Preparation for Holley Terminator X install – Foxbody 306 (electrical fan, alternator, MSD Ignition, etc)

[So_Flo]

Hello everybody,

I’m looking for some insight and feedback on this Holly System for my 1988 5.0 Foxbody Mustang.

The car has a 306 with the aftermarket bolt-ons and some motor work (cam, intake manifold, larger injectors, headers etc.). It’s a weekend cruiser, not a drag car. Just want a stable idle and run well at this point.

I’ve already purchased a Holley Terminator X system.

However hesistant on moving forward. I have a few questions, but I’m open to all advice at this stage. If I’m missing anything important, please feel free to point it out.

1. Does anyone know of a reputable shop in South Florida that can wire and tune a Holley system? Ideally looking for someone with experience specifically with Foxbodies and Holley EFI.
2. Would it be worth converting to an electric fan setup (before Holly installation)? If so, what fan setups are you guys running or recommend?
3. Should I upgrade my alternator? The car currently has the stock 75 amp unit. The only added electrical load right now is a 12” subwoofer and HID headlights. If I upgrade, what amperage should I be looking at?
4. I picked up a used MSD 6AL (part #6420) ignition box. Would this benefit my setup, or is it unnecessary with the Terminator X?

For now, I plan on keeping the factory distributor and would prefer to avoid switching to a dual-sync distributor unless it’s really necessary to get the car running smoothly.

Appreciate any advice or recommendations. Thanks in advance.

 

[RaggedGT]

I don’t have much experience with the Holley stuff, I know @TOOLOW91 has installed many- @SorsCode does a lot with them as well. If they have time they may drop by

 

[SorsCode]

I don’t have much experience with the Holley stuff, I know @TOOLOW91 has installed many- @SorsCode does a lot with them as well. If they have time they may drop by

Thanks sir

OP: call the shop tomorrow and we can help you out on all of it. Website is www.mfkustoms.com you can grab our number from there.

To answer some of the questions:

1. Not sure, but the install is easy you could do it yourself. I even offer something that makes it dead simple.

2. That’s up to you. If you are fairly stock not really needed. It does clean the engine bay up though. Contour fans are a good option.

3. Yes, swap to a 3G setup

4. You can use it, but really need to understand your setup more.

Don’t go dual sync. TFI is more than good enough.

 

[General karthief]

2 questions and an opinion.....
Is the Holley system being considered because the engine don't run good?
Mass Air or speed density?
Installing aftermarket parts on an engine that runs poorly complicates (in most if not all) finding the issue.

 

[2000xp8]

Heads?

 

[So_Flo]

2 questions and an opinion.....
Is the Holley system being considered because the engine don't run good? I bought it thinking it would benefit my build. That due to the aftermarket parts on the car I would need a computer to tune it.
Mass Air or speed density? Speed density
Installing aftermarket parts on an engine that runs poorly complicates (in most if not all) finding the issue.

Sorry for the lack of detail , here’s a better breakdown of my setup and what I’m dealing with. see my first post , first post or see the last paragraph here.
The motor itself runs strong to my standards and pulls well, but I’m having a couple of issues where in hopes the Holly can fix or ease my problems.

• It's almost like it bogs/hesitates when I go wide open throttle at times.
• Idle is inconsistent
• RPM tends to hang and stay above 1,000 RPM

Parts Installed (As best as I can remember)

• 24LB injectors
• Adjustable FPR
• Cam: Mild E303 cam (by COMP)
• Headers: BBK equal-length shorty headers
• Intake manifold: Edelbrock Performer RPM II upper and lower
• Heads: Edelbrock Performer heads (Part #: 6025, CARB #: D-215-33 MAK 95)
• Pistons: Flat top pistons (brand/specs unknown)
• Rockers: Blue roller rockers
• 255 LPH Fuel Pump (Jegs)
• Throttle Body w/ spacer 70mm

 

[So_Flo]

Heads?

• Edelbrock performer.

Refer to my comment above for the breakdown.

 

[So_Flo]

1. Not sure, but the install is easy you could do it yourself. I even offer something that makes it dead simple.

2. That’s up to you. If you are fairly stock not really needed. It does clean the engine bay up though. Contour fans are a good option.

4. You can use it, but really need to understand your setup more.

1. I was thinking of doing it myself, but saw a couple of videos and got intimidated lol. I'm a novice when it comes to the electrical world.
2. I wouldn't say shes stock, but if its not to much trouble, can you refer to a brand or link of the contour fans?
3. 
   
4. The current setup should be mentioned above.

 

[bdub_mkg]

I installed a standalone efi system in my 69 vert w a 351w and a few other systems on other cars.
If youre going to efi, electric fans etc, make sure your alternator is up to par. Inconsistency in voltage will mess with your efi.
Also, any issues your motor is having such as vacuum leaks, will really come to light with efi so if youre having idle issues, you might want to get that checked and solved first.
Most of the efi kits out there will learn as you drive it so you shouldn't need a tuner unless you really are searching for something.
Make sure you have good grounds for all your wiring. Look up the big 3 for grounding cars.

 

[2000xp8]

That combination is nothing out of the ordinary.
Most likely there is something mechanically wrong with the car.
IMO, your solution to fix it is extreme and is going to leave you open to a whole slew of different issues compounding the problem.

How exactly are you running 24lb injectors without a meter?
I haven't seen that done in 20 years, it also requires a cam that is speed density friendly and since the lists are lost on which ones work, i'm not sure if an E is.

And while i'm generally a fan of that intake, it's excessive on a 306 with performer heads.

I'd either switch it back to 19's or convert it to mass air.
Good chance i'd run on smaller intake too. Did someone check to see if the intake port on the heads was as large as the lower intake port?
I'd had that intake and a handful of others, everything i've ever run was port matched professionally, so i don't know if they match up.

 

[86HO5.0]

E-Cam is NOT SD friendly.

19's aren't enough for that combo, that being said converting back to them is a good idea for troubleshooting purposes.

 

[2000xp8]

While i would run 24's and the correct meter.
19's have been used successfully on better combinations than that.
My guess is that's like 280rwhp, 19's will goto about 300rwhp and have been used in the past on the TFS kit. Not optimal, but this is a speed density situation.

 

[86HO5.0]

I shudder at the thought of running 19's to 300rwhp.

My basic setup was logging 100% D.C. at WOT on Explorer 19lb injectors. Stock GT40P heads, stock cam with 1.7RR's.

Changed to 30lb injectors and all is golden.

 

[Mustang5L5]

One thing that stood out to me is the lack of any mention of a MAF. Are you still on the stock speed density ECU? If so, you are going to need to convert to an A9L setup...or go aftermarket ECU.

 

[Noobz347]

I shudder at the thought of running 19's to 300rwhp.

My basic setup was logging 100% D.C. at WOT on Explorer 19lb injectors. Stock GT40P heads, stock cam with 1.7RR's.

Changed to 30lb injectors and all is golden.

I've pushed 19s farther than that and this is not a 300 HP combo.

I picked up a used MSD 6AL (part #6420) ignition box. Would this benefit my setup, or is it unnecessary with the Terminator X?

Nope. It will make about zero difference and add another point of failure.
The stock ignition system in these cars is pretty stout when all of the components are in good working order.

My OEM ignition system has no issues with my blown 400+ HP/TQ combo.


The combo is not ideal. Small heads, E-Cam that like low to middle range and an intake that doesn't wake up until 3500+ RPM.

Your flat top pistons are likely stock. Who bothers to swap pistons into an 86 block without valve reliefs?
I'm putting your [peak] HP somewhere in the neighborhood of 260. I do not see 100 HP over stock in that combo.

If it were me:

I'd toss that cam and get something more modern (or don't. Just don't expect 300 HP)
Swap the intake for a Cobra or equivalent truck intake
Do a MAF conversion and maybe even consider the Cobra ECU if you want a no-hassle method to run the 24s.
Install an adjustable FPR to help with the [details] and tuning at the end.



Notes about the o2 sensor harness:

The O2 sensor harness jumper MUST match the ECU type (manual vs automatic calibration).
If mismatched, it can feed 12V into the wrong ECU pin and permanently damage the processor.
Always verify or repin the O2 harness when swapping ECUs.

 

[So_Flo]

Wow, this thread went left pretty fast.

For clarity — I’m still running speed density (no MAF). It’s an ’88 setup. I have the 24 lbs injectors

I chose not to go the A9L route since I already picked up a Holley Terminator X, and from what I understand, the aftermarket ECU should be a better fit for what I’m trying to do. Correct me if I’m off on that, and doesn't this Holly system incorporate the MAF??

I’m currently running an adjustable fuel pressure regulator with a gauge set at 40 psi for now, if that's your question about the METER?

As for the combo, I didn’t originally check manifold port size vs. E303 Cam compatibility. I picked up the cam, heads, and intake years ago when I first started this project, and had zero knowledge, but got everything for under $1000, which was hard to pass up.

I say 275 hp

 

[86HO5.0]

Put the 19's back in. A FPR (fuel pressure regulator) is completely different than a MAF (mass airflow sensor).

The Holley setup might have an MAF option, personally I wouldn't utilize it, keep it SD. Very few people utilize MAF with an aftermarket ECU.

 

[2000xp8]

Wow, this thread went left pretty fast.

For clarity — I’m still running speed density (no MAF). It’s an ’88 setup. I have the 24 lbs injectors

I chose not to go the A9L route since I already picked up a Holley Terminator X, and from what I understand, the aftermarket ECU should be a better fit for what I’m trying to do. Correct me if I’m off on that, and doesn't this Holly system incorporate the MAF??

I’m currently running an adjustable fuel pressure regulator with a gauge set at 40 psi for now, if that's your question about the METER?

As for the combo, I didn’t originally check manifold port size vs. E303 Cam compatibility. I picked up the cam, heads, and intake years ago when I first started this project, and had zero knowledge, but got everything for under $1000, which was hard to pass up.

I say 275 hp

A deal is only a deal if it's the right parts for you.
Using a $1500 standalone negates all of the saving and then some.
Then you may still pull your hair out installing it all and getting it to run right on top of the fact that is still too much intake.

This would have been as simple as a mass air swap, trade the intake for a gt40 (could probably get someone to give you a GT40 tubular for an RPM II), keep your 24's add a pro M meter and drive. It would have ran and idled just fine.
Now it's complicated and expensive, not to mention all this work for mediocre power gains.

Do some research on mass air meter foxes, which began in 89 and i believe 88 in California cars.
This is important information to understand before going any further.

 

[Mustang5L5]

I chose not to go the A9L route since I already picked up a Holley Terminator X, and from what I understand, the aftermarket ECU should be a better fit for what I’m trying to do. Correct me if I’m off on that, and doesn't this Holly system incorporate the MAF??

You actually don't need the MAF with the aftermarket ECU. Very few go MAF with standalones. There are benefits to it, but a lot of folks tune these to Speed Density and get them to run fantastic. You can certainly go MAF if you want with the Holley.

1. Does anyone know of a reputable shop in South Florida that can wire and tune a Holley system? Ideally looking for someone with experience specifically with Foxbodies and Holley EFI.
2. Would it be worth converting to an electric fan setup (before Holly installation)? If so, what fan setups are you guys running or recommend?
3. Should I upgrade my alternator? The car currently has the stock 75 amp unit. The only added electrical load right now is a 12” subwoofer and HID headlights. If I upgrade, what amperage should I be looking at?
4. I picked up a used MSD 6AL (part #6420) ignition box. Would this benefit my setup, or is it unnecessary with the Terminator X?

Holley EFI is pretty popular with Fox cars, so shouldn't find any issue finding someone that can tune it. I don't have anyone I can recommend however.

E-fan is a popular upgrade. You can certainly do it now, or after the holley. Do you have any skills to wire it in now? I run a Contour fan with LMR's bracket kit, with a Infiniti OEM PWM controller. It's tied into my Megasquirt so I can control it via the ECU and really dial in when the fan comes on and how fast it spins. I've helped folks set this up with Holley as well, but the downside is you cannot control it this way with the stock ECU you currently have so you'd have to run a standalone PWM controller. Good mod after you get the holley setup, you just need 1 wire to the controller for the PWM control.

I think any Fox would benefit from a 3G 130A conversion with 4G wire. I've tested my own car and with everything running and the e-fan going, it's only about 90-100 amps total. 130A should be plenty. 200A is overkill considering you need to run much larger wire sizes than 4G if there is any chance of actually pulling 150-175A or more on the system...which I don't see happening outside of a competition stereo build.

My opinion is the 6AL is not necessary but others may feel differently. Might want to research what other folks are doing with their Holley

I'd also recommend adding a provision to put a fuel pressure sensor where the Schrader valve is and wire it into the Holley.

 

[SorsCode]