I recently went about remodeling my EGR valve. I tilted it back about 30 degrees and placed a plate over the intake area on the engine. The reason for doing this was to remove that pesky emissions control feature that robs horsepower. I didn't just unplug it because I didn't feel like staring at the service engine soon light. Anyway 2 questions, that power I think I feel, is it real or just imagined. And is there any foreseeable problems with doing this modification. Oh yeah Anyone hear about hypertech coming out with an ECU replacement for our 4.2's??

//John

 

Deleting the EGR valve is a fairly common modification. The upside is a cleaner/cooler intake charge and a significant reduction in carbon buildup in the intake. The downside is that you may experience spark-knock (pre-ignition) without changing your spark advance curve and will likely fail any emissions testing required by your state. Does it provide performance gains? Small gains have been seen in dyno testing supercharged 5.4 (Lightnings) with EGR delete so one could assume a similar few HP are seen win NA motors.

 

so until I purchase a programmer, it's probably best that I use either higher octane fuel or replace the valve for the time being. BTW correction on the hypertec ECU replacement I was mistaken It is the hyperpac from hypertech, and dang does this thing look pretty sweet. I hope they get around to getting this out for the 4.2 liter engines.

//John

 

If you don’t mind the extra expense, then it would probably be safer to use higher octane until you can reprogram your CPU via chip or flasher.

 

cool thanks for the info, I will decide at pump when i fill up, because the programmer is about a month out financially, that and I need to do some brake work, rough, but once it's done, it's done for a while.

//John

 

I got a MIL earlier in the day while driving around, so I figured I needed to perfrom some more modifications in order to trick out the dpfe sensor into thinking that everything was hunkey dorey (spelling). Well upon reading sigma's post on knock I decided to go down and check it out with the autotap tool. I didn't see any knock, but I did notice when I started the truck the MIL light went out. the codes were still present but no light. Insuffecient egr flow. I will have to run a log on the truck while driving to see how much knock I get, decide just how high of octane I need in order to prevent that issue. so anyway I am down here in my truck sweating like a pig just let you all know that this way of removing the egr valve might not fire the MIL light, or if it does, only for a short period of time. If it does come back on I will try to find a way to create vacuum at the oriface of the valve to simulate the intake vacuum. I just wish there was an electronic way to trip out the sensor. Anyway I got pics of the modification in my gallery, check it out.

//John

 

The EGR valve should only open during closed throttle deceleration when the throttle plate in the throttle body is closed. On acceleration there is low vacuum in the intake because the throttle plate is open. Therefore there is not enough vacuum to open the egr valve anyway. I am having trouble understanding why eliminating the egr would have much effect on power if it is operating normally. I also do not understand why the elimination of a source of hot gas into the intake would promote pinging or preignition. I would think it would have the opposite effect. I am not saying you guys are wrong, I am just adding a few thoughts for consideration.

 

Supposedly combustion temps will rise slightly as measured with EGT gages following the EGR delete. Some Lightning owners have experienced tip-in detonation. If I had to guess (and it’s only a guess) I would say the partially burnt exhaust gasses might slow the flame front during ignition. When you remove the gasses by deleting the EGR the intake mixture burns faster which raises combustion temperatures and increases the possibility for detonation

 

sigma, I believe you have hit that nail on the head, from what I understand the EGR system is designed to lower the exhaust gas tempeture. This is done by creating a dirty burn in the combustion chamber. The results of this lower tempeture combustion are more easily handled by your catalytic converters. Yet another usless emissions system that I would remove if given the chance to create enough back-pressure some other way. Anyway back to the point at hand, removing the EGR valve really wasn't meant to be a performance mod (or at least I didn't think so when I did it.) but to simply prolong the life of my engine and make the oil look even cleaner when I drained it after 2000 miles. That and it partially satisified my political dis-like for california.

//John