performance fuel pump
02-09-03, 02:46 PM
#2
EliteHardcoreCannuckSquad
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Summit racing, any parts shop.
Most people install on the side of the frame rail. I had a friend of a friend at a shop drill the holes and mount the pump bracket for me, and I did the rest.
Search, lots of info on this!
Most people install on the side of the frame rail. I had a friend of a friend at a shop drill the holes and mount the pump bracket for me, and I did the rest.
Search, lots of info on this!
02-09-03, 04:23 PM
#3
1500 posts, knows nothing
.Check out www.summitracing.com or www.jegs.com. They have lots of fuel pumps, regualtors, gauges, etc. Make sure that you know what youre fuel requirements are so you dont go buying a huge pump when you dont need one
.~T.J.
02-09-03, 04:52 PM
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Re: performance fuel pump
Originally posted by Suparslinc
Where do I get a high pressure fuel pump and regulator?
How hard will they be to install?
Where do I get a high pressure fuel pump and regulator?
How hard will they be to install?
02-10-03, 08:04 AM
#7
Nikki-Modder Rex-Rodder
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Supraslinc-
Here's a copy of the letter to you. I'm sending the carb out tonight or tomorrow morning, UPS.
The mods are minor for now. Just the pump shot increase, the drilled primary jets, and the mechanical secondaries.
Mar3 strongly suggests the inexpensive Carter 7 psi pump and a Holley 4 PSI regulator.
"Joe-
I packed this carb up as best I could. I hope it finds you in perfect condition. I know it's a pain in the *** to have to deal with the expanding foam but it's great for packing.
I've installed an extra gasket in the accelerator pump which gives only a few drops extra, but it's enough to make a difference. I've also drilled out the primary jets to two sizes
larger. You'll notice a difference when you install a larger fuel pump. The better fuel pump is often noticeable even with stock jets. I redid the mechanical linkage as you had it. (Remember, the throttle body is from the other carb.)
I've included the old gaskets that I replaced, as well as the seats and needles. The new cotter pin for the OMP rod is attached to the vacuum advance linkage. The screens (there
are four) were clean, and the accelerator pump checkballs were fuctional. I found no excessive varnish throughout. All in all, aside of old gaskets it's a pretty clean carb. I did find however, that the throttle return spring mechanism was not hooked up correctly. This could well have hindered the carbs ability to fully function.
Installation:
Make certain that EVERYTHING is hooked up correctly. There can be NO vacuum leaks and the float bowl solenoid MUST be hooked up. The carburetor cannot breathe properly without the vent open to atmosphere, and it's only open when the solenoid is hooked up.
Be VERY CAREFUL when adjusting the cable so that when the pedal is pushed all the way down, you don't bend the primary throttle shaft. This is very easy to do, and once it is twisted one of the butterflies will never close properly, messing your idle up forever.
You'll very likely encounter a flooding of the float bowls. This usually happens with newly re-built carbs, and is a result (I think) of just new parts needing to rub together a bit to "break-in". The needle does'nt seat properly, or the springs hang up, and the float does not lift hard enough to push the needle valve closed. Gentle taps on top of where the inlet
bolts are on the top of the float bowls with a screwdriver handle will usually cure this. It may happen again. Soon enough, it will stop happening and you can get on with tuning, but probably not until you've flooded your engine at least once!
Idle cicuit:
The idle mixture screw is regulating the air/fuel mixture of the idle circuit. The idle circuit in the carb simply lets the ideling engine vacuum suck out a metered amount of fuel, and a metered amount of air. The fuel comes in from a jet pressed into the internals of the throttle body. It will only let so much fuel pass through it because it's so small- So you get to a point where no matter how much higher you go, that jet is already maxed out at maybe 2800 RPMs. You have no controll over the fuel except by raising the RPM of the idle.
The air comes from idle air bleeds on top of the carb body. What you are controlling with the mixture screw is the amount of air that is allowed to mix with the metered fuel. It's
simply a controlled vacuum leak. Raising the idle rpm can give more fuel, but only because there's more suction from the engine. More suction for the fuel also means more suction for
the "Leak" (mixture screw).
Getting it started:
Raising the idle speed beyond a certain point starts to run the main circuit. This is when the butterflies begin to open. The fuel mixture in the main circuit is dictated by fuel jet size and air bleed size, and those are not adjustable. The point here, is that you KNOW it will run on the main circuit no matter how out of tune the idle circuit is (aside of an all out leak). And the object is to keep the car running so you can tune it, cause you can't do squat if it's not running. And the more you try to start a rotary with a messed up carb, the more likey you are gonna flood it, not realize it, adjust things, try again and fail, and then readjust things again. You could have had it adjusted perfectly and not known it.
Now you're chasing your tail!
So this is what I've learned to do-
Turn the idle adjust screw in one and a half to two turns. This should substantially raise the idle of the engine. Now you're running the engine partially on the idle circuit, but mostly on the main circuit.
Once you've got it running, try to lower the idle no higher than 3k RPM. It's not good to have the engine rev too high when it's cold. Let it warm up to temperature. Adjusting idle while cold is a mistake. Fuel mixes differently when it's warmed from under the hood.
Once it's warm, reduce the idle to as far as you can, and then adjust the mixture screw. Go back and forth between reducing idle and adjusting mixture untill you can get the idle
down to 750 RPMs (Textbook ideal).
Troubleshooting:
First thing- Recheck everything. Flooded? Pull plugs and clean them off if they are dirty/wet. You want the ignition to be as
good as possible. But a flooded rotary can take an awful lot to clear its throat. Often waiting for a few minutes can make a big difference.
The float glasses are there for a reason. I've seen "problem" Rx-7s where the sight glasses were never cleaned to look through them. If the fuel level is higher than half way, it indicates a flooding problem. If they are are lower than half way, then your carb is'nt getting enough fuel. Flooding can be attributed to a few things. The float bowl solenoid not being hooked up is a definite. Sticking needles (cured with a tap on the top). No (or faulty) regulator with an aftermarket pump. The regulator is installed backwards. The return line is blocked. The checkvalve in the return line is installed backwards. The fuel tank breather line is plugged ("whooshing" when the cap is opened). These are all things that can cause the fuel level to be too high in the float bowls. But your carb can flood out by having blocked air bleeds, too. The air bleeds supply air to the emulsion tubes which then gets "bubbled" into the incoming fuel that sprays out the booster venturis. This is a "pre-mixing", and a very important part of achieving desired 'perfect' mixtures for
any given RPM or engine load. Usually this type of flooding just results in your engine running like crap with no power, but none the less running.
Not enough fuel in there? Blockage in the incoming line or inadequate pump supply is likely. The floats are heavy relative to the needles, and it's unlikely that new needles would stick
shut with four or five psi trying to blow them open. Usually it's a dirty fuel filter. Next is the fuel pump cut relay is malfunctioning. I'm assuming that they are wired so that in case of the relay burning out/ malfunctioning, fuel flow is
cut as a saftey precaution. Next is the fuel pump is tired. This is a likely thing, as they are of the piston design, and the piston and metal baffels are subject to abrasion from dirt entering. Minute rust particals, it's bound to happen.
Obviously there is the possibility that the float drop level was not set correctly by the rebuilder. This is usually not
something that needs to be adjusted.
Do not allow unfiltered fuel to enter the carb. All it takes is a tiny piece to become inbedded into the new soft rubber needle and it'll flood like crazy.
Do not put ATF or MMO down the throat of an untuned carb. This does NO GOOD at this point. For a death-bed engine, it may give better compression to help start it, but for a carb that's out of tune, you are simply adding another ingredient that changes the chemistry of the air-fuel mixture.
Others swear by it. I don't recommend it.
(Once the car is running, and the carb is all tuned, I DO recommend a "proper" ATF job, where
the engine is soaked in it for 48 hours, and then started to remove carbon deposits. I've done
it with great results.)
So there it all is.
Joe, I pray this starts right out of the box, and that you decide to keep your car afterall!
Cheers, Dennis.
PS- Of course, don't hesitate to Email me with questions and updates."
I'll have news about my plans for carb modification services in the future. Paul Yaw seems to have lost interest, and there's obviously a void to fill in this department.
I seriously doubt I'll ever be able to dedicate myself to the degree of knoweledgability that he has, but I'll do what I know I can for people.
Here's a copy of the letter to you. I'm sending the carb out tonight or tomorrow morning, UPS.
The mods are minor for now. Just the pump shot increase, the drilled primary jets, and the mechanical secondaries.
Mar3 strongly suggests the inexpensive Carter 7 psi pump and a Holley 4 PSI regulator.
"Joe-
I packed this carb up as best I could. I hope it finds you in perfect condition. I know it's a pain in the *** to have to deal with the expanding foam but it's great for packing.
I've installed an extra gasket in the accelerator pump which gives only a few drops extra, but it's enough to make a difference. I've also drilled out the primary jets to two sizes
larger. You'll notice a difference when you install a larger fuel pump. The better fuel pump is often noticeable even with stock jets. I redid the mechanical linkage as you had it. (Remember, the throttle body is from the other carb.)
I've included the old gaskets that I replaced, as well as the seats and needles. The new cotter pin for the OMP rod is attached to the vacuum advance linkage. The screens (there
are four) were clean, and the accelerator pump checkballs were fuctional. I found no excessive varnish throughout. All in all, aside of old gaskets it's a pretty clean carb. I did find however, that the throttle return spring mechanism was not hooked up correctly. This could well have hindered the carbs ability to fully function.
Installation:
Make certain that EVERYTHING is hooked up correctly. There can be NO vacuum leaks and the float bowl solenoid MUST be hooked up. The carburetor cannot breathe properly without the vent open to atmosphere, and it's only open when the solenoid is hooked up.
Be VERY CAREFUL when adjusting the cable so that when the pedal is pushed all the way down, you don't bend the primary throttle shaft. This is very easy to do, and once it is twisted one of the butterflies will never close properly, messing your idle up forever.
You'll very likely encounter a flooding of the float bowls. This usually happens with newly re-built carbs, and is a result (I think) of just new parts needing to rub together a bit to "break-in". The needle does'nt seat properly, or the springs hang up, and the float does not lift hard enough to push the needle valve closed. Gentle taps on top of where the inlet
bolts are on the top of the float bowls with a screwdriver handle will usually cure this. It may happen again. Soon enough, it will stop happening and you can get on with tuning, but probably not until you've flooded your engine at least once!
Idle cicuit:
The idle mixture screw is regulating the air/fuel mixture of the idle circuit. The idle circuit in the carb simply lets the ideling engine vacuum suck out a metered amount of fuel, and a metered amount of air. The fuel comes in from a jet pressed into the internals of the throttle body. It will only let so much fuel pass through it because it's so small- So you get to a point where no matter how much higher you go, that jet is already maxed out at maybe 2800 RPMs. You have no controll over the fuel except by raising the RPM of the idle.
The air comes from idle air bleeds on top of the carb body. What you are controlling with the mixture screw is the amount of air that is allowed to mix with the metered fuel. It's
simply a controlled vacuum leak. Raising the idle rpm can give more fuel, but only because there's more suction from the engine. More suction for the fuel also means more suction for
the "Leak" (mixture screw).
Getting it started:
Raising the idle speed beyond a certain point starts to run the main circuit. This is when the butterflies begin to open. The fuel mixture in the main circuit is dictated by fuel jet size and air bleed size, and those are not adjustable. The point here, is that you KNOW it will run on the main circuit no matter how out of tune the idle circuit is (aside of an all out leak). And the object is to keep the car running so you can tune it, cause you can't do squat if it's not running. And the more you try to start a rotary with a messed up carb, the more likey you are gonna flood it, not realize it, adjust things, try again and fail, and then readjust things again. You could have had it adjusted perfectly and not known it.
Now you're chasing your tail!
So this is what I've learned to do-
Turn the idle adjust screw in one and a half to two turns. This should substantially raise the idle of the engine. Now you're running the engine partially on the idle circuit, but mostly on the main circuit.
Once you've got it running, try to lower the idle no higher than 3k RPM. It's not good to have the engine rev too high when it's cold. Let it warm up to temperature. Adjusting idle while cold is a mistake. Fuel mixes differently when it's warmed from under the hood.
Once it's warm, reduce the idle to as far as you can, and then adjust the mixture screw. Go back and forth between reducing idle and adjusting mixture untill you can get the idle
down to 750 RPMs (Textbook ideal).
Troubleshooting:
First thing- Recheck everything. Flooded? Pull plugs and clean them off if they are dirty/wet. You want the ignition to be as
good as possible. But a flooded rotary can take an awful lot to clear its throat. Often waiting for a few minutes can make a big difference.
The float glasses are there for a reason. I've seen "problem" Rx-7s where the sight glasses were never cleaned to look through them. If the fuel level is higher than half way, it indicates a flooding problem. If they are are lower than half way, then your carb is'nt getting enough fuel. Flooding can be attributed to a few things. The float bowl solenoid not being hooked up is a definite. Sticking needles (cured with a tap on the top). No (or faulty) regulator with an aftermarket pump. The regulator is installed backwards. The return line is blocked. The checkvalve in the return line is installed backwards. The fuel tank breather line is plugged ("whooshing" when the cap is opened). These are all things that can cause the fuel level to be too high in the float bowls. But your carb can flood out by having blocked air bleeds, too. The air bleeds supply air to the emulsion tubes which then gets "bubbled" into the incoming fuel that sprays out the booster venturis. This is a "pre-mixing", and a very important part of achieving desired 'perfect' mixtures for
any given RPM or engine load. Usually this type of flooding just results in your engine running like crap with no power, but none the less running.
Not enough fuel in there? Blockage in the incoming line or inadequate pump supply is likely. The floats are heavy relative to the needles, and it's unlikely that new needles would stick
shut with four or five psi trying to blow them open. Usually it's a dirty fuel filter. Next is the fuel pump cut relay is malfunctioning. I'm assuming that they are wired so that in case of the relay burning out/ malfunctioning, fuel flow is
cut as a saftey precaution. Next is the fuel pump is tired. This is a likely thing, as they are of the piston design, and the piston and metal baffels are subject to abrasion from dirt entering. Minute rust particals, it's bound to happen.
Obviously there is the possibility that the float drop level was not set correctly by the rebuilder. This is usually not
something that needs to be adjusted.
Do not allow unfiltered fuel to enter the carb. All it takes is a tiny piece to become inbedded into the new soft rubber needle and it'll flood like crazy.
Do not put ATF or MMO down the throat of an untuned carb. This does NO GOOD at this point. For a death-bed engine, it may give better compression to help start it, but for a carb that's out of tune, you are simply adding another ingredient that changes the chemistry of the air-fuel mixture.
Others swear by it. I don't recommend it.
(Once the car is running, and the carb is all tuned, I DO recommend a "proper" ATF job, where
the engine is soaked in it for 48 hours, and then started to remove carbon deposits. I've done
it with great results.)
So there it all is.
Joe, I pray this starts right out of the box, and that you decide to keep your car afterall!
Cheers, Dennis.
PS- Of course, don't hesitate to Email me with questions and updates."
I'll have news about my plans for carb modification services in the future. Paul Yaw seems to have lost interest, and there's obviously a void to fill in this department.
I seriously doubt I'll ever be able to dedicate myself to the degree of knoweledgability that he has, but I'll do what I know I can for people.
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02-10-03, 05:40 PM
#8
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i have a highpressure pump that i am willing to sell, it is almost new, no regulator though, let me know, my email is jlozada@cfl.rr.com , later
jonathan
jonathan
02-10-03, 07:47 PM
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Originally posted by Sterling
[B]Mar3 strongly suggests the inexpensive Carter 7 psi pump and a Holley 4 PSI regulator.
/B]
[B]Mar3 strongly suggests the inexpensive Carter 7 psi pump and a Holley 4 PSI regulator.
/B]
02-10-03, 09:12 PM
#12
Nikki-Modder Rex-Rodder
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It's what I have. For winter tuning, I'm running hi pressure (five psi) through my modded Nikki. But I'm running huge jets and am excepting my 13 MPG. I have no fluxuation at all on the gauge. This tells me that the volume is heavy, and nice and consistant.
The Carter is a noisey *** pump, but dependable. It's a power-sucker-upper, though. Heavier gauge wires are very much suggested.
Mar3 hates the Carter pumps! He likes the Mollary. I just bust his *** about it. But for the money, the Carter's great.
The Carter is a noisey *** pump, but dependable. It's a power-sucker-upper, though. Heavier gauge wires are very much suggested.
Mar3 hates the Carter pumps! He likes the Mollary. I just bust his *** about it. But for the money, the Carter's great.
02-10-03, 09:43 PM
#13
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I went to www.summitracing.com and here is what I came up with; just to check are these the components sterling recommended?
CRT-P4594 Carter Electric Fuel Pumps $57.95 $57.95
HLY-12-804 Holley Fuel Pressure Regulator $23.95 $23.95
CRT-P4594 Carter Electric Fuel Pumps $57.95 $57.95
HLY-12-804 Holley Fuel Pressure Regulator $23.95 $23.95
02-10-03, 10:36 PM
#15
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Originally posted by Sterling
Mar3 strongly suggests the inexpensive Carter 7 psi pump and a Holley 4 PSI regulator.
Mar3 strongly suggests the inexpensive Carter 7 psi pump and a Holley 4 PSI regulator.
Originally posted by 85RX7GS
I'm planning on trying this configuration out on my stock port. Should be awesome!
I'm planning on trying this configuration out on my stock port. Should be awesome!
...all that misery can be avoided by using your tax refund to buy the 21st century gerotor-style Mallory Comp70 and you won't even need a regulator. When you step up to a streetport, you'll be able to sell it at 75% of what you paid for it and step up with the big dawgs to a Mallory Comp110 or Comp140 or even Aeromotive if you gots $$$ burning a hole in yer pocket...
02-10-03, 10:43 PM
#17
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And how the hell do you get to 1500 posts or 784 posts, whatever, and still have the stock fuel pump onboard??
That's like one of the first things that have to go as soon as you stick a cold air setup or pop some headers on....crazy...
That's like one of the first things that have to go as soon as you stick a cold air setup or pop some headers on....crazy...
02-10-03, 10:48 PM
#18
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Originally posted by TheTwinTurboRX-7
blah, I'll run my stereo loud enough to go deaf and deal with my pump.
blah, I'll run my stereo loud enough to go deaf and deal with my pump.
02-10-03, 11:06 PM
#20
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well I don't have a stereo nor do I need one at the time. I'm going ***** to the walls performance, still think the Carter is a poor choice?
How much wiring is required here? Are we talking all the way up to the fuse box? I had a fuel pump cut-off switch at one time and that was pretty simple.
How much wiring is required here? Are we talking all the way up to the fuse box? I had a fuel pump cut-off switch at one time and that was pretty simple.
02-10-03, 11:19 PM
#21
Nikki-Modder Rex-Rodder
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I presently have mine simply wired with the existing two pump (stock) wires. It's just that, like alot of others' I've read about, the pump pulsates when the blinkers are on - indicating it needs to have better wires.
The hard part is bolting it to the framework under the car. You should get a few feet of fuel hose, and position the pump where you can. There's limited places for it. Though other people have them screwed to the bottom of the compartment floors at 45* with no problem, Carter recomends the pump be installed straight up and down. (Shut up, Mario!
)
The hard part is bolting it to the framework under the car. You should get a few feet of fuel hose, and position the pump where you can. There's limited places for it. Though other people have them screwed to the bottom of the compartment floors at 45* with no problem, Carter recomends the pump be installed straight up and down. (Shut up, Mario!
)
02-10-03, 11:20 PM
#22
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Have you actually ever heard a Carter mar? 
Once my engine's running I can't even hear the ****** and my exhaust isn't that loud either. Or maybe I'm just deaf. lol
As for the wiring upgrade, the best way to do it IMO is to run a new wire from the battery and use the stock wires to power a relay. Any regular 30 or 40 amp automotive relay will do the trick. My voltage at the pump went from as low as 10v with the blinkers on to a solid 13v all the time.
Once my engine's running I can't even hear the ****** and my exhaust isn't that loud either. Or maybe I'm just deaf. lolAs for the wiring upgrade, the best way to do it IMO is to run a new wire from the battery and use the stock wires to power a relay. Any regular 30 or 40 amp automotive relay will do the trick. My voltage at the pump went from as low as 10v with the blinkers on to a solid 13v all the time.
02-10-03, 11:39 PM
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I can hear my carter at idle over the exhaust, not at anything higher than that, and I am not going overboard on stereo but I make long trips, need radio.
02-11-03, 12:25 AM
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Originally posted by REVHED
Have you actually ever heard a Carter mar? Once my engine's running I can't even hear the ****** and my exhaust isn't that loud either. Or maybe I'm just deaf. lol
As for the wiring upgrade, the best way to do it IMO is to run a new wire from the battery and use the stock wires to power a relay. Any regular 30 or 40 amp automotive relay will do the trick. My voltage at the pump went from as low as 10v with the blinkers on to a solid 13v all the time.
Have you actually ever heard a Carter mar?
Once my engine's running I can't even hear the ****** and my exhaust isn't that loud either. Or maybe I'm just deaf. lolAs for the wiring upgrade, the best way to do it IMO is to run a new wire from the battery and use the stock wires to power a relay. Any regular 30 or 40 amp automotive relay will do the trick. My voltage at the pump went from as low as 10v with the blinkers on to a solid 13v all the time.
...if you've got "headers", your car is loud....it's that relative thing again...an open header on a V8 doesn't hold a candle to the open exhaust of a rotary...I like your idea regarding the proper wiring for a big fuel pump out back. UltiRex will be done that way...
02-11-03, 07:13 PM
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Where's a good place to get the fittings to do the Carter pump/Holley regulator?
A guy I talked to at Summit recommended I replace the fuel line from the pump to the regulator with AN type fittings and hose because the pressure from the pump would cause clamped hoses to leak. Anybody had this problem?
Also, do you need to use both outlet ports on the regulator? It looks like there are two fuel inlets to the stock carb. I was planning to use one port to mount the pressure guage.
Thanks
A guy I talked to at Summit recommended I replace the fuel line from the pump to the regulator with AN type fittings and hose because the pressure from the pump would cause clamped hoses to leak. Anybody had this problem?
Also, do you need to use both outlet ports on the regulator? It looks like there are two fuel inlets to the stock carb. I was planning to use one port to mount the pressure guage.
Thanks