95GSRTT

I have a question for all of you tuners out there. I was wondering if any of you have run into a problem with pump gas tunes in the areas where they are now adding more ethenol to pump gas. Up to another 15% apparently in some areas.

Hopefully someone can shed some light on this for me. I have heard some rumors of tuners going as low as a 10.0 a/f and the car making great power where it should be breaking up and being too rich to really spark.

Has anyone else had this problem?

95GSRTT

bump

SOHC_MShue

Ethanol has a much lower stoich AFR than pump gas so yes the correct afr's are going to be much lower. For fuels like that its easier to tune in terms of lambda imo or you can setup the wideband to read pump gas afr's so for instance if you are at the stoich afr for ethanol it will still read 14.7:1 when in reality it is much lower, but since the o2 sensor actually reads oxygen content and not air:fuel then it is fine to tune that way.

To tell you the truth I have seen no noticable change in my tune running this new 10% ethanol stuff. I really thought there was gonna be a change. Theoretically the car should run leaner and require more fuel, but there is already a certain percentage of ethanol in pump gas anyways. What i'm really interested in though is this E85 stuff. When is that gonna be readily available?

95GSRTT

bump

95GSRTT

nothing from anyone?

SOHC_MShue

lol i already gave you the answer to your quetion. Ethanol has a much lower stoich afr so you need to run much lower afr's period.

david@didrace.com

In Illinois they add up to 10% ethanol to gasoline. So you'd be going from a stoich of 14.7 to roughly 14.1 (provided the ethanol's stoich value is around 9.0:1).

Never really noticed a big difference at WOT. Ethanol has better cooling characteristics and a higher octane value so I would figure that would make up for the slight variance in it possibly running leaner and still being safe. I've tuned a bunch of N/A LS1/LS6's to 13.5:1 at WOT making best power there and haven't had issues with detonation or anything. And even the E85, I've seen tests on GM vehicles were they'll run 100% gasoline and get say 18mpg, switch to E85 and only loose 1mpg. So obviously you can run ethanol at a leaner Lambda than you can gasoline and still be safe. Much like running some race gases, just because of the higher octane you can run them WOT at or near stoich and make peak power.

tony1

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by backpurge &raquo;</TD></TR><TR><TD CLASS="quote"> Much like running some race gases, just because of the higher octane you can run them WOT at or near stoich and make peak power.</TD></TR></TABLE>

You know stoich is not where peak power is made, right?

95GSRTT

I know I know and I got that. I was more looking to see if any other tuners have had a problem with this. Or maybe someones car has blown because the car was based on a former tune and then when the owner put in this new gas with higher amounts of ethonal the a/f was way off and kablooey.

david@didrace.com

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony1 &raquo;</TD></TR><TR><TD CLASS="quote">You know stoich is not where peak power is made, right? </TD></TR></TABLE>

Typically it's not but it can be.

I have a dyno run on our computer that shows maximum power drops off from 1 to .95 lambda running on Sunoco Maximal.

I can post it up if you want.

95GSRTT

So is this going to be a problem for current modified owners? Going from a bigger amount of oxygen in the gas different that is used, and the tune that was set up for the car, will people need to get retuned? or should the car compensate for over 2.0 drop in a/f?

david@didrace.com

Tune on 10% ethanol then it'll just run richer on 100% gas.

SOHC_MShue

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 95GSRTT &raquo;</TD></TR><TR><TD CLASS="quote">So is this going to be a problem for current modified owners? Going from a bigger amount of oxygen in the gas different that is used, and the tune that was set up for the car, will people need to get retuned? or should the car compensate for over 2.0 drop in a/f?</TD></TR></TABLE>
If you switch to E85 retuning is an absolute must along with probably getting larger injectors if you dont already have oversized injectors for your application.

david@didrace.com

I don't believe he's talking about E85, he's talking about the 10-20% ethanol added gasoline blends offered in some state's gas stations, but you're right.

95GSRTT

Ya Im talking about the 10-20% added. So from what you are saying, IF the cars were already tuned on regular gas before the switch they could definitely run very lean and end up detonating and blow correct?

david@didrace.com

There's a possibility. On some vehicles, GM's for example, you can wire up a wideband in place of a stock narrowband and have using various pieces of software tell the ecu to have a target lambda at WOT so no matter what you get the correct a/f for X fuel that is being run. The AEM EMS and other standalones can do this too. I usually just tune in a fairly safe margin if the customer isn't wanting every last little bit of HP.

SOHC_MShue

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by backpurge &raquo;</TD></TR><TR><TD CLASS="quote">I don't believe he's talking about E85, he's talking about the 10-20% ethanol added gasoline blends offered in some state's gas stations, but you're right.</TD></TR></TABLE>
ahh **** i forgot we were talking about the low mix of ethanol gas. Like i said i've tested regular gas vs. this 10% stuff they got at the pumps now and didn't notice any notable change in afr's on 2 seperate cars. Theoretically there should be a change, but gas has had a small percentage of ethanol in it already for a while. I definately wouldnt hesitate to check your tune though.

10secivic

Here in the nw it gets pretty bad, especially with the rotary motors ( one knock blows seals). We usually retune cars for the two stages of gas the state uses.

Suprdave

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by backpurge &raquo;</TD></TR><TR><TD CLASS="quote">Typically it's not but it can be.

I have a dyno run on our computer that shows maximum power drops off from 1 to .95 lambda running on Sunoco Maximal.

I can post it up if you want.</TD></TR></TABLE>

I honestly can't think of any situation where a car at WOT will make more power at Stoich. Turbo Cars will melt or misfire if you tune them at stoich...

All-Motor Cars wont make more power at stoich either...If you lost power from 1 to .95 Lambda, something else changed other than just the ammount of fuel.

david@didrace.com

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Suprdave &raquo;</TD></TR><TR><TD CLASS="quote">

I honestly can't think of any situation where a car at WOT will make more power at Stoich. Turbo Cars will melt or misfire if you tune them at stoich...

All-Motor Cars wont make more power at stoich either...If you lost power from 1 to .95 Lambda, something else changed other than just the ammount of fuel.</TD></TR></TABLE>

Nope, we threw bigger jets in it and it lost power. All of the max. torque at lean/rich a/f #'s are theoretical. Like I said above, I've run a bunch of LS1's past the lean best of 13.3, to around 13.5/13.6 and made best torque. With the Sunoco Maximal being only around 25% actual gasoline and right around 75% additives it might have a different lean best torque a/f ratio.

Alot of it has to do with how efficient some motors are versus others. Most heads/cam LS1's I've done easily reach 105% VE no problem, where as you can only get around 95% on heads/cam modular Ford. And with that, I'm able to run the LS1's leaner, safely and make more power.

Lean and mean.

Suprdave

Well the Stoich of Gasoline is 14.7:1...

So you are agreeing with me, right David

david@didrace.com

Not exactly, I agree that with gasoline running WOT at 14.7 is just an accident wating to happen, but... I have seen certain instances with some fuels you can make best power at a Lambda of 1, safely. I think the stoich a/f of that Sunoco Maximal was like 17:1 off the top of my head.

And on another note... where do your website go?

Suprdave

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by backpurge &raquo;</TD></TR><TR><TD CLASS="quote">Not exactly, I agree that with gasoline running WOT at 14.7 is just an accident wating to happen, but... I have seen certain instances with some fuels you can make best power at a Lambda of 1, safely. I think the stoich a/f of that Sunoco Maximal was like 17:1 off the top of my head.

And on another note... where do your website go? </TD></TR></TABLE>

I've never messed with that Sunoco Maximal stuff you are talking about...whats the octane? And I screwed up my website messing with the server thing and now it doesn't work...

david@didrace.com

http://www.sunocoinc.com/Site/...l.htm

Anti-knock Index of 116 Octane, Leaded. Used two different brand new O2 sensors to verify Lambda.

Screwed up your own server, and they let you use a computer to tune cars over there?

Suprdave

So that's basically C16 with a really low specific gravity...

You can always tune stuff like that to a leaner AFR...

You can get away with tuning for max power on NA Setups without really worrying about melting anything. Racegas is incredibly forgiving and you can really bone up the tune and you wont really ever notice.

When it's forced induction and pump gas the rules change and you are forced to try and keep heat down and the engine together. Example: B18C1, 350whp, Pump Gas, Reliable...