Cam Qs...
05-15-2009, 05:28 PM
#1
Cam Qs...
I searched, and didn't find anything. I was hoping to get some RWHP approx. ideas with what I am buying.
LE1 H/C setup.
The cam is a 218/214 .570/.570.
going into a 6.0 with only a custom ram-air, Efans and a tune.
As for the exhaust, I am trying to keep this truck quiet (I will have a newborn), so I am staying away from LTs for now.
Any ideas on the power I might see?
LE1 H/C setup.
The cam is a 218/214 .570/.570.
going into a 6.0 with only a custom ram-air, Efans and a tune.
As for the exhaust, I am trying to keep this truck quiet (I will have a newborn), so I am staying away from LTs for now.
Any ideas on the power I might see?
05-15-2009, 06:39 PM
#2
I'm not the best at guessing RWHP numbers, so I can't help you there. Curious why the reverse split though. (218/214) As far as LT's go, if you get a large case muffler they won't affect the sound level that much. FWIW, my daughter started cruising around in my truck with me when she was 2, and she loves how my truck sounds. When I pull on the highway she says "daddy's truck loud" lol. Congrats on the new addition to your family! 
BTW, if you're not going with a free-flowing exhaust, you're going to want a cam grind that is more exhaust biased
BTW, if you're not going with a free-flowing exhaust, you're going to want a cam grind that is more exhaust biased
05-15-2009, 07:47 PM
#3
Thanks man, I am scared out of my mind, and I can't wait at the same time.
Yeah, I hear you on the noise thing...I also considered that it might be soothing (somewhat) to help put her to sleep.
As for the reverse split, I am following the advice of Lloyd. I am looking for smooth idle manners, good all around power and mass TQ down low, all with the stock converter. He recommended the 218/214. I know there is power left on the table, but it fits for what I am looking for, you know.
Let me ask you this, the "Y" pipe that is on the truck, all things point to a stock system, is not a true Y, its 2 pipes all the way into the factory muffler. That is mildly confusing to me, as I thought they were all true "Y" pipes. Does anyone make a direct replacement LT / "Y" pipe kit that retains the factory configuration?
Yeah, I hear you on the noise thing...I also considered that it might be soothing (somewhat) to help put her to sleep.
As for the reverse split, I am following the advice of Lloyd. I am looking for smooth idle manners, good all around power and mass TQ down low, all with the stock converter. He recommended the 218/214. I know there is power left on the table, but it fits for what I am looking for, you know.
Let me ask you this, the "Y" pipe that is on the truck, all things point to a stock system, is not a true Y, its 2 pipes all the way into the factory muffler. That is mildly confusing to me, as I thought they were all true "Y" pipes. Does anyone make a direct replacement LT / "Y" pipe kit that retains the factory configuration?
Last edited by 03 BLACKOUTSSS; 05-15-2009 at 07:58 PM.
05-15-2009, 09:03 PM
#5
Lloyd Elliot, not BBq. Dyno sheets support his reasoning for suggesting this design.
You say they DO NOT WORK. Why? What was the goal when a rev. split was tried?
I am not trying to snipe what you are saying...more looking for a little insight as to why you say that.
You say they DO NOT WORK. Why? What was the goal when a rev. split was tried?
I am not trying to snipe what you are saying...more looking for a little insight as to why you say that.
05-15-2009, 09:05 PM
#6
Let me ask you this, the "Y" pipe that is on the truck, all things point to a stock system, is not a true Y, its 2 pipes all the way into the factory muffler. That is mildly confusing to me, as I thought they were all true "Y" pipes. Does anyone make a direct replacement LT / "Y" pipe kit that retains the factory configuration?
If you have the cash, it seems like the ARH's are definitely the way to go. They just had a group purchase not too long ago, and I think they're having a sale now.
Man, I remember the feeling before my daughter was born, just like you said, excited but scared to hell. I think that I drove 20mph the whole way home from the hospital when we brought her home lol.
Last edited by budhayes3; 05-15-2009 at 09:12 PM.
05-15-2009, 09:10 PM
#7
Thanks for the info, and the ideas for where to start looking. Do you have any input on what was said above...about the reverse split not working with these motors. I am a bit confused. On one hand, I got Lloyd Elliot suggesting what to use. I figure he knows a little about what he is doind. On the other hand I got HIRDLEJ saying what he said above. I don't want to discredit what hes got to say, because he may be right.
I need more info... :help:
I need more info... :help:
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05-15-2009, 09:27 PM
#8
I agree with Joe, the reverse splits don't seem to be the way to go with the GENIII trucks, especially with any sort of exhaust piping on them. In theory, you'd have to have an exhaust system that is considerably more efficient than the intake to warrant a reverse split. The closest I'd go to a reverse split is a single pattern cam, as many guys around here have done very well with them (the famous TR220 and 224 come to mind).
I've chosen the Vinci Trucker for my LQ9 build, which is 216/224 .551/.551 115. That's 8* exhaust bias, but since I only have 2.5" header collectors and plan to keep the cats, I think it could use a little help exhaling out of the cylinders. Yes, this grind is very mild by the 6.0 standards around here, but perfect for my daily driven needs. I will be using a 2600 converter but could probably even get away with something in the 2200-2400 range. Do you plan a higher stall converter in the future? That will be a factor in your cam choice. Personally, I wouldn't go with a cam any bigger than the Trucker on the stock verter, and even that is a little much IMO. I like to optimize the powerband of the camshaft with the drivetrain. If you are sticking with the stock converter I'd think that something like the tried and true 212/218 .55x/.55x 114 would suit a 6.0.
Speaking of Joe (HirdleJ), I liked the cam specs he used to have on his 6.0, which was 218/224...can't remember the rest...I know that it had over .55x lift though, but can't remember if it was a 212 or 214. A converter in the 2600-3000 range would compliment that cam nicely.
I've chosen the Vinci Trucker for my LQ9 build, which is 216/224 .551/.551 115. That's 8* exhaust bias, but since I only have 2.5" header collectors and plan to keep the cats, I think it could use a little help exhaling out of the cylinders. Yes, this grind is very mild by the 6.0 standards around here, but perfect for my daily driven needs. I will be using a 2600 converter but could probably even get away with something in the 2200-2400 range. Do you plan a higher stall converter in the future? That will be a factor in your cam choice. Personally, I wouldn't go with a cam any bigger than the Trucker on the stock verter, and even that is a little much IMO. I like to optimize the powerband of the camshaft with the drivetrain. If you are sticking with the stock converter I'd think that something like the tried and true 212/218 .55x/.55x 114 would suit a 6.0.
Speaking of Joe (HirdleJ), I liked the cam specs he used to have on his 6.0, which was 218/224...can't remember the rest...I know that it had over .55x lift though, but can't remember if it was a 212 or 214. A converter in the 2600-3000 range would compliment that cam nicely.
05-15-2009, 09:30 PM
#9
Here, read this and learn why reverse splits are a bad idea on an lsx engine.
This is a write up by Bret Bauer of Bauer Racing Engines:
--------------------------------------------------------------------------------
Preface.... The Reverse Split Ideology:
The whole "theory" on why LS engines need a reverse split, that being a cam with more intake duration than exhaust duration is as follows from what I take:
1. My Version: Since a LS motor for example has a 80% E/I ratio in bare form and then when a intake manifold is installed it increases that ratio even more so the exhaust is much more than 75% of the intake, we need to match the to camshaft that flow imbalance hence changing the duration to this configuration.
2. LS1Toke: A reverse split cam is best for someone who has limited mods on the intake side and good mods(such as LT, ORY, and cat-back) on the exhaust side.
3. LS1Toke: A reverse split cam is better for your current application if you don't have the best intake flow and if you have full exhaust. What it does is allow more air into the cylinders. So since you have a LS1 intake you would benefit from it because the flow isnt as good as LS6.
And the real kicker a "Advanced Tech" thread on the matter...
https://ls1tech.com/forums/showthread.php?t=925980
Ok so now I guess we have down that with a good exhaust system like a standard bolt on car has, you now have LOTS of exhaust flow after the head so it's not a restriction to the exhaust flow, but with the intake manifold design of the LS motor you have a choked off intake port since the manifold can't FLOW as much as the cylinder head. Therefore this makes the intake to exhaust ratio flow around something stupid like 90%.
Now on to why this is all horse hockey. (bonus points for who can tell me where I get that from)
Just the FACTS mam:
The people who stumble on this "theory" are comparing data from static flow testing only and basing their choices for a camshaft on things that don't really happen in the working motor.
The first rule here that this is a BS idea is the straight fact that the LS motor makes 100% VE or greater very easily. Engine dyno tests show that a stock LS6 motor for example will make 430HP in stock trim without the accessories on it. That's right at or above 100% VE. Now consider that if the LS6 cam is retarded 2° which is normal, the IVC is around 68° ABDC. So there is only 112° of time when the air/fuel is "trapped" in the cylinder, or 62% of 180°.
So how can a head that can flows 250+ cfm in stock form that is being choked off by a intake manifold make 100%+ VE on top of 346 cubes?
How does it do it in stock form, especially with all the stock cams being "traditional" split cams? 196/202, 201/210, 204/218, 204/211 etc....
The real problem here is that these guys are looking at FLOW, and not the depression or delta P, that is causing that flow in the first place. That leads to looking at the intake manifold, the same flow robbing bandit turns out to be the positive pressure producing part of the motor that is causing 100% VE in stock form! Yep our old buddy pressure wave tuning is rearing his ugly head to make this concept of flow irrelevant to the average Joe's easy thinking.
Pressure Wave Tuning the basic and expanded explaination:
Pressure waves are produced from a Helmholtz resonance, which has best been described as air acting like mass on a spring in the intake port from valve to plenum.
A excerpt from Wikipedia that is good on this...
"Qualitative explanation
When air is forced into a cavity, the pressure inside increases. Once the external force that forces the air into the cavity disappears, the higher-pressure air inside will flow out. However, this surge of air flowing out will tend to over-compensate, due to the inertia of the air in the neck, and the cavity will be left at a pressure slightly lower than the outside, causing air to be drawn back in. This process repeats with the magnitude of the pressure changes decreasing each time.
This effect is akin to that of a bungee-jumper bouncing on the end of a bungee rope, or a mass attached to a spring. Air trapped in the chamber acts as a spring. Changes in the dimensions of the chamber adjust the properties of the spring: a larger chamber would make for a weaker spring, and vice-versa.
The air in the port (the neck of the chamber) is the mass. Since it is in motion, it possesses some momentum. A longer port would make for a larger mass, and vice-versa. The diameter of the port is related to the mass of air and the volume of the chamber. A port that is too small in area for the chamber volume will "choke" the flow while one that is too large in area for the chamber volume tends to reduce the momentum of the air in the port."
Here is a easy to read article that relates this phenomenon closer to internal combustion engines... http://www.dinamoto.it/DINAMOTO/on-l...suonatore.html
Or if you feel like you want to a more direct explaination of all of this it can be found in a paper here titled: The Acoustics of Racing Engine Intake Systems
Very cool paper if you are into super geeky engine stuff!
How all of this works to make HP:
So now that we have the idea that pressure waves going back and fourth between the plenum and valve cause a building and dropping of pressure in the intake port. The tuning of this wave is relative to the length of the tract from plenum to valve and is either very good at certain RPM or very bad and also has a order as to how many times it cycles per engine revolution at that RPM. These are called harmonics....
Harmonics are the key to the strength of the pulse, by reading the excerpt above on Helmholtz resonance you can see that the pressure pulse is stronger the longer the runner. Now each RPM has a length associated with each harmonic. The harmonics going from one to six get weaker with every additional harmonic, the first being the strongest and longest, but you have to calculate the appropriate length relative to RPM and cylinder displacement.
A LS motor works on the 2nd Harmonic so it is a very strong, thus producing high pressure in the intake port. High pressure above a low cylinder pressure creates a large depression.... a lot like a flow bench makes. Now with that idea we can relate this to how the average Joe looks at head data.
This large difference or large depression causes the head to act like it is being flowed on a flow bench at a higher depression than the standard 28" of flow. It can be over 100" of depression on a stock LS6 at HP peak. So now the flow of the intake port in this dynamic environment is much more than the 250cfm or so that the flow bench tell us. Actually around .500" lift where the head statically flows 250cfm @ 28" on a flow bench it actually moves about 320cfm on the running motor.
The only issue with using these numbers is that from IVO to IVC the depression between the head port and cylinder changes and it does so at every RPM as well. Either way this points out that with the 2nd order harmonic that the LS motor works on we fill the cylinder much more than the flow bench data says we can. That's why we can fill the cylinder at or more than 100% VE on a stock motor hence how this all makes HP!
So how does this relate to the "split" of the cam?:
What you put into a motor you have to get out... now since time in camshaft terms is relative to duration we have to get out what we get in. Since there are no restrictions in the system to filling the cylinder and as we have seen the motor does so better than we can imagine due to resonance tuning.
The only issue with the resonance tuning is that it's highly sensitive to the intake valve timing and if we leave the valve open too long the motor will lose what it put into the cylinder (late IVC) or not create enough of a pressure build up to start filling the cylinder well at IVO, so that means we have a set intake duration range that is relative to our working RPM range we can use.... (hence why big cams are wrong for street cars!)
So now since we have a limit on the intake side of the cam since it's a compromise between optimal valve events for a range of RPM, we have to figure out what it takes to get out what the motor put in.
The exhaust side of the motor is much, much harder to guess at. The pressures are very high when the exhaust valve is cracked @ EVO and decays from there until EVC. The flow happening here makes very little sense if any at all to even the best in the industry and flow numbers of a static flow bench tell us little to if anything about what is going on.
Conclusion:
What we do know is that with the added depression that the intake port sees due to the 2nd harmonic pressure pulse we put more in the cylinder during the time the intake valve was open than what the cylinder head statically flows.... so we have to get all of that out, and get it out through a smaller hole!
This simple fact is why you need more duration on the exhaust than on the intake in a LS motor.
This is a write up by Bret Bauer of Bauer Racing Engines:
--------------------------------------------------------------------------------
Preface.... The Reverse Split Ideology:
The whole "theory" on why LS engines need a reverse split, that being a cam with more intake duration than exhaust duration is as follows from what I take:
1. My Version: Since a LS motor for example has a 80% E/I ratio in bare form and then when a intake manifold is installed it increases that ratio even more so the exhaust is much more than 75% of the intake, we need to match the to camshaft that flow imbalance hence changing the duration to this configuration.
2. LS1Toke: A reverse split cam is best for someone who has limited mods on the intake side and good mods(such as LT, ORY, and cat-back) on the exhaust side.
3. LS1Toke: A reverse split cam is better for your current application if you don't have the best intake flow and if you have full exhaust. What it does is allow more air into the cylinders. So since you have a LS1 intake you would benefit from it because the flow isnt as good as LS6.
And the real kicker a "Advanced Tech" thread on the matter...
https://ls1tech.com/forums/showthread.php?t=925980
Ok so now I guess we have down that with a good exhaust system like a standard bolt on car has, you now have LOTS of exhaust flow after the head so it's not a restriction to the exhaust flow, but with the intake manifold design of the LS motor you have a choked off intake port since the manifold can't FLOW as much as the cylinder head. Therefore this makes the intake to exhaust ratio flow around something stupid like 90%.
Now on to why this is all horse hockey. (bonus points for who can tell me where I get that from)
Just the FACTS mam:
The people who stumble on this "theory" are comparing data from static flow testing only and basing their choices for a camshaft on things that don't really happen in the working motor.
The first rule here that this is a BS idea is the straight fact that the LS motor makes 100% VE or greater very easily. Engine dyno tests show that a stock LS6 motor for example will make 430HP in stock trim without the accessories on it. That's right at or above 100% VE. Now consider that if the LS6 cam is retarded 2° which is normal, the IVC is around 68° ABDC. So there is only 112° of time when the air/fuel is "trapped" in the cylinder, or 62% of 180°.
So how can a head that can flows 250+ cfm in stock form that is being choked off by a intake manifold make 100%+ VE on top of 346 cubes?
How does it do it in stock form, especially with all the stock cams being "traditional" split cams? 196/202, 201/210, 204/218, 204/211 etc....
The real problem here is that these guys are looking at FLOW, and not the depression or delta P, that is causing that flow in the first place. That leads to looking at the intake manifold, the same flow robbing bandit turns out to be the positive pressure producing part of the motor that is causing 100% VE in stock form! Yep our old buddy pressure wave tuning is rearing his ugly head to make this concept of flow irrelevant to the average Joe's easy thinking.
Pressure Wave Tuning the basic and expanded explaination:
Pressure waves are produced from a Helmholtz resonance, which has best been described as air acting like mass on a spring in the intake port from valve to plenum.
A excerpt from Wikipedia that is good on this...
"Qualitative explanation
When air is forced into a cavity, the pressure inside increases. Once the external force that forces the air into the cavity disappears, the higher-pressure air inside will flow out. However, this surge of air flowing out will tend to over-compensate, due to the inertia of the air in the neck, and the cavity will be left at a pressure slightly lower than the outside, causing air to be drawn back in. This process repeats with the magnitude of the pressure changes decreasing each time.
This effect is akin to that of a bungee-jumper bouncing on the end of a bungee rope, or a mass attached to a spring. Air trapped in the chamber acts as a spring. Changes in the dimensions of the chamber adjust the properties of the spring: a larger chamber would make for a weaker spring, and vice-versa.
The air in the port (the neck of the chamber) is the mass. Since it is in motion, it possesses some momentum. A longer port would make for a larger mass, and vice-versa. The diameter of the port is related to the mass of air and the volume of the chamber. A port that is too small in area for the chamber volume will "choke" the flow while one that is too large in area for the chamber volume tends to reduce the momentum of the air in the port."
Here is a easy to read article that relates this phenomenon closer to internal combustion engines... http://www.dinamoto.it/DINAMOTO/on-l...suonatore.html
Or if you feel like you want to a more direct explaination of all of this it can be found in a paper here titled: The Acoustics of Racing Engine Intake Systems
Very cool paper if you are into super geeky engine stuff!
How all of this works to make HP:
So now that we have the idea that pressure waves going back and fourth between the plenum and valve cause a building and dropping of pressure in the intake port. The tuning of this wave is relative to the length of the tract from plenum to valve and is either very good at certain RPM or very bad and also has a order as to how many times it cycles per engine revolution at that RPM. These are called harmonics....
Harmonics are the key to the strength of the pulse, by reading the excerpt above on Helmholtz resonance you can see that the pressure pulse is stronger the longer the runner. Now each RPM has a length associated with each harmonic. The harmonics going from one to six get weaker with every additional harmonic, the first being the strongest and longest, but you have to calculate the appropriate length relative to RPM and cylinder displacement.
A LS motor works on the 2nd Harmonic so it is a very strong, thus producing high pressure in the intake port. High pressure above a low cylinder pressure creates a large depression.... a lot like a flow bench makes. Now with that idea we can relate this to how the average Joe looks at head data.
This large difference or large depression causes the head to act like it is being flowed on a flow bench at a higher depression than the standard 28" of flow. It can be over 100" of depression on a stock LS6 at HP peak. So now the flow of the intake port in this dynamic environment is much more than the 250cfm or so that the flow bench tell us. Actually around .500" lift where the head statically flows 250cfm @ 28" on a flow bench it actually moves about 320cfm on the running motor.
The only issue with using these numbers is that from IVO to IVC the depression between the head port and cylinder changes and it does so at every RPM as well. Either way this points out that with the 2nd order harmonic that the LS motor works on we fill the cylinder much more than the flow bench data says we can. That's why we can fill the cylinder at or more than 100% VE on a stock motor hence how this all makes HP!
So how does this relate to the "split" of the cam?:
What you put into a motor you have to get out... now since time in camshaft terms is relative to duration we have to get out what we get in. Since there are no restrictions in the system to filling the cylinder and as we have seen the motor does so better than we can imagine due to resonance tuning.
The only issue with the resonance tuning is that it's highly sensitive to the intake valve timing and if we leave the valve open too long the motor will lose what it put into the cylinder (late IVC) or not create enough of a pressure build up to start filling the cylinder well at IVO, so that means we have a set intake duration range that is relative to our working RPM range we can use.... (hence why big cams are wrong for street cars!)
So now since we have a limit on the intake side of the cam since it's a compromise between optimal valve events for a range of RPM, we have to figure out what it takes to get out what the motor put in.
The exhaust side of the motor is much, much harder to guess at. The pressures are very high when the exhaust valve is cracked @ EVO and decays from there until EVC. The flow happening here makes very little sense if any at all to even the best in the industry and flow numbers of a static flow bench tell us little to if anything about what is going on.
Conclusion:
What we do know is that with the added depression that the intake port sees due to the 2nd harmonic pressure pulse we put more in the cylinder during the time the intake valve was open than what the cylinder head statically flows.... so we have to get all of that out, and get it out through a smaller hole!
This simple fact is why you need more duration on the exhaust than on the intake in a LS motor.
05-15-2009, 09:46 PM
#10
Everything you said there jives with what I know about design theory (limited knowledge), the bulk of what is marketed to us (primarily exhaust biased profiles) and what has been put through the test of time. HOWEVER, I have to give credence to the head porter, as this is his area of expertise. I am going to ask him to chime in here and maybe offer some clarity to this mud pie of opinions.
What I do know is that Lloyd reviewed the dyno sheets of the 218/214 and a TR224 (I think). The small cam made better power and TQ over the big cam until 5000rpm, when the big cam started to shine. I have a feeling that this is a situation where less might be more, in reference to using scavenging 'tactics' as opposed to all out free flowing ideals. The other thing is that I am staying with the factory stall for the time being (long term) and I agree with you, I don't want to have a mismatched setup refering to the cam / converter relationship.
What I do know is that Lloyd reviewed the dyno sheets of the 218/214 and a TR224 (I think). The small cam made better power and TQ over the big cam until 5000rpm, when the big cam started to shine. I have a feeling that this is a situation where less might be more, in reference to using scavenging 'tactics' as opposed to all out free flowing ideals. The other thing is that I am staying with the factory stall for the time being (long term) and I agree with you, I don't want to have a mismatched setup refering to the cam / converter relationship.