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Topic Review (Newest First)
11-12-2010 12:28 AM
NWayne I'm running a RobbMc fuel pump with a small roots blower. I got the one rated up to 1100hp. They're a little price but well worth it. Probably the last pump you'll ever buy.
11-11-2010 05:52 PM
techinspector1 Sometimes I think we lose sight of reality when sizing some of these components. Let's look at basics. Engineers will tell us that most engines will use 1/2 lb. of fuel per hour for each horsepower they produce. So, if you are making....say....525 horsepower, then multiplying 525 times .5 tells us that the motor will use 262.5 lbs. of fuel at full bore, pedal to the metal top speed. Since we know that gasoline weighs about 6 lbs. per gallon, we can divide 262.5 by 6 and find that the motor will be using 43.75 gallons per hour. Now, this is at full bore, wide open. How long will you run the motor like this? Probably not more than a few seconds. But we'll use the wide open figures to size the pump anyway. Just to be on the safe side though, we will double the fuel requirement and say that this particular motor needs 87.5 gallons per hour (43.75 times 2). That is the max volume of fuel needed to operate the motor at its full rating of 525 horsepower forever.

Realizing that we do not need a pump that will pump more than 87.5 gallons per hour to operate our world beater, we would look at a pump that would deliver that volume of fuel and do it at a pressure that would not overpower the needle and seat in the float bowl. A Holley carburetor will tolerate 6 1/2 lbs. of fuel pressure, but will operate well with a safety margin at 5 1/2 to 6 1/2 psi. Here is the pump for your motor. It is all you need....If you can show me math that says differently, I will gladly listen....

These other fellows are correct about configuring the nitrous system. Consider the carburetor as one complete system. Consider the nitrous as another complete system and plumb accordingly.

P.S. Use -8 lines (1/2 inch) everywhere.
11-11-2010 04:42 PM
ericnova72 Yes, a complete seperate line and pump for the nitrous, from the tank to the solenoid.
11-11-2010 07:37 AM
obengston When you say to add a second line for the nitrous. Does that run from the tank to the carb or does it tie in some where. I do have a 6-an braided line that has a electric pump and a regulator with it, that was from another vehicle.
11-11-2010 07:16 AM
ericnova72 I have had no problems with the Carters in the past.

If you are going to turn any rpm over 6500 or so make sure you get a lightweight fuel pump pushrod also so that you don't have problems with pump arm float, ARP has a nice one.

You will be asking a lot of a mechanical pump if you use nitrous and keep the stock 3/8" line size. Smarter move would be to add a second line and an electric pump for the nitrous, it does not like pulsed flow, steady flow is much better. Carter makes a nice quiet electric that would work well for this, and you would only have it on when you are going to be using the nitrous.
11-11-2010 07:01 AM
Irelands child
Originally Posted by obengston
Also with the hard lines I have now...How do I determine what size they are. I just measured with a digital scale it was 0.387, so what is that equal to??? Is that 6-an or 8.

That's a 3/8 or -6 in AN size. To and from the filter are the -6 lines:

(I wasn't done with the filter bracket in that photo as there is only one of 2 clamps shown)
11-11-2010 06:37 AM
obengston Also with the hard lines I have now...How do I determine what size they are. I just measured with a digital scale it was 0.387, so what is that equal to??? Is that 6-an or 8.
11-10-2010 02:29 PM
obengston SOunds good so far really thinking about the 170 GPH mechanical I showed.. needs no regulator but puts out really good. I plan on adding some nos in the future
11-10-2010 10:29 AM
Irelands child I have the Ford version of this one - Carter. Have always used one with good luck.
11-10-2010 09:11 AM
302 Z28 I have the high volume Edebrock mech pump. I have mixed reviews of it to date. It was on my engine for about two years and failed causing me to call a rollback wrecker to haul it home. Luckily when I purchased it I also purchased an overhaul kit. Once home I pulled the pump and installed the overhaul kit. So far it has been working fine, but if it fails again I will be going the electric pump route. In the day these Carter style mech pumps were bullet proof and never failed. I had one that was transfered to three engines and was still going strong when I sold the car. I do not know what has changed, but I have a sneaking suspicion it's cut rate parts.

11-10-2010 08:32 AM
obengston I'm running a Holley (AED) 750
11-10-2010 08:20 AM
What mechanical Fuel Pump?

I have a SBC 383 pushing over 500hp to the flywheel. I'm currently in the process of rebuilding the engine (ported my heads/new cam (solid roller) ect.. Well I was wanting to uprgrade my mechanical fuel pump to a better one. I don't want to go electric (yet). But was thinking of the following 2. I think the 110 GPH would be good. I like the 170 GPH but don't want to have to change over to AN fittings right now (both don't need regulators, which again I don't want to add. What are your thoughts? or is there a different one that might fit the bill. Again looking to stay away from regulators right now and electric.




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