while. Anyone heard from him recently?
Anyone have a number based on some testing or other facts?
I haven't seen or heard from him since he ripped me off on a trade deal. I delivered product and he delivered nothing in return. My messages were ignored. If you want the full story PM me. The guy is a thief.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
