Cal Club Autocross Forums

Bill Martin wrote:

Marshall Grice wrote: higher energy chemical mixture than gas

In what way? Gasoline is significantly higher than alcohol in BTUs/lb.

HA, i was waiting for someone to bite on that one.

gas has more btu/lb but you also have a significantly richer stoich mixture with ethanol. the result is with ethanol you release more btu per combustion cycle than gas.

I got a large 20 lit container and I'm going to get some E85 today probably from the Westwood station... I assume the quality of E85 in the 3-4 stations that we have in LA should be well controlled right?

Along with the E85 will go my new 1000cc/min injectors (need to pick them up tonight too).
If everything goes as planned I should be able to install the new injectors/harness, modify the fuel maps, have the car running sometime next week and dyno tuned next Saturday.

Marshall Grice wrote:

Bill Martin wrote:

Marshall Grice wrote: higher energy chemical mixture than gas

In what way? Gasoline is significantly higher than alcohol in BTUs/lb.

HA, i was waiting for someone to bite on that one.

gas has more btu/lb but you also have a significantly richer stoich mixture with ethanol. the result is with ethanol you release more btu per combustion cycle than gas.

Correct. But we're talking quantity, not quality. I would say E85 is a lower energy mixture, but you get to use more of it. I can get drunker on beer than gin because I can drink a lot more of it. Doesn't mean beer is higher proof. (Now that's just a hypothetical example.)

And to throw another stone. Evaporative cooling used to be a factor with alcohol/carb cars because the incoming air was chilled in the intake manifold, increasing its density. But FI engines inject the fuel way too late in the intake tract to have the same effect, don't they? Just a question, not a fact.

PS, a link of interest on toluene etc: http://sportscarforums.com/f13/toluene- ... -3257.html" onclick="window.open(this.href);return false;

I guess to answer Mako's original question, Yes, the MSDS for Toluene says it's corrosive to Rubber, Similar to Ethonol.

Bill Martin wrote:
Correct. But we're talking quantity, not quality. I would say E85 is a lower energy mixture, but you get to use more of it. I can get drunker on beer than gin because I can drink a lot more of it. Doesn't mean beer is higher proof. (Now that's just a hypothetical example.)

Why do i feel like we just walked into the Torque vs Horsepower argument.

Mako Koiwai wrote:I'll see if I can find that TURBO magazine article ... it was not web regurge

Hey Mako, i'm not disputing that F1 ran heptane and Toluene or that Toluene is a part of pump gas. Just that 91 is just 87 with more toluene, if that was the case 91 would be significantly less lubricating than 87 and lead to higher engine wear. I'm thinking the whole formula changes slightly if they are upping the percentage of Toluene.

Probably ... the article specifically said that they were surprised that 100 octane 76 pump gas was just 91 with added Toluene. This magazine article in SportsCompact, not Turbo:
http://www.modified.com/features/sccp_0 ... to_04.html

... looking into getting a copy of the article.

Bill Martin wrote: Correct. But we're talking quantity, not quality. I would say E85 is a lower energy mixture, but you get to use more of it. I can get drunker on beer than gin because I can drink a lot more of it. Doesn't mean beer is higher proof. (Now that's just a hypothetical example.)

I see what you're saying. but the mixture i'm refering to is the fuel/air mixture, not the mixture of components in each fuel. So E85 has less energy content, but a higher energy mixture than gas. to follow your analogy, if you only get one 4 ounce drink, you get more effect from the one with the highest proof, it doesn't matter that one drink has 1 shot of everclear (gasoline) and the other drink has 3 shots of vodka(E85). (...ratio's not correct) and we're dealing with roughly the same mass of air so it's not like you can say that you get 6 beers or 1 shot of gin...

Bill Martin wrote: And to throw another stone. Evaporative cooling used to be a factor with alcohol/carb cars because the incoming air was chilled in the intake manifold, increasing its density. But FI engines inject the fuel way too late in the intake tract to have the same effect, don't they? Just a question, not a fact.

agreed. infact on a N/A car you actually get a "negative supercharging" effect because the fuel evaporates and cools after the intake valve has closed, thus reducing the cylinder pressure. It's not all bad though because reduced pressure on the compression stroke help reduce the 'negative work' in the cycle and the lower temp reduces the knock threshold. you can adjust your timing to get back some of the peak pressure. you could move the fuel injectors further away from the intake valve and gain back a lot of the cooling effect and get more density increase.

On a force inducted car you just increase the boost and call it good.

Bill Martin wrote:And to throw another stone. Evaporative cooling used to be a factor with alcohol/carb cars because the incoming air was chilled in the intake manifold, increasing its density. But FI engines inject the fuel way too late in the intake tract to have the same effect, don't they? Just a question, not a fact.

I'd think that the finely-misted fuel spray with it's very high surface area will allow the alcohol to absorb heat pretty well in that short time. Probably just as good as (relatively) dribbled fuel coming out of a carburetor and travelling down a long intake tract.

Both systems include fuel with the air in the most turbulent section of intake (port and valve) so there is strong mixing as well as the time and effects of the compression stroke so neither has an advantage there.

Thinking further, you could say that the carb setup will also cool the intake runners which means that it's taking heat out of the intake material and not the air that you want to go in the cylinder.

Marshall Grice wrote: agreed. infact on a N/A car you actually get a "negative supercharging" effect because the fuel evaporates and cools after the intake valve has closed, thus reducing the cylinder pressure. It's not all bad though because reduced pressure on the compression stroke help reduce the 'negative work' in the cycle and the lower temp reduces the knock threshold. you can adjust your timing to get back some of the peak pressure. you could move the fuel injectors further away from the intake valve and gain back a lot of the cooling effect and get more density increase.

On a force inducted car you just increase the boost and call it good.

A long-time engine builder I used to work with (drag racing, but he also did sprint cars) once told me that, for the same engine combination, peak engine power will be close to the same with both fuels, but gasoline will always make more torque. You have to make a lot of changes (increasing compression being #1) for the fuel change to have any merit. If you don't have boost or a C/R that requires race gas (meaning 12:1 or more) there's no benefit to alcohol as a fuel.

Steve Lepper wrote: for the same engine combination, peak engine power will be close to the same with both fuels, but gasoline will always make more torque.

got any comments Bill?

Marshall Grice wrote:

Steve Lepper wrote: for the same engine combination, peak engine power will be close to the same with both fuels, but gasoline will always make more torque.

got any comments Bill?

I've got multiple dyno graphs, both for VP MS 109 & E85 vs. 91 octane that say otherwise!

Mako Koiwai wrote:76 100 octane pump fuel is simply 91 octane with added 114 octane Toluene ... according to a Turbo magazine octane booster test from a number of years ago. They had a chemical analysis done. I believe they said the 91 octane gasoline was basically 87 with added Toluene. So it would seem we're always exposing our cars innards to Toluene. I was just adding a bit more to 91 to occasionally make around 94.

Anyone have more data on this ...


(The early F1 Turbo cars ran on Toluene with a neutral "filler" to create their desired octane level.)

I'm not a chemical engineer so I'm not an expert on this but I do know that the 91 octane gas we (ExxonMobil Torrance) produce is not just 87 with higher octane additives. They're really blended from all of the same blendstocks, but just in different proportions. So 91 will have more reformate, alkylate, and butane, but less FCC naptha for example. I'm not that familiar with what they use for 100+ octane blends.

Maybe compare MS109 with E85. I think that would be more apples to apples comparison.

Marshall Grice wrote: agreed. infact on a N/A car you actually get a "negative supercharging" effect because the fuel evaporates and cools after the intake valve has closed, thus reducing the cylinder pressure. It's not all bad though because reduced pressure on the compression stroke help reduce the 'negative work' in the cycle and the lower temp reduces the knock threshold. you can adjust your timing to get back some of the peak pressure. you could move the fuel injectors further away from the intake valve and gain back a lot of the cooling effect and get more density increase.

On a force inducted car you just increase the boost and call it good.

That was you saying you're not an engine guy, right? ;)

Kurt Rahn wrote: That was you saying you're not an engine guy, right? ;)

yeah, something like that.

what can I say, i had to do a little research for the evo.

Marshall Grice wrote:

Kurt Rahn wrote: That was you saying you're not an engine guy, right? ;)

yeah, something like that.

what can I say, i had to do a little research for the evo.

You're kinda scary.

John Coffey wrote:Maybe compare MS109 with E85. I think that would be more apples to apples comparison.

I was also responding to this from Steve:

"You have to make a lot of changes (increasing compression being #1) for the fuel change to have any merit. If you don't have boost or a C/R that requires race gas (meaning 12:1 or more) there's no benefit to alcohol as a fuel."

I, obviously (SP rules), don't have a bump in CR or boost (tell me again, Marshall, why CSP should have a higher PAX than BSP?), and I got about a 5% increase over 91. And in answer to you, John, that's about the same as what I got out of the MS 109. I actually think there is a little more to be gotten from E85, and when I get enough $$, I hope to take the car back to Sean Church @ Church Automotive to see what magic he can weave - maybe he can get +400hp for me too!

Bill Schenker wrote:

John Coffey wrote:Maybe compare MS109 with E85. I think that would be more apples to apples comparison.

I was also responding to this from Steve:

"You have to make a lot of changes (increasing compression being #1) for the fuel change to have any merit. If you don't have boost or a C/R that requires race gas (meaning 12:1 or more) there's no benefit to alcohol as a fuel."

I, obviously (SP rules), don't have a bump in CR or boost (tell me again, Marshall, why CSP should have a higher PAX than BSP?), and I got about a 5% increase over 91. And in answer to you, John, that's about the same as what I got out of the MS 109. I actually think there is a little more to be gotten from E85, and when I get enough $$, I hope to take the car back to Sean Church @ Church Automotive to see what magic he can weave - maybe he can get +400hp for me too!

Plus E85 is only 3 bucks a gallon, MS109.. a little more.

Bill Schenker wrote:(tell me again, Marshall, why CSP should have a higher PAX than BSP?)

well since you seem to forget, it's because CSP is faster than BSP.

...something about 1000lbs less weight and the same width tires. why does it matter how much power you make when the only time you have to hit your brakes is after the finish lights?

Aaron Goldsmith wrote:
Plus E85 is only 3 bucks a gallon, MS109.. a little more.

Amen to that!

Mako Koiwai wrote:I was trying out Toluene as an octane booster years ago. When I replaced the fuel pump, the heavy duty rubber fuel line that attached to the pump cut like butter, when I pulled it off with a pair of pliers! So a synthetic rubber line would have held up better?

Not necessarily as it was a matter of time. The reason why natural rubber will dissolve quicker in toluene is due to the limitations of the polymerization process of natural latex. Synthetic rubber can be made to be more selective to a "stronger" type of polymerization but it's still rubber. in general, toluene is very corrosive to any type of rubber.

Rubber will hold up better against ethanol but it will still deteriorate within a few years. I believe they make ethanol-resistant rubber, which only means it will take x years longer for the rubber to start breaking apart in ethanol. I don't know if they have an automotive application for it though.

Bill Schenker wrote:

Marshall Grice wrote:

Steve Lepper wrote: for the same engine combination, peak engine power will be close to the same with both fuels, but gasoline will always make more torque.

got any comments Bill?

I've got multiple dyno graphs, both for VP MS 109 & E85 vs. 91 octane that say otherwise!

Says the guy who can't keep valves in his engine... ;)

There's your problem: 109 is too much octane (slow flame travel) and 91 is not enough. Also, I would also stay away from oxygenated race fuel (hint: I can show you valve problems it has caused.)
Use the right gasoline and you'll make more power than E85.

Seriously, if you would like to talk about this in detail, I'll be happy to help: send me an email with your data and exact setups you ran each fuel.

Steve Lepper wrote:

Bill Schenker wrote:
I've got multiple dyno graphs, both for VP MS 109 & E85 vs. 91 octane that say otherwise!

Says the guy who can't keep valves in his engine... ;)

There's your problem: 109 is too much octane (slow flame travel) and 91 is not enough. Also, I would also stay away from oxygenated race fuel (hint: I can show you valve problems it has caused.)
Use the right gasoline and you'll make more power than E85.

Seriously, if you would like to talk about this in detail, I'll be happy to help: send me an email with your data and exact setups you ran each fuel.

Says the guy that makes 165-185whp, depending on the dyno, from a CSP-legal motor. The valve problems (only the intake valves) were due to the VVT intake cam not being controlled properly - I was getting wicked valve bounce.

Steve, I've also ran 100 octane, in addition to 91. Results: 91=100, but just costs a lot more. E85=VP MS109 which gave me a 5% bump across the entire band compared to 91/100. In the case of the E85/109, the reason I went to those fuels was FOR the high O2 levels - the octane was a non-factor; I don't have the compression to benefit from it.

I'm making ~205hp @ the crank w/basically a stock motor - well-built, but other than the pistons, which really don't give you much, a "stock" motor. That's 65hp over stock. Obviously, all the peripherals are what make the difference: well-tuned ECU; dyno-tuned intake length, excellent exhaust manifold, etc., etc.

There's fuel out there that can do better than that?! Show me the Golden Path, Steve!

Bill Schenker wrote: There's fuel out there that can do better than that?! Show me the Golden Path, Steve!

maybe VP C44.

BTW i think the 44 is the dollars per gallon not octane.