Considering Holley sniper EFI for my 1969 340. Thoughts from people who have that set up?

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harrisonm

harrisonm

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I know that over the years I have said I would not switch over to EFI on my Barracuda because it ran fine on a carburetor. I think I am about ready to make the switch. I am getting tired of having to crank my car until gas gets up to the carburetor if I have not run it for a week or so. I’m also kind of getting tired of fiddling with the carburetor. It seems like every once in a while it wants to be adjusted, or the choke wants to be fiddled with. I am interested in hearing from people who have the Holley Sniper on their car to see how they like it, and if they have been any problems. Prefer hearing specifically on a 340, but I guess any inputs would be helpful. I guess the base unit now is the Sniper 2, so comments from people with a Sniper 2 would be especially helpful, but any Sniper comments would be appreciated. I currently have a complete MSD set up to include their distributor. I really want to keep that.
 
Sell the MSD and grab the latest version of the Holley Sniper. AndyF & Fastman EFI are the experts on these set-ups, and both are on this forum. They forgot more than most know about the Holley Sniper systems.
 
I always say this but it makes little sense to run the Holley EFI without the Hyperspark ignition system. Being able to control the timing through the ECU software is a major benefit of the conversion to EFI. Without the timing control you will be leaving performance and drivability on the table. If you are dead set on sticking with your MSD ignition I wouldn’t even bother with the expense or hassle of the EFI, just stay with a carb.

How is the wiring in the car? Another thing I always suggest is to re-wire the car before trying to install any EFI system. You need clean power and want to avoid creating wiring situations that will increase the chances of EMI causing problems. That will definitely happen if the wiring is a mess. EMI (or RFI) will cause no end of frustration since it really has nothing to do with what the program does except that it causes it to not work right.

Don’t skimp in the fuel system either. An in-tank pump is the way to go. Also I’d sat ditch any rubber hose and worm clamps and get -AN fittings for the connections. Don’t want leaks at 60psi.

And last - consider how involved you want to get with the tune. A lot of guys won’t touch a lap top but that’s really how to get the most out of the system. Building custom fuel and ignition tables in the software goes a long way in understanding how it all works. The initial “wizard” tune is generic and is really only there to get the car started. It takes some time to figure out what the car needs.

It really does not matter what size engine you have. Eventually the program will adapt to your driving style. I had a Sniper on a mostly stock 383 for thousands of miles and there were no issues.

Again, if you think you’re just going to plug it in over a weekend and suddenly the car will run perfect don’t waste your time. Invest in all the right components and be willing put the time into the tuning process and you will get some to ing out of it. GI GO as they say.
 
NC Engine Builder said:
You will spend a BUNCH more time fiddling with, and learning to tune ANY aftermarket EFI system.
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I agree that initially there is a big time investment but that will diminish quickly if the user takes an active role in the tuning process. The tuning concepts are the same as they would be with a carbureted engine they’re just presented in a different format.

That said, if you’re not computer literate or are not comfortable tuning with a laptop then it may not be worth the aggravation. It’s not hard software to learn but it does require basic computer aptitude. If you can navigate file folders, fill in fields and perform basic file functions like ‘save as’ then you’ll be fine. If you can’t handle that stuff in 2024 then just throw in the towel and go back under your rock.

For me, having the tuning parameters laid out as a graphical representation actually made the process easier since there is no guessing. Each cell in a table or point in a data log trace has a value. What that means is that it either ‘is or it isn’t.’ Not so much when dealing with mechanical parts.

The software also gives the user much more finite control over the tuning parameters. Maybe you have a flat spot during acceleration and one or two points on an ignition or fuel curve are out of whack. You can change the values for those cells but leave the rest of the curve alone so there’s no residual affect on any other points. That in itself overcomes the stack up of tolerances when dealing with mechanical devices.

Again, yes, there is a time investment but that should be understood. My Dodge never ran better with the Sniper and even got better mileage. 100% win and worth the time.
 
Start with the fuel system. Check to see if you can buy a complete EFI tank with build in fuel pump for your make and model. If you have a late model Barracuda you shouldn't have any issues, the early ones might be a problem.
I wouldn't buy a Sniper until you know that you can buy a tank with an internal pump.
The Sniper will work best if it is paired up with a Hyperspark distributor and a CD box.
 
There are several ways to skin a cat when it comes to fuel systems. I used a surge tank system, which has some significant benefits not the least of which is providing virtually air free fuel delivery at very low fuel levels even as low as a gallon or two under spirited road course driving.

The tank pump circulates a high volume of fuel at near "0" psi up to and back from the surge tank to the fuel tank. I silver soldered in a like-sized return line to the sending unit, sourced the electric pump 12V pass-though and the surge tank from Radium Engineering.

The surge tank circulates the fuel through the fuel rails and back to the surge tank through a pressure regulator. Any air trapped in either circuit is purged back to the main fuel tank via the main fuel return line.

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I bought the retrofit Holley in tank Fuel pump that replaces the stock sending unit in my 74 Duster. It is a great kit. It is currently feeding my carb through a regulator. Maybe do that first. It definitely solves the problem of empty fuel bowls after sitting. If you still want EFI, you'll be 1/2 way there because the fuel system will support it.

Cley
 
look for the tanks inc. efi tank. dame as the holley but cheaper. summit sold a kit that included the tank, straps, pump and sending unit.
 
My Dodge A100 has a custom made tank and an in-tank Holley pump. All the lines are -6AN from the tank to the Sniper 1 unit, and same as the return.

My engine is a 408 BluePrint stroker (360 Magnum) and runs strong. Wiring has been completely re-done as per FSM with only deviations being power studs for main junctions instead of the factory welded splices. The fuse box has also been swapped out for blade fuse blocks for ease of roadside replacement.

While I have not yet upgraded to the Hyperspark system, I see that in my very near future. The Sniper does have a self-learn program but that really is just a basic tune like others have said above.

Best thing you can do is read the instructions carefully, then read the again. Do not try and short-cut the instructions. Do not take advice from guys who have never touched one of these before......the know-it-all's who say do this and that know nothing.

Consider joining up with a dedicated EFI/Sniper forum as it will get you the best information available. There are other sources for training and learning on the net.... I signed up with Joe Simpson and his 'Tune Trilogy' before discovering there were others around. Joe has lots of information for learning.... he may not be the ultimate guru in some people's minds, but I have learned more than I ever thought possible watching his tutorials. You can never learn enough about EFI and these TBI units.

My personal thoughts on the Sniper upgrade - I wish I had been able to do this sooner. I was getting sick of carbs that leaked and were always needing adjustments. Muy wife was getting sick of the smell of gas and exhaust fumes filling the house and garage. Sick of breaking down roadside due to bad carbs, or temperamental fuel delivery.....best thing I ever did was get a Sniper.
It's no magic bullet, but it sure is the best I have had. :thumbsup:


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I have the older Sniper 1 system. I've had it on my 408 for a few years. I ran it with a points ignition for awhile, then ran it with a stock electronic ignition and finally upgraded to the hyperspark distributor. I used the Holley in tank sending unit replacement. I plumbed the fuel pump to the factory 5/16 hardline. The in tank pump also has a built in regulator so no return line is necessary.

Being able to change idle RPM, base timing, timing curves, rev limiter, launch RPM, electric fan on/off, etc from the driver seat is pretty nice. I plan on adding nitrous eventually and the sniper 1 has an option for that. I think you lose some input/outputs on the sniper 2, I could be wrong on that.

I have no regrets and I don't plan on ever going back to a carb. I'm currently swapping a 440 into my '69 D100 and have a carb. I'm fighting the urge to switch to a sniper on it also.
 
One more recommendation - given the chance to start a new system again, I would use the new Holley Power distribution block.
It would make installation a lot cleaner and eliminate the usual problems that a lot of people have.

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https://documents.holley.com/frm36866.pdf

Apparently it also works on Sniper 1.
 
kiwigtx said:
One more recommendation - given the chance to start a new system again, I would use the new Holley Power distribution block.
It would make installation a lot cleaner and eliminate the usual problems that a lot of people have.

https://documents.holley.com/frm36866.pdf

Apparently it also works on Sniper 1.
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Completely agree with this suggestion. Wish it was available in 2019 when I first made the switch, would have made my life much easier.

I actually bought one recently to use with a Terminator X system but for various reasons it’s not compatible. I’d be willing to sell it if someone wants it.
 
There are several ways to accomplish a steady supply of fuel for EFI - and incidently, they can also help with the issue you mentioned about fuel delivery taking too long with a carb. Just a matter of what you set the fuel pressure at. All require adding a return line. I have used all these approaches on one project or another.

1. Lazy option - just stick an inline pump on the existing system. These sometimes have issues on the suction side and will have issues with fuel slosh leaving the pick up uncovered. I have not used Hydramat; it's supposed to work well on slosh issues but costs a lot.

2. Stick an in tank fuel pump on the end of your sending unit. Helps avoid suction issues but still has slosh issues.

3. Surge tank. Less slosh issues but you have the expense and complexity of two fuel pumps.

4. Weld an external sump on the fuel tank with a nearby external pump. This is what I have now. Simple and the main downside is a little less ground clearance. I didn't use an expensive aftermarket sump kit - I welded a cake pan to the fuel tank.
 
After having done it, the only way I’d go would be a retrofit EFI fuel tank with an in-tank pump. The pump stays cool when submerged in fuel, it’s 10x as quiet and basically transfers little to no vibration through the chassis. Set it and forget it.

I get it though, this stuff is not cheap especially when you start adding up the plumbing pieces. These days an EFI ready replacement fuel tank and pump combo with all the trimmings will set you back a bunch but IMO it’s a worthwhile expense.

There are retrofit pump modules available now that install like the OE sending unit/pickup. That’s an easy and less expensive option though you wouldn’t have the benefit of having baffles inside the tank to keep the pickup submerged. Ultimately that could turn out to be a real PITA since you’d constantly have to be aware of how much fuel is in the tank to prevent uncovering the pick up.

This is the problem with all the ‘plug and play’ advertising. Will it work with minimal effort and investment? To a point, sure. Will it perform as well? Ehhh, not really. And when I say perform, I don’t necessarily mean peak power but rather the frustration vs. enjoyment quotient. It’s the same when you cut corners on anything.

Holley wants to sell products to everyone so they accommodate several levels of investment but the reality is that these systems work best when you use all the components they were designed around.
 
I have the retrofit module that Holley sells to replace the stock sending unit. Maybe it's the special absorbent sock they use or the pickup, or maybe it's because I always run on the top 3/4s of the tank in every vehicle I own, but I have never had trouble with the pickup losing suction. I drag race and street drive my car.

Cley
 
Clelan said:
maybe it's because I always run on the top 3/4s of the tank in every vehicle I own
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Exactly. Not a huge deal but just something to be aware of.

I regularly drove my Sniper-equipped Dodge on longer trips so it wouldn’t have been practical to stop every 30 miles to top off the tank. I was able to run it down to 1/4 tank but just had to be aware of inclines when it was that low.

All good, just pointing out the details you might not think about before buying this stuff.
 
Here is another gas tank idea. I bought a Gen5 Camaro pump with the basket and welded the top of GTO tank into a new A-Body tank.

The GM pump works like a surge tank in that it has a basket that surrounds the pump and a suction nozzle that fills the basket. In theory, shouldn't have any issues with slosh even at almost empty as the suction pump side of the setup keeps the basket overflowing with fuel.

Only downside I see is that I lost a little fuel capacity.

And it is untested as I still haven't installed it and used it. I am working on my G3 swap finally so maybe next summer?

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I'm telling you. tanks inc is the way to go. its new. no way am i going efi with a used tank. seen too many clogged injectors caused by a used tank. it comes powder coated, has a well that the pump sits in so there are no worries of running the fuel low in the tank. you can get an entire kit too that includes the tank,straps, pump and sending unit.

Mopar Fuel Tanks


few pics from my 70 dart tank. hard to see but there is a pocket made to keep the tank flooded.

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Just me but I think that while the Tanks Inc "baffles" are better than an open tank for sure, I don't think they are the best. How is the well filled in the Tanks Inc setup?

I much prefer the syphon setup of the GM bucket that keeps the bucket full at the same time it is supplying fuel to the engine. You could have a 1/4" of gas sloshing around the bottom of the tank but the GM fuel module bucket would be overflowing with fuel.

Here is an article on it - Fuel Modules - VaporWorx

And a visual:

 
Agree with Joe, the Tanks, Inc. ones are a really nice deal. I bought their tank and pump in kit form for my '68 Coronet, it was great. It came with a 255lph pump which was plenty for my application. They offer a larger capacity pump if needed but you'd have to be making some power to necessitate that. The EFI tanks by themselves are still under $300 and the 255lph pump is around $210. They also had brand new tank straps for like $15. have to get a sending unit too but they're not much. They also now offer floatless senders which are pretty cool but they are a bit more than the conventional ones.

The plumbing is where it starts to add up. As I've said previously, I use -AN fittings exclusively which add up quick but frankly I wouldn't use anything else. I have a surplus of them now but the initial investment can be eye opening, especially when you start getting into unusual adapters.

The one issue I can think of with the drop-in fuel pump modules is the plumbing and only in regards to accessing the top of the module. Once the tank is in, it can be difficult to deal with if/when you need to get at it since it's up against the trunk pan. I made short lines that connected to junctions just off the output ports so I could drop the tank without having to get at stuff that's hard to reach. Same with the wiring.

The baffles in the Tanks, Inc. tanks are fine. Again, I often drove the car until the fuel level was 1/4 full or less and never really had an issue. As long as you measure the pickup tube of the pump module correctly and ensure it sits on the bottom of the tank it should in theory always be submerged. If you run it low enough where it's not then that's really on you. A sump isn't really even necessary.
 
My question is how much does the in tank pump heat the fuel?

If the fuel is cooling the pump then it has to increase the fuel temperature. How much and how long it takes is also a question.

In my head, the temperature increase would be at low load, long duration driving where the pump is bypassing fuel at its highest rate.

I could be wrong but maybe someone has tested for that.
 
Newbomb Turk said:
My question is how much does the in tank pump heat the fuel?

If the fuel is cooling the pump then it has to increase the fuel temperature. How much and how long it takes is also a question.

In my head, the temperature increase would be at low load, long duration driving where the pump is bypassing fuel at its highest rate.

I could be wrong but maybe someone has tested for that.
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No clue but form my experience it's really not an issue in regards to any noticeable loss of performance or starting problems. Nothing like vapor lock...

All OEs use in-tank pumps now so if heated fuel was a real concern for that application we'd be talking about something else here. Higher capacity pumps and/or operating them at lower fill levels will increase fuel temps for sure but so will higher ambient temps. Nothing is perfect.

Obviously any tank needs to be properly vented but that's the same for any fuel system. Just don't fill the tank up to the very top on warmer days so it has some room to expand or it will puke out the vent.
 
Newbomb Turk said:
My question is how much does the in tank pump heat the fuel?
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I don't think the pump would heat the fuel any more than the natural ambient temperature outside the car would - and heat reflection off the road or carparks....that heats the fuel up.

I went with a custom-made aluminium tank complete with internal baffles to prevent weight shift when cornering. The guys who made my tank make tanks all the time for high-dollar pleasure boats and yachts etc. Pressure tested, and running the Holley in-tank pump now....has a drain section for emptying out if necessary. Running all AN fittings and braided hose. I'm not chancing anything to barb fittings and rubber hose with 58.5 lbs of pressure constantly flowing.

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