So i made my own GMMG exhaust and deleted the cats fro my SW ORY pipe, put on O2 sims, EGR codes now. I know its because of the lack of backpressure, but i was wondering if i made another exhaust with a spintech chambered muffler into side exits, would that give it enough backpressure to operate? Or does it need the cats. I don't feel like paying for it to be tuned out right now, and nobody around here (NE OHIO) can tune that i know of.

 

Madz28 was able to tune the PCM for me where the EGR worked around the loss of backpressure but did not remove the code completely. It would probably be the same cost as if you were to buy an additional muffler and have it installed.

 

I have about 10+ different mufflers and prototypes from different manufacturers in my garage, I make custom exhausts on the side so it wouldn't cost me anything to make another exhaust, but it looks like im gonna have to find a tuner then and just live with the code for now. It only seems to happen on the freeway in 6th gear cruisin. Thanks.

 

Even adding another muffler may not necessarily prevent the EGR code. I added a pair of cats into my ORY pipe and I thought that would help alleviate my EGR flow problem, but it did not. The tune, however, took care of it. Also, if you get a full tune from him, it will help your car not only run better but also add some power as well.

 

egr only works durring crusing conditions, so that explains your problem in 6th gear. usually your exhaust back pressure differences will not make any difference to the egr at crusing speeds, since there is very little engine load. don't rule your egr as the full problem. keep this in mind...if you are getting other emissions codes or faults, the egr system will shut itself down since it does not want to recirculate bad exhaust gases back into the engine. even a excessively rich short or long term fuel trim can cause the egr system to shut down to prevent itself from being damaged. Catalyst effeciency problems are famous for causing other emissions components to shut down and safe guard themselves. make your your o2 simms are working by checking it with a scan tool. if you can get ahold of a scan tool, it will help you find the answer. your catalyst monitoring O2 should normally switch at a lower voltage that your upstream o2's. maybe 100-400mv. over 400 mv indicating rich and under 150 or so indicating lean. if your simms are not giving proper voltage feedback, it could be richening the short term fuel trim, which you can see by comparing its percentages to the long term fuel trim percentages. you don't want to see over 5% to the positive side in a case like this.

 

the simms are working, there are no other codes thrown except the egr fault and insufficient flow. I'm probably gonna get a full tuning package by madtuner.com in the next month and disable the EGR code but leave AIR on there and disable the rear O2s as well (but still keep the sims on there since they are hooked up). I still have to get E-checked every 2 years and can swap in my randomtech cats when i want to, but im wondering if the disabled codes will show the 2 systems not ready, and i wonder if i'll still pass.

 

Call your emissions center and find out what the number of "not ready" statuses you are allowed. That is what I did when I was unsure.

 

Another vote for MadZ28. THey did my buddy's LT1 TA.. THat car pulls like crazy now!

 

Anyone have any experience with the JET DST harware? I found one on ebay for $375, it says new, but wouldn't it be VIN locked to a certain car, or am I wrong here. I think it may be worth shelling out the money upfront to have the ability to tune and retune and retune when i eventually get into major mods like cam swap, etc.