STAGE 2 and fueling
I was running a 340M w/ stock lines and Champs w/ 72's. Here's what i've found:
1. AT 10.20 and 132 the fuel base setting of 44 psi plus 18psi boost, the FP was slowly falling to 56psi at the end of the run. A loss of 8 psi. The engine was "happy" in the EGT[1600*F] and the plugs were toasty tan. At this point we made 2 conclusions.
A. We were out of boost as the previous run @ 22 psi was no faster than the 18psi run. This was due to 2 factors. A PT - 70 won't do the job and the pump is at it's limit. [and we were REAL LUCKY!!!]
The plan evolved to:
1. Add a -10 pickup to the tank, NEAR the bottom. [Not a good idea to try to pull the fuel vertically w/ an external pump.]
I use an Aeroquip -10 weld bung and 5/8 thin wall tube to make a pickup. I then WASH the tank w/ Purple stuff and grind the lower rt rear flat area to remove the coating. I then drill a hole, using grease on the UNIBIT to capture most of the chips. [A unibit also makes a clean, burr free and true round hole.] I then weld a reinforcing plate some 2" X 2" w/ rounded corners so the wt of the lines don't crack the thin tank mat'l.[ The plate corners are rounded so I'm not welding to a sharp corner, thus creating stress risers!!] ALL WELDS ARE TIG!!
I then repeat the scenario in the upper left corner w/ a -6 bung and a 3/8" tube to direct the return flow down into the tank so that the pickup is as far away from the heated return fuel as possible. On a hot day, return fuel can be WAAY over 100*
REMEMBER, the OEM return line is only something less than 1/4" ID and MOST ALL aftermkt pumps require AT LEAST a -6, some want -8!!
Finally, I run -10 to the ft of the car, adapt it to -8 to the rails and use a ACCUFAB billet reg.[NOTE: I called "John" @ Accufab and he told me that he runs this same reg. on his car and has a WELDON 2025 on it.] I plumbed the return from the reg using an adapter for P/S [o'ring style] to -6. The hose near the ft of the engine is stainless braided, rest of the line is -6 Aeroquip pushloc. [NHRA legal] w/ anti abrasion wrap and Areoquip fireshield sleeve where needed.
The pump/filter is an SX system w/ a check valve at the tank outlet. Am also installing a pump voltage control for street use. I's boost controlled and slows the pump when cruising.[Makes the pump live longer]
that's about it!! Phew!
Back under my gas tank
PS: I'm scared of the 2 pump deal for 3 reasons:
1. If 1 fails, the engine doesn't quit, it just melts.
2. I would be wary of the ability of an in-line added pump to get enough volume by having to pull the fuel thru the in-tank pump.
3. Pumps set up w/a "Y". what prevents the fuel from returning thru the ck valve in the smaller pump?/ [If it even has 1]
