I buried this in another large thread and wanted to break it off into it's own thread so it's easier to find. I figured those of you who have tested other popular drop in cams in current model softail 96 / 103 twin cams can post your data here to help others.

These are my tested results of the stock 2013 Breakout 103" motor with stock cams > then 57h cams > then 48h cams. The 48's run the strongest across the board as drop ins to my stock unmodified motor w/ 9.53:1 static cr. just wanted to share the tech data here, and my summary findings, in case someone finds it interesting / helpful.

Engine tested April 26 2016 prior to cam upgrades:

• Static Compression Ratio @ 9.53:1 (HD specs call for 9.6:1 stock but there is always some mfr variance) Static compression ratio remains the same regardless of cams installed
• >> Stock cams (IVC @30): 187 F / 188 R CCP, 9.11:1 Corrected (Dynamic) Compression Ratio
• >> 57H cams (IVC @38): 181 F / 182 R CCP, 8.68:1 Corrected (Dynamic) Compression Ratio
• >> 48H cams (IVC @29): 188 F / 189 R CCP, 9.14:1 Corrected (Dynamic) Compression Ratio
• * CCP's based on altitude @ sea level

Andrews 57h cam specs - optimal at 9.8:1 - 10:1 static cr, results in 9.2:1 - 9.3:1 dynamic cr:
I: 18/38 236 .560
E: 46/14 240 .560
Good 3000-6800rpm

Andrews 48h cam specs - optimal at 9.5:1 - 9.7:1 static cr, results in 9.1:1 - 9.3:1 dynamic cr:
I: 13/29 222 .548
E: 43/15 238 .548
Good 2000-5000 rpm

HD Stock cam specs for 2007-2012 Injected HD air cooled twin cam V Twin:
I: 12/30 198 .484
E: -38/04 222 .484

ONE OF THE BEST reads you'll find on learning about correct cam choice for your current motor's build and compression:
http://www.crankshaftcoalition.com/w..._compatibility

if you study the info closely and look at the charts, you'll see why the 57h / 37h cams will benefit from higher compression than stock vs the 48h being optimal with less compression. Some of this has to do with looking at the duration numbers. You'll see that the 57h cams' duration spec is optimal at higher compression like 10.5:1 and 3000-6800rpm range. whereas the 48h duration spec is optimal at about 10:1 and 2000-5000rpm

However- we cannot run 10.5:1 with the 57h or 37h cams, or 10:1 with the 48h due to the early close intake event. This is where it is a bit tricky because we have to remember this is a HD twin cam and we cannot really operate it on pump gas at much over 9.4:1 dynamic compression. Optimally we should stay around 9.1-9.3. (Good engine builders and tuners can run street motors all day long at 9.5:1 DCR on pump gas without excessive heat or ping issues, but this is where experience and expertise pays off).

So working on the compression a bit to keep us in a safe range of operation, we see that the 57h (and 37h) would be optimal in the twin cam with a static compression of 10:1. that gives us a dynamic comp of about 9.26:1 - awesome. the bike will pull good off the line due to the good operating compression and will "come on the cam" at 3k rpm, pulling to 6800.

For the 48h cams- we can really see why this cam works so well in the 96 and 103 with a stock compression range of about 9.5-9.6:1. This cam was designed for it. With a stock compression of 9.6:1 we get back a static comp of 9.21:1 - excellent. the bike will pull hard off the line and come on the cam at 2000rpm, pulling hard until 5000rpm (per the duration numbers). IMO this is a top choice for a street drop in cam on 96 or 103 unmodified motor and from what I can see and have felt, better by far than the 57h.

The caveat being, if you throw some compression at the 57h (or 37h) it will be a better performer and pull a bit harder mid to upper rpm than the 48h. but we're splitting hairs and it's not going to be a big diff on a stock motor with stock heads. Actually the stock heads negate any flow benefit of the higher lift cams.

There are other good cam choices out there from Woods, S&S, SE etc, this was really intended to just get some info out there on two popular "drop in" cam choices and document my own experience / results with them.

My results say that in my stock 103" motor with 9.53:1 static cr, the 48h is a much more solid performer as an all around street performance / daily rider cam than the 57h. The DCR and CCP numbers above at top of my post support this. Some of you may have different results. these are just mine.

 

I find that ratios are a good starting point, but cranking pressure is where the real data is. I am sure plenty will disagree with me though.

 

^ Prot- You are correct but the DCR and CCP are the same thing just presented as different values of measurement. See above the CCP's are listed for each set of cams. The only physical CCP and DCR measurement came from my compression testing of the stock cams in the motor. The other cams' CCP are based on the IVC close event and estimated change in CCP / DCR.

If you use an online engine builder tool like the one at Big Boyz website (or others), the DCR and CCP are always presented together as a result of cam selection and IVC events. Whichever measurement you choose to work with is fine as either will tell the exact same story, but there is nothing to disagree on since it's the same data. Hope it helps.

 

Big Boyz has a good calc but you have to watch it for determining ccp. Sometimes other valve timing events (other than intake close) come into play with ccp, especially on T-man cams. I as well as others have noticed this to the point I even set up a degree wheel to check intake close.
I like the 57H and 48H for a drop in 103" cam set. It all depends on if you want instant torque or a little more rpm, the 57H do respond well to headwork and a .030" gasket

 

FLS103- yep that is a good point, it is usually wise to use more than one tool in determining motor builds and upgrades. There are other good online tools from RBRacing, others. the BigBoyz online tool is great for quick general estimations of cam results based on your current measured stock static CR and CCP.

Can you list what other cam events affect cranking and cylinder compression? As far as I have ever known, the single cam event which dictates cranking / cylinder compression is the IVO/IVC. This is why plugging in the IVC number of a given cam gives you an accurate estimation of DCR and CCP. I may have misunderstood what you wrote.

the 57H / 37H are a nice drop-in choice if the estimated DCR will be better than 9.1:1 (ideally 9.2-9.3). If the DCR results at or less than 9.1 with the 57H, then going with the 48h will work great as it will get the DCR up. Since the 57h does not really come on until closer to 3k, if DCR is not within an optimal range (around 9.2) it is going to feel soft down low. Especially if the bike still has the overly tall ratio stock 32/66 belt pulleys.

A good thing you helped point out is that one should use more than one tool to estimate parts results for a given build, and, always take into consideration how the events of your chosen cam will affect your motor's operating compression (DCR and CCP).

 

FLS103- Ok I got it on what you are saying about other factors affecting compression, not so much CCP, but variances in operating compression due to things like cam overlap, duration etc. Good points to consider. Here are a couple of decent links which allude to what you're saying and are good for anyone wanting to read more on the topic of cam events, compression, etc. Both pages are well written and easy to grasp the basic concepts.

http://victorylibrary.com/tech/cam-c.htm

http://www.austincc.edu/wkibbe/camtheory.htm

Speaking strictly from a more simplified DIY'er point of view - for those looking to choose a drop in set of cams on a stock motor and don't have experience in engine building, or a good builder to work with, all you need to get close on good results on cam choice is a few short things:

1. Measure the cold cranking pressure of your stock motor with stock cams. From there you can determine static compression ratio as well. save those numbers. pay a shop to do this for you along with a leakdown test, it's a fairly quick process if you don't have the gauges. This is important information to have whether the bike is new (and broken in) or old, as it will show you the general state of your motor's condition.
E.g. you should not have more than a lb or two difference in compression between cylinders, decent compression numbers within factory spec, leakdown within acceptable range.
And, most important, you'll have starting CCP and SCR numbers to work with on cam selection. Without this data, you will only be *guessing* at how new cams will perform inside your motor and this is why many riders have different experiences with the same cams in the same model of bike. If you have this data and do the math beforehand, it will help you make a good informed choice on cams that work well in your particular motor.

2. Determine DCR and CCP of your new cams- before you buy them. For your new cams, look at the intake valve close event value. use one of the online calculators such as the Big Boyz website. http://www.bigboyzheadporting.com/TwinCamComp.htm
Based on your stock motor with stock cam's CCP and static CR, you can generally determine how the new cams will affect your Dynamic Compression Ratio (sometimes called "corrected compression"), or your cold cranking pressure (CCP).

3. Choose a set of cams that keeps your DCR around 9.2 and the CCP around 187-190. these are decent ballpark numbers that generally work in a typical performance street bike relatively stock motor with drop in cams. And in many cases, modified motors such as 107 kits, etc. Going lower starts to get soft on performance and going higher heads towards heat and ping territory.

* This school of thought can apply equally to performance builds. It does not matter if your static compression on a crazy street build is say, 11:1. It is your dynamic (operating) compression (DCR) and cranking compression (CCP) that matters- A well built strong running street motor will always be within tolerable operating DCR and CCP parameters, and it always is going to be in the area of 9.2-9.5 DCR and 187-200 CCP. The events of the chosen cams are responsible for determining the DCR and CCP of the motor.

* Consider your elevation when doing compression calculations. compression numbers will be vastly different well above sea level. my numbers at the beginning of this post are all at sea level, I live and ride mainly at around 100-1000ft above sea level.

 

short video today - idle and couple quick revs with the 48h cams. running very well - only thing is I'd like to try and get my idle MAP down closer to 30-32. it is presently sitting pretty solid at 35-37kpa.

 

Sorry to take so long to respond. This is strictly hypothesis on ccp...
Theoretically compression of the air/fuel mixture cannot start while the intake valve is open, however I feel it may start before the intake valve is fully seated. It is also my opinion that cams with faster ramp rates allow a bit more ccp than calculated simply because the valve closes faster. Using the same logic a slower ramp rate would have less ccp.
This hypothesis is from about 30 years of observations while building circle track engines. Some of the Lunati cams in my circle track days gave me fits. Certain classes limit the displacement and regulated the fuel, so one has to wring every ounce of power out of their build. Calculations were based on actual values...we cc'd cylinders, pistons, combustion chambers (with the proper heat range plugs installed), even factored in measured gasket thickness and the position of the ring land. Then you would order a custom grind cam and the ccp would be off by 10-12 points on all cylinders. Doesn't seem like much but when going for every bit of HP and torque without melting the engine it matters.
The SE255 cams do not match calculated values...even if you get **** and figure in elevation, temp, humidity and barametric pressure. Most T-man cams vary from calculated values, especially the 577 and 660. I used to blame advertised vs actual values until I got the degree wheel out. T-man bases his cams on Bob Woods profiles but uses a slower ramp rate. This is done in part to quiet the valve train, faster ramps are noisy . Take a Woods cam and a T-man cam with the same timing events and the Woods will have a higher ccp...it also has a faster ramp.
My build with T-man 577's should have hit 197 ccp corrected for elevation, it hit 190. No biggie but it made me wonder about my rings because I cc'd everything. Many others have had the same results. Sorry to ramble and stray from topic but cam events and ccp at times have given me fits.

 

Bike​​ sounds good!

 

Thanks FLS! Yeh it tuned in pretty easily- the only area that gives me fits is setting up new timing tables. this is strictly done by feel, reviewing log data, and lots of test riding. Really pisses me off to no end that DJ does not publish performance maps anymore that cover common rider upgrades of cams, engine kits heads etc.
Everything now in the tune library is "epa compliant" and nothing more than stock improved tune files. Pretty sad. Well at least the PV tuner itself is really good and will let me muck around with parameters as needed. But seriously I don't think the avg person could buy this PV tuner from DJ, install the 48h cams, and have any hope of the bike running right with a decent base tune. it's sad because the target tune wide band tuning is incredibly good. At least if you buy it from FM thy can help with a tune file. Heck I can't even set my cam timing events in the tune file without contacting someone at DJ to do it (hidden setting), and hoping they set it right in the file they send me. The first one they sent me for my 57h cams was wrong and bike would not run at all.

Yes you are correct that the actual is not always the same as advertised. but sometimes it is too. I got the relative same physical ccp numbers with my 57h cams as predicted by a few of the typical online calculators. I did not test the 48h yet but I can tell you it is indeed pushing something around 9.1-9.2 dcr. the diff over the 57h is about that much in felt performance.

I find the Andrews cams to be pretty spot on with their specs. Most everyone I've ever talked to or worked with that used an Andrews cam never had an issue with spec being off from advertised- at least AFAIK. .
Interesting to hear about your T-man cams experience- I am running the Tman 625 cam in my Evo Big Dog build and everything I designed in my engine builder (Desktop Dyno software), came out to within a very small margin of difference of the realized build. dyno results were also very close to the estimated HP and TQ. But I have heard many times from builders that the cam spec "actual' was off from what was advertised- I've just been lucky I guess and never run into that issue, but of course I have not build anywhere near the numbers of motors you have. Excellent "gotcha" point to watch out for.