Piper Camshafts

[celek]

Originally Posted by dallenj

It looked like they made a good power difference. They probably didn't have anyone buy them.

From what I understand there is a Cup Series in Europe that exclusively uses Piper so they do have a captive audience buying lots of cams

[Tim Radley]

Originally Posted by celek

From what I understand there is a Cup Series in Europe that exclusively uses Piper so they do have a captive audience buying lots of cams

They have sold over 50 sets and also are doing the cams for the new Subaru in British Touring Cars (BTCC) this year.

[celek]

Just got this email today...
Website not updated but looks like ready to ramp back up

[Fonzi]

I had the first cams from them in the states. My car just got finished 2 weeks ago from 2.5 years of down time. I cant really say how good they from stock because i completely built my motor and changed everything. I am boosted, idle is great! I dyno'd 430hp and its lots of fun! Still have more power to go too.

[sw20kosh]

Where are the NA results with cams? I am surprised no one has experimented...

[Blokatos]

Originally Posted by Tim Radley

Depends on the cam profile. A 13mm lift cam may have more piston to valve clearance than an 11mm lift cam. Depends on duration and ramp rate. Lift at TDC is a good indicator but not the gospel. Closest point of contact is circa 10 degrees off TDC on most engines.

Well, this is not as accurate as it should be. A 13 mm cam will always bring the valve closer to the piston, all else being equal. Ramp rates and duration play a role to the relation the valve has with its seat, not with the piston.

If you are referring to the valve to piston clearance at TDC, then this is a whole different story and it has to do with the actual valve timing ground into the cam lobes or what is dialed in with the cam gears...

[Tim Radley]

Originally Posted by Blokatos

Well, this is not as accurate as it should be. A 13 mm cam will always bring the valve closer to the piston, all else being equal. Ramp rates and duration play a role to the relation the valve has with its seat, not with the piston.

Sorry but that is just not the case. Piston to valve clearance is tightest at lower lift not higher lift. At max valve lift the piston is more than half way down the bore. A 13mm lift with 240 duration will likely have a lot more piston to valve clearance than an 11mm lift with 280 duration. Adding 1mm of lift to a cam profile doesn't mean you need 1mm deeper pockets cutting in the pistons.

[Blokatos]

Originally Posted by Tim Radley

Piston to valve clearance is tightest at lower lift not higher lift.

Yep, that's why I said I wrote all else being equal.

Originally Posted by Tim Radley

Adding 1mm of lift to a cam profile doesn't mean you need 1mm deeper pockets cutting in the pistons.

I didn't say that, that is your assumption/speculation.

Originally Posted by Tim Radley

A 13mm lift with 240 duration will likely have a lot more piston to valve clearance than an 11mm lift with 280 duration.

That is an opinion and I can respect that. However, a 280 duration 11 mm lobe may have more clearance than the 13mm - 240 degrees one depending on how the ramps are ground.

And to widen the discussion, the camshaft choice for the FA20 is not an easy topic.
"Hot" cams today are not what they used to be and that is the main reason we don't see many of them on the market.
It is quite important for every enthusiast to understand that cams are merely valve timing tools. In the pre-variable valve timing era, cams could alter the valve timing events to suit the needs of the driver.
This doesn't apply directly today since there solenoids that already alter the timing event based on input from various sensors across the car.

I cannot stress this enough, changing cams on the FA20 is not the same as it was 20 years ago on a simple DOHC multi-valve performance engine.

Regarding valve lift, increasing it will allow the engine to breathe better at the upper part of the rev range or perhaps beyond the stock rev limit. In most engines, lift is not a bottle neck for the 19/20's of the stock rev range and increasing it may hurt air speed at mid/low range. Careful consideration, planning and reading is required, engine tuning is not easy but its a lot of fun.

Cheers

[Tim Radley]

Originally Posted by Blokatos

That is an opinion and I can respect that. However, a 280 duration 11 mm lobe may have more clearance than the 13mm - 240 degrees one depending on how the ramps are ground.

But how can the ramp rates have that much affect on the low lift of symmetrical (or very close to symmetrical) profiles when there is a 40 degree increase in that example? Assuming symmetrical then you will be opening 20 degrees earlier and closing 20 degrees later for the same lobe centre. Therefore the 280 cam has a far tighter clearance than the 240 regardless of peak lift at the critical point.
Some cam profiles run very fast opening inlet and fast closing exhaust to minimise overlap whilst having good area but those kind of profiles are found on finger followers in high end race engines, not something like an FA20.

[Blokatos]

It is obvious that when the valve is closed (240 deg lobe example) it has more clearance than the partially open example of the 280 deg lobe.
You have to remember though that the 240 deg cam has much less time (degrees) to open a lot more the valve (2 mm) which makes it highly probable that it will have much more aggressive ramps.
If we make a rough calculation, one opens 0.039 mm/deg and the other 0.054 mm/deg of average opening (and closing) rates. Its rather obvious which may have more aggressive lobes...
Increase lift only if your engines needs it. Besides clearance, higher lift raises the risk of valve float as the lobe it is actually "shooting" the valve towards the combustion chamber and piston with the more aggressive ramps. To offset that, you will need stiffer springs which will robbing you power through parasitic losses at all engines speeds below the max power rpm.
I am still assuming that we are discussing a street legal sports car that it will see daily driving duty as well. Pure race engines is a different story...

[Kris86]

Originally Posted by Fonzi

I had the first cams from them in the states. My car just got finished 2 weeks ago from 2.5 years of down time. I cant really say how good they from stock because i completely built my motor and changed everything. I am boosted, idle is great! I dyno'd 430hp and its lots of fun! Still have more power to go too.

come on mannnn, you know we wanna hear that "cam idle"

[bem75]

Any new feedback on these cams? I am interested from a pure race engine standpoint. Jackson Supercharger, 9 psi, built engine. Forged pistons, Carillo rods, GSC valve springs, Motec M150. I just don't know enough about camshafts in this engine to decide what will work best. The rules for my class allow 0.600" lift.

[CounterSpace Garage]

Originally Posted by bem75

Any new feedback on these cams? I am interested from a pure race engine standpoint. Jackson Supercharger, 9 psi, built engine. Forged pistons, Carillo rods, GSC valve springs, Motec M150. I just don't know enough about camshafts in this engine to decide what will work best. The rules for my class allow 0.600" lift.

That's quite a bit of lift. We have a couple sets of camshafts coming in for measurement only on a few engine projects. We have Ferrea valvetrain components in these engines so everything has to be taken into consideration.

[CounterSpace Garage]

Got a set of Piper Cams installed.