Initial results of my AS stage 2.5 5.3 heads
09-09-2004, 07:54 PM
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Initial results of my AS stage 2.5 5.3 heads The car is 02 Z06, mods are a Halltech stinger, 30lb SVO's, Kooks headers and x-pipe, Borla stingers, UD pulley and a comp cams 228/230 .571/.573 112 cam shaft. Before the dyno 425/400, after 448/410. I made a bunch of pulls and the car kept spitting out black smoke-showing it's rich however the wideband kept showing 12.8 no matter how much i leaned it out. Then I backed out timing-tried 22 total versus 24, car lost almost 10 horsepower! Now i didn't want to add anymore timing because the car is now at 11.1 verus 10.5 stock. Then the dyno broke. I talked to Jay and he wasn't happy with the results-he said the heads need way more timing! He told me to try 28 to 30 degrees and i should see a gain of at least 15 more horsepower! His reasoning was the LS6 chamber doesn't take to timing as well as the 5.3 chamber and all the new 5.3 castings run at least 28 to 30 degrees with no problem. It makes sense now since I lost 10 horsepower from only 2 degrees! I
was pretty happy but now i can't wait to get back on the dyno. I've always dynoed at the same dyno but i've heard from a few people that the wideband doesn't seem to be working right and just last week the dyno broke down again. As soon as the dyno's up and running properly i'll be back to see if i can hit 460. As far as the heads go they look awesome! The quality the hand porting is all top notch-they work!
was pretty happy but now i can't wait to get back on the dyno. I've always dynoed at the same dyno but i've heard from a few people that the wideband doesn't seem to be working right and just last week the dyno broke down again. As soon as the dyno's up and running properly i'll be back to see if i can hit 460. As far as the heads go they look awesome! The quality the hand porting is all top notch-they work!
09-09-2004, 10:22 PM
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No bro, no cats and the TB is stock and the factory issue LS6 intake. The valves are 2.02/1.57, I thought they were supposed to be 2.05 intakes but Jay said that wet flow testing showed the 2.02 valve had more swirl.
09-10-2004, 02:48 PM
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Nice numbers!
We found the same thing when I went from 5.3's to these LS6 heads. LS6 liked less timing.
24 degrees was the sweet spot for us on LS6 heads. (466RWHP and 44X RWTQ through single cutout)
We found the same thing when I went from 5.3's to these LS6 heads. LS6 liked less timing.
24 degrees was the sweet spot for us on LS6 heads. (466RWHP and 44X RWTQ through single cutout)
