Well.. To help add some proof to the recent posting of people wanting more lsa / less lsa.. Here's some proof of what a wider LSA does for your HP numbers.

Both graphs are from my car - a decently modded +.040 LT1 w/ homeported heads.

The red graph line is from my previous 230/236 .598/.608 110LSA "EX" grind cam. The blue graph is my current 233/242 .571/.577 114LSA cam. It's also an "EX" grind cam. I was hoping that the increase in duration would help keep my peak RPM's closer to 6500 like they were previously, but w/ the nose dive at 6200, it looks like a rear gear change will be needed in order to run anything close to my ET's / MPH from last year. Especially on nitrous.

I'm yet to get any dyno numbers on nitrous, but am hoping that the numbers are at least more comparable than the N/A numbers. But now I have to get used to the fact that my car is now ~ "sometimes fast - but most of the time, not " .

FWIW, both of these numbers aren't my "personal bests" for each cam.. But merely a correction factor of 1.00 on the dynojet, w/ similar temps and BP and such. When I reset the PCM on the 233/242 tune, my car picked up an additional ~10rwhp/10rwtq across the band, and I also fattened it up a little bit. But I can't find that graph.


CC 230/236 vs CC 233/242..

 

how about a 112LSA comparison now? lol jk...Nice numbers and good comparison

 

LOL! I do have a CC306 dyno from way back ... But, I'm yet to run the same ET's I ran w/ that.. And now that I've made my car NHRA Legal, along w/ adding a stereo and other goodies - it's about 200lbs heavier. So it's kinda hard for a 3720lb car to run worth a flip.. Especially w/ only 365ish rwhp

Hmm.. Guess I need to see how she runs on nitrous before finding a cliff.. LOL

 

Shawn, judging by the lift numbers of your old cam, I'm guessing they were in fact High Lift Magnum lobes--not XE lobes. If this is so, it could also be a factor that allowed the old cam to rev with a flat power curve from 5900-6500 while the new XE cam could be floating the valves at 6200. What are the advertised durations for each cam?

What springs are you running and what seat pressures are they set up for?

Just a wild theory....

 

I know I'm not floating valves - I had to get my valvetrain sorted out w/ the previous cam to even make it rev past 6k. Stock lifters, Comp 987's, tit. retainers and a rev kit wouldn't cut - but it still ran 8.0's short shifting @ 5k rpms , so I went w/ some CM EX618's and some Comp R lifters.. I could then rev it out to 7k.

As far as adv. duration, my old cam is a good "in-between" from what I have now.. Literally.. LOL.. It was a 286/290.. and the current one is a 283/293

 

The new cam has much steeper ramps between .006 and .050. This might cause it to bounce the valves on the seats at a lower RPM than the old cam did with the same springs, valves, retainers, etc.

But I'm just thinking out loud here and I'm certainly a Newbie Retard when it comes to this valvetrain stuff so take that FWIW. Just a thought.

 

My valve springs are pretty stiff.. So, I doubt that's happening. If anything they're too stiff for my application, considering the lift isn't as high.. DOH!

160/400.. Enough pressure for a small SR cam.

 

There is also a LSA comparison in the May CHP.
383 SBC Smeding crate motor
215/224 106lsa
215/224 114lsa

-The 106 had 20 more lbft from 2500-3200
-4500-5000 rpms they were very similar with the edge going to the 106
-The 114 peaked around 5100, and the 106 around 5200
-After 5400 the 114 dominated because the 106 took a bombdive, but that was significantly past pk hp and a realistic shift point anyways.

Take this only for what it is though, with a much larger cam and excessive overlap the results may have been reversed. The wider LSA could have helped low end torque by not allowing as much reversion, but because of the small durations for a 383 even on a 106lsa excessive overlap and reversion wasn't a problem.

-brent

 

Nice to see real numbers - I expected to see the 110 cam outperform the 114 - still after the PCM reset they are very close.

I'd expect the new cam to be a bit better on nitrous