E85

[imagine]

Hi, '14 TA w/ Arrow PCM, drop-in filter, and 2 cats removed. I'm considering adding a couple gallons of E85 to my usual 93 fill-up. I do this on my Audi 3.0 V6 supercharged & 93 pump-tuned car - seems to run really well. Just wondering if 1) the Gen V is capable of running E85 (believe most cars post mid-2000s support at least some ethanol-based fuel) & 2) if the consensus is that it'll perform as expected. I live in South FL and both of my Vipers have experienced pinging. The 06 I had was basic bolt-ons and a 200 wet shot, but I always ran a mix of Sunoco unleaded 93/100 in the tank as a safety margin. Cleared up the pinging and performed well. Thanks in advance for the feedback.

[Snorman]

No.
S.

[99RT10]

Actually, there is a case for doing a 70/30 mixture which will increase your octane level and produce more power. The imports do this a lot to gain power:

http://www.1addicts.com/forums/showthread.php?t=862583

[nx91notch]

I don't see why this is needed. I live in the Tampa/St. Pete area of FL. I have ARH long tube headers with high flow cats with the Arrow PCM. I run pump 93 fuel and never have had any issues with pinging.

Maybe Tampa steals all the good fuel and sends the leftover junk to South FL ;)

[CarolinaViper]

Actually, there is a case for doing a 70/30 mixture which will increase your octane level and produce more power. The imports do this a lot to gain power:

http://www.1addicts.com/forums/showthread.php?t=862583

If the engines are factory tuned to run on 91 Octane - would increasing the octane level without a new tune do any good.

[99RT10]

The OP stated he was experiencing pinging. With an E25-E30 mix, the car will see a higher octane level eliminting the knocks and pings. I don't do it, but there is a case for it.

[Snorman]

Actually, there is a case for doing a 70/30 mixture which will increase your octane level and produce more power. The imports do this a lot to gain power:

http://www.1addicts.com/forums/showthread.php?t=862583
You have to be tuned for it or the car will lean out. E85 has less energy per a given volume compared to 93 octane, so it needs MORE volume. Adding E85 without a tune could be dangerous IMO.
S.

[imagine]

E85 is higher octane & a cooler burning fuel compared w/ pump. Stoich is different, etc etc - in theory any car that is pinging, pulling timing can benefit from higher octane, regardless of the map. I'm just wondering if anyone here has real world experience w/ this. I'd compare it to the 100 unleaded and that worked, but was very expensive. Not apples for apples, but as mentioned on my pressurized DD on a 93 map, mixing in a couple gallons of E85 has already made the car feel sharper & more consistent. I'll need to pull some logs soon.

[Jack B]

If the engines are factory tuned to run on 91 Octane - would increasing the octane level without a new tune do any good.

You will typically run richer at wot when running a higher octane fuel. The actual resultant a/f depends on the stoic number of the mix.

For the OP how can you hear pinging with no cats

[dewilmoth]

There's so much bad info in this thread it's comical. Willy nilly throwing some e85 in the tank to improve octane rating is probably not wise. The motor will run significantly leaner with ethanol, and how much is too much, is anyone's guess.

I'm a huge proponent of E85, especially in FI motors that have been tuned for it, but this isn't that.

[99RT10]

^^^Well there dude, enlighten us :rolleyes: ^^^

http://www.viperalley.com/forum/viper-discussions-gen-i/263337-30-ethanol-fuel-stock.html

These cars do run rich. If you click on the link above you will see real world results. But you have to dyno check the car if planning on running this mixture to make sure it's safe.

[ACR]

The closed loop nature of the pcm / o2 will add more fuel when afr is lean, so in theory you can add a little more ethanol to the fuel. However, how much is undetermined because of injector and fuel pump capacity

[Jack B]

He thinks he knows more than the rest of us, but, in fact has shown something else. I am going to paste an old racing forum post into this thread that is an interesting read if you are concerned about the impact of fuel octanes on a tune.



^^^Well there dude, enlighten us :rolleyes: ^^^

http://www.viperalley.com/forum/viper-discussions-gen-i/263337-30-ethanol-fuel-stock.html

These cars do run rich. If you click on the link above you will see real world results. But you have to dyno check the car if planning on running this mixture to make sure it's safe.

================================================== ========================
Race Gas Stoich Rating Tuning Considerations

Well I have seen questions from time to time about adding race gas without tuning which can be a very expensive experiment. I am going to explain how stoich effects AFR. Hopefully in simple format.

I am not going to get into MAF transfer functions or other tuning functions.This is just about fuel.

First lets define a few terms:

AFR: Air Fuel Ratio

Stoich Rating: In simple terms is the AFR to have chemically complete combustion that is neither rich or lean. For Example most pump gasoline is about 14.64 to 1. Which means 14.7 parts of air to 1 part of fuel.

Lambda: Is a term that is utilized when tuning. In basic terms think of it as an adjustment to your stoich rating when tuning AFR. For example with pump gas tuning .80 lambda, 14.7 x .80 = 11.76 AFR target.

Lets assume your car blower car has a nice tune that gives a perfect 11.8 AFR under WOT with pump gas.

So now it is race day. We add some timing to our tune, drain the fuel tank, and fill up with some high octane unleaded VP109.

We go for a blast down the 1/4 mile while datalogging and see the A/F is reading 12.8 then make a quick trip to the bathroom only to find out they are out of toilet paper -lol.

There are a few factors here to consider.

The stoich rating of VP109 is 13.41.
Most wideband A/F modules are calibrated to 14.7 pump gas stoich.

So this is the formula to determine the true A/F for the run.
AFR/Wideband Stoich x Race Gas Stoich
12.8/14.7*13.41= 11.7 AFR on Race Gas

So you may think 11.7 sounds safe but we must remember the VP109 stoich is 13.41. So 11.7 AFR = .87 lambda. For the most part a safe lambda value is .80 to .82 for a forced induction mustang. I prefer .80

So we take VP109 stoich of 13.41 x .80 lambda = 10.73 AFR
This is the AFR (10.73) I am tuning for.

Keep in mind this is not what will display on your wide band as it is programmed to 14.7 stoich. You must convert the AFR.
================================================== ========

[imagine]

You will typically run richer at wot when running a higher octane fuel. The actual resultant a/f depends on the stoic number of the mix.

For the OP how can you hear pinging with no cats

The 06 I picked up was a 1 of 50 red/white stripes coupe w/ 250 miles. Heard pinging from day one both stock and with a 93 NA tune. I switched to a 93/100 mix, which resolved the pinging. I then removed 2 of the cats and went with the 200 wet setup and kept the same 93/100. Didn't have any issues with this setup.

On the 14 TA, it came w/ an Arrow PCM but otherwise stock. The first owner had headers/exhaust on the car and pulled them off prior to selling. Again, same thing - could hear mild pinging up top, especially on the initial run. Seemed to clear up on subsequent runs. I've since added a K&N drop-in and had the 2 cats removed. Haven't put a lot of miles on it since, but the car is running cooler and I haven't heard pinging in the few quick blasts I did.

[Jack B]

What gear and what type of load?


The 06 I picked up was a 1 of 50 red/white stripes coupe w/ 250 miles. Heard pinging from day one both stock and with a 93 NA tune. I switched to a 93/100 mix, which resolved the pinging. I then removed 2 of the cats and went with the 200 wet setup and kept the same 93/100. Didn't have any issues with this setup.

On the 14 TA, it came w/ an Arrow PCM but otherwise stock. The first owner had headers/exhaust on the car and pulled them off prior to selling. Again, same thing - could hear mild pinging up top, especially on the initial run. Seemed to clear up on subsequent runs. I've since added a K&N drop-in and had the 2 cats removed. Haven't put a lot of miles on it since, but the car is running cooler and I haven't heard pinging in the few quick blasts I did.

[dewilmoth]

He thinks he knows more than the rest of us, but, in fact has shown something else. I am going to paste an old racing forum post into this thread that is an interesting read if you are concerned about the impact of fuel octanes on a tune.




================================================== ========================
Race Gas Stoich Rating Tuning Considerations

Well I have seen questions from time to time about adding race gas without tuning which can be a very expensive experiment. I am going to explain how stoich effects AFR. Hopefully in simple format.

I am not going to get into MAF transfer functions or other tuning functions.This is just about fuel.

First lets define a few terms:

AFR: Air Fuel Ratio

Stoich Rating: In simple terms is the AFR to have chemically complete combustion that is neither rich or lean. For Example most pump gasoline is about 14.64 to 1. Which means 14.7 parts of air to 1 part of fuel.

Lambda: Is a term that is utilized when tuning. In basic terms think of it as an adjustment to your stoich rating when tuning AFR. For example with pump gas tuning .80 lambda, 14.7 x .80 = 11.76 AFR target.

Lets assume your car blower car has a nice tune that gives a perfect 11.8 AFR under WOT with pump gas.

So now it is race day. We add some timing to our tune, drain the fuel tank, and fill up with some high octane unleaded VP109.

We go for a blast down the 1/4 mile while datalogging and see the A/F is reading 12.8 then make a quick trip to the bathroom only to find out they are out of toilet paper -lol.

There are a few factors here to consider.

The stoich rating of VP109 is 13.41.
Most wideband A/F modules are calibrated to 14.7 pump gas stoich.

So this is the formula to determine the true A/F for the run.
AFR/Wideband Stoich x Race Gas Stoich
12.8/14.7*13.41= 11.7 AFR on Race Gas

So you may think 11.7 sounds safe but we must remember the VP109 stoich is 13.41. So 11.7 AFR = .87 lambda. For the most part a safe lambda value is .80 to .82 for a forced induction mustang. I prefer .80

So we take VP109 stoich of 13.41 x .80 lambda = 10.73 AFR
This is the AFR (10.73) I am tuning for.

Keep in mind this is not what will display on your wide band as it is programmed to 14.7 stoich. You must convert the AFR.
================================================== ========

This thread is about adding E85 (a form of alcohol) to the tank to increase octane, not adding high octane gasoline. They're very different fuels, and the difference isn't just their octane level. My ego doesn't require that I get in a pissing match with you, but you're wrong, and your copied reference isn't pertinent to this thread. E85 has roughly 30% less energy per given volume, requiring 30% more flow through the injectors to get the same Stoich. I saw it mentioned that the closed loop PCM will fix the requirements with fuel trim, but the PCM is only closed loop during part throttle cruising. At WOT it pulls values from a chart, and thus, the car will run quite lean. How lean is anyone's guess without using a wideband O2 sensor, but it will definitely be more lean than with E15. Bottom line, either tune the car for E85, or use high octane gasoline if you're convinced you need higher octane on the stock PCM (that's a whole different discussion), but don't assume that adding ethanol to the tank is only increasing octane without other ramifications, because it isn't.

I'm just trying to save someone from grenading their expensive motor, but doesn't really matter to me at the end of the day. The guys asked a question, and I gave an answer. Carry on, you're the expert.

[Bruce H.]

From tuning discussions on a different platform it was well accepted that in order to enjoy the higher octane and tuning benefits of using E85 required upgrading the fuel system to deliver the higher volume of fuel necessary compared to simply running a higher octane fuel mix at the same power levels. The increased fuel volume was always an issue to compensate for. The professional tuners there were getting something like 800 rwhp from 2.4 litres on it.

[Jack B]

My comments followed the posts relating to mixing with higher octane fuels, you are using selective misdirection in trying to back up a poorly worded and placed post. BTW you are missing the point that the an O2 sensor calibrated at 14.62 will not read correctly for a diff stoich (mixed fuels), this is important if you have an embedded wide band or on the dyno, read that article again.


This thread is about adding E85 (a form of alcohol) to the tank to increase octane, not adding high octane gasoline. They're very different fuels, and the difference isn't just their octane level. My ego doesn't require that I get in a pissing match with you, but you're wrong, and your copied reference isn't pertinent to this thread. E85 has roughly 30% less energy per given volume, requiring 30% more flow through the injectors to get the same Stoich. I saw it mentioned that the closed loop PCM will fix the requirements with fuel trim, but the PCM is only closed loop during part throttle cruising. At WOT it pulls values from a chart, and thus, the car will run quite lean. How lean is anyone's guess without using a wideband O2 sensor, but it will definitely be more lean than with E15. Bottom line, either tune the car for E85, or use high octane gasoline if you're convinced you need higher octane on the stock PCM (that's a whole different discussion), but don't assume that adding ethanol to the tank is only increasing octane without other ramifications, because it isn't.

I'm just trying to save someone from grenading their expensive motor, but doesn't really matter to me at the end of the day. The guys asked a question, and I gave an answer. Carry on, you're the expert.

[dewilmoth]

My comments followed the posts relating to mixing with higher octane fuels, you are using selective misdirection in trying to back up a poorly worded and placed post. BTW you are missing the point that the an O2 sensor calibrated at 14.62 will not read correctly for a diff stoich (mixed fuels), this is important if you have an embedded wide band or on the dyno, read that article again.

Like I said, you're clearly the expert in a thread titled "E85".

[imagine]

What gear and what type of load?

WOT, typically in 2nd & 3rd gears. On the 06 - anywhere from mid to high revs. On the 14 - mainly above 5500rpm. I usually back out of it when I hear it.

[Snorman]

From tuning discussions on a different platform it was well accepted that in order to enjoy the higher octane and tuning benefits of using E85 required upgrading the fuel system to deliver the higher volume of fuel necessary compared to simply running a higher octane fuel mix at the same power levels. The increased fuel volume was always an issue to compensate for. The professional tuners there were getting something like 800 rwhp from 2.4 litres on it.
Bingo, Bruce.
It doesn't matter what the effective AKI or RON of E85 is. The lower specific energy of E85 vs. typical pump (or race) gas blends is the problem. The PCM will NOT compensate for this and depending on how much E85 has been mixed into the tank the tune can go lean and damage the engine.
E85 compatible cars already have the hardware needed to run various mixes or blends of E85 including an ethanol sensor to determine what blend of fuel is in the fuel tank.
The OP should not be putting E85 in his car to help with "pinging". He should be mixing in either higher octane pump or race gas or have his tune addressed.
E85 will make big power on forced induction applications because it burns "cooler" (due to increased volume) and has a higher AKI. In fact, it'll make about as much power as C16 without all the crummy side effects (leaded fuel, no cats, stinky exhaust, etc.) because of this.
S.

[Jack B]

That is unusual, in general if you are going to get knock it will happen at peak torque, the G5 is approx 5200. The factory tune on the G5 does not have an aggressive advance curve. If the AIT temp is under 87 deg you have approx 16 deg advance at peak torque. If the AIT is over 87 Feb, you could have as little as 10 deg advance.

Maybe someone else has some input, but, it seems like there is more happening than just knock.




WOT, typically in 2nd & 3rd gears. On the 06 - anywhere from mid to high revs. On the 14 - mainly above 5500rpm. I usually back out of it when I hear it.

[ViperSRT]

Stoichometry for gasoline and ethanol blends.

Gasoline. 14.7:1
10% Ethanol Gas. 14.04:1
15% Ethanol Gas. 13.79:1
E85. 9.75:1
Pure Ethanol. 9:1

Clearly the O2 sensor and the PCM will acurately determine fuel adaptives at part throttle, given the sensor is reading lambda and not a/f ratio (regardless of what your gage states it is reading lambda). Lambda =1 is true no matter what the fuel chemistry. Fuel tables at WOT will be incorrect based on the volume flow requirement differences, which are approximately 40%. The 30% number indicated above is with constant power, but E85 contains about 16% more energy than Gasoline when both are at stoich ratios. Thus you must have much greater fuel flow to avoid lean conditions. Or wait for the pistons to inform you that they are not happy anymore.

[Jack B]

Lambda and a/f are directly linked. If the O2 sensor cannot read a/f, it cannot read lambda correctly. When you deviate from 14.7, stoich, you have to re-calibrate (or compensate thru the tune) the O2 sensor for the new stoich. I run an Innovate wideband and it has a menu for different stoich values. Without a re-calibration It will read, however, the true a/f will be off by the percentage difference between the actual stoich and 14.7. The difference is not bad for some fuels, but, the 110 and higher there is a considerable difference in stoich. This is sort of complicated and we have not interjected the higher oxygen content in some fuels with higher octane.

With a fixed tune there is nothing we an do about it, however, if you have HPT or a stand-alone you can compensate at wot for the other than 14.7 stoich fuels. What is bad, the viper factory tune runs extremely rich on the dyno. I do not know why, but, I have done three dyno sessions with my G5 and they were off by one full point at the track (versus the dyno), the track running leaner.


Stoichometry for gasoline and ethanol blends.

Gasoline. 14.7:1
10% Ethanol Gas. 14.04:1
15% Ethanol Gas. 13.79:1
E85. 9.75:1
Pure Ethanol. 9:1

Clearly the O2 sensor and the PCM will acurately determine fuel adaptives at part throttle, given the sensor is reading lambda and not a/f ratio (regardless of what your gage states it is reading lambda). Lambda =1 is true no matter what the fuel chemistry. Fuel tables at WOT will be incorrect based on the volume flow requirement differences, which are approximately 40%. The 30% number indicated above is with constant power, but E85 contains about 16% more energy than Gasoline when both are at stoich ratios. Thus you must have much greater fuel flow to avoid lean conditions. Or wait for the pistons to inform you that they are not happy anymore.

[ViperSRT]

The calibration is only to make an air fuel ratio increment gauge to read correct for a given fuel. The O2 sensor provides a voltage output related only to lambda. Lambda measurement is fuel insensitive and no O2 sensor calibration is required for the fuel. Most O2 do have a free air calibration procedure unrelated to the fuel. In other words if you change fuel from E0 to E85 with a a/f reading gauge it will show around 14.7 even though the actual a/f ratio changes significantly. Best to have the gauge read lambda as that is what it measures.

[351carlo]

Jack B - dewilmoth was correct in his postings. Even though E85 has a higher octane value, just replacing a unit of gasoline with a unit of E85 will result in a leaner mixture, not richer as you posited for higher octane fuels. The analogy copy and pasted for higher octane race fuels is confusing, as I'm not sure how it is relevant. The conversions it uses brings us to the second point however.

Oxygen sensors do not read air fuel ratio. The reason you have to pick the stoich value on your Innovate is because the controller converts the lambda reading to an AFR, post processing. Additionally, stoichiometric ratio of E85 is approximately 9.765, but since the sensor reads lambda, you can simply leave it in the gas stoich range and tune to an indicated AFR of 11.5-12.5 [depending upon your setup and preference] and, as the reading is actually a converted lambda value, that will correlate to the stoich range for the other fuel.

To the OP - I run E85 and it is fantastic. However you should not need to run an additive, whether it be a higher octane fuel or otherwise, on a simple build like that. I would look to datalog your vehicle and determine what is going wrong. Just adding E85 will lean out your car, and not provide the additional benefits of higher fuel volume during combustion that E85 brings.

[Jack B]

1. My comment was directed at higher octane race gas, if you read the thread the direction moved away from E85.
2. I never addressed E85 directly.
3. Read the article by others that I posted.
4. Prior to researching the topic, I thought the same as you.
5. It is like a speedometer calibrated in mph when you want kph.
6. Again, read the article.


Jack B - dewilmoth was correct in his postings. Even though E85 has a higher octane value, just replacing a unit of gasoline with a unit of E85 will result in a leaner mixture, not richer as you posited for higher octane fuels. The analogy copy and pasted for higher octane race fuels is confusing, as I'm not sure how it is relevant. The conversions it uses brings us to the second point however.

Oxygen sensors do not read air fuel ratio. The reason you have to pick the stoich value on your Innovate is because the controller converts the lambda reading to an AFR, post processing. Additionally, stoichiometric ratio of E85 is approximately 9.765, but since the sensor reads lambda, you can simply leave it in the gas stoich range and tune to an indicated AFR of 11.5-12.5 [depending upon your setup and preference] and, as the reading is actually a converted lambda value, that will correlate to the stoich range for the other fuel.

To the OP - I run E85 and it is fantastic. However you should not need to run an additive, whether it be a higher octane fuel or otherwise, on a simple build like that. I would look to datalog your vehicle and determine what is going wrong. Just adding E85 will lean out your car, and not provide the additional benefits of higher fuel volume during combustion that E85 brings.

[Snorman]

To break through all of this white noise for the benefit of the OP...

Do not put E85 into your fuel tank thinking you'll increase the effective octane points and solve pre-ignition/detonation.

All of this discussion about increasing octane points by mixing pump and race gas is worthless talk as the discussion is relative to E85.
S.

[imagine]

Decided against testing a couple gallons of E85, per the feedback in this thread.

[imagine]

Also, to provide added context, the level/frequency of the pinging I hear is low compared to what most people would consider bad or linked to some other problem with the motor. Both cars always made consistent power, no codes, didn't burn oil, etc etc. In the end, for as often as I drive the car, I just gotta find another 100 pump closeby.

[Bruce H.]

Not sure any of that means you don't have a problem that could be serious. Do most other Gen V owners in your climate experience the same audible knock/pinging?

I'm sure others more knowledgeable will correct me if I'm wrong, but the knock response system of the car constantly monitors knock and adjusts the tune so knock so knock should and would never be audible. If you hear it then it sounds like a serious problem waiting to b ecome catastrophic under the right conditions.

[uberpube]

http://www.chevronwithtechron.ca/products/documents/69083_MotorGas_Tech_Review.pdf

[imagine]

Not sure any of that means you don't have a problem that could be serious. Do most other Gen V owners in your climate experience the same audible knock/pinging?

I'm sure others more knowledgeable will correct me if I'm wrong, but the knock response system of the car constantly monitors knock and adjusts the tune so knock so knock should and would never be audible. If you hear it then it sounds like a serious problem waiting to b ecome catastrophic under the right conditions.

I've heard feedback from several Viper owners (multi Gen) that have experienced pinging under all sorts of load. Personally, I've an ear for noises - Mustangs, Vettes, 4G63s, etc. Since the cats have been removed, any previous pinging seems to have cleared up. I've operated some of these cars in cooler weather/other areas of the state and that's usually cleared it up as well. I would assume most would not pick up on it, unless it's really bad.

[Bamfordr]

Why risk it for the marginal gain in power? If you are going full standalone/fuel system and have a competent tuner then sure go for it. I run it in my Supra with ProEFI to compensate for varying ethanol % and love it.

[bulitt]

Guessing I will be avoiding E85 in my 2008...

[nwa_viper]

I’ve ran a couple of gallons of E85 in a tank of non-ethanol 91 octane many times. The cars are E10/15 compatible so either buy it mixed or do it yourself. Pump E85 rarely tests that high, usually around 70% where I am.