aftermarket ems

[JointTech]

if you are doing a frame off where everything is easy to get to and being redone anyway is there a disadvantage other than price of using an aftermarket EMS like FAST or Atomic or Megasquirt?

The main disadvantage I see if you are just doing a swap is dealing with the wiring harness. But if everything is exposed already that kind of negates that problem. all the systems above seem to still use oem sensors.

My reason for asking is Ill be putting on a turbo which made me go looking for a boost controller, which led me to AEM plug and play EMS which led me to FAST and Atomic and that whole can of worms

[BR3W CITY]

Needing a stand alone transmission controlled kinda puts a damper on things.

The factory ECM can deal with boost when properly tuned.

[Matt Cramer]

Here's my take on the pros and cons of both.

Factory LS EFI:
If you're working with a factory LS1 car, the computer and wiring are already installed; you just need something to tune it.
Since it's built for the LS1, it's tough to accidentally tell it you have a 5 cylinder Volvo or other things that a universal system needs to support that would be horribly wrong here.
If you've got an automatic, you can tune it without a separate box.
Drive by wire control, if needed.
A massive disadvantage: No known tuning programs have cracked the individual cylinder trim tables. They're dialed in for a stock motor, and likely to be way off on a turbo build.

Aftermarket standalone systems:
You have full access to all the ECU's settings. Not locked out of anything.
Many of them have adjustable cylinder trim. Some just use one across the board number for a cylinder, while others have tables. Tables offer more flexibility: You want to pull fuel from a single cylinder at idle, but not at 3000 RPM - you can do this. Same goes with timing.
Boost control. Some of them will even do things like boost by speed or gear. While a factory ECU can be set up to handle boost, I'm not aware of any mods that allow one to actively control it.
Two step rev limiters are easier to set up. Some can also be set to use a timed ramp-up of boost and timing after launch.

[JointTech]

great post thanks.
Im going with a Richmond 6speed most likely so auto trans wasnt an issue in my thoughts.

Im having a hard time with drive by wire. From reading it seems most aftermarket ems don't do it. So do you need a different throttle body that uses a cable? Does that mean you lose your cruise control as well? I thought they were connected somehow.

probably 6 months before I start buying stuff but its a whole new world of stuff to learn.

[Matt Cramer]

There are a few ECUs with drive by wire control - not sure if they do cruise, though. On a cable operated throttle, you could simply hook up an aftermarket cruise control.

[BR3W CITY]

I would think if the ECM can handle the dbw, then building a cruise for it would be more of a wiring project than a programming issue. The GM cruise control for the DBW boils down to a few switches, 2 if you decide to forego accel/resume.

Matt- I know your a MS guy, but I fee like the posted stock ecm disadvantage is a little bit deceiving for some who don't know exactly what that means. The ECM handles boost just fine, adjusting for A/F/S/T. It cannot do this for individual cylinders. This is a perceived disadvantage to a PRO, but not something that 85%+ modders would list as a dealbreaker... Now if I still liked DSM's, I'd probably be on board with ya. Awd+manual+2step+Boost per gear+e85= weeeeeeeeeeeeee!

[Jon01]

There's absolutely no reason to go with an aftermarket controller unless you're looking at making HUGE power.

Cruise with OE controller is cake be it dbw or dbc, dbw is self explanatory, dbc you simply use 4th gen f-body or S10 stuff. Easy.

[Matt Cramer]

Originally Posted by BR3W CITY

I would think if the ECM can handle the dbw, then building a cruise for it would be more of a wiring project than a programming issue. The GM cruise control for the DBW boils down to a few switches, 2 if you decide to forego accel/resume.

The biggest challenge would be making cruise control failsafe - you don't want it to refuse to disengage, target the wrong speed, etc.

Matt- I know your a MS guy, but I fee like the posted stock ecm disadvantage is a little bit deceiving for some who don't know exactly what that means. The ECM handles boost just fine, adjusting for A/F/S/T. It cannot do this for individual cylinders. This is a perceived disadvantage to a PRO, but not something that 85%+ modders would list as a dealbreaker... Now if I still liked DSM's, I'd probably be on board with ya. Awd+manual+2step+Boost per gear+e85= weeeeeeeeeeeeee!

Not denying that the individual trims aren't needed to run boost, but you can get to a point where I'd rather have no individual cylinder trim than trims that are precisely dialed in for the wrong engine. It depends on the combo.

- Stock motor? Stock ECU would be perfect.

- Naturally aspirated, stock manifold, a few bolt ons and a cam? Fuel distribution would be slightly off, but not enough I'd really worry about it.

- Mildly built, naturally aspirated motor with an aftermarket manifold? You may need to run it richer than ideal to avoid leaning out a cylinder, but probably wouldn't hurt the motor this way. Just leave a bit of power on the table.

- Turbo motor with the stock intake manifold? This does affect fuel distribution enough that I'd rather turn the trims off than run the wrong trims, but again, you could usually get away with running rich.

- Turbo motor with an aftermarket intake manifold? Between totally redoing the intake and the potential for detonation, I personally wouldn't want to run this on a stock ECU.

[69trk]

Reason i went with the holley efi. Self learns, tunnable, boost control built in, if you ever wanted to run e85, pump gas or meth can be easily tuned for it..has inputs and outputs for transbrake or whatever you need them for etc.etc.etc. The dominator will run the transmission shiftpoints and everything you can throw at it...But its expensive...

[JointTech]

hmm and they have a DBW cable. I thought the dominators were for converting carb to efi using a throttle body but looks like it will work with LS as well.

Dominator EFI systems are sold “Build to Order”.

that sounds really expensive.
what did you pay all in if you dont mind me asking? says it requires a harness, sensors etc etc as well.

also it says

Boost control is not currently available.

i think thats why I didnt do much research when I came across it the first time. DO you know differently?

this is a heck of a lot of steps for the ecu.
http://www.holley.com/data/products/...ctionChart.pdf

[69trk]

not sure where your looking. but the holley hp and dominator both have boost control. I have in the neighboorhood of $2800 in mine.

*Fully featured boost control capability eliminates the need for a seperate boost control device.
-can be configured to control boost based on time,gear,speed, and manual inputs.
-gear based boost control configurable by several different methods
-boost builder functions offer the ability to assist building boost on the starting line by altering ignition timing, fueling, as well as nitrous oxide activation.
-can be used as an anti-lag function...

bunch of turbo guys using this on yellowbullet...





*Integrated water/meth injection control

*

[69trk]

Those steps you are referring to is if you buy everything seperate. If you buy the kit it will include everything you need minus a few sensors. I mounted the ecu in the center console and the wiring harness is all hidden and was super easy to install. Just cant wait to get some more money to get the hotside and cold side done so i can play with it...Plus it self learns. But may need some tweeking here or there.

[JointTech]

i saw on their site and in the PDF i linked above in step 15 about not supporting boost.

ok $2800 is still in the window. I was looking at a some momo (i cant remember now) it was around 6k for just the ecu...
Thanks for the info.

hopefully you documented everything in your build thread !!! ill go check it out.

the system sounds nice for sure.