Fuel Pump Questions:
03-24-2011, 08:39 AM
#1
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Car: 1992 25 Anniversary Chevy Camaro RS
Engine: TBI 305sb
Transmission: 700R-4
Axle/Gears: Stock
Fuel Pump Questions:
I'm new to carburetors so I've been doing a lot of reading. But there are still a few things I'm in the dark about. I do NOT want to touch a carb until I understand just about everything about it.
I'm wanting to convert my 92 TBI to a carb engine so I can eliminate all of the computer related items under the hood. But also because I feel a true muscle car has a carburetor.
Now what I'm having confusion with is that I read with installing a carb on these cars we need to keep the fuel pressure between 4-8psi? And to do so we need to install a 3 port AFPR, or an electric in take fuel pump? The AFPR I can do no problem, but I hear that the safest way to go about this is the electronic fuel pump.
How does the electric fuel pump know how much pressure to deliver to the carb? Are there adjustments? Is there something else controlling it? I'm reading some of these FAQ's and stickies but maybe I'm just not understanding it still.
I know right now this is all over my head, but that's ok because at one point in time it was over everybody else head as well. So I'm learning about all of this and I hope asking the right questions.
Also if I were to install the electric fuel pump, is this the pump I would want to use?
http://www.summitracing.com/parts/VPN-GCA758-2/
I'm wanting to convert my 92 TBI to a carb engine so I can eliminate all of the computer related items under the hood. But also because I feel a true muscle car has a carburetor.
Now what I'm having confusion with is that I read with installing a carb on these cars we need to keep the fuel pressure between 4-8psi? And to do so we need to install a 3 port AFPR, or an electric in take fuel pump? The AFPR I can do no problem, but I hear that the safest way to go about this is the electronic fuel pump.
How does the electric fuel pump know how much pressure to deliver to the carb? Are there adjustments? Is there something else controlling it? I'm reading some of these FAQ's and stickies but maybe I'm just not understanding it still.
I know right now this is all over my head, but that's ok because at one point in time it was over everybody else head as well. So I'm learning about all of this and I hope asking the right questions.
Also if I were to install the electric fuel pump, is this the pump I would want to use?
http://www.summitracing.com/parts/VPN-GCA758-2/
03-24-2011, 11:17 AM
#2
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Car: 1992 RS
Engine: Carbed 350
Transmission: 700R4
Axle/Gears: 3.42 posi
Re: Fuel Pump Questions:
You already have an electric fuel pump in the tank, so you just use it.
And yes, you need a maximum of 6psi for a carb. Your fuel pump currently pumps about double that. So you use a Mallory 4309 fuel pressure regulator so that you can reduce the pressure down for the carb.
The Mallory is one (and the most popular) option - other brands available, but you have to use a RETURN-STYLE regulator - these take the excess fuel and return it to the tank, this returning fuel cools the fuel pump in the tank and keeps it happy.
The other kind of regulator is what's called a "dead-head" - it doesn't return fuel to the tank, it just stops it's flow. Bad for this - makes fuel pump run hot and dead-head regulators can't really reduce the pressure well enough. These type regulators are used when you only have like 7psi, and you need to reduce down to 5psi (small changes in psi). But since your TBI fuel pump is making 12+ psi, you need a return style regulator - the only way to effectively reduce the pressure is to "return" the unused fuel back to the tank. Make sense?
You also need to make sure it's legal for you to swap to carb - it's not in many states, and federally it's illegal everywhere (but feds dont enforce).
And, it's not a simple matter of swapping the carb in. You'll need:
Carb $250+
Intake $200+
Mallory 4309 $90
Vacuum Advanced Dist $125+
Throttle Cable Brackets $30+
Misc fittings, fuel line, etc. $30+
And since you have an automatic, you'll need:
Torque converter lockup $20 - $100+
TV Cable Geometry Corrector for carb $20
Your torque converter (TC) in your automatic tranny is computer controlled, no computer = no TC lockup. There's a sticky in carb section "TCC Lockup" that explains it all. Most folks install a kit to lock it, about $100, and the tranny pan has to be removed to install new solenoid/wiring into tranny. Some rig their own (see that sticky for wiring diags).
You have to have a new distributor since yours is currently computer controlled.
You have to have a new intake since yours is designed only for the TBI unit.
All the "+" after the costs I just put in because it depends on brands chosen, the costs I list are basic - not the "fancy" brand names.
And yes, you need a maximum of 6psi for a carb. Your fuel pump currently pumps about double that. So you use a Mallory 4309 fuel pressure regulator so that you can reduce the pressure down for the carb.
The Mallory is one (and the most popular) option - other brands available, but you have to use a RETURN-STYLE regulator - these take the excess fuel and return it to the tank, this returning fuel cools the fuel pump in the tank and keeps it happy.
The other kind of regulator is what's called a "dead-head" - it doesn't return fuel to the tank, it just stops it's flow. Bad for this - makes fuel pump run hot and dead-head regulators can't really reduce the pressure well enough. These type regulators are used when you only have like 7psi, and you need to reduce down to 5psi (small changes in psi). But since your TBI fuel pump is making 12+ psi, you need a return style regulator - the only way to effectively reduce the pressure is to "return" the unused fuel back to the tank. Make sense?
You also need to make sure it's legal for you to swap to carb - it's not in many states, and federally it's illegal everywhere (but feds dont enforce).
And, it's not a simple matter of swapping the carb in. You'll need:
Carb $250+
Intake $200+
Mallory 4309 $90
Vacuum Advanced Dist $125+
Throttle Cable Brackets $30+
Misc fittings, fuel line, etc. $30+
And since you have an automatic, you'll need:
Torque converter lockup $20 - $100+
TV Cable Geometry Corrector for carb $20
Your torque converter (TC) in your automatic tranny is computer controlled, no computer = no TC lockup. There's a sticky in carb section "TCC Lockup" that explains it all. Most folks install a kit to lock it, about $100, and the tranny pan has to be removed to install new solenoid/wiring into tranny. Some rig their own (see that sticky for wiring diags).
You have to have a new distributor since yours is currently computer controlled.
You have to have a new intake since yours is designed only for the TBI unit.
All the "+" after the costs I just put in because it depends on brands chosen, the costs I list are basic - not the "fancy" brand names.
03-24-2011, 12:18 PM
#3
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Car: 1992 25 Anniversary Chevy Camaro RS
Engine: TBI 305sb
Transmission: 700R-4
Axle/Gears: Stock
Re: Fuel Pump Questions:
You already have an electric fuel pump in the tank, so you just use it.
And yes, you need a maximum of 6psi for a carb. Your fuel pump currently pumps about double that. So you use a Mallory 4309 fuel pressure regulator so that you can reduce the pressure down for the carb.
The Mallory is one (and the most popular) option - other brands available, but you have to use a RETURN-STYLE regulator - these take the excess fuel and return it to the tank, this returning fuel cools the fuel pump in the tank and keeps it happy.
The other kind of regulator is what's called a "dead-head" - it doesn't return fuel to the tank, it just stops it's flow. Bad for this - makes fuel pump run hot and dead-head regulators can't really reduce the pressure well enough. These type regulators are used when you only have like 7psi, and you need to reduce down to 5psi (small changes in psi). But since your TBI fuel pump is making 12+ psi, you need a return style regulator - the only way to effectively reduce the pressure is to "return" the unused fuel back to the tank. Make sense?
You also need to make sure it's legal for you to swap to carb - it's not in many states, and federally it's illegal everywhere (but feds dont enforce).
And, it's not a simple matter of swapping the carb in. You'll need:
Carb $250+
Intake $200+
Mallory 4309 $90
Vacuum Advanced Dist $125+
Throttle Cable Brackets $30+
Misc fittings, fuel line, etc. $30+
And since you have an automatic, you'll need:
Torque converter lockup $20 - $100+
TV Cable Geometry Corrector for carb $20
Your torque converter (TC) in your automatic tranny is computer controlled, no computer = no TC lockup. There's a sticky in carb section "TCC Lockup" that explains it all. Most folks install a kit to lock it, about $100, and the tranny pan has to be removed to install new solenoid/wiring into tranny. Some rig their own (see that sticky for wiring diags).
You have to have a new distributor since yours is currently computer controlled.
You have to have a new intake since yours is designed only for the TBI unit.
All the "+" after the costs I just put in because it depends on brands chosen, the costs I list are basic - not the "fancy" brand names.
And yes, you need a maximum of 6psi for a carb. Your fuel pump currently pumps about double that. So you use a Mallory 4309 fuel pressure regulator so that you can reduce the pressure down for the carb.
The Mallory is one (and the most popular) option - other brands available, but you have to use a RETURN-STYLE regulator - these take the excess fuel and return it to the tank, this returning fuel cools the fuel pump in the tank and keeps it happy.
The other kind of regulator is what's called a "dead-head" - it doesn't return fuel to the tank, it just stops it's flow. Bad for this - makes fuel pump run hot and dead-head regulators can't really reduce the pressure well enough. These type regulators are used when you only have like 7psi, and you need to reduce down to 5psi (small changes in psi). But since your TBI fuel pump is making 12+ psi, you need a return style regulator - the only way to effectively reduce the pressure is to "return" the unused fuel back to the tank. Make sense?
You also need to make sure it's legal for you to swap to carb - it's not in many states, and federally it's illegal everywhere (but feds dont enforce).
And, it's not a simple matter of swapping the carb in. You'll need:
Carb $250+
Intake $200+
Mallory 4309 $90
Vacuum Advanced Dist $125+
Throttle Cable Brackets $30+
Misc fittings, fuel line, etc. $30+
And since you have an automatic, you'll need:
Torque converter lockup $20 - $100+
TV Cable Geometry Corrector for carb $20
Your torque converter (TC) in your automatic tranny is computer controlled, no computer = no TC lockup. There's a sticky in carb section "TCC Lockup" that explains it all. Most folks install a kit to lock it, about $100, and the tranny pan has to be removed to install new solenoid/wiring into tranny. Some rig their own (see that sticky for wiring diags).
You have to have a new distributor since yours is currently computer controlled.
You have to have a new intake since yours is designed only for the TBI unit.
All the "+" after the costs I just put in because it depends on brands chosen, the costs I list are basic - not the "fancy" brand names.
I figured we already had electronic fuel pumps in our cars, I always listen for mine to come on and prime the system before I start the car. So that cleared up one of my questions. And thanks for referencing the AFPR, I'm sure I can find that on Summit. Thanks for all the info and help!
03-24-2011, 01:03 PM
#4
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Car: 1992 RS
Engine: Carbed 350
Transmission: 700R4
Axle/Gears: 3.42 posi
Re: Fuel Pump Questions:
When you get to that point, you'll need fuel injection hose - it's about $3 a foot - NOT carb hose which is only $1 a foot - it'll state Fuel Injection on the side.
You'll need 5/16 hose and 3/8 hose. 3/8 is your feed line, 5/16 is your return. You'll also need hose barbs in both 3/8 and 5/16 - don't try to shove a 3/8 hose barb into the 5/16 hose - it'll cut the inner wall of the hose, leaving a flap of rubber inthere that will cause a restriction, and this restriction in the return line will make the fuel pressure too high (ask me how I know this
).
You can get the hose barbs, and metric to standard fittings in brass at the local hardware store - in the plumbing section. The factory metal lines have metric threads, but the hose barbs are all NPT threads, but hardware store will have conectors to make it work. The Mallory unit uses NPT threads, so no issue there.
Make sure to get a "banjo" fitting for your carb - helps alot when tryng to fit a filter on it.
On the Mallory 4309, the return line gets connected to the bottom, your feed line in and feed line out connect anywhere on the sides.
Good Luck! Let us know how it goes!
You'll need 5/16 hose and 3/8 hose. 3/8 is your feed line, 5/16 is your return. You'll also need hose barbs in both 3/8 and 5/16 - don't try to shove a 3/8 hose barb into the 5/16 hose - it'll cut the inner wall of the hose, leaving a flap of rubber inthere that will cause a restriction, and this restriction in the return line will make the fuel pressure too high (ask me how I know this
).You can get the hose barbs, and metric to standard fittings in brass at the local hardware store - in the plumbing section. The factory metal lines have metric threads, but the hose barbs are all NPT threads, but hardware store will have conectors to make it work. The Mallory unit uses NPT threads, so no issue there.
Make sure to get a "banjo" fitting for your carb - helps alot when tryng to fit a filter on it.
On the Mallory 4309, the return line gets connected to the bottom, your feed line in and feed line out connect anywhere on the sides.
Good Luck! Let us know how it goes!
03-24-2011, 01:35 PM
#5
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Car: 1992 25 Anniversary Chevy Camaro RS
Engine: TBI 305sb
Transmission: 700R-4
Axle/Gears: Stock
Re: Fuel Pump Questions:
I've said it once, and I'll say it again. Out of all the car tech forums I've ever been a member on, this is by far the best. Everybody is so nice and willing to help the new guys.
Thank you for all of your help, this is making me feel more confident that I can get this done all on my own. Going from fuel injected Honda four cylinders to carbureted Chevy v8 is a complete 180...
Thank you for all of your help, this is making me feel more confident that I can get this done all on my own. Going from fuel injected Honda four cylinders to carbureted Chevy v8 is a complete 180...
03-24-2011, 01:43 PM
#6
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Car: 1992 RS
Engine: Carbed 350
Transmission: 700R4
Axle/Gears: 3.42 posi
Re: Fuel Pump Questions:
Well, the 305 even carbed might not be faster than the Honda was, but the car is definitely "cooler' looking in my opinion. But don't despair on the speed, there's alot more you can do later - like a 350 swap.
I enjoyed my 305 car alot before I did the 350 swap, and now I enjoy it even more - although it's not that often that I really get my foot into it. It's fun when I feel the need, but mostly I just cruise with the tops out and enjoy the ride. So enjoy the car no matter how fast/slow it is!
And always feel free to PM me if you need, I'm happy to help!
I enjoyed my 305 car alot before I did the 350 swap, and now I enjoy it even more - although it's not that often that I really get my foot into it. It's fun when I feel the need, but mostly I just cruise with the tops out and enjoy the ride. So enjoy the car no matter how fast/slow it is!
And always feel free to PM me if you need, I'm happy to help!
03-24-2011, 02:00 PM
#7
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Join Date: Mar 2011
Location: Springfield, MO
Posts: 177
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Car: 1992 25 Anniversary Chevy Camaro RS
Engine: TBI 305sb
Transmission: 700R-4
Axle/Gears: Stock
Re: Fuel Pump Questions:
Well, the 305 even carbed might not be faster than the Honda was, but the car is definitely "cooler' looking in my opinion. But don't despair on the speed, there's alot more you can do later - like a 350 swap.
I enjoyed my 305 car alot before I did the 350 swap, and now I enjoy it even more - although it's not that often that I really get my foot into it. It's fun when I feel the need, but mostly I just cruise with the tops out and enjoy the ride. So enjoy the car no matter how fast/slow it is!
And always feel free to PM me if you need, I'm happy to help!
I enjoyed my 305 car alot before I did the 350 swap, and now I enjoy it even more - although it's not that often that I really get my foot into it. It's fun when I feel the need, but mostly I just cruise with the tops out and enjoy the ride. So enjoy the car no matter how fast/slow it is!
And always feel free to PM me if you need, I'm happy to help!
The reason for all of the carb questions is because I have a 4 bold main rear, 1 piece seal 350sb sitting in my garage. And I have a pretty decent build list made up for a rebuild. Also, I'm debating on if I want to stick with my 700R-4 or go with a TH350... Time will tell, and it also will help my decision if I can even find a TH350 around here for a decent price or not.
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03-26-2011, 04:37 AM
#8
Re: Fuel Pump Questions:
It's for sure my Honda "was" faster than my Camaro. But the Honda had about 4 years worth of upgrades and motor swaps haha.
The reason for all of the carb questions is because I have a 4 bold main rear, 1 piece seal 350sb sitting in my garage. And I have a pretty decent build list made up for a rebuild. Also, I'm debating on if I want to stick with my 700R-4 or go with a TH350... Time will tell, and it also will help my decision if I can even find a TH350 around here for a decent price or not.
The reason for all of the carb questions is because I have a 4 bold main rear, 1 piece seal 350sb sitting in my garage. And I have a pretty decent build list made up for a rebuild. Also, I'm debating on if I want to stick with my 700R-4 or go with a TH350... Time will tell, and it also will help my decision if I can even find a TH350 around here for a decent price or not.
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