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Comp LSR lobes

General engine tech -- Drag Racing to Circle Track

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CGT
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Re: Comp LSR lobes

Post by CGT »

turbo camino wrote: Wed Oct 14, 2020 8:31 pm Can somebody explain the Comp custom grind format for me? The catalog seems to be missing the part that gives the prefixes for each engine family. I'm able to figure out that CB is BBC and CS is SBC from the examples, but the others are a mystery. I know the core will be 54-000-11 and lobes are 13093 intake & 13172 exhaust. (that's a slightly shorter LSL intake lobe and a supposedly quieter/slower closing LXL exhaust.)
I have always ordered them with just the information you listed along with LCA and advance or retard. It doesn't seem that the prefixes and suffixes apply to LS.
turbo camino
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Re: Comp LSR lobes

Post by turbo camino »

Do I need to keep open pressure under 400 with stock rockers, or is that internet myth?

The recommended Comp 26926 (505lb-in) are 146 seat/449 open. PAC 1904 (370lb-in) are 150 seat/372 open. 6000 RPM max. Stock rockers w/ CHE bushings. 106g intake/97g exhaust valves.

edit:
PAC-1905: 392lb-in 160 seat/395 open
COMP 7228: 438lb-in 136 seat/399 open
DON'T PANIC
turbo camino
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Re: Comp LSR lobes

Post by turbo camino »

As if choosing a cam isn't creating enough angst (I have had a few dreams involving valve springs), reality has presented another option: do nothing. (for now)

DOD is disabled in the tune as a preventative measure so it's not gonna fail if it never gets used. Engine runs nice. Even with stock everything, just tuning has taken it from stock 280hp/305tq, to 375hp/390tq. Peak tq is now 200 RPM lower than stock, and peak HP is happening 300 RPM higher. Fuel mileage has improved by about 1/2 a point. Stock air intake tube and filter, stock iron manifolds, stock muffler even. The injectors are over 80% duty cycle already.
DON'T PANIC
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