I'm thinking I want to install a bypass regulator to use with a 2nd gen piston lift pump. I am planning on installing the regulator after my filters. Now for my questions:

1. What regulator are you using is you are using one? I know BC is using the $200 aeromotive regulator, but i'd really like to find a cheaper alternative. But it may be the best most reliable setup and the boost referenced increase would be nice.

2. Where should I monitor fuel pressure, before or after the regulator?

3. Is between the filter and the IP the best place to install the regulator?

4. Do I really need a boost referenced regulator? As with the 2nd gen pump there may be enough pressure to push the front seal out of the pump. But on the other hand at higher manifold pressures you're using more fuel so maybe the actual pressure the seal sees is relatively constant?

Thanks for the info.

Aaron

 

1. I chose that regulator as it was one of very few (that I could find) labeled as diesel compatible.

2. After filter(s) and regulator, just before the IP.

3. Yes.

4. I think that with the 2nd Gen LP and big injectors, no. My DDP4's can pull things down to about 8psig @ WOT. With smaller injectors, maybe. I don't know.

I would recommend that one strongly consider running a minimum of 3/8" ID hose for the bypass return to the tank. I'm currently using the OEM fuel supply line and it appears that . . . at WOT, wound-out, just after crossing the finish line, when one gets off the throttle. The engine is still wound up, with the LP still getting it. The fuel demand of the IP goes to minimum and the bypass of the regulator goes wide open to dump the excess of fuel back to the tank.
In the above settings, that little OEM line can't pass all the fuel thus the pressure in the regulator itself goes out the roof. In my mess, that results in a what appears to be a very small amount of fuel burping out the case seal of the regulator.

I gotta fix that.

 

Thanks for the fuel line recommendation, I was already planning on replacing the return line with 3/8" and just tying all 3 returns to the same 3/8" line.

So with your findings on pulling fuel pressure down that low at full throttle a boost reference regulator doesn't really give you anything. You could then use the bypass that Wannadiesel used, or the 2nd gen guys use with their walbro pumps. But would these regulators be up to the task when used with the piston pump and the associated pressure spikes?

Thanks, Aaron

 

This is the one I have http://cgi.ebay.com/ebaymotors/Aerom...mZ120304957105

I monitored in a "T" at the IP. and the reg was right after the filters.

 

At your current fueling I don't think you need a boost referenced reg.

I would consider a front pump seal retainer (or at least a good loctiting) essential for a boost referenced system.

 

When I resealed my pump I red loctited the seal in pretty good. But it doesn't sound like even the 2nd gen pump with lots of fueling can keep up to take advantage of a boost referenced regulator anyways. So whats the point, unless you're going to go with a walbro pump or something.

So I think i'll go with something like the simflo pressure maintaining valve as my bypass. Much easier on the wallet. haha

thanks, Aaron

 

Should work just fine.

 

I was gonna be all helpful and post a link to VULCAN's SimFlo bypass regulator; but, alas, they seem to have dropped it from their product line; does anyone know why ??


I had intentions to buy two of them for a couple of my projects; I guess I will have to find them elsewhere.

 

Yeah both vulcan and gds don't seem to list them, the one site that has them is wide open diesel, but if you go directly to their site there is nothing there, but if you search there is a link on one of the forums that takes you to the page. So I don't know whats up with that.

But yeah, would be nice to know why they dropped it.

I've also searched mcmaster for a cost effective replacement, but didn't really come up with anything I thought would work, for the same price.

Aaron

 

One thing I failed to mention in my earlier post about why I chose that particular regulator. My thinking also included the recognizing that the LP's output is pulsed. I figure that takes it's toll on a reg. I figured one with a larger ball wouldn't be beat-up so quickly.

If that makes sense.

 

I just purchased a bypass for a different application from
www.kinsler.com Might be worth a look. They have quite a variety of fuel parts I didnt see simflo but nor did I find anyone who had simflo on the net for my brief search everybody was out of stock. They were very helpful and knowledgeable. Anyway might be worth a call. If you look in their catalog check out page 35m for bypass valves.

 

What does everyone think of this pressure valve?

http://www.swagelok.com/search/produ...part=B-8CPA2-3

It seems like a few 2nd genners are using this with their electric pumps, my only concern is how the spring would hold up with the pressure waves of the piston pump.

Any thoughts?

Thanks, Aaron

 

I think it'll be OK. It's not really a critical application if you think about it. If it fails, you will lose most of your fuel pressure, but the truck won't die. There will still be fuel available to the vane pump at the front of the VE, just at low pressure.