need a new carb
10-07-2002, 05:27 PM
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need a new carb
hey people......i just started my car up for the first time after putting in my 9" with ladderbars, roll cage, and world heads. the car ran fine with the edelbrock carb on it before. well now that i have heads with 200cc runners instead of 160cc double humps i am at the limit of my 750 edelbrock. i can't get it to richen up anymore with the jet kit i have for it. it is running ung0dly lean. some people have been recomending a demon 850, alot of people actually. all the specs of the motor are in my sig and i was just wanting some extra opinions. thanks.
10-07-2002, 05:44 PM
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Car: 1986 Iroc
Engine: 454 Demon 850DP
Transmission: TH350, 3500 stall
Axle/Gears: 3.73
I have the Speed Demon 850DP on my 406 and have been quite happy with it. Ran well right out of the box. Little or no adjustments needed in my case.
10-07-2002, 07:37 PM
#4
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The carb is not the problem.
your problem is fuel delivery (volume not pressure)
You can buy larger hi flow inlet needles and seats for
your carb.
But, either something is causing a restriction in the fuel line or your fuel pump is not able to pump enough fuel.
Give some info on your fuel system. May be able to suggest
a few thing to help.
your problem is fuel delivery (volume not pressure)
You can buy larger hi flow inlet needles and seats for
your carb.
But, either something is causing a restriction in the fuel line or your fuel pump is not able to pump enough fuel.
Give some info on your fuel system. May be able to suggest
a few thing to help.
Last edited by F-BIRD'88; 10-07-2002 at 07:43 PM.
10-07-2002, 10:04 PM
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my fuel system consists of a holly blue electric pump with regulator at 6.5psi and a fram racing canister fuel filter. running 1/2" fuel lines. i seriously doubt fuel delivery is the problem but i'll try anything before i buy a demon (WILL NOT buy a holley so don't even recomend one)
10-07-2002, 10:57 PM
#6
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I'm not a big fan of the holley blue pumps.
they are in a work JUNK. Never seen one that lasted long.
My friend recently put two brand new ones ( against my better advice) on his 700hp 10sec BBC Cutlass and all most roasted the motor from fuel starvation 'cause one of the pumps crapped out.
Total life : 5 minutes.
I could go on and on about those pumps, but I'll spare ya this time. Check the system for total flow to see if the pump is keeping up.
Put the carb on its side (say, throttle linkage down) in a big bucket while hooked up to your fuel line and turn the pump on.
So the carb fills up and spills over filling up the bucket.
Read your fuel pressure guage while doing this.
tip the carb around to get max fuel flow. this will simulate fuel flow during full throttle power.
If it won't maintain 3 to 4 psi while under full fuel flow and fill the bucket in time (GPH) than thats your problem.
the high flow needle and seat set is part#1466
they are .110" as opposed to .093"..... may help.
May have to increase the fuel pressure a little.
The regulator and or fuel filter could be clogged too.
Next time buy Two Carter electric pumps and run them in parrallel. they will out flow the holley and live forever.
Cost less too. They are the only hot rod type pump that was origionaly designed for continous use, that you and I can afford.
they'll even out live the ones we can't afford.
What do you think of the GM Z28 offroad cam your using?
How is the idle, drivability and vaccuum? When does the power come on? I was thinking it would make a good nitrous cam.
they are in a work JUNK. Never seen one that lasted long.
My friend recently put two brand new ones ( against my better advice) on his 700hp 10sec BBC Cutlass and all most roasted the motor from fuel starvation 'cause one of the pumps crapped out.
Total life : 5 minutes.
I could go on and on about those pumps, but I'll spare ya this time. Check the system for total flow to see if the pump is keeping up.
Put the carb on its side (say, throttle linkage down) in a big bucket while hooked up to your fuel line and turn the pump on.
So the carb fills up and spills over filling up the bucket.
Read your fuel pressure guage while doing this.
tip the carb around to get max fuel flow. this will simulate fuel flow during full throttle power.
If it won't maintain 3 to 4 psi while under full fuel flow and fill the bucket in time (GPH) than thats your problem.
the high flow needle and seat set is part#1466
they are .110" as opposed to .093"..... may help.
May have to increase the fuel pressure a little.
The regulator and or fuel filter could be clogged too.
Next time buy Two Carter electric pumps and run them in parrallel. they will out flow the holley and live forever.
Cost less too. They are the only hot rod type pump that was origionaly designed for continous use, that you and I can afford.
they'll even out live the ones we can't afford.
What do you think of the GM Z28 offroad cam your using?
How is the idle, drivability and vaccuum? When does the power come on? I was thinking it would make a good nitrous cam.
Last edited by F-BIRD'88; 10-07-2002 at 11:07 PM.
10-08-2002, 10:31 AM
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ok cool i'll have to try that. just doesn't seem like a problem with my fuel system though.
i love the cam. it actually idle's pretty well with a 112lsa. power comes on HARD at 4000rpm on up to about 7000 is as high as i've had it but it was still climbin when i let out of it. vacuum? this cam makes vacuum? lol not hardley. with my reserve canister my power brakes work just enough to get me stopped. i been thinking about switching to an after market manual set-up but i ain't sure yet. if'n i get my latest project finished up this week i'll have it down at the track next week to get a time with the 383 combo and my 9",ladder bar suspention set-up.
i love the cam. it actually idle's pretty well with a 112lsa. power comes on HARD at 4000rpm on up to about 7000 is as high as i've had it but it was still climbin when i let out of it. vacuum? this cam makes vacuum? lol not hardley. with my reserve canister my power brakes work just enough to get me stopped. i been thinking about switching to an after market manual set-up but i ain't sure yet. if'n i get my latest project finished up this week i'll have it down at the track next week to get a time with the 383 combo and my 9",ladder bar suspention set-up.
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10-08-2002, 08:34 PM
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Originally posted by F-BIRD'88
Put the carb on its side (say, throttle linkage down) in a big bucket while hooked up to your fuel line and turn the pump on.
So the carb fills up and spills over filling up the bucket.
Read your fuel pressure guage while doing this.
fuel pressure reads at 6.5psi.
tip the carb around to get max fuel flow. this will simulate fuel flow during full throttle power.
If it won't maintain 3 to 4 psi while under full fuel flow and fill the bucket in time (GPH) than thats your problem.
it maintained almost 5 psi and was filling a 5gallon bucket fairly fast.
the high flow needle and seat set is part#1466
they are .110" as opposed to .093"..... may help.
May have to increase the fuel pressure a little.
i may have to try the needle and seat. i double checked pressure before i started and it was at 6....reset it to 6.5psi cuz thats all they recomend you put on an edelbrock carb
Put the carb on its side (say, throttle linkage down) in a big bucket while hooked up to your fuel line and turn the pump on.
So the carb fills up and spills over filling up the bucket.
Read your fuel pressure guage while doing this.
fuel pressure reads at 6.5psi.
tip the carb around to get max fuel flow. this will simulate fuel flow during full throttle power.
If it won't maintain 3 to 4 psi while under full fuel flow and fill the bucket in time (GPH) than thats your problem.
it maintained almost 5 psi and was filling a 5gallon bucket fairly fast.
the high flow needle and seat set is part#1466
they are .110" as opposed to .093"..... may help.
May have to increase the fuel pressure a little.
i may have to try the needle and seat. i double checked pressure before i started and it was at 6....reset it to 6.5psi cuz thats all they recomend you put on an edelbrock carb
10-09-2002, 05:04 PM
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well all of the things you suggested provided only a small improvement. everyone i am talking to says "double pumper" at least an 800 and preferable a Demon. i'm gunna be in columbus on saturday so i am gunna stop by jegs and have a chat with some of the guys up there and hear what they have to say.
oh and thanks for all the replies......next time i see someone with simmilar problems with their edelbrock i'll have some new suggestions to offer them.
oh and thanks for all the replies......next time i see someone with simmilar problems with their edelbrock i'll have some new suggestions to offer them.
10-14-2002, 04:23 PM
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PROBLEM SOLVED!!!!!
well as much as i hate to say i switched to a holley, i did. slapped an 830cfm chokeless race carb on the beast. runs like a bat out of he||!!!!!!!!!! i do think i can see an 11 sec time slip on the way 
10-14-2002, 07:58 PM
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Car: 86 firebird with 98 firebird interi
Engine: pump gas 427sbc Dart Lil M 13.5:1
Transmission: Oldani TH400 w/ BTE 9" convertor
Axle/Gears: 31 spline Moser/full spool/4.11Rich
Good choice, I was running a Holley 750VS when everyone was telling me to run a DP, Bro-in-law had the same Holley 830 race carb you have, sittin on the shelf, so I swapped em out and picked up .3 and the car is MUCH more consistent now. Just about evryone at our track is buying the Holley 950HP and having GREAT results, even on slightly modified motors, average E.T. gain is .4 so the 830 race is pretty close.
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