So, with my civic now turbocharged and running, I've got some decisions to make regarding the tuning. The basic parameters are 6-10 psi on top of an 11.1:1 compression ratio. The function is an autox car, so good low end and mid range power is more important than top end. That's why I stuck with the relatively high CR and built the system with the goal of near-zero turbo lag. When I started the project, the plan was 100 octane unleaded, which is what it is running on now on a baseline map that is good, but not optimized.
When I started the project though, E85 hadn't hit the lime light. Now that it has, it looks to have some pretty appealing traits for a turbo car, in addition to being cheap (~$3 / gallon vs. ~$8/gallon). It is 105 octane, which should be plenty for what I want. It also seems to have a much better cooling effect on the engine, meaning I may even be able to avoid intercooling all together - which would help spool that much more.
The problem I'm having is that, while it is being used on performance builds, a lot of people seem to be talking out of their ass regarding the execution. On a basic level, it is pretty unanimous that you want ~30% more fuel with E85 than with gasoline to achieve a 9.1:1 stoichometric ratio (vs. 14.7:1 for gasoline), but from there the stories vary. Some folks say that a wideband that was made for gasoline will still read 14.7 when the proper ratio has been achieved. Some people say that no, you want the wideband to read 9.1:1. The vast majority of people sem to up their injector size by ~30% and never even tune it.
So - if I want to run E85 and I want to do it right, what do I need to do? I've got a Walbro 255 pump and 450 cc injectors (vs. 240 cc stock) so I've got plenty of headroom in my fuel capacity. I just need to know how to tune it correctly.
there is a good discussion on e85 on nasioc.com look http://forums.nasioc.com/forums/showthread.php?t=803341
they've been at it for a while...
73 pages on NASIOC. Holy Shnikey...
Thanks for the link. I think. :)
Another question: Can your other fuel system components (tank, pump, lines) take E85?
mel_horn wrote:
Another question: Can your other fuel system components (tank, pump, lines) take E85?
Conventional wisdom is that anything made since the mid 80's should be fine.
All gas has some E in it I think that 15% is the standard for the most part around the country. there's a lot of information on that site, I wish there was as comprehensive a site for my car ( there is a forum though they crashed and lost a ton of information) and if you register, you can change your settings to view more posts per page I see 37 pages lol.
Widebands read oxygen, not fuel. Normally, one set up for gasoline will read 14.7:1 at stoich for any fuel. There are a couple exceptions that you can tell the gauge to use a different point for stoich. The only gauge where I'm sure you can do this with is the Innovate XD-16. Widebands that connect to a laptop can usually display true AFR through the laptop as well.
Matt - Do you guys have much experience with E85? Any local folks using it as a performance fuel?
I dont know much in the way of details.. but heres something
http://corner-carvers.com/forums/showthread.php?t=32040&highlight=boost+corn
MadScientistMatt wrote:
Widebands read oxygen, not fuel. Normally, one set up for gasoline will read 14.7:1 at stoich for any fuel. There are a couple exceptions that you can tell the gauge to use a different point for stoich. The only gauge where I'm sure you can do this with is the Innovate XD-16. Widebands that connect to a laptop can usually display true AFR through the laptop as well.
This is pretty much what I was going to post. The only meters I see that have adjustable a/f settings are the ones we use at work.
And I hate them.
I'd much prefer to read lambda (airfuel/stoich airfuel) or gamma (1/lambda)- which is really the measure of O2 in the exhaust.
Tune to the sensor.
BTW, the gasoline rule of thumb of 12.5:1? You can go richer with e-85- the extra O2 in the alcohol won't slow down the combustion so much, so you can get some more of the cool added benefits.
So, #1- know your sensor, and what it reads/ what it's tuned for. Since it measures O2, it will work across all fuels, but the reading may be only for gasoline.
E-
Thanks guys - that explains it better than anyone else on the web has managed to.
Any opinion on if the cooling properties of E85 as a fuel would negate / lessen the need for an intercooler? Getting rid of the intercooler would eliminate one more source of boost lag. It already spools quite fast, but faster is better.
From what I always understood:
High octane + High compression + Efficient turbo + Short piping run + Moderate boost = No need for intercooler.
DILYSI Dave wrote:
Thanks guys - that explains it better than anyone else on the web has managed to.
Any opinion on if the cooling properties of E85 as a fuel would negate / lessen the need for an intercooler? Getting rid of the intercooler would eliminate one more source of boost lag. It already spools quite fast, but faster is better.
How much boost are we talking about?
Plus, a lot will depend on your ability to tune the injection timing- you'll get more of a cooling effect if you can do some of the injection on an open valve.
E-
alfadriver wrote:
DILYSI Dave wrote:
Thanks guys - that explains it better than anyone else on the web has managed to.
Any opinion on if the cooling properties of E85 as a fuel would negate / lessen the need for an intercooler? Getting rid of the intercooler would eliminate one more source of boost lag. It already spools quite fast, but faster is better.
How much boost are we talking about?
Plus, a lot will depend on your ability to tune the injection timing- you'll get more of a cooling effect if you can do some of the injection on an open valve.
E-
Boost - 8 psi for now, on top of 11.1:1 CR. 4 valve pentroof with domed pistons. I can adjust injector pulsewidth, but not injector timing.
We haven't used it in house but have dealt with a couple customers running it.
I'd still run the intercooler.
DILYSI Dave wrote:
alfadriver wrote:
DILYSI Dave wrote:
Thanks guys - that explains it better than anyone else on the web has managed to.
Any opinion on if the cooling properties of E85 as a fuel would negate / lessen the need for an intercooler? Getting rid of the intercooler would eliminate one more source of boost lag. It already spools quite fast, but faster is better.
How much boost are we talking about?
Plus, a lot will depend on your ability to tune the injection timing- you'll get more of a cooling effect if you can do some of the injection on an open valve.
E-
Boost - 8 psi for now, on top of 11.1:1 CR. 4 valve pentroof with domed pistons. I can adjust injector pulsewidth, but not injector timing.
For that compression ratio, it would be pretty sensitive to any increase in temperature rise over ambient... Hm.
It's kind of a catch 22- 8psi isn't going to raise the temp much, even with a great intercooler. But it will probably be enough to be an issue for 11:1, even with 115 RON.
What system are you using? MS?
What about water injection?
E-
With a gas calibrated O2 tune to 14.7:1 at part load, and 11.5:1 at high load. You'll want to start by throwing about 25% more fuel at it everywhere and then adjusting from there. Timing depends but low load you will want to add as much as 10deg and high load as much as 7deg.. but depends on boost level.
alfadriver wrote:
DILYSI Dave wrote:
alfadriver wrote:
DILYSI Dave wrote:
Thanks guys - that explains it better than anyone else on the web has managed to.
Any opinion on if the cooling properties of E85 as a fuel would negate / lessen the need for an intercooler? Getting rid of the intercooler would eliminate one more source of boost lag. It already spools quite fast, but faster is better.
How much boost are we talking about?
Plus, a lot will depend on your ability to tune the injection timing- you'll get more of a cooling effect if you can do some of the injection on an open valve.
E-
Boost - 8 psi for now, on top of 11.1:1 CR. 4 valve pentroof with domed pistons. I can adjust injector pulsewidth, but not injector timing.
For that compression ratio, it would be pretty sensitive to any increase in temperature rise over ambient... Hm.
It's kind of a catch 22- 8psi isn't going to raise the temp much, even with a great intercooler. But it will probably be enough to be an issue for 11:1, even with 115 RON.
What system are you using? MS?
What about water injection?
E-
Fuel system = zdyne. It's a hacked OE ECU. I had also considered water injection, but didn't know if it would be redundant if the fuel is mostly alcohol in the first place.
well don't forget 8psi at 100 cfm is less ideal than 2psi at 400cfm I could run 21psi all day on my wrx but I was running more efficiently and with more power at 18.5psi. It's all about flow not absolute pressure.
there's a great technical article about it on nasioc, I just cant find it right now. It discusses Flow (CFM) vs Boost (PSI) and the thermodynamic efficiency ranges of different turbos.
DILYSI Dave wrote:
alfadriver wrote:
DILYSI Dave wrote:
alfadriver wrote:
DILYSI Dave wrote:
Thanks guys - that explains it better than anyone else on the web has managed to.
Any opinion on if the cooling properties of E85 as a fuel would negate / lessen the need for an intercooler? Getting rid of the intercooler would eliminate one more source of boost lag. It already spools quite fast, but faster is better.
How much boost are we talking about?
Plus, a lot will depend on your ability to tune the injection timing- you'll get more of a cooling effect if you can do some of the injection on an open valve.
E-
Boost - 8 psi for now, on top of 11.1:1 CR. 4 valve pentroof with domed pistons. I can adjust injector pulsewidth, but not injector timing.
For that compression ratio, it would be pretty sensitive to any increase in temperature rise over ambient... Hm.
It's kind of a catch 22- 8psi isn't going to raise the temp much, even with a great intercooler. But it will probably be enough to be an issue for 11:1, even with 115 RON.
What system are you using? MS?
What about water injection?
E-
Fuel system = zdyne. It's a hacked OE ECU. I had also considered water injection, but didn't know if it would be redundant if the fuel is mostly alcohol in the first place.
Starting to really back up the quotes....
Water injection isn't all that redundant. Well, the part where you get about 20 RON points is, but the cooling side is pretty good. For gasoline, max of about 20% water to fuel. I'd run 10-15% with E85.... As a guess.
What you really need to do is to check the temperature gain. That will really tell you a lot...
E-
alfadriver wrote:
Water injection isn't all that redundant. Well, the part where you get about 20 RON points is, but the cooling side is pretty good. For gasoline, max of about 20% water to fuel. I'd run 10-15% with E85.... As a guess.
What you really need to do is to check the temperature gain. That will really tell you a lot...
E-
I think my base assumption on the "E85 = no intercooler" train of thought was that, if E85 burns at 100 - 200 degrees cooler in the cylinder (which seems to be the interweb's consensus) then making a 50 degree change to intake temp on the front end is comparitively negligible. Is that base assumption valid?
Checking temp gain would help. I don't really want to push the car until it's tuned though, and I don't want to spend the dyno money tuning until it's finalized. Thus, the tail chasing...
But wouldn't the E85 "in cylinder" temp change with proper tune? Once you are getting the correct amount of fuel, spark and proper timing of both the temperatures should be a little closer than the generic 100-200* mark.
DILYSI Dave wrote:
I think my base assumption on the "E85 = no intercooler" train of thought was that, if E85 burns at 100 - 200 degrees cooler in the cylinder (which seems to be the interweb's consensus) then making a 50 degree change to intake temp on the front end is comparitively negligible. Is that base assumption valid?
You can't cool the incoming air too much. It can both increase the density and in theory the efficiency of the motor. It's not just for detonation resistance.
But if I can reach my power goals (I'm thinking anything more than 200 - 250 will be useless) either with or without intercooling, then I think it would be to my advantage to do so in the quickest spooling manner possible. Is that a reasonable thought?
