quote:

https://www.smileysracing.com/...oads/get.aspx?i=8831

sorry im confused,again

maybe the idea is about not being able to get rid of the fuel.i dont lnow.the orfice size may be the key to that.if it was me i would plug the pump bypass and use a areomotive bypass at the carb.

Think about this for a minute, if you have a bypass electric pump and dead head regulator set at 7psi and have 24 psi of pressure at the pump.
If you block the pump bypass port and install a bypass regulator at the carb set at 7 psi, you will still have 24 psi of pressure at the pump.

I agree that a bypass regulator at the carb will give a more steady and consistent pressure to the the carb, no argument there but it will have no effect on the pump pressure output itself.

This thread began as running a electric pump on 16 volts and reducing the pump pressure so the pump will live longer.

BTW, my Magnafuel 500 bypass pump has a 16 volt label on it, that tells me it is rated for 16 volts

not sure about that steve you will have 7 at carb but with bypass operationg the actual pump pressure could be lesser

Rusty, if you only have 1 bypass in the system how does the pump know if it is on the discharge side of the pump or at the carb?

Now if you had 2 bypasses, one at the pump and one at the carb then yes you absolutely will drop the pump pressure

On my old Vega I had a magnafuel 500 pump with pump bypass blocked. I used a aeromotive large 4port bypass regulator near the carburetor. Pressure gauge back at the pump always read same pressure as gauge on the regulator. The regulator is what controls the pressure in the system. The pump only moves the fuel through the system.

Wooley, So what you’re saying is the bypass regulator at the carb flows more fuel than the bypass regulator at the pump. Now that make sense.

there wont be pressure on the pump because it is bypassing

Steve, yes the bypass regulator at the carburetor took care of all the fuel for bypass. The key to make it work was making the return line larger than the feed line. I could dial pressure as low as 3 1/2 pounds or however high I wanted it. Pump ran wide open all the time. Was quieter and less amp draw too.

Only way I could get the 16v to work was with magnaflows newest -12an bypass regulator. You need to be able to dump pressure to achieve the desired carb pressure from a much higher line pressure. The only way to do this is to increase the volume of the dump side.

There is so much flow with 16v on these pumps you need the larger volume on the dump side.

I have the regulator here and can sell it. I switched to a belt drive pump and cell up front. So the regulator BLP wanted me to use replaced this one I'm referring to. Let me know if interested I'll give you a good deal. Otherwise go back to 12v. You'll forever go round and round. Ask me how I know. I spent 4k dollars on regulators, lines, and fittings. Then went to belt anyways.

quote:

Originally posted by Big Steve:
Installed the lighter bypass regulator spring today that Top38 recommended. It had a standard spring that was cut down in it.
With the lighter spring at the same setting pressure was still 24lbs, if I backed the regulator off much more then it would start to leak thru the threads.
Cut the lighter spring down a few coils and was able to get the pressure down to 21lbs, that was lowest I could get it.
I got the new converter installed and will go test next week

Take the by pass system apart and drill a larger hole in the bullet. Measure it first then sneak up on the size hole you need. Good Luck

quote:

Originally posted by Jackie Glisson:

quote:

Originally posted by Big Steve:
Installed the lighter bypass regulator spring today that Top38 recommended. It had a standard spring that was cut down in it.
With the lighter spring at the same setting pressure was still 24lbs, if I backed the regulator off much more then it would start to leak thru the threads.
Cut the lighter spring down a few coils and was able to get the pressure down to 21lbs, that was lowest I could get it.
I got the new converter installed and will go test next week

Take the by pass system apart and drill a larger hole in the bullet. Measure it first then sneak up on the size hole you need. Good Luck

I have tthe pump pressure down to 21 lbs, going to do some TnT this weekend and log the fuel pressure at the carb and see on steady it stays and go from there. I have it at 6.5 lbs

are you going on sunday steve

quote:

Originally posted by rusty:
are you going on sunday steve

Saturday that way I can rest on Sunday. They start their summer schedule on Sunday and gates don't open until 4pm, makes for a late Sunday and i'm old

i didnt they were testing on sat looked someting else going on

They do but it includes TnT

Made some test hits with the s10 Saturday night, except a quick spike down to 5.5 then back up at the hit, the fuel pressure at the carb was basically flat lined at 6.6 psi the whole pass.

Ran back to back 5.32 @ 129 off the trailer