648whp on Pumpgas
Dec 22, 2010, 11:04 AM
#19
Eric, I didnt post the MIVEC on this log but that and the cam gear seem to be the key much as you had told me. 94 Cenex is E20 it seems. I have fuel for it but I am curious if straight 93 is any different or octane is octane and its all about the same deal? Call if you get a chance.
aaron
aaron
Dec 22, 2010, 08:56 PM
#24
It's been a while since I read JCSBanks thread, so the details could be missing. Knock sum is based on the knock voltage peaks going above a moving average of the knock voltage. You get knock counts when the peak goes above a certain threshold above the average knock sensor level.
If the moving average gets high, because of either a noisy motor, sustained detonation, or just loud combustion, you can easily max out the moving average value to the point where the knock sensor cannot put out a signal high enough to trigger the knock sum counter.
This can happen on pumpgas pretty easily, as from what I have noticed, as you drop the ignition advance it makes the combustion event more noisy and the average knock sensor voltage will climb. The same thing happens with RPM, the higher the revs, the higher the average knock voltage level.
Knock sensors work for the typical 400HP build. They are pretty reliable down at the lower RPM ranges too (below 6000 RPM, IMO). But once you start pushing a setup hard on boost or RPM, I would never rely on the knock sensor. Also, built motors can negate all this, as I've seen numerous that manage to max out the average knock voltage pretty early on. Some items are particularly noisy too. On a friends car with a Peterson external oil pump, it would max out the knock sensor by like 2000 RPM.
Aaron, can you post up that same pull but with smoothing set to 0?
If the moving average gets high, because of either a noisy motor, sustained detonation, or just loud combustion, you can easily max out the moving average value to the point where the knock sensor cannot put out a signal high enough to trigger the knock sum counter.
This can happen on pumpgas pretty easily, as from what I have noticed, as you drop the ignition advance it makes the combustion event more noisy and the average knock sensor voltage will climb. The same thing happens with RPM, the higher the revs, the higher the average knock voltage level.
Knock sensors work for the typical 400HP build. They are pretty reliable down at the lower RPM ranges too (below 6000 RPM, IMO). But once you start pushing a setup hard on boost or RPM, I would never rely on the knock sensor. Also, built motors can negate all this, as I've seen numerous that manage to max out the average knock voltage pretty early on. Some items are particularly noisy too. On a friends car with a Peterson external oil pump, it would max out the knock sensor by like 2000 RPM.
Aaron, can you post up that same pull but with smoothing set to 0?
I pretty much just reved my car in neutral and it knocked when i knew it wasnt possible due to my maps and adjusted the multipliers slowly until it read zero.
back it off one point and show knock again, then set it back again and you know its set safely. some people also adjust the multiplier until it barely shows knock then adjust sensivity until its gone.
Lot of phantom knock comes from the head usually. I had tons of it due to my kelford cams. Also lots come from clutches also. but for the most part can appear from anything. I always shake stuff in my engine bay to confirm nothing hits nothing.. Ic piping, shake it up and down left and right etc, you may be very surprised what you find that makes noise in your engine bay.
Everyone has their own way of adjusting the sensor, if it works it works.. i choose my own way.
Just dont say the sensor is not useful after 400whp, because that is not true. the sensor can be setup to withstand any engine noise, the hard part is getting it adjusted for the noise environment without disabling it at the same time.
If that pump was louder then the entire engine itself and you had to drownd out that pump noise then that is a example of how the knock sensors no longer functional.. cause if you have to drownd out a noise thats louder then the actual engine then the knock sensors never gonna pick up knock for the most part, then id get electronic knock headphones etc.
typical evo even 600whp builds can use stock knock sensor just fine though granted nothing crazy is going on like example above.
Dec 22, 2010, 09:12 PM
#26
aaron are you still running the 92 in your evo now? im curious as to how many MPG you can actually get from the 92oct WOT or just beating the crap out of the car constantly as opposed to it on e85 at the same boost with more timing.
92octane last noticeably longer right? do you notice any differences in cruise with 92-93 vs e85? like peppiness in the car etc? im going to put 92 in mine here soon cause 92 is whats standard here and then the other map for e85 of course.. 92 just for a fail safe map tho or road trip.
92octane last noticeably longer right? do you notice any differences in cruise with 92-93 vs e85? like peppiness in the car etc? im going to put 92 in mine here soon cause 92 is whats standard here and then the other map for e85 of course.. 92 just for a fail safe map tho or road trip.
Dec 22, 2010, 09:17 PM
#27
gasoline I average 24.1mpg, E85 I average 17.5. This is all if I am nice to it. The tank that I am on now is about gone and I have gone 240 miles already and that includes the dyno session where I swear the needle moved an eighth of a tank. Light comes on right before 12 gallons is used up so I am still on the upside of 20mpg.
I work alot on cruise and mileage, the feel of the car is the same between the two just worse mileage on Ethanol.
I work alot on cruise and mileage, the feel of the car is the same between the two just worse mileage on Ethanol.
Dec 22, 2010, 09:24 PM
#28
very nice.. well you definitely have the best of both worlds with your car. i take it you did your homework when choosing your setup and knew it was gonna perform like this on pump and e85. the powerbands great, not overly laggy, not overly to quick of spool.. seems just right.