EvoCorp

As I was looking at the different piggyback air/fuel management units available, the APEXi Super AFC seems to be my number one choice. However, as I do more research, there are some experts who think/believe that having piggyback units in general may be a bad idea. Because of the sophistication of the Evo's ECU (unlike your 60's muscle car), having a piggyback air/fuel unit may 'cause more harm and/or aggravation in the long run then good. Those experts instead suggest ECU reflashing as opposed to piggyback units. Here are some of their reasons:

1. Piggyback units intercepts signals that the Evo's ECU relies on and changes them before sending them to the ECU. By lying to the ECU, your car doesn't really know what is going on . This in turn can cause the ECU to make possibly dangerous and erratic adjustments based on false premise and can cause more harm than good. This is ESPECIALLY true to the Evo's self-learning and adaptive memory, like the Evo's.

2. Piggyback units, or "intercept boxes", can compromise the communication speed between the ECU and its related components which presents a serious risk to a very dynamic, rapidly changing high-output motor like the Evo's where milliseconds count .

3. Because the Evo's ECU has a memory feature, it saves the mapping and re-mapping each time something is changed under the hood and so forth. Piggyback units prevents the Evo's ECU from getting the "whole picture" and stores false maps to what is really happening or what is really done to the car .

This is a very convincing argument. Although I have seen and heard very good results from having piggyback units on the Evo, having an ECU reflashed instead and have the stock ECU do the air/fuel management instead may be a better idea. I mean, Mitsubishi spends countless hours making and programming the Evo's ECU, so it isn't exactly a shabby unit. What do you think?

mayhem

iTrader: (9)

I would go with the reflash just for warranty and ease of use purposes. Just hook it up. No tapping power sources, no splicing wires. No extra equipment.

twdorris

Those are some pretty broad and wild claims about piggyback systems. Piggyback systems have drawbacks, but the EVO ECU isn't all *that* fancy. Especially related to open loop, WOT conditions where you're looking to do most of your tuning.

If you're going to stick with the stock injectors or if you're just looking to tune out that fat open loop fuel table, a piggyback setup is Jim Dandy. It's a little difficult to get ignition timing right with an AFC because it only alters the airflow signal going into the ECU, but it'll be pretty darn close.

If you're looking to throw big ol' 950s injectors into the mix and try to dial it out with an AFC, you'd better really know what you're doing and, most likely, you'd better have some way to get your ignition timing right.

For now, if it were me, I'd go with an ECU reflash. All they're doing right now is chaning fuel, timing, and boost maps, but that's a hell of a lot easier to deal with than an AFC. If all you're looking to do is to get a little more fun out of your relatively stock setup (no huge turbos or big engine mods), then the standard reflash will probably do you well.

I know nothing about them personally, but the Works guys "seem" to be taking a reasonable approach. I'm not directly recommending them as I don't know enough about their operation, but they're at least talking a good talk. I can and will likely be doing my own ECU reprogramming soon, but even so, I might check out the Works ECU anyway (even though they're ignoring my e-mails to them). They're putting in a good bit of work up front and it's so painfully simply to just drop it in and drive the car. I like simple. Especially with a brand spanking new $30k car. Once I get over the cool newness of the car (maybe right about the 36,000 mile point) and decide to start really tweaking and racing the thing, I'll start doing a bit more radical changes to it. For now, a simple reflash will do nicely.

Thomas Dorris

mayhem

iTrader: (9)

twdorris, good points! I talked to David from Works yesterday on the phone. They've been at the track all weekend, so they weren't getting my emails either.

But anyway, what you want shouls reflect with what you are GOING to do in the future. I might go with the piggy back if I knew I would be doing heavy tuning in the future. If you're doing constant tinkering then the reflash probably isn't for you. If you just want a good install and forget upgrade then the reflash most likely is for you. I'm just one of those 'lets squeeze a lil more power out of her and call it day' guys. So I won't be doing much tuning.

N10S

iTrader: (4)

Without a doubt there are several reasons that the piggy-back fuel tuning, and standalone boost control mod path are popular with EVO owners.

1) There are DSM tuners with years of experience that have been able to successfully apply the same tuning logic to the EVO with excellent dyno-backed results.

2) This path offers a lot of flexibility when tuning objectives are targeted for major power gains, especially when jumping to bigger injectors, turbo's, etc.... .

3) There simply haven't been many good alternatives!

Having said all of that, I think the Works ECU re-flash and XEDE unit being offered by Vishnu are the beginning of excellent alternatives available for the EVO 8.

A lot of people underestimate the hp/tq that can be unlocked through careful ECU tuning.Many people think this is a low hp option, not for the hard-core gear-heads we all aspire to be. The truth is that a lot depends on the level of granularity the tuner uses when adjusting the timing , fuel and boost maps and his ability to make these adjustments through countless dyno sessions.

The tuners scope for packaging tuning options will also define the limits to some degree. For instance an option might be one program for a stock exhaust, another with axle back/cat-back, another with full turbo-back. If desired a special program could be developed specifically for a car with all of the above and say...a set of HKS cams? It just depends on how far the tuner wants to(and can)go within the capabilities of the stock ECU.

Even at a very basic level major power can be unleashed through ECU tuning of turbo cars. For example I ran an MTM ECU in my first S4, and an ABT ECU in my second. Installation took all of 15-20 minutes and the results were an additional 55-60 hp over stock.We are talking major day/night differences in performance folks.

Many people talk about building the 400+ hp EVO beast,and more power to them.In reality though, most folks would be really happy with a plug and play solution that jumps you 40-50 hp, or possibly even more when combined with a other complimentary tuning parts. It is especially attractive when you know it is a wholistic tuning solution that dynamically adjusts timing, fueling, and boost with absolutely no add-on parts or pieces.

I personally believe that once the re-flashed ECU's and XEDE units begin to make it into more peoples cars we will be able to make better tuning choices based on our needs, and not on "whats available".

My .02

Orion

hows about an AEM system? i have heard that theyll have an evo8 application roundabouts the mid-summer time. i have heard really good things about those from my freinds in the supra community.

SRD

The AEM unit is a standalone right?
But user friendly...

SRD

looks like it is, and all for probably around $1600.

quickass_vr4

iTrader: (1)

The AEM system is great I run one in both my vr4 and stealth TT, When they become available I will probably be getting one for my EVO, though I think until then I will go with piggybacks.

The AEM is a plug and play system, though it is not for a novice to tune for sure....though with it you have pretty good control of almost every aspect of the car/computer relationship.
You can even remove the MAF freeing up even more power, but not withoug getting other things like a wide band 02 as well as a 3 bar map sensor.

MalibuJack

iTrader: (5)

I'm doing exactly that.. I will be running an S-AFC for now.. once I find a good (Local) tuner with an AWD dyno, I plan on getting the AEM EMS system.. I am going to install (currently) the wideband 02, with the AEM Dual channel output so I can set it up to work with the stock computer, and have the wideband controller to tune with. Just so you all know, the AEM pricing for the EMS is about $2000, it is plug and play though with base maps (that duplicate stock) and a learning mode.. However they recommend it being tuned (Initially) by a pro, which is what I intend to do.

bone324

You can't go wrong with Vishnu's XEDE. I haven't dealt with Works, but I know from personal experience that Vishnu will only produce the BEST, and most dependable products for power. If an AFC were better, Vishnu would produce one.

Hedonic Tread

Excellent thread. Just to clarify, exactly what is available right now in terms of ECU reflashes and piggyback units? From what I have been able to figure out from these forums and visiting various vender webpage, the are no ECU reflashes available just yet (although Works will have theirs out soon), and only one piggyback (Vishnu/Shiv's XEDE). What are the other options?

3K

iTrader: (9)

You could probably get the HKS F-con V to work on the Evo. Also Apexi has their Power FC for the Evo Vll in JDM, that "might" work.