c6 batmobile

Thats what I gather. If you dont adjust the value the car doesnt benefit from the richer higher octane fuel.

SpinMonster

Lighten up.

It wasnt intended to disrespect you but you came in here saying I have bad info acting like your the authority. "No Spin, not trying to start a fire but it doesnt add up, I need proof". You need proof that 16% of a tank filled with E85 raises octane and gives a power benefit?

Yes last year you and about 100 other people answered beginner questions for me on the topic. Its not last year anymore. I credit Tyler (outlaw on youtube) as the main source of this info and he and his shop do this mod to countless cars. The idea being that you need not use a full tank of E85 because with any build, the limit of the power doesnt always require 105 octane. This opens the door to varying amounts of E85 in the mix with E10, hence using varying amounts of E85 as octane boost so you dont eat up precious injector and fuel pump capacity. For anyone that built a car over 700rwhp, they know how important it is. I posted a chart on stoic, PE and approximate octane. If you see anything wrong, correct it. Dont just imply fault on my part. If youre all hung up on it being 94.6 octane instead of 95....

Actually it does in this case. If you based you're whole debate on that, you should take the time to verify that statement. I did. Different fuel compositions such as Avgas doesn't use the same calculation and mixing a fuel that uses one calculation with another fuel with a different calculation would make your statement true. In the case of E10 and E85 it is equal to the A+B/2 result and is linear for most hydrocarbon and oxygenated fuels.

I think what happened here is you quickly skimmed through and judging by your posts, you thought I said E20 is the same power gain as E85 or something like that. I clarified but you didnt want to comment. You can use varying amounts of E85 to perform the function of octane boost...the title of the thread. You have to tune for it thus the table with values that work on real cars north of 700rwhp with awesome results.

I dont know how else to package this a nicer way but to welcome your discussion. If you dont want to discuss and just want to call BS, dont think it makes you look like the genius just to say someone is wrong and try to make yourself look good that you answered a few basic questions in the beginning of a guy's search for info. That search went on long after our last PM with many credible sources who build very high HP cars. Your first post claimed you didnt agree with this mod. Your second post was designed to make it look like you taught me everything I now know about ethanol tuning. Dont kid yourself.

RLSebring

Spin, Just a quick question kinda on topic about timing. I have tried to get my head around this ...

I am running 19 degrees in my idle base spark table and the car seems to like it. As I understand it the tables switch to my high octane table as soon as it starts rolling. I am at 35/36 degress in the same idle range on the high octane table. Should there be a smoother transition between these two table or is that just the way it is.

I am constantly looking for that particular area in any table to smooth out to get my idle/in-gear/coast down as clam as can be. Is this an area to deal with?

PRE-Z06

Won't you actually be running leaner with e20 untuned for it?

SpinMonster

As I stated earlier, your car is now running E10 and it isnt tuned for it. If you tune for E10 as you should, and you run E20, you're in the same boat.

All cars running E10 are running lean LTFT's but the car can compensate for this percentage. It runs richer in WOT/PE mode. We see this all the time when cars go in for a tune bone stock. Its in the 11's:1.

Yes you need to tune for E20 to see the power gains. 1 gallon of E85 or E70 per 5 gallons of gas will let you run 3-4 degrees more timing. I gave the stoic and PE values to tune for it.

SpinMonster

More timing smooths out the idle as does running richer. If you have E10 in the tank and you run the stock stoic value, its a leaner trend. Although the PCM holds you at stoic, the values vary in a range. The stoic value being corrected to 14.15 makes the variance centered on a lower stoic. For example, if you have 14.7 as stoic your wideband may show 14.4 to 15.3 as the trend. If you set the stoic at 14.15 then the trend will center at that stoic say 13.8 to 14.5 instead. The car has the most lope when the mix is leaner over 15 being corrected. Your wideband will always show the same range since its reading lambda. If you program the wideband to show 14.15 as stoic you will see the shift down and will see 13.8 to 14.4 or so.

The idle table should be higher than the 19 degrees it has. The engine isnt under load and it has no effect of producing knock if you set it higher to 25 or so.

0Myhardtop

This is good information Mr. SpinMonster.

Here is the approach I took with my cammed C6Z06.

On E85, I simply scaled back my 60 injectors in this table:
Injector Flow Rate vs. KPA VAC I reduced the entire table by 30% and did not mess with the stoic table it all. I just trick the ECU if you know what I mean

I tuned for best A/F on the dyno by reading my on-board A/F meter and the tail pipe dyno prong...my fuel is adjusted to a commanded 12.4 A/F. I found best power with this approach and with TR55 instead of TR6

My Cammed Z made a best of 604rwhp using one of my cams, bolt ons and STOCK HEADS!!!! Like you mentioned, as far as timing, I tweaked the spark tables for the E85 tune off my best 93oct spark tables tune...I only added 2* degree of timing on top and at torque peak and 3* on the bottom.

The car did not make any additional power with more timing or fuel, so this is where she likes it. Keep in mind that my big cammed Z lost a little dynamic compression and we all know how much E85 loves compression. I tossing the idea of removing the head for milling and then go from there. My avg runs on 93oct were 584/535 and on E85 593/544 or so. My solid best pull on 93 was 588/537 vs my best E85 604/555...I'm on the E85 wagon all the way and the car runs cooler, cleaner and it even smell sweet.

What are your thoughts?

This is good stuff

Thanks,
Carlos

SpinMonster

Fuel mixing.

In general the octane response will be linear for most hydrocarbon and oxygenated fuels eg 50:50 of 87 and 91 will give 89.

A situation where it doesnt work was back when we had leaded fuel. Attempts to mix leaded high octane to unleaded high octane to obtain higher octane are useless for most commercial gasolines. Some blends of oxygenated fuels with ordinary gasoline can result in undesirable increases in volatility due to volatile azeotropes, and some oxygenates can have negative lead responses.

In our case the mix of E10 and E85 are already related to each other in make up with ethanol/gasoline ratio being the only variable. Additives and such by brand may vary but in the case of filling up, you have to do both at the same time at the same station anyway. You mix 5:1 and its best to mix them at those intervals. I would tune the stoic upon filling and the dyno tune only after a few days and refueling again to assure the proper mix. If you completely drain the tank, fill the E85 first so the initial slug into the fuel lines is a mix of more E85 to the small amount of gas or E10 already in there.

SpinMonster

I dont recomend not entering the proper stoic value. You didnt save any time/effort doing this.

The purpose of making the stoic value 9.76 is that the WOT a/f desired value is divided into this value to get you the percentage you need. The sotic value of 9.76/your desired PE gives you the proper value for the PE table. For example if you want a WOT a/f ratio of 13:1 with gas, you use 14.7/13= 1.13. E85 actually produces more power being richer. So a stoic of 9.76/8= 1.22. Its as if you are 12:1 on gas.

Your gains are in line although I would expect higher since retuning on torco would get you that at only 97 octane.

If you richened up by running the injectors with a smaller value, you are not letting the car run right in closed loop by centering the stoic. In closed loop fueling where it uses the O2's to measure fueling referencing the stoic value, you car should be showing -30 LTFT's, because the stoic is too high.

Its just as easy to enter the proper value for stoic instead of tricking the PCM and doing it wrong. Many other values for the engine come from running the correct stoic value. Its a 60 second change.

NOSLO6

Great post. Has the hallmarks of a truly great idea-- highlights an obvious point that is easy to do, but is (for no good reason) rarely done.

A few of the Buick folks I run with have been doing this for a while now and yes it does matter. Every little bit helps. I run E85 in the GN, but as you point out we're all running E10 nowdays...

shizon'00

OK....

1) I never said you said E20 = E85 octane. Please quote where I said that.
2) I said blended octane does not equal AKI or R+M/2 (which is what the US uses at the pumps). I'll give you some reading so you can catch up on that in real testing with ethanol. Start on page 5. There are other reasons, besides octane, why E85 gives such a nice power pump (as powerlabs so correcly pointed out).
http://www.ethanolrfa.org/resource/t...pdatedLogo.pdf
3) I'll stay out of the personal attacks because I really think your intentions are good. Please do the same. If you see a problem with my question/argument point it out and refrain from the "you're on your own" type passive aggressive comments. I think your processes are flawed and you posted before you have real results.
4) You don't have any proof that E20 adds power except you can run more timing which sometimes loses power on a dyno (max timing doesn't always equal max power). There's a couple of reasons that you can run more timing on E85 without knock sensor activity.
5) Maybe you should clarify what kind of power levels are going to get roughly double the hp benefit of a tune that you made. I see roughly 5-6% increase on an n/a car running E85 over E10. You are claiming about the same amount of hp (4% on a stock car) in only a 10% increase in ethanol content. That's going to raise my eyebrows and ask for how you got to those numbers. Your response is butt dyno and spinning tires. I was expecting track times or dyno numbers.

I get tired of the ethanol nay sayers putting out info on how it's going to eat up fuel systems etc without solid proof and I'm going to hold you to the same standards. You acted like my first question was not legitimate and uninformed. Let's start there.

And yes, I obviously didn't teach you everything you know. I never said I did. Heck, maybe nothing I said helped! You're a smart guy and asked others also which you should. Open minds is how progress is made and I hope you can keep an open mind about your own claims as much I will. I never said this isn't possible, I just asked for proof on your claims and I got a response saying I don't understand octane.

shizon'00

This is not correct. If he scaled his injectors and all other things were correct on gas before the scaling, the car will run correctly changing fuel without ltft's. Because of the scaled injectors, the pulsewidth will increase the same scaled amount accounting for the missing fuel from the fuel type change. O2's will see the correct lambda and switch normally with normal amount of corrections with the ltft only being the margin of error between fuel compositions.

However you are correct that scaling injectors is the incorrect way to do it. Changing stoich is the correct way.

SpinMonster

I have not been disrespectful from the beginning. Its you who came in here and made the bigger bold statements.

As far as not having results, higher octane does raise power levels as many tuners have posted lots of real data. RPM's results with meth injection and tuning on torco case in point. I hope you have seen how octane adders like those in fact improved dyno gains. Meth injection also improved Phil Jimenez' NA car by 25rwhp. If we can agree that octane boosters do in fact have HP gains on a dyno, then I guess the only point we differ on is if E85 in various amounts mixed with E10 increases octane. We also agree that E85 does in fact increase octane and performance. And we differ greatly on this point of mixing for octane gain. Is 50-50 a gain? The oxygenated fuels we run in our cars especially E10 and E85 are in fact additive in octane and it rises linearly. It is very much A+B/2. My research last night said that it is a linear gain and it is for all of these types of related fuels and E10 is certainly related to E85. We are not talking about combining Avgas with leaded premium in 1975.

If you choose to believe that octane isnt rising if you run x-gallons of E85 along with E10, you're wrong and you're entitled to do what you want. I dont want anymore reading as I have done enough. I welcome you to go into your links and find exact formulas to tell me what a 50-50 mix of E10 at 93 and E85 at 105 octane will be. I'll look at that in this thread.

I proposed an idea. Higher octane increases power. The first car was a trailblazer SS running the stock timing curve and it was pulling 4 degrees timing. We added 1 gallon E85 to the 5 gallons of E10 and the knock was gone plus it ran 23 degrees instead of the 19 it had stock. The octane did rise there.

If someone can be coaxed into springing for a dyno tune instead of the free street tunes, I'm in and will share the info. Until then, I wouldnt bet the house that the power isnt rising. While I dont have Tyler's garage's dyno cache, I will tell you that he said he has yet to see it not produce 30hp on a 400hp car. I didnt think it was that important that someone would get so put off by it.

Lets keep in mind that I'm not selling anything here. Like the free cam specs I toss out, this info is for DIY guys to run with and report back what they get. A rolling demo of all my mods is Phil Jimenez's car which has every mod I ever came up with from N/A meth injection to the tractionmonster mod. They all work. Do what you will with this one but its a matter of time that I will get the 'proof' you will accept but until someone else funds it, I'm done footing the bill for free R&D.

Want to donate 125 for a 1/2 hour dyno time? I'll do my friend's GTO this coming week on a dynojet. Bone stock first, then add the E85 tune. Till then, do the math and get back to me on what the octane of E20 is.

SpinMonster

OK, I never tried it that way so I'll accept it.

shizon'00

I think that says it all Jay.

For everyone else, I would encourage you to go and look at the link I posted about octane and ethanol. Again, you don't have to read all of it, just page 5 where they actually did the testing and got an octane rating of 94-96 based on their math and real AKI testing.

I'd love to see Tyler's dynos on E10 vs E20. Maybe he can post them up here or send them to you to post up? Again, E10 vs E20, not E85. I'm fully aware of the benefits of E85 in all kinds of applications.

SpinMonster

It wasnt what I said either. I said a car tuned with more octane makes mnore power. I showed a chart of varying ethanol amounts to make octane rise. A car has a limit to the octane it needs thus using 96 on some cars will hit the peak and running 105 wont increase it....thus to save fuel system capacity, reduce ethanol content to run the octane amount you need.

SpinMonster

You have me confused with my brother Jay, I'm Guy. You can pick out Jay because he is not wound as tight as a drum as I am.......other than that we look strikingly alike.

OK, finally you extracted the info I was supposed to go read. OK now with that out of the way, this article claims that ethanol isnt 105 octane as it is widely advertised by about a million sources and its actually 94 to 96. If a dyno reveals a gain of 15rwhp over a fully tuned base car with E20 added, what would be the conclusion?

I guess the government's weights and measures are a bit off.

SpinMonster

To this I can respond. When an N/A car is tuned, there is a max timing and optimum fuel curve it will produce that no amount of octane can overcome. If a given engine that you tune on E85 didnt need all of its benefits then less octane for example could have gotten the same effect. Logically cant we conclude that maybe 94.5 octane rather than 96 hit this optimum level and running 115 wont top it? In other words you may have been able to hit the same gain on 1/2 or 1/4 of a tank of E85 and still gotten the same power gain.

I think we can agree yes.

In the case of ALL the cars tuned at Tyler's shop, they are all big boost cars and E85 has another big effect on boosted cars. They are 2 liter motors running maxxed out turbos with lots of boost pressure. Here E85 would make a bigger impact. The same engine running 700AWHP would be running a huge turbo and 42psi. The octane requirements arent the same. Hence on the lower powered cars to run less injector and less fuel pump, they limit the fuel flow requirement by adjusting E85 levels down. Tuning 160lb injectors is the issue they want to avoid. Remember thats 4 cylinders making 700hp.

In the LS engine world, H/C cars arent running the max ever because our efficient cylinder heads make huge power with less spark. Cars with optimum compression make great power gains compared to cam only cars with lower dynamic compression. Trying to give an average of what various cars with various mods will gain on a given octane is silly. No amount of octane in a honda accord will gain anything more from 94 than 100octane. Hence why some cars make big power and others make the same numerical gain on less octane. Without optimizing the engine to take advantage of it, you cant say onne octane size fits all.

I'll get some data to you because you sparked my interest.

Respectfully.

I did feel attacked earlier with your first post....its all good.

shizon'00

It actually talks about the difference between blended octane (what everyone on the internet is quoting, hell even me most of the time) and AKI which is real Anti-Knock Index octane rating. Worth a read.

I wouldn't have a conclusion immediately. After a repeatable baseline, I would probably first put the E20 in, adjust fuel, and dyno it to see what if any gains happened. Then start to increase spark.

If I see a gain with the same spark, that would hint at an increase due to a cooling effect of the charge in the manifold and oxygenation, not octane.

If I see a bigger increase after increasing spark a little, I would probably be lead to think that the increase in power was because of a combination of increased octane and cooler charge and oxygenation and the difference could be roughly estimated. I would expect a small decrease in power from a higher octane fuel without the spark change as MBT is no longer correct.

That's how I'd setup the experiment off the top of my head anyway.

shizon'00

I agree with your question, but not your assessment after that. I think you are discounting the other benefits of an oxygenated fuel and it's cooling properties and giving all the credit to octane improvement. Thus you may see a bigger improvement with a larger concentration of ethanol because of the other benefits. Both of our arguments are theory at this point because neither of us have done the testing with E20 on a dyno.

I understand what you're saying, but I also don't know that octane is the 100% cause of it. I believe it's a player. I believe the cooling effect is a slightly larger player in the power increase though because of the higher air temps of a boosted car. That's just from my experience between E85 and race gas however haven't had the opportunity to test both on the same car. This would be a good experiment. 93 gas vs 104 gas vs E85. I would guess E85 outpowers the 104 gas. Would need to do the testing though.

You didn't specify the setup under which you saw these gains in your first post. I'm just trying to get clarification.

Cool

Sorry. That's why i posted in my first post I hope it doesn't turn into a flame war. It was not my intention at all.