schwett

the two lines are datalogs from about minute apart, both going uphill in fifth gear at full throttle. the blue run is with the BTC all the way at the minimum, the red line with it all the way at the maximum (most retard). there was no audible pinging either way, but then again the octane of the gas in the tank is about 95.

the results are not what i expected at all. could there be other factors at work here? shouldn't the blue line ALWAYS be higher than the red line?

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DirtyLude

I'm not sure why you didn't expect this.

The BTC is only supposed to retard timing at certain points. I though it was mostly mid RPM where detonation is most likely to occur. I tlooks fine to me. The red line is definitely more retarded, where it should be. The bit of swinging around the blue (min) setting does is fairly odd.

What does the BTC use to change the timing? Does it intercept and modify the ignition signal directly, like the BTM and J&S, or does it affect the incoming crank signal. If it effects the ignition signal after the ECU, I don't understand how your OBD2 logger can accurately report the BTC modified timing, since it's modified after the ECU sends it out.

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DirtyLude
Mark Higgins

Toronto Prelude Club
www.hondaprelude.to

iranman

He's right. A common myth (that I admit to have believed) is that the BTC is like any other boost retard device, in that it retards the same amount of degrees per pound of boost across the entire powerband. uh uh...it really does have it's own timing curve burned into it, so it removes some here, adds a little there, etc.

Which makes me wonder: if I'm ever to sell off my electronics and go Hondata, would the Prelude EMS work on the Teggies? I.e, do the commerical BTC and the EMS have the same timing curve built in, or did JR 'tweak' them a little to suit the different applications. I hope not...

Damn, you got a point there. It modifies the ignition signal, the ICM. Hmmm...the only way the scanner would pick it up is if somewhere after the EMS the wires for the ICM connect to the OBDII data port. I assumed there was a direct/separate connection (C8 - "K-line") from the ECU to the data port.



schwett: where's the rest of the powerband??
(You didn't take 5th to redline!?! Geez, some lousy experimental techniques you got there... )

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Sina
My JRSC Site

schwett

well, it seems strange that it's only modifying the timing in such a short area.

it may well be that the logger is not accurately reporting what's going on. my mechanic believes that the btc modifies signals before the ECU, and that the ECU has an opportunity to adjust it further. If this were true it might be necessary to reset the ECU once in a while to keep the ECU from unlearning the changes to the timing curve.

i dunno if i buy that, but it should be easy enough to figure from the wiring diagram. gotta go to work now though...

__________________
"AIDS is not just God's punishment for homosexuals; it is God's punishment for the society that tolerates homosexuals." R.I.P. Jerry Falwell.