E85 Conversion (carb)

that sounds about right for the differences in gas mileage, but i'm surprised e85 is $1 less than premium...in st. louis its only about 65-75 cents less.

and oh yeah, it's alive! on ethanol. besides drilling the jets i upped the idle mix from 2.5 turns out to 4.5 as well as increasing the idle a bit, and changing the ignition timing...not sure if i advanced or retarded it. i messed with it until it ran smoother, which ended up being a few degrees counter clockwise. it idles the way it did before and seems to have relatively the same accel, but i haven't gotten on it all the way, just around the block. my new side-exit exhaust is hitting the rocker panel and makes an annoying clang at about 3500 rpm, so i'm off to fix that and then i'll take it for a proper spin.

Edited by 86rustbox, 14 August 2009 - 02:15 PM.

clockwise... looking at it from the dist cap side? if so that would be CCW from the crank pulley side and since this is a CCW engine- you do the math, I'm going to bed!

uhhh...yeah then i think i advanced it?

i finished up the exhaust and took it out for a spin, stopping to play with the idle a few times. it ran great, really smooth under accel but i still have my rough idle problem that i had with regular gas. i didn't seem to lose any power, hit 95mph by the end of the on ramp lane on the highway with ease. it seemed to have more power in the high rpm band, like above 4500rpm.

cold starting seems to be a little hard, and it wasn't even very cold (like 70F). once it's warmed up i don't need to choke and it idles regular, but when i first start it i can choke the shit out of it and it still won't stay running without my foot on the pedal for the first few minutes of driving. taking this into consideration for the colder season i've been thinkin of some way to run the idle adjustment into the cabin. the idle screw points towards the firewall already so that's a good place to start.

any ideas?

oh yeah and i think somewhere back in this thread i said it died out when i turned sharp lefts and ran rich on rights...well it's the other way around (i hadn't driven the car in a while). dies out on rights and i know the fuel pickup is at the bottom right of the float bowl, so i think maybe my float needle may be a little whack. it didn't do this till i replaced it in a rebuild, now that i think about it. i'm thinking of putting the old one back in and seeing what happens.

I can't comment on the rich/lean issue as it has been a few years since I last pulled a carb apart.

I am envious of your weather, houston is still hot and muggy in a way that makes a steam room seem mild.

There are two (I believe) idle "bumps" on the original carburetor that allow the original nest of vacuum bullshit to punch up the idle and are actuated by... you guessed it, vacuum! I believe that you could adjust one to your desired setting and have either an electronic actuated vacuum valve turn on/off the function of high idle or remove one of the aforementioned diaphragms and pick up a small servo from an electronics store (you'll need to find a place a little more hardcore than radio shack!) that will operate on 12v dc to be mounted in favor of the original vacuum diaphragm.... you get the idea. I'm planning on doing this when I get my a/c setup sorted out

ha! that might be why my idle doesn't hold, i removed all that crap with the devac. that would kind of explain the carbs inability to correct itself during idle dips. the electronic servo seems like a good idea, but does it just have one "boost" level? what type of electronics store would have one? i'd like it to be adjustable for different weather conditions, especially with e85's cold weather starting issues. there's some linkage you mentioned left on the drivers side of the carb from the diaphragms, maybe i could utilize that in some type of cable or linkage system into the cabin. electronic or not, it'd be nice not to have to turn my actual idle screw and mess up the setting every day.

bummer, i can't really look at it now, it's a monsoon outside.

and st. louis IS hot and muggy, we just have a few cool mornings here and there.

Edited by 86rustbox, 17 August 2009 - 04:57 PM.

I don't believe there is a 'smart' idle function for the idle boost with the vac crap, I'd say it is only for the alternator and a/c boost functions... to speculate. There should be two diaphragms- one on the driver side, one on the passenger side. I think you could have a knob of sorts to adjust the amount of juice the servo would get but a cable would also do... but you would have the pain of making bracketing/cable and adjustments... you might just look into running your throttle cable and a secondary cable to a module under the bay that has three throttle arms- two for your gas pedal/secondary cable (mounted next to your seat that is distinguishable via lever and screw adjustment-think about the cable adjustment bracket at the carburetor) and a third to go from the module to the carburetor. The throttle arm used for your

I've thought about doing this for a sort of ghetto cruise control device and the servo thing as an a/c idle boost for my devac'd car... I think the cable idea will work for your case, I just didn't want to do it with a/c because it would require constant fiddling if I happen to be idling.

The more I think of it, the more I think that you just need more fuel for your idle circuit though I don't have much real experience modifying carburetors.

here in houston there is little to no mercy, consider yourself lucky!

as i remember the linkage on the drivers side has a little less resistance than the main throttle return so i may start there as a cable trial idea, though that may be the secondary linkage...but i don't think it matters. a little more fuel is a little more fuel any way you look at it. about the bracketing trouble, i could start with the diaphragm and bracket for the drivers side and modify it so it works via cable instead of vac. i think i still have em lying around.

not a bad idea for the cruise, but you'd have to be on a mostly flat surface the whole time, since there wouldn't be any adjusting it unless you're going to fuss with it while you're moving. well, you could just set it for the flat surfaces and use the pedal to maintain up hills i guess.

i may need more fuel for my idle circuit. maybe i'd drill the idle jet if i knew which one it was...there's four total; two largest i've drilled, two smaller ones are labeled "38" and "40". i don't know which one is third bbl and which is idle.

Your idle issue when the car is cold will def. be attributed to E-85. I'm not saying it's 100% of your problem.
One of E-85's properties is that it won't perform well cold. I don't know why... IIRC, the new flexfuel vehicles have an in-line fuel heater as a work-around.

yeah i know part of it is e-85, but part of the cold idle prob was there before...probably didn't help that i took off the vac idle boost. it definitely got worse with e-85 though. precisely why i need something to jack it up till the engine gets warm, choking just isn't enough.

i'm sure that the small radiator line running in the back of the carb, the baseplate warmer, helps the e-85 warm up faster; but probably not as good as a proper fuel warmer...though i'm not sure how they work.

the ones ive seen (for running vegi oil in diesel) is basically a heat sink wrapped around a fuel filter, but with a heat pipe (coolant line) wrapped around the heat sink. the heat sink isnt used for cooling, but transfering the heat from the pipe since it conducts so well.

thanks kaymo, but my warming up phase as of now lasts about as long as it would take the coolant to heat my fuel line. it's only 1 min or so before i can just choke it a bit and let off the gas. but who knows, maybe i'll need something like that in the winter.

just wondering...would p29's work with the CVCC head? if i have the money for one or the other to start (p29's or an SI head) i'd probably go with p's if they'll work. i wouldn't want the drastic drop in comp just slapping an SI head on there with DX pistons, especially since i'm running e85 now. the main problem i can think of would be the p29 dome hitting the CVCC chamber.

I don't know if you'll have interference with the quench pad but I'd assume you would since the pad is at equal height with the mounting surface of the head and the top of the piston dome. I think the best upgrade would also be the simplest- find someone with stock pistons and rods from an Si, I venture to bet that the stock EW5's used this setup so it should be safe (I would think). If your class allows for it, I STRONGLY recommend you just put off changing your setup until you can save the money needed to do both at the same time.
My setup that I am currently building is an EW block, brown top (pg6's), Si head- Due to my using aftermarket pistons, I am having the engine balanced and spending about triple what I would if I didn't have it balanced! From a few, reputable sources (racers like JSGprod and Keithg- the owner of HASport!) I have concluded that the p29's with Si head will need to be cut in order to clear a "big" cam while the brown tops do not. I didn't buy my pistons so I didn't have much say so in what I ended up with but since you want the most compression possible, you will be best suited to just take the time and clearance the piston tops and invest a little more for the extra gain.

Bore, hone, press in/out, tank, and balancing is going to cost me $260 (best price I could find) and should be well worth it IMO. Parts will vary for you- the pistons will cost something like $80-90 shipped, head $60-120 (there is a guy in cali selling 2 COMPLETE Si's for $20/each so you could get some parts cheap if you can convince him to strip one and ship its gutts), and your other normal rebuild items that you might as well do while you're in there.
Take your time and do it right; that's my vote.

that's exactly what i was thinking about the p29/CVCC combo. so stock SI pistons and rods w/my head would give me a little higher comp because they're designed to make up for the lack of a quench pad, right?

i'd like to just do p29/SI head but we'll see how much dough at the time of the rebuild. i've got other regular maintenance stuff like CV axles and rear shocks coming up soon too.

Sort of, but they result in a 8.7:1 CR, lower than the stock DX
I thought you meant using the Si pistons and Si head- yes, I believe you should end up with something along the lines of 9.7:1 which is better, but still very far from ideal... actually, I think it is just as much of a waste of time now that I think of it.


sit on it, the end result will be well worth it.
check ebay for the shocks, I bought a set of new monroe's for ~$20 by a "make offer" gig since nobody seemed to want them
CV's, there ought to be more than a few floating around for a couple cheeseburgers+shipping
I've given away a bunch since they're practically worthless




http://www.redpepper...e...c=44972&hl=

Edited by zakats, 21 August 2009 - 01:41 AM.