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My first guess would have been valve float like many others mentioned. I have seen that same condition at work though due to a slipping 4L60E. The tune show's you locking the converter at 87MPH. That could create a problem with a 60E. If you make a pull with the converter locked you want to lock it early so that when you go wide open it is already locked and doesn't unlock. Does it feel like the dyno show's on the street? Curious, why a TR8 with such low cylinder pressure?
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2006 Silverado RCSB 2wd: L59, GT4, G80, Z82, 41U. Outlaw CAI, Corsa catback, Zippy programming, LPE 160º thermostat, Precision Industries TBTC, Detroit Locker, Comp Cams 222º/224º .566"/.568" 112LSA, LS6 springs, flex fuel. 14.048@97.09 2.076 60' in full street trim on the 20's.
Wife's: 2002 Tahoe 2wd, LQ4, 4L60E, 3.42, Gov-Lock, 862 heads milled .015 with 2" Ferrara stainless intake valves, LS6 springs, TR224 112LSA, 160º thermostat, Zippy Programming, flex fuel.
Valve float would be my guess. How are your springs set up?
5.3L with 317 heads?? Really?? The combustion chamber has to be hanging over the cylinder bore pretty badly!
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[SIGPIC][/SIGPIC]
Quote:
Originally Posted by John Lingenfelter
The world's best cam combined with a poor set of heads will produce an engine that's a dog. But bolt on a set of great heads even with a poor cam, and that engine will still make great power.
My first guess would have been valve float like many others mentioned. I have seen that same condition at work though due to a slipping 4L60E. The tune show's you locking the converter at 87MPH. That could create a problem with a 60E. If you make a pull with the converter locked you want to lock it early so that when you go wide open it is already locked and doesn't unlock. Does it feel like the dyno show's on the street? Curious, why a TR8 with such low cylinder pressure?
It does feel on the street like it shows on the dyno... pulls really hard to 5500 then almost stops pulling hard lol
I switched to autolite 103's (same as tr6's) and it didn't help...
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***Budget Boost 5.3L in progress! Pullout 5.3, 317 heads, ls6 intake, 02 ZO6 cam, hardened pushrods, PRC dual springs, FMIC, 12-15* timming, 12-15psi boost.... GOAL 600HP! CHECK IT OUT HERE: http://www.ls1tech.com/forums/forced...old-turbo.html
Valve float would be my guess. How are your springs set up?
5.3L with 317 heads?? Really?? The combustion chamber has to be hanging over the cylinder bore pretty badly!
I have TSP dual valve springs with titanium retainers good to .660 lift... they should be more than enough, they have less than 8000 miles on them also.....
There are other guys pushing over 600 with 317's...
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***Budget Boost 5.3L in progress! Pullout 5.3, 317 heads, ls6 intake, 02 ZO6 cam, hardened pushrods, PRC dual springs, FMIC, 12-15* timming, 12-15psi boost.... GOAL 600HP! CHECK IT OUT HERE: http://www.ls1tech.com/forums/forced...old-turbo.html
The 317's aren't the problem. They are part of the reason you didn't make more power since 8.5:1 compression is great if you're going for 30psi, but at less than 20psi you'd have made more power with the stock heads and stock compression. Don't take that as an insulting comment, I admire your build. Going for big power for little money is a fun project. In your tune I see you took alot of fuel out at the higher rpm, do you have a chart of your AFR? I see that some of the boost begins to flutter during the rpm that this is happening. Is it possible that you have an intake leak? You could try to open the wastegate fully and pull the tube off of the throttle body to see if it does the same on an N/A pull. If it does that will narrow alot down. Make sure to post up as you're working on it though as I am curious as to what you're finding.
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2006 Silverado RCSB 2wd: L59, GT4, G80, Z82, 41U. Outlaw CAI, Corsa catback, Zippy programming, LPE 160º thermostat, Precision Industries TBTC, Detroit Locker, Comp Cams 222º/224º .566"/.568" 112LSA, LS6 springs, flex fuel. 14.048@97.09 2.076 60' in full street trim on the 20's.
Wife's: 2002 Tahoe 2wd, LQ4, 4L60E, 3.42, Gov-Lock, 862 heads milled .015 with 2" Ferrara stainless intake valves, LS6 springs, TR224 112LSA, 160º thermostat, Zippy Programming, flex fuel.
528HP 491TQ.... BUT have you ever seen a graph like this!?!
