E-85 with Increased Fuel Pressure?

[habitatguy187]

Alright, this kind of jimmy-rigg thinking may upset a lot ppl, but oh well, let's see what we can do.

dsmonster had a post about increasing fuel pressure to make your 450s run more fuel, and that got me thinking

It appears that I have an auto fpr on my 1g, which has a higher fuel pressure than the manual fpr's, so I'm getting more fuel, and the ecu is pulling more fuel, therefore my o2 fuel trims usually linger around 70%.

Now my idea is this, what if I start slowly adding e-85 in with my 93 oct? Play around with it until I get very close to 100% on my fuel trims. Would I max out my injectors too quickly with a high e-85 mix and 550s pushing a 14b? It seems ok in my head, I just don't want to run out of injector, I know that jrohner has ran e-85 at boost levels which ppl said couldn't be done with his injectors. Whaddaya guy's think?

And please don't give me any, "don't risk it, just buy dsmlink and do it right" I want to see if this is possible, because in theory it makes perfect sense to me, and I'm going to try it unless someone comes up with some good reasons not to.

 

[Burnett03]

No. No. No. I hate the idea of mixing e-85 and gasoline. It's to incosistent and you never know what mixture you are getting not to mention that sometimes it's e70, sometimes its e85. Not to mention the higher your fuel pressure is the less your fuel pumps puts out. So it's better to get get largers injectors and keep the base pressure at normal levels when dealing with e-85.

 

[rEclipserGST]

Why dont you just try it and log it? It may be cutting corners, but then again were strapped for green. And DSMs are all about old and newly thought up mods. I say run it and let us know what happens. Worst that could happen would be fuel cut correct?

 

[habitatguy187]

Worst that could happen would be fuel cut correct?

Well, it would be real fuel cut, not ecu induced fuel cut. Or I could run too lean and blow stuff up, but I'll be logging so I should be able to watch for it. I'll play around with it a little this afternoon I think.

 

[rEclipserGST]

People never find new things out without breaking things and taking risk here and there. So i support it and even I have mixed e85 and 91 octane... the boost LOVES IT

So I would suggest def. log it and watch to see how CLOSE you can actually get to 100% that way you dont hurt anything. But dont mix more than 40% e85 in there just to be safe. I usually do 3 to 1, 91 to e85. OR sometimes 2 to 1 gal. Just be safe and patient man, let us know the outcome. Plenty of ppl are running straight e85 on stock internals and such with just SS lines.

DO IT!

 

[JayRolla]

Ok you may get away with it, but if you dont have a wbo2 the logger wont show you shit. You can see knock and be happy with no knock, but tuning e85 for over a year now, I found I can run dangerously lean and still have no knock.

A guy tuned with just a logger watching knock and then got a wbo2 hooked up, he was close too 14.0:1 afr's and still had no knock. He was running dangerously lean and didnt even know it.

Also whats the real point. It wont make anymore power since you wont beable too turn up the boost. As soon as you turn up the boost your injectors are going to run out very fast.

 

[thewombis]

We all want to see if its possible to! Give it a shot and post up the aftermath pictures if the holes in your block. I'm gonna do what you said not to, and suggest you just get a log (DSMLink should do the trick PERFECT) and do it the right way. If you can afford to do shotty experiments on a motor, you can afford to buy a $500 logging/tuning setup.

 

[viperlp01]

We has 93 oct hopefully .. My car has never seen less than 93 since i have owned it..

 

[rEclipserGST]

We has 93 oct hopefully .. My car has never seen less than 93 since i have owned it..

In Ohio, we have 87, 89, 91, and 93. BUT Im not paying an additional 5 cents per gallon for 2 points of octane. Thats just dumb. Especially when gas is thru the roof as it is. Theres octane booster in a bottle dude.

 

[JWoodley]

In Ohio, we have 87, 89, 91, and 93. BUT Im not paying an additional 5 cents per gallon for 2 points of octane. Thats just dumb. Especially when gas is thru the roof as it is. Theres octane booster in a bottle dude.

Yea, I'd much rather pay $2-3 for some octane booster than the extra $1 per tank to run premium. I mean 91.5 octane is almost as good as 93, right?

 

[habitatguy187]

Ok you may get away with it, but if you dont have a wbo2 the logger wont show you shit. You can see knock and be happy with no knock, but tuning e85 for over a year now, I found I can run dangerously lean and still have no knock.

I know that the logging by the o2's doesn't show much, but I'm wondering that if I get my fuel trims to around 90%, then the ecu will still be pulling a little fuel (cause I'd be running rich), that way I'd be on the safe side when in boost right?

Also whats the real point. It wont make anymore power since you wont beable too turn up the boost. As soon as you turn up the boost your injectors are going to run out very fast.

Yeah I'm wondering if 550s can support a 14b at 18-19psi with the e-85 mix, I would think so as long as the mix isn't too extreme, but then again I don't know all the calculations for injector sizing and airflow.

In Ohio, we have 87, 89, 91, and 93. BUT Im not paying an additional 5 cents per gallon for 2 points of octane. Thats just dumb. Especially when gas is thru the roof as it is. Theres octane booster in a bottle dude.

Actually I read somewhere that 1 octane point can withstand another 20* Fahrenheit before it detonates, and 5 cents per gallon times 10 gallons is only 50 cents, not bad for an additional 40* fahrenheit overhead.

 

[twdorris]

I know that the logging by the o2's doesn't show much, but I'm wondering that if I get my fuel trims to around 90%, then the ecu will still be pulling a little fuel (cause I'd be running rich), that way I'd be on the safe side when in boost right?

Probably, yeah. But it really depends on why you were running rich to begin with. If airflow metering is off such that it was giving an inflated value at idle and cruise but reading reasonably at WOT, then you'll run a little rich at idle and cruise but not under boost. It can happen, but probably isn't likely enough to worry about much here.

As for the math, it's pretty straight forward. If you're running 43.5psi on an ECU that expects you're running 37, then you're getting an 8.4% increase in flow from that.

sqrt ( 43.5 / 37 ) = 1.084

That makes the 550s act more like 600s. Now, the problem is that 600s on pure e85 is more like 400cc injectors on gasoline. You can get more info on that conversion here:

E85 fuel adjustments

So, as you said, you're going to want to mix in e85 pretty slowly to find that happy middle ground. You should be fine for some playing around, but I can't imagine getting much boost out of it without some larger injectors or running leaner than "normal".

Best answer...give it a shot! You seem to have the basic idea down, so why not play around with it and see how far you get?

Thomas Dorris
ECMTuning, Inc.

 

[habitatguy187]

Well guys I messed around with it a little today and I couldn't seem to get it right. It's almost like T. Dorris said above, at idle and cruise it would be pulling fuel, but any accelerating at all and it was adding fuel, up to 30%. So I added a little more gasoline, and now under partial throttle it bounces around 100%, but at idle it's pulling 25%+.

Also thanks for the calculation and the link, I calculated that if I put in 3 gallons per tank (16 gallons) then my injectors will be flowing 559cc's. I'm going to give that a shot once I drain this tank, there will actually be a little more 3 gallons in there since there's ethanol in it now, so I'll probably just add 2 gallons to this first tank, then go 3 with the next tank.

I'll keep everyone updated and it shouldn't be long since I drive my car a lot.

Also Thomas sorry if I sounded like I'm against link, I'm not at all, I'd like to get link one day but honestly it's probably not ever going to happen, so I'll try to make do.

 

[rEclipserGST]

Yea, I'd much rather pay $2-3 for some octane booster than the extra $1 per tank to run premium. I mean 91.5 octane is almost as good as 93, right?

I put it what it asks which is 91. No need for anything additional especially if you dont race your car everyday. Not to mention I do alot of city driving and i drive for a living. Also the car gets horrible gas mileage. And most places with good gas wax for 7-10 more now. So when I DO want to race or clean the gas, I use lucas. DDD over here.

 

[twdorris]

Also Thomas sorry if I sounded like I'm against link, I'm not at all, I'd like to get link one day but honestly it's probably not ever going to happen, so I'll try to make do.

Not a problem. It's not everyone's cup of tea and I see no problem trying new things either! There are lots of different ways to achieve the same goal.

Thomas Dorris
ECMTuning, Inc.

 

[viperlp01]

Sorry to bring this back from the dead but i was thinking about this.. Our fuel injectors are tested at a specific fuel pressure so you would have to raise the fuel pressure past the constant that they test them at to get anymore fuel out of the injectors.. I see why this guy had problems try to mix it.. He was trying to use calculations that would not work for this situation.. I was debating on doing this to but i think i would have to get a bigger fuel pump and defidently have to get an AFR.. I think what needed to be done is going with a constant mix of fuel and messing with the fuel pressure to get the mix right..

 

[rstchris]

I have almost the same mods as you only with rre660s, 2.5" o2, turboback, cams. I run full e85 and i'm close to maxing my injectors with 12.0-12.2ish about 22psi. The advantage is that I run 22*deg wot at 4500rpm and goes up to 27* by 7800rpm. 0 knock. That is compared to a max of 17* @22psi on 91 with 2 counts of knock. There is lots of power to be made without adding boost. In short, if you run less than 25psi you should be ok with full e85.

 

[bastarddsm]

I ran 450's on e85 with a stock ecu. the trick is to run a 255hp and 58+psi fp. I went trapped 105mph weighing 3300 at 19psi. So it works pretty good.

 

[habitatguy187]

I ran 450's on e85 with a stock ecu. the trick is to run a 255hp and 58+psi fp. I went trapped 105mph weighing 3300 at 19psi. So it works pretty good.

That sounds pretty dangerous . I picked up a set of 750s and I'm going to drop them straight in with a 255hp pump (no afr) and run full e85 and see what happens. Mathematically everything works out decent, but I guess we'll see.