Thanks 68forumla, so this is something that has always confused me, since the DynoSim cam calculator seemed like it automatically filled in the intake and exhaust centerline, except it did it backwards from what you said for the BTR cam:

The program acts like you have to have intake centerline as a input variable and it greys out exhaust centerline but then it does finicky stuff when you try to edit the intake centerline, which I feel is correct because if you didn't input the intake centerline you don't know how far the advance/retard could be shifted right? So how did you know the intake centerline is 110 degrees? I would assume you took the 111 LSA and subtracted 1 degree for the advance and get 110, I mean I know you can find the exhaust or intake centerline by adding or subtracting the LSA, but you still have to know at least one of them to start with?

 

You have to know at least 2 of the 3 (LSA/ICL/ECL) to get the 3rd. If they only tell you LSA (some cam vendors like to keep their specs very secret), you're completely guessing.

Many vendors list LSA + Advance (or Retard). So if LSA = X and Advance =Y, then ICL = X - Y
If the factory cam is ground retarded (114 - 2), then ICL = 114 - (-2) = 116, ECL = 112
Note: The early version of the BTR Torque cam was also retarded (111-1) so the ICL was 112 as you show. But a couple years ago, they released a new version which is 1* advance, so ICL is now 110).

LSA = average of ICL and ECL. So LSA = (ICL+ECL)/2.

Play with this calculator, it'll help you understand: https://www.summitracing.com/newsand...ing-calculator

Another thing to mention, a lot of head data goes from 0.500 to .600. If you only have these two inputs, the sim will linearly interpolate in between 0.500" and 0.600" head flow values when you put in the cam lift. But many factory heads peak around .550 to .570". And head flow generally behaves as a 2nd order polynomial curve. So if you can find head data @ .550, it will improve the accuracy quite a bit for cams >.500" lift. Especially the smaller duration camshafts; this can not only impact peak power, but low-end torque as well.

 

 

I almost feel like this thread can be stickied for the 4.8 guys now. To get more low end torque & HP from your 4.8 you need to do one of 2 things. Add boost or get more cubes. Nitrous is an option to get more down low in a drag application but this question always seems to come from the guys looking for pulling power. I think this even applies to the 5.3 and 6.0. Once upon a time I got a 212/218 cam for my 6.0 hoping for more low end grunt. After research i sold the cam off and found a supercharger to put on the engine.

 

Ive got a truck here with a stock 4.8. I'll dyno it and just what kinda power It has from 1000rpms and up.
got another 4.8 we are doing a cam in and ill be able to dyno it also to do a fair comparison

 

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We're WAITING .....

 

Waiting on transmission parts still...

 

What turbo were you running?

 

S475/83 1.10A/R T4 6-8psi for DD and towing.
8psi at 2000 rpms it would chug on along and whistle.
Stock muffler and stock airbox.

 

Thanks. Thats just the type of boost im looking for. Ideally I would like to get that kind of boost with twin turbos rather than a single.