egr question

[bonnieclyde100]

have any of you guys ever added an egr valve to an engine and intake that was never designed for one and if you did how did you do it ? pictures would be great. i am having trouble with knock counts being high like 3900 counts in a 25 minute drive home from work . the closer i get to the 128 blm the more knock counts i get. if i have my blm at 120 or less i dont seem to get any knock retard . if i can add an egr i would get less knock and be able to get a little better miles per gallon. will probably run a little cooler especially when towing.

[steveo]

sure you can add one, but i wouldn't. there's very little actual benefit to an egr.

are you getting knock in cruising range or power enrichment? it sounds like your power enrichment AFR is too lean to me. if it's knocking in cruise range, you probably just have too much timing advance.

also fyi 3900 counts isn't necessarily a lot of knock, when a knock event happens, it's typical that it increases hundreds or even thousands of counts all at once just for 'a few knocks'.

[bonnieclyde100]

im geting knock retard all over the map .alot in the cruising range that wasnt there when the blm was 120 or less.as far as timing i started with a stock map and went down and i should have been able to go up a little withe cam i have. its not to agressive but a little more than stock. iwould like to add an egr but my intake doesnt have a spot for one and i dont want to buy a new intake.

sure you can add one, but i wouldn't. there's very little actual benefit to an egr.

are you getting knock in cruising range or power enrichment? it sounds like your power enrichment AFR is too lean to me. if it's knocking in cruise range, you probably just have too much timing advance.

also fyi 3900 counts isn't necessarily a lot of knock, when a knock event happens, it's typical that it increases hundreds or even thousands of counts all at once just for 'a few knocks'.

[bonnieclyde100]

i thought about what you said so i looked at my data recording frame per frame and it would retard right after my acceleratoin enrichment would go from active to inactive and i have a four barrel tbi so i think i need to add some enrichment time to the AE vs. TPS differance because i need only half the throttle to get the same acceleration.

sure you can add one, but i wouldn't. there's very little actual benefit to an egr.

are you getting knock in cruising range or power enrichment? it sounds like your power enrichment AFR is too lean to me. if it's knocking in cruise range, you probably just have too much timing advance.

also fyi 3900 counts isn't necessarily a lot of knock, when a knock event happens, it's typical that it increases hundreds or even thousands of counts all at once just for 'a few knocks'.

[steveo]

im geting knock retard all over the map .alot in the cruising range that wasnt there when the blm was 120 or less.as far as timing i started with a stock map and went down and i should have been able to go up a little withe cam i have. its not to agressive but a little more than stock.

you'll find as the size of a cam goes up, sometimes timing advance requirements go down. also as your cam gets larger your entire operating range shifts on the map axis of the timing table since it's making less vacuum. i'd revisit your timing table and increase power enrichment fueling a bit.

[bonnieclyde100]

which table and how much TPS for fast PE vs. RPM , TPS for PE vs. RPM , PE AFR vs. RPM , fast PE entry delay reduction vs. RPM , PE TPS differance vs. BARO ?

you'll find as the size of a cam goes up, sometimes timing advance requirements go down. also as your cam gets larger your entire operating range shifts on the map axis of the timing table since it's making less vacuum. i'd revisit your timing table and increase power enrichment fueling a bit.

[bonnieclyde100]

here is my stuff if anyone wants to look and give advise. the last one is the recording.

[bonnieclyde100]

i was looking at my timing advance and somehow i managed to advance it way above stock so i put it back to stock and i will start from there. the only this is the stock timing curve stops at 30 degrees ands i think it could handle more than that. it is an $OD BJYL bin.

[steveo]

i had a quick peek;

i wouldn't think that timing table you posted would be knocking BUT: you always have to remember that the stock timing tables might have spark adders from all sorts of other tables and calculations.

for example if you still have EGR code running, it might be adding spark advance for that even if you aren't aware of it (i notice your egr spark advance table is not zeroed out, how did you disable the egr?)

$0D has PE spark added in a seperate table.

this all adds on top of your base distributor timing, which should be zero, according to your calibration, so i hope it is.

as far as your PE AFR goes, it's mostly 12.6:1, which is pretty safe, if your airflow metering is correct, which it might not be. if removing fuel causes more detonation in PE, i'd tend to assume that a bit more fuel is masking spark knock. extra fuel cools the combustion chamber a lot.

do remember when going over your spark tables, more isn't always better, just because you think an engine should be able to handle more spark doesn't mean that it needs it. you just want to reach peak vacuum at cruising and peak power without knock in those high MAP cells.

[Fast355]

No way would I add an EGR to something that didn't have it. No need for that carbon recirculating, engine destroying unit on your intake. Having an EGR is more of a nightmare than it is worth.

Maybe the 02 constants are running the engine too lean at cruise. Cruise timing is very dependent on combustion chamber, cam profile, vehicle weight, transmission and differential gearing, and tire size. An undergeared, unaerodynamic vehicle with an overdrive transmission is not going to want nearly the timing that a sleek, lightweight, overgeared, non overdrive setup will want. My old 305 in the Corvette likes 48-52* of timing at cruise, cruising down the road at 3,000 rpm @ 85 mph.

[ony]

are you running 93 fuel? I am having the same problem on a 4.3 vortec it started picking up crazy knock counts droped the timming by 8 degrezz still knocked ,I changed the modgul in the dist., no knocks for 2 days then started knocking again. bought some 93 while ago coming home 470 knocks then it went back to less knocks than normal. not going to say much till I see what it does tomorrow. this is a stock engine an tune except for the ve table. the price of gas went down to 285 a gallon here and I think so did the quality of it.

[bonnieclyde100]

i burn 87 but i droped the timing down to stock about 6-8 degrees and have not had a knock since. they are switching over to winter gas which is not as good as summer gas less power less mileage

are you running 93 fuel? I am having the same problem on a 4.3 vortec it started picking up crazy knock counts droped the timming by 8 degrezz still knocked ,I changed the modgul in the dist., no knocks for 2 days then started knocking again. bought some 93 while ago coming home 470 knocks then it went back to less knocks than normal. not going to say much till I see what it does tomorrow. this is a stock engine an tune except for the ve table. the price of gas went down to 285 a gallon here and I think so did the quality of it.

[bonnieclyde100]

the onlky thing i dont like now is im only running between 18-24 degrees of timing cruising the highway at 75 miles per hour 2500rpm. not sure if thats good or bad

[Fast355]

the onlky thing i dont like now is im only running between 18-24 degrees of timing cruising the highway at 75 miles per hour 2500rpm. not sure if thats good or bad

Is your engine pushing a motorhome?

[bonnieclyde100]

no a 1969 chevy truck .

Is your engine pushing a motorhome?