Fuel Pump capacity needed for 2.5 Drag

[CI STV]

This one is for all you Merc 2.5 gurus on here. As the title says, what’s the recommended rating for fuel pump capacity for a serious Drag setup, running ~56 psi on race gasoline?
I know the standard go-to is the Weldon A2005-A pump, which pumps around 95GPH @ 56psi with 14 volts, which equates to ~585 lbs per hr.
I know that’s what Mercury recommended during the last years of production for the 2.5Drag, and before that it was the Bosch, I think?
The thing is that I would really like to install one of the fuel cell modules with an internally mounted fuel pump, like the Hyperco or Aeromotive. But both of those come with either a 340lph pump which only produces around 500lbs per hr. which I suspect is not enough to feed a ~360hp modified Drag motor?
The Aeromotive can be had with their A1000 or Eliminator or a number of their ultra expensive brushless pumps, but I’m thinking any of them (with probably the exception of the the A1000) would be serious overkill.
I want to get this right, since fuel supply is probably the most crucial thing on a two stroke motor, so any insight you can provide on this topic would be greatly appreciated.

[Chaz]

2.5 .. I don't know ..
But I know of an old POS Holley blue that made a Big Chevy run into the nines about 35 years ago .. That was before Barry Grant took out full page adds in National Dragster every week claiming that you needed one of his 400 gal/hr pumps , or your motor was gonna die .. you'd never win a race .. etc.

Da maff don't lie ..

A gallon of water weigh's 8.345 lbs.

I like .700 gas ..

A gallon of "CI STV" gas with a SG of .740 weigh's 6.1753 gal .

Mentioned pump blows 95 gal / hr . 95 x 6.175 = 586.653 lbs/hr

BSFC on a normally clean running 4 stroke is usually rounded off to .5 lbs to produce one hp. Low .4's if your real good ..

A two stroke is a bit dirtier , lets call it .6 586.653 / .6 = 977.755 HP

OK lets run it plug fouling rich .7 586.653 / .7 = 838.076 HP

It's not mechanical fuel injected , but lets say your a guy who believes that a pump is sized correctly when you send 50% thru the motor and 50% back to the tank ..

Using the overly rich numbers .. 838.086 / 2 = 419.03 HP .. yea , a 95 gal/hr pump should be enough reserve capacity … LOL

Personally I use the Bosch 044 on everything . The Porsche guys I work for even use them on carbureted applications …

[CI STV]

Thanks Chaz. I remember those days when Barry Grant was “The carb man”. Until he went bankrupt.
Thanks for the math. The one thing I didn’t know was the BSFC for a 2 stroke.
Looking at your calculations, it’s crazy that Mercury recommended that big-ass battery life sucking Weldon pump.
The pump I’m looking at is actually only rated at 340LPH, and delivers ~ 500 PPH or ~81 GPH at 56psi.
By your calculations, that should still be fine.
I know what you mean about the Bosch 044. Probably the most dependable pump ever made. Thanks again.

[CI STV]

This is the fuel tank/pump module I’m thinking of using:
https://hyperfuelsystems.com/products/49106/

[H2OPERF]

Have you looked at the radium engineering units , super nice.. and they have ones made for the 044 pumps, I helped a friend put one in a subi. Personally I'm not crazy about the ones with caps on the tanks.

[CI STV]

Have you looked at the radium engineering units , super nice.. and they have ones made for the 044 pumps, I helped a friend put one in a subi. Personally I'm not crazy about the ones with caps on the tanks.

Nope, but I will now. I was just on their website the other day because I’m considering their very nice fuel rails for my Vette.

[H2OPERF]

I may have lied, looks like the one for 044 is only external now, it shows a fuel lab pump in the unit that had an 044... probably bc alot of people are going to brushless where you can control the pump speed with an ecu. I went with the brushless 105gph fuel lab in my boat.. she holds 60psi solid but its kinda noisy though its not bad when i hit the 1/2 speed switch for idling and long channels a funtion i will put on the ecu when i figure that out lol..

[Chaz]

Store bought tanks , Fuel Lab pumps , ECU driven dimmer switch's …
Opp's I'm sorry , I didn't relize this was the $500.00 dollar table . can someone point me to the "quarter (.25c) slot machines" ..

[H2OPERF]

He posted a $500 tank so i posted what i thought was a nicer $500 Tank LOL.. I dont have one but i did want it...I put a $20 flap door in the aft baffle and called it a day... Brushless is the ticket though say goodbye to pressure regulators.

[CI STV]

LOL! My $500 (actually $570) tank comes with a pump, gauge sender, stainless hardware and is black anodized, so it looks like a bargain to me.
The radium tank is big bucks when you add in the module with the pump, etc. I guess you get what you pay for, most of the time.
Fuel labs makes badass pumps to.
But, I’m just looking for a simply, clean fuel cell solution where I don’t have to piece it together bit by bit or worry the pump being exposed to the elements.
The in-tank pump thing is what the OEM does with all their cars now anyway, so it can’t be all bad, right?
This is going in a lightweight drag race only STV, so I only need a 5-6 gallon cell, but I want to make sure that the motor has enough fuel.

[H2OPERF]

Crap, sorry I wasnt payin attention i thought that was a swirl pot, cant see on these phones without glasses anymore looked much smaller than 5 gal. fuel lab pumps can go in the tank too.