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I just had my injectors flowed and am going to put the one with the richest offset in cylinder #7. Are there other cylinders that are known for going lean? Does the port type matter? (i.e. cathedral, rectangular, etc)?
7 & 8 have been known for it, but part of it could be engine temps the rear cylinders are the hottest as well. Why do 7 & 8 still the ones that get hurt when ppl turn the intake manifolds around for intercooled race cars? GL!
We know they more commonly fail first on stock engines/pistons. But that's about it, and is not the same as a claim of running lean.
Heat is the more likely reason as proven by those who reverse the intake. OEM thermostats which run seriously hot, combined with weak pistons for boost, high compression etc just dont make good partners for boosted setups
Last edited by stevieturbo; 05-24-2017 at 05:48 AM.
We know they more commonly fail first on stock engines/pistons. But that's about it, and is not the same as a claim of running lean.
Heat is the more likely reason as proven by those who reverse the intake. OEM thermostats which run seriously hot, combined with weak pistons for boost, high compression etc just dont make good partners for boosted setups
Yeah kind of my point, and I mentioned 7 & 8, as being damaged more that the others. But yeah not necessarily lean.
from what I can tell I think it's cooling issues too. I feel better on my setup running the cooling tubes to try and help with this off the back cylinders. At standing mile and 1/2 mile I've heard of guys putting in one step colder plug in those back cylinders too but I just put my two highest flowing injectors on those too and now when I pull the plugs they look the same as the others at least.
7 & 8 have been known for it, but part of it could be engine temps the rear cylinders are the hottest as well. Why do 7 & 8 still the ones that get hurt when ppl turn the intake manifolds around for intercooled race cars? GL!
Thanks! I agree, I should have also mentioned the issue with heat dissipation which I've also been hearing about lately for semi-high powered LS engines. Not sure if running those cylinders slightly richer might alleviate some of that problem by placing the fatter injectors in 7 & 8?
Originally Posted by stevieturbo
We know this ?
We know they more commonly fail first on stock engines/pistons. But that's about it, and is not the same as a claim of running lean.
Heat is the more likely reason as proven by those who reverse the intake. OEM thermostats which run seriously hot, combined with weak pistons for boost, high compression etc just dont make good partners for boosted setups
Interesting, I always thought that besides the power limitations of the stock block, running lean with #7 was also an issue.
Originally Posted by Turbo-Geist
On both of the engines failures I've witnessed, neither one of them involved damage to #7. Also, the LS1 rod bolts will handle more than 500hp.
I think we can both agree that engines can fail for multitudes of reasons, I was just concentrating on the #7 cylinder.
Originally Posted by neverstop
from what I can tell I think it's cooling issues too. I feel better on my setup running the cooling tubes to try and help with this off the back cylinders. At standing mile and 1/2 mile I've heard of guys putting in one step colder plug in those back cylinders too but I just put my two highest flowing injectors on those too and now when I pull the plugs they look the same as the others at least.
Sounds like good advise, any links of the best cooling tube solution(s)?
I heard Kurt Urban tested it with the intake both ways and the same cylinders still had problems. That is why he sells the 4 corner steam tubes. I also have read the C5R racing program Stopped runing the rear steam tubes because it was causing its own issues and that's why the newer engines just run the fronts. I think in order to keep air pockets out of the cylinders they blocked the rears off.
I went with the expensive Kurt Urban steam tube setup, because Kurt Urban. and his design made sense to me. I would think any of the steam tube kits are better than nothing imo though
Yeah I used to run the truck crossover in the rear and run the line up to the radiator. But another thing is the factory runs series cooling because it heats up fast for emissions, not because its best. Nascar doesn't run it like that, they run Parallel cooling etc... But dry decking the head and block works too lol!
I'm with Kurt. The series cooling that GM decided to do with the LS isn't acceptable. I worked with H Squared racing engines to convert to parallel cooling to help with cooling issues that cause localized boiling within. That's an issue that becomes a bigger and bigger deal with increased power. I've got lines coming out the back of the heads too for a return path. Once the engine sees a certain amount of boost, I'm activating an electric water pump that pulls from the colder side of the radiator and pushes water across the exhaust side of the chambers.
I'm with Kurt. The series cooling that GM decided to do with the LS isn't acceptable. I worked with H Squared racing engines to convert to parallel cooling to help with cooling issues that cause localized boiling within. That's an issue that becomes a bigger and bigger deal with increased power. I've got lines coming out the back of the heads too for a return path. Once the engine sees a certain amount of boost, I'm activating an electric water pump that pulls from the colder side of the radiator and pushes water across the exhaust side of the chambers.
You putting the blower back on or is that an older pic?
05-23-2017, 07:13 PM
We all know that #7 goes lean first, but
