LSx Engine Management

StretchASU

StretchASU

Well-Known Member
Joined
Oct 17, 2006
Location
Creedmoor, NC/Claudville, VA
It seems like just about every company makes a LS swap harness these days and there is a ton of aftermarket. Seems to range from about $650-1200 for the initial harness and tune.

This is more to pick the brains of those more versed in it and what worked for them.

Option 1: get the stock harness cut and ECU flashed. Pro, probably most cost effective. Con, seems to be hit and miss as to whether the startup tunes are worth it and most need retuning in the long run.

Option 2: buy a new standalone harness and ecu. Pro - new everything. Ability to sell stock harness and ecu to recoup a little $$. Con - almost as expensive when optioned out as option 3 and what could be the same startup tune issues as option 1.

Option 3: full standalone like Holley Terminator X Max or FiTech. Pro - new everything, self learning ecu, pretty good tech support and multiple tuners and dealers nearby. Con - besides the cost, I can’t really find any.

Help an over-analyzer decide which direction to go :lol:
 
I've seen some of the stand alone ECU's come with their own dedicated computer programs. Get the engine running, hook it up to a laptop, make a phone call, push some buttons, and the tune is done. All from idling and pushing the gas to the rev limiter a few times, and then it uses the self learning process from there.

I guess if you buy something like that, it's easy to redo the tune when you change things up later like exhaust, or engine parts.
 
If you run the factory stuff on a stock motor, you don't need a tune...unless you mean having to disable a handful of things. For whatever reason, I've always imagined if I did an LS swap, I'd run a factory style setup. I think it's mostly because I bought HP Tuners a while back.
 
For me, it came down to the fact that I was running the LS motor basically stock with the trans it came with from the factory. That meant basically simplifying the factory harness and disabling the PATS, downstream O2s, etc was the way to go.

In the little research I did on other options it seemed most aftermarket systems needed additional items for trans control, etc. If you were going crazy with mods, boost, different trans, especially a manual, I'd go aftermarket.

The harness thinning cost me $300 and $100 for unlocking the computer and "startup tune". I drove it with that tune for about 1,000 miles then went back for a ride along.
 
I think there is a reasonable debate as to what is best.
Instead of simply offering my opinion and confirmation bias like most will do I will only add some additional factors to consider.

Regarding negatives. Where you say none Ive found.

Most of the aftermarket controllers Ive handled are not nearly as robust or hardened electrically as the OEM stuff.
The OEM ECMs have to be able to last 100k miles or it costs them money. They spend more on R&D and Testing and life cycling that a compnay like FiTech or Holley is worth.

Then there is the repair availability fatcor. If a stock ECM shits the bed and you have an HP Tuners account a trip to a junkyard or ebay and a download and you are back in business. In a remote wheeling trip pretty likely you could find an ECM locally. Not as much with the aftermarket.

Final consideration is product life cycle and twilight. This will show my personal bias here. When I first started on the mustang I bought a FiTech Fuel Injection system, by the time I got around to actually installing it FiTech had 3 new version renovations out and the product I had new in box was no longer supported.

I really want to crack open one of the XMAX modulee open and see its internal architecture.
 
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Ron said:
I think there is a reasonable debate as to what is best.
Instead of simply offering my opinion and confirmation bias like most will do I will only add some additional factors to consider.

Regarding negatives. Where you say none Ive found.

Most of the aftermarket controllers Ive handled are not nearly as robust or hardened electrically as the OEM stuff.
The OEM ECMs have to be able to last 100k miles or it costs them money. They spend more on R&D and Testing and life cycling that a compnay like FiTech or Holley is worth.

Then there is the repair availability fatcor. If a stock ECM shits the bed and you have an HP Tuners account a trip to a junkyard or ebay and a download and you are back in business. In a remote wheeling trip pretty likely you could find an ECM locally. Not as much with the aftermarket.

Final consideration is product life cycle and twilight. This will show my personal bias here. When I first started on the mustang I bought a FiTech Fuel Injection system, by the time I got around to actually installing it FiTech had 3 new version renovations out and the product I had new in box was no longer supported.

I really want to crack open one of the XMAX modulee open and see its internal architecture.
Click to expand...

Definitely an interesting way of looking at it. I hadn’t really thought about the life cycle side of things but there’s some merit to that logic for sure.
 
@Ron that really is a brilliant way to look at it. You could get an ECM almost anywhere, and I pretty much always have my laptop with me on a trip for work.


Here’s my opinion based on my YouTube knowledge. I watch the Cleetus McFarland channel a lot, and I’m constantly blown away by the tunability of the Holley systems. Specially when you see it in the hand of someone like Kevin at KSR performance. So many options and inputs available, but that’s in a drag racing application, far different than most of ours for a trail rig. So while I am a huge fan of Holley and their Sniper/Terminator and stuff, Ron makes a fantastic point. The stock ECU properly tuned, and perhaps a file saved and the ability to load that into a new ECM while in Harlan or wherever, would add substantial reliability to the rig. I can’t imagine going 10+ hours away and the aftermarket ECU take a dump and you can’t get one.

A good professional tuner should be able to tune for your upgrades and rig and then be able to email you that tune at a later date if needed as Ron said. That’s extremely valuable.

However if one was starting from scratch with no factory harness, ECU or gauges, a Holley system still wouldn’t be a bad choice.
 
Also depends on what transmission you're going to run. I personally think the factory computer with hptuners does everything anyone would need short of traction and boost control. Like ron said it's definitely the most reliable of those options and if you're running an electronic gm trans too it's almost a no brainer
 
Heck I'll save a lot of trouble I've got ya a factory harness already to go with a flashed ecm with hp tunes and dbw throttle pedal with a semi built 4th gen 6.0 with ls2 intake, fuel rail
throttle body Texas speed stage 2 cam for 2000$
 
baggednissan said:
Heck I'll save a lot of trouble I've got ya a factory harness already to go with a flashed ecm with hp tunes and dbw throttle pedal with a semi built 4th gen 6.0 with ls2 intake, fuel rail
throttle body Texas speed stage 2 cam for 2000$
Click to expand...

Hold onto that thing for a year when I’m ready to rip the crappy blown up V6 out of my wife’s 01 Camaro.
 
IMG_2491.PNG
I'll just leave this right here!
 
baggednissan said:
Heck I'll save a lot of trouble I've got ya a factory harness already to go with a flashed ecm with hp tunes and dbw throttle pedal with a semi built 4th gen 6.0 with ls2 intake, fuel rail
throttle body Texas speed stage 2 cam for 2000$
Click to expand...

You keep that Texas Speed cam and that'd be a deal! :D

FWIW, I have HP Tuners as I said earlier on and a nice wideband, so what I do is data log a cold start, idle, cruising, running up through the gears, a gooood WOT pull, a hot start, and some idling. Then, I email it to a dude in Vegas who charges me 100 bucks with free revisions and he's usually got me an updated tune in an hour or two. It's really nice to have the ability to do that and I'm really particular about my speedometers being dead nuts, so I can still get in there and fine tune that, electric fan on/off temps, and whatever else I may need to mess with. I even have EFI Live for my Duramax too, but don't have the hardware necessary with that to actually tune the truck.

Technology is awesome.

I've always like the function of the factory ECM. They can do a lot of stuff. Boost is no issue and you can change operating systems if necessary. If you're not running an ECM controlled auto, it's usually easiest to start with an OS for a 5 speed truck. Just a lot less transmission codes to disable initially.

I feel like I should finally learn how to tune. Yall crowd could keep me employed, it sounds like.
 
MetalCraftSolved said:
I've seen some of the stand alone ECU's come with their own dedicated computer programs. Get the engine running, hook it up to a laptop, make a phone call, push some buttons, and the tune is done. All from idling and pushing the gas to the rev limiter a few times, and then it uses the self learning process from there.

I guess if you buy something like that, it's easy to redo the tune when you change things up later like exhaust, or engine parts.
Click to expand...

You have seen too many Holley adds and this is just plain wrong.
 
My 2 cents (for an LS system only):

- If you want your install to be 1 and done, I'd get a factory ECU with either a cut down or brand new harness. The nicer the harness the better (for reliability).
- Factory ECUs are 100000x more reliable and weatherproof vs the TermiX
- If you want your vehicle to have advanced functions (data logging, PWM fans and fuel pump, transbrake, ...) nothing will replace an aftermarket ECU that's designed for it
- If you want a fancy luster/digital display, they usually have more functionalities when paired with aftermarket ECUs
- The TerminatorX has safeties built in. You can set up the system to shut down your engine in case of low oil pressure, fuel pressure, lean spikes, and other events that could hurt your engine. For me that's a BIG PLUS for the TerminatorX.
- If you want to tune your car or make tuning corrections yourself, the Holley system is a million times better and user friendly vs HP Tuners / factory ECU route
- If you have a modified engine, or plan to modify your engine, the Holley system is easier to work with (IMO).
- If you have a stock engine and do not care about squeezing the last 5hp out of your setup, the stock tune will work great for virtually no money.
- In case you have an engine that's built (even a cam), a tune by a pro is needed (don't trust Holley's marketing BS, they do not "self tune"). Also valid for a factory ECU system that runs a modified engine but I feel that it's common knowledge.

At the end of the day, I went with the TerminatorX because I enjoy tinkering with that kind of stuff.
To my friends who want to install a LS engine in their rig, not touch it and never worry about it, I almost always recommend a factory ECU with a nice harness and a good tune done by a reputable guy.
 
FWIW, you can do some cool stuff with the factory ECMs. There's a handful of empty pins that you can use to control other functions. I've got factory 05+ electric fans on my 99 and they're wired/controlled through the ECM with customizable on/off temperatures.

There's also plenty of safety features in the stock ones too. Spark, fuel, oil, coolant temps, etc.

Also, unless it's going to see a ridiculous amount of boost, I'd keep it as a MAF setup and not speed density. Using a MAF makes it much more drivable and precise for most normal activities and I've seen a lot of people run SD, for whatever reason, forget they need to add an IAT sensor, and have all sorts of issues. The factory IAT is inside the MAFS.
 
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