Holley EFI

[hinoonaz]

Revisiting going EFI from a Holley 650. It appears that there are two choices from Holley for a 347 with a lopey cam that likes 2000rpm and up for throttle response. Is vaccum a major factor in determining which EFI manufacturer to use or stay with what i have. Too much info and not enough knowledge to sift thru what works without days on dyno. Just trying to make up my mind. Our travels are between sea level to 7,000'. Thanks for advice, Gary

[mrmustang]

Most folks these days are headed towards the Holley Sniper EFI systems.

Bill S.

[eschaider]

Gary,

Lopey idles and vacuum considerations are meaningful considerations for carburetted engines. They make no difference for EFI. In fact the EFI will somewhat smooth out your loopy idle and improve low speed throttle response — although that may not be what you want.

What you want to do before spending money on EFI is to purchase some reading books on EFI systems, which means you will probably spend around $50 on various candidates. Get familiar with the capabilities of EFI systems and decide which capabilities are important to you. Next thing you want to do is hunt down EFI providers that offer those capabilities. Rank them according to cost and capability. Decide how much money you want to spend on the conversion. Pick the system that matches you list of important features and meets your budgetary goals.

One of the most important capabilities you will want is a Mass Air Flow (MAF) capability. There are three fueling models for EFI. Alpha-N, Speed Density, and Mass Air Flow. the only one that will allow you to move 7000 feet vertically and still properly fuel your engine, without retuning, is the MAF based system.

Most aftermarket systems are speed density. If you experience a 1500 foot or more change in altitude, a speed density system will benefit from being retuned. Speed density system providers will either suggest the difference is not worth retuning for or suggest the speed density logic can accommodate it. Both suggestions are wrong.

By the time you get to 3000 feet your engine will feel like it has lost considerable horsepower, partly because of thinner air and partly because of incorrect fueling at that altitude. At 7000 feet you will think you need a tow truck.

The other thing to be sensitive to is sensors. Most aftermarket suppliers like GM sensors. In fact they like them so much they repackage them in their own proprietary bubble packs and boxes and reprice them significantly above the over the counter equivalent GM sensor price point. You want to avoid these types of providers.

If you are electrically handy you will enjoy building you own wiring harness for an aftermarket system. If you are not this will be a royal PITA. Some EFI manufacturers will work with an OEM engine wiring harness saving you all the build effort. By work with, I mean they will plug right into the OEM under dash connector on the under dash harness that connects to the engine harness.

Holley does offer some EFI systems that can make use of selected OEM harnesses. You should look at them. You should also look at the DIY Autotune Plug and Play systems that plug into a stock Ford Mustang harness. DIY Autotune will be less expensive and come with a base tune to get you started. BTW they also support MAF based fueling and use Ford OEM sensors which you can buy directly from Ford.

Here s a link =>MS3Pro Plug and Play. Pick the Mustang ECU closest to what you are doing and the ECU for the year and engine harness you decide to use.

I forgot to mention if dashboard support is important to you they support many aftermarket dashes/displays such as Racepak, Race Technologies, AiM Sports, AEM, Dakota Digital, Autosports Labs, Perfect Tuning, and OEM Ford New Edge dashboards.

[twobjshelbys]

Originally Posted by eschaider

One of the most important capabilities you will want is a Mass Air Flow (MAF) capability. There are three fueling models for EFI. Alpha-N, Speed Density, and Mass Air Flow. the only one that will allow you to move 7000 feet vertically and still properly fuel your engine, without retuning, is the MAF based system.

To expand on a MAF system. If you don't use a MAF, and at least one O2 sensor, what you have done is changed the system to an electronic instead of mechanical carburetor. You have a huge expense at no gain over the mechanical system since the benefit of EFI is that it automatically compensates for atmospheric pressure. Yes, even local weather conditions but more importantly altitude changes. If you live at a constant altitude and don't have a MAF then the EFI system will perform no better than a propertly tuned carb and you will have spent a lot more money that you would have used to tune our carbs.

You'll also probably have additional expenses in fuel return lines and more likely than not upgraded fuel lines and fuel pump.

The truth is that unless you go from Phoenix to the mountains, and go there to race, the carbs adjusted for your altitude will perform well enough. Plus, unless you stop, it won't matter, since the MAF takes its initial altitude reading before the engine runs (it can't measure altitude once air flow starts.)

Chances are that if your carbs are properly tuned now, after the EFI conversion you'll wonder if it was worth the expense. Of course, if you've given up on badly tuned carbs a well adjusted EFI system will be a gain.

Lastly, if you are a tinkerer and this is a project to keep your hands busy then by all means go for it

This topic is probably the second-most new thread that has already had many many discussions already in the forum. In fact, you will find the same participants giving the same advice. Search can be your friend.

[eschaider]

If your EFI system has pre and post temperature and pressure sensors then the fueling depends on whether or not the sensors are continuously read or only initially read, as Tony has already said.

A Mass Air Flow sensor reads air mass continuously as the engine operates which gives you a huge advantage over speed density technology and allows you the freedom to go to high altitude like Denver or low altitude like Death Valley without the need to retune your engine. There is typically also an IAT1 (Intake Air Temperature pre-compressor) and sometimes an IAT2 sensor (Intake Air Temperature post-compressor) to map how much the blower heats the air (for proper fueling) but also for detonation control.

Hot intake charges are more susceptible to detonation than cool intake charges. If the ECU's software is smart enough to track the IAT2 temps it can be used to pull timing when IAT2 temps get too frisky. This becomes a big deal for blown gas engines. One of the most detonation sensitive fuels is nitromethane. For the proletariat enthusiast it is always good to know that gasoline is equally detonation sensitive in, yes, supercharged applications.

By now it should have popped up on most folks radar screens that blown gas needs good detonation detection and prevention system. Many but not all EFI systems provide some level of detonation detection. For the ones that do not (or do a poor job) there is an excellent detonation detection and prevention device available from J&S Electronics. It is called The Safeguard and it is available in three different configurations to handle distributor ignitions, smart coils (near or on plug) and dumb coils (near or on plug).

The J&S device will detect knock and then pull timing from just the cylinder than knocked and do it in real time before the next ignition event! there is absolutely nothing available from anywhere else that can do this today. The technology is relatively mature but because of complexity has never been commercially duplicated. It was developed over 40 years ago for turbo charged V6 Buick Regals. Even embedded EFI knock control logic does not perform this well!

This is a link to the J&S website where you can dig little deeper if you are so inclined, click here => J&S Electronics.

Do not get detonation detection and prevention confused with the blinking lights that flash when they think they see detonation. By the time you see the light and before you can react, the damage has already been done. The earliest detonation events are imperceptable to the human ear. You need technology to 'hear' them. Even more daunting the sonic signature of detonation can be elusive.

The J&S Safeguard System consistently catches all of it at inception and pulls timing before the next ignition event occurs. After the event the J&S technology begins to increase the timing at each ignition event until it 'hears' detonation again. When it does, it steps back from the brink and runs that one cylinder just shy of detonating. It does this in real time as the engine is running and for all eight cylinders independently.

[hinoonaz]

Thanks for the info all. This is why i asked for advice. I am most likely staying with my carb. Stumbles a little under 2000 rpm at times but goes strong. No choke contributes.
Great info Ed, Bill and Tony. What eye candy i would like is an 8 stack of webers.
Gary

[hinoonaz]

Thanks for the info all. This is why i asked for advice. I am most likely staying with my carb. Stumbles a little under 2000 rpm at times but goes strong. No choke contributes.
Great info Ed, Bill and Tony. What eye candy i would like is an 8 stack of webers.
Gary

[Roylerumble]

I think the biggest issue when moving towards Holley EFI is getting it. I ordered mine in February of last year, and still haven't received it, was "apparently" in stock when I ordered it, but low and behold it ended up backordered. Each month they extend the back order to the next.

[spdbrake]

Originally Posted by Roylerumble

I think the biggest issue when moving towards Holley EFI is getting it. I ordered mine in February of last year, and still haven't received it, was "apparently" in stock when I ordered it, but low and behold it ended up backordered. Each month they extend the back order to the next.

Which Holley EFI do you have on order?

[Bossbill]

If you call the Holley Tech Line they can give you a better idea.
The situation appears to be mostly a chip shortage. I ordered my Terminator X on 3/27/23 and received 6/23/23.

[mrmustang]

Originally Posted by Bossbill

If you call the Holley Tech Line they can give you a better idea.
The situation appears to be mostly a chip shortage. I ordered my Terminator X on 3/27/23 and received 6/23/23.

Since this thread is now 12+ months old, I suspect that the OP has already taken care of his issues.


Bill S.

[Bossbill]

Every forum has their rules about either adding on to existing threads (regardless of age) or always creating new threads.

Which is it here?

[eschaider]

I think common sense plays a significant role here.

If threads are 2, 3, 4, 5, or more years old, the original thread participants have long since moved on. Some original participants may no longer be active, some may have sold their rides (in the 5+ year window), and others may have even passed away!

For all intents and purposes, as of that last posting, the thread subject has been resolved to everyone's satisfaction or capability.

If you have what you believe to be significant new information on the subject matter, starting a new thread would be the right approach. If you have questions on the subject matter, start a new thread with your question. Resurrecting the old thread is probably not as good an idea.

[mrmustang]

Originally Posted by Bossbill

Every forum has their rules about either adding on to existing threads (regardless of age) or always creating new threads.

Which is it here?

There is a sticky I wrote for a sister forum to this one, then adopted here. It is above this thread towards the top of this subform marked as "Newbies read this" ,.

Hope you find it helpful.

Bill S.

[twobjshelbys]

There are some threads that can safely be resumed after a period of time. Starting new threads where an existing thread exists happens frequently. The result is a discontinuity of content and often repetitive content. It would be better to continue an old thread than to come into a new one and say "see thread x" it's already been discussed.

Regarding whether to kick an old thread it's a matter of whether the new content adds additional value. Simply adding a comment that says "I agree with that 5 year old post" adds nothing.

I believe that in the forums these days most people read by using the "new posts" button. So along the same thought, it's hardly ever necessary to post the same content twice in two different subforums as if one doesn't get ignored, you end up with content either duplicated or bifurcated...

[Joey.S]

Originally Posted by hinoonaz

Revisiting going EFI from a Holley 650. It appears that there are two choices from Holley for a 347 with a lopey cam that likes 2000rpm and up for throttle response. Is vaccum a major factor in determining which EFI manufacturer to use or stay with what i have. Too much info and not enough knowledge to sift thru what works without days on dyno. Just trying to make up my mind. Our travels are between sea level to 7,000'. Thanks for advice, Gary

Joey.S

[hauss]

I do not mind reading the old, with new. It saves me from jumping around. My neighbor tried, the holley sniper and finally got so frustrated with it, he packed it up and purchased a 650 holley carb, for his new build. I have also herd holley, has a new version. I could purchase it from him, for pennies on the dollar but, I like my 750 quickfuel most of the time.

[Tremelune]

Sooo, if I want to put a MAF EFI system on my small block Ford...What are my options?

And what are y'all doing for fuel return lines? Space is pretty tight on these things...

[Tremelune]

Sooo, if I want to put a MAF EFI system on my small block Ford...What are my options?

And what are y'all doing for fuel return lines? Space is pretty tight on these things...

[eschaider]

Many EFI providers support MAF-based fueling models, although they promote speed density. If you elect to go with a Mass Air Fueling model (which I would encourage), you need to get a good MAF.

This is a link to a MAF test that demonstrates the difference between a good MAF and a great MAF, click here => https://www.youtube.com/watch?v=DAYAT-zTTRI&t=27s

The smoother and more repeatable your MAF voltage signal (the electrical representation of the air mass consumed by your engine), the better the fueling job the ECU can do for you. In addition to a good MAF signal, you need a set of good injectors with the least variation from injector to injector across their operating range.

This goal is achieved by buying correctly flowed injectors. Many injector suppliers will flow your injectors at max flow and perhaps even attempt to swap a few in and out to get a similar max flow, but that is only a part of the proper flow testing and injector matching you need to do.

In Detroit, there is a firm called Calibrated Success. It was founded and is run by Greg Banish. For those of you old enough to remember (that should be more than a few of you reading this), there was a 1950s or 60s half-hour TV Western called Have Gun Will Travel the protagonist was a character name Pallidin. He was a gun for hire that the little guys could use to put bigger bad guys in their place.

Greg is a modern-day Fuel Injection Pallidin. He does contract EFI Calibration work for the Big Three in Detroit to help their vehicles meet EPA guidelines, and he also does performance EFI education for enthusiasts like us.

One of his beneficial services is an Injector Calibration service that goes light years beyond the typical aftermarket maximum flow matching. Click here => https://calibratedsuccess.com/fuel-injector-test-bench/.

You need the correct injector performance, just like getting the proper MAF performance. Greg is the Undisputed Heavy Weight Champion in this category. If anyone is going to the PRI show this week, he will be there, and you ought to make a point of stopping by to see him. You will not be disappointed!

Beyond the fueling model you choose, the MAF you choose, and the injector characterization you decide to use, there is an additional consideration: whether or not to run a return style or a returnless style fuel delivery. In a return-style system, a manifold pressure-referenced fuel pressure-relief allows you to set your base fuel system pressure. Base fuel system pressure is the pressure your EFI system expects to see across your injector.

The fuel pressure across the injector is what the ECU uses to calculate (along with some other stuff) the required injector pulse width to meet your commanded lambda target for the engine's operating environment. On a n/a engine, it is important because it produces a predictable, smooth, and consistent fuel delivery necessary for reliable and easy-to-drive engine operation. On a supercharged engine, especially a supercharged gasoline engine, this separates the burned pistons and engine rebuilds from the happy country drives.

Unlike the return-style fuel system that requires a fuel return line to the trunk, a returnless system has none. Instead, the returnless system has variable-speed turbine pumps that the ECU controls based on the sensor data it reads off the running engine. Returnless systems are elegant, complex, and sophisticated. Along with a Mass Air Fueling model, they are the only way Detroit can meet emissions and performance targets anywhere on earth without a retune.

The anywhere on earth without a retune should ring like a bell on a cold winter morning for those of you who go through more than 1000-foot changes in altitude. Tony (TWOBJSHELBYS) has an unusually colorful way of referring to the Speed Density style EFI systems. If I remember correctly, he calls them an electronic carburetor (If I misquoted you Tony, please correct me ), and that is exactly what they are.

If you have driven a carburetted Cobra to or from low to high altitude, the change in throttle response and engine torque are virtually identical with a Speed Density fueling model. The only difference is your wallet is lighter by whatever you paid for your system, but, and this is a biggie, it doesn't perform any better than your old carburetted engine!

EFI is a big step but done correctly with some patience and a measure twice cut once approach can be rewarding beyond your expectations — especially if you are supercharged or plan to be.