E85 Conversions (Andy?)
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ive seen a few retros to e85 and this is the first ive heard of the FQS. is e85 really that inconsistant? i know factory FFV's have them so they can switch back and forth between regular and e85 and corect fuel trims for differant amounts of ethanol. but is it really necessary on something that would always run it?
if i was doing this to my civic would i be able to use crome to tune for it? i mean i could just turn the o2 sensor input off through crome that way it wouldnt be trying to correct anythign and it would just go off my maps right?
here a psht, there psht, everywhere a psht psht
PVC SQUAD MEMBER #2- 95 CIVIC EX- DD 320whp on a mustang dyno
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I can't tell you how it is done, but I will tell you HP wise it's not worth it on a stock mustang. Yes you pick up power but it is minimal. I will not divulge any specs because I cannot- due to various contract issues. I can accomodate interested parties, but I still wont divulge too much info. We've done 500+ of these, so I'm not speaking hypothetically.
thanks, andy -
ExplodR;156665 wrote:
Could you get a little more power with E85 even on a basically stock vehicle due to the ability to advance timing more since E85 has a higher octane rating?im pretty sure if you ran e85 you would HAVE to run more timing or F.I. to make the ORIGINAL horsepower. you make less power on e85 thats why it gets worse gas mileage. i think becuase its so much higher octane rating that it burns TOO slow. at least from what i understand, i havent dealt with e85 much.
here a psht, there psht, everywhere a psht psht
PVC SQUAD MEMBER #2- 95 CIVIC EX- DD 320whp on a mustang dyno
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SPANISH-RICE;156663 wrote:
ive seen a few retros to e85 and this is the first ive heard of the FQS. is e85 really that inconsistant? i know factory FFV's have them so they can switch back and forth between regular and e85 and corect fuel trims for differant amounts of ethanol. but is it really necessary on something that would always run it?right, the FQS is because you may have a varying degree of normal gas and E85 in the tank at a given time. If you knew you were running "pure" e85 you wouldn't need it.
Note that in winter, pump E85 usually becomes E70 to make cold starting easier, due to the different temperature/vaporization properties of Ethanol vs gasoline.
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thrash;156674 wrote:
right, the FQS is because you may have a varying degree of normal gas and E85 in the tank at a given time. If you knew you were running "pure" e85 you wouldn't need it.Note that in winter, pump E85 usually becomes E70 to make cold starting easier, due to the different temperature/vaporization properties of Ethanol vs gasoline.
crome double sided eprom! FTW! one tune for summer blend one for winter blend lol!
here a psht, there psht, everywhere a psht psht
PVC SQUAD MEMBER #2- 95 CIVIC EX- DD 320whp on a mustang dyno
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ooo answered two at a time!
here a psht, there psht, everywhere a psht psht
PVC SQUAD MEMBER #2- 95 CIVIC EX- DD 320whp on a mustang dyno
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maybe he just wants to be environmentally friendly?
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ExplodR;156675 wrote:
ive heard of people using a chip that you can switch between different tunes for e85 or regular gashow does that work?
Are you asking how good or bad it is in practice, or what is the mechanism that makes this possible?
I'll try and answer the latter:
The short version is - an ECU tries to answer the question "how much gas does the engine need right now", based on things like air mass, engine load, engine rpm, and so on. Generally finding a closed form formula like
fuel = FigureOutFuel ( rpm, air_mass, load )
is not possible. Instead, the implementation of "FigureOutfuel" is based on lookup tables, commonly called "maps" in the tuning communitiy. Essetially you've got a big table, where RPM is one axis and manifold pressure (in MAP based systems) is the other. The "value" of a "bin" is either directly or indirectly going to tell you the injector duration time. the ECU knows the fuel pressure of the system and the size of the injector, so controlling how long the injector is open is the way it meters the right amount of fuel.
An analagous situation exists for controlling spark advance or retard, although there's much more practical variety in how ECU's control spark (if they do so at all)
So if you have a car that you want to run on two (or more) wildly diffent fuel grades, like Pump Gas vs E85, or Pump Gas vs 110 race gas.. you basically just need to fill out the table of "how much gas for this RPM and MAP?" once per fuel type. The ECU then needs some hook to tell it to switch which table it is reading form.
Note that this is a simplification - there are different algorithms for calculating fuel.. what i've described is called "speed density", and in the application i am most familiar with (megasquirt), the table actually stores the "volumetric efficiency" of the engine at that MAP / RPM combo, from which the injector open time is derived (i.e. unlike what i suggested above, it doesn't actually store the injector open time directly).
Another fueling algorithm is called "Alpha-N" which is based only off of load (throttle position sensor.. i.e. how hard you're hitting the gas) and RPM. This is typically used for NA race engines where you have a prety solid idea of what the flow characteristics are, and you maybe don't care about some other drivability characteristics... and perhaps you don't have reliable MAP signals.
Still another method is the good ole carburettor. LIke fuel injection, it is still answering the question of "how much gas does the engine need right now?", but unlike digital fuel injection, it doesn't have the luxury of programmable data points of engine characteristics. If you were to make an n-dimensional graph of the fueling map of a tuned engine, it wouldn't be smooth.. there would be bumps here and there of optimally tuned points in the map, that, for whatever reason, don't represent a smooth contour along any n-1 dimensional cut of the surface. This is the flexibility that map based EFI gives you.
Carbs don't have this map based "programmability" - the carb is a mechanical device that necessarily has a continuously evaluatable function. If the air (and other inputs) are "this", the output will "always" be that, and that output is a characteristic of the mechanical construction of the device. You can't make it behave one way at 500 rpm and a different way at 515 rpm, and yet another way at 600 rpm.. the carb effectively describes a fuel delivery graph that is a continuous smooth curve through all the rpm points... 500, 515, 600... all the way up to whatever. That function might be linear, or might be polynomial.. but it is still a function.
Since you can't fine tune any point on this function like you can with table-based EFI, you effectively need to pick a region of operation you care about most (i.e., 4000-7000 rpm, 70 F ambient, average humidity), and set the carb up for those conditions. You're basically fitting the curve of the carbs delivery function to the fuel requirement characteristics of your engine under the conditions you're targetting.
Although i can explain the basic principles of engine management, i don't think I could tune an engine. It's still a bit of a black art and you just need experience to do it. Nobody knows "the answer" and the physics of fuel combustion still isn't perfectly understood (if it was, we wouldn't use table based EFI.. we'd have a closed-form equation for fuel delivery instead of a look up table).
If you're interested in this stuff, BOSCH makes a few books about Engine Management that go up through the end of the 80s and early 90s. BOSCH supplied almost all of the fuel injection systems used on any european car from that era... VW, Audi, BMW.. you name it.
You can also read about Megasquirt, which has a fantastic amount of technical info available that is pretty easy to digest. If you wanted, you could read the source code to the ECU - it's all open software.
Note that a few people are running E85 on Megasquirt already. As well as more exotic fuels like Propane
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So is the guy that works at Luther Chevy that told my coworker that E85 Retrofitting a non-e85 vehicle will eat away the exhaust system full of shit or will E85 eat away your exhaust system if it isn't stainless steel?
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PineInchNenis69;156864 wrote:
So is the guy that works at Luther Chevy that told my coworker that E85 Retrofitting a non-e85 vehicle will eat away the exhaust system full of shit or will E85 eat away your exhaust system if it isn't stainless steel?He is full of shit. Have your coworker call and speak with Andy at Dynotune.
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Oh he wasn't planning on doing it I don't think, he was just talking about E85 and the guy was saying that E85 conversions will eat away non stainless exhaust systems due to its higher acidity.
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