sniper fuel pressure to high?

[Brave Salmon]

Hey cobra owners, I'm posting this here as I know you have tons of Holley Sniper experience on this forum. My car is the '33 hotrod with a brand new BPE 347 motor. Holley told me I do not need a pressure regulator beyond what is built in to the sniper. My pump is a wahlbro 225 unit in the tank rated up to 100psi. With motor running at idle, the gauge on the input is running at about 70psi. I have not yet driven the car as I am worried this may need addressing before I try to go through the learn process in the sniper. I read several postings on various boards about Sniper having faulty regulators. I will call them the first of the week and see what they say. Is this high pressure going to cause any problems to the sniper and will it adversely affect the calibration of the thing? Thanks for any suggestions. tom

[FF33rod]

Tom, the situation you describe is perfectly normal and is identical to my own. 70 psi feeding the sniper, the sniper's internal regulator will bring that down to what it needs (which i believe is around 58 but dont expect that to show up on the external gauge). It runs great, go for it!

[Papa]

I have spoken with a local tuner that specialized in the Holley Sniper and he told me that Holley has had some issues with the pressure regulators and has a fix. The Holley is factory set to operate at 58psi. Here is a useful note from the manual:

NOTE: Fuel pressure should be checked on the inlet fuel line before initial start up during the fuel pump prime. We recommend Earl’s Part Number 100187ERL (0-100 psi Liquid filled gauge) & AT100199ERL (-6AN Gauge Adapter) to check fuel pressure.

[Railroad]

In using return line pressure regulators, it is necessary to have a low restriction return line.

[Brave Salmon]

Thanks guys. Fwiw, I am using Earles adapter and a Fitec gauge on the inlet port. Upon power on, gauge spikes to max and stays there til pump shuts down. Then pressure bleeds down to near zero. Start motor and it levels off at 70 while running. Yes, I've read about the regulator issue at Holley and I will call them tomorrow. I tend to believe there is something wrong with the regulator. The return line is -6 above frame rails and original 5/16 metal tube along the rail. Return pressure is below 5 using same adapter and gauge. I'll post there response when I figure this out. Thanks

[Brave Salmon]

Ok, I spoke to Holley support. They had me remove the return line from the sniper and fab up a new line directly from the sniper into a gas jug. They must have lots of bad return line issues. It did as asked and with motor running, I still get 74 psi on the inlet. They confirmed that the sniper has a bad regulator and perhaps a bad cover as well. The new parts will be here in a week or so. FF33rod, you might want to have yours looked at as well because they tell me that high pressure may end up causing driveability issues. The test only took a few minutes and it pretty much solid proof of a problem regulator. I'll update this after the repairs are made. Thanks all..

[FF33rod]

feeling really dumb at the moment because I don't understand why there is a problem.
The input pressure is measured as 70 psi, that's not a problem, it needs to be higher than what the internal regulator is going to reduce it to. So how do you know the internal regulator is malfunctioning? It would seem that to measure that one would need to attach a gauge to an internal line of the Sniper (after the regulator) Asking for a friend

Steve

[Brave Salmon]

feeling really dumb at the moment because I don't understand why there is a problem.
The input pressure is measured as 70 psi, that's not a problem, it needs to be higher than what the internal regulator is going to reduce it to. So how do you know the internal regulator is malfunctioning? It would seem that to measure that one would need to attach a gauge to an internal line of the Sniper (after the regulator) Asking for a friend

Steve

Don't under rate yourself, Steve. It made no sense to me either but Holley says that the entire unit is pressurized until it exits from the return port. So if the input pressure is 70psi then everything internal like injectors, seals, gaskets, etc, are all at 70. What Holley, and most mfgs do is use the regulator on the return side to balance internal pressure to that magic 58psi they prefer. In essence the sniper uses 58psi and dumps the excess down the low or no pressure return line. If the regulator is on the input side where would the excess pressure bleed off? You would need another return line from there. I hope this helps clarify and if I am incorrect someone will for sure correct me. Poke around online and see that this issue is plaguing Holley quite a bit. My BPE motor may have sat on the shelf for awhile and did not get any fixes Holley made to mfg process once these things started failing. I'm assuming your sniper could fall into that same age group, explaining why it's acting just like mine. Is there a date code or sn on these things? Hmm, interesting.
Good luck
Tom

[rich grsc]

It is a single stage regulator, not a dual stage regulator. The gauge is reading the regulated pressure, all excess is returned to the tank.

[BluePrintEngines]

an EFI return line should only have 0-3 PSI of return pressure. 5 is on the high side, and i'm guessing why they are deeming the regulator is faulty, as thats creating high pressure on the inlet side too. The psi the fuel pump creates will generally be higher than 58. Then dropped to 58 by the sniper regulator. A gauge on the inlet side is only going to show what the pump is putting out.

Also BluePrint Engines factory five packages are pretty much built to order. So it wouldn't have been sitting for very long here. It should be ready to roll, and probably dyno'd less than a week before received by the customer.

Sounds like you got it hammered out with holley, buy any assistance we can be, don't hesitate to ask!

Johnny - BluePrint Engines