dev1360

iTrader: (1)

I had PatG spec me a cam for my LS3 Vette.

230/238 .649/.629 112+3

Cam will be ground on new "EPS extreme" intake lobes and "ET" exhaust lobes.

I trust his recommendation fully, I have had another EPS cam in my GTO that was very strong. Just looking for some more information or opinions from the group. How will that lift play with stock rockers? Any info on how these lobes are with spring reliability? I was planning on running BTR 660s with Ti retainers.

Car is:
LS3 M6 with longtubes, catless, corsa sport. DAILY DRIVER, with lots of roll racing and drag racing. A 10 overlap cam doesn't bother me on the street.

87silverbullet

iTrader: (11)

I would do the Comp trunion upgrade for peace of mind. It's too cheap to not do. Pat G and Geoff@EPS both keep spring life on their minds when designing a cam. With his EPS lobes they were designed to keep the valvetrain stable and be easy on it while still making power.

He has it on his site how his lobes differ from his old ones and others.

http://www.engpwrsys.com/tech-notes/cam-design.html

You will be fine with the BTR .660 springs. They are a good overall spring for LS cams unless you got something wild that needs more control. In that event, you can just call Brian and he can recommend something for you.

Sales@Tick

iTrader: (3)

That's more valve lift than I like to run with a stock rocker.

I am sub .635" valve lift on anything that will see over 1,000 miles a year of street use.

I'm sure the lobes have very nice ramp rates and velocity/acceleration values as Geoff has nice lobe designs. I use very similar lobes as well in a lot of applications, just not Cam Motion lobes.

dev1360

iTrader: (1)

Thanks for the input guys. I spoke with him and he offered the same intake lobe but with a 629 lift. I will be going with that in favor of more long term reliability.

He had spec'd the BTR duals with the original spec. I'm assuming he felt the pressures were sufficient.

I doubt that I will see any, if much loss in power giving up that lift. Any thoughts on that?


Thanks again guys. Like I said, Pat has been great, and I trust him fully, there just isn't a lot of info out there on the newer lobes and I'm looking for other input.

Sales@Tick

iTrader: (3)

BTR Platinums are fine for that camshaft profile if installed at 1.800". They don't coil bind until 1.09" giving .710" of an inch available valve lift.

I like to run .050-.060" from coil bind if possible in all applications. This means you could run up to .650-.660" of an inch valve lift installed at that height, assuming spring pressure is sufficient for the lobes being utilized. You will be .081" from coil bind with that amount of valve lift. You could even toss a .015" shim in there if you wanted for a 1.785" installed height. Make sure the ID of the shim matches the OD of the guide diameter though.

Sounds fine to me if you run them as such. Do you have a valve spring installed height micrometer so you can verify installed height?

dev1360

iTrader: (1)

I can verify height, but now that I am going with less lift, it will be less critical.

Thanks for the help Martin. Any input on the power loss, if any, on going with less lift? From my VERY limited knowledge, it may actually help keep the air velocity up.

Sales@Tick

iTrader: (3)

Velocity increases as valve lift increases in the port.

As long as the port can continue to at least maintain flow at that amount of valve lift, velocity will continue to maintain a localized air speed as long as the port does not stall out. If the port can continue to gain flow as lift increases, velocity will continue to increase.