greencard

iTrader: (2)

I have blown 509's and Edelbrock race pumps with NO regulators(8.5psi) and large fuel lines. This works at low boost/740hp, but how much more can these pumps support? The engines make 850hp with the boost turned up....but thats when things BROKE!! Thanks in advance for replies and please do not reply unless you have a proven combination.

WeaponX

I run hi press. mech and 1100hp. Did you change your jets for the new boost. That's one of many things if you change a set up gap,timing,fuel,fuel delivery. What broke or melted? Post pics. 8.5 without regulaters is the wrong pump you need the hi press.

HUSTLEthis

What 3600cat said...

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iTrader: (2)

Riddle me this....the engines WERE dynoed with both pulley sets, to our surprise jetting was actually fatter turned up(faster blower sucks more fuel thru carbs) and timing is at 30 deg total. This was done at a very reputable shop on a superflow dyno, regretfully I did not use my fuel pumps. The pumps are the 13 lb race pumps with a small spring removed from the diaphram, this gets you to the 8-9lb range...A direct copy of what Mr. Teague uses on his 800hp engine. How do you hold 13 pounds back with your carbs, mine seem bearly capable of holding back 9 with all new good tipped seats and the floats not cranked TOO low. The piston broke off an edge above the relief and all pistons in both engines looked white in the same area. Note my fuel lines and carbs are merc 800sc parts, they are none too big but they did work for Mercruiser on a much larger displacement engine...at less RPM's however. Keep it coming! Hustle what is your combo?

catcando77

I have had a similar problem with my mechanical pump only i have had a pressure drop problem. My engine dynos at 822 at 5800. The pressure drops from 5000rpm to 6000 rpm i start at 6 psi and drop to 1 psi. No good . I did not have a regulator as the pump is self regulated 150 gal/hr rated. I am suprised your carbs did not flood at your pressure.
What i have done is purchased an aeromotive pump changed all lines to twin #10 to a y block and added the boost referenced regulator to twin #6 carb lines rather than a dual fuel log. I hated this season as i spent alot of time tracking or looking for the problem. One note on my system it was rigged with the fuel being pulled through the water filter.This is a mistake as this lowers pump performance a they push better than they pull. Hope this helps

CNC

RACEPUMPS (http://www.racepumps.com/) makes a cool fuel pump. I haven't used it much, just tried it at the end of the season, seems to show potenetial

WeaponX

You have to have regulaters with a hi press pump set them at 9 psi and it will stay at 9psi. No more trouble. And keep the regulater as close to the carbs as possible.

tomcat

greencard: Where do you measure fuel pressure?

catcando77: We use the Aeromotive A1000 pump on blowthrough and EFI supercharged up to ~875 HP. A #10 line from tank to a large (1/2" NPT) water separating fuel filter to the inlet of the pump. We use the large water separating fuel filter in this postition for two reasons: to guarantee prime on the electric pump and as a place to put the fuel being returned from the regulator through a fuel cooler. You're right, it is a restriction on the inlet of the pump so you have to lay out the lines with sweeping turns and no hard 90s.

CNC: I guess you would definitely need a regulator and return line with that piston pump.

greencard

iTrader: (2)

Tomcat, I also use a quart draw thru with #10 from the tanks to the pumps and #6 to the carbs. I measure press in a t on pumps output. I realize I should measure in the end of my fuel log to carbs but I still think the setup should be adequate.

2112

One note on my system it was rigged with the fuel being pulled through the water filter.This is a mistake as this lowers pump performance a they push better than they pull. Hope this helps[/QUOTE]

Interesting, most manufacturers advise the filter ahead of the pump. I assume you have an inline filter between the tank and pump?