Bad day at the dyno with a 5177
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From: Highlands Ranch, CO
Bad day at the dyno with a 5177 Finally got the 5177 kit installed with a 125 shot. Went to the dyno shop but got horrible results:
425rwhp, 367rwtq <img border="0" title="" alt="[Frown]" src="gr_sad.gif" />
Torque is pretty bad but I assume that from my ultra lean condtion. I'm actually suprised I didn't hurt anything. The 100 octane I was using might of saved me. According to the A/F ratio on the dyno, it's over 17 !!! <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> My AF looks like a roller coaster. The graph shows 16.5:1 at 50-65mph then goes to 13:1 at 70mph then jumps to 17:1 after 75-90mph then goes to 16:1 after that. I don't have a scanned copy yet but I'm curious why I'm running so lean??? I had my PCM updated and my run without nitrous was a lean 14:1 all the way across. My last run with my old PCM config was 12:1 (same mods). I checked my FPSS and made sure it was ajusted properly and that seams to work fine. It's not surging. I went down to a 100 shot with similar A/F ratior results. I'm running a Walbro 340 in tank pump, stock injectors. The only thing done to the engine is maf ends, lid and Magnaflow cat back. Is my new PCM config (GM) causing the problem? What else can I do?
425rwhp, 367rwtq <img border="0" title="" alt="[Frown]" src="gr_sad.gif" />
Torque is pretty bad but I assume that from my ultra lean condtion. I'm actually suprised I didn't hurt anything. The 100 octane I was using might of saved me. According to the A/F ratio on the dyno, it's over 17 !!! <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> My AF looks like a roller coaster. The graph shows 16.5:1 at 50-65mph then goes to 13:1 at 70mph then jumps to 17:1 after 75-90mph then goes to 16:1 after that. I don't have a scanned copy yet but I'm curious why I'm running so lean??? I had my PCM updated and my run without nitrous was a lean 14:1 all the way across. My last run with my old PCM config was 12:1 (same mods). I checked my FPSS and made sure it was ajusted properly and that seams to work fine. It's not surging. I went down to a 100 shot with similar A/F ratior results. I'm running a Walbro 340 in tank pump, stock injectors. The only thing done to the engine is maf ends, lid and Magnaflow cat back. Is my new PCM config (GM) causing the problem? What else can I do?
Launching!
Joined: Oct 2002
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From: Fort Collins, CO
Re: Bad day at the dyno with a 5177 Whats up Shawn! Sounds like your having fun with that nitrous kit. Im no ls1 expert but perhaps your new program is advancing timing or something weird like that to get more n/a hp which would really screw with nitrous tuning. Just a thought.
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TECH Enthusiast
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From: Highlands Ranch, CO
Re: Bad day at the dyno with a 5177 Hey Kevin. The PCM was done from someone that had access to a real GM tuner with the latest updates but now I'm having doubts. There's no programming in it.
I'll try installing my stock maf ends on too.
Thanks guys!
I'll try installing my stock maf ends on too.
Thanks guys!
