Thread: dyno sheet for xp cam build

Originally Posted by GTPpower

Both runs are on a 3.0 pulley. It was just way colder in the first video. Obviously, you can see that the valves floated.

I can see the blip you mean and that shouldn't have happened but to say they went away with the 130s in that video comparison there's obviously a boost factor at play, and I would have liked to have seen a scan with a wideband AFR to see other factors were at play.

I'm not trying to be a dick about it, don't get my intention wrong, but as mentioned I have a lot of first hand positive experience using LS6 springs and a lot of success, so someone telling me now that I was doing something wrong I have difficulty with without some very definitive rationale. You've given the best counter arguement so I'd like to know more.

Originally Posted by Overkill

I can see the blip you mean and that shouldn't have happened but to say they went away with the 130s in that video comparison there's obviously a boost factor at play, and I would have liked to have seen a scan with a wideband AFR to see other factors were at play.

I'm not trying to be a dick about it, don't get my intention wrong, but as mentioned I have a lot of first hand positive experience using LS6 springs and a lot of success, so someone telling me now that I was doing something wrong I have difficulty with without some very definitive rationale. You've given the best counter arguement so I'd like to know more.

It's not only me though. Lots of people have experienced the same thing I have. All the great engine builders will always recommend 130's. Tischler, PRJ, Janice, etc.

Originally Posted by GTPpower

It's not only me though. Lots of people have experienced the same thing I have.

Any links or names?

All the great engine builders will always recommend 130's. Tischler, PRJ, Janice, etc.

PRJ would put 130s on anything, he and I had our fair share of bantering 10+ years ago. I can understand a motor shop like Tischler suggesting 130s for good measure but I don't know how many 3800s they actually set up from scratch or their long term results.

Again my concern on the 130#s is quality, and timing chain life. I'd consider the PAC 1218 130#s, they have a good rep, but you'd never see CompCam 130s in my engine again due to failure issues, and Manley springs for the same reason. I don't think there's any timing chain on the market currently that you can anticipate will last more than a few short years, which 130s don't help with. I had extensive experience with GM LS6 springs without these issues, on 2.x pulley 12-13psi 6200rpm shift point cam and cam/rocker packages, no boost spike/valve float/trouble making horsepower issues, I never had a spring failure, I trusted the quality, I never saw a need to go for anything else. When I switched to Vortec valves, I ran 110# factory LS7 springs, again not an issue, they worked great, and I trusted the GM factory quality.