Please do let us know your results!!

 

Take a look on wikipedia's entry for catalytic converters. Specifically the first bullet in the "criticisms" section. In summary, 3-stage catalytic converters don't work well unless the AFR is stoich. Basically the cat won't work effectively and long term exposure to lean AFR mixtures might damage the cat (I'm not sure).

 

Looks like the ideal condition is slightly over stoich, 14.8-14.9, but if you run lean you will favour the Oxidation reaction over the reduction reaction. Question still exists if running a 15.4 AFR will that kill the cat.

 

You will not be doing the cat any favors in the long term, but then again...if you care about emissions why change from the standard cruise AFR ?.

 

Well I have been testing this method these past few days and I am getting inconsistent results. Here is what is going on:

When I drive the car at 2750-3000 rpm everything is fine and the most AFR data points are in the 15-15.4 range. It is perfect. The speed is around 60-63 mph.




But when I drive the car at a 3000-3250 rpm even with the same load cell the AFR falls back to stoich The speed is around 65-67 mph.



I think it has something to do with the TPS becuase when I graph the 15-15.4 AFR numbers using TPS instead of load on the x-axis it looks like this:



But when the TPS is higher in the second log, the AFR plot using TPS as the x-axis looks like this:



So how do I fix this to make the 15-15.4 AFR more consistent. I have attached the open loop 1 and 2 table as well as my high octane fuel map.

 

apparently the open loop throttle (tps) maps might need a kick in the butt as well. I am really wondering why I havent had these issues, maybe something else is messed up on my car that is keeping it where it is?

 

Johnbradley,

I thought you mentioned that others were having success as well...I wonder how many people all together are running these changes...

 

There were as I recall...I dont remember everyone having problems. However Bryan (Razorlab) and NJ are having inconsistent results. I suggest that everyone currently doing this and watching this thread (hopefully they still are) chime in.

Me first (though Lucas English has also done this with my results as well):

Results-
15.2-15.5 cruise AFR
26mpg for me with 275 RA1's at 80mph on flat ground on I5
no drop out issues, maintains openloop as verified by logs and watching the WB.


In case Lucas doesnt see this (he is at SEMA right now) I will post for him that he achieved a best of 29mpg (couldnt break 30) on a trip from WA to san fran. Any leaner than 15.6 and he was using more TPS to offset the lean cruise AFR. He is the one that put me on to this also. He was using 850's at the time but was on gas and not E85 (though he has gotten 22 with E85).

 

mine seems to work fine until i get over about 85 ish.... until then, my cruise afr's are about 15.2 to 15.6. I made it from my house to my buddy's house in Va, right about 300 miles or so, and still had a little over a 1/4 tank of gas left. I probably would have gotten maybe 350 or 360 on that tank id bet

 

Also seems to be working fine for me..I had problems before I changed Table 1 to match Table 2. Now I am seeing pretty consistent results.

 

Could you show us all your tables?

 

Ditto ^^^^

I'll be making my changes tomorrow after school, i'll post up some results hopefully then too!

 

i can, sure.... mine was setup my JB directly though so whatever he suggested in this thread is what he did to mine. Which tables do you want to see and i will post them

 

I don't mean to take over, but could you post your open loop # 1 and #2 and high octane fuel table? I'm assuming nj1266 wants the same

 

sure thing... let me set it up and ill post it...