The Dodge Challenger Message Board

any body have or done the latest fuel injection on a 440? if so how is it working?

Not yet, I have a trip to complete! Here's the 'latest' 440 bolt on F.I. system with dual sync dizzy& T.B.I.,,pricey but user friendly and fully adjustable www.fastmanefi.com or this one www.mass-floefi.com The T.B.I. systems arent as efficient as a M.P.I. becuse the intake manifold is still 'wet' The Mass air flows are the easiest to use for any engine application without cumbersome tuning as required with Speed Density systems. Most are NOT true sequential even though they say it. There is no way to 'squirt' that much fuel into a cylinder with only 30 degrees in every 720 degrees at 6000 RPM's. As the engine speed increases the system reverts back to the simple firing order to squirt the fuel. True seqential is only beneficial for direct injection or emissions concerns. TBI systems only offer improved starting and low speed driveablitiy ,,nothing for performance over a well tuned carburetor(s).

so they still dont have a performance gain, but the do offer a little more reliability over a carb, i still cant find my innovate tech unit it may have been lost in the move 3 years ago i spent a part of the weekend looking for it and i hope i can find it so i can tune my carb a little better it seems like when im on the hiway and get it to about 3 or 4 grand let off the throttle and hit it again i am getting a stumble i may need to change the power valve , i am using a demon 750 and the fuel is still getting hot ill post a pic later today to show you my current set up and see what you guys think

I'm no carb expert Drew, I know Dave can give a much better recommendation. But I think at that speed the vacum wouldnt be that low plus during de-celleration the vacum is at the engines highest level, followed by cruise, followed by idling. On the flip side WOT the vacum drops to near zero, followed by part throttle acceleration. Of course we all know the power valve is supposed to open when the vacum drops to the specified PV number X 2. Youre not alone. At cruising speeds my R/T is experiencing a slight miss, at WOT it's just fine and the transitions in between,, just at cruising speeds and it does it intermittently. I think I need to enrichen that circuit a bit. It was 93 degrees with 84% Humidity, Heat soak or fuel boiling hasnt been an issue with me just yet, I use a fuel vapor seperator and a return line back to the tank, Hemi, Carter Mechanical Fuel Pump, 94 Sunoco. The fuel Injected engines dont experience the heat soak problems due to much higher pressures. Throttle body systems are 15-20 PSI. Multi-Point are 45-60 PSI at these presures fuel boiling isnt an issue. Throttle Bodies that inject fuel or Throttle Body Injection are simply electronic carburetors but without all the tuning features that a Demon like your's has. So NO gain there and it's very expensive. Multi-Point F.I. systems are way better and make superior torque over a carbed engine and make more power under the curve. Peak Power is the same but the throttle response and everything else is superior. I thought you had an electric pump in the rear Drew?

I just hope I dont screw mine up so bad that Poor Dave & Bob spend the time working on my Six-Pack setup!

Sounds to me that your pump shots might be too big.

I would first check that the carb is not running too rich at those rpms. Just in case the pump shot is OK but on top of an already rich mixture is too great.

If you cruise mixture is OK try dropping down on the pump shot (size and or duration) until you have just enough to remove any bog when flooring it from a standstill.

ok are you talking about the accelerator pump? because i do have a bog when i start out,i have gone to a smaller size on the power valve do need to go smaller power valve? im wondering if i need a new one anyway its a demon single carb and i do remember having a back fire a while ago per haps i will orde several sizes and try that thanks guys

drewcrane wrote:ok are you talking about the accelerator pump? because i do have a bog when i start out,

Yes. Maybe it is too big (too big can make the engine bog the same as too small) or maybe you have a combination of problems such as too high a rated power valve (so you need more pump shot when you floor it from a standstill) but then the pump shot is too much for when you floor it at 3K+.

I think you need to start at basics and tune the timing, idle mixture and primaries.

I think you need to start at basics and tune the timing, idle mixture and primaries. yes that is my plan some time this week is to start all over i talked to a couple of people it seems they changed the fuel this year because they have the same problem, ran fine last year, and this year it seems to rich and has some issues that it did not have when i tuned it about a year ago,thanks again i will post the results soon

Hey Drew, when you got your Demon carb did you Jet it for Denvers 5000+ feet above sea level elevation?

We haven't got mountain tops that high above sea level in England.

Yeah, I remember my bud pulling over his 69 Charger R/T 440 and changing or fiddling with his carbs leaving or entering Denver a long time ago. It cleared up a while later. We dont plan on being in Denver that long eh Dave. Plus we always have the outboards to enrichen the mixture right?

Eddie, I looked at that mass-flo efi, and was impressed by their claims. For a drop on multi-port, it is remarkably simple. I also was looking at Edelbrock's pro-flo kit. Not a drop-on EFI setup, but it appeared to be reasonably priced and easy enough to allow me to install it. Have you seen this kit?

They claim fully sequential(Eds Pro-FloII). But to how high a RPM? Remember that 30 degree/720 degree thing!

airfuelEddie wrote:Hey Drew, when you got your Demon carb did you Jet it for Denvers 5000+ feet above sea level elevation?

oh yea i have changed the jets i will let you know what i used and we can go from there yea the ultra thin air is a bitch, alot of people over look it may there brains suffer from lack of oxygen

drewcrane wrote:

airfuelEddie wrote:Hey Drew, when you got your Demon carb did you Jet it for Denvers 5000+ feet above sea level elevation?

oh yea i have changed the jets i will let you know what i used and we can go from there yea the ultra thin air is a bitch, alot of people over look it may there brains suffer from lack of oxygen

Then I better let Dave&Bob drive. Or take real deep breaths.

ok i did find 2 problems so far , for years since i have been driving this car since 1992 i have had a harmonic vibraton through out the drive train,

well i found the root of the problem it was the power steering pump pully/or shaft was bent it was the origonal unit when i bought the car it never leaked so i went with it, someone must have dropped it or something but it pumped so i could see it when running but never thought it was a problem until i replaced the whole unit and the pully and alot of the vibration is now gone,

what that type of vibration did was shake the crap out of vital components like the carb, and yesterday i noticed a leak in both the float bowls so after tightening the bowls it does run better but i still plan on removing the carb and checking all the parts and replacing the gaskets as well as the power valves,etc.i have been plagued with this vibration for a long time, in fact my first thread on this forum was about this problem ,so i am cautiously optomistic about this car ,but i want to check some other components for loose bolts ,etc.so i will post as soon as i know,

Great catch Drew! Your Power Valve should be all metal. I think Barry Grant carbs use them exclusively. At idle your vacum should be a certain amount. This number is divided in 1/2 and thats the Power valve number you should have. 12" of vacum at 800 RPM's would be a number 6 power valve. Dave can check to make sure thats right.

ok i have 11 inches of vacuum i used a 55 power valve and it stumbled,so after talking to 3 speed shops about it they asked if it was a street car and it is they said the 55 is great for drag racing but try an 85 pv and i did that and man it runs like a striped ass ape , i need more tire cause it wont hook up its like driving on ice it really made a difference i know from the demon instructional vid they said to divide the vac. number in half but it really stumbled alot so now with the 85 pv i know it goes against the rules of reason but 3 different speed shops cant be that wrong ,one guy runs a 440 in a super bee ,so for now it runs great i will have to drive it tomorrow in the heat and see what it does then again thanks guys you truly have been alot of help

The engine speaks a language all it's own. Glad to hear it Drew! I'm sure the elevation had something to do with it.

Lesson learned.

That is 5.5 inches and 8.5 inches of vacuum Drew.

First rule of carb tuning.
Once the timing and idle mixture are set (in gear on an auto) you must measure manifold vacuum (again in gear) and fit a power valve rated about 2 inches below your reading.

Here endith the lesson.

(again in gear) i will check that today good advice dave

I'm sure the elevation had something to do with it. it seems that most of the testing on alot of cars is done at sea level so compensation is needed to run in the rareified air

Drew did you keep the Jets the same number? How much timing do you have? Still want that fuel infection?

drewcrane wrote:(again in gear) i will check that today good advice dave

Actually one inch below the in gear vacuum would probably be better.

yea you were reading my mind its about 10.5 inches (in gear) im going to get a 7.5 inches and an 9.5 inches since i will have total 5.5 ,6.5,7.5,8.5 ,9.5 the guy said perhaps a 9.5 might work ,so will have a few to chose from at this point,ill let you know, im going there now

airfuelEddie wrote:Drew did you keep the Jets the same number? How much timing do you have? Still want that fuel infection?

right now i have the same jets and no infection,
i have an msd variable timing unit in the car so i do change that with the different fuel and, what runs the best advance with out pinging,up here we can run a little more advance timing and i have to really advance it before i get any ping ,i have light ill check that and see

drewcrane wrote:

airfuelEddie wrote:Drew did you keep the Jets the same number? How much timing do you have? Still want that fuel infection?

right now i have the same jets and no infection,
i have an msd variable timing unit in the car so i do change that with the different fuel and, what runs the best advance with out pinging,up here we can run a little more advance timing and i have to really advance it before i get any ping ,i have light ill check that and see

Cool ,thanks Drew, I want to possibly change some things on my set-up and want to know where your baseline is. My cam is 245/@.050 112 LSA, ..525 lift 8" of vacum at 800 RPM,,I think I remember your cam specs as close to mine.

with THE 1:5 rockers it was 0.538 lift/0.549 lift,duration is @.50 223/230 in not sure if i typed this right but now i have 1:6 rockers making it a little hotter than these numbers so your right they are about the same

ok after some test driving in about 85 degrees f air temp i still notice a stumble from a standing start, i did notice the accerlator pump was a little to tight,also here is the current set up with the fuel coming thru a fuel filter and then to the carb and then i have my regulator after the carb with the gauge after that it says about 6 1/2 lbs of fuel my question is that regulator in the right place? i had it before the carb and it didnt run as well as it does now i noticed on yours dave that the reg. is before the carb is that important?here is a pic, i also run a return line back to the tank,do you guys run a return line? also i am running 10 inches of vac. (in gear) with and 8.5 power valve,jets are 70,s in both primary and secondary