FrontEngineDragsters.Org Forum
Technical => Spud Miller's Cave => Topic started by: grapro on July 09, 2014, 11:43:11 AM
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I was wondering if you could hook up the high speed bypass back into the return line just under the fuel pump. Would the suction side of the pump cause the valve to malfunction or not be affected at all because of it.
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I run my returns right back to my main fuel line and have had no issues
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I ran a return line back to the tank.
I was cautioned that if it was dumped back into the feed line for the pump it MIGHT cause cavitation in the fuel.
I was also told the return should go to the front of the tank (opposite of the feed line) to avoid air bubbles in the tank or pickup.
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Been running everthing back to the inlet of the pump since '95, Closed loop hyd system and no way to introduce air unless there is a fitting leak.
Never have seen a clear fuel tank to prove the air bubble theory
Sid Waterman sells the parts and fittings to do this, I would think he is in the know about this subject
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I've heard of people having issues with returning to the inlet, but never actually talked to one of them :) I kinda think it's an old wives tale or something. Plenty of fast, successful people do it and run just fine without issues so I tell people that they should make their decision based on plumbing. On a long car, you'll save some bucks on hose by sending returns to the inlet. It really simplifies the plumbing in most cases. There's a dozen or more ways to plumb returns lines on every setup and they'll all work pretty good.
As long as you keep in mind what is going through the hose and when, you can plumb accordingly...
Main pill or idle check: It's a fire hose all the time the motor is running. If you tee it with something else, have it blow THROUGH the tee, don't branch it in on the side and force everything to do a 90 to get into the hose.
Secondary: It flows very little and only at an idle. Tee it in and branch it if you want.
Pump saver (on a K-Valve): It only works when the throttle is closed and high engine RPM. Plumb it back to the top of the hat distribution block if you're blown and keep those strips cool and lubed in the shut-down. That's where most blower wear occurs. It'll also save you returning it forward and being into the blower belt.
Shut-off return: Because it's blasting at full line size, it won't hurt to run it into a branch...pressure will not build to a level that will ever hurt anything. It certainly won't affect your tune-up! Unless you're not running one of my over-center spring brackets, then look out ;) Thanks for posting the pic and the link to that, I appreciate it.
High-speed: It only works at the very top end and has very low volume. Teeing it together with other stuff is not a problem.
Spud
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I've heard of people having issues with returning to the inlet, but never actually talked to one of them :) I kinda think it's an old wives tale or something. Plenty of fast, successful people do it and run just fine without issues so I tell people that they should make their decision based on plumbing. On a long car, you'll save some bucks on hose by sending returns to the inlet. It really simplifies the plumbing in most cases. There's a dozen or more ways to plumb returns lines on every setup and they'll all work pretty good.
As long as you keep in mind what is going through the hose and when, you can plumb accordingly...
Main pill or idle check: It's a fire hose all the time the motor is running. If you tee it with something else, have it blow THROUGH the tee, don't branch it in on the side and force everything to do a 90 to get into the hose.
Secondary: It flows very little and only at an idle. Tee it in and branch it if you want.
Pump saver (on a K-Valve): It only works when the throttle is closed and high engine RPM. Plumb it back to the top of the hat distribution block if you're blown and keep those strips cool and lubed in the shut-down. That's where most blower wear occurs. It'll also save you returning it forward and being into the blower belt.
Shut-off return: Because it's blasting at full line size, it won't hurt to run it into a branch...pressure will not build to a level that will ever hurt anything. It certainly won't affect your tune-up! Unless you're not running one of my over-center spring brackets, then look out ;) Thanks for posting the pic and the link to that, I appreciate it.
High-speed: It only works at the very top end and has very low volume. Teeing it together with other stuff is not a problem.
Spud
Spud, thanks for the excellent write-up. You should consider posting it at the FIE website, on a plumbing section, in case it's not already there.
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Spud, my brother and I were just having this conversation about the high speed you set up for me and where to plumb it.
I like the idea of running it back to the distribution block. Saves me a good length of hose on a boat, and my brother is one of those that does not want to plumb it back to the front of the pump.
Great timing! Thanks.
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Sorry just realized I said HS not pump saver.... HS will now use return that was in use by the pump saver.