# Fuel injection? Sanity check



## 73Jim (Jul 17, 2021)

Hi all, 
I'm looking to replace my Edelbrock carburetor with a fuel injection setup. I think I'm down to the Holley Sniper 550 or the Edelbrock Pro Flo 4 and I would appreciate a sanity check. What I have accumulated so far:

Where they are similar

Both require 58 PSI fuel (fuel upgrades are common to both, thus eliminated from this discussion)
Both have one wideband o2 for closed loop operation
Both have dedicated forums for support
Both self learn (after time/temperature)
Holley 4 X 100lb/hr injectors. Edelbrock 8 X 35lb/hr injectors
Both can support boost (Holly 21PSI, Edelbrock 15PSI) for future power adder
Holley advantages

Can reuse my distributor/manifold (have to lock out advance)
Can data log to SD card (an engineer by trader so I LOVE data)
Can run deadhead fuel system (if I want to...)
Cost (Holley 1330/ Edelbrock 2165)
Edelbrock advantages

Multiport fuel injection (easier to upgrade for future power adders)
Can remove my MSD 6AL, cleaner engine bay
Included tablet or Android App. 
Can data log by CAN bus streaming (don't know if the tablet can log or need the laptop)
The car is a 71 Lemans with a 462, XE274 flat tappet cam, 9.5:1 compression with 6X-4 heads (94cc), 5 speed manual with a 3.42 rear axle ratio. I'm an electrical engineer so I understand closed loop systems (PID loops), fuel maps/AF ratios/injector PWM and did I mention I LOVE data?

Is the Edelbrock worth the 61% bump in price? I guess I could sell some of the take off parts to offset some of the cost...


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## GTO44 (Apr 11, 2016)

Those are both good systems. I prefer the Holley Sniper. It works great and retains the carb look with the air cleaner on. I also vastly prefer holley’s software vs anything else on the market. The pro flow has a specific look and thats usually why people get that system. Multi port fuel injection is a benefit over the sniper.

A couple notes.
The Sniper is 650hp capable for N/A or nitrous setups. To get the boost capability you either have to get the Super Sniper 650 (only $200 more) or the Super Sniper 1250 for big power. The Super Sniper 650 also gives you more inputs and outputs. You can add fuel pressure, trans temp, oil temp, dome pressure, ect. and data log it all.
You mentioned one of the benefits of the proflow is no more cdi ignition box. The sniper can also be run without a cdi box. They come with a “coil driver” for use with ignition control and no cdi box. Its very small and can go under the dash or hidden where ever.

I also prefer holley support and forums over the edelbrock.

Both systems are fantastic. Both will run your engine and setup much better than a carb. If you’ve never used either than you wont be partial to one software or another. I say get the one that fits the look your going for or the one that fits your budget.


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## 73Jim (Jul 17, 2021)

Yep, my bad, I was referencing the Super Sniper 650. Part #550-519

One thing I've noticed, none of these systems have knock sensors. There are water passages on the heads to insert knock sensors. Not ideal better than nothing. Anyone retrofit knock sensors?


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## Totimeout (Aug 5, 2021)

73Jim said:


> Yep, my bad, I was referencing the Super Sniper 650. Part #550-519
> 
> One thing I've noticed, none of these systems have knock sensors. There are water passages on the heads to insert knock sensors. Not ideal better than nothing. Anyone retrofit knock sensors?


The factory sets up the knock sensor on each engine from the vibrations the engine makes. Adds all the vibrations up, calls that zero and the knock sensor measures from there . You can't just stick a knock sensor in.


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## 73Jim (Jul 17, 2021)

It's just an offset. I can log data to get a baseline. Check my plugs and anything else to verify the absence of knocking, then use that baseline as a reference. 

I've used a stand alone MSD knock senor on an engine test stand I designed for work and that is the protocol I used. Figured it worked once....why not again?

It's the location of the sensor that is tricky. Should be in the center of the block X,Y and Z axis. Since that is not possible, I was hoping someone had an idea.


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## GTO44 (Apr 11, 2016)

73Jim said:


> It's just an offset. I can log data to get a baseline. Check my plugs and anything else to verify the absence of knocking, then use that baseline as a reference.
> 
> I've used a stand alone MSD knock senor on an engine test stand I designed for work and that is the protocol I used. Figured it worked once....why not again?
> 
> It's the location of the sensor that is tricky. Should be in the center of the block X,Y and Z axis. Since that is not possible, I was hoping someone had an idea.


The sniper does not have the ability to run knock sensor. You would need to step up to a Terminator X and go multiport fuel injection. IMO you dont need knock sensors. Plugs will tell you everything you need to know. Calibrating them in a custom application would be the most difficult part.


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## Atarchus (Aug 4, 2020)

I have the Pro Flo 4 on mine, one thing to remember when comparing is that the Pro Flo 4 also replaces your distributor and your timing is completely controlled via the ECU, which is a HUGE advantage IMO. I have no complaints, I love my PF4 system.

The PF4 has no data logging built in, which is stupid. But, there are several options out there to utilize the CAN bus. I purchased a Banks iDash gauge that I use to monitor any readouts I want on the fly, and it also has data logging built in. So, it accomplished both my goals of having a gauge to give me constant instant readouts without needing to use a tablet or my phone, and also data log. The CAN bus has power and ground built in, so the unit powers on/off with the key every time, it's a nice solution.

When comparing price, remember that the Edelbrock system comes with a new intake manifold, distributor and is a multiport EFI system.

_edit_
Also, if you get the Edelbrock system do yourself a favor and get the system without the tablet for $100 less. The tablet is garbage, and you can just use your phone anyway. If you really want a larger tablet, wait until black friday and get a decent tablet on sale for $100...


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## 73Jim (Jul 17, 2021)

Atarchus said:


> I have the Pro Flo 4 on mine, one thing to remember when comparing is that the Pro Flo 4 also replaces your distributor and your timing is completely controlled via the ECU, which is a HUGE advantage IMO. I have no complaints, I love my PF4 system.
> 
> The PF4 has no data logging built in, which is stupid. But, there are several options out there to utilize the CAN bus. I purchased a Banks iDash gauge that I use to monitor any readouts I want on the fly, and it also has data logging built in. So, it accomplished both my goals of having a gauge to give me constant instant readouts without needing to use a tablet or my phone, and also data log. The CAN bus has power and ground built in, so the unit powers on/off with the key every time, it's a nice solution.
> 
> ...


Do you have any issues with the air filter contacting the fuel rails? Do you use the pressure regulators that attach to the rails?


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## Atarchus (Aug 4, 2020)

73Jim said:


> Do you have any issues with the air filter contacting the fuel rails? Do you use the pressure regulators that attach to the rails?


Nope, no issues with the filter. I use a vacuum referenced pressure regulator that I mounted under the hood.


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