anyone try Jean's PWM converter board yet?
 

Been thinking of ordering one. Anyone try it yet? Marc?

edit: confusing the P&H board...

As much as I want to tell you how wel it works, and how much I want to try it...
I cant until i get the damn thing. Its bee a while since I've ordered it (two weeks ago on friday) and I have yet to receive it. Apparently, he chooses the slowest shipping available, but I guess I gotta keep in mind its coming from Ontario, Canada.

As soon as I get it, I will definitely tell you how well it works. I want CL idle so bad, im sick of having my car die when my headlights and A/C come on. I want my car to idle at 850-900, rather than 1000-1100

More info? What is this?

It s aboard that multiplies the frequency for PWM signals. MSII has a problem with using closed loop idle on NB miata cars because our idle valve works at a frequency of close to 500Hz. A stock MSII computer can work at a maxium frequency idle of 457.5Hz, but the problem with using a higher multiplier on the stock MSII computer is that the resolution of PWM DC control suffers more. The less of a multiplier you use for the idle control code, the higher the resolution the PWM idle works at. IIRC, at 2-3 multiplier, it works in 0.2% steps. In 8-15 multiplier, the DC works in 6%-10%, which makes CL idle basically useless when set at higher multiplier.

The PWM converter board that Jean sells is basically an external PWM frequency multiplier. It can work in multiples of 2 to 256, but a miata wouldnt use that higher of a number. If this is used, you will keep the resolution that you want for CL idle, but working at the frequency you desire. When you set the settings on the MSII MSQ, it should be set to a low settings, but not THE LOWEST setting IIRC. I think its best set at a multiplier of 2 or 3, then use the PWM multiplier board to get as close to 500Hz.

Frank, I just got the board in the mail today. Im going to keep everyone posted about the board on Abe's original adapterboard thread, or hell I'll just make a new thread regarding it.

thx Marc, I think it's a good idea to make it a seperate thread. That way, it's easier to find it back.

Can anyone confirm what frequency the NA 1.8 runs at? I have a 96 and I'm trying figure out if I would benefit from the converter board.

I'm having trouble getting my IAC to respond well in CL Idle

400hz IIRC, easy enough to check though just load one of DIYAT's base maps ;)

Yes, but the resolution of the MSII is only in 30.5 increments right? The base map has a value of 13 (so 13 x 30.5 = 396.5hz). Close enough I'm sure, I just wanted to know the exact value. Either way, based on what I'm reading, the error that is present at this value indicates that I would benefit from the converter board. It seems that all 1.8 miatas would benefit from the converter board. Thanks.

Has anyone tried simply running the NB idle air solenoid at 50~100 Hz without using the multiplier board? Would that be enough resolution?

It runs horribly at 122Hz and buzzes like hell. It's better at 305Hz but really, it is intended to run at ~500Hz.

Dimitris

Yup, tried it as well. It was horrible on my car. No way I would drive it without the board. It's completely silent now :).

So did you go 2x30.5 in code and PWMx8 = 560Hz?

Go for 1x30.5 in TunerStudio and 16x on the PWM board = 488Hz.

Running my idle valve at 390Hz. Like butter.