Holley Sniper EFI
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Joined: Jun 2019
Posts: 22
Holley Sniper EFI
Anybody run the Holley Sniper EFI in this group? Any good things to say? Improvement on acceleration? Problems, issues with timing? Thinking about putting it on my 72 Cutlass Supreme Rocket 350. Replacement for my Quadrajet. Will it bolt on my stock 4bbl manifold?
Thank you!
Thank you!
Last edited by Neuby7297; Sep 7, 2022 at 05:00 AM.
Registered User
Joined: Aug 2018
Posts: 406
From: Colorado
Anybody run the Holley Sniper EFI in this group? Any good things to say? Improvement on acceleration? Problems, issues with timing? Thinking about putting it on my 72 Cutlass Supreme Rocket 350. Replacement for my Quadrajet. Will it bolt on my stock 4bbl manifold?
Thank you!
Thank you!
https://classicoldsmobile.com/forums...sniper-162811/
Registered User
Joined: Jul 2009
Posts: 3,217
From: St Augustine
The Sniper is not a true plug & play (applies to all retrofit EFI units), checkout the Holley
Forum, plenty of factual info.
Some guys have no issues with their installs, others throw ‘‘em away, if your engine runs good…..
I’ve spent a year on and off, sent my Sniper back to Holley twice, etc..
Do your due diligence, then decide.
Forum, plenty of factual info.
Some guys have no issues with their installs, others throw ‘‘em away, if your engine runs good…..
I’ve spent a year on and off, sent my Sniper back to Holley twice, etc..
Do your due diligence, then decide.
Barely Registered
Joined: Feb 2014
Posts: 2,650
From: Gillespie County, Republic of Texas
Standard carbs usually give best power because they normally run rich. If an injection carb like the Holley gives any improvement, it will be only a few percent--you will not feel it.
If you get it running correctly, there are plenty of advantages, but extra power is not one of them.
Here's what some miss who have operational problems...
If you get it running correctly, there are plenty of advantages, but extra power is not one of them.
Here's what some miss who have operational problems...
- Holley ground and power must go directly to the battery terminals
- Open the hood on a dark night and, with the engine running, if you see a light-show, change ignition wires (regardless of whether your wires are the best super-zoomy brand available).
Registered User
Joined: Jul 2009
Posts: 3,192
From: Dallas-Fort Worth
The Sniper is not a true plug & play (applies to all retrofit EFI units), checkout the Holley
Forum, plenty of factual info.
Some guys have no issues with their installs, others throw ‘‘em away, if your engine runs good…..
I’ve spent a year on and off, sent my Sniper back to Holley twice, etc..
Do your due diligence, then decide.
Forum, plenty of factual info.
Some guys have no issues with their installs, others throw ‘‘em away, if your engine runs good…..
I’ve spent a year on and off, sent my Sniper back to Holley twice, etc..
Do your due diligence, then decide.
Registered User
Joined: Jan 2010
Posts: 6,120
From: central Indiana
Oh boy, get the popcorn ready!
If you absolutely have to have EFI, bite the bullet and spend the money on the Teeminator or dominator EFI system.
I have a Sniper on my car, and when it’s good it’s great. When it’s not, it’s REALLY bad. I’m guesstimating I have put 13k miles on the car since the EFI conversion
The problem is the lack of user serviceable parts. The ECM, IAT and MAP sensor are part of the throttle body and can’t be serviced independently. Failure of any requires throttle body replacement.
Im on throttle body number 3 on my car, all due to failures or poor manufacturing. I’m also on fuel pump number 2, due to the aforementioned lousy quality control in manufacturing. While I will give Holley credit for throttle body warranty, the hassle of having the car down sucks.
Holley definitely went CHEAP with some of the components and manufacturing practices. They got cheap with the injector connectors. I don’t think the supplied TPS and O2 sensors are top quality. Why holley chose to change throttle linkage designs (granted, they do offer and extension bracket or you can easily fabricate one to eliminate the touchy stuff throttle) instead of keeping the linkage that’s been used on every aftermarket Holley carb since the 60s is beyond me.
I attempted to drive my car to the Olds National meet in Murfreesboro last year, I got within 40 miles when the Holley distributor failed. It cost me 800 bucks for a Uhaul and trailer to get the car home. Once gain, Holley did step up to the plate and replace the distributor, and my insurance reimbursed me for most of the tow, but it was a major inconvenience.
Spend some time on the Holley sniper forum of Facebook group, you will see the same complaints. Seriously, as long as Holley has been manufacturing components for the OEM, there is ZERO reason for the lack of positive locking connector plugs. I recently had to install heat shrink on a injector because the plug had fallen off. Easy fix, but something that shouldn’t happen.
Regardless of what the EFI chest thumpers say, unless the engine is way out of tune, there won’t be a huge improvement in economy or performance by switching to EFI. In my case, the economy is about the same. It took over a year of fiddling to equal the quarter mile times I had with the Q-Jet. The sniper is advertised as self tuning, that’s a bit misleading. While entering basic parameters will get the car running, to get the most out of it will require professional tuning. In my case, after tuning the car on a dyno, I was finally able to equal the previous track performance.
None of this is new, I have several threads over the past couple years discussing all this so there is little point in going into detail again.
In all honesty, given the opportunity I’m not entirely sure if I would do it again. The biggest advantage of the EFI is the instant starts, regardless of how long it sits. My wife and I have been married almost 18 years, and in that time she has never mastered the ability to start a carbureted car. However, that’s not enough of an advantage to offset the worry that I’m going to get where I want to go.
If you absolutely have to have EFI, bite the bullet and spend the money on the Teeminator or dominator EFI system.
I have a Sniper on my car, and when it’s good it’s great. When it’s not, it’s REALLY bad. I’m guesstimating I have put 13k miles on the car since the EFI conversion
The problem is the lack of user serviceable parts. The ECM, IAT and MAP sensor are part of the throttle body and can’t be serviced independently. Failure of any requires throttle body replacement.
Im on throttle body number 3 on my car, all due to failures or poor manufacturing. I’m also on fuel pump number 2, due to the aforementioned lousy quality control in manufacturing. While I will give Holley credit for throttle body warranty, the hassle of having the car down sucks.
Holley definitely went CHEAP with some of the components and manufacturing practices. They got cheap with the injector connectors. I don’t think the supplied TPS and O2 sensors are top quality. Why holley chose to change throttle linkage designs (granted, they do offer and extension bracket or you can easily fabricate one to eliminate the touchy stuff throttle) instead of keeping the linkage that’s been used on every aftermarket Holley carb since the 60s is beyond me.
I attempted to drive my car to the Olds National meet in Murfreesboro last year, I got within 40 miles when the Holley distributor failed. It cost me 800 bucks for a Uhaul and trailer to get the car home. Once gain, Holley did step up to the plate and replace the distributor, and my insurance reimbursed me for most of the tow, but it was a major inconvenience.
Spend some time on the Holley sniper forum of Facebook group, you will see the same complaints. Seriously, as long as Holley has been manufacturing components for the OEM, there is ZERO reason for the lack of positive locking connector plugs. I recently had to install heat shrink on a injector because the plug had fallen off. Easy fix, but something that shouldn’t happen.
Regardless of what the EFI chest thumpers say, unless the engine is way out of tune, there won’t be a huge improvement in economy or performance by switching to EFI. In my case, the economy is about the same. It took over a year of fiddling to equal the quarter mile times I had with the Q-Jet. The sniper is advertised as self tuning, that’s a bit misleading. While entering basic parameters will get the car running, to get the most out of it will require professional tuning. In my case, after tuning the car on a dyno, I was finally able to equal the previous track performance.
None of this is new, I have several threads over the past couple years discussing all this so there is little point in going into detail again.
In all honesty, given the opportunity I’m not entirely sure if I would do it again. The biggest advantage of the EFI is the instant starts, regardless of how long it sits. My wife and I have been married almost 18 years, and in that time she has never mastered the ability to start a carbureted car. However, that’s not enough of an advantage to offset the worry that I’m going to get where I want to go.
Registered User
Joined: Aug 2011
Posts: 354
Pretty well covered with the other replies. I'll add a few thoughts though. First, I had a newly rebuilt engine, a completely new fuel system, plus the Sniper and Dual Sync distributor and the associated wiring. Even with all of the potential failures, the first start took one turn of the key and it roared to life. I've had no issues with hesitations or stumbles or surging, or any other issues with how it runs, save for some part throttle detonation. Fortunately, I can fine tune and tweak the fuel or spark in specific areas without having to change the entire curve. So looking at logs, I can pinpoint where the issue is and correct it in that spot.
BUT, as others have alluded, they're not bulletproof. EMI is a massive issue with these, and you'd better be sure your wiring is done right. I was stranded about 100 yards down the hill from my house because of EMI issues, and the damned thing would not run long enough to get me home. Even a poorly running carb will usually get you home. As also mentioned, it isn't really serviceable. Some people have zip-tied some close-enough injectors to get themselves home, but that isn't a great solution.
If I had known then what I know now, I would have bought a terminator/dominator setup. From all I've seen, they're far more robust, and serviceable.
That said, the car does run good with the Sniper, and I have no plans to go back to a carb.
BUT, as others have alluded, they're not bulletproof. EMI is a massive issue with these, and you'd better be sure your wiring is done right. I was stranded about 100 yards down the hill from my house because of EMI issues, and the damned thing would not run long enough to get me home. Even a poorly running carb will usually get you home. As also mentioned, it isn't really serviceable. Some people have zip-tied some close-enough injectors to get themselves home, but that isn't a great solution.
If I had known then what I know now, I would have bought a terminator/dominator setup. From all I've seen, they're far more robust, and serviceable.
That said, the car does run good with the Sniper, and I have no plans to go back to a carb.
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