115+3 versus 114+2 Cam LSA
06-09-2006, 01:42 PM
#21
218/218- 109+0 ??? But 0 overlap is not stock idling ?
As I said I don't put much emphisis on correlating IVC to HP RPM peak, FWIW where you are going with that is getting there and it doesn't peak that early.
The thing you and most of this LS stuff doesn't get is overlaps effect on RPM range, especially on the upper RPM range. Overlap helps cylinder filling in mid to high RPM so it can make the cam hang on longer. If you go from a 114LSA to a 108LSA the motor will pull to the same RPM (in a street application) due to the effect of overlap, it's also going to have more TQ because no matter how you do it that added advance in the higher LSA stuff will ruin all the other valve events just to get the IVC in the right spot.
Bret
06-09-2006, 02:55 PM
#22
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Bret, how tight can you go before you start cutting off RPM?
Take a 220/220 profile on a 116LSA/116ICL which has a 46* IVC @ .050''. We'll say it's a XE-R 220 profile, so that is 143* of duration @ .200'' which makes out a 7.5* IVC.
So then, you take the same 220/220 profile and ignore the 'IDEAL' IVC placement of 42-46* and tighten the LSA, keeping the ICL/ECL inline with the LSA (to make things simple).
HOW TIGHT WITH THE LS DO YOU GO? OR... HOW MUCH OVERLAP IS NEEDED FOR THE SAME PEAK HP #? Actually, with more overlap I bet it would make more peak... So, maybe it would be better to ask...
HOW MUCH OVERLAP WITH THE SECOND CAM IS NEEDED FOR THE SAME AVG HP BETWEEN 5500-6500 RPM AS THE FIRST CAM?
Thanks as always!
Take a 220/220 profile on a 116LSA/116ICL which has a 46* IVC @ .050''. We'll say it's a XE-R 220 profile, so that is 143* of duration @ .200'' which makes out a 7.5* IVC.
So then, you take the same 220/220 profile and ignore the 'IDEAL' IVC placement of 42-46* and tighten the LSA, keeping the ICL/ECL inline with the LSA (to make things simple).
HOW TIGHT WITH THE LS DO YOU GO? OR... HOW MUCH OVERLAP IS NEEDED FOR THE SAME PEAK HP #? Actually, with more overlap I bet it would make more peak... So, maybe it would be better to ask...
HOW MUCH OVERLAP WITH THE SECOND CAM IS NEEDED FOR THE SAME AVG HP BETWEEN 5500-6500 RPM AS THE FIRST CAM?
Thanks as always!
06-09-2006, 04:01 PM
#23
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Originally Posted by SStrokerAce
I don't really care about the idle, it's still going to drive fine in a daily driver.
As I said I don't put much emphisis on correlating IVC to HP RPM peak, FWIW where you are going with that is getting there and it doesn't peak that early.
The thing you and most of this LS stuff doesn't get is overlaps effect on RPM range, especially on the upper RPM range. Overlap helps cylinder filling in mid to high RPM so it can make the cam hang on longer. If you go from a 114LSA to a 108LSA the motor will pull to the same RPM (in a street application) due to the effect of overlap, it's also going to have more TQ because no matter how you do it that added advance in the higher LSA stuff will ruin all the other valve events just to get the IVC in the right spot.
Bret
As I said I don't put much emphisis on correlating IVC to HP RPM peak, FWIW where you are going with that is getting there and it doesn't peak that early.
The thing you and most of this LS stuff doesn't get is overlaps effect on RPM range, especially on the upper RPM range. Overlap helps cylinder filling in mid to high RPM so it can make the cam hang on longer. If you go from a 114LSA to a 108LSA the motor will pull to the same RPM (in a street application) due to the effect of overlap, it's also going to have more TQ because no matter how you do it that added advance in the higher LSA stuff will ruin all the other valve events just to get the IVC in the right spot.
Bret
But you strayed from the original poster's requests.
1- Stock converter
2- Better low- midrange trq
3- 6500 rpm shifts
So this 218/218 109+0 is peaking at 5800 rpms, it pulls nicely for another 500 rpms, perhaps more, but then it will pull on the stock verter at idle requiring a looser stall.
There is where I was lost with your proposal.
It has to work nicely with a stock verter, that is where less overlap is needed or a looser stall.
06-09-2006, 07:22 PM
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This is why this site is so great... On any other board, by now this thread would have reverted back to "You're stupid,", "No, YOU'RE stupid" postings thrown back and forth.... Here, instead, we can discuss (and for me, *learn*) whilst everything is still kept civil. Props to all.
Anyways - YES, indeed - STOCK converter (2100-2200 stall) is staying. Idle quality is very important, as well. SStroker, you mentioned that "you don't really care about the idle..." (3 posts above) - but that's a big part of my cam selection is idle smoothness. Its a DD, mainly by my wife, and there's a lot to say for what she can (or can't) feel when its sitting at a light. The post-cam install PCM tuning will only do so much for smoothing out any idle roughness. The 224/224 .581" 114+2 cam (-4 overlap) in my M6 Firehawk idles too rough for her, and its got a killer tune too.
I realize its extremely difficult to get EVERYTHING one wants out of a cam; thus compromises are always a necessity. In this case, I am willing to lose some upper rpm HP to provide some better low/mid torque. But in the same respects, if I want the truck to shift at 6300-6400rpm, it sure would be nice to continue to produce some good power up to that point. What I *DON'T* need is a cam that holds on 'till 6900+rpm like the 224R cam in my Firehawk. I want that 224R powerband from the Firehawk shifted ~800rpm, such that the HP/Tq I see at 6800rpm on the 224R is essentially the HP/Tq that I see at 6000rpm w/ the chosen cam in the TB-SS.
Keep this going!
Anyways - YES, indeed - STOCK converter (2100-2200 stall) is staying. Idle quality is very important, as well. SStroker, you mentioned that "you don't really care about the idle..." (3 posts above) - but that's a big part of my cam selection is idle smoothness. Its a DD, mainly by my wife, and there's a lot to say for what she can (or can't) feel when its sitting at a light. The post-cam install PCM tuning will only do so much for smoothing out any idle roughness. The 224/224 .581" 114+2 cam (-4 overlap) in my M6 Firehawk idles too rough for her, and its got a killer tune too.
I realize its extremely difficult to get EVERYTHING one wants out of a cam; thus compromises are always a necessity. In this case, I am willing to lose some upper rpm HP to provide some better low/mid torque. But in the same respects, if I want the truck to shift at 6300-6400rpm, it sure would be nice to continue to produce some good power up to that point. What I *DON'T* need is a cam that holds on 'till 6900+rpm like the 224R cam in my Firehawk. I want that 224R powerband from the Firehawk shifted ~800rpm, such that the HP/Tq I see at 6800rpm on the 224R is essentially the HP/Tq that I see at 6000rpm w/ the chosen cam in the TB-SS.
Keep this going!
06-09-2006, 07:40 PM
#25
Originally Posted by Sport Side
Bret, how tight can you go before you start cutting off RPM?
HOW MUCH OVERLAP WITH THE SECOND CAM IS NEEDED FOR THE SAME AVG HP BETWEEN 5500-6500 RPM AS THE FIRST CAM?
HOW MUCH OVERLAP WITH THE SECOND CAM IS NEEDED FOR THE SAME AVG HP BETWEEN 5500-6500 RPM AS THE FIRST CAM?
Originally Posted by PREDATOR-Z
So this 218/218 109+0 is peaking at 5800 rpms, it pulls nicely for another 500 rpms, perhaps more, but then it will pull on the stock verter at idle requiring a looser stall.
There is where I was lost with your proposal.
It has to work nicely with a stock verter, that is where less overlap is needed or a looser stall.
There is where I was lost with your proposal.
It has to work nicely with a stock verter, that is where less overlap is needed or a looser stall.
Why do you think you can base the HP RPM peak solely on one thing in the motor? That's a very narrow minded thinking and your thinking conisides with the idea that the motor does what you want it too... the problem is the motor does what IT wants to reguardless of how you think it works. Engine design, cam design is something where you have to look at things as a whole not as different parts, everything acts on everything else and you have to realize that there are a ton of things that will influence peaks and VE% at each RPM.
Why would it require a looser stall? I know how TQ converters work and they don't see overlap, they see TQ. So why is the change in overlap going to change the need for a different converter?
Originally Posted by 02RedHawk
Anyways - YES, indeed - STOCK converter (2100-2200 stall) is staying. Idle quality is very important, as well. SStroker, you mentioned that "you don't really care about the idle..." (3 posts above) - but that's a big part of my cam selection is idle smoothness. Its a DD, mainly by my wife, and there's a lot to say for what she can (or can't) feel when its sitting at a light. The post-cam install PCM tuning will only do so much for smoothing out any idle roughness.
1. If -4° of overlap is too much for your wife, then DO NOT GET A CAM FOR HER VEHICLE. Worse gas milage, it's a daily driver, your wifes ride... etc, etc, etc would be enough for me to NOT put a cam in it. Just doesn't make sense. Now also realize that I'm looking at this situation as a discussion about cams, not if you should mod your ride or not, so excuse me for that. I would stick better springs on the heads and bump the lift with more rocker arm and call it a day.
2. You can easily smooth out the idle by increasing the RPM, and even with 0° or +4° of overlap at .050" it's going to be a very tame idle at 900rpm. Now bump up the static compression and it will help smooth out the idle even more. The other thing is what matters more the idle quality or the drivability.
3. The stock verter will stall a tad higher with MORE TQ at the flash point, which is basically what is going to happen here.
4. FWIW I've done cams for a guy's wife's car (f-body) that was a lot crazier than this cam being mentioned.
Bret
Last edited by SStrokerAce; 06-09-2006 at 07:48 PM.
06-09-2006, 08:23 PM
#26
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Originally Posted by SStrokerAce
1. If -4° of overlap is too much for your wife, then DO NOT GET A CAM FOR HER VEHICLE. Worse gas milage, it's a daily driver, your wifes ride... etc, etc, etc would be enough for me to NOT put a cam in it.
But I'll tell ya why... Personally, I think the stock '01 LS6 cam in the LS2'ed Trailblazer-SS was (is) a poor choice by the General. It was a cam designed for a car weighing 1200+ lbs less than the Trailblazer, with a different power range and usage that the TB is supposed to have (ie, does anyone tow with a Z06?). Although still very respectable, it doesn't have nearly the amount of torque that I feel the truck needs to have. Somehow, I don't see how the "one cam fits all" concept by GM provides me with the best (optimal) cam for TB-SS's and also for Corvettes. Just my humble opinion, of course... But yes, for the sake of this discussion, I'm focusing on keeping the overlap at a maximum of -10*.
2. You can easily smooth out the idle by increasing the RPM, and even with 0° or +4° of overlap at .050" it's going to be a very tame idle at 900rpm. Now bump up the static compression and it will help smooth out the idle even more. The other thing is what matters more the idle quality or the drivability.
06-10-2006, 09:51 PM
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Originally Posted by Patrick G
The IVC of the stock LS2 cam is much later than 38 degrees ABDC. It's more like 42-43 degrees since the cam is retarded a degree or two. Although your cams have more intake duration, they're going to peak earlier and run out of breath very quickly. You may want to consider running the 114LSA cam with 0 advance. With an IVC of 40 degrees ABDC, you will make more power under the curve and have much more robust power above 5000 rpm (while maintaining solid low-end grunt).
PatrickG - Can you confirm the IVC / VE's of the stock LS2 cam? I ask because I just stumbled across this posting from Ed Curtis...
http://bbs.hardcore50.com/vbulletin/...7&postcount=49
According to his little "chart", the '01 LS6 (same as LS2) cam is 2-degrees advanced, resulting in IVC=36, EVO=43.5.
Thread is here:
http://bbs.hardcore50.com/vbulletin/...&highlight=ls1
06-13-2006, 03:26 PM
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getting a custom cam installed mid july for my TBSS along with catted LT headers, catback. specs are as follows:
214 .559 intake
220 .564 exhaust
111.5 LSA with -6 overlap and a good tune
near stock driveability and idle is a secondary goal. (DD)
ill post the results when finished.
todd
214 .559 intake
220 .564 exhaust
111.5 LSA with -6 overlap and a good tune
near stock driveability and idle is a secondary goal. (DD)
ill post the results when finished.
todd
06-13-2006, 07:27 PM
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Originally Posted by vtodd82
getting a custom cam installed mid july for my TBSS along with catted LT headers, catback. specs are as follows:
214 .559 intake
220 .564 exhaust
111.5 LSA with -6 overlap and a good tune
near stock driveability and idle is a secondary goal. (DD)
ill post the results when finished.
todd
214 .559 intake
220 .564 exhaust
111.5 LSA with -6 overlap and a good tune
near stock driveability and idle is a secondary goal. (DD)
ill post the results when finished.
todd
Any advance ground in? I'm nervous going any bigger than the 212/218 w/ the stock stall, but I do like the #s that your chosen cam is showing on the VE-Calculator. (just wish the overlap was even a bit less for even a better idle)
06-13-2006, 08:02 PM
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Originally Posted by 02RedHawk
Any advance ground in? I'm nervous going any bigger than the 212/218 w/ the stock stall, but I do like the #s that your chosen cam is showing on the VE-Calculator. (just wish the overlap was even a bit less for even a better idle)
i am still kinda up in the air about a catback though. i notice that you are keeping the stock catback. i am getting the catted headers and the quiet version of the SW catback, but i am unsure of how loud it is really gonna be in person. i am also concerned with freeing up some significant power by changing out the HUMUNGO looking stock muffler. i guess i can always change back to stock and sell the SW catback later on though.
good luck in your cam search red.
todd
06-13-2006, 08:11 PM
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Ed Curtis cam?
I need to find some specific info out about our intake, before I finally settle on the cam choice. That may play a big role in how much exhaust-bias I give the cam.
I like to keep things quiet; hence staying with the stock catback....even if it ends up costing me some HP in the end; its worth it to not have the dreaded "drone" that all too often encompasses aftermarket catbacks w/ headers. (not saying that SW's will, though...)
I need to find some specific info out about our intake, before I finally settle on the cam choice. That may play a big role in how much exhaust-bias I give the cam.
I like to keep things quiet; hence staying with the stock catback....even if it ends up costing me some HP in the end; its worth it to not have the dreaded "drone" that all too often encompasses aftermarket catbacks w/ headers. (not saying that SW's will, though...)
Last edited by 02RedHawk; 06-13-2006 at 08:22 PM.
06-13-2006, 08:28 PM
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Originally Posted by 02RedHawk
Ed Curtis cam?
I need to find some specific info out about our intake, before I finally settle on the cam choice. That may play a big role in how much exhaust-bias I give the cam.
I like to keep things quiet; hence staying with the stock catback....even if it ends up costing me some HP in the end; its worth it to not have the dreaded "drone" that all too often encompasses aftermarket catbacks w/ headers. (not saying that SW's will, though...)
I need to find some specific info out about our intake, before I finally settle on the cam choice. That may play a big role in how much exhaust-bias I give the cam.
I like to keep things quiet; hence staying with the stock catback....even if it ends up costing me some HP in the end; its worth it to not have the dreaded "drone" that all too often encompasses aftermarket catbacks w/ headers. (not saying that SW's will, though...)
the intake manifold has given me some grief as well, but iam just gonna go with this and shoot the gun. looks like myself, you and i think evilss are the only ones to break into these things (on the internet scene at least) between the three of use, we should hedge some good knowledge for the rest of the population.
oh, and no the cam isnt one of eds. i certianly trust that he has a GREAT cam made up for these (because i know he does, i have talked with him about it), but i decided to go another route and let ls1speed grind me this one.
todd
06-16-2006, 07:14 PM
#34
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Well I spoke with Thunder Racing today (thanks Paul); Paul pushed either the OMC (214/220 115-2) or more preferred the CheaTR cam (215/230 117+1). Said the CheaTR would outpower the OMC at just about every rpm point, and carry much better in the upper RPM.
He wasn't too fond of the 212/218 combo that I was leaning towards; was really afraid that it would run out of steam before a 6300+ shift point in a 6.0L. Said the 212/218 in the 5.3L's really die by ~5500rpm.
The 214/220 he would expect a shift of 6000-6200, and the CheaTR 215/230 would carry to 6400. Both wouldn't carry as far as when they're installed in a 5.7 / 5.3 motor, simply because the larger 6.0L displacement causes the cam to "act" smaller.
The cam Tony spec'ed for me (214/218 on 112+2 or +4) will significantly run out of steam after about 5k, something that I really don't want of course....although it would have an insane low-end. Think I'll give Tony another call next week and see what else we can come up with. Otherwise, the CheaTR or a slight variant of it may win out as the choice.
He wasn't too fond of the 212/218 combo that I was leaning towards; was really afraid that it would run out of steam before a 6300+ shift point in a 6.0L. Said the 212/218 in the 5.3L's really die by ~5500rpm.
The 214/220 he would expect a shift of 6000-6200, and the CheaTR 215/230 would carry to 6400. Both wouldn't carry as far as when they're installed in a 5.7 / 5.3 motor, simply because the larger 6.0L displacement causes the cam to "act" smaller.
The cam Tony spec'ed for me (214/218 on 112+2 or +4) will significantly run out of steam after about 5k, something that I really don't want of course....although it would have an insane low-end. Think I'll give Tony another call next week and see what else we can come up with. Otherwise, the CheaTR or a slight variant of it may win out as the choice.
Last edited by 02RedHawk; 06-16-2006 at 07:45 PM.
06-17-2006, 09:00 PM
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Originally Posted by Patrick G
The CheaTR would work great in this application if its LSA was narrowed some and it was advanced 2 degrees. Stock, it has an intake valve closing point of 43 degrees ABDC which would make it too much of a top-end cam for this application. Narrowing LSA 2 degrees and adding 2 degrees of advance would make it ideal for a Trailblazer SS.
215/230 .600/.578 115LSA +2.
215/230 .600/.578 115LSA +2.
For this cam (or even the std CheaTR specs), looking at the resulting EVO of 52, how does this cam make good low/mid torque at all?
06-23-2006, 02:57 PM
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Originally Posted by PREDATOR-Z
Correct, "carry well" means it will hold the peak power for a longer time through the rpms before starting to dip downward.
On stock cubes, good lo-midrange trq is relative to the longer stroke BBDC. so 44-45-46 will be really good 47-48-50 good and above 50 will start to suffer in that area.
On stock cubes, good lo-midrange trq is relative to the longer stroke BBDC. so 44-45-46 will be really good 47-48-50 good and above 50 will start to suffer in that area.
Hmm... I've been looking at some of this data for a while now, based upon SStroker's comments and this above...
Have a look at this quickie comparison of the various suggestions:
Cam...........IVO....IVC....EVO....EVC
Stock........-12....36.....43.5....-12.5 (204/211 116 +2 per link above)
VTodd's.......-2......36.....44......-4 (214/220 111.5 + 2.5 (guessed advance))
Tony M.......-3.......37.....43......-5 (214/218 112 +2)
TR OMC......-10.....44......43.....-3 (214/220 115 -2)
CheaTR......-8.5....43.5....53.....-3 (215/230 117 +1)
PatG's.........-8......40......43.....-5 (212/218 114+0)
Trying to compare the OMC and CheaTR, I am struggling to see the similarities between these two (looking at the IVO and EVC's), when trying to also include the EVO (based on Predator's comments). The two TR cams have real late IVOs, about the same IVC's, but the huge difference in EVO is really confusing me... The CheaTR should have no low-end torque at all...(?)
I threw the stock and VTodd's in there just for the helluvit.....
PatrickG / PredatorZ / SStroker / Others, can we carry this conversation a bit further? I'd like to hear more insight on cam selection & thus also learn a boatload more, too....
06-23-2006, 10:51 PM
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you know red, if you can stand to wait 2 more weeks, this cam will be installed and dyno tuned. i have made a few changes - i am keeping that stock catback, but i am going with the catless LT headers instead of the catted version. this should be as loud as i ever want it.
ill post the #'s everywhere once its tuned, and you can decide on a cam for yourself. i am not quite sure what you have targeted for goals, but if its anything like mine (very stock like manners with stock stall and idle with good boost of power) i think this would be good for you.
todd
oh, ill post videos too for exhaust comparables
ill post the #'s everywhere once its tuned, and you can decide on a cam for yourself. i am not quite sure what you have targeted for goals, but if its anything like mine (very stock like manners with stock stall and idle with good boost of power) i think this would be good for you.
todd
oh, ill post videos too for exhaust comparables
06-24-2006, 08:42 AM
#40
Originally Posted by 02RedHawk
Cam...........IVO....IVC....EVO....EVC
Stock........-12....36.....43.5....-12.5 (204/211 116 +2 per link above)
VTodd's.......-2......36.....44......-4 (214/220 111.5 + 2.5 (guessed advance))
Tony M.......-3.......37.....43......-5 (214/218 112 +2)
TR OMC......-10.....44......43.....-3 (214/220 115 -2)
CheaTR......-8.5....43.5....53.....-3 (215/230 117 +1)
PatG's.........-8......40......43.....-5 (212/218 114+0)
Trying to compare the OMC and CheaTR, I am struggling to see the similarities between these two (looking at the IVO and EVC's), when trying to also include the EVO (based on Predator's comments). The two TR cams have real late IVOs, about the same IVC's, but the huge difference in EVO is really confusing me... The CheaTR should have no low-end torque at all...(?)
Stock........-12....36.....43.5....-12.5 (204/211 116 +2 per link above)
VTodd's.......-2......36.....44......-4 (214/220 111.5 + 2.5 (guessed advance))
Tony M.......-3.......37.....43......-5 (214/218 112 +2)
TR OMC......-10.....44......43.....-3 (214/220 115 -2)
CheaTR......-8.5....43.5....53.....-3 (215/230 117 +1)
PatG's.........-8......40......43.....-5 (212/218 114+0)
Trying to compare the OMC and CheaTR, I am struggling to see the similarities between these two (looking at the IVO and EVC's), when trying to also include the EVO (based on Predator's comments). The two TR cams have real late IVOs, about the same IVC's, but the huge difference in EVO is really confusing me... The CheaTR should have no low-end torque at all...(?)
You notice the TR stuff is basically the same except for the early EVO, basically they put all the excess exaust duration on the opening side. That's why you have the wider LSA. Now the other thing that both those cams have is that late IVO, all to cut down overlap and make some power at the higher RPM. I understand thats why they do that, but I don't agree with that professionally. Pile that on with the early EVO and the reason it runs well as a "driver" and makes low end TQ is because it doesn't have any duration and overlap.
I'd try something like a
Cam...........IVO....IVC....EVO....EVC
Stock........-2.......40.....40.......-2
Bret