I am running a stage 2 motor build by Jim Burek in my 70 Sport Wagon. The car originaly a 350 car of course. I am running the stock fuel lines into a stage 1 mechanical pump. The car seems to run just fine on the street. I have not run it at the track or wound her up tight in 3rd as of yet. My question would be is the stock lines capable of supplying fuel to support a 600 hp motor? How can I upgrade this without a bunch of plumbing? Can I install a electric boster pump back by the tank triggerd by a micro switch? Will I have to upgrade the lines? I have some ideas but before I try I thought I might see if anyone has any ideas. Iam running a 1000 demon carb. Dennis
In a word - NO. A stock fuel pump and lines may run a 600 hp motor around the streets, but if you start running it down the strip and get the chassis to hook good, you're going to be starving for fuel. I would suggest at the very least: 1. Get rid of the mechanical pump 2. Install a Holley blue or black elec pump in the rear by the tank 3. Install a rear sump in the stock tank 4. Install a pressure regulator near the carb with a seperate line to each float bowl Remember this is a MINIMUM set-up in my opinion. I'm running about 650 hp in my GS and I use a fuel cell, BG280 pump (rear mounted), #10 line from the pump to the regulator, two #6 lines from the regulator to the carb. One reason for a big fuel system is to overcome inertia when the car launches. You need consistent flow and pressure even when the car is trying to push it the other way. Without knowing your intentions for the car it's hard to make any more recommendations. Have fun. Sounds like a cool car.
Dennis - When I had that motor in my car, I was running 2 carter fuel pumps (the high flow version), mounted above the rear axle, and the 1/2" supply and return lines. I had the regulator mounted about 14" from the carburetor. I never ran into fuel supply issues with this setup, it would charge thru the traps at the end of the 1/4 with no hint of a problem.... There was also this one time, involving a crotch rocket on the open highway :Brow: WOT thru 2nd, 3rd, and well into OD, with the speedo wrapping back around to 0 hehehe. :laugh: That was enough fuel system testing for me LOL
Fuel Thanks for the advice guys. Looks like I have to make a decision if I am going to run her hard. Scott did you run 1/2" lines all the way into your tank? Did you have a sump. I would rather not go with a sump so I still looks sock. I their a way to install a larger line into the exsisting stock system. Scott can do you still have the Dyno sheets on the motor? If so can you send them? Dennis
Dennis - Sorry about the dyno sheets, they're still on my desk.. I apologize for my forgetfulness. As far as the lines... I did not have a sump. I wanted the stock look too, so this is what I did -- I removed the tank from the car, and removed the undercoating from the bottom side of the tank. I welded two 3/8" lines into the bottom of the tank, near the center. It's as close to the lowest point on the tank as far as I could tell, when in stalled on the car. The two 3/8" lines each led to an inline filter, then into a carter fuel pump. After the pumps, the two lines joined at a Y-block, which had two 3/8" inlets, and one 1/2" outlet. The block, pumps, and filters were all mounted in the space above the rear axle. As you know, the braided stainless line on that Demon is only 3/8", so I figured there wasn't any point to go bigger.... The 1/2" supply line ran along the passenger side frame rail, and up into the engine bay. Just off of the inner fender, I had the adjustable regulator mounted. On the regulator, I had the 1/2" supply line, a 1/2" return line, 0-16psi pressure gauge, and a 3/8" line from the regulator to the carb. For the return line, it followed the same path as the supply along the frame, then a small piece of tubing was welded into the tank near the top, where it coupled with the line simply by using a 2" section of rubber hose. I generally ran about 6 psi of fuel pressure. I don't have any "scientific" measurements of how much fuel this system would flow, the best I could do was to see how quickly it could fill a container of known volume with fuel... The most consistent figure I could come up with was approx. 85 gallons per hour, but I'm sure that would change when the system is under pressure, vs. free flowing. I never had anyone spot the fuel system, however I did point it out to a few people at cruise nights.... The most noticable aspect was the noise that it made. Driving in the car for long distances became an annoyance. That being the case, I'm taking the nasty overkill fuel system out of the car, and going back to a powerplant that can run off of 5/16" line without a problem.
Re: Fuel I do believe the famous Mr. Wiese sells a 1/2" pick-up tube that goes into the stock sending unit hole. That would be my suggestion. Putting the connections in the bottom of the tank might work, but under acceleration the fuel runs to the back of the tank, away from the ports. It could also be a hazard if the line got caught on something and torn off. Just some thoughts. Have fun.
Tri-shield (Jim W) also sells a nascar style billett aluminum mechanical pump that is supposed to flow enough volume for an 800hp motor.
