Darth_V8r

iTrader: (4)

So, what's new in camshaft lobe theory and testing?

KCS

iTrader: (20)

Looks like Comp has lobes for 9000 RPM hydraulic rollers. EPM/EPX.

bortous

Well if you want to talk generally, TSP, Cam Motion and others are all heading in the same direction with lobe design,
They are focusing on smooth lobes that run quiet and don't destroy your valvetrain.
There used to be a lot of variance years ago in the XE-R era.
I remember EPS lobes and these guys are probably the ones that began the smooth lobe trend.
I doubt there would be much if any power difference between them anymore if you had the exact specs and tested them back to back.
The more aggressive lobes which are in the catalogues probably make a bit more power and give you faster acceleration but your valve train takes a beating in return.
I believe the next evolution is ironing out all the cons of solid rollers and making them almost maintenance free like the hydraulic rollers.
I think comp cams have already started heading in this direction.

bortous

I saw that too.
Smokey is always rambling on about high rpm's,
He should give these lobes a go.
9000rpm though is going to require titanium rods light valves a billet crank, intake, and a solid foundation for the engine to live.

Darth_V8r

iTrader: (4)

Hopefully, this survives the external link policy, as they are selling nothing. A good BASIC description of the design parameters and what goes into lobe design, and some of the maths...https://www.tildentechnologies.com/Cams/CamDesign.html

If it does not survive the policy, I understand, but it is focused on triumph platform, so non-competitive.

Alot of info is probably well protected.


Comp seems to be really moving and shaking. TBH, I need to get over the one bad cam I got four years ago.

KCS

iTrader: (20)

You can do 9000 RPM and higher on steel rods, it’s more common than you think. A fully counterweighted crank would be a must for it to live though. I would ditch the OEM style pump for a dry sump or an external pump wet sump at the very least. That would be a very interesting build for someone with deep pockets.

KCS

iTrader: (20)

Agreed. If you’re not following Billy G on Facebook, you’re missing out. I need to get over the broken Comp spring from a few years ago too. People are having success with the conical springs and I’m a little jealous.

JakeFusion

iTrader: (7)

Mmm fully CCW crank.

I think solid roller is still the best way forward. The LLR from Cam Motion is a good street compromise.

Comp has some mild street solid rollers that work well too. Especially with the square port heads that flow a ton at higher lifts, being able to get there in a stable fashion is going to pick up power.

The only downside is cost of the rockers and possibly having to check lash. But I would just check lash at every oil change.

Hodgdon Extreme

Regarding 9000rpm:

When I worked on the dyno, we tested a lot of SB2.2 and R07 cup car engines. This was back in 2007-2010, and routinely took them to 9500. We had a "spintron" test cell - wasn't spintron brand, but it was a motoring-only cell with no fuel or fire.

For the spintron, we had special engine blocks with windows in the cylinder so that we could set up a laser looking at the valves. Thus, we could measure/analyze valvetrain kinematics, in real time, as a function of crank angle. These "engine bucks" had no rods, no pistons and obviously NO airflow. Crank was only there to spin the cam.

Anyway, to come to the point: Whether an actual engine was making smoke on the dyno, or simply being spun by the spintron - there was always a sound change at about 8200rpm. Up past 8200, you COULD NOT tell the difference between the engine that was actually running and producing 800hp, vs the engine that was just being spun. Keep in mind - the spin buck was not sucking, squishing, banging or blowing.

ALL the sound you hear come out of a cup car engine up past ~8200 is VALVETRAIN noise...

And by the way, the cup cars all use steel rods.

bortous

Excellent

spanks13

iTrader: (5)

Listening to Billy G's facebook videos of the spintron running are absolutely unreal at 9000+ rpm. 100% agreement with Hodgdon. They sound like freaking prostock motors and they aren't even firing.

Billy is so unbelievably generous with his knowledge. He just loves this stuff.

Jenson

iTrader: (32)

EPS was proprietary design, ground by comp, then comp started selling them as there own lobe, off he went to cam motion. Kip is very good to deal with, the personal touch to each custom ground cam is amazing.

Smooth grinds have been around forever, they are just being adapted/re-designed to modern head flow characteristics and usage.

TSP has really stepped into the game hard with their new to them machines back in '16 too. Most people dont talk about their stuff as being their own designs, but from what Ive seen and been told just about everything coming out of there now is no longer a comp lobe. Did an F35 in a '12 camaro recently, ran fantastic, super quiet, easy to tune, and obviously sounded amazing.

bortous

Good to know.
I wonder what camshaft tech will be like in the next 10 years?
I wonder if they will be able to make real aggressive camshaft drive like stock.

Darth_V8r

iTrader: (4)

It will probably look like a bunch of off-centered eggs on a steel shaft with some perfect circles mixed for bearing journals.

There is all kinds of cool stuff out there for lobe shape but I still maintain valve control is king. I think you see gentler lobes make more power in many applications simply due to improved valve control.

Any you see people who do a great job setting up the valves, and real shitty, out of date lobes do just fine.

I am a big believe in what cam motion brought to our hobby. Kip rescued me a couple of times on weird **** going on so I am rather biased

Jenson

iTrader: (32)

The way its going, in 10 years, there wont be any V8 cars. Its really sad when its impossible to find a manual V8 rwd sedan and 90% of the sports cars at the dealer are autotragic.

Those big aggressive lobes need a lot of spring to control them, which in turn is pumping loss, which in turn is lost power. So you either have to need that big aggressive lobe (per class rules or some sort of high rpm monster) or have jesel J3's or something along those lines to offset some of that MOI/pumping loss. Which points back to solid rollers, which most people just dont want to deal with on the street. Which points back to Kip's LLSR which are the best of both worlds IMO. I just wish I could get more customers on board with them

G Atsma

That's because most people are after the magic 0-60 time, and face it, the contemporary autotrannies will beat a stick every time.

bortous

Automatics are the way these days.
Manuals are getting phased out because the automatics are more fuel efficient, quicker and they put less stress on the driveline when applying power.
I have a stick car a 2005 Honda Civic sedan as a daily and I get sick of the gears sometimes.
But it does give you a sense of control

Hodgdon Extreme

Don't mean to nit-pick, but overcoming higher valvespring force (hate using the term "pressure" because pressure is force per unit area) is not a pumping loss. It's actually not really a loss at all, because compressing the spring puts energy in the bank - which you get back out once you're on the closing ramp and the spring begins putting the energy back into the rocker, which returns energy into the cam, etc.

As a parallel - that is how the displacement on demand systems work... They de-activate the valves and shut down the injector for a given cylinder immediately following the intake cycle. Thus, it takes work FROM the crank to squeeze that air during compression, but it puts that work back into the crank as the "air spring" pushes the piston back down the cylinder during what would have been the power stroke. There are some heat losses on account of the air temperature increase of compression, but over 95% of the work is recovered.

Hodgdon Extreme

Blasphemy!!

bortous

Lol
I know it's hard to let go