Here are the specs on a set of cams I was looking at.

Rocker Ratio
1.55 intake/exhaust

Intake
Duration: 288
Lift: .490"
Clearance: .006"

Exhaust
Duration: 266
Lift: .454"
Clearance: .008"

<u>0.50" Tappet Lift Specs</u>
Intake
Duration: 250
Lobe Lift: .316"
Opens: 25 BTC
Closes 45 ABC

Exhaust
Duration 232
Lobe Lift: .293"
Opens: 44 BBC
Closes: 8 ATC

Lobe Separations: 104
Intake Centerline: 100

Now I am not an expert here, but does the advertised duration not seem a little low? The stock advertised duration on my stock B18C1 cams is 290 & 292 vs 288 & 266. However the lift on the stock bumpsticks is .423" & .378" vs .490" & .454". Then when you look at the duration @ .050" you get 236 & 224 for the stockers vs 250 & 232. Hmmm... Can someone straighten me out here. What am I reading wrong? What are your opinions here?

 

advertised duration as far as i know can pretty much be ignored since it does not actually give you any info about when air can flow.
the lift at .050" is the usable part of the lobe.
meaning that you have a lot mroe usable duration with the aftermarket cams than the stock ones.

 

Cool. That makes more sense.

I don't have cam specs for aftermarket cams. Anyone know what these would be comparable too? Maybe like a BC Stage III or a Stage 1/A like Skunk/TODA/JUN etc...?

Thanks.

 

Might be someones opinion of a turbo cam. Sk Stg. 2's,3's PRO 1's,2's,3's, TODA c's, vtec killers, Rocket M22x, 24x, June 3, BC 4&5 all have more duration @.050

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DonF &raquo;</TD></TR><TR><TD CLASS="quote">Might be someones opinion of a turbo cam. Sk Stg. 2's,3's PRO 1's,2's,3's, TODA c's, vtec killers, Rocket M22x, 24x, June 3, BC 4&5 all have more duration @.050 </TD></TR></TABLE>

Thanks DonF. See that's what I was thinking. High lift, low duration turbo cam like a Crower Stage 2T or something of that nature. I just wanted to make sure I was reading the specs correctly. What, in your opinion, would this cam be most comparable too?

 

The intake is almost a Pro1, the EX looks like a Crower Turbo cam or type "R" with more lift.

 

Interesting. Thank you as always DonF for you willingness and expertise.

 

looking at the advertised duration and the .050 number I would say the initial opening and closing ramps are a little harsh.