Fuel pressure regulator failure?

[beanhead]

Please also bear in mind that experts can also quite easily overlook the basics.

They are more 'in-tune' with their CHEVY ENGINES......

 

[kiwigtx]

This is the basic layout, the 2x4 doesn't have the internal regulator like the single unit does so the plumbing is a little different. I would mount the regulator as far to the front/nearest the TBs as possible.
View attachment 1520006

I was told that 'Dead-heading' is not recommended for the Holley Sniper setup. The fuel needs to flow through the throttle body(ies) for cooling as well as maintaining fuel pressure and flow.....that is - having a dedicated Return line from TB to tank.

I thought I could get away with that also....but it won't work. The result was fuel starvation. I would be interested to know if the OP has done this as per your diagram @beanhead

 

[beanhead]

View attachment 1520013

I was told that 'Dead-heading' is not recommended for the Holley Sniper setup. The fuel needs to flow through the throttle body(ies) for cooling as well as maintaining fuel pressure and flow.....that is - having a dedicated Return line from TB to tank.

I thought I could get away with that also....but it won't work. The result was fuel starvation. I would be interested to know if the OP has done this as per your diagram @beanhead

Interesting, I know they prefer to position the regulator after the fuel rails on a port-injected system..but I've never done it that way with the TBI kits and things worked fine. The standard Sniper, yeah the return line was plumbed directly out of the throttle body unit but it had the internal regulator.
Of course, I've not done a dual-TBI install(yet!)

 

[kiwigtx]

Interesting, I know they prefer to position the regulator after the fuel rails on a port-injected system..but I've never done it that way with the TBI kits and things worked fine. The standard Sniper, yeah the return line was plumbed directly out of the throttle body unit but it had the internal regulator.
Of course, I've not done a dual-TBI install(yet!)

I think the standard Sniper unit with its built-in regulator is more susceptible to any fluctuations (Hey I know a joke about that) and large differentials in fuel pressure & flow. IMHO Dead-heading would be a factor here.

 

[Geoff 2]

The return line should be larger than the feed line, so that it does not cause a flow restriction that affects pressure.
300 gph pump? The engine is making 3600hp? Because 300 gph is enough to supply a 3600 hp engine using pump gas.

Choking down a hugely oversize pump is going to make it hard work on the regulator.

 

[kiwigtx]

Choking down a hugely oversize pump is going to make it hard work on the regulator.

Which is why I said dead-heading should not be done.

The return line can be the same size as the supply.....return fuel usually runs at around 4-5 psi.

 

[Geoff 2]

Uh, no. Not according to the instructions that came with my Mallory by pass reg. Return line is recommended to be BIGGER than the feed line.

Also, the return line pressure is the same as the feed line. That is how a bypass reg works: it is one continuous fuel line & somewhere along the way, the carb takes the fuel that it needs.

 

[beanhead]

To repeat, you do NOT need the return line to be bigger than the supply line with your EFI system. Would it hurt? No...it'd just be a waste of money and time.
Many EFI users even have the return SMALLER than the supply and things work great, though that's not how I do it nor would I recommend it.