Holley Sniper EFI with Ram Air

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Hey Y’all. Has anyone used a Sniper EFI with a Ram Air housing. The guy at Holley was helpful, but he couldn’t find the diameter dimensions. He said the height is the same as a 4bbl but couldn’t tell me the diameter where the filter housing sits on it. Thanks!

 
I have the MSD atomic and it uses the dame air filter setup as my old Holley and Quick fuel carbs. I would assume the sniper does as well but you know what assuming will get you. so here you go.



14"
 





Specs




Application


Universal




Brand


Holley Sniper EFI




Diameter


14" Round




Emission Code


3




Filter Diameter


14"




7 more rows





 

Holley Sniper EFI 120-511 Sniper EFI Air Cleaner Drop Base ...



 
a friend of mine has a holley sniper efi on his 71 Mach with a Cleveland 4v. I believe he has a Weiland single plain intake with the stock ram air cleaner assembly and it fits perfectly.

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So everything is installed and the Sniper EFI works fine with the Ram Air Assy. BUT. It will not fit with the MSD Hyperspark Distributor that Holley recommends for the Sniper. Anyone else run into this problem yet?

 
Good old mallory for mine, with a dual Offenhauser, plenty space with the ram air, but I have a custom version of the plenum that goes on the unit directly without the air filter pan. Where is the dist touching?

As I will soon install another one on my 71 429, if you could post some picts of your fuel lines, tank, brackets etc... Always nice and interesting to see/learn from other installs!

 
The Hyperspark sits taller then the stock distributor so the front of the filter housing is about 1/4” from seating. I may just need to try dimpling it a bit. I’ll get some pics of the install when I can. Thanks.

7D7A8F47-1656-4B5D-9DB0-91ED31A75B69.jpeg

7D177014-895A-4269-9EC7-25891F1BD09D.jpeg

 
Before you take the hammer, what about seeking at other wires? 
Winning 1/4”  /  7mm should be possible by looking at the "L" of your wires, they are high because of the thingies on top, pretty close from the 7mm that you need. 
You could also add a thin aluminium carb spacer, potentially let it be machined down to a couple of mm to prevent to set the plenum under pressure. (or make one using a 2 mm thick aluminium plate, not very hard thing to do using a carb gasket as a template)

 
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Nice! Sometimes you get lucky!

Btw speaking of Sniper, may you'd find the Sniper bits too brutal, hard to dose accel from low rpm ( mine makes my 351c very "tires unfriendly" :)  ). Since you have your timing handled by the dist and no longer need the vacuum port behind... 

https://www.efisystempro.com/sniper/sniper-efi-system-components/sniper-efi-progressive-linkage-kit
Do you mind if I ask what you have done to your engine? Im running the Holley Sniper EFI and am really struggling with the tune. And was wondering I someone else who has one may be able to share their tune file. All I have done is a Edelbrock performer 4v intake and the EFI (Original Dist with Pertronics so no timing control on the Holley).

 
Is the Holley Sniper not self learning? I have the MSD Atomic and besides the basic setting you just drive it. Now there is a driving sequence for it to learn. Here is a link to a sniper forum which may answer some of your questions.

https://forums.holley.com/showthread.php?21663-Learning-Mode

 
It is supposed to be self learning, but it seems to be struggling. Cruising seems to be ok but the off idle response is pretty bad. The car used to be able to light up the tires with the Edelbrock, but with the EFI it almost stalls if you give it too much throttle. Im trying to work with an out of town tuner friend but thought if someone had a good basemap off a cleveland it may help as a better starting point. It seems like its really lean on tip in and then gets rich.

 
It is self learning yes, but it can learn bad things when the hardware isn't set up right. The first thing is to really check like a dozen times(make that double) that the iac is set at 0% while able to get 100%. prob is that they coupled the KEO with a prime. On mine that leaded during tests to super rich conditions and had many flooding. The second thing after that helped the too rich condition when in low temp was to update the software. Your unit is new so you should have the right one, the table for start with low temp has been revised, but who knows how long it stayed on the shelves before be sold. Go to handheld, check under files menu and check the version number then go to holley site and compare with the latest firmware version. Updating is a breeze and done in 10 mins. (lost 1/2 hour to go get a memory card to find out there is one in the handheld by default)

It was at the time of my install, like 2 years ago, advised on holley forum to pick the standard setup in wizard and unit would adjust, but later on found out that my Crane cam was too spicy for that setup and redoing a new file with it gave me a much nicer idle. Made a little trip to painter last week and it ran so strong, I barely recognize what was once my daily ride.

Aside the unit itself, make sure there is no leak at the O2 sensor. If you use the provided stainless thingy, I'd say ditch it and weld a bung, that thing will leak soon or later or is already the reason for false readings. If you use it and your headers are bit rusty, check it double.

Running a dual plane Offenhauser, I've added a 1cm thick alu spacer.  ignition is an old basic Mallory dist,  pertronix 1 , 25k+ volts coil,  8mm wires and platinium plugs. It's a 4v with quench chambers, forged piston with 10.5+ compression. No killer engine but more than enough for me and my tires:)

I'll test ofc much more once i'm allowed again to drive the car after its tech control in a week or two from now.

 
Ended up chatting with the Holley support line tonight and he gave me a couple things to try. On top of that he blew me away a bit when he asked me to send him the data logs I had taken and the tune, and that he would take a look at it. So will see what happens and hopefully I have an update before too long. 

 
EVERYTHING WENT BAD AFTER THE FIRST DRIVE!
      So I got everything done on the Sniper install and did the initial programming. The first day out was great. Put about 200 miles on, stopped at a couple of cruise ins and it ran great...BUT THEN...went home and later that night tried to drive again..PROBLEMS!
It’s a little harder to start now but the bigger issue is a stumble and miss on acceleration. I can hear a ‘rattle’ in the engine when I accelerate that I think is a spark knock? 
 I’ve tried everything. Triple checked for vacuum leaks. Replaced the vacuum lines and the trans modulator Valve just to be sure. Then I routed all of the lines to the tree on the back of the intake, just to get vacuum away from the Sniper to rule that out.
The distributor & ignition Is a new Hyperspark set up that Holley recommends for the Sniper. The plugs and wires were new and looked great but I owned the wires and changed the plugs anyway. MSD wires Autolite gapped to 42. 
I did the old  “spray carb cleaner around the intake manifold to check for vacuum leaks” trick 
I’ve gone thru the troubleshooting chart and everything checks out ok. I reprogramed the Sniper several times. The  O2 Sensor looks good. Everything is “within the reasonable AFR targets” IAC is at 6-7. The problem is quite not as bad with my timing set at 15* idle, 36* cruise, 34* WOT. 
I called the Holley tech line twice but sat on hold both times for over an hour but never got thru to anyone.
Everything from the air filter to the fuel tank is brand new. If it hadn’t run so good the first time out, I wouldn’t be so confused. Does anyone see what I’m missing here? Thanks!

 
Also, I set up the wiring the way Don instructed and should not be getting any RFI since everything in the system is matching Holley components and made to work together, but I guess if any of that was a problem, it wouldn’t have run so good the first 200 miles? 

 
Have you checked the timing to make sure what you set it at is what the system is actually putting out?

Edit: Are you sure what you're seeing on your harmonic balancer is the correct timing? Condition of harmonic balancer, slipped outer ring?

Before you connected all of the new fuel lines and tank did you flush them out, especially those after the fuel filter? Have you checked the fuel pressure and volume after the fuel filter?

Have you rechecked all of the electrical connections and actual voltages at key points?

How did you check the O2 sensor?

 
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Thanks Don. Voltage & grounds are good at all connections. I even went back and replaced a couple of connections just to be sure. I did flush the new lines and new fuel tank At install but removed and checked today just to be sure. I just did a removal and visual check of the O2 looking for any debris etc..

 I hadn’t thought about the harmonic balancer. I’ll check that out and I’ve just been going by the hyperspark and sniper for timing numbers. I’ll put a light on it also. 

 
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