Gernby

I am amazed at how many S2K owners have bought an EMS, then turned around and sold it. I know that they are hard to get tuned, but there have even been owners who have gotten them working WELL, then sold them. What's the deal E yo?

DJSang

I don't think even the major knowledgeable tuners understand the complete tunability and complexity of this thing. That's probably why you aren't hearing from the few people who were either naive or way too excited to purchase the thing...

Steve@Evolution

See, the problem with ems or any hardcore standalone is that they will NOT drive the car like stock. I have one in my car and I must say with 720cc injectors and 80% of my car is aftermarket it's driven as good as it can. The damn thing was designed for racers who needs alot more ajustability than the stock ecu. The trade off?? Comfort. I can blast through 19psi from the motor with pump gas with no worries but I fear idle, temp. change, ecu acting up, infinitive options I havn't touched, fuel economy, and ect ect. Idle is the first I have lost as a tradeoff when I turn on my key the first time and still till now. I can idle like a champ but at nearly 980rpm due to too large of injectors and very close gapping.
I do not own a S2000 but I have several s2k in the shop that is forced induced but fear opening up to ems for help since drivability is a great concern. If you are not racing the car, you don't need it. If you are not running crazy force induction or nitrous, you don't need it. If you are not running crazy high compression with over the roof rpm limit, you don't need it. However, VAFC can only adjust up to 9000 rpm. That's the roof so if you are surpassing the 9k limit, ems offer their tunning surpassing the limit. Exact rpm I am not sure but I think it was above 15k.
Will it gain HP for your car, sure. All you have to do is remap the ignition so advanced and rework the fuel alittle, you gain lots of power. Will your motor last long with that kind of advancing?? of coarse not.

Steve@Evolution

BTW, alot of tuner have already understand the system. It's just take time to get it run right for everyday driving. If I was to tune it, I need the car at least a week and drive it nights and days with the laptop hooked up to get it right. I can however tune the full throttle range in about two hours. All I need is in car wideband O2 sensor.

DJSang

cool, thanks for the info...

cbender

Hybrid,

What are the options, then, for improving tuning without an AEM EMS? I've got an A'PEXi V-AFC, and (if you check out the thread below) I'm really unhappy with mid-throttle tuning in VTEC. Any suggestions? (I knew that I'd wind up coming to see you guys some day.)

https://www.s2ki.com/forums/showthread.php?...&threadid=89887

Steve@Evolution

I understand exactly how you feel about your current fueling management. I used to have V-AFC in conjunction with 440cc injectors. I get the sputtering tip in problem all the time. All most like a fueling lag. Combine with turbo lag, it's not fun at all.
What happen is like you said, during throttle tip in, V-AFC is dumping way too much fuel during the transition from narrow band to wideband. Also, sometimes, there is hesistations during quick stomp of gas since the ecu is trying to lean out the fuel by narrow band 02 sensor and turbo is trying to boost which add more air so you get a lean and then V-AFC is trying to dump fuel controlled by the fuel setting and you get a rich. So you get a lean and a rich process. I have to say V-AFC is not adequate for turbo system because stock honda ecu can't sense boost. I would recommend Hondata but they don't offer a system for S2k. The reason I said Hondata is because they are the only mild standalone that uses your stock ecu for keeping the stock drivibility but adding boost options making it sensing boost. Remember, stock honda ecu uses more of throttle position to determine fueling than like say most forced induced vehicle uses Map absolute sensor or MAf sensor.
Anyother option is to use the V-AFC hack. I know I know, what is it. V-AFC uses Throttle position to determine if the motor is in narrow band or wide band position. That's why you have a menu that allows you to adjust the throttle fueling. Now use that TPS wire and hook it up to MAP sensor in some kind of way and now you have a perfectly mini standalone that can compensate boost.
Example: TPS is count in percentage. 0-100 percent. Most set wide open in around 50% so that makes 0-49% is narrow band and 50-100 % is wideband. closed loop and open loop is then controlled.
If you hook up the MAP sensor instead of TPS sensor, VAFC is no longer controlled by the TPS. Map absolute pressure now tells VAFC how to add fuel. The more boost map sensor read, the more fuel it add. Then you tune the narrow band and the wide and both map must be the same exact values. That is a simple way of defining V-AFC hack. V-AFC hack is only good to 11 psi of pressure as Stock honda map sensor's limit, it's a 2bar map sensor ( first bar is -14 .7 to 0 psi and second bar hits from 0- 14.7 psi but some reason it only read to 11 psi for safety).

Gernby

So is the answer "No"?

Wesmaster

Hybrid, very good info...thanks for the informative post.

I'm currently running Greddy e-Manage, a piggy-back fuel system, on my S2000. I got it up and running prior to the up and coming boost upgrade, and it's been running nicely. It's much more complex than the V-AFC but not as complex as AEM EMS (I have had both on the S2000). The e-Manage can do MAP voltage "tricking", injector duty cycle modification, and injector pulse modification...as well as ignition timing. The MAP voltage tricker works like V-AFC, using TP as one of the axis. The injector cycle and injector pulse use the MAP reading though. I'll be using this when I tune after the boost upgrade. You should look into the e-Manage.

Steve@Evolution

Well said Wesmaster. I almost forgot the E-manage, it's a good option. got a question thou. E-manage control fuel by tricking map sensor to adjust injector duty cycle but really you want the unit to control fuel via map sensor also so it can read boost. If the verticle axis is TP then it's the same as the VAFC then. The reason surpa runs so well with boost because MAF can read how much air is coming in. EMS uses Map signal to determine axis and totally disregard TPS signal. Only time it use TPS is for Idling, Decel, Accel, and other minor situations. Fueling is completely determined by map voltage and RPM. I am not sure so you might want to ask greddy to see it can read boost ( via map sensor for Y axis and RPM for X axis). If the E-manage does then you are set to go.
There is another unit called SMC which is a size like a Greddy turbo timer and all it does is use Map signal instead of TPS to be one of the axis and also uses map signal to trick injector duty cycle to increase fueling.
I know Vafc hack works but it's sometime unstable so in my honest opinion, I wouldn't use it.

Gernby: You never stated what setup you got so I can't give you my opinion.

I was intended to answer the question from Cbender since he has problem controlling fueling from his turbo.