TheSamba.com :: View topic - New CB camshaft: 2228 any one tried it yet?

Mon Jan 28, 2013 3:58 am

I think this is a new one, comes with 112º lobe centers instead of the usual 107 from Eagle

Adv. Duration 274°
Dur. @ .050" 224°
Lift @ cam .357"
Lift w/1.1:1 Rocker Arms .393

I wonder how it compares to the cheater cam?

Mon Jan 28, 2013 8:27 am

It's almost identical to the 2280 cheater specs other than lobe centers. Only a few thou off. The .050 numbers are the same.

Mon Jan 28, 2013 10:45 am

so what does cb say about it?? is the intake lobes moved?ex lobes moved? or both moved?

Tue Jan 29, 2013 8:16 am

This is all they say :roll:

Every Eagle Racing Camshaft is designed in our own shop from a new high quality Proferal Cast Iron Billet. Our profiles provide horsepower and revving ability while running moderate spring pressures. Eagle Racing Camshafts: a dyno-proven, quality product. Eagle Cam Gears are sold separately. Ground on a 112° Lobe Center.

Adv. Duration 274°
Dur. @ .050" 224°
Lift @ cam .357"
Lift w/1.1:1 Rocker Arms .393"

http://www.cbperformance.com/ProductDetails.asp?ProductCode=2228

on paper it does look really similar to the cheater cam but on wider centers, in theory I guess it should have a flatter, larger torque curve, but I'd like to hear some real world experience!

Tue Jan 29, 2013 9:21 am

I don't have any direct experience running the Cheater cam however FWIW last year I called one of CB's tech people to ask about changing the lobe center for use as a fuel mileage cam, to see if there would be any benefits by going to say, 110LC. The tech told me this, he didn't think there would be much difference or improvement in fuel mileage however he did make the comment that CB had tried the Cheater cam on increased LC on their dyno and the engine ran hot. No matter what they did it ran hot. They swapped a normal 107LC Cheater cam back in and temps returned to normal. Hmmm....

Tue Jan 29, 2013 10:12 am

I consider myself fairly knowledgable about cams, but I don't really understand what/how changing the lobe center does to a motor's running characteristics. I do know that- usually cams with 112' lobe centers are favored by the turbo guys and people building naturally aspirated motors will use cams with 105-108' lobe centers (I believe that most n/a cams are ground on 107 or 108' lobe centers) for best balance of high/low power.
Good info, Darth.

A slight thread hijack- how does changing lobe center from 108 to 105 degrees affect a dual carbed motor? would it have more or less effect(or is it the same) if there was more duration/higher powerband?

Tue Jan 29, 2013 12:01 pm

Going to 112 LC does stuff to the incoming mix. I wouldnt be surprised that most the hot running issues disappear when going to 112 LC That would put the intake dur. @ 0,050 right back to where it is on a stock cam at 0,040".

That would result in an engine that will rev somewhat higher than a stock, but will actually pull less torque than the 2280 (which is one of the reasons that I like the 2280)

Very roughly explained, the engine will use less fuel because it can work less in the driving rpm. And there is also almost zero valve overlap on the BTDC side. If you need power you will have to rev it. Then it sort of will come back to ya.
But taken the torque characteristics of that cam, it will most likely not be exactly lazy down low, it´ll just pull less than the 2280 with the advantage of a slightly improoved fuel efficiency. How much is hard to say, - maybe,,,,,- 6-7%

Pat. Please correct me if I´m wrong.

T

Tue Jan 29, 2013 12:23 pm

Hmm. Sometimes one should look more into stuff before answering.

I just ran the cam through a couple of known stock and stockish engines. It seems that compared to the 2280 it only looses marginally torque below 3000 (2 lbs @ 2000, 1 lbs @ 2500 and equals at 3000, - in my set up anyway) but gains 3 hp @ 5000 rpm. That was expected.

Interesting.

T

Tue Jan 29, 2013 12:31 pm

I assume that was a simulation. I didnt think it would loose any, but possiably gain a bit, but more likely more the band width & location.
I wish they would have a good discription of the cam other than just the basic specs, it would make it a lot easyer for the regular guy pick a cam. there are many cams that have the same basic numbers but react totaly diffrent.
I wish I could get to my hyd roller motor & finish it to see just what I have, but I dont see time getting on my side for a while.

Tue Jan 29, 2013 12:57 pm

mark tucker wrote: I assume that was a simulation. I didnt think it would loose any, but possiably gain a bit, but more likely more the band width & location.
I wish they would have a good discription of the cam other than just the basic specs, it would make it a lot easyer for the regular guy pick a cam. there are many cams that have the same basic numbers but react totaly diffrent.

Yes it was a simulation. You are so correct wrt descriptions. CB actually have a number of cams that kicks butt, but they live in the shades, because people dont know them.

T

Tue Jan 29, 2013 1:00 pm

ALB wrote: I consider myself fairly knowledgable about cams, but I don't really understand what/how changing the lobe center does to a motor's running characteristics. I do know that- usually cams with 112' lobe centers are favored by the turbo guys and people building naturally aspirated motors will use cams with 105-108' lobe centers (I believe that most n/a cams are ground on 107 or 108' lobe centers) for best balance of high/low power.
Good info, Darth.

A slight thread hijack- how does changing lobe center from 108 to 105 degrees affect a dual carbed motor? would it have more or less effect(or is it the same) if there was more duration/higher powerband?

The key thing to understand is, when the intake valve closes has more effect on the power band than any of the four timing events. The longer the intake stays open the more top end it will have from the ram effect.

Wider LC's and retarding the cam timing will both keep the intake open longer and will add top end. The other three events will also affect the engine but not to the same degree. Dan

From webcams site.

LOBE SEPARATION ANGLE

Above 114 Deg. = Extremely Wide
114-112 Deg. = Wide
112-110 Deg. = Moderately Wide
110-108 Deg. = Moderate
108-106 Deg. = Moderately Tight
106-104 Deg. = Tight
Below 104 Deg. = Extremely Tight

VARYING LOBE SEPARATION ANGLE

Tighten
Moves Torque to Lower RPM
Increases Maximum Torque
Narrow Powerband
Builds Higher Cylinder Pressure
Increase Chance of Engine Knock
Increase Cranking Compression
Increase Effective Compression
Idle Vacuum is Reduced
Idle Quality Suffers
Open Valve-Overlap Increases
Closed Valve-Overlap Increases
Natural EGR Effect Increases
Decreases Piston-to-Valve Clearance

Widen
Raise Torque to Higher RPM
Reduces Maximum Torque
Broadens Power Band
Reduce Maximum Cylinder Pressure
Decrease Chance of Engine Knock
Decrease Cranking Compression
Decrease Effective Compression
Idle Vacuum is Increased
Idle Quality Improves
Open Valve-Overlap Decreases
Closed Valve-Overlap Decreases
Natural EGR Effect is Reduced
Increases Piston-to-Valve Clearance

Tue Jan 29, 2013 2:17 pm

That's a good start. Thanks Dan.

Tue Jan 29, 2013 2:42 pm

Would be a good cam for a 1600 turbo. :twisted:

Wed Jan 30, 2013 4:57 am

alstrup what induction(s) were you using for the simulation?

thanks for your input! :D

Wed Jan 30, 2013 12:06 pm

[quote="Dan Ruddock"] ALB wrote: I consider myself fairly knowledgable about cams, but I don't really understand what/how changing the lobe center does to a motor's running characteristics. I do know that- usually cams with 112' lobe centers are favored by the turbo guys and people building naturally aspirated motors will use cams with 105-108' lobe centers (I believe that most n/a cams are ground on 107 or 108' lobe centers) for best balance of high/low power.
Good info, Darth.

A slight thread hijack- how does changing lobe center from 108 to 105 degrees affect a dual carbed motor? would it have more or less effect(or is it the same) if there was more duration/higher powerband?

The key thing to understand is, when the intake valve closes has more effect on the power band than any of the four timing events. The longer the intake stays open the more top end it will have from the ram effect.

Wider LC's and retarding the cam timing will both keep the intake open longer and will add top end. The other three events will also affect the engine but not to the same degree. Dan

From webcams site.

LOBE SEPARATION ANGLE

Above 114 Deg. = Extremely Wide
114-112 Deg. = Wide
112-110 Deg. = Moderately Wide
110-108 Deg. = Moderate
108-106 Deg. = Moderately Tight
106-104 Deg. = Tight
Below 104 Deg. = Extremely Tight

VARYING LOBE SEPARATION ANGLE

Tighten
Moves Torque to Lower RPM
Increases Maximum Torque
Narrow Powerband
Builds Higher Cylinder Pressure
Increase Chance of Engine Knock
Increase Cranking Compression
Increase Effective Compression
Idle Vacuum is Reduced
Idle Quality Suffers
Open Valve-Overlap Increases
Closed Valve-Overlap Increases
Natural EGR Effect Increases
Decreases Piston-to-Valve Clearance

Widen
Raise Torque to Higher RPM
Reduces Maximum Torque
Broadens Power Band
Reduce Maximum Cylinder Pressure
Decrease Chance of Engine Knock
Decrease Cranking Compression
Decrease Effective Compression
Idle Vacuum is Increased
Idle Quality Improves
Open Valve-Overlap Decreases
Closed Valve-Overlap Decreases
Natural EGR Effect is Reduced

Some of that web cam info seems counter-intuitive.
With lobe a lobe center like 105* it would seem dynamic compression would be bled off until higher RPM's are reached, then the effects of valve overlap in conjunction a properly tuned exhaust and intake would help trap more volume. One thing I would add to the Web-Cam list is the narrower the centers are the louder the carbs. Can someone set me straight

Wed Jan 30, 2013 3:18 pm

A lower LSA causes the intake valve to close earlier, raising compression.

A higher LSA closes the intake later and opens the exhaust earlier, so you will see some similar effects as having a cam with longer duration. But obviously not exactly the same. For example, the decreased overlap also makes it seem more like a lower duration cam at low rpm/idle.

Increasing LSA rotates the blue intake circle clockwise and the red exhaust counterclockwise:

Apologies that they didn't draw the exhaust circle and lobe better aligned here. Keep in mind that in a cam timing diagram like this, the angle between lobe tips (labeld Lobe Center) is actually double the LSA because you are converting from a 360 degree physical object into a 720 degree diagram. So in this example, the cam's LSA of 102 degrees makes the center points of the red and blue arcs 204 degrees apart.

Wed Jan 30, 2013 4:55 pm

hey that will never run the valves are never closed at the same time so it cant get no compression, wont it bend a valve? or is this for a 3stroke motor?? :roll: had ya going for a sec .

Fri Feb 01, 2013 4:47 am

Slow 1200 wrote: alstrup what induction(s) were you using for the simulation?

thanks for your input! :D

I used a stock 34 mm Pict3 and one with a 28 mm venturi.

T

Fri Mar 29, 2013 6:29 am

I'm going to try it. My 1745 is acting up, had some probs my last outing on autobahn.... valve train related probs.

I'm currently running an FK-65, and have always been unhappy with how hard the torque comes on, and a hesitation in transition from idle. It's lazy at off-idle, then comes on strong, just as the clutch comes out, not a pleasant driving experience in stop-and-go traffic. I've fiddled with timing and idle jets, etc.. I really think the problem is related to dilution through too much overlap.

This cam (2228) should help. I will be sacrificing on top, as the valve simply will no longer lift high and long enough for me to still get the filling I'm now getting at 5000+ rpm, but the dilution of the incoming mix should be reduced at low rpm.

the IVC on the 2228 is 48° ABDC, on the FK-65 it's 46° ABDC, so I'm either going to leave compression as it is, at 8.75:1, or do a light flycut to clean up the surface and bring C/R to 9:1.

I'm using 40 Kads, will switch to 34 dual Solexes, I need the chokes. I will step up to a 28mm venturi, but I doubt the flow will match the Kads.

It's the age of downsizing...

Hope to re-use the rest, bottom end, etc..

If I didn't allready have the (lightened) flywheel and clutch and crank balanced, I would switch to heavy 180 mm flywheel..next project!

Any thoughts are welcome, and I will try to post results.

Fri Mar 29, 2013 6:32 am

Oh, and though the exhaust duration is 224°, the intake is 233°. It's a dual-pattern cam.... neat!