Converting 8 Stack EFI to Holley ECU

Can I have more pictures? Not that I have a word of help to provide, but geez does that look cool...

In case you might be interested.

Holley Terminator X ECM: Mark Bailey still has a brand new (not used!) Holley Electronic
Control Module for sale. The new cost was over $1000; the current cost is (gulp) negotiable.
It turns out his setup required the MAX X instead of the plain old X.

Mark Bailey
(669) 333-2544
MarkPantera73@gmail.com

Steve, I had a customer with the same TWM FI hardware and ECU in a Pantera.

That Haltech ECU is only a 8 bit based microprocessor and peripherals ... barely able to support the engine especially at high RPM.

I replaced the ECU and added the plenum and MAP sensor the difference was a considerable improvement without changing injectors or any other engine components.

Thanks Jon.  How did you add the plenum lines?  Below the butterflies they drilled and tapped each of my throttle bodies for the nitrous and it looks like they plumbed it with SS brake lines.

Thanks Forest.  Do you know why Mark had to upgrade to Max?

Steve, PM me directly for more info.

Thanks,  Jon

Steve, I completely agree with your thought process. Lose the NOS and the Haltech ECU. The car will be much more drivable with the Holley ECU. Adding a MAP sensor is pretty easy. You need a MAP sensor plenum, MAP sensor, fittings and hoses. Rubber hoses are fine. IPSCO used to make a nice MAP sensor plenum. It’s one of those items that was never on their web site. The Holley ECU also needs both a Cam Sync and Crank signal, either from a dual sync distributor or a separate cam synchronizer and crank trigger (which would require distributorless ignition). The latter is better but more work and $. It may also require different TPS and CLT sensors. Maybe a different O2 sensor too. I assume the car gets vacuum for the brake booster from an electric vacuum pump.

Maybe Mark Bailey needed Drive-by-Wire!

Good luck !

Yes, he had to change due to having a drive by wire situation with the LS engine.

There has been significant development in aftermarket EFI kits since the "Blue Pantera" was built.

The Holley Terminator is Holley's solution. Edelbrock has one also called the FAST system.

I have the same eight stack system being talked about here and I am using the FAST. It is self learning. Plug and Play. It is about as simple and uncomplicated as these aftermarket systems are about ever to be.

You can easily go into the software charts and change the parameters but it isn't necessary. The software is already set to modify itself to achieve specific a/f points that have been dyno proven. You can change them if you want but so far from what I am seeing, it isn't necessary.

The set data is smarter then you are and the cpu is a lot faster at making the right changes then you can.

Also, FAST (Edelbrock) was wise enough to use very common (and inexpensive to replace) sensors in their system. That is a big plus for maintenance costs and longevity of availability of those components. There are no components shared with NASA, Ferrari, Porsche or Lamborghini. Just plain Jane GM production vehicles that will have service parts around for some time to come.

The FAST does use a MAP sensor to measure engine load. So it needs a common plenum chamber with all eight throttle throats plumbed to it, in a manner as if you were plumbing in a vacuum gauge.

Essentially that is what the MAP sensor is doing. Reading engine vacuum.

It should also be pointed out at this point, that the "vacuum gauge plumbing" does not need to be plumbed individually, each runner with a separate tube to the common vacuum box that you use. It works fine being plumbed in series, i.e., like Christmas Tree light wiring. Each line plugged into the other. That makes it much easier and cleaner to do on any car, particularly on a Pantera.

Theoretically, that Haltech is kind of obsolete now. It had to be programmed with a lap top for virtually everything.

It's main advantage at the time was thought to be that it fires the fuel injectors individually like an original equipment efi system does on a new vehicle.

For aftermarket uses, that is really not necessary and over complicates the programming unnecessarily.

FAST uses a batch fire system. It fires four fuel injectors at a time x 2.

The only disadvantage to that, if it is a disadvantage, is that for emissions reasons, you will have a minutely dirtier exhaust test.

That is because for a microsecond, there is unburned fuel laying on three other intake valves which haven't opened on the intake stroke yet and that unburned fuel can migrate to the exhaust valve in certain cam timing sequences.

So, therefore, individually fired fuel injectors are cleaner at idle and with US Emission standards, new vehicle manufacturers need every advantage they can get. That is why all OEM fuel injection systems fire the fuel injectors individually instead of in batches.

On a vehicle like the Pantera that is way over 20 years old, in the US, that simply isn't necessary. Batch fire is absolutely fine and as I see it, preferable?

The batch fire system that FAST adopted was actually designed by Bosch. It isn't a haphazard design. Just not optimal for new vehicles with strictly controlled exhaust emission requirements.

Performance wise, i.e., maximum power/go fast, there is no difference between individually fired and batch fired systems. At some point around 3,000 engine rpm's the individually fired fuel injectors can not keep up and start to work as a batch fire system.

So really those are the differences in the two available aftermarket EFI designed systems right now.

I have heard from certain self qualifying experts that they wouldn't be caught dead using a batch fire simply because it is the older design and not sophisticated enough for them to put their stamp of approval on it. So be it.

I don't argue. NO ONE is perfect! I realize that even if they don't. Sometimes very "bright" people can be very difficult to live with. I try to give them space.

The fact of the matter is that all things being equal, the simpler system by definition has to be better.

Anyway, that's what I know about what is going on with converting to EFI INDIVDUAL RUNNER aftermarket right now for whatever that is worth.

Again, the technology has just changed significantly within the last few years and those old systems like the Haltec are now just historical markers in the progression of better technology.

I'm just trying to help and sometimes the simplest things need to be stated. I'm not highly intelligent, just highly experienced.

Doug, that's very helpful about plumbing for the map sensor.  Can you post a photo of your plumbing?

Holley supports IAC (Idle Air Control).  It requires plumbing similar to what MAP needs.  It needs to be separate from MAP.  My understanding is that Holley can work without IAC.  I am trying to figure out if it is worth pursuing.

Steve, here's a photo of my MAP sensor housing. If you wanted to use an IAC, you could use two of them; one for a MAP sensor and one for an IAC. You have two fittings per runner already drilled, so it would be pretty easy. I did not use an IAC since my throttle was controlled by a DBW motor.

Ah. What I did?

My solution evolved from using the Weber 48 ida carbs.

I drilled and tapped into the carb mounting flanges. On the Hall manifold, they are very thick. I threaded in a -3 JIC male to 1/8"NPT adapter. Then used a -3 JIC T fitting running 3/16" stainless brake tubing from port to port. Flared tubing ends with tubing nuts and ferrels.

At the time there was a Mr.Gasket fuel log that fit in nicely just at the back of the intake manifold, near the top of the bell housing. There is a picture here of it installed that I included but you really can't see much of it, but that was my thinking, i.e., to minimize everything.

I ran the left side tubing to the left end of the log. The right side to the right side of the log.

This gave me four 3/8npt ports on top to use as vacuum accessory connections. I tried to use it as a vacuum source for the power brake booster but the IR system doesn't produce enough volume of vacuum for the brakes, but it is fine for a vacuum gauge and now is used also for the MAP sensor.

I'm using a Compcams vacuum pump for the brakes so there is no issue with not enough vacuum now.

On my set up, David's vacuum block would be in the way of my throttle linkage and using the Hall Pantera intake manifold, it has a cast in throttle tower for the throttle pivot.

It looks like you are likely already comited to using the ports drilled into your intake for the NOS but you can eliminate the vacuum block and gain some much needed room?

Here are some pictures. The top view is of the original setup with the Webers which I replaced with the throttle bodies. The vacuum plumbing is still there. The throttle connections are essentially still the same.

You can see a portion of the vacuum tube plumbing with the t-fittings which will give you a pretty good idea what they all look like.

The large -10 Hoses in the view from the top picture were removed. Those were initially intended for vacuum for the power brakes but that didn't work out.

The thought on the top picture was never to illustrate the vacuum plumbing. The combination of all of these pictures should give you an idea of how I try to tuck everything in.

The pictures would suggest that there is miles of space to work in and run hose and tubing, which really is the farthest thing from the truth in actuality?

I hope some of this helps?

With the FAST system, the CPU automatically compensates for the A/C compressor running and raises the idle speed, so with it I don't need an idle air control system separately. The combination of the sensors tell the CPU that the A/C is on and to raise the rpm. I think the number is it raises it 75rpm? Offhand I forget the exact compensation, but it works and it is adequate, and one less additional device to add onto something there is no space left for?

That's fine by me.

Thanks Doug.  The photos and your descriptions are very helpful.  As you mentioned the nitrous plumbing has already provided vacuum ports for both MAP and IAC.  Therefor I might as well setup both since Holley supports them.  In fact, the Holley setup wizard says that IAC is required although I can also see that it can be disabled.  

Pre Drive-by-wire, I mounted my throttle bellcrank on top of an IPSCO vacuum/MAP sensor housing. For a throttle return spring, I used a clock spring mounted on the underside of the bellcrank. You can see it in one of the attached photos. Most two bbl throttle bodies, including TWM, have a single common vacuum port, which is why I only needed four fittings on the housing.

When I started down this road (some may describe it as a rabbit hole) there was for practical purposes only the Hall manifold available.

Much of the plumbing choices were because of the idiosyncrasies of the manifold.

What you see is ultimately my solution for the Pantera. I had the same Weber setup on my 68 GT350 and everything was different.

The manifold that David is using changes it all again.

Incidentally, I still consider this all fun and not a burden as some would suggest.

I have been working with Jon Haas offline and he said that using soft plumbing to the MAP sensor is helpful because it dampens energy pulses from the intake.  Thus, I may try using 3/16 rubber vacuum line connected to a fitting like the one pictured above.  The runners on my manifold are already drilled and tapped for nitrous and the fitting might simply screw in.  The lines would tee towards the firewall.  The Holley ECU has the MAP sensor built in and the combined vacuum line would extend and attach to it.

Steve, please consult with Holley but I'm quite sure they will tell you, the hoses from the eight runners must all terminate in a common plenum. This is to absorb the pulses from individual cylinders. A MAP sensor doesn't work properly if the signal pulses. Rubber hose alone won't be enough. An IR intake is a very different animal from a single plenum type of intake. How large that plenum needs to be is a topic of debate. You saw the size of mine. The IPSCO one is 3 x the size. The one Borla casts into the base of their manifolds is 10 x the size but you can run MAP and IAC in the same plenum. Here's a photo of an Inglese plenum on a Hall Pantera manifold. I'm also told, the hoses from the port to the plenum should be as short as possible, so a remote plenum isn't a good idea. The theory is, you want the vacuum signal reaching the MAP sensor to be responsive yet pulse free. I know; sounds impossible! Oh, and the hoses should be the same length. Prior to my Holley Dominator ECU, I had an Accel Gen 7 and Accel told me I needed a plenum with a one liter capacity. I ignored that recommendation but it appears Inglese did not! 

@stevebuchanan posted:

I have been working with Jon Haas offline and he said that using soft plumbing to the MAP sensor is helpful because it dampens energy pulses from the intake.  Thus, I may try using 3/16 rubber vacuum line connected to a fitting like the one pictured above.  The runners on my manifold are already drilled and tapped for nitrous and the fitting might simply screw in.  The lines would tee towards the firewall.  The Holley ECU has the MAP sensor built in and the combined vacuum line would extend and attach to it.

If I went with IAC, it could be plumbed the same way and not difficult to try it.  Since the air (controlled vacuum leak) provided by the remote IAC is not affected by pulsing, I could make it with hard brake line.

I found a place to mount the CPU right over Jon's Ignition Controller on the firewall.

I personally think that there is a degree of experimentation with all of this? Just finding places to mount things alone can be a challenge and keep in mind that you want to be able to access or service these parts as easily and simply as possible.

Lots of things want to occupy the same space.

I think that all you need to do with the MAP connection is connect it just like you would a vacuum gauge. What it is doing is telling the CPU electronically what a vacuum gauge is telling you. That part isn't rocket science.

Mine wound up with a rubber hose to run the connection to the back of the engine where my vacuum manifold is. For me, these were the best locations for all considerations.

It is up to the software in the CPU to interpret what the engine needs and is doing. Not you.

It is the interaction of the various sensors and the software of them to make the instant changes. That's what the software is all about.

The software for an 8 stack IR system is a different program then a single 4v plenum intake.

You cannot make an 8 stack IR manifold work the same way as a single plenum intake. Adding huge plenums is attempting to turn the IR into a single plenum manifold. It can be done, but what is the point? Then it is no longer an IR manifold?

Thanks David and Doug.  I spoke with Holley tech support this morning and he said to make a plenum to help dampen the energy pulses for the MAP sensor.  For IAC he said there is no similar need and it can be plumbed in series.  He said to definitely utilize IAC.  I placed an order for the Terminator X, Dual Sync distributor, remote IAC, MAT (manifold air temp) sensor, cable from ECU to Windows tablet, etc.  

Holley EFI has an excellent tech support web site with many, many users. It's structured as a Forum, just like this site. Holley tech's keep an eye on it and jump in frequently. You can find answers to just about any question you might have. In fact, it's frequently quicker to post a question there and wait for a response, than it is to call Tech support. 

@davidnunn posted:

Steve, please consult with Holley but I'm quite sure they will tell you, the hoses from the eight runners must all terminate in a common plenum. This is to absorb the pulses from individual cylinders. A MAP sensor doesn't work properly if the signal pulses. Rubber hose alone won't be enough. An IR intake is a very different animal from a single plenum type of intake. How large that plenum needs to be is a topic of debate. You saw the size of mine. The IPSCO one is 3 x the size. The one Borla casts into the base of their manifolds is 10 x the size but you can run MAP and IAC in the same plenum. Here's a photo of an Inglese plenum on a Hall Pantera manifold. I'm also told, the hoses from the port to the plenum should be as short as possible, so a remote plenum isn't a good idea. The theory is, you want the vacuum signal reaching the MAP sensor to be responsive yet pulse free. I know; sounds impossible! Oh, and the hoses should be the same length. Prior to my Holley Dominator ECU, I had an Accel Gen 7 and Accel told me I needed a plenum with a one liter capacity. I ignored that recommendation but it appears Inglese did not!

David, do you know which material was used for the black flex lines above?  Is it silicone vacuum line?  I tried to use polyurethane vacuum line for my MAP and IAC plumbing and it melted once the engine warmed up.

Steve,

I used high temp plastic from McMaster Carr.

Thanks David.

I am probably going to re-plumb mine with 1/4" nickel-copper brake line.  I test fitted it with the push-to-connect fittings and it fits nicely, at least as good as the plastic tubing.  Time will tell if the plastic in the push-to-connect fittings melts as well.

Soft metal tubing, as you mentioned, is probably the easiest way to re-plumb this but -3 or -4 braided teflon hose will also work.

For vacuum it doesn't even need to be teflon lined and It doesn't need to be stainless steel since there is now black nylon braided hose.

The entire issue is going to be about serviceability. Often the solution is just ultimately to be determined by what you can fit and cannot. If it wasn't just for very little space, there would be no space at all.

How exactly did you get the linkage to fit and work after you took up all of the available space in the center valley?

I don't mean to bicker with the "Techs" on how you plumb the MAP sensor but the issue of the necessity of"dampening" the vacuum signal by creating a single plenum is questionable?

Data in our age is obtained by reading instrumentation. Maybe future Alien technology can change the physics but not now, not in this dimension of the Universe.

In this case, the MAP is reading engine load the same way that a vacuum gauge does. A vacuum gauge works on an IR manifold plumbed in series.

The way the EFI CPU uses that information may be the variation. Not how the information is obtained.

If there is issue with fluctuations in reading the vacuum it is with the specific MAP sensor that you use. You cannot change the outcome by creating a large plenum on an IR manifold. This is just not so. Believe what you want to. It won't change anything, just complicate the heck out of your plumbing.

Read your vacuum gauge plumbed in series. Is it smooth or is it vibrating? If the engine is firing correctly the gauge needle will be smooth, not vibrating. That won't change whether plumbed individually to a vacuum plenum or plumbed in series. That is exactly what the MAP sensor sees as well.

All a MAP sensor is, is an electronic vacuum gauge that translates the information into data that the CPU can read and apply to the interaction of the other menus such as rpm, throttle position, air temp, engine temp and air fuel ratio, interacting those menus together to adjust fuel delivery.

All that vacuum line plumbing changes nothing and as a result is for naught. You are just chasing a falsehood unnecessarily down a rabbit hole that will never end. The interaction of the software menus is what is going to compensate for anything.

It is called "self learning". If the CPU can't do that then replace it. It is outdated.

@panteradoug posted:

How exactly did you get the linkage to fit and work after you took up all of the available space in the center valley?

The flexible tubing is far below the throttle body linkage for the butterflies.  It is a birds nest in there but it does not conflict with other stuff.

I am running IAC (Idle Air Control) and I don't think others on this forum are using it.  It gets separate plumbing from the MAP in an effort to produce a more consistent MAP signal.  Today I re-plumbed the whole thing with temporary material so that I can test run the engine.  It is inexpensive polyethylene tubing from the hardware store and it works great.  The caveat is that I cannot run the engine for very long because it is only rated to 150 degrees and it will melt.

It looks like a possible material to use is called Viton Fluoroelastomer Tubing.  It will not melt like my polyurethane tubing did on the first try.  I read that it works with push to connect fittings.  Does anyone have experience with the Viton tubing?

My observation is that the issue is that an IR manifold does not produce enough VOLUME of vacuum. A single plenum like a single 4v does.

That simply cannot be compensated for.

So it is the sensors that need to be able to use/read the IR's inability to produce enough vacuum volume and a compensation made in the software for low vacuum. This isn't BS, it is just a different way of analyzing the data and making a correction/improvement.

Show me where an idle air compensator is needed please? I'm not comprehending that yet

The current EFI CPU's compensate for the load the A/C compressor puts on the engine automatically by design at idle and raise the idle rpm's when idling with A/C on. An automatic increase of 75 rpm is set as the standard in the program.

Consider the cam overlap when deciding to use IAC, there might not be much vacuum left. Even the PCV needs to be a low flow type to maintain enough vacuum.

There are other ways compensate idle speed, ALPHA-N adjustments are used with IDT.

This is my first 8 stack EFI.  I worked with Holley tech support to configure the system.  They recommended implementing IAC on my engine.  I think it helps with startup and it might help with a smoother idle.   Terminator X includes full support for IAC.  I think my cam makes sufficient vacuum for it.  There is no PCV or brake booster feed on my engine.

Also, it seems that my MAP signal is steady.  I will try to post the graph from a data log.  

An IAC (Idle Air Control) is just a controlled vacuum leak. When the throttles close, it opens and closes enough for the engine to idle at a specified RPM. An IAC usually gives a very smooth idle but works best in a plenum on the larger side.

For what it's worth, here are two screen shots of my engine's data log.  The royal blue line in the first screen shot is the MAP sensor.  It looks like the vacuum signal is fairly smooth and is good input for the ECU.  The second screen shot shows the IAC as the light blue line, and shows the the IAC opening and closing.

I don't see that as smooth at all. Smooth would be curved peaks and valleys like the surface of the ocean.

To me this indicates that the individual vacuum plumbing to a vacuum chamber is a waste of time and energy. Others may disagree and read it differently.

In order to really determine the overall effect you would need to graph the MAP without that added plumbing. That would be the only way to know for sure if and how much dampening effect it is having.

As a result, that graph isn't telling me much.

A friend of mine that was a VP of engineering at Subaru for decades looked at the data log and thought it was healthy.  He said the next step is to put it into closed loop/learn mode.

At this point it is easy to move the plumping around and I will try some other setups.

I came across a tubing material that seems appropriate for this setup:

High temp 1/4” Nylon PA6 tubing. 120*C /248*F.  Perfect for plumbing wastegates, blow off valves, fuel pressure reference lines.

https://lowdoller-motorsports....j05acTKEh-AXpevj8spA

I agree with the adage, "if it isn't broken, don't fix it". For sure things are complicated enough with the swap over to change an approach now.

Personally I feel "uncomfortable" with using any kind of a "plastic". I don't want to be the "guinea pig". I do understand the need for the flexibility in such a tight space though.

I have found on several occasions on my current Fords and Audi's those factory applied flexible plastic vacuum lines split and leaking for no other reason that they have aged.

That concerns me in that I want bullet proof materials as much as possible on that car. Those broken plastic vacuum lines must have been the best materials available at the time for a major manufacturer to use to begin with. Hopefully there are better materials then those available now?

Fixing something like that "on the road"  is likely as close to impossible as there might exist on a Pantera? That is "flatbed time".

I have seen several applications where Inglese just used regular old fashioned rubber vacuum hose for that plumbing. I don't know if that is still the situation since all of his builds are completely custom anyway.

Why don't you inquire with him on what to use for the vacuum plumbing?

@panteradoug posted:

I don't see that as smooth at all. Smooth would be curved peaks and valleys like the surface of the ocean.

Doug,  the reason it doesn't look smooth is because of the extremely high resolution of an IAC. I'm not sure of the exact specification but it can literally make "hundreds" of minute adjustments per second. If one could average all of those adjustments down to one per second, it would likely give you a basic waveform. The vast majority of modern production cars control idle speed with an IAC.

@davidnunn posted:

Doug,  the reason it doesn't look smooth is because of the extremely high resolution of an IAC. I'm not sure of the exact specification but it can literally make "hundreds" of minute adjustments per second. If one could average all of those adjustments down to one per second, it would likely give you a basic waveform. The vast majority of modern production cars control idle speed with an IAC.

The bottom line is that it runs fine. So I agree, leave it the eff alone! I am just stubborn and I want to see an over layed comparison of that graph with and without the added vacuum chamber. Data is difficult to argue with.

I would normally be one to head the warning of the "Tech's" but in this case where there is so little room to plumb much of anything on that manifold,  I would need additional justification to suffer that additional pain and anguish to  plumb it that way.

Incidentally, the workmanship is impressively excellent so that is not my criticism at all.

As far as needing IAC goes, the current FAST system that I am running doesn't need one. It compensates in the software. So what I am interpreting this as rightly or wrongly (which I too often am) is that "you guys" when you are upgrading are already upgrading to an older obsolete system.

Now in actuality, I often hide in my room and garage for weeks without speaking to anyone. Especially my wife since she sometimes hourly rates me by my mistakes and misjudgements. That also adds often to the general consensus  of "don't listen to him, he's a wacko!"

Is there such a thing as pre-dementia? You know, like pre-diabetes?
No one ever comes back and acknowledges when I was correct. They just go on like nothing ever happened, so I'm wonder about that now? I don't see it when I look in the mirror?