Looking at Cams, which ones?

[cantfindausername]

Wouldn't having a lower ramp rate actually decrease the effective duration though?

[cantfindausername]

This is something i found on the net while searching into cam specs.

"CAM PROFILE INTENSITY" and "SPAN" WHAT DO THEY MEAN ?


One of the secrets of raising horsepower without sacrificing low speed and mid-range torque is in selecting the right high performance camshaft. That means matching the cam to the speed range in which an engine operates. In spite of the fact that some people believe bigger is better, it is often true that less duration means more usable torque and horsepower.
Before cam duration can be matched to an engines operating range, the exact cam lift must be specified at where the duration is computed. If a statement is made "this cam has 260 degrees of duration", without adding "260 degrees at .050", the duration number of 260 degrees is TOTALLY USELESS.
That's why knowledgeable engine builders usually select a camshaft based on its duration at .05000" cam lift. In addition to being more accurate than "advertised duration" as an indication of a cam's performance potential, duration at .05000" lift applies almost universally, regardless of camshaft make, model or manufacturer.
"Advertised duration" varies depending upon who wrote the advertising. Most original equipment manufacturers (OEM'S) duration specifications for their hydraulic camshafts are specified at something less than the .00400" tappet lift suggested by SAE standard J-604 5.1. Other firms compute duration at .00600" or .00800" of cam lift.
With mechanical lifter racing profiles, advertised durations are usually computed at .01800", .02000" or .02200" of lift. As is the case with hydraulic profiles, advertised durations of mechanical and roller tappet cams can be compared only if the timing cam lift data point baselines are the same.
There are a number of reasons that a hydraulic lifter cam may have its duration computed at something other than .00400" cam lift. In some instances, a cam grinder who has used an exacting timing point for many years may be reluctant to change.
Another sound reason is that new technology can alter performance relative to duration at .00400" lift. Using a different timing point baseline in the computation of advertised duration may therefore be instrumental in reducing the tendency to over cam an engine. But most commonly, duration is rated at a nonstandard lift point as a means of enhancing specifications as compared to those of a competitive cam.
As an example, if one company has a popular racing hydraulic camshaft that has an advertised duration (computed at .00400" cam lift) of 302 degrees, a competitive cam grinder may think that his cam will sell better if it is advertised as having more than 302 degrees of duration. This caters to the "bigger is better" philosophy. Therefore, the competitive cam may be rated at .00200" lift, in which case its duration could be 308 degrees.
At the other end of the spectrum, with cams designed for use in mild street engines, or intended to enhance fuel economy, a manufacturer may rate its hydraulic cams at .006" tappet lift. When specifications are listed, this will make the cam appear "shorter" (have less duration) than those of the competition.
For mild street applications, less duration is frequently more desirable. So again, by playing the numbers game, a manufacturer can make its line of cams seem more attractive than those produced by other cam grinders.
Another point to consider is that with an underrated advertised duration, a cam will appear to be producing surprisingly more horsepower than an "equivalent" profile from a competing manufacturer. In fact, what you have is not a valid comparison because two cams with similar advertised durations will have considerably different ACTUAL valve timing, if their durations are not computed at the same amount of cam lift.
With all the variations in timing point baselines, making cam duration comparisons can be more confusing than trying to figure who's really doing what to whom in a television soap opera!
When comparing camshaft specifications, the best way to cut through the confusion is to focus on duration at .050" lift and lobe separation. These two figures will provide a solid indication of a cam's performance characteristics.
There are three other specifications that are very important. I call them "HYDRAULIC INTENSITY", "MINOR INTENSITY and "MAJOR INTENSITY". These terms were developed as a means of evaluating a camshaft's BROAD RANGE operational efficiency.
HYDRAULIC INTENSITY may be computed by subtracting duration at .05000" cam lift from duration at .00400" cam lift.
A cam with a duration of 280 degrees @.00400" cam lift and a duration of 220 degrees at .05000" cam lift has a HYDRAULIC INTENSITY of 60.00 degrees.
MINOR INTENSITY may be computed by subtracting duration at .05000" cam lift from duration at .01000" cam lift.
MAJOR INTENSITY may be computed by subtracting duration at .05000" cam lift from duration at .02000" cam lift.
In my personal opinion, the smaller the INTENSITY numbers measure, the performance will INCREASE!
The ideal cam profile would raise the valves to full lift instantly, hold them open for a specified duration and then close them instantly. The laws of physics make it impossible to achieve instantaneous valve opening and closing, but recent advancements in design technology have made it possible to open and close the valves with more area under the lift curve. By so doing, engine efficiency is improved because the valves spend less time at very low lift.
In practical terms, if two cams with similar lobe designs have the same duration at .05000" lift, maximum torque and horsepower will be almost identical. However, the cam with the smaller HYDRAULIC, MINOR or MAJOR INTENSITY figure will have a smoother idle, better off-idle response, superior low speed drivability and a broader power curve.
Viewed from another perspective, a lower HYDRAULIC, MINOR or MAJOR INTENSITY number translates to more low end power, without any loss of top end power. It also means that with a highly modified engine, it may be practical to install a cam with slightly longer duration at .05000" cam lift that might otherwise not be practical.
This lower INTENSITY solves many problems of poor idle quality which may effect Computer Controlled engines. Compatibility problems with torque converter stall speeds are also minimized.
State-of-the-art lobe designs therefore, deliver "MORE CAM" per dollar because they produce more power over a wider rpm band.
Now let me try to explain SPAN. I define SPAN with the following notation:
(00.00/00.00)
If a profile is SYMMETRICAL the numbers on each side of the / will be the same. Example, a mechanical tappet profile with a MAJOR INTENSITY of 34.00 degrees would have a MAJOR INTENSITY SPAN of (17.00/17.00).
If this profile was NON-SYMMETRICAL with the same MAJOR INTENSITY of 34.00 degrees the MAJOR INTENSITY SPAN could be (16.00/18.00), (15.00/19.00) or possibly (14.50/19.50).
Almost all HYDRAULIC lifter profiles are NON-SYMMETRICAL and the numbers on each side of the / will be DIFFERENT. Example, a hydraulic lifter profile with a HYDRAULIC INTENSITY of 56.00 degrees could have a HYDRAULIC INTENSITY SPAN of (24.00/32.00). These are the PUBLISHED numbers from the HMV series of profiles (HMV means "Hydraulic Maximum Velocity") from the cam manufacturer on Fentress Boulevard in Daytona Beach, Florida.
Remember that the SPAN numbers inside of the two brackets MUST add up to the TOTAL INTENSITY.
"HAPPY CAM ANALYSIS TO YOU"

[V8Killer]

Wouldn't having a lower ramp rate actually decrease the effective duration though?

No...the duration will still be the same.

Duration is effectively how long the valve is opened for in relation to crankshaft rotation. So, a cam specification of 272 degrees duration simply means the cam holds the valve open for 272 degrees of crankshaft rotation. I think thats the idea anyway

There was a post about it on MR2OC US...again by Flupstar, who explained the differences between a set of HKS and Jun cams, side by side!

[cantfindausername]

Yeah but from whats written above, that 272 means next to nothing. The measurement should be given from 1mm lift.

I think its a good point that they dont give that value. Makes you wonder how much actual research and testing goes into their cam design, or if they just say, "yeah that'll do, call it a 272"

[MR2Mania]

Yeah but from whats written above, that 272 means next to nothing. The measurement should be given from 1mm lift.

Exactly, mate, and there was once a post my NoShoes on the MR2OC showing the durations at 1mm lift, and it made good reading.

In fact, the article that you posted says it all. The problem is, cam manufacturers don't like to quote these figures because it gives the game away as to how they've designed their cams.

I think its a good point that they dont give that value. Makes you wonder how much actual research and testing goes into their cam design, or if they just say, "yeah that'll do, call it a 272"

The thing is, nearly all the manufacturers have ranges called "256", "264", "272", etc, when in fact (as you state) you can't really relate this to anything. It's a marketing thing, I guess, that helps the user to compare one company's cam to another.

The fact that Muhsin's engine builder said all those things about the Piper cams is testament to the work that Piper have done, especially when you consider that he's no stranger to the HKS cams (as he builds all of Fensport's engines).

[Matty_GTS]

Whats the duration of the standard Toyota cams?

MR2Mania suggested to me staggering the profiles like toyota do, would like to see what they have staggered the amounts by.

Ta

[MR2Mania]

Whats the duration of the standard Toyota cams?

As described above, the duration quoted isn't necessarily comparable to another cam, because ideally you want to be comparing like for like, ie duration at 1mm lift, which is not always possible.

I've just been searching for that great thread on MR2OC but can't find it! That listed all the lifts for the various cams they've tested, including stock. I don't even have my HyperRevs mag here to see what the stock cam durations are, but I do remember that peak lift on inlet for Rev3 is 8.7mm on the intake, and 8.2mm on exhaust. The Rev1/2 have 8.2mm lift on both sides, IIRC.

MR2Mania suggested to me staggering the profiles like toyota do, would like to see what they have staggered the amounts by.

I said it was a possibility, mate. However, looking at what you said for your future mods, you may just opt to go for 264s for both sides.

[Ed]

Whats the duration of the standard Toyota cams?

MR2Mania suggested to me staggering the profiles like toyota do, would like to see what they have staggered the amounts by.

Ta

You may want to read <A href="http://www.mr2oc.com/showthread.php?t=1 ... comparison" target=_blank>This Post</A>.

Although the testing was done on a stroked motor it shows that 264 on both sides is the best combination.

HTH Ed

[MR2Mania]

You may want to read <A href="http://www.mr2oc.com/showthread.php?t=1 ... comparison" target=_blank>This Post</A>.

Although the testing was done on a stroked motor it shows that 264 on both sides is the best combination.

HTH Ed

Ed, those were HKS cams. Also, not only does the capacity make a difference, but also the turbo. I'd say that you should be looking at matching the cams to the turbo. But when you're also trying to make it nice and smooth for street driving too, it's best not to go too crazy on duration, otherwise idle and off boost get very lumpy.

264s all round is a good street compromise. Jonno's got HKS 264s (the Pipers weren't available at the time of his build) and the engine runs just as smoothly as mine at idle and low down.

[cantfindausername]

Is this what you're after?

Stock 2nd gen motor: (intake and exhaust)

Advertised duration 236 degrees

Duration @ 0.010" lift: 260.0 degrees
Duration @ 0.020" lift: 211.0 degrees
Duration @ 0.050" lift: 160.5 degrees

Max Lift: 8.52mm (0.335")

Stock 3rd gen motor INTAKE:

Advertised duration 240 degrees

4 degrees more duration, .5mm more lift than the 2nd gen

Stock 3rd gen motor EXHAUST:

Advertised duration 236 degrees

Duration @ 0.010" lift: 260.0 degrees
Duration @ 0.020" lift: 211.0 degrees
Duration @ 0.050" lift: 160.5 degrees

Max Lift: 8.52mm (0.335")

HKS 256 cams:

Duration @ 1mm lift: 216 degrees

Max lift: 9.0

HKS 264 cams:

Duration @ 1mm lift: 224 degrees

Max lift: 9.2mm

The HKS 2nd gen "low lift" 264 cams use a lobe centerline of 110deg ATDC intake, and 103 deg BTDC exhaust.

HKS 272 cams:

Duration @ 1mm lift: 232 degrees

Max lift: 9.4mm

The HKS 2nd gen "low lift" 272 cams use a lobe centerline of 110deg ATDC intake, and 108 deg BTDC exhaust.

HKS "high lift" 256 cams:

Duration @ 1mm lift: 216 degrees

Max lift: 9.5mm intake, 9.2mm exhaust

HKS "high lift" 264 cams:

Duration @ 1mm lift: 224 degrees

Max lift: 10.0mm intake, 9.7mm exhaust

HKS "high lift" 272 cams:

Duration @ 1mm lift: 232 degrees

Max lift: 10.4mm intake, 10.2mm exhaust

The HKS 3rd gen 272 "high lift" cams use a lobe centerline of 111deg ATDC intake, and 116 deg BTDC exhaust.

TODA cams:

NOTE: These are advertised duration only, usually assumed to be 0.020" or .5mm.

Duration Max Lift(mm)
256_____8.5
256_____9.0
264_____8.5
264_____9.0
264_____10.3
272_____8.5
272_____9.0
272_____10.3
280_____10.3
288_____8.5
288_____9.0
288_____10.0
288_____10.5
304_____8.5
304_____9.0
304_____10.5
310_____10.5
320_____10.8

JUN cams:

Part # 1004M-T001 (intake) 1004M-T101 (exhaust):
256° duration 9.0mm lift

Part # 1004M-T002 (intake) 1004M-T102 (exhaust):
264° duration 9.0mm lift

Part # 1004M-T003 (intake) 1004M-T103 (exhaust):
272° duration 9.3mm lift

[Ed]

You may want to read <A href="http://www.mr2oc.com/showthread.php?t=1 ... comparison" target=_blank>This Post</A>.

Although the testing was done on a stroked motor it shows that 264 on both sides is the best combination.

HTH Ed

Ed, those were HKS cams. Also, not only does the capacity make a difference, but also the turbo. I'd say that you should be looking at matching the cams to the turbo. But when you're also trying to make it nice and smooth for street driving too, it's best not to go too crazy on duration, otherwise idle and off boost get very lumpy.

264s all round is a good street compromise. Jonno's got HKS 264s (the Pipers weren't available at the time of his build) and the engine runs just as smoothly as mine at idle and low down.

Hi Dino, I'm pretty much convinced that I'll be speaking to you about a set of the Pipers when I come to getting cams.

My only question is with the Pipers is when they were doing all the dyno and flow testing did they test beyond the stock rev limit. I will be revving to 8500 RPM so it would be useful to know how the cope at high RPM.

Cheers Ed

[MR2Mania]

That's the one, mate!! You don't happen to have a link to the original thread though, do you?

Anyway, that shows that the "advertised" durations for Rev1/2 are 236deg/236deg in/ex, and for the Rev3 they are 240deg/236deg in/ex.

Just so that people can understand that fully, 0.010" (or "10 thou") is the measurement of lift in inches, and this corresponds to 0.25mm, so 1mm is 0.040" (or 40 thou).

I *think* that they've got the lift wrong for the Rev1/2 cams (I'm pretty sure it was 8.2mm, but I could be wrong).

[cantfindausername]

Sorry dude I aint got the original post. I'll go look about though see if I can find it again.

[cantfindausername]

http://www.mr2oc.com/showthread.php?t=818

I'm so goood... Go Ant.. Its ya burfday... <does a little dance>

its not my birthday btw

[MR2Mania]

My only question is with the Pipers is when they were doing all the dyno and flow testing did they test beyond the stock rev limit. I will be revving to 8500 RPM so it would be useful to know how the cope at high RPM.

Ed, this is how we did things...

I obtained flow figures for my stock Rev3 head at a set pressure and different valve lifts before and after the head work I had done. This info could tell Piper what gains there were to be had, and what they needed to concentrate on (ie lift, duration, ramp rate)

We also looked at the valve spring rates, lengths, and preloads to determine how much load was being put on the valvetrain.

Piper then examined what sets of stock and HKS cams do in terms of duration, lift and ramp rates. They then worked on improving overall flow based on the head flow figures I gave them.

So, they weren't based on dyno figures which introduce other variables that can't be controlled (eg boost control issues, mapping issues, turbo issues, etc). They simply looked at the flow side of things, and how best to fill the cylinder.

That's why there are no conclusive dyno figures yet, although looking at how well AndyF's engine is working even at only 1.2bar shows that the cams are working very well. ISTR that Andy was running HKS 272s before this, too, which he hand to change when they got trashed.

Anyway, this is the exact same procedure that my mate used when helping develop the profiles for the Evo engine, and the results have been SO good in comparison to HKS offerings (proven on loads of engines now, and on dynos) that his Piper cams have pretty much become the defacto standard for Evo tuning.

I should point out that it's *my* fault that we haven't dyno proved the 3SGTE cams, since I still wanted to do testing for the my chargecooler development and didn't want to introduce the cams into it as this would have given results that then couldn't be directly compared to others unless they too had cams.

[MR2Mania]

http://www.mr2oc.com/showthread.php?t=818

I'm so goood... Go Ant.. Its ya burfday... <does a little dance>

its not my birthday btw

LOL! Is that the "In da Pub" version, done my 50 pence?

[cantfindausername]

Yup.. .and pull up in ma Nova!

[ENSMR2]

Dino how much for a set of 2x 264's please.

After speaking to chrisK at length the other day on the phone, he also says sticking to 3SGTE specific cams is wise. However there aren't many out there. Only piper I think? He also recommends a staggered set up of 272in 264 out for any application.

Anyone know the price of getting a custom set of cams grinded? Dino?

[MR2Mania]

Dino how much for a set of 2x 264's please.

Normally, they're £450+VAT, delivered, but I can do them for £465 all in.

After speaking to chrisK at length the other day on the phone, he also says sticking to 3SGTE specific cams is wise. However there aren't many out there. Only piper I think? He also recommends a staggered set up of 272in 264 out for any application.

ChrisK knows about the Pipers, as we've spoken about them, and I even invited him to work with Piper to develop a set of cams that he can have exclusively in the US, but at the time he was busy with other things. I should really check with him to see what his current position is on this.

Anyone know the price of getting a custom set of cams grinded? Dino?

Piper can do custom profiles (don't know the price though) but you need to know what you're asking for. Again, ChrisK is the only other man I know other than Piper that can work out their own profiles. I doubt he'll give out any further info though unless he develops a set with Piper himself.

[ENSMR2]

Normally, they're £450+VAT, delivered, but I can do them for £465 all in.

Ah, nice price. I may require a set soon.

Piper can do custom profiles (don't know the price though) but you need to know what you're asking for.

Do you have the number that I would need to call?