Anyone else running E85 in their vehicle notice an increase in the amount of exhaust your car produces? I was was watching the voluminous vapor roll out from behind my car as I was backing out of my parking spot this morning... interesting, to say the least.
7 comments:
What you are seeing is the increased visible water vapor you get with the colder burn.
What you do not see so much is the very thing you mentioned- increased exhaust volume. A former Chrysler engineer who worked with ethanol up until his retirement tells me that E85 does indeed create much more expansion in combustion and in a properly tuned FFV this is one reason why some of them run at 1/2 the btu energy content difference between E85 and NL(my S10 runs a 12-16% differential vs the 27% energy content diffference). It is not btu's that push the piston down- it is the exhaust gas expansion. I would think that port work and increased exhaust size would be of benefit in ethanol powered vehicles.
This water vapor volume you note is really obvious in the 3.0L Ford FFV's- less so in GM FFV's
Alcohol
Correction- I said exhaust gas expansion- I meant combustion gas expansion.
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Alcohol-
I think you're correct about tweaking engines to maximize power using E85. It just makes me wish I had more time to learn and play with them :)
I am interested in more information from the group here. Alcohol appears to be the tech but the real life information is what I am after. I am a fleet manager looking for information to decide if our fleet will benefit from E85. We have a large percentage of late model Dodge Grand Caravans that are FFV and in the midwest E85 is pretty readily available.
What is the general accepted difference in fuel economy, I am seeing 10% to 30% reduction estimates.
What risk is there in changing back and forth between gas and E85 if there is availability issues?
Is there information specific to the Grand Caravan anywhere? I am not seeing it.
Thanks.
I've been using E85 now for some time now that gas prices have risen again. Here it is 1.799 for E85 as opposed to 2.39 for the premium that my truck requires. That's a 25% price differential and so far I've only noticed about 15-20% reduced gas mileage using straight E85.
The truck is a 2001 Nissan Frontier 4x4 w/ the supercharged engine. I've run straight E85 over several tankfuls with no CEL and average about 14 mpg rather than 17mpg using premium. There's a noticeable decrease in power using E85, but the higher octane is insurance against engine damage.
From what I understand the computer trims the air fuel ratio based on oxygen sensor readings-- Being that this is a supercharged truck, the injectors are already huge to begin with, likely to handle the increased fuel requirements.
One thing that is up in the air is closed-loop operation, where the engine computer uses sensor inputs to pick the AFR off of a "map" instead of oxygen sensor readings. It's essentially a stored program which says X+y+z = AFR. Closed loop operation is used on cold starts (when the O2 sensor hasn't heated up yet) and near and during wide open throttle.
Since the computer will choose a predetermined AFR, I can see the engine running very lean under WOT conditions, thus I try to avoid that at all costs. Combustion temperatures and pressure increase exponentially the leaner the mixture gets.
I haven't had any issues thus far but will sure to report any. The truck has 112k miles, I've used E85 in various concentrations in the past, but never 100% until now.
Nissan Frontier- YOU SHOULD NOT BE DOWN ON POWER- unless you are running lean. I would suggest you stay out of WOT (wide open throttle) which is OPEN LOOP. Open loop is where the O2 sensor is not being used to measure and control A/F mixtures. If you were running proper A/F and timing on a NA engine you should gain 3-5% HP on E85. Super or turbo- much much more HP if boost is added as is possible with 100+ octane.
Fleet Mgr-- the site host seems to have stopped posting- I suggest you join us over at; http://e85vehicles.com/e85/index.php
It is a very active forum for E85- but my short answer to your question is- yes- you can jump fuels back and forth but the rule to remember is- run the engine for at least 5-10 minutes after filling since the Daimler cars were all a "virtual alcohol sensor" instead of a real one- this requires a bit of running after filling to recognize the fuel change and fully adapt to that map for subsequent open loop cold start enrichment.
Come on over to the website above and we can discuss the fuel econ side fully- 10-20% is what i would expect depending on model year and use (long trip hwy vs short trip city).
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RE: Nissan Frontier. Have you ever thought of using a flex fuel conversion kit. With the conversion kit you will get the increase in fuel needed to not run lean and would be able to run WOT with no problems. The kit will also give you more power compared to the sluggish power you have now.
-Jonny Energy
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