Hi all,

I've done some part-throttle tuning to get my BLM's right around 128, and am now working on WOT stuff. I've been noticing that as rpm increases, the A/F ratio (as reported using Craig's software) decreases i.e. goes from about 12.1 @ 2000 rpm to about 11.1 @ 4000 rpm. I'm assuming that I can trust this. As an aside, I'm using a 3rd gear 30-75 mph roll-on measurement to assess performance (again with data from Craig's program.)

I made some slight changes in the Power Enrichment vs. RPM table (WinBin) but it didn't do anything (no noticeable change in either A/F or BPW). I'd appreciate any advice.

Also - I've been having trouble getting through to this server. Are you guys having problems too?

thanks

 

Unless your using a WB you probably won't notice any changes. You need to do WOT with a timer of some sort. The PE vs RPM is 1% increments.

 

Thanks Grumpy,

Guess I was expecting to see a change in the BPW, even if the A/F reported values didn't change much.

Using the timer in Craig's program seems to be a fairly consistent way to monitor changes. I use 3rd gear, the same stretch of road, and make sure I've hit WOT before 2000 rpm. Revving to ~4800 or so keeps the speed fairly reasonable and allows the motor to wind a bit. The first leaning attempt moved my 30-75 mph time from ~6.6 seconds (avg.) to ~6.2 seconds. I have to do more runs - not sure if .4 seconds is "real" or normal variation.

Also, this car came with a 305 and now has a 350 - I don't think the knock sensor was changed as I never have any knock-retard (and I can hear a bit of audible knock) - have to check this out.

 

Your Knock Sensor is going "deaf" due to saturation. Thus it basically stops working and you get the FULL timing. You can try using a 350 KS, but don't be surprised if it does the same thing.

Once you get your timing past a certain point with the spark advance (anywhere from 27-32* depending on elevation), the KS can get saturated from noise and then you start to hear audible knock. A common place this first starts occurring when you go "just a little over" is during the upshift.

Make sure you note your real EFFECTIVE timing also. This is your total Spark Advance less your Knock Retard. Generally you will see the Total Spark Adavance pretty well the same, but your Knock Retard dropping to near zero when audible knock occurs. Guys that "cap" their Knock Sensor in WOT tend to notice this more, along with guys who either reduce the "attack rate" or accelerate the "recovery rate" The best solution is to "back off" the timing until the audible knock disappears.

 

Looks like Glenn covered the timing deal.

No probs here with the server.

As for not noticing anything when changing the figures in the PE% change to fuel/air ratio table goes, I really can't say why that is. I haven't actually tackled that part of my bin yet, but I have heard from others that it works very nicely at leaning ot richening WOT stuff.... What figures do you have in there? I still have the 'stock' ARAP figures in mine and my car (without having a WBO2 on it - wince -) seems to be a bit rich at WOT so I am planning on slowly working at decreasing those figures (they are negative so the number will be higher but it is left of 0 on the number line so it is decreasing - bear with me if you already knew that ).

As good as Craig's program is (you da man Craig ), I would not rely on it's air fuel ratio figures as they are not coming from a WBO2 so they are probably not very accurate.

 

Hmmm...

(Server came right up this a.m. - maybe my luck is changing. Usually it waits forever, then times-out.)

Negative numbers? I decided to modify my stock bin (AKFY) as the car seemed to run pretty well. AKFY is for a 305/5-speed, but this car now has a 350 (with stock prom.) The "Power Enrichment vs. RPM" table in WinBin goes from ~13% @ 1600 rpm to about 35% from 4000 rpm and higher. These are after I lowered them. Stock numbers were 14% and 38% at the same engine speeds. I guess the changes I made weren't big, but I was trying to be conservative. The BPW was basically identical at identical rpm and LV8.

I'll pull-up the ARAP bin and check it out. I don't understand the hacs well enough yet to make any other changes. Like Grumpy says, you should use performance, plug chops, etc. for WOT stuff (until I get a WB).