The angle of the barn door.

 

Yes - and that is why I am trying to find the Bosch AFM datasheet for the 0280203029 AFM in the S2. It will give a clear answer to how much flow is possible.

PS - WOT will only give max voltage at high rpm - you can still have WOT at low revs and be well under the AFM measuring limits.

 

Ok, but what causes the angle of the barn door to change?

 

I.e., when the vane/flap/barn door is fully open? Yes? Nothing more to it than that? (Apologies for the mini-hijack -- I thought from what you were saying there might be more going on in an AFM than I thought.)

 

Out of interest, what's the measurement limit of the AFM for the 951 compared to that of the S2?

 

Some info here:

https://rennlist.com/forums/showthre...ferrerid=27835

 

Mike,

Interesting stuff. Let me know how you go with your supercharger kit.

I would have thought you still needed some sort of pressure reduction in the intake when going off throttle - otherwise wouldn't that pressure wave coming back upset the AFM?

 

Suprised no one else brought this up. What about just using MaxTune? I downloaded the trial "example" version and it allows for a lot of control. Probably not as much as a Motec but for the money it looks like the way to go in adjustable tuning.

Right now I'm planning on using MaxTune when I supercharge my NA, but thats going to be a long time from now. Is there some reason no one has mentioned MaxTune?

 

So you also need an Ostrich (or other) emulator to plug in between the ECU and computer, right? What do these cost? How do you get the base map into MaxTune? Do you need to copy your EPROM and then load it into MaxTune - is this possible?

 

Yes you will need Ostrich. Its just a generic chip that fits in the DME and holds memory. You then cut a slot in the DME to feed the cable between your laptop and the Ostrich. MaxTune actually comes with base maps for most 944's. You then hook your laptop up, and load one of the base maps. Then you use a wideband o2 sensor to start tuning.

This is my understanding of how to use MaxTune.

Ostrich2 costs $175
MaxTune costs $150
Mulitboard (MaxHp product that replaces the ostrich when your done tuning, and holds 8 chip images. Not necessary but I'd be getting one) costs $100

Correct me if I'm wrong about any of this.

 

Nope - no different to the NA situation. There is nothing but pipework between the butterfly and the AFM.

 

Yes, good call. I had brain fade when I listed options for tuning the Motronic. If you're using the original AFM then the Motronic is very good at doing what it was designed for, and Maxtronic good for tuning it.

You still need to figure out a system for logging tuning parameters eg WBo2/RPM/duty cycle/AFM/advance etc etc though. This is where Vitesse can help...

 

So a tuning parameter device would just log the AFR vs. RPM, for example, So that you wouldn't be guessing where the MaxTune images need to be edited? And you would have the exact info.

I remember someone posted on here that they were having trouble guessing what the throttle input was during live tuning and asked Russell Berry if he could make MaxTune highlight which part of the maps the DME was currently using. I I'm pretty sure Russell said he could do it but I have no idea if this feature is in MaxTune as of now.

If the purpose of a tuning parameter logging device is what I described above, and Russell did put the feature I described into MaxTune then you shouldn't need a tuning parameter device. Right?

 

Sorry - I was thinking of the throttle body, not AFM. ie BOV between supercharger and throttle body.

 

How ?