I'm at the crossroads people. I've read about both units controlling 440cc DSM injectors but I'm at a lost as to which one I should use!!!

I am currently running:
D16Z6
JRSC @ 6psi
JR High Flow Fuel Pump (I think it's a 255)
JR FMU
Stock injectors

I've heard successful stories on both set ups, but I really need some good comparisons on how these 2 units fair up against each other. Please help me decide people!

Which one is better? And why?


[Modified by Westsideboy, 3:37 AM 3/5/2003]

 

they're both basically the same. but the vafc can trim fuel by 500rpm the smc+ does it at 1000rpm. vafc is more bling looking, can set vtec, and cost alot more then the smc. wait for the smc500 to come out. the new feature is it can adjust by 500rpm.

 

It's about the same either way, you're running a MAP limiting circuit. The problem you run into with that is this. While it's all well and good to use one of these for fueling. But it's not so good on the timing aspect without some tinkering. The MSD BTM would be a nice addition....



The above is property of J. Davis


[Modified by Speed PHreak, 11:11 PM 3/4/2003]

 

Call me a rookie or whatever you want, but please explain that chart to me.

Instead of the MSD BTM, what do you think about the JR BTC?


[Modified by Westsideboy, 4:11 AM 3/5/2003]

 

Sorry, you have to have a bit of understanding about how the ECU uses the MAP singal. The amount of air being sucked into the engine, causes a vacumme in the intake track, while the throttle is closed the engine exerts a higher amount of vacumme "pull" than when the throttle is open. . When you press the throttle the MAP sensor detects the change in vacumme and outputs a voltage signal based on how much vacumme(or boost) it see's. So the lower range of the chart near 22-20 is your cruising or idling range, where not much load or throttle is being given to the engine. With the pedal to the floor and the throttle way open causes littlle to no vacumme. The wide open throttle(WOT) area is at the 0~1.3psi range usually. So the less amount of vacumme the MAP see's the higher voltage it outputs.

Less vacumme = more air flow = more fuel sprayed by the injectors.

The chart is your basic timing curve map. Across the top are the voltage outputs from the MAP sensor, converted to a tangible measurement(HG/mm or whatever). Down the side is shows some RPM incerments. Now the AFC hack or SMC changes how much voltage the ECU see's, that way it can trim how much fuel the injectors spray. Now the MAP change is not differintiated b/t spark and fuel curves. Basically what that chart shows is how the AFC changes what the ECU sees. Running too much spark adavance can be very unhealthy to your engine under boost.


[Modified by Speed PHreak, 11:58 PM 3/4/2003]