pac 1218 with boost
pac 1218 with boost i got some pac 1218s in my shop that i had plans to run on my boosted 5.3 build. shifting at 7k with at least 20 psi through an s485. camshaft is the summit stage 2 boost cam. stock rockers, morel lifters, heads are stock as well. Think these springs will hold up or should i go to the pac 1219s. thanks
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Joined: Dec 2019
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Stock Gen 3 4.8 long block other than 226/232 .578/.587 110 LSA cam and PAC1218s.
Quad 50mm China turbos.
Runs 9s on single digit boost, but the RPM sure does help.
I sold the entire setup as a complete pull-out. I'm actually pulling it out of the car tonight.
Quad 50mm China turbos.
Runs 9s on single digit boost, but the RPM sure does help.
I sold the entire setup as a complete pull-out. I'm actually pulling it out of the car tonight.
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Joined: Nov 2018
Posts: 467
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TECH Fanatic
Joined: Dec 2019
Posts: 1,129
Likes: 478
I could have went 9.50 or better on 9 PSI with a 4.8, but the 3.07 gear and torque converter specced for a 1200 HP 5.3 made the first 330 feet pretty lazy.
I did manage to go 5.8x on 15 PSI in the 1/8th despite not picking anything at all for the first 120 feet or so over the 6.30 I ran on 9 PSI.
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I dont' understand why some get away with crazy RPM on mild spring and others do not. I had roughly 60psi worth of back pressure on my PAC 1218's. From what all the "CAM Companies" say you have to add that force in for the the spring pressure to overcome. (then you have to calculate the surface area of the valve and do a bunch of math I Have no idea how to do as well)
Yet I ran 26lbs of boost to 6800 or so no problem on a 5.3. (ls9 cam)
Yet I ran 26lbs of boost to 6800 or so no problem on a 5.3. (ls9 cam)
I dont' understand why some get away with crazy RPM on mild spring and others do not. I had roughly 60psi worth of back pressure on my PAC 1218's. From what all the "CAM Companies" say you have to add that force in for the the spring pressure to overcome. (then you have to calculate the surface area of the valve and do a bunch of math I Have no idea how to do as well)
Yet I ran 26lbs of boost to 6800 or so no problem on a 5.3. (ls9 cam)
Yet I ran 26lbs of boost to 6800 or so no problem on a 5.3. (ls9 cam)
because I’m debating on going with Tick’s dual spring set up good for .660 lift.