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-   -   setting a carb for e85? (http://www.hotrodders.com/forum/setting-carb-e85-106947.html)

brian12c 01-17-2007 01:27 PM

setting a carb for e85?
 
Ive read that e85 fuel has an octane rating of 105. This stuff is available everywhere now here in Missouri and sounds like it could be a great cheap race fuel. Does anyone have any tips on setting a carb to run it? are there any dangers to running it in a race motor? Whats the compression limit for 105 octane? thanks a lot, BF

johnsongrass1 01-17-2007 01:48 PM

You won't find a lot of info about this at your local racers club because those who know ain't talkin.

Essentially, you will need to rework the air bleeds, the metering block, PV restriction, the venturi's, and the N&S needs to be all metal. A big pump is needed as well.

If your under class sanction, talk to a specialty carb builder and listen to them. Your gonna pay for it though, I'll warn ya.

E85 on the street is pretty much pointless because of the mileage concerns. Even running 12:1 compression on E85 won't get your mileage back. It ends up costing a lot for little gains.

curtis73 01-17-2007 01:57 PM

It takes about 30% more fuel to be the right mix, and it has a large percentage less BTUs per pound.

Car Craft or Hot Rod did a complete side-by-side test on gas vs. e85. They did an apples-to-apples test on the same motor set up with 9.5:1 on pump gas, and then 12.5:1 on E85. They burned 30% more fuel and made the same power.

So, race gas yes because it can handle high compression, but not race gas from the standpoint of super high performance.

Pianoman 01-17-2007 02:19 PM

Odd. Iīve seen dyno runs clearly resulting in higher hp on E85. Just higher compression alone is not enough. The timing both advance and curve will most likely be subject to modifications

johnsongrass1 01-17-2007 02:28 PM

No timing adjustment. Timing is based on head chamber config and not type of fuel.

Power gain were to had with E85 and compression, but not enough to warrent the $1000 your gonna spend on the carb alone and the mileage decreases.

RippinRon 01-17-2007 03:09 PM

Its the same idea as LPG (propane) yes it has a higher octane rating but the BTUs are lower. Heres a link to some BTU values.

alittle1 01-17-2007 03:16 PM

Quote:

Originally Posted by curtis73
Car Craft They burned 30% more fuel and made the same power.

So, race gas yes because it can handle high compression, but not race gas from the standpoint of super high performance.


Curtis, Perhaps you should go back and read the articles in the past two months of CARCRAFT. If you can't get the news stand copy, then go online to www.carcraft.com.

Uses more fuel, makes big power. E85 is great for the weekend racer.

curtis73 01-17-2007 09:21 PM

Quote:

Originally Posted by alittle1
Curtis, Perhaps you should go back and read the articles in the past two months of CARCRAFT. If you can't get the news stand copy, then go online to www.carcraft.com.

Uses more fuel, makes big power. E85 is great for the weekend racer.

The article to which I was referring made 6 more hp on the dyno. I'm not an expert, I was just quoting an article from a magazine. IIRC it was a 360-hp 355 that made 366 after the whole kit and caboodle. Proper timing, cooler plugs, the works.

The fact is, E85 has fewer BTUs than gasoline. Gasoline weighs in at 114,000 BTUs per US gallon, Ethanol comes in at 76,000. So, E85 would be around 81,700 BTUs if my head did the numbers right. E85 therefore has 28% less energy and requires about 30% more fuel. Sounds like a wash to me. The higher compression does tend to make better use of the BTUs in ethanol, which accounts for the modest gains in power in most of the apples-to-apples tests I have seen.

It CAN mean big power, but no more than gasoline if you're comparing apples to apples.

Pianoman 01-18-2007 12:15 PM

Quote:

Originally Posted by johnsongrass1
No timing adjustment. Timing is based on head chamber config and not type of fuel.

Power gain were to had with E85 and compression, but not enough to warrent the $1000 your gonna spend on the carb alone and the mileage decreases.

Oh great. So Iīll just run on the same timing on low octane as on race fuel? Brilliant... :rolleyes:
Why would I wanna spend 1000$ on the carb when my buddys carbīs been runnig great with E85 for 3 years? Could it be broken but not knowing it? :drunk:

johnsongrass1 01-19-2007 10:11 AM

Yes exactly, the same timing.

Gas, alky, methonal, E85, nitro, whatever, I've have, or my buddies have used it all these at some point. 36' timing

If your using race gas then and moving timing your wasting money. Octane does NOT make power. Compression does.


Your from Sweden, and not here in the land of the free, so I can't tell you about your carb since your fuel requirement's are not the same as ours.

I can tell you that when you switch to our street gas to E85 my carb builder, I might he is the best in the buisiness, will charge you close to $1000 to convert.

Hogg 01-19-2007 11:04 AM

Quote:

Originally Posted by johnsongrass1
Yes exactly, the same timing.

Gas, alky, methonal, E85, nitro, whatever, I've have, or my buddies have used it all these at some point. 36' timing

If your using race gas then and moving timing your wasting money. Octane does NOT make power. Compression does.


Your from Sweden, and not here in the land of the free, so I can't tell you about your carb since your fuel requirement's are not the same as ours.

I can tell you that when you switch to our street gas to E85 my carb builder, I might he is the best in the buisiness, will charge you close to $1000 to convert.

Using high octane ALLOWS you to use more timing and possibly get more power.

if you are getting 400 hp with 32° of timing on 87 octane, then you add 104 octane unleaded race fuel and that race fuel allows you to run 36° of timing. if your setup makes more power with more timing, then you WILL make more power by advancing the timing.

I agree with you, higher octane fuel alone doesnt make more power, actually it makes less, but the extra slower burning high octane fuel allows you to advance timing to make more power. As well as using more compression, leaner a/f ratio etc etc.

peace
Hog

johnsongrass1 01-19-2007 02:38 PM

Your wrong,

I'll leave it at that.

Pianoman 01-19-2007 04:49 PM

Quote:

Originally Posted by johnsongrass1
No timing adjustment. Timing is based on head chamber config and not type of fuel.

Really? Poor guys thatīs spent hundreds of dollars on tuning their cars for high octane gas. Funny the cars are going faster though.. :confused:

coldknock 01-19-2007 06:31 PM

I think what he's getting at is that if you see a power gain from better fuel and more timing then your combination was poorly matched to start with. I agree with that.

As for E85, it alone does not make more power. It allows you to use a higher compression ratio/tolerate higher cylinder pressure. That combined with the proper combination of parts to suit will make more power. It's all relative to the combination and the type of fuel used is a part of the combination.


Larry

paulo 1 01-19-2007 07:44 PM

I do not want to sound cocky,but I am writing from the land where ethanol has being available at the pumps since late 70s.In the 80s more than 70% of new cars sold here by Chevrolet,Ford,VW,Fiat were alky burners.We do have quite an experience with this fuel.

Power: An engine can be tuned to duplicate and sometimes exceed the power of the gasoline version.

Driveability: Expect 3 times the warm-up time necessary until you can drive it.Use a hotter thermostat.Partially block the radiator if the engine runs too cool.

Cold start: It will not start bellow 60 F,unless you have the help of gasoline.Without heat rise ,will freeze the induction bellow the venturis.

Corrosion: Sending units,tanks,pumps,lines,carbs have to be protected by nickel.Will not corrode cylinders,pistons,rings,valves etc.

Pollution: Can be made to pollute less on HC and CO.Will release uncommon pollutants like acetone.Overall it is a clean fuel.

Timing: All engines respond better to more static advance and less total.Flame front velocity is slower.Could use cooler spark plugs if compression is raised.Same gap.

Rule of a thumb to modify existing carb:All calibrated fuel passages should be enlarged about 35%.Accelerator pump must squirt for a longer time.All calibrated air passages must also be enlarged around 15%.If the oil becomes
milky it is too rich.Use the same fuel bow level and fuel pressure.

If your line of work involves physical contact with fuel you will never want to deal with gasoline again.It is a fun fuel.Good luck.


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