turbotalon92

Not an S2000 owner, but in to cars period. I am in the process of installing a e-manage on a friends S2000 and had some tech questions and ideas. First of it is a turbocharged (50trim) car with built internals. He originally put an AEM on the car and could not get the certified AEM installer to tune it right for him. Please don't tell me how he should have stuck with AEM, because I am in agreement, but it is not my car. He decided to go with e-manage and keep the factory computer. Here is where my problem/questions arise. He still has the AEM 3.5 bar map sensor on the car, which throws all the common settings everyone sets their base up on, out the window. I figure the MAP sensor has a range of 1-5volts. Using the numbers I have found on the site, the factory sensor for this car is around a 1.4 bar MAP sensor. That means that there are ~.200v per psi. This is where everyone gets the 2.9v cut off when boost becomes a problem. With the 3.5 bar MAP sensor (40% larger), the same amount of air should generate .090v and is actually telling the computer there is a lot less air going into the engine than what is really going in there. I figure, and let me know if I am wrong, the is about .090v for every psi in the 3.5 sensor. This is creating a lean condition, which I believe is being somewhat compensated by the 720cc injectors. When ever I try and put the correction factor for injectors into the e-manage, the cars dies from being pig rich. So here is the question I pose to the experts. Any other advice is also greatly appreciated.

1. Should the car have the factory MAP put back in and let the e-manage corect for the injectors? Or, should I try and tune it for the 3.5 MAP, much more difficult?

2. What are the basic parameters for the factory MAP? Specs? What is the most boost someone has made on these sensors and been able to tune with piggyback?

Slows2k

550cc injectors are the max size increase over stock that is reccomended. I believe someone on the board was wable to get 600cc's to work. The MAP Volts are reduced reduce the Duty cycle of the injectors. I believe the 720's are too big for the PCM to control with a reduced MAP sensor signal.

How much boost is your friend trying to run? The stock map sensor can read up to 11/10psi, but as you know the MAP volts have to be clamped under 2.9V to keep the stock PCM from seeing boost. The MAP sensor still inputs a higher voltage to the emanage over the 2.9V

The stock PCM isn't calibrated for a 3.5bar Map sensor. Trying to tune off it's different voltage scale would be quite difficult.

double11

your on the right track with calculating the voltage, but often times at the end of the range on a sensor, the scale is not linear... you really need the voltage output graphs from the manufacture to attempt to calibrate or make a scale to work with.

What about using the MAP sensor signal modifier from Comptech...

http://www.comptechusa.com/store/340050.html




I thought the oem honda map sensor was 1bar. You should be able to tune up to 10-12 psi with the factory map sensor...


Slows2k- "The MAP Volts are reduced reduce the Duty cycle of the injectors"

you mean, as the ecu see lower voltage from the map sensor, it shortens the pulse width; right?



I would have stuck with the aem ems as well..

Slows2k

A Comptech ESM is a MAP clamp. It's the same function as the Boost cut built into the E-manage.

The Reduced MAP volts/sensor input is an indirect modifier of the fuel injectors. You fool the stock PCM into removing fuel by reducing the MAP volts. This shifts where on the stock PCM's programing map the PCM operates on. Lower the MAP volts, less fuel. There is a limit to how much you can reduce the MAP sensor volts, that's why Greddy reccomends 150% larger than stock injectors.

turbotalon92

Currently, the car drives pretty well with no adjustments. No one can tell me that 550cc injectors is all you can get in these cars with factory ecu. DSM guys have been fooling the factory ECU for years. It seems a little rich as you get the tale tale smoke when getting on it in 1st and a little sputter if yo step into it too fast. The car will most likely run close to 18psi on pump (7.8:1 compresion). With the larger MAP and Injectors, it drives pretty close to stock. I have only been able to use EGT's for tuning as I have not hooked up his wide band yet. I get no more than 650 degrees C. This is way below the 900 degrees which is about the right temp for 3rd full boost at redline. Like I said though I have only got on it good in 1st to prevent any mishaps. It made about 10si and felt really good. I believe if a can get the conversion right, this may just be a good way to control the injectors (720's) pretty well. Any other thoughts? My math tells me the 3.5 MAP is about 40% larger than stock and the injectors are about 50% larger than stock. The stock injectors are 380cc? This may be where I am getting my math wrong as I am not familiar with the factory injector size.

Slows2k

Factory injectors have flow tested anywhere from 360-380cc's

380cc+150%=570cc

380cc+200%=760cc

The 720's are bigger than the reccomended max.

Your in uncharted territory with the e-manage here.

turbotalon92

I have not done one thing with e-manage yet. You don't always have to follow convention, if you did, every FI S2000 would be supercharged. . If you look at what I am talking about here you will understand that the e-manage does not know what injectors are in the car and the ecu does not know what injectors or MAP is in the car. As the car sits, the e-manage will have to control injectors it "thinks" are only 10% larger than factory. Sit back for a minute and use the facts that are present and you will understand what I am talking about. The only task here is to tune the car for the 3.5 bar MAP.

Now lets make this a good thread and talk about the potential here.

Slows2k

If you can get it to work, more power too ya. I've fooled enough with my emanage and Little 440cc's to know what kind of changes the PCM will react to, and which ones don't make it happy. I'd get prepared to start pulling and clearing DTC's if I were you.

1st gen DSM PCM's are a little more forgiving than this one.

i'm not giving you a hard time, you just have a bunch of work cut out for you. Good luck.

turbotalon92

the e-manage "thinks" the injectors are only 10% larger than stock.

RT

e-manage "thinks" what ever you tell it to