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Post by outplayedu on Jan 9, 2011 14:41:16 GMT -5
first off i'm completely new to the e85 thing other than the hours of research i've done.
i'm building a 12.5-1 385 sbc for a mud bogger,and other than traveling to get it,e85 is going to be the most feasible option for fuel(race fuel is around $12.00 a gallon here,i can drive an hour and a half and buy e85 for $2.71).
somy first question for you guys is has anyone here converted a predator to run on e85?it looks like you do an alcohol conversion,then run a #3 cam from the limited info i've seen.
if the predator is a bad idea,does anyone have a used e85 carb for sale in the 850-1050 range?thanks for any input.jeremy
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Post by adamsvega on Jan 9, 2011 17:48:44 GMT -5
well you need to change the internal passage less than the methanol conversion kit has and get the new alky acell pump and bowl extension .
i doubt that the number 3 cam (15%) isn't enough and that would give you a big hole in the fuel curve off idle-3000 rpm . having you clamp down on the door tension to get the mid range accel back up. then you would still be chasing lean as even-though predator calibrations are notoriously .5 rich on the afr .
i would think a call to Dale is in order for a alky kit and go about 1/2 as much on the drill size . the spray bar is your main mixture control and if you went about 15-20% bigger area holes and used the #3 cam this would be my best guess kinda thinking.
if you step up to a#7 cam you will most certainly be lean off idle till ya get on the cam and the doors will need to be tightened . your going to have to play with it and see what way gets you to let the air doors open as fast as needed by cfm and not to control rich lean as a crutch.
some of the small motor , tight converter /gear cars actually like the bigger cam and smaller bar on alky as they dont need the cfm anyway your on the bubble at 385 .
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Post by butterbean on Jan 10, 2011 10:04:17 GMT -5
outplytedu, Adam is the man to have reply about tuning we all use him  but where are you located and what kind of mud bogger are you building? I also build mud trucks as well as drag cars and this site is by far the best to learn about e-85 hands down!!!! |
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Post by outplayedu on Jan 10, 2011 19:55:43 GMT -5
thanks so much for the replys.i'm in southern maine.our home track is godeepmud(should check out the website).
my newest rig is a 73 jeepster commando on 2 1/2 tons with 6.72 gears.drivetrain is a 385 cube sbc,dart 230 iron eagle heads with 49cc chambers,all forged internally balanced rotating assembly,solid roller cam,bowtie intake,accell 300 plus ignition,turbo 350 w 10" converter,and a fixed yoke 205 case.should be quite a terror in the 44" dot class.
as intriguing as the predator is,i'm thinking that for a new e85 user like myself i'll stick to a conventional style carb.anyone have an opinion on 4150 vs. 4500 for this combo?
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Post by adamsvega on Jan 10, 2011 20:16:42 GMT -5
i guess what i really need to know is what rpm are you cranking ? and does it get loaded down hard at wide open throttle .if so you may give up a little top end on a dyno with a really big 4150 but the throttle response and down low tq curve will be better and mix better with the smaller venturi and anular boosters .if this was a lite drag car with a 5500+ stall then a small dominator would be good . my best guess is the 900-1000 cfm 4150 .
can you run mech. fuel injection? i can set you up with small bore toilet and you'll get both worlds
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Post by outplayedu on Jan 12, 2011 17:00:23 GMT -5
as far as rpms,shifts should be between 7200 and 7400.rev limiter set around 7600.depending on the track it can definately see a tremendous load at wot.
cam is .607/.615 with 1.5 rockers.duration at .050 is 260/270 ground on a 104.i know its not the ideal cam,but i own it already and it will still pull decent.cam upgrades and head porting will wait until next year,other wise i'll never financially get it finished for april.
anything below 4000rpm is pretty much not a concern as the only time it sees rpms below that is leaving the line,and even then its pretty much hit the converter around 3800 and tear ass in a no hook full spin situation.high gear max rpm is what i want.moving mud from in front of the tire to behind it is what propels a mud truck so wheel speed is where its at.
i know they're not super accurate,but with my exact combo dialed in on desktop dyno its showing 567 hp at 6500 and 516 ft lbs at 5000.torque is over 400 from 2500 to 7000,and its still showing over 550 hp at 7500.this is all with a 1050 cfm carb.you can shuffle the hp and torque around with carb size just as adam said.
i don't want to put to much faith in the dyno program so i'm on the fence as to carb choice.
until i move up to tractor tires,no aftermarket injection is allowed unfortunately.
*correction,theres no rule on injection,just no blowers,nitrous or turbos.
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Post by adamsvega on Jan 13, 2011 7:05:12 GMT -5
if your up in the rpm that high the whole pass i would barrow a set of 1.6 1.65 rockers and play or plug in your rocker arm changes to the computer (fudge lift and duration if old program to mimic) and see. go with the biggest 4150 based flow you can get .
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Post by outplayedu on Jan 14, 2011 22:33:40 GMT -5
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Post by adamsvega on Jan 15, 2011 6:59:07 GMT -5
thats the guy i buy my small parts from now ......didn't know he was e-85 building ...hummmm
. the 750 dominator imo is just to look cool
.with all the high flow std holleys now it is alittle obscure . but if you have one a little inspection of its dimensions and part numbers will show if it is worth converting . i would imagine you would end up with real big gas block,e-85, or have those reamed open then size the booster accordingly
basically downsize a e85 big dom this is all speculation as i have NEVER opened up a 750DOM maybe you could have it opened up in the bore and get like 900cfm and the ease of a dom.
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Post by outplayedu on Jan 15, 2011 11:35:02 GMT -5
this is the dominator in question. www.holley.com/0-80186-2BK.aspsame venturi and bore size as a 1050 i think. a local racer has a reman in the box.after having it converted i'd be right around the same money as the carb i posted from rpm. |
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but where are you located and what kind of mud bogger are you building? I also build mud trucks as well as drag cars and this site is by far the best to learn about e-85 hands down!!!!