LB7: Rod limits
- Thread starter motoking_1990
- Start date
Or rather I should ask, what is the highest mph you ever trapped regardless of ET?
I would say the reasonable window is 600rwhp +/- 10hp, depending on things like wind and bugs hitting the windshield
:thumb:
Drivers bank was 390, 395, 400, 385 pass bank was 390, 400, 405, 395. Used a harbor freight tester when engine was warm. Balance rates are also -+ 1.0. Did the test last weekend. I thought those numbers looked pretty good but I also don't drive it like I stole it.
I would like to know the differece between lbz and lb7 rod strengths as well.
My truck has been at or above 600 since 2009. Right at 100000 miles on that configuration. For the 85000 of those miles I was relentless on ole girl. I started to lighten up the last 15000 after I lifted it. But I am always prepared to pay to play. I dont anyone has a definitive answer mostly just luck and lies
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My truck has been at or above 600 since 2009. Right at 100000 miles on that configuration. For the 85000 of those miles I was relentless on ole girl. I started to lighten up the last 15000 after I lifted it. But I am always prepared to pay to play. I dont anyone has a definitive answer mostly just luck and lies
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400 is about what a lly/lb7 make new, 380 is what mine made with lower compression pistons and not quite broke in fully. 330-350 and lower and your on bent rods. 250-270 puts you in pistons hitting crank and lots of white smoke, 270+ puts you in the haze territory. this is all based off my motor and others ive read about.
inbetween 350 and 380 is "iffy". a quick shot of oil in the cyl and a rerun of the compression test, then a leak down will tell you if really is rods starting to go, rings worn, or a valve not fully seating.
You are borderline so I would expect your weakest rod/rods to slowly get shorter as you run more of the max effort passes. If you stay at that power level they may just shorten a little bit and stay there.
Beware though that once even one is bent it becomes much easier to bend it further, so even adding +50hp could devastate said rods.
Looks like my #6 rod is the shortest with the 385psi of compression. My 12.4 tune is a 2450us on 40% and my stock cp3 holds rail at 22.5k I have a 2600us written but haven't ran it. Most of the time I run on my 2250us.
This is very good information. Looks like I need a compression tester. I have one for spark plugs but not one to go into the glow plug hole.
I think I am going to to buy a spare engine and start building it. That sounds like my best bet. I see a lot of people parting out trucks on here, so finding one shouldn't be too hard.
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Alrighty here are my compression test results.... 05 lly, grade c gaskets, s472, 30% injectors, efi, always ran on my biggest tune and ran hard every single time I drive it. 161,000 miles. Towed a goose neck it's whole previous life and the last 25,000 miles i have owned it, it has been abused. What do you guys think?
#1: 360 psi
#2: 370 psi
#3: 360 psi
#4: 360 psi
#5: 390 psi
#6: 360 psi
#7: 360 psi
#8: 380 psi
#1: 360 psi
#2: 370 psi
#3: 360 psi
#4: 360 psi
#5: 390 psi
#6: 360 psi
#7: 360 psi
#8: 380 psi
According to chevy1925 some of them are kinda low possibly starting to bend.
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