AEM plug and play LS1 ECM

AEM's Plug and Play ECU for the Chevy LS1, a Swappers Delight!

By Mike Kojima

The Chevy LS engine family is not your grandpa's small block Chevy.  Although it shares pushrods, rod bearings and bore spacing with the old school small block it is in fact an all new engine design with modern architecture. The LS has modern compact combustion chamber, high quench heads with 4 instead of 5 bolts so the ports can be designed for better flow, and a deep skirted but lightweight aluminum block with ultra strong 6 bolt main caps, all features that have more in common with late model import engines than the old venerable small block Chevy.  The LS motor also features a direct coil-on-plug ignition system.

Chevy LS1 engine
 The LS1 engine was found in the Camaro, Firebird, Corvette and the Pontiac GTO and donors for sick swaps are easily found on the used engine market. 

Although import enthusiasts have always tended to look down upon the small block Chevy as antiquated redneck technology, there is nothing antiquated or redneck about the LS motors.  The standard LS1 engine is rated at 310 hp and around 340 lb/ft of torque in stock trim.  Not bad for an engine that weighs nearly the same as the KA24DE Nissan 4 cylinder found in the 240SX.  The LS is also exceedingly easy and relatively inexpensive to extract more power from with simple bolt-ons and a huge aftermarket.

The LSI engine is a common one, available in the Camaro, Firebird, Corvette and the Pontiac GTO so donors are easily found on the used engine market.  The growing use of LS engines on the Formula D circuit has proven that lightweight low-stress large displacement LS engines are a more reliable and viable alternative to highly pressurized turbocharged small displacement engines.

LS1 powered FD RX-7
 Our test car was a Mazda FD RX-7.  The Turbo 13B died and the LS1 went in.  The swap is so clean you would swear that the engine came in the car from the factory!

The LS is fast becoming the new hybrid swap replacing K motors in Nissan S chassis and finding homes in the engine bays of 1st and 2nd generation RX-7's.  Turbo rotaries are finicky and fragile and anyone who owns one knows it's not a matter of if you are going to have engine problems, its when and how bad.  With a couple of swap kits on the market, it's relatively easy to replace the high strung rotary with the reliable LS1 with only a nominal weight penalty.

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Tuesday, March 09, 2010 8:03 PM
"The LS motor also features a direct coil-on-plug ignition system."

Isnt it a coil near plug system with a short plug wire?
Mike Kojima
Mike Kojimalink
Tuesday, March 09, 2010 9:28 PM
Street Surgeon
Street Surgeonlink
Wednesday, March 10, 2010 5:46 AM
I <3 Ellis Juan, and
b drecksage
b drecksagelink
Wednesday, March 10, 2010 6:09 AM
The standard engine is rated at 350ish hp....they under rated the camaro and firebird.
b drecksage
b drecksagelink
Wednesday, March 10, 2010 6:19 AM
I would love to have a LS swapped rx7!
Mike Kojima
Mike Kojimalink
Wednesday, March 10, 2010 6:30 AM
By my research it's an underrated 310 or so. Our dyno results seem to show this as well.
Street Surgeon
Street Surgeonlink
Wednesday, March 10, 2010 10:02 AM
Yeah, I've heard that most of the LS1's were more at the wheels than Chevy rated at the crank!
Wednesday, March 10, 2010 12:26 PM
I love me some AEM EMS. For now it's my go-to stand-alone. The tuning software has a lot to do with that love.
Wednesday, March 10, 2010 1:39 PM
Nice product, but for the $1000 or so price tag it doesnt make alot of sense to go the AEM route when HP Tuners and EFI Live have extensive LS1 support and the cost is half that of the AEM.
Mike Kojima
Mike Kojimalink
Wednesday, March 10, 2010 1:54 PM
It can't do half of the stuff the AEM unit can and it can't run in different modes like Alpha-N so it won't have the super throttle response. Also tuning OEM ECU's is somewhat not exact, table edits are more like suggestions than actual values as they are constants in an algorithm. Thus its hard to get a perfect tune.

Tuning mild street builds is ok in an OE ecu but a performance build will run generaly better with a standalone. The driveabilty improvments are very noticeable.
Thursday, March 11, 2010 3:42 AM
I have yet to tackle Alpha-N tuning. Right now it's the boogy man in the closet. I'll open the door when I have to. =[]
Mike Kojima
Mike Kojimalink
Thursday, March 11, 2010 6:56 AM
Alpha-N with MAP correction gives really crisp throttle response and good driveabitly, you don't have the lag that MAF cars have. I was suprised how nice it is.
Thursday, March 11, 2010 2:21 PM
Drop one in that 300zx Mike.
Friday, March 12, 2010 4:21 AM
Oh, don't get me wrong. MAFs are the devil. I just have both feet into MAP+IAT tuning. Never had the absolute need to go to TPS+RPM(+MAP) so I've avoided it.
Street Surgeon
Street Surgeonlink
Friday, March 12, 2010 12:22 PM
HP tuners and EFI Live might not have half the stuff the AEM unit does, but it does offer 1,000,000 times the reliability factor. Not to mention tons of support unlike the AEM (lol user forums for "tech" support...)
Mike Kojima
Mike Kojimalink
Friday, March 12, 2010 12:53 PM
In addition to the user forum, AEM has a tech support hot line manned by two dedicated employees. (800) 423-0046

Do you have quantitative data to support the statement of AEM being 1,000,000 x less reliable than OEM?

Also do you have experience tuning with reflashing an OEM ECU vs a true stand alone? When you change the OEM tables, you are not getting a easily defined set of numbers, just a suggestion as the tables are just constants in a control algorithm.

This is fine for a lightly modded or near stock car but I have been frustrated when tuning high powered cars with OEM ecu's. You get transient detonation, inconsistent power from run to run, etc. You can see the fuel and timing vary even though the load conditions are the same.

Stand alones are solidly consistent in timing and the fuel might vary some with load and bario corrections with little power variation and crisp driveabilty if you know how to tune.

In a higher performance car I'll take a standalone any day. If the unit was plug and play I would take it in a mild car as well. I am not against reflashing, I do it on Nissans and my Mitsubishi myself but you bet when I got big turbo and built bottom end, I am going standalone.

I will most likely use an AEM plug and play unit on my own spare no expense EVO.
Street Surgeon
Street Surgeonlink
Saturday, March 13, 2010 6:03 AM
Mike, I'm going to answer those in order as best I can.

1. Need data showing that AEM's are flaky? I have tons, though a lot of it is from a forum where I can't repost what is shown there. I can however get you an invite if you're interested, just PM me. Also two dedicated employees to assist how many installed AEM's that are out in the field? I'm sure when you call perhaps you get some more help Mr. Kojima but to the avg. schmoe good luck. All of that aside my biggest problem is AEM's R&D department... The customer.

2. I'm not a tuner, but can tell you for a fact that stock ecu'd cars can easily handle the demands of a high hp setup reliably all day, every day. Perhaps not in EVERY car but in quite a few! Subies, Evo's, DSM's, etc. There are tons of 500whp+ cars (more than double the whp of a stock evo/sti) running around with great driveability, all the factory functionality, and safeguards in place.

That being said I know they'll (stock ecus) give up some ground when it comes to inputs/outputs for various sensors, peripheral devices etc. but come on how many users of motoiq are building 100% all-out racecars?

3. You mentioned stand alones are solidly consistent in timing and fuel, while I would agree with that I would also add that it depends on what ECU you're using and what firmware *facepalm* you've got installed.

I'm not against stand alones (actually own an Autronic SM2 v1.93) and know what a nice unit is capable of. Anyways for your spare no expense evo you should use my autronic, it's for sale :)
Mike Kojima
Mike Kojimalink
Saturday, March 13, 2010 9:02 AM
We didn't have to call AEM's technical support because the ECM worked as promised with no fuss. Our LS powered FD is far from being a race car, it is in fact bone stock breathing through a Cat. We got much improved driveabilty and razor sharp throttle response with a nice gain of power that is consistent pull after pull on the dyno.

I don't like the Autronic, the set up parameter stuff is very general, especially when establishing trigger thresholds although I have no idea which version I was helping tune. The CDI seemed kind of weak as well as we had to close the plug gaps down to 0.018 to get rid of misfire on a NA engine running gasoline which should have been a piece of cake for most CDI's. However I don't know what version it was or the condition of the system or the installation other than basic trouble shooting.

Sure I could tune a 500 hp EVO using ECU flash but I would not want to. When logging I can see that the car is not running what the map says it should be often by quite a bit. Also a MAF equipped car is never going to have the driveabilty of a properly tuned standalone, there is the issue of response lag, the plenum, runners, IC etc act like a big air capacitor. Then there is the issue of the ECU flash shareware not being correct as many of the functions are not figured out by the developers, such as idle recovery, closed loop control, MAF scaling and a few like that. Then there is the issue of topping out the MAF frequency count and having to twiddle that, possibly with external boxes although I haven't paid attention to what the ECU flash community is doing lately.

I suspect the math is not correct on some of the other parameters as well although it might have gotten fixed by the ECU flash community by now. An example is on my car, I am getting over 400 whp with ECU flash with decent driveabilty. However my closed loop control stopped working and I can not get it to work again. Even when I relfash to my saved stock rom image.

On top of this, a big bugaboo is that the factory ECU has a limit on the times it can be safely reflashed before it get glitchy. I think on my car I might have passed it. The community debates if this is true but the manufactures papers on the processors used in the ECU state this and I have first hand experience of the ECU getting weird. So has my buddies at WORKS who developed there own version of tuning software for the EVO.

Then there is the issue of false knock count trigged by aftermarket parts changing the noise signature of the engine causing irregular timing. Even the factory doesnt get this right on stock cars, for instance the 2002-2003 era Nissans, the EVO and a few domestic cars I have messed with a little.

For those reasons, I am going stand alone when I get around to installing a big turbo and Cosworth long block into my EVO. I have reached the limit of great results from the factory ECU, by running it into an application for which it was not designed.

It was fun playing with the stock ECU and I got good results with it but it's shortcomings are apparent when you pass a threshold away from stock. The serious issue is the limitations on the number of times you can reflash.

Sometime its a challange to get the stock ECU to work on race cars, like our Spec-V. I would prefer a stand alone with that but JWT my powertrain sponser whats to showcase there ECU reflashing skills so that car is running a reflashed ECU.
Street Surgeon
Street Surgeonlink
Saturday, March 13, 2010 1:22 PM
Wow, the Autronic CDI is one of if not the most powerful on the market today I can't believe it gave you all that fuss?!?

Anyways, this is less about stock ecu's vs. stand-alone's and more about the AEM itself, which hopefully with their "Series 2" hardware and new firmware, they've addressed the old shortcomings :)
Monday, March 15, 2010 8:20 AM
AEM's forum as a secondary customer support tool is laudable. I think it works very well for most things.

Both run-ins with AEM's tech center (two guys an a phone?) went extremely well. The first time was after I used the forum to research my problem and came to the conclusion that I'd ruined my AEM unit by trying to do something very stupid with it. I spoke to the tech and described my problem. I had the unit sent to them and fixed properly.

Then I had another issue with my setup where I spoke to their tech again who diagnosed my problem (even though they'd never encountered this manifestation of it) and I was happily on my way to trouble free operation.

(The possibility of me being treated better than the average customer is absolutely nil.)

I might be holding AEM's product and support higher than I should because of my experience with other stand-alones. I'm well versed in MegaSquirt and VEMS stand-alone systems and as you might have expected moving on from that to something much more expensive and mature/focused opened my eyes to the possibilities. You don't have to go through all that pain. =D

I don't think their units are perfect, and I'm sure there is room for improvement in the hardware, firmware, and tuning software. I'm a contributing member to an open source engine management project (not MS) and I know what the innards are all about. All of the big names make compromises in hardware (okay maybe not Motronic), firmware and tuning software with varying degrees of stability/usability/etc.
I do however include AEM's EMS in the realm of the world players and at that point it's a lot of splitting hairs.

Heffner feels confident in delivering twin turbo Lamborghini Gallardos to his clients with AEM installed. Knowing that he has to make a name for himself and satisfy those types of clients with an OEM-like experience (forget about the power increases) I think that says a lot for AEM.
Monday, March 15, 2010 9:19 AM
Slightly off topic....

I don't mean to jump on the bandwagon like a fanboy for AEM but I once got an out of the blue phone call from AEM asking to drive my Altima SE-R up to LA because another customer with the same car got a check engine light after installing their CAI. They paid for my gas and offered me some free parts so they could help someone else out. In my experience this level of support is rare in the aftermarket performance industry and a major reason why I/we choose to endorse AEM.
Tuesday, March 16, 2010 6:34 AM
When I said "okay maybe not Motronic" I meant to say "okay maybe not Motec".
So many EMS names floating around in this head it's hard to keep them straight sometimes.
There was a demotivational poster I saw a while ago (can't find it) that showed a picture of a Motec EMS and the caption read:
"Motec EMS
For those who demand properly timed sequential injection at 99,999 rpm and nothing less."

For those not aware, sequential injection has little to no benefit at med->high rpm where the air flow is high and the injectors are likely to be open a good majority of the engine's 720° phase making injector timing completely academic.
Mike Kojima
Mike Kojimalink
Tuesday, March 16, 2010 8:41 AM
A Motronic takes the good points of Motec and Autronic?
Tuesday, March 16, 2010 10:52 AM
Motronic is OEM for BMW (and most VAG cars I think, and Mercedes I think) at least for many years.

Speaking of overkill, I know Bosch has a racing ECU that could basically run a space shuttle. =[]
Tuesday, March 23, 2010 10:25 AM
That doesn't say much, considering a Space Shuttle can be run off of a single backup flight system it carries (which is almost identical in hardware to the 4 main flight systems), and that's only equivalent to about a Motorola 68000 (at about 1 MIPS) found in the original Mac with 1MB memory. The ECU from a mid-90s multiport fuel injected vehicle could probably fly the Space Shuttle. :D
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