turboglenn
15+ Year Contributor
- 6,375
- 123
- Nov 5, 2007
-
RIpley,
West Virginia
He's reading a gasoline AFR the 12.5 is representative of what a gasoline mixture would be at the same lambda value since the AEM and most wide bands read lambda then do match conversion for display. If you read the chart that the AEM WB comes with then you will see that the 11:1 display is the same as if it were set to display ethanol values and would still be correct based on lambda voltage.. basically the mixtures it likes will represent themselves properly when displayed as gasoline and the 11:1 gas AFR is equal to the ratio that woulds be the same lambda value on ethanol. So he is reading right, just saying the wrong thing since all of us are use to just talking gas AFR's because there's no difference in the "area" of mixture you should be in for stoich and above and below
To the OP, do you have enough left over outputs to fire the COP sequentially so you can run 2 ignitors firing each coil off it[s own channel? If not you'll only loose spark energy and miss more up top. I run NGK BR7ES plugs (dropthe "P" in the BPR7es plug as it's a "protruded electrode, which can be a hotspot inducing knock as well) I gap mine at .020 and run an MSD DIS-2 controlled by a haltech EMS and only run 3.0ms from the ecu to a stock igniter that fires off the MSD which in the final equation is controlling dwell on it's own, but by running less from my ECU i get more accurate signals to J&S safeguard
I've been on ethanol for a couple years now and many many different tunes and unless I'm at a displayed AFR of 12.5 - 12.8:1 at anywhere from 25 - 30psi i get massive rich knock and i run a J&S safeguard knock sensor (adjustable stand alone knock system that interrupts the signal to the igniter to delay timing and does so only on the cylinders that are knocking while trying to feed timing back as fast as it can... BEST thing since sliced bread IMO, i ran without any knock sensor for near 10 years of just tuning by experience of what engines do to display things like knock and what not and using a wide band and EGT's to tune , only time i ever popped an engine was with a faulty wide band that told me I was at like 11.5:1 when i was actually running 14.7 and leaner under 20+psi
Even then on pump i ran a timing curve of 14-16* at peak torque to 19 - 21* at peak RPM and just adjusted boost to compensate and remove det. This new tool has taught me so much more since i know it's not picking up a ton of false knock and i can filter what is real and what's not since i can see what every cylinder is doing and aside from internal engine noises like some slap when free revving and the AC compressor setting off the KS (but you can tell when it's real det) but i have found that when reading gas AFR's anywhere 12.0 and richer will cause rich knock/misfires out the ass
So let me ask this.. at the "1.2* timing"... where do you drop into that (RPM and MAP reading) and how...are you dropping straight from say 30* at 3k RPM and say 4in/hg vacuum to 1.2, then at a a certain boost just throw timing back in? If so you you should post a screen shot of that timing map as I'd love to see it and don't have the AEM software on my desktop.
And what has this done or your spool up? I would think it would be close to anti lag but wondering how much RPM earlier you hit full boost
Also, you have to watch for something called "timing attack rate" which is how fast and how far up you bring the timing under any given condition as this can cause rapid peaks in cylinder pressures making you get an erratic knock from pressures rising so fast.. you are better to not let them drop too low to where you have to bring it back up fast anywhere and up should
also watch how much you advance the timing with RPM (say like adding 1* per 500 RPM which is safe versus 5* per 500 RPM which would be a very fast and probably way too excessive attack rate too fast of an attack can produce more pre-det on very little timing than more timing that starts being high and rises slower since cylinder pressures are more constant... and remember having timing too low can put the peak cylinder pressure timing so far behind that it's actually happening while the piston is already past it's point of transferring usable energy from the rod to the crank because of crank position being too late (crank already past 90* on it's way down)
damn, my posts are always pages long, but i wanna add, notice how knock rises with RPM steadily.. I think you are just seeing engine noise for the most part, but you know your system better than me, i've tuned a lot of AEMs but there's adifference in DD"ing a car with that system and tuning them here and there
To the OP, do you have enough left over outputs to fire the COP sequentially so you can run 2 ignitors firing each coil off it[s own channel? If not you'll only loose spark energy and miss more up top. I run NGK BR7ES plugs (dropthe "P" in the BPR7es plug as it's a "protruded electrode, which can be a hotspot inducing knock as well) I gap mine at .020 and run an MSD DIS-2 controlled by a haltech EMS and only run 3.0ms from the ecu to a stock igniter that fires off the MSD which in the final equation is controlling dwell on it's own, but by running less from my ECU i get more accurate signals to J&S safeguard
I've been on ethanol for a couple years now and many many different tunes and unless I'm at a displayed AFR of 12.5 - 12.8:1 at anywhere from 25 - 30psi i get massive rich knock and i run a J&S safeguard knock sensor (adjustable stand alone knock system that interrupts the signal to the igniter to delay timing and does so only on the cylinders that are knocking while trying to feed timing back as fast as it can... BEST thing since sliced bread IMO, i ran without any knock sensor for near 10 years of just tuning by experience of what engines do to display things like knock and what not and using a wide band and EGT's to tune , only time i ever popped an engine was with a faulty wide band that told me I was at like 11.5:1 when i was actually running 14.7 and leaner under 20+psi
Even then on pump i ran a timing curve of 14-16* at peak torque to 19 - 21* at peak RPM and just adjusted boost to compensate and remove det. This new tool has taught me so much more since i know it's not picking up a ton of false knock and i can filter what is real and what's not since i can see what every cylinder is doing and aside from internal engine noises like some slap when free revving and the AC compressor setting off the KS (but you can tell when it's real det) but i have found that when reading gas AFR's anywhere 12.0 and richer will cause rich knock/misfires out the ass
So let me ask this.. at the "1.2* timing"... where do you drop into that (RPM and MAP reading) and how...are you dropping straight from say 30* at 3k RPM and say 4in/hg vacuum to 1.2, then at a a certain boost just throw timing back in? If so you you should post a screen shot of that timing map as I'd love to see it and don't have the AEM software on my desktop.
And what has this done or your spool up? I would think it would be close to anti lag but wondering how much RPM earlier you hit full boost
Also, you have to watch for something called "timing attack rate" which is how fast and how far up you bring the timing under any given condition as this can cause rapid peaks in cylinder pressures making you get an erratic knock from pressures rising so fast.. you are better to not let them drop too low to where you have to bring it back up fast anywhere and up should
also watch how much you advance the timing with RPM (say like adding 1* per 500 RPM which is safe versus 5* per 500 RPM which would be a very fast and probably way too excessive attack rate too fast of an attack can produce more pre-det on very little timing than more timing that starts being high and rises slower since cylinder pressures are more constant... and remember having timing too low can put the peak cylinder pressure timing so far behind that it's actually happening while the piston is already past it's point of transferring usable energy from the rod to the crank because of crank position being too late (crank already past 90* on it's way down)
damn, my posts are always pages long, but i wanna add, notice how knock rises with RPM steadily.. I think you are just seeing engine noise for the most part, but you know your system better than me, i've tuned a lot of AEMs but there's adifference in DD"ing a car with that system and tuning them here and there
dont hate on the ear muffs man! sure you look like a ####in retard driving around with them on, but this is actually FAR superior to electronic knock detection.
