The Truth on Cam Advertised Duration, Etc.

[spoolin ddub]

Thats why i asked if someone has the actual specs at one or the other from someone that has thrum .050 Or 1mm

i guess i didn't read the article from dsport

I advise everyone to at least read it. I'm not saying the companies are lying because they aren't. But you have see how much different the numbers at the cam are....from how the companies test them.

 

[lasthope05]

I advise everyone to at least read it. I'm not saying the companies are lying because they aren't. But you have see how much different the numbers at the cam are....from how the companies test them.

Definitely a good read. It's also nice to get more info on GSC r2 cams. Those cams are nasty.

I have I say though, I spent more time reading about the FA20 disassembly, .

 

[spoolin ddub]

Definitely a good read. It's also nice to get more info on GSC r2 cams. Those cams are nasty.

I have I say though, I spent more time reading about the FA20 disassembly, .

I read everything. The supra. the honda. That entire magazine is sick. I even found a few misprints and spoke to dsport .


Speaking on the R2. People have told me that they know DSM's running the R2's. I find that funny. I spoke to GSC several times last year and the R2 was not available for DSM's. Why? because the GSC DSM billet core is not big enough to support a cam with 12mm lift. I also spoke to GSC at 7:30am this morning to confirm the info is still accurate. It is. Maybe in a year or so though .

 

[LandSpeed-DSM]

I advise everyone to at least read it. I'm not saying the companies are lying because they aren't. But you have see how much different the numbers at the cam are....from how the companies test them.

Have you had your head on a flow bench before? It's not lab quality information, but it's better than nothing.

The previous 1G head on this short block produced these numbers on #3 intake runner with light port and polish at 28" vacuum using a 4 liter plenum with ~5" stacks:

Lift CFM
.050 60.38
.100 106.30
.150 161.19
.200 187.97
.250 241.11
.300 270.10
.350 298.19
.400 309.45
.450 320.31
.500 334.25
.550 345.98
.600 357.32
.650 365.21
.700 374.46

Some food for thought.. current cams (S3s) have a gross lift of ~0.460"

 

[spoolin ddub]

Have you had your head on a flow bench before? It's not lab quality information, but it's better than nothing.

The previous 1G head on this short block produced these numbers on #3 intake runner with light port and polish at 28" vacuum using a 4 liter plenum with ~5" stacks:

Lift CFM
.050 60.38
.100 106.30
.150 161.19
.200 187.97
.250 241.11
.300 270.10
.350 298.19
.400 309.45
.450 320.31
.500 334.25
.550 345.98
.600 357.32
.650 365.21
.700 374.46

Some food for thought.. current cams (S3s) have a gross lift of ~0.460"

I have not. But my next head I may. Not to big on that.

 

[LandSpeed-DSM]

I have not. But my next head I may. Not to big on that.

What about measuring your drive pressure? (EMAP)

That would be more valuable information, you can use this to manipulate cam timing as well as determine if you are leaving power on the table with either your turbine housing or exhaust system, or identify potential problems.

Pretty cheap to setup too

 

[lasthope05]

I read everything. The supra. the honda. That entire magazine is sick. I even found a few misprints and spoke to dsport .


Speaking on the R2. People have told me that they know DSM's running the R2's. I find that funny. I spoke to GSC several times last year and the R2 was not available for DSM's. Why? because the GSC DSM billet core is not big enough to support a cam with 12mm lift. I also spoke to GSC at 7:30am this morning to confirm the info is still accurate. It is. Maybe in a year or so though .

Im sure there are a few dsms running them. I was looking into them for a Stroker build. All you need are aftermarket cam gears and to slot/drill the intake cam to run them in a dsm. There just wasn't much info bout them out there because of how new they are.

 

[Archer Fabrications]

What about measuring your drive pressure? (EMAP)

That would be more valuable information, you can use this to manipulate cam timing as well as determine if you are leaving power on the table with either your turbine housing or exhaust system, or identify potential problems.

Pretty cheap to setup too

Pm'd on the back pressure logging. I want to do this.

 

[spoolin ddub]

What about measuring your drive pressure? (EMAP)

That would be more valuable information, you can use this to manipulate cam timing as well as determine if you are leaving power on the table with either your turbine housing or exhaust system, as well as identify other problems.

Pretty cheap to setup too

Machine shop that I go to pretty on point. I don't worry about those things to that much. Maybe If I were strictly race car trying to get every single ounce of power but Its still a street car. Car has little lowend power but up top it begs to rev past 10k. I'm happy with that.

Im sure there are a few dsms running them. I was looking into them for a Stroker build. All you need are aftermarket cam gears and to slot/drill the intake cam to run them in a dsm. There just wasn't much info bout them out there because of how new they are.

the billet cores GCS use to grind the DSM cam are not big enough for an R2. I know sponsored DSM cars who want to run an R2 and can't. The evo billet cores are bigger. GSC said maybe an R2 cam for DSm by next year. Some issue with the cores is also one of the reasons FP stop making the DSM FP 5R.

 

[lasthope05]

Machine shop that I go to pretty on point. I don't worry about those things to that point. Maybe If I were strictly race car trying to get every single ounce of power. But Its still a street car. Car has little lowend power but up top it begs to rev past 10k.

the billet cores GCS use to grind the DSM cam are not big enough for an R2. I know sponsored DSM cars who want to run an R2 and can't. The evo billet cores are bigger. GSC said maybe an R2 cam for DSm by next year.

I guess I should of clarified. To use the evo 8 GSC r2 cams one would only have to drill and slot the intake cam for the 1g cas and use adjustable can gears with both evo and dsm dowel locations.

 

[spoolin ddub]

I guess I should of clarified. To use the evo 8 GSC r2 cams one would only have to drill and slot the intake cam for the 1g cas and use adjustable can gears with both evo and dsm dowel locations.

Ok. That's is a different story .

 

[bastarddsm]

Have you had your head on a flow bench before? It's not lab quality information, but it's better than nothing.

The previous 1G head on this short block produced these numbers on #3 intake runner with light port and polish at 28" vacuum using a 4 liter plenum with ~5" stacks:

Lift CFM
.050 60.38
.100 106.30
.150 161.19
.200 187.97
.250 241.11
.300 270.10
.350 298.19
.400 309.45
.450 320.31
.500 334.25
.550 345.98
.600 357.32
.650 365.21
.700 374.46

Some food for thought.. current cams (S3s) have a gross lift of ~0.460"

The problem is this only looks at the flow at a certain depression. You have no idea what the head does at depressions close to what occurs during a cycle. It could be on the order of 100" h20. The relation of flow to depression is not linear.

The flow bench does not take into account the dynamic tuning of the runners either.


This whole thread is dumb. You want to know what cams are best for your setup, exhaustively test them all, then you can say that on this setup xx cam is better. But you still cannot make a statement that xx cam is better than yy cam by looking at the specs.

 

[spoolin ddub]

This whole thread is dumb. You want to know what cams are best for your setup, exhaustively test them all, then you can say that on this setup xx cam is better. But you still cannot make a statement that xx cam is better than yy cam by looking at the specs.

this thread is not dumb. its about having accurate info and putting cams in their correct categories. Then choosing from there. It actually could help save time because its a whole lot of inflated and some deflated numbers y'all going off of .

 

[LandSpeed-DSM]

The problem is this only looks at the flow at a certain depression. You have no idea what the head does at depressions close to what occurs during a cycle. It could be on the order of 100" h20. The relation of flow to depression is not linear.

The flow bench does not take into account the dynamic tuning of the runners either.

I agree with all of that.

It's why I had my old head put on the bench after i worked it over and chose 3 different cam sets to try on the 59mm build, which was also subjected to trial with two different intake manifolds, four different exhaust manifolds and turbine housings.

Because I have a lot of questions (still do) but not enough budget to pursue them all to the degree I'd like, there was a lot learned but nothing i could call conclusive.

Which is why I refer to these as hypotheses, as happened in my initial post in this thread.

Observation and data relative to my setups past and present suggest that I would not want my current cams, their I/E gear adjusments and my sheet metal intake manifold mated with a T25 hanging from a stock exhaust manifold breathing through a stock exhaust system.

Full CFD analysis would be nice, but the rudimentary tools I have available are not entirely useless.

I get what you are saying however.

/Welcome back, by the way!

 

[keltalon]

this thread is not dumb. its about having accurate info and putting cams in their correct categories. Then choosing from there. It actually could help save time because its a whole lot of inflated and some deflated numbers y'all going off of .

Dub do you think some advertised durations are being inflated?

 

[spoolin ddub]

Dub do you think some advertised durations are being inflated?

Not inflated as in just making up a number but maybe its they way they are being tested. I don't know. I just know from what I have seen numerous times. Some cams real numbers are bigger then what they claim and others are smaller. But not one of them match what you see on the cam card. NONE!

 

[bastarddsm]

The problem of this is that long ago people were going 8's at 160 on HKS272's and T61 O trims. Now adays everyone runs 40r+ sized turbo's to maybe get 9's and then bicker over if kelford or GSC or bc cams are better. It is dumb.

I'll also tell you this, in another world where guys run the turbo to the absolute max, I know a guy who owns a dyno shop and spends lots and lots of time on his engine. One year he had several custom cams ground, in wildly varying specs. it was 25hp on 1300hp from best to worst, and the stock cam for the engine was only 100hp down from the best. The 4g63 equivalent of doing what he did was trying ever cam from a hks272, to the biggest cam made on a maxed out 35R setup. So now tell me why the truth in the duration is worth arguing over. I also tell you this, we have change compressor wheels, and picked up over 100hp on 1300. The only thing that was changed was the blade profile, not the ind/exd dimensions.

 

[spoolin ddub]

The problem of this is that long ago people were going 8's at 160 on HKS272's and T61 O trims. Now adays everyone runs 40r+ sized turbo's to maybe get 9's and then bicker over if kelford or GSC or bc cams are better. It is dumb.

I'll also tell you this, in another world where guys run the turbo to the absolute max, I know a guy who owns a dyno shop and spends lots and lots of time on his engine. One year he had several custom cams ground, in wildly varying specs. it was 25hp on 1300hp from best to worst, and the stock cam for the engine was only 100hp down from the best. The 4g63 equivalent of doing what he did was trying ever cam from a hks272, to the biggest cam made on a maxed out 35R setup. So now tell me why the truth in the duration is worth arguing over. I also tell you this, we have change compressor wheels, and picked up over 100hp on 1300. The only thing that was changed was the blade profile, not the ind/exd dimensions.

Stock cam only 100whp down from wildest cam? ok. That other world you talking about can stay where it's at . Because it aint this 4G63 world!! Go find the Devin tuned evo dyno going from a Jun 272 to GSC S3's and see how much it gained. I also know of people personally who have gained 100whp swapping from moderate to aggressive cams. Then go look at the dsport article. You'll see how much whp was gained going from the stock evo 8 cam (which is right at a DSM HKS 272) up to the Tomei 290's. It gained 157whp still rising...... but stopping at 8500rpm. This is the word we are in. And it isn't all about whp either. It's about the setup and powerband also.


And for the compressor wheel statement. Come on now. I expect more from you. A cam has only so many profile designs. Then there is the theory of single and dual patterns but due to our heads even then the cam is limited to it's specs. How many DSM do you know of or even have heard of that are running a cam with over .500" of lift? Now a turbo is the complete opposite. Especially with the compressor wheel. Even if the exducer & inducer are the same. The design of the blade profile is almost limitless!!! The blade can be taller, it can shorter but be at more of an angle, or they can change the game like BW and add extended tip technology.

My point is this. its not the end all. You can go off incorrect info and dyno all day. But I feel it is better to know where you are starting from with the cams real numbers than to not know them.

 

[boost97gst]

Where the hell do i get dsport mag? I dont want a sub, just this copy. Where you guys finding it? Walmart?
I have not checked yet but dont want to make a trip for nothing.

 

[spoolin ddub]

Where the hell do i get dsport mag? I dont want a sub, just this copy. Where you guys finding it? Walmart?
I have not checked yet but dont want to make a trip for nothing.

The only place I've seem it is walmart. But hurry they selling out fast!!!

 

[boost97gst]

Sweet, im heading up there after work today. This is interesting stuff. I know so very little about cams. I need to learn for my next build. My choices should be pretty simple: I want to rev to 10k on a 2l. Big cams are in my future i would guess.

 

[spoolin ddub]

Sweet, im heading up there after work today. This is interesting stuff. I know so very little about cams. I need to learn for my next build. My choices should be pretty simple: I want to rev to 10k on a 2l. Big cams are in my future i would guess.

This last issue had awesome cam info but this issue still has some good stuff. They do a lot of intensive testing. They even have a shock/strut dyno.

 

[bastarddsm]

My point is this. its not the end al. You can go off incorrect info and dyno all day. But feel it is better to know the cams real numbers than not.

Lol, well my car makes damn near as much power as yours does on a baby 30R sized turbo, and weak ass regrind HKS272's....Guess I know something you or the shops that built your car don't know.

 

[spoolin ddub]

Lol, well my car makes damn near as much power as yours does on a baby 30R sized turbo, and weak ass regrind HKS272's....Guess I know something you or the shops that built your car don't know.

That mean nothing. I'm only running 29psi and at 10* of peak timing but making 89whp and 52ft/lbs more at 6psi less... and the fun hasn't even started it yet . But even the whp numbers can be deceiving because of the cars powerband. It's not just about whp. If I choose to I promise you I can rev to 11k. Will I? No. But I may raise it to 10k with rev limit at 10.5k.

But once again what you stated has nothing to do with cams. Stop making this about me and you and reply to my pm.

 

[LandSpeed-DSM]

The problem of this is that long ago people were going 8's at 160 on HKS272's and T61 O trims. Now adays everyone runs 40r+ sized turbo's to maybe get 9's and then bicker over if kelford or GSC or bc cams are better. It is dumb.

I'll also tell you this, in another world where guys run the turbo to the absolute max, I know a guy who owns a dyno shop and spends lots and lots of time on his engine. One year he had several custom cams ground, in wildly varying specs. it was 25hp on 1300hp from best to worst, and the stock cam for the engine was only 100hp down from the best. The 4g63 equivalent of doing what he did was trying ever cam from a hks272, to the biggest cam made on a maxed out 35R setup. So now tell me why the truth in the duration is worth arguing over. I also tell you this, we have change compressor wheels, and picked up over 100hp on 1300. The only thing that was changed was the blade profile, not the ind/exd dimensions.

Couple things.. Trap is going to be best correlated with power.. you know that.

If you are running low 10s @ 145mph you have the power to weight down, but there is much to be developed between the chassis and driver. So I'm not sure what this is supposed to be illustrative of with regard to the cam discussion.

For a setup that's objectively maxed on the turbo.. be it the compressor or turbine side, I would not expect a cam to pick up much power. Why would you? At that point it has become the bottle neck to inhale or exhale through at that, granted with enough bypass you can work around the turbine to an extent but once you have dealt with removing the exhaust as efficiently as possible.. that's it.

If your combination of VE/Displacement/RPM and PR put you in the choke region of either wheel, that's all she can give you unless you have found a way to change your DA on demand

You are talking about what sounds like a form of racing where among other regulations the compressor inlet size is restricted (Pulling) and I suspect you know why that is not fully applicable to a general cam discussion.

In playing with the cams, you state he found 25whp he otherwise would not have. In his case @ 1300HP it likely was very expensive in terms of $/HP. But it's all those marginal gains that lead to a winning program, if you can afford the R&D.

Would it be a safe guess that this is a diesel as well? Where does that redline exactly? At 4500rpm to go from 1300 to 1325, you'd need to pick up about 30wtq. I hear that some of those big mills are turning well north of 5k now. Maybe that's just the alcohol burners?

That's actually fairly impressive given that the same increase on a 1300HP 2.0L spinning in the neighborhood of 10k rpm.. you would only have to gain ~12Lb-Ft to make an additional 25HP.

Meanwhile, for my sport as an example.. I am only limited by displacement, fuel and chassis. Nearly everything else is up for grabs.

Because of my need for a high terminal speed, I need power well past most folks redline. It's pretty obvious that not just any cam will do at >9k.

Since I am not restricted in turbo or by really anything other than swept volume in the block, and will likely end up with something in the 80mm+ range (thinking an 82mm Borg or similar) eventually, the manifolds/head and cam are my bottleneck.

Do you not agree that just as a function of the relationship of power, torque and engine speed... that one would be leaving a lot on the table running a set of stock manifolds and "256" duration cams with an 82mm compressor where the Turbo will have plenty to give for several thousand rpm after the point where VE of the stock top-end will have taken a nose dive?

If you can stay on the compressor map at 105% VE for your displacement to 11k RPM but have a cam that is basically tapped out by 7.5k, it's not exactly a leap to say there is potential to make a lot more power from one that is in it's sweet spot at the engine speed.

500wtq @ 7500rpm = ~715whp
500wtq @ 9500rpm = ~905whp
500wtq @ 11000rpm = ~1050whp

Lol, well my car makes damn near as much power as yours does on a baby 30R sized turbo, and weak ass regrind HKS272's....Guess I know something you or the shops that built your car don't know.

For comparison.. I'm on a tired 1G Rod/Piston bottom end running 25psi, rich and timing in the low teens.. Not really leaning on it at the moment to make that figure.