imho you had alot of things not working in your favor, but for weight of vehicle it ran decently well

 

Solid or hydraulic roller cam? Seems to be almost a toss up.... solids may allow for some tweaking?

 

BDS states that they have found 110 LSA to provide the best power on gasoline. https://www.blowerdriveservice.com/c...lications.html

Here's their cam spec page

 

I gotta be honest the 110LSA comment as a blanket statement makes me not really trust their opinion.

 

To me that statement is very generic and pointless by them, the LSA by itself does little to determine total valve event picture. You can get the same amount of overlap via endless ways.

 

Seems like by maintaining a fixed LSA they are wanting to have increased overlap as lift and duration increases. Just looking at the big block grinds listed, overlap ranges from -2.5 to +35.

Here is an interesting comparison.

Blower cam: 0.617/0.595 231/248 120 LSA -0.5 overlap
768 HP 683 TQ

NA cam: 0.617/0.624 231/247 113 LSA +13 overlap
758 HP 681 TQ

**The motor was only run up to 6200 on each pull.

The NA cam made more power to 3900 RPM, was even to 5400, then lost out to the blower cam above that. Would have liked to see the same exhaust lift on the blower cam.

Seems that many consider a "blower cam" one with minimal or -ve overlap, while BDS does not subscribe to that.

 

Was it the same blower and engine and only the came changed? Where are you getting the data from?

If you can get the same results with slightly less overlap why not do it? You car or truck will run night and day better. While I agree that some overlap has big benefits if your blower is capable enough and you are moving enough air, I think like anything else there is a law of diminishing returns. Frankly even negative returns as you kill your drivability. And much more importantly than overlap, the reason cam #2 didnt perform at upper RPM ranges is the intake close and exhaust open were much closer to TDC.

What most of you seem to completely disregard is that its not LSA that drives your cam choice. Pick your valve events. From there duration, LSA, and ICL all fall into place. LSA on its own is a VERY meaningless number. I can't stress that enough.

 

It was the article linked above. Click on "interesting comparison". Same motor just swapped cams. They also tested the LSA and LS9 cams.

 

What about reversion at low RPM/non-boost with a runnerless intake? I recall Magnacharger stating that GM tested this and found no negative effect on engine operation, but GM wouldn't use a cam that has any overlap.

 

If I am calculating correctly...........

Current cam 226/236 on 114+4
Intake open 4* BTDC
Intake close 44* ABDC
Exhaust open 56* BBDC
Exhaust close 0* (TDC)
DCR 8.33:1
Boost CR 19.66:1

New recommendation 246/260 on 112 with similar gross lift, but solid roller grind
Intake open 11* BTDC
Intake close 55* ABDC
Exhaust open 62* BBDC
Exhaust close 18* ATDC
DCR 7.85:1
Boost CR 18.53:1