Quote:
Originally Posted by ponyakr
"...electric pump...frankly don't think a relatively mild street engine should need one..."
That sounds reasonable. And, I don't remember any of the popular carbed Musclecars that came from the factory with an electric pusher pump. If you guys know of some, please post that info.
I suppose it might depend on exactly what "relatively mild" means. My '69 RA3 4-speed GTO didn't need one, in stock form. With only about 500 miles on it, I entered it in a race at our local airport. Won the class, against some local big block Chevelles & a 442. In doing so, I made several passes down the track. It ran all the way thru, shifting at about 5000 rpm, or slightly above, & never ran out of gas.
So, by today's standards, exactly how "mild" was a 366hp early '69 RA3 engine ?
Some of the bigger cube engines come to mind, 426 Hemi with two 4's, 427 BBC, 429 Boss Ford, 440 Six Pack Mopar, BOP 455's, 500 Caddy. So, did any of these cars come with electric pusher pumps ? Surely the car maker would not want these engines to run out of fuel, which could possibly cause engine damage, or at the very least, reduce engine performance.
And, it's already been mentioned about the RobbMc pumps. They're available in a 550hp model, and an adjustable 1100hp model. With a good 1/2" supply line, one of these should supply most any reasonable street engine.
https://www.robbmcperformance.com/pr...ontiac550.html
https://www.robbmcperformance.com/pr...ntiac1100.html
The Carter M6907 should supply more than factory Pontiac pumps, I assume.
https://butlerperformance.com/i-2445...fmp-m6907.html
https://www.amazon.com/Carter-M6907-...42350075&psc=1
https://www.ebay.com/p/Mechanical-Fu...nid=1907933686
I think it has also been mentioned that a pusher pump is real handy for filling the carb bowl(s), when the car has not been cranked in quite a while. If this happens on a car without a pusher pump, I usually pour a little gas down the primaries. Since none of my race cars had a working choke, I always turned the idle screw, to keep idle speed up, til carb/engine warmed up. But, most street guys would probably not wanna have to raise the hood & do all this. So, a working choke plus an elec pusher pump appear to be good equipment for a street car, IMO. |
the fuel starvation issues happen on cars much faster than any stock car ever produced. its usually engines of 425+ hp & good drag radials getting decent traction running mid 12's or faster. none of those cars listed above were that fast, most were in the mid 13's. & drag radials didnt exist back then, street cars usually ran on hard street tires.
i have the robbmc 1100 pump & i still have fuel starvation issues with 1/2" line on good runs, it doesnt happen all the time, i can click off pretty consistent low 11 sec runs, but when i do a hard launch or take the rpms higher than usual it will cut out at the top of 2nd gear around 1/2-3/4 track.
on the street i can run as hard as i want & never see the issue, from a launch or at a roll spinning tires through all gears. the problem happens at hard launch & good traction on the track when a mechanical pump needs to pull fuel through almost 20 feet of fuel line, with bends, & try to keep a little q-jet fuel bowl full. i plan to play with the psi of the pump a little more & see if turning it up at the track will help... if that doesnt work, its in tank pump time!
also the hp ratings of fuel pumps (550, 1100) are done with them sitting still on a dyno with a short big supply fuel line, so the actual power they can support goes out the window when in the real world of drag racing. small pusher pumps like the carter are a great idea for priming the carb after sitting or as a small helper pump for some cars below a certain power level/et, but i doubt they would do much for the real fast street/strip cars.
anyone out there with 450-500+hp run a carter type pusher pump that overcomes a fuel starvation issue at the track from a mech pump? would be a cheap alternative to an expensive fuel pump set up if they did.