HKS 280's

[Warrtalon]

If you don't have any idea of where to set your cam gears, then trying to randomly "dial them in" on a dyno is going to be fruitless. There are so many combinations of settings, but VERY few actually work, and even fewer work the way you want them to. YOu need to go in with settings already planned based off what others have already proven to work, imo.

[turbolarry]

Since your going to the dyno this weekend, your set. The only way to do it right is on a dyno and not just going with what people tell you. Your just going to have to do several pulls to see what you like and what works for your car. There's nothing "random" about it. You make an adjustment, make a pull then look at the chart. How did it effect the powerband? You want that power scooted up or down. It comes down to lot's of pulls and seeing cause and effect.

"If you have good cams but want to move the powerband around a bit, here are some rules of thumb."

"-Retarding both cams will move the powerband up a few hundred RPM. On the EVO with the HKS 272 cams, a popular setup is to use 2 degrees retarded for both cams. Since both cams are moved evenly, the overlap doesn't change, only the lobe centers change, causing the valves to open and close later. In this case, the cams spin half as fast as the crank, so 2 degrees at the cam is 4 degrees at the crank. The crank will be an additional 4 degrees through its rotation before the valves open/close."

"-Advancing the Intake cam, and Retarding the Exhaust cam will open up the overlap a bit. This allows the cylinder to fill sooner due to the intake valve opening sooner, which can sometimes be advantageous in a turbocharged engine. This also helps to improve the idle quality since the Intake cam has a larger impact on the idle than the Exhaust cam does. Or, the exhaust cam can be retarded more than the intake cam, as in a -1 -4 setup. Both cams are retarded in this situation, but the exhaust cam is moved more, increasing the overlap."

"Ultimately this is one of those cases where a dyno comes in real handy. You move the cams around until you find the right combination. Unfortunately theory only gets you so far, and practice makes perfect..."
http://www.socalevo.net/index.php?op...&topic=12859.0

[Warrtalon]

If he has all day to test every combination without even a starting point, then yeah, but if he only has an hour or two, then it's best to know some of the settings that work best and go from there, imo.

I consider it random if the individual is not educated on cam gear settings and has no idea where to start nor an idea of how to adjust according to that is seen on the graph.

[ghoonk]

Since I'll be doing the dyno at a local tuning shop, I'm asked a friend to check with them if they have experience tuning cam gears and what it costs. Then I will try various combinations as suggested and pick from the most appropriate map.

Warr, I used DLL to generate a power graph and wanted your 2 cents on this. Looking at my mods, is this a good tune or have you, in your experience, seen better and can suggest what else can be done. My cam gears are set to -1 in/-2 ex, and if this is as good as you think it's going to get with my mods, then I won't bother with the cam gear tuning.

[Warrtalon]

Where's the file?

[ghoonk]

My bad, here they are

-2 intake / -1 exhaust, HKS 272 cams, HKS cam gears



and here's the chart for -4 intake / -1 exhaust, same setup



For street driving and short track, I'm going to test +1 intake / -1 exhaust (as recommended by TedB from EvoM), and changing over to -4 intake / -1 exhaust for track days with long straights and long sweepers.

[Warrtalon]

FWIW, those torque curves are way off from a real dyno, so keep that in mind. It's peaking about 1000rpm late.