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Old 03-20-2008, 06:14 AM   #1401
HamFist
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Threadjack time!

Chalk another up another driveline part kill! I juiced a buddy's turbo Legacy on 20% ethanol and Oxytane. He broke a u-joint last night. We're going to go fix it, put on 50% and see what we can break next . My money's on the clutch or a shift fork.

Bets?
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Old 03-27-2008, 02:31 PM   #1402
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This is an awesome thread both for the knowledge that is being shared and the fact that it debunks a bunch of E85 myths.

I'm planning to convert my N/A 2004 Subaru Outback to E85 by boosting the fuel pressure a bit (and some other mods if necessary) and have a question about open loop operation.

If the ltft is able to compensate for the fuel being used, then wouldn't this info be used to adjust open loop operation so that everything is the way it should be, i.e. not too lean and not too rich? I can imagine things getting too lean if I run out of injector or fuel pump pressure at WOT, but within these physical limits I figured the ecu would make everything OK.

Btw, it really sucks that the subaru techinfo site doesn't have any information on the ECU and its operation.
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Old 03-27-2008, 07:21 PM   #1403
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will pe 650cc injectors be enough for a 2.0l with evoIII 16g on E85 with base fuel pressure bumped from 43.5 to 50psi
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Old 03-27-2008, 07:25 PM   #1404
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depends on how much boost you plan on running. with my evoIII 16g, im going to be using 850cc injectors to run around 22 psi.

idk how much of a difference 1 psi of fuel pressure does, but im going to guess its not enough.

if your running the walbro, you could probably go higher then 50, they say its good for 70+, but i wouldnt go that far.
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Old 03-27-2008, 10:31 PM   #1405
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Quote:
If the ltft is able to compensate for the fuel being used, then wouldn't this info be used to adjust open loop operation so that everything is the way it should be, i.e. not too lean and not too rich?
My experience is that the LTFT's do not fully compensate on the open loop fueling, and the car will go lean at WOT. If you increase fuel flow by 15% or so, the ECU will do an acceptable job of making it a FFV as long as you do not run serious boost. I tried that for a while and it was adequate for a daily driver but WOT was a bit too lean for my taste and I eventually went the full 30% increase in fuel flow because I was running E85 all the time. By using an adjustable fuel pressure regulator I have two methods to control the fueling. I make gross long term changes by rescaling the injectors but I can make quick road side changes by adjusting fuel pressure so if necessary I can run plain gasoline with no problem after spending about 30 seconds under the hood and turning the adjustment screw about 1 full turn or a bit more to reduce fuel flow on straight gasoline.

Read my notes about a home made FFV setup, I have a link to it on the front of this FAQ in post #4.

Larry
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Old 03-28-2008, 12:31 AM   #1406
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i just want to say thank you larry, again!


we have also tried running e85 in my dads 2000 Ford F250 v10, with NO prblems at all! we did a 50/50 mixture! no CDL's, no prblems! we're happy that we can do a 50/50 minture to save us some money filling up this beast of a truck! (we spend about $70 on the 50/50 mix, where as we would be spending near $85 to fill her up)
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Old 03-28-2008, 04:12 PM   #1407
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Quote:
Originally Posted by hotrod View Post
My experience is that the LTFT's do not fully compensate on the open loop fueling, and the car will go lean at WOT.
I guess this is one of those instances where it should be able to fully compensate but it doesn't. I've read and reread most of the posts here and the functioning of the ecu in open loop is one of my lingering curiosities.

Thanks again for all the info.

-Douwe
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Old 03-28-2008, 05:47 PM   #1408
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hotrod you have you come up with a more concrete formula for calculating injector sizing

something like
440cc @ 2.5 bar gas = X at Y bar of e85
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Old 03-28-2008, 07:52 PM   #1409
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hotrod you have you come up with a more concrete formula for calculating injector sizing

It depends a bit on how conservative you want to be but you can get a pretty quick estimate doing it this way.

Fuel flow required is directly proportional to the total air flow, which obviously changes with boost pressure etc.

On gasoline, you need about 1.6 - 1.8 cc/min static flow on each injector for each hp the engine makes (4 injectors total)
You need about 2.0 - 2.3 cc/min static flow on each injector for each hp the engine makes on E85 (4 injectors total)

1 HP approx equals 1.45 CFM = approx 0.108025 lbs air flow

Our engine needs about 0.59 lbs of gasoline per hp / hr. Each gallon equals 3785 cc, and gasoline weighs about 6.2 lbs/ gallon, so that 0.59 lbs of gasoline is 0.095 gallons or 360 cc/min injector flow on 4 injectors. That means you need 90 cc/ hr injector flow per hp or about 1.5 cc/min per injector to make one hp on gasoline.

Since E85 requires about 30% more fuel that works out to about 1.95 cc/min of E85 to make a hp.

Since you can approximate the maximum power you can make based on the airflow in CFM divided by 1.45 that is a handy way to ball park your injector size.

For E85 take your turbochargers max flow in CFM at the boost you expect to run and divide by 1.45, then multiply by 2.0 and you will be pretty close in cc/min for each injector.

For gasoline it would be divided by 1.5 giving 403 cc/min on the stock turbo with gasoline.

Stock turbo flows 390 cfm max flow at 14.7 psi
390/1.45 x 2.0 = 538 cc/min on E85

16G small max flow 505 cfm
505/1.45 x 2.0 = 696 cc/min on E85

20G max flow 695 cfm
695/1.45 x 2.0 = 959 cc/min

If you do not want to muck around with the formula it simplifies to turbo air flow in CFM at the boost pressure you intend to run x 1.38 will give you the approximate cc/min static flow you want to use for your injectors on a 4 cylinder engine.

simplified formula :
assuming 4 cylinder turbo engine

(CFM at target boost) x 1.38 ~= static injector flow cc/min for each injector




Larry
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Old 03-31-2008, 09:18 AM   #1410
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Hotrod, what can you do for easier cold starts on E85
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Old 03-31-2008, 09:41 AM   #1411
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Old Fuel Pressure 43.5psi
New Fuel Pressure * 50psi
Old Flow Rate 740cc

New Flow Rate 796cc
used the fuel pressure calculator to find out that my 740 injectors should be sufficient. on Deatschwerks website http://www.deatschwerks.com/catalog/...alculators.php
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Old 03-31-2008, 12:05 PM   #1412
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thanks for the explanation

vf-22 at 18 psi -490 cfm

something like 675cc

which is slightly lower than what i had though

i am thinking 650ccs at 50 psi for 696cc would give a nice overhead
or 740ccs and skip the FPR

Last edited by Jaxx; 03-31-2008 at 12:10 PM.
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Old 03-31-2008, 06:45 PM   #1413
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Quote:
Hotrod, what can you do for easier cold starts on E85
Low tech add a couple gallons of gasoline to the tank if the weather gets very cold.

Starting technique:
Turn on the ignition and let the fuel pump prime the system to full fuel pressure then fire the engine (about 10 seconds prime time).

Tune wise:
Good plugs with a strong spark ( I run the Pulsestar plugs right now and they helped with cold starting, other plugs or wider plug gaps may also help)

Good strong battery with high CCA rating so the engine cranks fast cold and has good spark energy on cold start.

One local tuner suggests dialing in a bit extra ignition advance at low rpm (below 1000 rpm)

Enrich the mixture under cold start.

Slightly increase the idle rpm to help it run when it is dead cold.

Add some sort of intake air preheat .
There has been some debate on the E85 forums of various ways to slightly pre-heat the intake air on first start. Cold starting improves dramatically at about 45 -50 deg F so even a small increase in intake air temp on cold start would be very helpful.

Larry
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Old 04-03-2008, 01:17 AM   #1414
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So I have not read through this entire thread yet -- and I will before I put E85 in my car, which I'm planning to do for the summer because I just found two places in Rochester that sell it.

I have a few questions about measuring the right AFR.

I've read the ECU will richen the fuel trims somewhat if you put E85 in the tank on a stock tune, is this because the stock o2 sensor reports >1 lambda when it initially injects a 14.7:1 mixture (which otherwise would be reported as 1 on gasoline) -- so the ECU compensates until the stock narrowband reads 1 (which would appear to be 14.7:1 on a gauge but is really ~9.8:1?) Am I on the right track here??? How does the ECU know anything about the nature of ethanol and what a stoich mixture is?!?! Anyway, if the ECU does richen the mixture based on my theory above, my stock sensor would be reporting 14.7:1 but my LC-1 in gasoline mode would read 9.8? Should I tinker with the multiplier mode on my LC-1 software or leave it on gasoline (14.7) and tune for 8:1 on the gasoline scale for max power or would that be off?
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Old 04-03-2008, 02:01 PM   #1415
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It's been stated before, but it's hard to understand at first.

1) Oxygen sensors don't read the fuel, they read the Oxygen.
2) It doesn't matter what fuel you use, stoich will always be lambda 1.0.
3) The sensor and the ECU both work in lambda.
4) The guage is used to convert lambda to AFR.
5) The ECU doesn't have to translate AFR's for different fuels because it works in lambda.

That being the case, you can pretend that it's gasoline in the tank and tune the E85 using gas AFR's, you can tune the E85 in lambda, or you can have your wideband read E85 AFR's and change the definition files in your tuning software to read E85 AFR's.
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Old 04-03-2008, 07:31 PM   #1416
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Thanks man that snapped some fingers in front of my face...
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Old 04-04-2008, 08:56 AM   #1417
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np.

Regarding E85 usage, I'm on my second tank. I've wanted to run it for a while, but all the stations were too far away to make it practical. Now there's one at the Meijer near my house.

I've got my original 148k mile 2.0 and TD04 hooked to a 6MT and use modded stock injectors and a 190lph Walbro that I bought back in 1993. I adjusted my injector scaler to 585 (from 835) and added 3 degrees to my timing advance tables. A small tweak to the RPM values in my Wastegate Duty table to get rid of a spike with my GM BCS and that's all I've really done so far. My road dyno spreadsheet says I picked up 25-30 hp. My last 1/4 mile run was a 13.17, so I should be solidly in the 12's now. It should be illegal for a TD04 to be this fast...
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Old 04-04-2008, 03:28 PM   #1418
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I think it's cool you're running a 148k mile engine that hard. What oil do you use? I've come across some other maintenance issues to tell you guys about.

I just bought some 565's a little bit ago. The guy I bought them from said that E85 corroded his factory WRX fuel regulator after swapping in larger injectors. I asked if he tried to crush the regulator to raise the pressure and he said no. I haven't had a problem with any of the three I have and never heard of another case of it, even with you guys. His new injectors are fine. It happened quick on his car, too. Any ideas? He didn't want to make a stink, but was sure to ask me. I've never had to pop one open since it's a non serviceable unit and mine never leaked.

I'll be going over my rubber fuel lines anyway just to pick them apart. On gas and ethanol both, they have a dry, hard, and waxy texture on the outside when cold. They seem to scratch and nick more easily in cold weather. It sounds silly, but these factory lines are like gouging a candle or soap when they're cold if you hit them with the edge of something. Has anyone else noticed? I goofed and nicked the passenger side line up front, so it's no big deal to replace, but that little keyster of a hole could make big problems, and all the rubber line does the same hard waxy behavior when near freezing or below. How easy it was to damage is what concerns me.

Last edited by HamFist; 04-04-2008 at 03:36 PM.
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Old 04-04-2008, 03:32 PM   #1419
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Are you sure the part of the line getting nicks in it isn't just a sheath around the outside of the actual line? if it's that easy to scratch, I would think fuel pressure would just blow right through.

All of the fuel system components should handle e85 just fine in most of the cars on this board unless some of you guys are driving cars from the early 80's or before.
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Old 04-05-2008, 05:09 PM   #1420
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TP--you're right about the nicks+ scratches on the outside of the line. They aren't deep, but I still don't trust it. I didn't expect that fuel line to be as easily damaged, though. It's like they're easier to damage in cold weather, but I could be wrong.
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Old 04-09-2008, 12:56 PM   #1421
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So if i wanted to put E85 into my car, on the stock turbo and injectors, and with a walbro 255, with a stage 2 tune...... What mixture would be best to run? sorry, im just having a hard time comprehending all these terms. lol. i just want to know the best mixture that wont hurt the car. can anybody tell me?
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Old 04-09-2008, 01:46 PM   #1422
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Quote:
Originally Posted by 02REX4LIFE View Post
So if i wanted to put E85 into my car, on the stock turbo and injectors, and with a walbro 255, with a stage 2 tune...... What mixture would be best to run? sorry, im just having a hard time comprehending all these terms. lol. i just want to know the best mixture that wont hurt the car. can anybody tell me?
You'll have to figure that out yourself. Start with a very small amount of E85 and then raise the mix a little at a time. Datalog to make sure the injectors and Fuel Learning are OK and stop when you reach the limit. Stage 2 on my car maxed out my stock injectors...
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Old 04-09-2008, 02:05 PM   #1423
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Quote:
Originally Posted by 02REX4LIFE View Post
So if i wanted to put E85 into my car, on the stock turbo and injectors, and with a walbro 255, with a stage 2 tune...... What mixture would be best to run? sorry, im just having a hard time comprehending all these terms. lol. i just want to know the best mixture that wont hurt the car. can anybody tell me?
If you are talking about mixing E85 w/pump gas.... 20-25% E85/75-80% 93oct worked nicely for me. If you are talking as much E85 as you can then yeah, what that guy said ^^^
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Old 04-09-2008, 04:11 PM   #1424
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yeah im talking about mixing pump gas. but all i have here in AZ is 91.
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Old 04-12-2008, 04:58 PM   #1425
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Quote:
Originally Posted by bluescoobywagon View Post
My road dyno spreadsheet says I picked up 25-30 hp.
The guy that tuned mine is getting about 20-30 hp on the Dyno on stage 2 tunes.
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