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Peon Extraordinaire
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So I am wondering what the benefit of a Cam on a powerstroke is? Does anyone have any factual data to back up any claim? What kind of gain would you see with one?

Do they do anything - really?

Sam
 

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Peon Extraordinaire
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Discussion Starter #3
I was hoping for feedback from someone not trying to sell a Cam...

Sam
 

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Wasn't trying to sell anything give him a call or ask him a few questions. Just trying to point you to somebody that may know! There have been quite a few responses in that thread. Try sending a pm to some of the people that have or have ran a cam.
 

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Crazy Talk
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i ran one in my blown motor and when i had my motor built i felt it was worth it to get another one.
 

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Discussion Starter #6
Wasn't trying to sell anything give him a call or ask him a few questions. Just trying to point you to somebody that may know! There have been quite a few responses in that thread. Try sending a pm to some of the people that have or have ran a cam.
I am sorry - I didn't mean to imply that you were trying to sell something. I meant Matt is trying to sell something in his thread. I was trying to see if people in the real world had knowledge/experience they would share. Similar to powerstrokenstang's post. I appreciate the post, I read the entire thread and then all of the linked threads in it. Had some really good information.

Sam
 

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There are several that have ran them, most seem to like them. From what I have read, I don't however have any personal experience running a cam. I would like to try one though to see if it is something I would like for a daily driven application.
Wasn't trying to come across as pi$$ed off or anything! :ford:
 

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I am sorry - I didn't mean to imply that you were trying to sell something. I meant Matt is trying to sell something in his thread. I was trying to see if people in the real world had knowledge/experience they would share. Similar to powerstrokenstang's post. I appreciate the post, I read the entire thread and then all of the linked threads in it. Had some really good information.

Sam
We will know some more results in the comming weeks. The stage 1 is doing well right now. So far the cam is doing everything I wanted it to and some things I didn't count on as well. I took a different approach than what's been done before but knew what to expect. So far:
Positives-
Lower EGTs when cruising and under load
Broader powerband
Lower boost at WOT (keeping turbo in it's map)
No loss in drivability above 1200 rpms.
Possible mileage increase due to lower pumping losses and better Volumetric Effeciency at cruise RPMs (will need more testing to verify).

Negatives-
Lower dynamic compression at idle that must be tuned out with a little extra timing compared to the stock cam. This goes away by 1000 rpms.
 

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This could be a really good discussion if it was filled with facts about how a cam works and not opinions. I will be the first to admit that I have very little knowledge when it comes to this subject. It seems as there must be some black magic to it or something. I would love for some of the old farts around here that have the knowledge to share it.
 

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This could be a really good discussion if it was filled with facts about how a cam works and not opinions. I will be the first to admit that I have very little knowledge when it comes to this subject. It seems as there must be some black magic to it or something. I would love for some of the old farts around here that have the knowledge to share it.
The problem is that everything that usually applies to cams doesn't work on the 7.3 because of it's unique construction. On diesels in general you can move the powerband up just like a gasser but you must pay special attention to things because you have compression ignition. The more duration you add, the more you have to deal with overlap (bad) and/or loss of cylinder pressure (also bad) in the lower rpms. The goal is get the right amount of airflow in the range you want to make peak power and nothing more. But I can tell you this, for the size of the engine we have the stock cam isn't enough to let the engine breathe properly even with ported heads. It's always a compromise though, you are basically taking away bottom end to gain top end. The trick is moving the VE of the engine enough to make a difference while not moving it enough to hurt drivability in the desired rpm range. Even in the gasser world, everyone has to install a higher stall converter if they want to make peak power at 6000 rpms. I don't think it is worth it though for someone to have a 3000 stall converter on a street diesel LOL. I just want to see a 7.3 start carrying some torque out to 3000+ RPMs instead of doing the grand canyon we are used to seeing.
 

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Plays with Motors
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Volumetric efficiency.....


Like you said, that is the reason for the torque/horsepower nose-dive because we see it on the dyno all the time, get the air in the cylinder and it will go away.

I'm not sure what exactly you are doing with the lobes on the cam but posting some cam doctor data would help as I would like to see what the .006", .050", and .200" numbers are to get a better idea of your ramp intensity. That is where the gains will be made - get the valves opened as fast as possible and keep the overlap out like you had said. This obviously creates problems controlling the valve train with the valve acceleration being so fast but the hypermax springs give enough pressure to get it done without allowing valve float especially with the low rpms.

On the right path :D
 

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Volumetric efficiency.....


Like you said, that is the reason for the torque/horsepower nose-dive because we see it on the dyno all the time, get the air in the cylinder and it will go away.

I'm not sure what exactly you are doing with the lobes on the cam but posting some cam doctor data would help as I would like to see what the .006", .050", and .200" numbers are to get a better idea of your ramp intensity. That is where the gains will be made - get the valves opened as fast as possible and keep the overlap out like you had said. This obviously creates problems controlling the valve train with the valve acceleration being so fast but the hypermax springs give enough pressure to get it done without allowing valve float especially with the low rpms.

On the right path :D
I can't give out those numbers because that is part of the reason they will work as good as they do, but let's just say that they are quite a bit more aggressive than stock as far as the ramp rates go. Let's just say that the duration at .050 grew more than the seat timing on the stage 1 over stock. That's also why I am mandating 125-150 lbs of seat pressure on the springs. The opening rate is very fast and the closing ramps are more gentle. I bounced my numbers off the grinder and they even made some some adjustments to the ramps, but we settled on something that will work for its intended purpose. The stage 2 actually has a slower lobe ramp rate since its intended rpm range is higher than the stage 1.
 

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Grumpy Old Bitter Bastard
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I can't give out those numbers because that is part of the reason they will work as good as they do, but let's just say that they are quite a bit more aggressive than stock as far as the ramp rates go. Let's just say that the duration at .050 grew more than the seat timing on the stage 1 over stock. That's also why I am mandating 125-150 lbs of seat pressure on the springs. The opening rate is very fast and the closing ramps are more gentle. I bounced my numbers off the grinder and they even made some some adjustments to the ramps, but we settled on something that will work for its intended purpose. The stage 2 actually has a slower lobe ramp rate since its intended rpm range is higher than the stage 1.
There lies the problem with any discussions on cams or anything that might be a performance gain to these engines. Everyone is out for there dollars. Matt, when you have a proven and dyno'd cams, just post up in your vendor section. No need for discussion in this forum since you have nothing to offer to discuss. There are several other cams out there that work very well, but those won't be discussed either. As is always the case here - worthless thread...
 

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How is this a worthless thread? I am also willing to admit i dont know anything about cams, and am very willing to learn. Even tho the exact numbers werent given (which i dont think in would either), i still find it educational learning about ramp rates etc.
 

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There lies the problem with any discussions on cams or anything that might be a performance gain to these engines. Everyone is out for there dollars. Matt, when you have a proven and dyno'd cams, just post up in your vendor section. No need for discussion in this forum since you have nothing to offer to discuss. There are several other cams out there that work very well, but those won't be discussed either. As is always the case here - worthless thread...
What I am saying about this is that we are very limited by our cams. It's apparent that although many have had 10+ years working with this platform, only a few people have figured out why these motors don't breathe worth a sh*t compared to every other diesel motor on the planet. I could tell you what I did with overlap, duration, lobe separation, lobe centerline, and lobe aggressiveness but what would that do for the consumer? The light bulb might come on for someone else that hasn't done the homework to be where I am with this stuff.

It's sad that there are so many cams on the market for the 7.3 that don't work. I know of only 2 that have ever shown promise and one of them is David's and the other is the one Johnboy was running in his pulling truck. Every other platform has aftermarket cams that do what they are supposed to do. Does that mean the stock 7.3 cam is perfect? HELL NO it is a joke for anyone wanting over 500HP. It just doesn't move the air and the numbers say so. If you look at the fact that this engine's peak VE is around 1800-1900rpm's with the stock cam, it all starts to make sense...... Go look at any high horsepower 7.3 with a stock cam..... where does the torque start to sign off? No matter where the level of power is, the RPM where the torque signs off and the horsepower goes flat is almost exactly the same.

I am not in this to get rich, but I don't want to give it away either since evidently so few have been able to be successful with this. If you want more information about specifics you can drop me a pm instead of calling me out here. If you want to see what is going on, look at the peak head flow numbers then look at what the valve lift is doing compared to piston position during the intake and exhaust strokes. Then look at spare valve clearance (none). Now compare what you came up with on a similar engine cubic inch-wise and look at what duration it takes to have its powerband in the desired rpm-range. Now look at our pathetic duration and ramp rate. Now you can come to the same decision I did on the cam.
 

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I don't think anyone is in business to lose money, so that's in invalid argument. Regardless, Matt wanting to keep specifics to himself does not mean his input is not appreciated nor helpful. He has dedicated a lot of time and effort towards something that most were telling him was a waste of his time. Are site sponsors disqualified from giving general advice/information to the general public?
 

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What I am saying about this is that we are very limited by our cams. It's apparent that although many have had 10+ years working with this platform, only a few people have figured out why these motors don't breathe worth a sh*t compared to every other diesel motor on the planet. I could tell you what I did with overlap, duration, lobe separation, lobe centerline, and lobe aggressiveness but what would that do for the consumer? The light bulb might come on for someone else that hasn't done the homework to be where I am with this stuff.

It's sad that there are so many cams on the market for the 7.3 that don't work. I know of only 2 that have ever shown promise and one of them is David's and the other is the one Johnboy was running in his pulling truck. Every other platform has aftermarket cams that do what they are supposed to do. Does that mean the stock 7.3 cam is perfect? HELL NO it is a joke for anyone wanting over 500HP. It just doesn't move the air and the numbers say so. If you look at the fact that this engine's peak VE is around 1800-1900rpm's with the stock cam, it all starts to make sense...... Go look at any high horsepower 7.3 with a stock cam..... where does the torque start to sign off? No matter where the level of power is, the RPM where the torque signs off and the horsepower goes flat is almost exactly the same.

I am not in this to get rich, but I don't want to give it away either since evidently so few have been able to be successful with this. If you want more information about specifics you can drop me a pm instead of calling me out here. If you want to see what is going on, look at the peak head flow numbers then look at what the valve lift is doing compared to piston position during the intake and exhaust strokes. Then look at spare valve clearance (none). Now compare what you came up with on a similar engine cubic inch-wise and look at what duration it takes to have its powerband in the desired rpm-range. Now look at our pathetic duration and ramp rate. Now you can come to the same decision I did on the cam.
Oh and I forgot, you must be aware of the consequences of your changes as well..... too much duration or the lobe centerline in the wrong place (like stock) and you will make less power than stock in some places.
 

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Can anyone post the specs for the stock cam (.050 dur, lift at valve, lsa)?
 

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I'll say this, until people start understanding that it's a combination of parts not just one part by itself that makes a difference, cam threads will be just like injector and turbo threads.
I had a guy tell me my cam didn't make a bit difference in his truck:doh:
 
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