Posted By: Ian
cam lobe separation - 07/30/13 05:23 AM
what are your thoughts on lobe separation with a 408 stroker combo I have been running 107 but was thinking of trying 112 with 13.5 comp indy cnc headed combo
cam lobe separation
Posted By: MR_P_BODY
Re: cam lobe separation - 07/30/13 06:32 AM
JMO... but I have a 112 in my 405ci and I'm not trilled
with it... but part of it is the duration also
with it... but part of it is the duration also
Posted By: 451Mopar
Re: cam lobe separation - 07/30/13 07:06 AM
Lobe seperation is just a way of changing the amount of overlap the cam has without changing the cam lobe duration. With a wider LSA you could goto a cam with more duration and have the same overlap as the smaller cam with a tight LSA. the whole cam profile , duration, LSA, and ICL need to be looked at as a package to identify the opening and closing points of the valves in relation to the piston position, and those numbers will vary depending on application, compression ratios, RPM range, and the intake tract and exhaust tract flow rates (and flow velocity.)
Posted By: Cab_Burge
Re: cam lobe separation - 07/30/13 07:29 AM
If your not going to run a power adder leave the lobe centers at 105 to 107 and put it in at 102 to 104 on the intake lobe 
Posted By: Ian
Re: cam lobe separation - 07/30/13 04:01 PM
thanks guys ,I think I will stick to a 108 l/c I will only spray 100-150 in it 
Posted By: Brian Hafliger
Re: cam lobe separation - 07/31/13 01:06 AM
Quote:
thanks guys ,I think I will stick to a 108 l/c I will only spray 100-150 in it
Using NOS, I would consider a bit wider lca...or run more octane like C16.
Brian
Posted By: Al_Alguire
Re: cam lobe separation - 07/31/13 01:32 AM
Lots of old school thinking here for sure...FWIW mine are 115 and 117 respectively and they seem to make pretty good power. Both NA deals. I think lobe separation is one thing some of the old schoolers just seem to reject. Cannot tell you the last time I was at less that 113. From what we have seen it seems to be way less peaky power bands going with and increased lobe separation. But you can always just run an old purple shaft and wonder why some are faster....
Posted By: B3422W5
Re: cam lobe separation - 07/31/13 02:09 AM
Quote:
Lots of old school thinking here for sure...FWIW mine are 115 and 117 respectively and they seem to make pretty good power. Both NA deals. I think lobe separation is one thing some of the old schoolers just seem to reject. Cannot tell you the last time I was at less that 113. From what we have seen it seems to be way less peaky power bands going with and increased lobe separation. But you can always just run an old purple shaft and wonder why some are faster....
Good points, but you run a lot of compression don't you? Which N/A removes some of the wide LSA negatives.
True story, I had at one time W5 topend sitting on my 416 shortblock I had previously had eddie heads on that I sold. When I switched to the better heads I left the cam alone. It remained 260/266 598/623 flat tappet I had under the eddies(likely not optimal)
A certain cam guru/ seller who used to post on here and I got to know told me I was sure to see improvement by going to a 112 ( about all it seems he recommended for every N/A combo).
Knowing my combo well, he ground a cam on a 112 to his specs for my combo. 258/268 same ish lift numbers.
Anyhow, heavy car(3350) 11.8 compression. Car never again with the new cam got even within a tenth of the generic 107 LSA cam it replaced.
Car was a dog 60 foot, felt just dead. I will say the MPH changed very little.
Cam just gave up too much in the first part of the track to overcome.
Anything I have see n/a in the small block world that isn't exotic, say Indy heads and lower on the food chain runs better on tighter stuff.
Be curious what LSA stock and super stock small block stuff runs.....
But yeah... 15+ to 1 big headed n/a stuff might be more forgiving
Posted By: dodgeboy11
Re: cam lobe separation - 07/31/13 02:34 AM
Depends on your application and how good the heads are. I know the little 360 I built for my truck had 114 lsa and while it didn't have a lot of peak power, it pulled from 900 rpm all the way to 6000 and had a flat even powerband the whole way. Now I'm not saying the heads were good, because they weren't, but for the application, it worked. Wider lobe separation with good heads will carry the rpm further but may not get there as fast depending on the rest of the combination. Large cubic inch engines tend to like more separation than smaller ones. For a road race car I think I would tend towards the wider end of the spectrum. If I remember correctly on the twin cam mercedes stuff I messed with, the exhaust camshaft had the variable gear on it. At lower rpm it would move to increase the separation for a smoother, cleaner idle, but in the midrange it would tighten up, then once it got past the higher end, it would widen up again to carry the rpm higher. One advantage to multiple cams or cams inside of cams like the new viper v10. I plan on running in the 111-112 range with my W9 headed 408 for my challenger, but it's primary purpose will be road courses so the rpm variance will be much wider. If I was setting it up for drag racing, I'd throw in 106-108 to pick up the peak power and match everything else to that power range. If you like a powerband that's flat, go wide, if you like steep climbing power that drops off quicker, go tighter. Keep in mind this is general rule of thumb, the entire package determines what cam timing events are needed and only lots of testing will get it where it needs to be.
Posted By: Ian
Re: cam lobe separation - 07/31/13 04:26 AM
thanks guys nice info , I have been running 107 l/c 255/262 670/650 with 230 indys with 11.4 comp the car runs 10.90@123 mph and good 200 hit 9.57@142 with 1 3/4 pipes full system 105 octane stock block at 3500 lbs 780 moroso hp ,doing a new short with 13.1 cam will be 272/276 700 lift I think I will go 108 ,the gas will be less this time
Posted By: goldmember
Re: cam lobe separation - 07/31/13 06:35 AM
LSA is useless without the total combo. What works in one will be a turd in another.
Posted By: LA360
Re: cam lobe separation - 07/31/13 01:54 PM
What kind of RPM are you expecting to run?
Posted By: BradH
Re: cam lobe separation - 07/31/13 02:58 PM
Quote:
LSA is useless without the total combo. What works in one will be a turd in another.
Although stated a little differently than I would have, IMO that's still the gist of it.
I wish I had more first-hand experience w/ the results of different LSA combinations and was less reliant on others' results. I've certainly come to the conclusion that certain combinations & characteristics definitely favor wider LSAs. However, I don't believe the types of engnines I run (modified NA stock-stroke 440 street/strip combinations) fall into that category.
Posted By: Ian
Re: cam lobe separation - 07/31/13 03:13 PM
Quote:7500 rpm
What kind of RPM are you expecting to run?
Posted By: Cab_Burge
Re: cam lobe separation - 07/31/13 05:38 PM
My experiences with N/A SB with stock type heads and with BB with the same conditions is that they both liked closer LSA, IE 106 to 100. My expereinces(dyno testing and at the track) is the closer the lobe centers and having the intake lobe centers advanced built more power under 6000 RPM. Once the the motor are modifed for higher RPM use then the wider LSA help move the power range higher up in the RPM range, above 5000 RPM. Of course when doing that you need a looser converter, diffferent gear ratios, trans and rear end, better cam, more lift and duration, and associated valve gear, bigger intake sustem and fuel supply and so on 
Ultimately speed costs money, how much do you want to spend and how fast do you want to go, HUH Al 
Ultimately speed costs money, how much do you want to spend and how fast do you want to go, HUH Al
Posted By: mopar dave
Re: cam lobe separation - 07/31/13 05:45 PM
Ian, my new grind pulls like a freight train with 106 LSA and 101 install. just got to get it to hook. I think most nitrous cams are on a 112 thou. if you don't spray it all the time i'd go tighter.
Posted By: D-50
Re: cam lobe separation - 07/31/13 11:53 PM
I just looked at my cam card and it says the lobe separation is 104 int./ 112 ex. How well with that work with NOS ? I would like to spray mine and make a 5.99 or better 1/8 mile pass.
Posted By: B3422W5
Re: cam lobe separation - 08/01/13 12:19 AM
I noticed a wideLSA cam likes lots of compression, convertor, and RPM, and real good heads. All things a typical 59 degree Mopar small block doesn't need or have N/A.
That said, shift recovery seems improved over a narrower cam.can't see any Benefit to a 112-114 stick with Indy, W5, W2, Eddie, ect stroker builds
Pro stock.... Sure
That said, shift recovery seems improved over a narrower cam.can't see any Benefit to a 112-114 stick with Indy, W5, W2, Eddie, ect stroker builds
Pro stock.... Sure
Posted By: D-50
Re: cam lobe separation - 08/01/13 12:40 AM
Quote:
I noticed a wideLSA cam likes lots of compression, convertor, and RPM, and real good heads. All things a typical 59 degree Mopar small block doesn't need or have N/A.
That said, shift recovery seems improved over a narrower cam.can't see any Benefit to a 112-114 stick with Indy, W5, W2, Eddie, ect stroker builds
Pro stock.... Sure
I have the Indy 360-2 heads,10.9 comp. 255/266@ .050,5500 PTC convertor and shift at 6800. It made peak hp at 7300 on the dyno. I am thinking about spraying 100/125 shot of NOS.
Posted By: Al_Alguire
Re: cam lobe separation - 08/01/13 12:57 AM
Funny you say that. My experience with wide LSA cams came from my time playing with Pontiacs, hardly good cylinder head high RPM cars. This was a number of years ago but most of their cams have or had back then wide LSA's. This is what got me to thinking of trying them in a Mopar and we have been very happy with the results.
Narrow lobe center stuff sems to be way peaky to me, or at least what I have had experience with. OH yeah I think most SS stuff is going to have a wide lobe center too.
I have seen the wider LSA's have made more power and gone quicker at the track. SB Fords, Pontiacs Chevys and Mopars. They seem to spread out torque as well so from my experience I will stick with what I have seen work for me. Of course a cam is only ONE part of the equation, to make a car run good numbers it is a combination not a magic part that makes the difference.
I think it is interesting to see what kind of results people get with certain combinations. Also would be interested to see how far they went to see IF there was a gain. Or if it was simply a cam swap and nothing else.
Narrow lobe center stuff sems to be way peaky to me, or at least what I have had experience with. OH yeah I think most SS stuff is going to have a wide lobe center too.
I have seen the wider LSA's have made more power and gone quicker at the track. SB Fords, Pontiacs Chevys and Mopars. They seem to spread out torque as well so from my experience I will stick with what I have seen work for me. Of course a cam is only ONE part of the equation, to make a car run good numbers it is a combination not a magic part that makes the difference.
I think it is interesting to see what kind of results people get with certain combinations. Also would be interested to see how far they went to see IF there was a gain. Or if it was simply a cam swap and nothing else.
Posted By: B3422W5
Re: cam lobe separation - 08/01/13 01:14 AM
Quote:
I just looked at my cam card and it says the lobe separation is 104 int./ 112 ex. How well with that work with NOS ? I would like to spray mine and make a 5.99 or better 1/8 mile pass.
A cam only has one LSA, that is ground when it's made. The LSA is degrees between intake and exhaust centerlines in crank degrees.
Wider kills low end torque and bleeds off effective compression, but makes more high rpm horsepower
Posted By: Sport440
Re: cam lobe separation - 08/01/13 01:44 AM
Quote:Quote:
I just looked at my cam card and it says the lobe separation is 104 int./ 112 ex. How well with that work with NOS ? I would like to spray mine and make a 5.99 or better 1/8 mile pass.
A cam only has one LSA, that is ground when it's made. The LSA is degrees between intake and exhaust centerlines in crank degrees.
Wider kills low end torque and bleeds off effective compression, but makes more high rpm horsepower
LSA is in Cam degrees ILC is in Crank degrees. The numbers D50 posted are ILC in crank degrees. His cam has a 108 LSA and is installed 4* advanced giving him those numbers of ILC
Posted By: B3422W5
Re: cam lobe separation - 08/01/13 02:58 AM
Quote:Quote:Quote:
I just looked at my cam card and it says the lobe separation is 104 int./ 112 ex. How well with that work with NOS ? I would like to spray mine and make a 5.99 or better 1/8 mile pass.
A cam only has one LSA, that is ground when it's made. The LSA is degrees between intake and exhaust centerlines in crank degrees.
Wider kills low end torque and bleeds off effective compression, but makes more high rpm horsepower [
LSA is in Cam degrees ILC is in Crank degrees. The numbers D50 posted are ILC in crank degrees. His cam has a 108 LSA and is installed 4* advanced giving him those numbers of ILC
Sorry, I thought he said 104 and 112 a few posts up, which didn't/ doesnt make sense to me when we were talking LSA, which is only 1 number, not two.... Might want to read that post he made I was referencing
Posted By: B3422W5
Re: cam lobe separation - 08/01/13 03:24 AM
Quote:
Funny you say that. My experience with wide LSA cams came from my time playing with Pontiacs, hardly good cylinder head high RPM cars. This was a number of years ago but most of their cams have or had back then wide LSA's. This is what got me to thinking of trying them in a Mopar and we have been very happy with the results.
Narrow lobe center stuff sems to be way peaky to me, or at least what I have had experience with. OH yeah I think most SS stuff is going to have a wide lobe center too.
I have seen the wider LSA's have made more power and gone quicker at the track. SB Fords, Pontiacs Chevys and Mopars. They seem to spread out torque as well so from my experience I will stick with what I have seen work for me. Of course a cam is only ONE part of the equation, to make a car run good numbers it is a combination not a magic part that makes the difference.
I think it is interesting to see what kind of results people get with certain combinations. Also would be interested to see how far they went to see IF there was a gain. Or if it was simply a cam swap and nothing else.
In my case, after Scott brown specced the cam I flogged the car weekly the whole summer trying everything I could think of just to get the car to run like it had with the old cam that itself I didnt consider optimal after leaving it in after a top end swap as I detailed earlier
Initial outing with the new top end and old cam netted a 10.38, in more typical air it ran mid 10.40's
About 6 weeks Into racing season, I made the swap to the112 Scott ground up.
Car ran 60's and low 70's no matter timing, jetting, changing launch technique or shift points.
Finally it got to be late August and I decided to wait till end of season to put either another cam or my old one back in...... That night it ran its best ever lap with that 112, 10.55...... The next pass that night it blew up( broke cast stroker I was stupidly leaning on. That night would have been a 10.40-42 pass with the old cam
Car just was a dog out of the gate with that wide cam, could actually feel it in the seat, didn't need the 60/330 numbers to prove it
Posted By: Mopar-Al
Re: cam lobe separation - 08/01/13 04:33 AM
I run a 113 lobe seperation installed at 113 center. I launch around 6k or a bit more and shift at 8400, I am running B1 originals on a 511. I have around 13.8 comp. The car just flatazz pulls on the top end and is deadly consistant. My combo seems to work as expected for me.
Posted By: moparmanjames
Re: cam lobe separation - 08/01/13 04:49 AM
Quote:
Narrow lobe center stuff sems to be way peaky to me, or at least what I have had experience with. OH yeah I think most SS stuff is going to have a wide lobe center too.
I have seen the wider LSA's have made more power and gone quicker at the track.
You are correct, a narrow lobe separation angle will make more peak torque in a narrower power range. A wide lobe separation angle flattens and broadens the curve.
Think of a narrow LSA representing a narrow peak and a wide LSA representing a longer mesa type peak.
The narrow LSA will give you a much higher number at a lower rpm, but the wide LSA will give you a higher number in the higher rpms and is easier to hook up because of less peak torque.
General Motors used this wide LSA/higher compression formula when building their corvette to get good mileage without sacrificing much performance.
Posted By: B3422W5
Re: cam lobe separation - 08/01/13 04:50 AM
Quote:
I run a 113 lobe seperation installed at 113 center. I launch around 6k or a bit more and shift at 8400, I am running B1 originals on a 511. I have around 13.8 comp. The car just flatazz pulls on the top end and is deadly consistant. My combo seems to work as expected for me.
Yep, perfect application for a wide LSA cam, lots of compression and RPM, good heads, and no need for low RPM torque as evidenced by your launch rpm. Exactly the ingredients one would need to make a wide LSA work/ shine N/A.
Kinda helps make the point.
Posted By: Sport440
Re: cam lobe separation - 08/01/13 05:25 AM
Quote:Quote:Quote:Quote:
I just looked at my cam card and it says the lobe separation is 104 int./ 112 ex. How well with that work with NOS ? I would like to spray mine and make a 5.99 or better 1/8 mile pass.
A cam only has one LSA, that is ground when it's made. The LSA is degrees between intake and exhaust centerlines in crank degrees.
Wider kills low end torque and bleeds off effective compression, but makes more high rpm horsepower [
LSA is in Cam degrees ILC is in Crank degrees. The numbers D50 posted are ILC in crank degrees. His cam has a 108 LSA and is installed 4* advanced giving him those numbers of ILC
Sorry, I thought he said 104 and 112 a few posts up, which didn't/ doesnt make sense to me when we were talking LSA, which is only 1 number, not two.... Might want to read that post he made I was referencing
Don, I read it just fine. I was correcting both you and him. One and Two
He did state two numbers as you stated incorrectly as LSA numbers 104 and 112.
"Correction" They are actually Lobe centerline numbers measured in Crank degrees.
You stated that LSA numbers were measured in Crank degrees.
"Correction" LSA numbers are measured in Cam degrees.
I just dont want to confuse people, I know you know your stuff, even I miss typed stuff myself.
Posted By: B3422W5
Re: cam lobe separation - 08/01/13 06:26 AM
LSA ( lobe separation angle) is in fact measured in crank degrees,I have said twice now it is a fact it is measured in crankshaft degrees between the e
xhaust and intake centerlines...... That spread in CRANKSHAFT degrees is the LSA, can't explain it any clearer
xhaust and intake centerlines...... That spread in CRANKSHAFT degrees is the LSA, can't explain it any clearer
Posted By: Cab_Burge
Re: cam lobe separation - 08/01/13 06:35 AM
I've always wondered how you would measure camshaft degrees All the specs.I have seen on a cam card are in reference to crankshaft degrees, I think
All the specs.I have seen on a cam card are in reference to crankshaft degrees, I think
Posted By: an8sec70cuda
Re: cam lobe separation - 08/01/13 01:37 PM
Quote:Quote:
I run a 113 lobe seperation installed at 113 center. I launch around 6k or a bit more and shift at 8400, I am running B1 originals on a 511. I have around 13.8 comp. The car just flatazz pulls on the top end and is deadly consistant. My combo seems to work as expected for me.
Yep, perfect application for a wide LSA cam, lots of compression and RPM, good heads, and no need for low RPM torque as evidenced by your launch rpm. Exactly the ingredients one would need to make a wide LSA work/ shine N/A.
Kinda helps make the point.
with B3422W5...been there, done that, wasted money.
Posted By: Sport440
Re: cam lobe separation - 08/01/13 02:15 PM
When a Cam comp. states a cams Lobe Seperation Angle as in 108 , 110 , or 112, they are indeed referencing a Lobe seperation in CAM degrees
IN D50,s case he states Two numbers add those up! They will equal 216 CRANK degrees. So is his cam a 216 LSA, because in Crank degrees those lobes are indeed 216* apart
Or 108* apart in Cam degrees. The crank turns twice for every one revolution of the cam.
Lobe seperation angle is Cam degrees.
Installed Intake centerline is Crank degrees.
The Math doesnt lie, it either is or isnt.
IN D50,s case he states Two numbers add those up! They will equal 216 CRANK degrees. So is his cam a 216 LSA, because in Crank degrees those lobes are indeed 216* apart
Or 108* apart in Cam degrees. The crank turns twice for every one revolution of the cam.
Lobe seperation angle is Cam degrees.
Installed Intake centerline is Crank degrees.
The Math doesnt lie, it either is or isnt.
Posted By: MR_P_BODY
Re: cam lobe separation - 08/01/13 02:30 PM
Posted By: MR_P_BODY
Re: cam lobe separation - 08/01/13 02:46 PM
Quote:
When a Cam comp. states a cams Lobe Seperation Angle as in 108 , 110 , or 112, they are indeed referencing a Lobe seperation in CAM degrees
IN D50,s case he states Two numbers add those up! They will equal 216 CRANK degrees. So is his cam a 216 LSA, because in Crank degrees those lobes are indeed 216* apart
Or 108* apart in Cam degrees. The crank turns twice for every one revolution of the cam.
Lobe seperation angle is Cam degrees.
Installed Intake centerline is Crank degrees.
The Math doesnt lie, it either is or isnt.
Look at the graph I just posted... does it look like
the lobes are greater than 180* apart
EDIT
The cam LSA is indeed measured on the cam itself
but in the above you add the 2 together then divide
by 2 to find the average(108 in this case)
Posted By: Sport440
Re: cam lobe separation - 08/01/13 08:08 PM
Quote:Quote:
When a Cam comp. states a cams Lobe Seperation Angle as in 108 , 110 , or 112, they are indeed referencing a Lobe seperation in CAM degrees
IN D50,s case he states Two numbers add those up! They will equal 216 CRANK degrees. So is his cam a 216 LSA, because in Crank degrees those lobes are indeed 216* apart
Or 108* apart in Cam degrees. The crank turns twice for every one revolution of the cam.
Lobe seperation angle is Cam degrees.
Installed Intake centerline is Crank degrees.
The Math doesnt lie, it either is or isnt.
Look at the graph I just posted... does it look like
the lobes are greater than 180* apart
EDIT
The cam LSA is indeed measured on the cam itself
but in the above you add the 2 together then divide
by 2 to find the average(108 in this case)
Yep, Indeed
Everyone who listed thier LSA whether it was 107 to 117 was in Cam degreees.You could list it in Crank degrees too, but nobody did. If they did the numbers would be 214 to 234
Posted By: B3422W5
Re: cam lobe separation - 08/01/13 08:23 PM
Sport 440.....said
"Lobe seperation angle is cam degrees"
From Car Tech, by Mike Petralia
"Lobe Separation Angle (LSA) is NOT the same as Lobe Centerlines (LC), although the two are directly connected.
The Lobe Separation Angle is measured as the degrees that the CRANKSHAFT rotates BETWEEN the exhaust valve’s maximum lift point (aka: Exhaust Centerline) and the intake valve’s maximum lift point (aka: Intake Centerline). Check the lead illustration in this story from COMP Cams to show this effect. The highest lift points on the lobes are referred to as the cam “Lobe Centerlines” and are usually ground somewhere between 102 and 122 CRANKSHAFT degrees. Since Lobe Centerline is referenced in relation to crankshaft degrees as well, it can be moved around, depending on where you install the cam."
Hope this puts this to bed 
"Lobe seperation angle is cam degrees"
From Car Tech, by Mike Petralia
"Lobe Separation Angle (LSA) is NOT the same as Lobe Centerlines (LC), although the two are directly connected.
The Lobe Separation Angle is measured as the degrees that the CRANKSHAFT rotates BETWEEN the exhaust valve’s maximum lift point (aka: Exhaust Centerline) and the intake valve’s maximum lift point (aka: Intake Centerline). Check the lead illustration in this story from COMP Cams to show this effect. The highest lift points on the lobes are referred to as the cam “Lobe Centerlines” and are usually ground somewhere between 102 and 122 CRANKSHAFT degrees. Since Lobe Centerline is referenced in relation to crankshaft degrees as well, it can be moved around, depending on where you install the cam."
Hope this puts this to bed
Posted By: Sport440
Re: cam lobe separation - 08/01/13 09:35 PM
Don, Im glad your smiling this time. Last time you were yelling at me, I heard you.
Sport 440 Said
" Lobe Seperation Angle is in Cam Degrees"
Yep, I said that alright.
And this wont be put to bed until I hear you Agree
In thats Mike P,s text it has an Error. He used the word Crank when it should of been Cam in reguards to LSA.
LSA Can be measured in Cam or Crank degrees
But the Numbers that everybody states including you, me, the others, and All the Cam companies for LSA are in Cam degrees.
If you see a 110 LSA Comp cam advertised, that number is in Cam degrees. If its advertised in Crank degrees as Mike P states, it would be a 220 LSA cam. They would have the Same exact LSA, just measured two different ways.
That text your reading from Mike Petralia is wrong in that one word error crank vs cam.
Now Lobe Centers are indeed measured in Crank degrees. A 110 LSA cam installed straight up or Dead center between its two peak lobe lifts will be at 55* at the cam rotate it 55* ATDC and the crank moves 110*
Rotate it BTDC 55* and the crank moves 110*
Both intake and exhaust Lobe centers are at 110* dead center or straight up as I call it.
The total distance between the two 220 Crank degrees or 110 Cam degrees,.
Tell me How can Mikes Petralia text still be right. Not a phone text ,just the text your reading.
Hang with me on this LSA, LC, can be confusing at times, and for alot of people, even me at one time.
But, I got a handle on this, there is no doubt, not a shadow, from what Im telling you.
Dont listen to Mike Petralias single word Misprint. Its misleading you.
Listen to Sport 440, or Mike F/ me Further read the above and think about it and Listen to your own mind.
We will be on the Same page, I guarantee it.
Sport 440 Said
" Lobe Seperation Angle is in Cam Degrees"
Yep, I said that alright.
And this wont be put to bed until I hear you Agree
In thats Mike P,s text it has an Error. He used the word Crank when it should of been Cam in reguards to LSA.
LSA Can be measured in Cam or Crank degrees
But the Numbers that everybody states including you, me, the others, and All the Cam companies for LSA are in Cam degrees.
If you see a 110 LSA Comp cam advertised, that number is in Cam degrees. If its advertised in Crank degrees as Mike P states, it would be a 220 LSA cam. They would have the Same exact LSA, just measured two different ways.
That text your reading from Mike Petralia is wrong in that one word error crank vs cam.
Now Lobe Centers are indeed measured in Crank degrees. A 110 LSA cam installed straight up or Dead center between its two peak lobe lifts will be at 55* at the cam rotate it 55* ATDC and the crank moves 110*
Rotate it BTDC 55* and the crank moves 110*
Both intake and exhaust Lobe centers are at 110* dead center or straight up as I call it.
The total distance between the two 220 Crank degrees or 110 Cam degrees,.
Tell me How can Mikes Petralia text still be right. Not a phone text ,just the text your reading.
Hang with me on this LSA, LC, can be confusing at times, and for alot of people, even me at one time.
But, I got a handle on this, there is no doubt, not a shadow, from what Im telling you.
Dont listen to Mike Petralias single word Misprint. Its misleading you.
Listen to Sport 440, or Mike F/ me
Further read the above and think about it and Listen to your own mind.We will be on the Same page, I guarantee it.
Posted By: B3422W5
Re: cam lobe separation - 08/01/13 10:31 PM
Actually, when we were argueing last night, i was at home and using my phone for internet......i did a search and found that article i quoted right at the top of the search... after reading it and seeing it for what it was( incorrect) i figured i would try you on and post it.....
It didnt work...lol
It didnt work...lol
Posted By: Sport440
Re: cam lobe separation - 08/01/13 11:57 PM
As far as lobe seps go, my testing was similer to yours in NA motors 500/600 hp or so. I went from a 108 LSA to a 112 LSA The car slowed down a tenth or two. The 112 Was much more street friendly though, but it just didnt have the midrange that it did before.
For the OP I would not go with the 112, 110 maybe because he is using some nitrous on occasion.
Me ,Id probably stick with the 108 LSA.
For the OP I would not go with the 112, 110 maybe because he is using some nitrous on occasion.
Me ,Id probably stick with the 108 LSA.
Posted By: 451Mopar
Re: cam lobe separation - 08/02/13 04:57 AM
I think some of the confusion between the LSA and ICL numbers is in the way they are related to each other. The Lobe Seperation Angle is the number of camshaft degrees between the center of the Exhaust lobe and the center of the Intake lobe. Because the cam turns at 1/2 the speed of the crank, If you wanted to express the advertised LSA numbers in crank degrees you multiply the LSA by 2.
The relationship between the LSA and Intake Center Line (ICL) is when you install a cam "straight up", the piston will be at TDC right in the center between of the exhaust and intake lobes where they overlap. If you go from TDC clockwise to the number of degrees the LCA number is in crank degreed, then the cam should be at max lift (center line of the intake lobe) which verifies that at TDC the cam was 1/2 between the center of the Exhaust and Intake lobes. So when degree the cam "straight up" with the ICL you are just verifying the exhaust and intake valve are equally open (overlap) at TDC.
The reason cams are degree in near peak lift (usually 0.050 below peak lift) is the lobes are more symmetrical around the lobe center line, than at low lifts where the opening and closing ramps cam make the lobes asmmetrical (more or less lift on one lobe side compared to the other side of the lobe at equal distance from the lobe centerline.)
The relationship between the LSA and Intake Center Line (ICL) is when you install a cam "straight up", the piston will be at TDC right in the center between of the exhaust and intake lobes where they overlap. If you go from TDC clockwise to the number of degrees the LCA number is in crank degreed, then the cam should be at max lift (center line of the intake lobe) which verifies that at TDC the cam was 1/2 between the center of the Exhaust and Intake lobes. So when degree the cam "straight up" with the ICL you are just verifying the exhaust and intake valve are equally open (overlap) at TDC.
The reason cams are degree in near peak lift (usually 0.050 below peak lift) is the lobes are more symmetrical around the lobe center line, than at low lifts where the opening and closing ramps cam make the lobes asmmetrical (more or less lift on one lobe side compared to the other side of the lobe at equal distance from the lobe centerline.)
Posted By: LA360
Re: cam lobe separation - 08/02/13 08:06 AM
I would be looking at something with a 110-112 lobe separation angle if it was my engine and I was using Nitrous all the time.
Posted By: emarine01
Re: cam lobe separation - 08/02/13 02:59 PM
Ian, The way I look @ it is where do you want the power, I run old 59* factory blocks with W5 heads so @ 414 inches we run outa breath over 7k & the block and valve train don't seem real happy higher , WE can pull to 7500 with a small roller 260@ .050 .685 lift 106 0n 106 but the real hard pull is down around 6 to 6800, In the mud the resistance will pull the engine down fast so a higher TQ, shorter power band seems to work better for us, We ran larger rollers with wider spreads 109 , 112, and had problems turing larger more aggressive tires requiring more gear & converter thus reducing wheel speed and having to turn more rpm to compensate, The shift recovery is also faster with the shorter power band. The Nos guys in the mud seem to favor 107-108 advanced 4 with a boatload more exhaust duration @ least 10*+, To have a setup that runs Na and Nos and not favor one side is hard to do, seems ya gotta trade a little somewhere.
Posted By: Ian
Re: cam lobe separation - 08/02/13 03:22 PM
thanks guys ,there is a lot of good facts and engine combos vs real changes with lobe separation , I think I will be running a lot more aspirated next year so 108 it will be ,thanks
Posted By: Brian Hafliger
Re: cam lobe separation - 08/02/13 04:31 PM
Quote:
thanks guys ,there is a lot of good facts and engine combos vs real changes with lobe separation , I think I will be running a lot more aspirated next year so 108 it will be ,thanks
It only takes one time on NOS to hurt the engine....the engine doesn't care how many times a year you run NOS...if it's not built for the x amount of times you squeeze it will let you know it's not happy
Posted By: Ian
Re: cam lobe separation - 08/02/13 05:08 PM
thanks brian ,I know a little about nos only been running it for 25 years
Posted By: wireweld
Re: cam lobe separation - 08/04/13 03:14 PM
What about efi. Does a wider lsa work better? Like a 112 or 114?