I have tried a different billet bowl that came on the carbs. Not APD carbs and same issue but haven’t tried stock bowls. It has been suggested and brought up that those bowls have had issues in the past but haven’t tried it yet. I have regulators that I can split and add one to each carb as Dave suggested so I’m going to try that next week and see if that fixes it.
Posts: 235 | Location: Tennessee | Registered: December 18, 2006
so what is the goal here because it can't be to win bracket races.
You've been fucing with carbs from multiple builders and MFI for 4 years, have had flooding issues for 4 years with numerous carbs, spentover $10k on terminators, carbs, sheet metal manifold, fuel pumps, regulators, carb bowls, floats, Rupert going through brand new APD carbs, pulling the engine for a "a flow guy" to set it up and still have issues yet don't want to run gas and be done with this once and for all.
So again, why do you continue to go down this road especially with a car that only runs low 6s in the 1/8th other than because you chose to?
Posts: 13522 | Location: NJ | Registered: August 20, 2000
JMO 38 lbs. is too much pressure for the regulator to handle. 25 lbs. is plenty of pressure out of the pump, especially with a front mounted fuel cell. I personally have never ran more than 25 lbs. at the pump, even with a rear mounted fuel cell. I normally set the regulator to 7 lbs. at 2000 rpms with a dead head regulator. With a return regulator, I would run 2.5 -3 lbs. at idle and no more than 8 at wide open. Any more pressure than that and it can blow past the needle and seat at wide open throttle, with either a stainless or titanium needle and seat. Pressure should not be an issue with a front mounted fuel cell, you do not have to fight G forces or the long fuel lines of a rear mounted fuel cell. Again just my opinion.
Get away from any regulator between the pump and carb. Use bypass regulator AFTER the carb(s). Otherwise, the regulator is a restriction. Deadhead regulator will likely be problematic with alcohol. Rear mounted cell makes everything harder.
For comparison, I'm running a front cell, -8 PTFE braided, Holley black pump, bypass reg after the carb, 100 micron screen after the carb, bronze screen still in Holley pump. Loses about 1 psi (per RP) in the 1/8 at 650 hp, 6.30. It does work, but it's on the ragged edge.
It sounds like there is a float problem (is the spring on the float? Float heavy?) AND a volume problem.This message has been edited. Last edited by: Brktracer,
Matt Ward
Posts: 1389 | Location: South Carolina | Registered: March 20, 2004
Not knocking some of the replies here but you are all missing the problem on his end! There is no reason that a properly setup fuel system won't work on this combo. So ya, a dead head regulator will work, a bypass regulator will work etc, etc.
38 PSI out of the fuel pump is crazy! This combo will easily work with 21! Magnafuel has two relief valve springs for their big pumps to account for 12v vs 16v systems. When switch from 12 v to 16v, all the motors run faster so for fuel pumps its mean higher pressure out of the pumps! You do not want too high pressure being produce by the fuel pump.
Two carbs on alky are easier to feed the motor than one carb since the N&S's are the restriction which is why their dual N&S bowls being produced! But with his combo they are not required by a long shot.
The fact that he has a front mounted tank and had issues with a belt drive pump screams "there is an issue"!
Originally posted by C Hodge: -8 vent even tried a -10 vent Car is running when I set pressure and yes stainless N&S Car as done this all year with new carbs, and new bowls/float and another new set of floats I’ve had .130 in it and no change. I do agree I don’t need the .150s if the pressure was up a think I could get by with using .110 or .120s Tank is in the front with the belt pumps and the electric. I’ve tried 2 Holley small non liquid filled gauges, auto meter 2 1/6 gauge and my racepak sensor and all the gauges read the same with the racpak reading 3/4 pound lower. And no ED I’ll never swap back to gas. Been running alcohol carbs and injection for 25 years and no desire to change back to gas. Don’t get me wrong the car has been good all year running the low pressure with the exception of the air fuel going lean maybe 1 in 20 passes and I think turning the psi up from 32 to 38 on the pump will fix that issue but drives me crazy trying to figure out why it won’t run 4 to 6 psi. Maybe it’s something in the carbs and I’ll know that next week as I have 2 new APD 950s on the way to replace the 1050s that I have now
two 1050s or two 950s seems like an awful lot of cfm for a 780hp combo....
Posts: 549 | Location: somewhere between been and never was | Registered: November 03, 2002
Mr. Hodge about the only things different on our 2 combos is engine cubic inch and float bowls. Mine are stock Holley and I have 1400 CFM of carbs on a 358 so... not too much. If the regulators dont do it you might try the stock style float bowls-simple is always better!
The difference between ignorance and stupidity. Ignorance is lack of knowledge. Stupidity is the inability to learn. Don't be stupid
Posts: 406 | Location: des moines iowa | Registered: January 10, 2020
Ed a direct quote from my wife. I just live messing with ****. Does a 440 sbc need a tunnel ram and two carbs, a dry sump. Absolutely not. Any carb builder will tell you two carbs are more consistent. Same length runners and air/fuel has a straight shot plus most of the time adds a little power. I can promise you the issue I’m dealing with does not affect consistency unless I’ve been messing with something and is one of the most consistent cars at any track I go to.
Two 1050 is to big but my builder choice said that’s what I needed. When I talked to APD the first time they said 950s and said the same when I ordered these. I told them 750 or 850s would be fine if they thought it would be more consistent and they said 950s were the best choice.
I’ve had bypass regulators mounted in front and behind the carbs and both acted the same. I also agree 38psi pump pressure isn’t necessary if I could run over 3.5 at the carbs. At 30psi it runs out of fuel on launch because the carbs aren’t getting the 6.5 they need so the band-aid is more pump pressure until I figure out how to get that. Two regulators or different bowls will be tried at some point.
Posts: 235 | Location: Tennessee | Registered: December 18, 2006
The bowls need more vent. Then, you will be able to run a higher fuel pressure. To see if this is the issue, you will need to make a pass with a bowl screw out of each corner at the highest point of carb. Id suggest do the burn out, shut off, have helpers pull 1 screw, high side towards front of car of each carb, then make a pass and kill at end of track, if it gets better, figure out how to vent the bowls
Jeremiah Hall
Posts: 708 | Location: Evansville, IN | Registered: February 24, 2010
Originally posted by C Hodge: Ed a direct quote from my wife. I just live messing with ****. Does a 440 sbc need a tunnel ram and two carbs, a dry sump. Absolutely not. Any carb builder will tell you two carbs are more consistent. Same length runners and air/fuel has a straight shot plus most of the time adds a little power. I can promise you the issue I’m dealing with does not affect consistency unless I’ve been messing with something and is one of the most consistent cars at any track I go to.
Two 1050 is to big but my builder choice said that’s what I needed. When I talked to APD the first time they said 950s and said the same when I ordered these. I told them 750 or 850s would be fine if they thought it would be more consistent and they said 950s were the best choice.
I’ve had bypass regulators mounted in front and behind the carbs and both acted the same. I also agree 38psi pump pressure isn’t necessary if I could run over 3.5 at the carbs. At 30psi it runs out of fuel on launch because the carbs aren’t getting the 6.5 they need so the band-aid is more pump pressure until I figure out how to get that. Two regulators or different bowls will be tried at some point.
I will say this one last time, you have a problem that you haven't addressed. There is no way you need 30 PSI out of the pump nor is that pump pressure causing a lean condition at the launch! There is no reason you can't run 6 to 7 psi at the carbs. If you can't run 20 out of the pump and 6 to 7 at the carbs, figure out why, cuz you are the only one who can't!
Whatever you have been doing, it's just band aiding the real problem.
Originally posted by C Hodge: Any carb builder will tell you two carbs are more consistent.
1. I’ve had many conversations with the top carb builders in the country and not one has ever stated that. 2. Look around, The Who’s who of bracket racing all run one carb. 3. 2 carbs aren’t going to make a car that is already deadly consistent, more consistent. One good carb is all we need and is more than enough for engines making upwards of 1400HP.
Posts: 13522 | Location: NJ | Registered: August 20, 2000
my new car has a problem if anyone has any ideas. along the same lines as OP. it leaves fine but down track it lays over like it is starving for fuel then will pick up then lay over like no fuel. i have a magna fuel 500 pump as well front tank dead head regulator set at 7 psi. the only thing i have found is the factory bypass is the smaller outlet hole and stiff spring. i have run in to this on my camaro when i went to this pump on it. the pump pressure is probably above 30 psi. i drilled the bypass and cut the spring, run the bypass out as far as i could so now i am at around 18 to 20 psi at the pump. just with this change my regulator pressure went from 7 psi to 10.5 psi so i reset it back to 7. i have not run it since this change.
does anybody have any ideas as to what might be going on?
i tried a smaller carb before this and it was much worse. wouldnt run at all down track. on my camaro my regulator could not control the 30+ psi pump pressure. once i lowered the pump psi everything was good. wonder if something like tat is what i have going on.
Originally posted by pauley: my new car has a problem if anyone has any ideas. along the same lines as OP. it leaves fine but down track it lays over like it is starving for fuel then will pick up then lay over like no fuel. i have a magna fuel 500 pump as well front tank dead head regulator set at 7 psi. the only thing i have found is the factory bypass is the smaller outlet hole and stiff spring. i have run in to this on my camaro when i went to this pump on it. the pump pressure is probably above 30 psi. i drilled the bypass and cut the spring, run the bypass out as far as i could so now i am at around 18 to 20 psi at the pump. just with this change my regulator pressure went from 7 psi to 10.5 psi so i reset it back to 7. i have not run it since this change.
does anybody have any ideas as to what might be going on?
i tried a smaller carb before this and it was much worse. wouldnt run at all down track. on my camaro my regulator could not control the 30+ psi pump pressure. once i lowered the pump psi everything was good. wonder if something like tat is what i have going on.
ep-any help is appreciated
Have you checked the vent?
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Posts: 2944 | Location: KIEFER, OK. | Registered: August 17, 2007
