depending on the E concentration you will not get any knock. E can remove the knock limitation and allow you to reach MBT. So no blown motors due to knock itself.

Trouble is you will not really know where MBT is without a dyno So once you go past MBT you over stress the rods which can lead to failure but you still don't get any knock.

you can however make much more power very safely by running a mix and say add a degree or so more than you were on 91/93 and knock limited. This is why Phate put together the database so you can see what others are making on dynos with varying E mixes and hardware.

for the love of god......all i can tell you guys.....tune your knock sensor on 93/91 and then copy it over to your e85 map...DO NOT tune out "ENGINE NOISE" when on your e85 map...

Knock you get while on e85 should raise some alarm to you if you do this all right....My be a good time to back timing down and or get on a dyno and actually tune your shit.

Dunno, I am still knock limited on a 3/9 mix, and there is no way I am running my 93oct timing +1/2deg. I was knock limited at 9* peak on pump @ 11.2AFR, and the mix allowed me to gain over 80whp through 8* more timing and 12AFR.

Note though, I am using a load tune with the express purpose of keeping cylinder pressures manageable over varying temps. It's only hitting ~16-17psi in the 3-4k range now to maintain ~400wtq with the extra timing and 50deg ambients. Past MBT or not, the extra timing plus a boost tune thats just going for 22psi would be headed towards 500wtq quickly. Even running at MBT significantly increases cylinder pressures while having a small effect on power.

Just some sketches done from memory to illustrate my point. Even reaching MBT significantly increases cylinder pressure. First up your basic cycle using instantaneous combustion.
Attachment 48148

Now a couple figures for non-instant combustion

Attachment 48149

The key is you never achieve peak pressure directly at TDC when at MBT; you lose more power by having combustion going on while compressing (hogher pressure at point 2) than gained so you stop adding timing. However going past MBT moves point 3 closer to TDC and up that exponential cylinder pressure curve.

hahah at pulling out engine cycle diagrams. A little too much thermodynamics for me.

^Agreed. @Ziggo, just because I thank you doesn't mean that I have the slightest clue what you're sketching, but I appreciate your effort to explain things to the simple folk here (me). :thinking:

It all always comes back to thermodynamics!

Oh YEAH. Thermo FTMFW!

speaking of thermodynamics...

as a chem-e thermo was probably my least favorite....along with process control. I was all about transer, whether it was fluid, mass, or momentum.

P-V diagrams and Otto cycles make me wet.


Tapadatass

My "common sense" way of thinking/explaining is to imagine pedaling a bicycle, but you weigh 2000 lbs or something and can only pedal standing up/full force on the cranks one foot at a time.

You can push down on the pedal when it's parallel with the ground, and get good power, but if you push down earlier you can get more work out of your weight up to a point. At some point the force you're exerting is putting much more stress on the pedals/cranks than is being transferred into the chain to propel you forward. Ever earlier in the cycle almost all your weight is going directly into the crank arm for awhile before it gets around, and it bends/snaps.

As I mentioned in the other thread, but this seems an appropriate place to repost:

WTF are you engineers talking about??? i put corn into my car and I go faster...nuf said??

I could throw up a DJ MS paint drawing to illustrate what I mean but I think its clear and besides....I've had too much to drink...

Switched to E25, first scrapper logs
 

I went with 4 gallons of E85 today, and topped it off with premium (~E25). I added about 13% fuel up top on my maf curve, and staggered it down to 5% around 125 g/s or so. I've only driven about 12 miles on the new map, and went wot from 2nd-3rd near my house. My wot afrs weren't that bad... a little rich, but not that far off.

Once the map settles, I'll do a maf g/s and cal the lower part of the maf, flash that map, then do some 4th pulls. I could only run 11* timing up top before with 0 kr, but I bumped it to 14* timing for my base map. It hit 14 NP, and no kr, so that's a good place to start. I'll have her leaned back out to 12.0 afrs, and I'm hoping I can run 16-18* timing up top. I'm pushing about 25psi, and I may squeak it up to 26psi.

Too rich/soon to feel any big sotp gains, but I'm hoping once she's dialed that she can break 400whp SAE. We'll see... dyno is less than 3 weeks away, and I need to get tweaking! Also, my IDC% is right around 100% now, and the E85 skewed my maf about up by 30g/s up top.

EDIT: Added a 3rd gear pull from 2,800 rpms to redline. Looks solid, just rich and needs more timing.

looks like some good air ingestion goin on there.

At your airflow levels... i'd run as little e85 as possible to keep kr away. You need the fuel.

Yes I agree with DJ to an extent. I think you can make more power with the e85/timing combo vs the added 1-2psi and less e85 like he is suggesting. If you can keep your 4g to 8g mixture I think you can make 400whp NO problem. I dont suggest running 4g to a top off. eventually your mixture will be off. When filling next time do 4g to 8g. Make sense? You should be able to go all the way to 19-20 degrees timing without any knock and from the 11 degrees you were at before you will make about 40-50whp more. Id try keeping boost around 24psi and start timing around 16-17 degrees on the dyno and add 1 degree at a time until you stop making power. If you are still around 100% idc I would suggest leaning out some more to around 12.4-12.5 afr to give yourself a lil room on idc. This is still a very safe afr on your setup and will give you that lil bit of breathing room. Good luck and keep us posted. Im excited for your results.

I concur with pulling boost to 24psi and then push timing.

Here are your tradeoffs:

The more boost, the more power.
The more boost, the more fuel needed.
The more boost the more heat, the more knock.
The more heat, the less timing.
The more timing, the more power.
The more fuel (richer) the more cooling.
The more E85, the higher the octane, the less knock.
The more E85, the more fuel needed.

just think of the things some you could accomplish if we all werent fuel limited.

So has anyone figured out the size of the o-ring that seals around the pump piston? Mine is wearing and I need a new one.

I bought a full Buna-N quad O-ring kit from McMaster-Carr and it's sitting in my garage waiting for me to find the time to test some O-rings out.

I'll try to get an answer on the size this weekend.


Tapadatass

Thank you, it is GREATLY appreciated. You da man :439:

I'm reading more and more evidence that it may be best to go to a 2 step colder plug rather than back to the stock heat range if running high eth mixtures.

I know many of you guys read as much as I do, but it seems that ethanol is particularly sensitive to preignition.

I think cld12pk2go ran itv24's for a long time on his eth mixes with good luck.

My car ran much better after taking out my 1-step-colder Denso's and putting in stock heat range plugs.


Tapadatass

My car has run better on stock heat range plugs compared to ITV22's. When I was running 22's, the car ran shitty at idle and WOT, with some hesitations here and there. The 20's work great until around 35° ambient temp. I would actually like to try ITV16's (1 step hotter than stock) to see how they work in winter.

Quick google search for auto ignition temps of various hydrocarbons, including ethanol and gasoline: http://www.engineeringtoolbox.com/fu...res-d_171.html

And here's an SAE paper if anyone wants to pay for it: http://papers.sae.org/2008-01-0321/


Edit: I think my intercooler delete testing shows just how damn awesome E85 is. back to back to back runs with 230°+ BAT's with full boost and full timing and my shit didn't go nuclear. I really don't think it's a concern, lol.

Alrighty guys, just saying I'm reading over and over again some of the more experienced tuners for many of the platforms quoting various sources, that preignition is an issue with ethanol.

I understand on paper, things can be debunked, but we all know that things don't always behave in nature as they do on paper.

Here we go:

Phate, you posted that to show bat's< temperatures listed for auotignition in the link you provided?

FYI, i have had zero issues with the ITV24's with up to E50.

I am currently in the E35 range without any issues down to 18°F ambient temp so far.

Of course I am now pushing close to 350 g/s actual, which might require something quite different from a K04 at similar ethanol concentration.

Consider post-compression temps of the same mass of air between a 100° pre-compression charge and a 250° pre-compression charge. Someone want to run some numbers for us???

I'm not disputing your scientific approach, although I do think that the amount of shit that is stuck to our plugs could tend to cause an issue.

I didn't intend to debunk your science, I'm simply stating what I am reading from some pretty experienced ethanol tuners, as well as some of what I've read from various sources.

IDK man. Like I said about 50 pages back (lol), I'll let you smart folk discuss why or why not we can or cannot do things, and I'll just keep testing and reporting my findings.

Ha! I said the same thing about nutrition 5 years ago... It worked out well to say the least.

Firsthand/Frontline empirical data is ALWAYS the best data!

Keep doin your thing playa! :bigok:

IDK either Phate, just brought up something I read on numerous sites, numerous times.

I didn't mean to challenge your intelligence, nor your findings, just participating with some of what I read.

It is a commonly excepted issue that ethanol's only weakness is its predisposition to preignition.

Just to show you that I read something I thought was of interest from a credible source concerning plug heat range, the following is from ngk's website:



Fuel Type / Quality


When using an ethanol blend fuel with high ethanol content in high performance applications, a colder heat range may be necessary. The spark timing can be advanced further because ethanol blend fuel has a higher resistance to knock (higher octane). Due to the decreased knock, there will be less audible “warning” from knock before the spark plug overheats and pre-ignites.
Some types of fuel additives in lower quality fuels can cause spark plug deposits that can lead to misfires, pre-ignition, etc.

I just downloaded the SAE paper. Gonna take a few minutes to read, lol.

How much was it? I'll split it with you.

You read it.LOL

Have you guys been checking your plugs much? I'd be real curious to see how yours looked after that IC delete test Clint.

Pre-ignition would result in some pretty hefty holes in pistons pretty fast. Anyone had this show up?

http://www.aa1car.com/library/piston...ion_damage.jpg

Is this the paper. I think I will buy this since I'm a member of SAE.

Pre-Ignition Characteristics of Ethanol and E85 in a Spark Ignition Engine

That is another issue that is totally different with e85, plug reading.

From what I can tell, you can throw traditional plug reading out the window.

That is the paper^