And the 20 reasons that outweigh it arent considered i guess.. LOL

Mike

 

why are experienced ppl's advice been ignored
why not just show the timing map?

 

I switch back and forth during an oil change interval as well....according to the oil analysis I had done after a 5k mile period it didn't make a difference, all was well.

 

Oil change... According to the several analysis's that i have done, this does not have any affect. If you follow the regular schedule you should be fine. Its not a bad idea to change it when you switch the first time (heck.. your getting service done to it, might as well do the oil), but definately not required every few hundred miles. Save your money and go buy some more chrome for the car.

I have been running E85 for 2 years now. No issues at all. Depending on how far i am from E85 i switch back and forth from E85 to pump 91.

 

i would never give up e85.... i tune for 11.8-12 a/f at night and then during the day it becomes about 11.5-11.6 or so. here is my timing map. i am just going by what VDR shows me, so im not going anymore then this until i see a real life dyno. 3* peak tq and 17* uptop

 

Very good to know!

 

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.

 

for 3* @ peak tq your turbo would have to hit full boost by 2000 rpms unless you are getting knock..

 

im not using that map anymore. my car only wants 1* at peak, anything more and it loses torque. It may have been knocking with that map downlow, because i had the knock sensor disabled down there. now i know for a fact its not knocking anywhere tho. timing starts high and goes low, then from peak load area it slowly climbs up, so its doing what its supposed to.

This maps unfinished, i can get more timing uptop. I am doing another project on car atm tho, suspension work.

 

well motors dont just blow up for no reason - with that said i know you went over mbt. ive went over mbt more then once now on my own vehicle with e85.

 

I would say 8* at peak torque on a 10.5:1 motor at your power levels on E85 was definitely past MBT and most likely was the root cause of your problem. E85 just doesn't take as much timing at peak torque as you would think.

On my stock turbo, I'm making about 400wtq at 30ish psi at only 0* peak timing. I stopped there just because I didn't have access to a real dyno and knew MBT at peak torque wasn't too far away. I could do logs and virtual dyno runs, which I did up to that point, but I just didn't want to push it further, due to this being my daily driver and stock bottom end.

There are plenty of tuners that have tuned numerous E85 cars though, and have published their timing maps and findings as well. Bryan at GST is one of them that comes to mind. From what I remember from his comments, he has found MBT on a ton of E85 cars and his timing at peak torque is very conservative as well...maybe 3* if I am remembering right. Keep in mind this is on standard compression motors as well.

Timing can be ramped up pretty agressively after peak torque area, and I doubt your peak numbers at redline were an issue. But, peak torque seems to be a different story with E85...and of course AFRs, where E85 seems to like it rather lean.

 

yeah, I have seen plenty of posted numbers. if you go to dsm tuners or ecm tuning sites and see their e85 posted numbers you will see what appears to be more aggressive numbers posted. I do have early evo and burn rate of the earlier engines may be a tad slower than evo 8 engines. plus i did road tune the base timing and it was pulling hardest were it was. From what you are suggesting if you go past MBT by 3-5 degrees that is enough to bend a rod? I just seriously doubt that. it would develop more MBT at TDC yes. but rod is straight up in engine and wont bend in that position. Remember MBT for all engines occurs at 15 after TDC for all engines. Going past MBT say by 5 degrees means the new MBT is at 10 degrees ATDC. that will just loose power. its not gonna hurt the engine.

There are plenty of meth users who have lost engines from hitting rev limiters . I believe it is widely accepted they are finding preignition from wasted spark as well. preignition is FAR FAR harder on rods than detonation or going past MBT by a few degrees. Just because people are reporting misfires with e85 and no bent rods doesnt mean it didnt happen with my setup or others who experienced same problem. I have hit rev limiters on meth injection plenty of times and was lucky enough to not bend rods. Does that mean it will never happen because it didnt happen for me?

In the end I wlil stick with the preignition theory as being correct one.

 

you make me scared to go e85 now:/

 

I don't disagree that preignition is far worse....what I am disagreeing with is your theory about misfire and ignition of the wasted spark. Ignition on the wasted spark would occur with valves open and virtually no pressure in the cylinder.

Preignition on the event spark...that is a totally diffferent story and most definitely can and most likely will blow your motor. Preignition on your event spark is just like running way past MBT. All of that pressure has to go somewhere and something has to give....headgasket, pistion, rod, etc.

But preignition on your event spark isn't occuring due to misfire. If you are experiencing that, it's coming from something else...wrong heat range plugs, hot spots in the combustion chamber, etc.

As far as just generally being past MBT and whether or not that was your contributing factor....like you mentioned, we don't know your burn rate or your particular motor and other variables that are involved. But being past MBT by any amount is stressing the rod. Again, that pressure has to go somewhere. The least of which may be beat up bearings. The worst of which, over prolonged use would be damage to the rod. Enough to bend your rod, I don't know....we would just be guessing at that point. You said that it was 'pulling hardest' at that point, but I don't think butt dynos are that accurate. Without seeing logs or true dyno sheets at various timing levels at peak torque, we are just guesssing again.

In any event, I hope you don't have any future issues with your new setup. I think tuning for MBT this time would be wise, even if you don't think that's the culprit. Obviously looking into the ignition system and correct heat range plugs as well would be good.

 

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?