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sounds great! what else is done to the truck?  How does it run, any drivability issues?  alot of prople said to go with the 224 on a 114, yours is a 112, where does the power come on at?  new springs, lifters, rockers??    thanks

 

Well, quite a list actually... '05 fans, Nelson harness, 160* stat, '05 K&N intake, Thorley headers, Magnaflow cats, Flo-Pro HD muffler. As far as the cam, I did change to Comp 918's. Stock rockers. Tranny mods probably next week.

 

Driveability is fine, except for the idle. It is too low, & stalls without notice when idling in gear. :banghead: That will get fixed tomorrow. After the retune I will post my opions on true drivability. Oh, stock converter too (and it isn't bad).

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whats the advantage or disadvantage of a 112 to a 114.  Which one does what???  I know what LSA is, just not what it does.

 

 

Brad

From what ive been reading the LSA is lobe seperation angle, the differenc between the 112/114 i understand is idle quality and pwr thru the rpm range. the 112 will have more lope and more pwr in the mid range, where the 114 will idle a little smoother and have a little broader pwr range. I hope this is correct, anyone else want to add. Im not knowledgable enough to explain the whole lsa thing with valve timing so someone else has to add on that. :dunno: Hope this helps!

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:withstupid: There is a lot more to camming than duration and LSA numbers, acutally the secret is where the valve events are phased in relation to crank stroke length, static compression ratio, and fuel octane. VERY basic overview -

 

Lobe Separation Angle is the inverse of overlap; overlap is the amount of time the intake and exhaust valves are both open at the same time. Within reason - the wider (bigger) the LSA the FLATTER/BROADER the torque curve, conversely the narrower (smaller) the LSA the PEAKIER the torque curve and more 'explosive' the engine will be in the midrange; it will also display a very distinct 'sweet spot' in the RPM band.

 

I rememebr when the hot ticket was huge duration 108-degree LSA cam in a BBC; the power would not come on until after 2500-rpm but the tach needle would just literally jump to about 5500 or 6-grand, and then the ride was pretty much over and time to grab the next gear, but the engine pulled ungodly hard in the midrange. You could even order 104-degree cams, I've seen them marketed for marine use where engines typically are running at a preset RPM.

 

Contemporary trends in camming are more towards the 112-114 degree LSA, so the power comes on sooner (say, 1500-rpm) and the engine pulls a lot higher, like 7000-7500 RPM but will not be so peaky in it's torque curve; however the engine is turning so many R's by that point you're making a hell of a lot of power, plus recovery is better going to the next gear.

 

Low LSA cams will work against forced induction, the increased overlap bleeds off cylinder pressure below the cam's 'torque range'; you may as well not even have forced induction. But on a N/A street application it can be a really fun combo, and more efficient when operated in it's 'sweet spot'. Higher LSA cams are usually called for in FI applications to preserve cylinder pressure.

 

Mr. P. :)

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:withstupid:  There is a lot more to camming than duration and LSA numbers, acutally the secret is where the valve events are phased in relation to crank stroke length, static compression ratio, and fuel octane.  VERY basic overview -

 

Lobe Separation Angle is the inverse of overlap; overlap is the amount of time the intake and exhaust valves are both open at the same time.  Within reason - the wider (bigger) the LSA the FLATTER/BROADER the torque curve, conversely the narrower (smaller) the LSA the PEAKIER the torque curve and more 'explosive' the engine will be in the midrange; it will also display a very distinct 'sweet spot' in the RPM band.

 

I rememebr when the hot ticket was huge duration 108-degree LSA cam in a BBC; the power would not come on until after 2500-rpm but the tach needle would just literally jump to about 5500 or 6-grand, and then the ride was pretty much over and time to grab the next gear, but the engine pulled ungodly hard in the midrange.  You could even order 104-degree cams, I've seen them marketed for marine use where engines typically are running at a preset RPM.

 

Contemporary trends in camming are more towards the 112-114 degree LSA, so the power comes on sooner (say, 1500-rpm) and the engine pulls a lot higher, like 7000-7500 RPM but will not be so peaky in it's torque curve; however the engine is turning so many R's by that point you're making a hell of a lot of power, plus recovery is better going to the next gear.

 

Low LSA cams will work against forced induction, the increased overlap bleeds off cylinder pressure below the cam's 'torque range'; you may as well not even have forced induction.  But on a N/A street application it can be a really fun combo, and more efficient when operated in it's 'sweet spot'.  Higher LSA cams are usually called for in FI applications to preserve cylinder pressure.

 

Mr. P. :)

 

 

wow, thanks for the info!!! So on a heavy N/A truck with stock converter, a larger LSA would be best for us guys(street and track)? do they make a 116? When does the LSA get to big? For a low LSA you have to have a higher stall to really use the cam then right? The duration also gets lower with a low LSA then right? On a low LSA you could have the cam profile real steep to avoid over lap on a S/C motor and still keep cylinder pressure up, right? What cam do you feel works well in our N/A stock converter trucks, and why?

 

Thanks again

Brad

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