WAI revisited.

[cheapybob]

[quote=zpiloto]

What is the compression ratio and what octane fuel do you run? Maybe its at its limit running with the fuel you are giving it, and therefore if it gets any hotter, it pings and retards?

I think you're probably right. between the heated fuel lines and the warm air it reached the fuel/car limits.

I hadn't noticed the heated fuel lines. How hot is the fuel? DiamondLarry had heated fuel and was having problems, I think he said because the fuel was getting TOO hot, and so he removed it. IIRC, someone said to heat it 30f would be good. Did you happen to test before and after the heated fuel, and maybe notice whether it was retarding spark more after? If the motor is higher compression, it will be more prone to ping on low octane fuel. You might try running a tank of 89 just to see if that solves it, then you'd know.

[zpiloto]

Don't know the temp of the fuel but have not had any problems with the spark until the WAI mod. Had the same problem when I tried the IAT mod but did not think of trying higher octane. I filled up with 93 today and will see if that helps. If not I'll just run the IAT around 100-115 and make adjustments for the different seasonal temps.

[cheapybob]

You might want to see if you need to reset the computer, since it may have detuned itself to allow it to run on what gas you'd been feeding it. On some cars you'd need to do that or it would take a bunch of engine temp cycles for it to adjust. GM's newest designs sense when more than 1/2 tank goes in and reset for octane at that point, but I don't know how Mazda's work there.

[cheapybob]

Originally Posted by zpiloto

Don't know the temp of the fuel but have not had any problems with the spark until the WAI mod. Had the same problem when I tried the IAT mod but did not think of trying higher octane. I filled up with 93 today and will see if that helps. If not I'll just run the IAT around 100-115 and make adjustments for the different seasonal temps.

Can I ask if you tested fuel economy before and after the heated fuel mod and what was the result?

[zpiloto]

I got a little over 3% increase but it was only 3 data point A-B-A. I think there is a thread on it call Heated fuel line revisited. So take the results with a grain of salt. It was not that hard to do and it was not a negitive like the IAT mod or the WAI so I left it on. Here's a picture of the setup.