I'm currently experimenting with a 50-50 mix of 87 octane and E-85 (which works out to an actual ratio of about 40%--or less--ethanol. E-85 around here is only guaranteed to be 70% ethanol). I know, watch out for damage to o-rings, fuel pump, etc., but so far (over 2 months) no problems. I've also got an alcohol injection system. With an .036 jet on the alcohol injection system and the Hobbes switch set to bring it on at 8psi, and the E-85/87 octane gas mix, I am running about 25-26psi of boost with NO knock. I don't think I'm getting the same energy as I would out of straight high octane, but it feels pretty strong and it's readily available. Sooo anyway, I cranked the boost up even further--30psi! Still no knock, but power dropped way off. Not like I'd popped a hose or anything. Boost held steady. Just not as much ooomph. Question is: Why would that happen? Seems odd. Might have something to do with reduced air flow as the turbo (TE-44 with 14" K&N, 3" LT1 MAF, Translator, a Powerstroke diesel frount-mount intercooler and a 3" THDP) gets too far out of its efficiency range(??) Or maybe fuel (Walbro 340 set at 42psi for the TT chip)? I didn't have Turbolink hooked up... Any thoughts? BTW, I already turned the boost back down.
Boost vs. power problem
- Thread starter kjhansen
- Start date
BlackBandit
God loves Buicks!
- Joined
- Mar 29, 2003
Could be preignition or your turbo out of it's efficiancy. Do you have a chip that compensates for the fuel? I think alcohol has about half the energy as gas.
Well, since I'm not getting any knock (Casper's knock guage) it's not pre-ignition. E-85 is about a 30% drop in efficiency as opposed to the 50% you suggest. Increased boost, however, should increase efficiency... i.e., get more out of each gallon. According to Mr. Banks (Banks diesel stuff, including turbos) increased compression will make E-85 more efficient--increase fuel mileage and power (he was on "Jay Leno's Garage"). So I'm thinking that increased cylinder pressure (boost) should do the same. But maybe I don't have enough fuel pump (Walbro 340) and injector (009's) to get enough fuel into the system with that much boost. I'm running the 87 octane because I think that technically there's more energy in a gallon of 87 than in a gallon of 93. Anyway, it's burning lots of alcohol what with the E-85 AND alky injection. I'll have to hook up Turbolink and see what's cookin'. Interesting, eh?
Keith
(I think I'm figuring out the answer to my own question)
Keith
(I think I'm figuring out the answer to my own question)
BlackBandit
God loves Buicks!
- Joined
- Mar 29, 2003
First, and this is important, pre-ignition and knock (detonation) are two totally different things. I don't think the knock sensor picks up pre-ignition. As far as the "efficiency" goes I think I said alcohol is has about half the energy, not e-85. Either way though the principle is the same. If you're running a chip designed for gas and you're running e85 you might not have enough fuel in there. Just turning up the boost doesn't change the ratio of air to fuel. Maybe you should turn up the fuel pressure or add fuel in the chip to see if that helps. As for the 87 octane might have more energy thing goes I'm not sure if that's accurate. I know higher octane fuels are more resistant to detonation, but I think that allot of race gas actually releases more energy than the lower octane counterparts. Allot of people assume (wrongly) that because higher octane fuel is more resistant to detonation (which, as I'm sure you know, occurs when too much energy is imparted into the charge) that it must have less inherent energy. That's just not true. FWIW I'm not trying to be abrasive, I'm just trying to give you some food for thought. Hope your project works out. james
I don't think you're being abrasive, so don't worry about it. It's a discussion.
Points taken. I missed the alcohol/E-85 differentiation, sorry. You're right, alcohol won't make as much power as E-85 since E-85 is anywhere from 15% to 30% gasoline--at least around here.
Main point is that the engine probably needs more fuel. I'm pumping more air and not more fuel. I don't have a programmable chip, so will just turning up the fuel pressure do anything if the fuel pump has, like the turbo, reached its max efficiency limit? My understanding is that increasing pressure doesn't necessarily increase fuel flow, just like increasing boost doesn't necessarily increase air flow--just pressurizes it more.
Keith
Points taken. I missed the alcohol/E-85 differentiation, sorry. You're right, alcohol won't make as much power as E-85 since E-85 is anywhere from 15% to 30% gasoline--at least around here.
Main point is that the engine probably needs more fuel. I'm pumping more air and not more fuel. I don't have a programmable chip, so will just turning up the fuel pressure do anything if the fuel pump has, like the turbo, reached its max efficiency limit? My understanding is that increasing pressure doesn't necessarily increase fuel flow, just like increasing boost doesn't necessarily increase air flow--just pressurizes it more.
Keith
- Joined
- May 28, 2001
Plug readings????
Maybe a comparo to the plugs shown here, will give some insites as to where things are headed??
sparkplugreading
Maybe a comparo to the plugs shown here, will give some insites as to where things are headed??
sparkplugreading
Hi, Im not a turbo guy, but if you increased the boost buy 4-5 psi but did not change the fuel pressure you only have about 12 psi at the nozzle now
where before you had 18- 20 psi. you must subtract the boost away from the fuel pressure because the boost is pushing back 30 psi into the injector.
So my take is that you have to low a fuel pressure and the extra boost was requiring more fuel to boot. More fuel required!!! Im otta here Mike
where before you had 18- 20 psi. you must subtract the boost away from the fuel pressure because the boost is pushing back 30 psi into the injector.
So my take is that you have to low a fuel pressure and the extra boost was requiring more fuel to boot. More fuel required!!! Im otta here Mike
Hi, Im not a turbo guy, but if you increased the boost buy 4-5 psi but did not change the fuel pressure you only have about 12 psi at the nozzle now
where before you had 18- 20 psi. you must subtract the boost away from the fuel pressure because the boost is pushing back 30 psi into the injector.
So my take is that you have to low a fuel pressure and the extra boost was requiring more fuel to boot. More fuel required!!! Im otta here Mike
If you are talking about the alky injection pressure, I don't know how that is referenced. The fuel rail regulator is boost referenced, though, so the pressure across the fuel injectors stays constant as the boost changes.
My vote is that you probably went somewhat lean plus put the turbo out of it's best efficiency region so you got less mass air flow than you expected. Why would you make a tuning change like that without a scan tool of some kind hooked up to see what the results were (don't worry, it's a rhetorical question
)?Laziness. Just haven't gotten around to it. And alky injection pressure is easy because it's a pressurized system (air pressure) of my own invention. It works and I don't have to worry about alcohol-compatible pumps. I've had it on for about 9 years now with no functionality problems.
Keith
Keith
Hmmm, here's a thought. 30# through a TE44 and 009's IMHO wouldn't work well at all on straight race gas. Tell you why I think that; When I was heavy into racing mine, I was/am running a PTE44 with (at that time) red stripe 40#'rs. Once I got the boost up near 28# and was starting to flirt with 11.9's the injectors were being driven at over 120% duty cycle to keep up.
I then moved up to MSD 50's and resolved that issue. They run at just over 85% DC at "full song".
Now with that tidbit out of the way, don't you have to go into the chip and modify the injector constant by close to 30% to run E85 (because of it's nature)? That's the understanding I have, and that's assuming pure E85.
You're running a mixture of E85, low octane gas, and alky!!!!
How in the world can you tune with such a witches brew?? You've got to be pulling your hair out trying to figure out where to set the injector constant!!
I then moved up to MSD 50's and resolved that issue. They run at just over 85% DC at "full song".
Now with that tidbit out of the way, don't you have to go into the chip and modify the injector constant by close to 30% to run E85 (because of it's nature)? That's the understanding I have, and that's assuming pure E85.
You're running a mixture of E85, low octane gas, and alky!!!!
How in the world can you tune with such a witches brew?? You've got to be pulling your hair out trying to figure out where to set the injector constant!!
Hmmm, here's a thought. 30# through a TE44 and 009's IMHO wouldn't work well at all on straight race gas. Tell you why I think that; When I was heavy into racing mine, I was/am running a PTE44 with (at that time) red stripe 40#'rs. Once I got the boost up near 28# and was starting to flirt with 11.9's the injectors were being driven at over 120% duty cycle to keep up.
I then moved up to MSD 50's and resolved that issue. They run at just over 85% DC at "full song".
Now with that tidbit out of the way, don't you have to go into the chip and modify the injector constant by close to 30% to run E85 (because of it's nature)? That's the understanding I have, and that's assuming pure E85.
You're running a mixture of E85, low octane gas, and alky!!!!
How in the world can you tune with such a witches brew?? You've got to be pulling your hair out trying to figure out where to set the injector constant!!
Good post. i can barley keep on top of my 91oct and alky let alone adding E85 into the picture.
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