Attention Newbies: Learn from my mistakes!
05-01-2003, 05:48 PM
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Attention Newbies: Learn from my mistakes! Ok guys, I have some tips now since I just came back from the dyno. I made 11 runs, best pass of 337HP/348TQ with the cutout open, 324HP/341TQ with it closed. Here is what I learned:
1. Tuning PE is useless at high RPMs if you don't disable COT (Catalytic Converter Overtemp protection). I kept bring the PE v RPM table (near 1.0!) and couldn't muster anything above 11.8:1 A/F at high rpms. After I disabled the COT, my A/F jumped to low 14s!! I brought the PE v RPM down around 1.1 and the A/F went to approx 13.0:1. I would have riched it a bit more, but I ran out of time on the dyno (went .5 hour over my 1 hour schedule, but the guy behind me was cool)
Ok, so now that the COT has been disabled, and the PE v RPM can actually be adjusted, the next thing is:
2. Be careful entering data. I accidentally put the value 1.44 in my PE v RPM cell for 4400 rpm, and the dyno runs showed the A/F tanking off the charts (probably headed towards 8:1!), and the subsequent loss of 40 HP, followed by a nice run. I was thinking WTF, I must be getting some KR. I pulled a bunch of timing at the spot where it was occuring (4400 RPMs)...nothing. I make a few passes with the changes, nothing. I go back to the stock timing table, nothing. At this point I am freaking out - thinking I broke something.
Finally, after finding the error in my PE v RPM cell 4400, the dip was gone and life was good (thanks Perry!).
After 1.5 hours (1.25 of which was spent learning from steps 1 and 2), I gained 8 HP and 5 TQ. Nothing spectacular, but I didn't get my A/F dialed in perfectly (still 13.1:1), nor did I actually get to advance the timing any...BUT, I learned some valuable lessons, and got myself on track enough to actually do the final bits on the street...richen it just a pinch, throw a few degrees of time at it a look for KR.
Again, my mods are lid and cutout. I bumped my rev limiter to 6300, and the car is making 315 HP still...not far off from peak, so anyone who says the stock cam falls on its face must be talking about higher rpms.
1. Tuning PE is useless at high RPMs if you don't disable COT (Catalytic Converter Overtemp protection). I kept bring the PE v RPM table (near 1.0!) and couldn't muster anything above 11.8:1 A/F at high rpms. After I disabled the COT, my A/F jumped to low 14s!! I brought the PE v RPM down around 1.1 and the A/F went to approx 13.0:1. I would have riched it a bit more, but I ran out of time on the dyno (went .5 hour over my 1 hour schedule, but the guy behind me was cool)
Ok, so now that the COT has been disabled, and the PE v RPM can actually be adjusted, the next thing is:
2. Be careful entering data. I accidentally put the value 1.44 in my PE v RPM cell for 4400 rpm, and the dyno runs showed the A/F tanking off the charts (probably headed towards 8:1!), and the subsequent loss of 40 HP, followed by a nice run. I was thinking WTF, I must be getting some KR. I pulled a bunch of timing at the spot where it was occuring (4400 RPMs)...nothing. I make a few passes with the changes, nothing. I go back to the stock timing table, nothing. At this point I am freaking out - thinking I broke something.
Finally, after finding the error in my PE v RPM cell 4400, the dip was gone and life was good (thanks Perry!).
After 1.5 hours (1.25 of which was spent learning from steps 1 and 2), I gained 8 HP and 5 TQ. Nothing spectacular, but I didn't get my A/F dialed in perfectly (still 13.1:1), nor did I actually get to advance the timing any...BUT, I learned some valuable lessons, and got myself on track enough to actually do the final bits on the street...richen it just a pinch, throw a few degrees of time at it a look for KR.
Again, my mods are lid and cutout. I bumped my rev limiter to 6300, and the car is making 315 HP still...not far off from peak, so anyone who says the stock cam falls on its face must be talking about higher rpms.
