Where did I go wrong?
#22
12 Second Truck Club
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Disclaimer: The following is JMO. I am no expert, didn't stay at a Holliday Inn Express last night, nor have I ever had a turbo vehicle. I just read a lot and have formed my own opinions. I will not get upset if someone proves me wrong, I am just learning here. With that being said. LOL
I know the truck manifold is not totally to blame, cars are prone to poping #7 too. It's the front inlet design all together that's the problem..... We probably wouldn't have to push the AFR down to mid 11's under boost if the rear cylinders didn't lean out so much. It would be interesting to know what the AFR of each cylinder was. I'd be willing to bet that the rear cylinders are seeing a more lean condition than the front cylinders just due to the flow of air in the manifold. If you richen up enough to keep #7 alive, your front cylinders are most likely way richer than they actually need to be..
I know the truck manifold is not totally to blame, cars are prone to poping #7 too. It's the front inlet design all together that's the problem..... We probably wouldn't have to push the AFR down to mid 11's under boost if the rear cylinders didn't lean out so much. It would be interesting to know what the AFR of each cylinder was. I'd be willing to bet that the rear cylinders are seeing a more lean condition than the front cylinders just due to the flow of air in the manifold. If you richen up enough to keep #7 alive, your front cylinders are most likely way richer than they actually need to be..
#24
Disclaimer: The following is JMO. I am no expert, didn't stay at a Holliday Inn Express last night, nor have I ever had a turbo vehicle. I just read a lot and have formed my own opinions. I will not get upset if someone proves me wrong, I am just learning here. With that being said. LOL
I know the truck manifold is not totally to blame, cars are prone to poping #7 too. It's the front inlet design all together that's the problem..... We probably wouldn't have to push the AFR down to mid 11's under boost if the rear cylinders didn't lean out so much. It would be interesting to know what the AFR of each cylinder was. I'd be willing to bet that the rear cylinders are seeing a more lean condition than the front cylinders just due to the flow of air in the manifold. If you richen up enough to keep #7 alive, your front cylinders are most likely way richer than they actually need to be..
I know the truck manifold is not totally to blame, cars are prone to poping #7 too. It's the front inlet design all together that's the problem..... We probably wouldn't have to push the AFR down to mid 11's under boost if the rear cylinders didn't lean out so much. It would be interesting to know what the AFR of each cylinder was. I'd be willing to bet that the rear cylinders are seeing a more lean condition than the front cylinders just due to the flow of air in the manifold. If you richen up enough to keep #7 alive, your front cylinders are most likely way richer than they actually need to be..
#26
If u have fragged internal parts, that could limit. If it's ok, somewhere there is a bottleneck. Back when the TPI's were out, they ran out of breathe @ a certain RPM. I'm not gettin into manifold design, yada yada, but it was known GM designed that piece for the 305 rather than retool for the 350. They choked it. Or like a 112 on a 6L. Limits can be found. I'm w/ the others, pull the head. If u don't, & ****'s in pieces, it'll just lead to more damage. At least that way, you'll know what u r up against. Repair, build the snot out of your existing 5.3, or go build a 6L. Pay now or pay later.
#27
TECH Apprentice
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If #7 were being chocked by the manifold...wouldn't it cause this cylinder to run rich? All cylinders should have the same injector PWM for fueling at any given RPM. FWIW I have spoken to some experienced LS1 mechanics about issues with #7 popping ringlands and they were of the opinion that inadequate coolant flow around #7 is the cause of problems with this cylinder. Not trying to start a pissing match, just trying to throw another probable cause out there. I'm here to be educated and share any and all information concerning this problem. For anyone on the edge and and pushing the limits of this engine, piston #7 has always been a concern.
Last edited by Doobie; 05-01-2008 at 12:18 PM.
#29
Launching!
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If u have fragged internal parts, that could limit. If it's ok, somewhere there is a bottleneck. Back when the TPI's were out, they ran out of breathe @ a certain RPM. I'm not gettin into manifold design, yada yada, but it was known GM designed that piece for the 305 rather than retool for the 350. They choked it. Or like a 112 on a 6L. Limits can be found. I'm w/ the others, pull the head. If u don't, & ****'s in pieces, it'll just lead to more damage. At least that way, you'll know what u r up against. Repair, build the snot out of your existing 5.3, or go build a 6L. Pay now or pay later.
#30
I AM A MOTHERF*CKER
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If #7 were being chocked by the manifold...wouldn't it cause this cylinder to run rich? All cylinders should have the same injector PWM for fueling at any given RPM. FWIW I have spoken to some experienced LS1 mechanics about issues with #7 popping ringlands and they were of the opinion that inadequate coolant flow around #7 is the cause of problems with this cylinder. Not trying to start a pissing match, just trying to throw another probable cause out there. I'm here to be educated and share any and all information concerning this problem. For anyone on the edge and and pushing the limits of this engine, piston #7 has always been a concern.