Raceghost

iTrader: (4)

Hello all,

Looking for anyone who has actually tuned EGR tables. I am still running EGR, and would prefer to run it for fuel mileage. I have read several post in places that suggest you increase the timing in the EGR areas, and or increase the fuel in those areas. It wasn't clear if it actually worked. Surprisingly enough, there is no info on the net here or there, with anyone who suggest how to tune it.

Can someone please chime in, with any type of suggestions on tuning this. I know how to disable it in the ECU, but again, I am trying to run it and tune it. Please point me in the right direction if you can.

Thanks in advance,

Raceghost

iTrader: (4)

Bump to the top.

edsct9a

iTrader: (5)

I've been messing with the EGR. I currently have a block set to 5 from 1750-3000 and I think loads 30-70, can't remember. I just moved it to this so can't say much on the mileage. Before it was from 1500-2500, believe, and on the highway I'm around 3k so it wasn't helping there. I was getting 17mpg on e85 highway cruising.

Raceghost

iTrader: (4)

The 94170715 Map tephra seven, with tables rescaled to match ignition tables, it is a block ranging from 2 to 8 in ignition advancement, from 1500 to 4000 RPM, and 30 Load to 80 Load. Do you think we need to remove timing here, or increase it? Do we need to enrich the fuel table here, cuz its in the cruise area's. Enrichment seems to defeat the purpose.

edsct9a

iTrader: (5)

I'm on 8859 and stock doesn't go up to 4K it stops around 2500 I think. To gain mpg you would have to increase it but up to a certain point. What I did was set the stock block and adjusted all the numbers to 5 degrees. All I really care about is my highway cruising since it's the only time I can really get the highest mpg and have a pretty heavy foot on the streets. Unfortunately the stock block that is advanced in the EGR table is not in the range of my highway cruising. I moved it up to the 3k range but I had bad luck yesterday and my ethanol content dropped when I fueled up and made my car run like ****, not sure if the EGR had anything to do with it as well. When you say enrichment which table are you talking about? The only one I have is accel enrichment. I think the best thing to do is get on the highway, get up to the speed/rpm you cruise at and log to see which load blocks are being used and adjust accordingly. From what I've read your vaccuum should increase as the car becomes more efficient but there's a point where adding timing won't have any effect and probably cause some knock.

Raceghost

iTrader: (4)

Difference between and 8 rom and a 9 rom. The 8's had more sections like I was saying. It is a block ranging from 2 to 8 in ignition advancement, from 1500 to 4000 RPM, and 30 Load to 80 Load. Am I saying it correctly referencing ignition advancement. The higher the number positive, the more advanced it is?

This is kind of confusing. What were your stock numbers respectively? Mine go as high as +8 degrees of timing. So it sounds like you removed timing from the EGR table? Also, when you tune for aftermarket parts, you tend to remove timing from the standard ignition table as well.

Had this issue for years, started right after I did larger cams. I don't think it is an EGR issue, as recently I have been doing some other adjustments in tuning, and have not touched EGR except to scale the tables respectively to the standard ignition tables for RPM and Load axis's, not touching the actual timing advancement within yet, and my issue has gotten better. It doesn't dip as much when fueling now.

I meant enrichment as to the main fuel table. But like I said, its in the closed loop range, and making the car richer, uses more gas, thus defeating the purpose of EGR, you won't gain MPG this way I don't think.

I have done this. I cruise between 70 and 80 load respectively up to 80 mph. I have a bigger issue during acceleration between 3k to 4k, I get a couple accounts of knock, randomly, due to EGR advancing timing during light acceleration. Its after the engine is fully warm, and after I have driven it around for a few. Then it knocks a couple of times like I said, suggesting the EGR is finally being utilized, and causing a timing issue. AFR's don't seem to be off...

Thanks again. Lets keep working on this. It has been a topic throughout the times.

Raceghost

iTrader: (4)

Just bringing this back up. Worthy of note, the guy that tuned my car pig rich, which is another topic on here, left EGR on as well as Lean spool. Just notating, on his excessively rich map, I get no knock in the EGR area of the maps. The minute I tune my Injectors, knock reappears in the 3000 rpm range, inconsistency, check logs, and it is directly related to EGR. So Overly rich conditions in that area must cool the EGR advance in relation to EGT recirculation, as well as give it enough fuel to run the timing that is also advanced by the EGR. Just my interpretation of what I am reading from logs.

edsct9a

iTrader: (5)

I've been meaning to reply but I work weekends so busy Fri-Mon. Are you running closed or open loop in the cruise area? I'll address the other post shortly.

Raceghost

iTrader: (4)

Closed loop.

edsct9a

iTrader: (5)

Yes, that is correct.

The stock 88590015 table has advancement from rpm 1500-2500 and load 30-60 ranging from 2-7*. Only two blocks go higher then 5* so didnt remove much and to me it seems more consistent changing the whole block to a single number. When I was tuning 91 I didnt mess with the timing or fuel under load 100. On E85 the timing is advanced in this area but the fuel only changed following the 14.7 blocks since it is a lot leaner transitioning into the boost loads.

As far as I know changing the low load areas wont do much unless you run open loop all the time.

I get knock in the same fashion but its so inconsistent I dont really care about it.

Raceghost

iTrader: (4)

My only real concern, is it every now and then knocks above 3 counts. And if I am approaching warp speed, it throws the whole boost pull off. SO I got to do a little something to get it out of that area.

Any suggestions?

ace33joe

iTrader: (2)

I think EGR is there for two reasons:

1. Less NOx emision - lowering the combustion chamber temp by injecting "recirculated" exhaust gas
2. Better cruise MPG - Since chamber temp is lowered, you can advance a few degree timing

For better mileage you can do full open loop fueling and "lean burn" to 15.x:1 AFR

If you keep it to 14.7:1 AFR at closed loop, you can play with EGR duty cycle (may change how much exhaust gas is recirculated) and added timing (depending on your fuel, you may add a bit more without causing knock).

Although I did not perform any experiment with those two tables, since I use EVO only for fun / track days, so I disabled EGR to keep the intake manifold clean.