I don't understand that. I put the clips up there yesterday from here and then checked last night from home. It worked for me then .... Oh - unless you mean Exploder didn't understand the .mov file? You need the Quicktime plugin, but I thought everyone had that.
LOL! Out here is the sticks, I don't know anyone that has an LS1, let alone a cammed one, so I don't know what anything else sounds like. Mine idles at 900 and is lumpy. I haven't tried to see how low I could go on the idle.

 

Isn't that the way of the world??
Facts are not "easily" attained when you play with video games. There's a lot of practical experience, tons of A-B-A testing and many trips to the race track that are the true, real world test beds.
All I can advise you is to stay with one knowledgable person for your entire combination if you want it done right. Nothing screws up a combination more than a dozen "cooks in the kitchen" all pointing fingers at each other when the combo fails. Pick your goals and get a professional who you trust to help you achieve them, not some internet forum user...

But, WTF do I know? After all, it's "your" money you'll be spending, not mine...

Ed

 

232 on a 109 would have better idle/driveability characteristics then a TRex if the valve events just "happen" to be in the right spot

 

Critters valve events are right in line w/ how Shaun does things. Wonder why

I'm having trouble on calculating the VE's given the specs @ .050

The problems are at the intake closing & exhaust opening. Where you take the - of number. Well, if you have a - and the formula already uses a negative, I was always taught, 2 negatives = a positive. Is this the rule?

reference:
Help, I'm thinking this is screwing with my calculations.

 

Here is what my spreadsheet shows...


Quick and Dirty Cam Calculator Spreadsheet
___________________________________________ 0.006 __ 0.050 __ 0.200
Intake Duration - ID_______________________ 281 __ 232 __ 153 3726 Lobe
Exhaust Duration - ED______________________ 281 __ 232 __ 153 3726 Lobe
Lobe Center Angle - LCA (also known as LSA) 109 __ 109 __ 109
Intake Centerline - ICL____________________ 109 __ 109 __ 109


Intake Valve opens - IVO___________________ 31.5 __ 7 __ -32.5 BTDC (- indicates ATDC)
Intake Valve closes - IVC__________________ 69.5 __ 45 __ 5.5 ABDC
Exhaust Valve Opens - EVO__________________ 69.5 __ 45 __ 5.5 BBDC
Exhaust Valve Closes - EVC_________________ 31.5 __ 7 __ -32.5 ATDC (- indicates BTDC)
Exhaust Centerline - ECL___________________ 109 __ 109 __ 109
Overlap____________________________________ 63 __ 14 __ -65 degrees

 

thanks j-rod

i was more curious about when you get a negative for the IVO. then when you go to plug it in for the IVC formula: (-IVO) + intake duration -180.

ex.
IVO= -2* ATDC
IVC=___
Is it:
-(-2) + ID - 180 where the negatives equal a postive. or just
-2 + ID - 180

 

Its
-(-2) + ID - 180

 

Thank you sir.

 

I've been looking at the following just for an example. I don't have any other specs, just sorta goofing around.
@ .050
218/218 109lsa 110icl 108ecl
IO= -1*
IC= 39*
EO= 37*
EC= 1*
Overlap=0

I'm concerned with the I.O.= -1* after top. Would it be wise to fit your intake opening point before top, to help fill the cylinder?

 

This might make it easier for you. Its my VE spreadsheet. I have also expanded it to cover DCR, and header length. I am working on the intake manifold length, etc... right now...


http://users3.ev1.net/~black_ops/cam...calculator.xls

 

Cool, Thanks.

I just looked at the bottom tab VE. Its interesting how Shauns IVC/EVO go about dead opposite with what the rest use.

Could this be explained as. Ok lets see

One of many cams:
IVC 42
EVO 49

Shaun's
IVC 47
EVO 45

Could it be explained as many of the cam manufacturers are stressing there overlap at IO/EC events, where shaun places more of his overlap at these points (ivc, evo)?

 

Jarrod - the exhaust lobe is XE not XE-R. 285/232/148 Doesn't change the 0.050" events, of course.

 

SportSide - try the links for last pass and idle vid please. I'm learning as I go here .....

 

Hmm, I still can't get it to work. I'm sorry. Don't worry about the clips, I don't mean to hassle you.

Would anyone mind explaining indept detail on slower ramps, compared to faster?

Ex., crits [x-er, in./x-e, ex.]

 

Great thread you guys got going. I thought I would add this if it hasn't been already. High performance motorcycle engines are just that-high performance when stock. The cams, heads, exhaust, etc. are already producing over 2 hp per cube. ALL these engines have and have had reverse split cams for over 30 years. Why? I believe that as you approach the 1.3 to 1.5 hp per cube level, intake becomes far more crucial than exhaust. It's too early on Sunday to figure all the math, but lets say that at 7000 rpm the intake only has .010 of a second to injest the air-fuel, and close again. I know it isn't all rpm dependant but I guess the point I am trying to make is this. Obviously, no engine can run w/o drawing in an explosive mixture of some sort. At some point in the equation, it matters not how good your exhaust is, if you cant feed enough fuel/air to the cylinder. I believe the less efficient the exhaust, the more crucial the exhaust duration and lift become. From the factory, the Gen. III has a very good exhaust manifold setup. Add a good LT system, like LG's or Kooks, and exhaust is starting to become less of the problem. These engines rev higher than a lot of built "traditional" small block Chevy's did 30 years ago. At some point in time, the intake valve events are becoming more critical than the exhaust. The great thing about this is we are approaching an unparrallelled performance benchmark. If some one would have told me 10 years ago that a stock Corvette would be pushing the 11 second bracket at the strip and get 30 miles a gallon doing it, I'd think they flipped their flapjack! I believe with this series of engines we have been blessed with, a lot of traditional engineering and previously held beliefs have to be shitcanned. FWIW

 

In my case, it is simply a reverse split cam but using a lazy lobe on the exaust makes it look like a normal split if you look at seat to seat specs. I could have used a smaller XE-R lobe on the exhaust. I wanted the XE-R on the intake to get as much angle inches of area as I could with 232 degrees. I had decided that 230 or 232 was a long as I wanted to go on the intake side for a car that would still see some street duty. The exhaust lobe then followed from that. I'm not clever enough to have any magic reasons

 

I beleive critters cam is a couple degree retarded as well?

Part of my belief on slower ramp rate exhaust lobes is the fact that the cylinder is under pressure at that point. Your not trying to pull in a charge, rather expell something under pressure

 

109 LSA, 110 ICL

 

could you continue on with that thought? or is that all there is to it

Will a slower lobe usually have less duration say @ .200, compared to one of equal values @ .05, just different ramps?

 

Generally yes, but your looking at at it taking into account both sides of the lobe. Preferably Id want an exhaust valve to pick up very quickly in the beginning of the ramp and slowing down after, quickes opening where cylinder pressure is the greatest. on the closing sides, slow to keep valve from bouncing (especially turbo cars where the exhaust valve gets HOT- I think turbo cars should have relatively large exhaust valves to help dissipitate heat, as well as I think it woudl help spool up), although not taking into account of the closing exhaust lobe effect on the charge durign overlap. Can you possibly exhaust the cylinder too quickly and lose the effect of properly timed valve overlap to draw intake charge into the cylinder? I beleive it may be.

You should ask the profesionals though, these are just my opinions based one the goings on in my head