missfires and E85 = bad news
May 8, 2010, 01:07 PM
#62
A stock evo engine can rotate 1 degree as quickly as 22 us (redline). So even if it only takes 1 millisecond to reach peak pressure, that's ~45 degrees of crank rotation.
d
May 8, 2010, 01:11 PM
#63
Sort of related...sort of a thread jack...
If we can all agree that misfire at or near peak torque has got to be a bad idea, is there any strategy for tuning with E85 that can minimize the usual torque spike and yet maximize HP?
I suppose an RPM based EBC might work? I can't really think of anything the stock ECU could be set up to do differently? Any ideas?
If we can all agree that misfire at or near peak torque has got to be a bad idea, is there any strategy for tuning with E85 that can minimize the usual torque spike and yet maximize HP?
I suppose an RPM based EBC might work? I can't really think of anything the stock ECU could be set up to do differently? Any ideas?
example. with my current ecu controlled boost i can reach 30psi around 3.5k on 3rd. you can set it up to control the load(if load based) or psi(if psi based) and just delay the ramp up a bit like maybe 500rpm later. that should decrease the torque spike
May 10, 2010, 02:56 PM
#64
my engines a good example. at 0* it makes slightly less power then it does at 1* and anything over 1* loses power. that tells me 1* is where it wants to be. going from 3-4* at peak to 1* yielded over 70wtq on vdr. thats from just 2degrees in change. - I then went from 12* at 6500+ to 14* and gained another 37whp on vdr. Im 99% sure i can get out 18-19* uptop (another 100whp), but im going to let another tuner extract the power for me on a dyno because i have nothing to prove by tuning my own vehicle at this point. If i were seeking it as a career i would proceed on the dyno myself, but im not. It is very fun tuning your own vehicle tho and watching the car wake up and come alive.
May 10, 2010, 03:15 PM
#65
Sort of related...sort of a thread jack...
If we can all agree that misfire at or near peak torque has got to be a bad idea, is there any strategy for tuning with E85 that can minimize the usual torque spike and yet maximize HP?
I suppose an RPM based EBC might work? I can't really think of anything the stock ECU could be set up to do differently? Any ideas?
If we can all agree that misfire at or near peak torque has got to be a bad idea, is there any strategy for tuning with E85 that can minimize the usual torque spike and yet maximize HP?
I suppose an RPM based EBC might work? I can't really think of anything the stock ECU could be set up to do differently? Any ideas?
ebc's are nice tho. grimspeed ebc is one of the nicer ones for the stock ecu.
May 21, 2010, 04:40 AM
#66
Got car back together. Still had some e85 left to burn through so I took a look at the timing numbers. The head and block are same and cams/ timing was untouched. The differences would be the new engine is 2.3 with 9/1. the old was 2.0 with 10.5/1. the boost was also turned down. just running waste gate on the 2.3 was getting about 23psi settling to 20psi. the timing on the logs showed 2.9 at 3500rpm climbing to 14 at 7000rpm . But then you have to add the base timing which was another ~5. so 8 climbing to 19 at 21ish psi doesnt sound like rod bending numbers to me. Sounds more like spot on for making nice power, which it was. On the 2.0 i was running more like 32psi falling to 26. The weather is also much hotter now. 50-60degrees on the 2.0 and 90s with the new 2.3 setup. How much timing there would be with higher loads and cooler temps is not known.
2degrees at 3500rpm and 13degrees at 7000rpm. those timing numbers are good for 30psi no problem.
May 21, 2010, 04:54 AM
#67
Each individual coil fires two spark plugs at one time, one spark plug on a compression stroke (which is where the power comes from) and one spark plug in another cylinder on an exhaust stroke, simultaneously. This method of "double firing" also reduces exhaust gas emissions because the spark plug that is fired during the exhaust stroke burns (or cleans up) remaining fuel left over from the previous combustion stroke before it has a chance to exit the engine through the tail pipe
May 21, 2010, 05:10 AM
#68
I also found my boost curves were not what I thought. I was quoting boost numbers from my peak hold greddy gauge. I thought I was getting boost spikes by looking at my gauge. After watching sensor load in logs I found very flat boost curves. the boost rises so fast the mass of needle cant stop fast enough and gives a false overshoot of boost at gauge.. was making it look like I had more boost at peak torque than I actually have.
May 21, 2010, 05:44 AM
#69
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I guess I am the only one having major issues with E85. I have toasted two engines now from having missfires on E85. I first bent a stock evo 8 rod. I then built a eagle rod engine for car that suffered the same fate. Neither engine has any sign of detonation. very conservative tunes with EGT not exceeding 750. A/F in the low to mid 11s.
My take on what is happening. If you have a misfire with e85 the exhaust stroke will be pushing an ignitable mixture. at TDC on exhaust stroke there is that darn wasted spark. This ignites the mixture. Since ethanol burns slow and long the burning mixture continues till the new A/F charge enters. The piston traveling up the bore toward firing stroke is met with already expanding fire. With the crank pushing rod up and fire pushing piston down and the rod being at an unfavorable position you have the perfect senario to bend a rod.
I have very quiet exhaust on car and very perceptive tuning ears. So I caught both engines before a rod was thrown out side of block. I believe others who have blown motors on E85 may be having misfires as well. But just arent aware of this prignition condition that results. No rod is sacred. Rods arent designed to be strong in the position that causes this bending force.
I am bailing on the E85 dream for now. I am building a new block for car and I am going to return to 93/alky injection. I found an unbelievable alky injection pump. Will make a new thread on that.
My take on what is happening. If you have a misfire with e85 the exhaust stroke will be pushing an ignitable mixture. at TDC on exhaust stroke there is that darn wasted spark. This ignites the mixture. Since ethanol burns slow and long the burning mixture continues till the new A/F charge enters. The piston traveling up the bore toward firing stroke is met with already expanding fire. With the crank pushing rod up and fire pushing piston down and the rod being at an unfavorable position you have the perfect senario to bend a rod.
I have very quiet exhaust on car and very perceptive tuning ears. So I caught both engines before a rod was thrown out side of block. I believe others who have blown motors on E85 may be having misfires as well. But just arent aware of this prignition condition that results. No rod is sacred. Rods arent designed to be strong in the position that causes this bending force.
I am bailing on the E85 dream for now. I am building a new block for car and I am going to return to 93/alky injection. I found an unbelievable alky injection pump. Will make a new thread on that.
and eagle rods chineese made rods = parts just as strong as stock. So fail
u need some Buschur in your life
Jun 7, 2010, 10:14 AM
#71
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Im not sure how intellegent of a question this is but does most engine failure occur at wide open throtte, because id be hella suprised if the car blew up on like 5-15 psi. also, how do you know if your misfiring, because i think i could be the misfire king on 93oct. the way my car sounds.
Jun 13, 2010, 12:16 PM
#72
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I recently threw a rod on my stock motor/turbo VIII on e85 running 29-30lbs. I have been running e85 on and off for over a year, and have had 2 different professional tuners tune my car as well, including on a dyno where we were able to see results of adding/subtracting timing. Even though I was tuned professionally, I always ventured off making changes on my own, and my tune that I have been running for months was created by me from scratch on Tephra V7. Usually I run 6-7deg at peak TQ, and up top somewhere around 20deg. Attached is my self-tuned timing map, which I have been running for about 5 months with e85 only.
Interestingly, I was having misfire issues at peak torque for a couple weeks, and when my motor went it seemed like it misfired like it had several other times before. My rod went when I was at ~3200rpm at almost full boost. I was running bpr8es's gapped at ~.019.
There was a thread on my car here: https://www.evolutionm.net/forums/ev...own-motor.html, but I thought I would share this information in this misfire thread, since there is a possible connection. It could also be that I just ran too aggressive timing for too long...
Interestingly, I was having misfire issues at peak torque for a couple weeks, and when my motor went it seemed like it misfired like it had several other times before. My rod went when I was at ~3200rpm at almost full boost. I was running bpr8es's gapped at ~.019.
There was a thread on my car here: https://www.evolutionm.net/forums/ev...own-motor.html, but I thought I would share this information in this misfire thread, since there is a possible connection. It could also be that I just ran too aggressive timing for too long...
Jun 13, 2010, 12:23 PM
#73
That seems like a bit too much for peak torque to be on the conservative side of things. You said that you were dyno tuned before...where was MBT found for peak torque on your setup before you retuned yourself?
I keep mine pretty conservative just because this is my daily driver. I also run 30+ psi on E85/stock turbo and have been for probably over a year now. But, I run around 1* peak torque. I never had the chance to get to a dyno to find MBT, so I simply did a few pulls with VDR to create a very nice, conservative tune. No need to push thing to get every drop of power on the stock bottom end.
Looking at you map, you probably won't ever hit those cells, but why are you increasing timing in the areas of high load, low RPM. Like look at 300/2500 area....9*? Also, just picking a random RPM like 3500...you have 7* of timing from 250 load all the way to 310 load? What is your thinking there? Perhaps 7* at 250 is too little or 7* at 310 is too much, but there should be some sort of taper going on there. You will need less ignition advance at 310 load than you will at 250 load. But, again, it all matters what your method to find these numbers were. That's why I asked where MBT was found for your timing curve when you were dyno tuned.
I hope you weren't going by knock to tune your E85.
I keep mine pretty conservative just because this is my daily driver. I also run 30+ psi on E85/stock turbo and have been for probably over a year now. But, I run around 1* peak torque. I never had the chance to get to a dyno to find MBT, so I simply did a few pulls with VDR to create a very nice, conservative tune. No need to push thing to get every drop of power on the stock bottom end.
Looking at you map, you probably won't ever hit those cells, but why are you increasing timing in the areas of high load, low RPM. Like look at 300/2500 area....9*? Also, just picking a random RPM like 3500...you have 7* of timing from 250 load all the way to 310 load? What is your thinking there? Perhaps 7* at 250 is too little or 7* at 310 is too much, but there should be some sort of taper going on there. You will need less ignition advance at 310 load than you will at 250 load. But, again, it all matters what your method to find these numbers were. That's why I asked where MBT was found for your timing curve when you were dyno tuned.
I hope you weren't going by knock to tune your E85.
Last edited by l2r99gst; Jun 13, 2010 at 12:31 PM.
Jun 13, 2010, 12:26 PM
#74
Thats what I was thinking l2r99gst. That seems a bit high depending on the motor he has. I never dyno'ed my new setup either, but just from playing around you can tell what is good and whats not. i lose gobs of torque when i give it to much at peak tq.
some tuners think its ok to tune e85 until it knocks, so possibly his tuner didnt understand how to tune e85 100%.
some tuners think its ok to tune e85 until it knocks, so possibly his tuner didnt understand how to tune e85 100%.
Jun 13, 2010, 01:00 PM
#75
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I take responsibility for my current tune. One of my tuners had tuned numerous high hp cars on e85 and had it slightly more conservative than I did. My other tuner had it more aggressive than I did, running 8deg at peak TQ and 22deg up top which I thought was too much based on what I saw with VDR. l2r99gst, I seemed to stop making additional power after ~6deg at peak TQ for me. There were areas of that map I needed to fix, but I generally had flat'ish' timing from 250-300 load since that is what my car liked. I would knock down low if I spooled on much more timing which would pull my timing everywhere. I was not careful to correct areas of the map I would not really hit, but I was meaning to smooth everything out.