Holley Sniper “master kit”
 

Considering going the EFI route with the Holley Sniper platform. I’m not sold on the “master kit”.

Appears it comes with a length (20’?) of rubber fuel hose. Not much info (that I’ve been able to find) on the fuel pump. Fuel filter specs (micron rating)? Does the Sniper unit include the O2 sensor or do you have to purchase the master kit to get it?

For the additional ~$300-$400 it costs to purchase the “master kit” as opposed to just the sniper unit, would it be advisable to just source my own “kit”? (Pump, fittings, fuel hose, filters, etc.)

The sniper unit will come with the O2 sensor included, no "kit" necessary for that. That said, you will be better served getting a new tank with internal baffles and an in-tank pump vs a "universal" pump and fuel line kit with a frame mount pump. Quieter operation, cooler running pump, avoiding cavitation are all benefits here. Tanks Inc is a good place to start with tanks being about $225, 225lph pump $210, new sending unit $35 then line kit with regulator $275. This is about as affordable as you will find. You can do it once and never give it another thought.

I'll second that. I've installed 2 Holley Sniper Stealth kits here and on both cars used an in tank pump from Tanks Inc, and built/ran my own lines. Used the regulator I prefer to use, as well as a small inline filter I like using that is cleanable and filters down to the micron required for fuel injectors.

It really is a trouble free, quiet, OEM style reliability fuel system.

All the other EFI conversions I've done I always go for the in tank pump setup.

So the master kits include the Earl's Vapor Guard hose and fittings, and is more designed to 'convert' an OE fuel system.

Totally agree you should use an EFI tank from Tanks, Inc. You will get frustrated with the issues of the converted system, and end up going to a new tank anyway. Plus, you will probably have to rerun lines, and need more fittings.

One thing I don't like about the Earl's Vapor Guard is that the fittings require a clamp. Not to mention, you really don't want to run 'soft' line the length of the car (for a number of reasons).

A 25' roll of aluminum fuel line, and a few nut & sleeve fittings, and you will come out ahead in the long run. Just remember you have to flare the ends of the aluminum line to a 37 degree angle, and not the brake flare angle. I suggest either Russell or Aeroquip push lock type hose and fittings. Getting a color you want or cost may help decide.

One thing about the silver throttle body is that it hazes over with time, so I would suggest getting the black one, or spray the body of the silver one with something like clear engine paint.

With that said, couple tips:

* There is no fuel psi gauge with the kit, and you need to make SURE the fuel psi remains constant. I suggest purchasing a Holley 100 psi transducer, #554-102.

* There is no fuel regulator in the kit, so you need to get one. Use a bypass one, and choose one for you power level/line size. https://www.holley.com/products/fuel...fi_regulators/

* Use a braided brake line to hook the transducer to the regulator, and mount the transducer in a stable location. Like the firewall. Vibration kills them fast.

* Use a 10 micron filter before the regulator. (not included)

* You can use the O2 mount that comes with the kit, but they usually end up leaking. Many companies make header collectors that have the O2 bung built it. If you can't find one for your size collector/pipe, get a weld in bung, and weld it in. Same goes if you are running manifolds, get a weld in bung.

* You need to make sure you have no exhaust leaks ahead of the O2 sensor. It messes with the self-tuning.

* Make sure you can use the throttle cable and bracket you have, if not, grab a bracket and new universal cable, like a Lokar one or something.

* Pay very close attention to the wiring of the unit, follow the directions to a T, and your existing wiring should be in great condition. Including grounds and batt cables.

* The Holley forums are very good, you can get help for most common problems. The search feature sux tho, search from you favorite internet search engine.


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The 4150 sniper has an internal pressure regulator and the 4150 Stealth and Quadrajet Snipers require external regulators. FYI. I second the use of 3/8 aluminum line with nuts and sleeves. For both feed and return. Have done two cars this way and works great. Never connect the aluminum line straight to the throttle body or tank. Always have a hose between hard line and the tank and the hard line and throttle body.

I used the Holley bypass style pump that is mounted in the Tanks tank. The regulator is built into the pump and no return line is necessary. No issues.

You do not want to run that flexible line the length of the car. I used the original 3/8 hard line and added the aluminum line where needed. You can get the Russell tube fittings to connect the old and new tubing.

The built in regulator is not very good, and fluctuates a lot. It 'works', but it's not optimum.

You can use the throttle body as a bypass, but again, it's not optimum.

If you're at 350-450hp, you may not notice any issue, but you get close to 500-550+, and you notice it.

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I found a few interesting things playing around with mine Holley doesn't tell you.

Using a regulator that is vacuum referenced is a nice advantage during high vacuum and idle situations as it lowers fuel pressures a bit when it's really not needed and it makes fuel tuning much more manageable when injector pulse widths are really low. Something to think about.

Also the injectors opening and closing constantly causes pulses in the fuel rail, and can make the AFR jump around a bit, which then in turn makes low rpm and idle fuel tuning not quite as accurate. It also can play games with the self learning as well as make the fuel pressure fluctuate wildly at idle. The cure for this is to install a dampener in the rail.

I also found that by installing the dampener, the Holley sensor that I use for fuel pressure no longer has to be installed on a short piece of line away from the engine. It was never engine vibration that was causing my fuel pressure to fluctuate, it was the fuel pulses from the injectors opening and closing that caused the pressures to jump around. Once the dampener was installed, fuel pressure became rock solid, which also helped to settle down the AFR and made it much easier for the unit to self tune and much easier for me to do the tuning I needed to do.

Just some little add ons that don't come in the kit but can be beneficial.


Other things I found about dampening the fuel pulses from the injectors. Generally the closer you have a remote regulator mounted to the unit the more the regulator will act as a dampener. I have my regulator within 2 feet of the unit but found that isn't close enough to act as a dampener. It basically needs to be mounted up close on the fuel rail itself. Not an option for me so a dampener was needed. So those that run an in tank pump and regulate it back at the tank would benefit the most from a dampener upgrade. The noise it can create from the injectors pulsing, especially if using any kind of hard line, can be loud enough to hear in the car. The dampener cures that as well. Generally these noises aren't heard when using any form of a braided line as that tends to cushion the blow to some degree.

Very good info, and the 'pulses' are called fuel rail 'hammering'.

The hammering may impact the transducer, but it certainly is vibration that kills them. Even Holley now recommends installing away from engine, and offers a 'line kit' for the transducers.

I was looking at the Radium dampers, they are recommended by many:

http://www.radiumauto.com/Fuel-Pulse...Kits-P759.aspx

They have vacuum reference built into them.

Fuel rail 'hammering' is more prevalent in deadhead systems, but in some cases may also appear in bypass systems. The effect can also wreak havoc on fuel pumps too.

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Radium is what I used on both cars. Very nice product and worked perfectly. I used the one with vacuum reference built into it.

I'm running a return style fuel system on both cars and was still getting the fuel pulsing on both of them. Not quite as bad on one because I have AN braided plumbed throughout which absorbed some, but it still had it.

The other car I have some steel line I made right up on the unit itself to make it look more stock appearing. That hard line increases the fuel pulsing, not only that but it also makes a hell of a noise,, lol. It was bad enough on that one to make my mechanical fuel pressure gauge mounted on the cowl to flicker back and forth about 5 psi, and do it so fast the needle was a blur. The dampener cured both the flickering gauge and the noise.

I'm going to check mine once I get it installed, but as of yet, I'm not seeing any issue on the port setup car. Not saying it isn't there, but I don't see it in any readings/hearing.

My regulator is mounted inches from the rails tho.

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That helps. The closer the regulator is mounted to the rail the more it will act like a dampener.

It's really the way I wish mine was from the beginning, then I wouldn't be spending $150 on a dampener, but I couldn't hide the regulator to my liking up there, and make the lines appear "stockish" with a regulator so close and having lines coming in and out everywhere, so I hid all that stuff down low.

The dampener wasn't hard to hide though, as I just used it where the fuel is coming into the rail at the back of the engine so it was easy to adapt it.

Overall I'm happy with how that all turned out. It's a good piece that does what they say.

There's not a lot of real estate back there, that's for sure. I had more than most since I was using a Victor. The Dominator EFI regulator is kinda big to begin with.

I ran a -8 line to a Y under the intake, fed the rails from the from, and tied the rails in the back with the regulator. Very tight. Made a plate that goes between the intake elbow and the intake carb flange, with a short flange for the regulator.

The car getting the xFlow has a hurricane intake, not sure I can make it happen in the same location, but going to try. Less I mount on the firewall the better IMO.

EDIT: You can see the transducer in this pic, but after talking to several people, moved it to the firewall.

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That looks good. You have a lot going on there and did a nice job containing it all in the back. Not easy to do. Much cleaner than most I see. I like it.

To give an idea what I dealt with, and the reason I went with the Stealth unit was specifically so I could pull something like this off.

Basically it looks like a carb, with fake fuel line running up from the inop mechanical fuel pump that looks like it operates.

No real way to put the regulator close and pull off the sneaky nature of this setup. I did manage to hide the dampener behind the unit under the air cleaner though. The real fuel line from the in tank pump comes into the rear of the unit where it can't be seen.

I have a '65 and I'm going to be installing the holley EFI also. I'm using the muscle car fuel pump system. It uses your existing fuel tank by replacing the sender with a new sender/fuel pump assembly and the Holley hydromat.
It's rated a 255 lph. 550 hp. I'm No where near that, closer to 450hp.
The pump is internally regulated to 58 psi. No need for a separate return.
I plan on using the existing 5/16" fuel line.

Here's the link...
https://www.holley.com/products/fuel...s/parts/12-303

I'm using 3/8 aluminum line from the TB to the chassis hard line. Then the vapor guard hose to the 5/16" steel line in the frame, and at the tank.
Probably in the next month or so I'll be doing this.
I can let you know how it works if your not planning on doing yours before then.

Jeff

Thank you, it took a lot of time and patience, as well as several revisions along the way, but am happy with how it turned out.

There is a lot going on there, most don't see it all.

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Wow, that looks great! Have to really look hard to tell anything is up there. Stealth for sure!


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Curious to see how that turns out and works, if you could, please post a thread of the install, would be very helpful for others.

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I will post the install and let everyone know
Jeff