64 replies to this topic

[86rustbox]

so i'm thinking about converting over to run ethanol on my carb'd dx. i know it's not too terribly difficult on more common carbs, some mix adjustments and possibly rejetting. but as i've found, jets aren't really available for honda carbs anymore. plus, i'm not sure our ONE idle mix adjust would be enough change for the ethanol. if found a place that will rejet our carbs to fit holley jets, but it's $250 (that's along with a full rebuild). probably easier to go weber.

i have a few things to consider, among them performance...well mainly that. i autocross and plan to club race, so i don't want to sacrifice any HP, torque, or engine response. i've read that with the right setup ethanol can yield better results.

just trying to be a little greener about my racing...

tips? thoughts?

[icebox187]

fuel lines have to be stainless steel i think, and rubber doesnt hold up well, so i would look into the gaskets and seals in your carb. i dont know what compression you're currently running, but ethanol apparently likes higher comp ratios. seems i read somewhere that the pistons actually had to be coated with something. alcohols tend to leave a nasty residue thats known to clog things up, especially in p-3 orion water/alcohol windshield washer systems (ask me how i know)... what i mean by all this is combustion isnt the problem, it's fluid compatability

[86rustbox]

fuel lines have to be stainless steel i think, and rubber doesnt hold up well, so i would look into the gaskets and seals in your carb. i dont know what compression you're currently running, but ethanol apparently likes higher comp ratios. seems i read somewhere that the pistons actually had to be coated with something. alcohols tend to leave a nasty residue thats known to clog things up, especially in p-3 orion water/alcohol windshield washer systems (ask me how i know)... what i mean by all this is combustion isnt the problem, it's fluid compatability

there's so many different opinions and research on the compatibility of it all. i read that all newer rubber gaskets and hoses can withstand ethanol, since it's been 10% in our fuel since the late 70's, and that it leaves less build up in the engine that gas; which i can totally believe...it's almost a solvent.

ANYWAY, yeah i've heard higher compression ratios work better...which could benefit me in this case. i have the CVCC head which is supposed to have the highest comp ratio next to the CDM head. i wonder, would the pre-combustion chamber of the CVCC head would help the igniting of the ethanol?

[zakats]

rather than delve too deeply (I'm multitasking) in this, I'll just state a few things for your consideration.

-Ethanol (80% gasoline?) is something like 104 octane
-Your compression ratio is very low (under 9:1) thus can't use the full potential of the higher octane or even close
-Ethanol has less energy than 100% gasoline and will make less HP- pretty much no matter what you do, you won't make as much power as you would if you were using gasoline instead (all other things being equal)


A great idea if you want to up your compression to around 11-12:1+ and not have to buy race gas with an aggressive tune (meaning you can probably get away with as much as 12:1 on 93 just not with a lot of timing)



pretty much no matter how you look at it, cvcc isn't good for performance if it was, it would still be employed by manufacturers and big budget racing teams

[86rustbox]

rather than delve too deeply (I'm multitasking) in this, I'll just state a few things for your consideration.

-Ethanol (80% gasoline?) is something like 104 octane
-Your compression ratio is very low (under 9:1) thus can't use the full potential of the higher octane or even close
-Ethanol has less energy than 100% gasoline and will make less HP- pretty much no matter what you do, you won't make as much power as you would if you were using gasoline instead (all other things being equal)


A great idea if you want to up your compression to around 11-12:1+ and not have to buy race gas with an aggressive tune (meaning you can probably get away with as much as 12:1 on 93 just not with a lot of timing)



pretty much no matter how you look at it, cvcc isn't good for performance if it was, it would still be employed by manufacturers and big budget racing teams

i thought i'd be able to at least get the same performance out of it just by delivering more fuel, but the compression has to be that different? flex fuel vehicles don't change compression when filled with ethanol, just basically introduce more fuel...because yes, ethanol has less energy. as far as i know they don't have a difference in HP between fuels.

it is a known fact that CVCC isn't awesomely performing, but i have a budget to adhere to and racing classes to abide by; that's probably the same reason many club racers and autoxers in old, underpowered carb'd cars don't just do swaps.

how much would i have to shave the head to get 11-12:1 compression? i'm only allowed a certain amount, can't remember what it is at the moment.

Edited by 86rustbox, 02 August 2009 - 04:10 PM.

[C8V6C]

I've considered doing this since 100oct is still $5.99 a gallon...seriously.

[zakats]

i thought i'd be able to at least get the same performance out of it just by delivering more fuel, but the compression has to be that different? flex fuel vehicles don't change compression when filled with ethanol, just basically introduce more fuel...because yes, ethanol has less energy. as far as i know they don't have a difference in HP between fuels.

it is a known fact that CVCC isn't awesomely performing, but i have a budget to adhere to and racing classes to abide by; that's probably the same reason many club racers and autoxers in old, underpowered carb'd cars don't just do swaps.

how much would i have to shave the head to get 11-12:1 compression? i'm only allowed a certain amount, can't remember what it is at the moment.

Like I said, all things considered equal (or at least relatively) as in air flow (cam, carburetor size, intake manifold flow), % of fuel added to stoichiometric (14.7:1 for gasoline, ~15.4:1 for propane, ? for ethanol), timing advance...etc

Sure you can add more fuel but it isn't going to run efficiently and you would have the same effect as just running rich with gas.

You would probably have to mill the head lower than the valves could handle in order to get anywhere near 11:1 you would have to run pg6 or p29 pistons to get in that range. I'm working on getting compression numbers together for the wiki and I ran across a legit racer's post that stated a static comp ratio of about 11.2:1 with your block, p29 pistons, and an Si head (larger cc dome resulting in lower comp ratio).

BTW you're way better off with a weber single downdraft since they go for around $300-350 for the kit, offer more performance, are more adaptable, and are not 20+ year old economy designs. If your budget and rules allow for it, I'd highly recommend it.

I've read that some flex fuel cars run a little extra rich so that the driver doesn't notice the change in fuel but it is still noticeable. Ethanol has the luxury of high octane but isn't ideal for a naturally aspirated setup that you want to make power out of.

I've considered doing this since 100oct is still $5.99 a gallon...seriously.

you're probably better off with propane, 114 octane why better? because I'm tickled with the idea and it is probably more magazine worthy

[firstgencrx]

OK, my two pennies....

Stoichiometric for E85 is something close to 9.75:1, I'll need to look it up to be sure, but it's close. For making serious horsepower, you end up tuning somewhere around 7:1 to 7.5:1.

When your engine is tuned for it, you can actually make more HP from E85, but at the cost of more fuel usage (close to double). It's not just the octane rating that makes it a good racing fuel, it's also the cooling properties of the fuel. The alcohol dragster guys have known this forever.

To take real advantage of E85 (to make real power), you need lots of compression. 18/20 to 1 is not unheard of for an NA motor running E85. The problem with compression ratios that high on a motor is the top end clearances. It's really tough to build an engine with those kinds of tight clearances without parts banging into each other. Where E85 is more popular is with the boost crowd. It's not uncommon to find engines with 11/12 to 1 compression, running E85 with boost without a compression reduction. It's very doable. Of course, boost with a lower compression engine is always better.

David

Note: I'm seriously looking at E85 for my little H22 project, combined with a little EATON M62. That would be cool!

[zakats]

I suppose that makes sense if one volume gasoline has more energy than the same volume of ethanol... but by having the luxury of tossing a lot more volume of ethanol and staying near stoich, you're allowed to compensate for the lower energy/volume... never thought of it that way.

[icebox187]

every heads up article i have read so far has made more power with ethanol when tuned for it. get a good wideband.

[86rustbox]

Like I said, all things considered equal (or at least relatively) as in air flow (cam, carburetor size, intake manifold flow), % of fuel added to stoichiometric (14.7:1 for gasoline, ~15.4:1 for propane, ? for ethanol), timing advance...etc

Sure you can add more fuel but it isn't going to run efficiently and you would have the same effect as just running rich with gas.

You would probably have to mill the head lower than the valves could handle in order to get anywhere near 11:1 you would have to run pg6 or p29 pistons to get in that range. I'm working on getting compression numbers together for the wiki and I ran across a legit racer's post that stated a static comp ratio of about 11.2:1 with your block, p29 pistons, and an Si head (larger cc dome resulting in lower comp ratio).

BTW you're way better off with a weber single downdraft since they go for around $300-350 for the kit, offer more performance, are more adaptable, and are not 20+ year old economy designs. If your budget and rules allow for it, I'd highly recommend it.

I've read that some flex fuel cars run a little extra rich so that the driver doesn't notice the change in fuel but it is still noticeable. Ethanol has the luxury of high octane but isn't ideal for a naturally aspirated setup that you want to make power out of.


you're probably better off with propane, 114 octane why better? because I'm tickled with the idea and it is probably more magazine worthy

i would like a weber single downdraft and ITC class rules allow it. gotta have the dough though.

what are p29 pistons and how can i get them?

if found this one place that has .040 over forged pistons for carb and FI http://rivergate5spe.../rivergate.html. dont' know if any of those would be p29's or pg6's.

and thanks for yer input everyone...i read that with tuning you could get decent ethanol results; just didn't know it would be that much tuning.

Edited by 86rustbox, 03 August 2009 - 09:40 AM.

[Screech]

When your engine is tuned for it, you can actually make more HP from E85, but at the cost of more fuel usage (close to double). It's not just the octane rating that makes it a good racing fuel, it's also the cooling properties of the fuel. The alcohol dragster guys have known this forever.

Very true. My big boss here ran an alcohol dragster and said the engine was cooler at the finish than at the start.

[firstgencrx]

Very true. My big boss here ran an alcohol dragster and said the engine was cooler at the finish than at the start.

A lot of the alcohol dragster engines didn't even have water jackets in the billet aluminum blocks or heads! I didn't believe it myself until I saw one of the engines with my own eyes. The guy said if he needed more cooling, he just ran it richer. Said the richer mix had little effect on power, but a lean mix would mean certain melt-down.....

[C8V6C]

I know its not the same circumstances as the OP, but my tuner/builder/friend said that my 9.0.1 compression should be find with a new tune.

We will burn more gas, but I still think we would be miles away from 5.99 a gallon which is seriously getting old, now that gas prices have dropped half price, but 100oct has stayed the same for over a year

[86rustbox]

I know its not the same circumstances as the OP, but my tuner/builder/friend said that my 9.0.1 compression should be find with a new tune.

We will burn more gas, but I still think we would be miles away from 5.99 a gallon which is seriously getting old, now that gas prices have dropped half price, but 100oct has stayed the same for over a year

but you're running FI, a b-series right? did he think e85 would be okay with the carb'd cars too?

that was what i was thinking about burning a little more ethanol, it's cheaper compared to race fuel AND burning more is still using less fossil fuels.

i'm out for the rest of this race season anyway...i might try a couple of gallons of it along with a tune, drilling my jets, some ignition timing adjustments and see how it performs...tossing ideas around is informative, but i'll never really know till i try.