M-8 cam specs

[1FSTRK]

I cannot imagine how anyone could try to develop a cam grind using more than one shop and dyno. Too many variables even when done in house with good equipment and techs.

These four valve heads expose a lot more curtain area and flow a lot quicker compared to a two valve head but air flow is air flow and once the flow and velocity are mapped the timing events and lift can be set to supply the engines demand. The engine doesn't know or care how many valves it has so the development process stays the same.

Now that there is a clean slate some will come out with cams that work and others will copy them changing a degree here and .010 lift there just like with the Twin Cams.

Good to see you guys working on the front side of this.

[HD/Wrench]

Short answer , no disrespect to you but thats your opinion.

I could write a massive post , in the end not hear to change anyones mind.. 

[1FSTRK]

Short answer , no disrespect to you but thats your opinion.

I could write a massive post , in the end not hear to change anyones mind..

Steve I am not saying this is not a complicated procedure, it is. All I am saying is that the procedure stays the same if they know how to develop cams, they know how to develop cams. If they do not, and have only worked off from other cams that work they will lack the crucial starting point.   

[rigidthumper]

The old "monkey see, monkey do" thing. I'm sure we've all noticed there are a lot of cams that have similar advertised #s, yet widely different power levels. I've seen dyno sheets with >10% difference in TQ/HP, and the two beta cams being tested were only 1/4° apart in timing numbers.

[joe_lyons]

Experience with victory's would probably help with the M8 cam setup.  Waiting for what S&S comes up with.

HPIs new throttlebody is setup to help with the flow discrepancy between front and rear cyl like the stock one has.  Idk if the flow discrepancy was on purpose from the factory for a reason and then some of the cams are designed to work with it as the new stg 4 cam has different specs front and rear and it's using the larger SE throttlebody.  So the HPI throttlebody may not work as well with SE cams.

[1FSTRK]

The old "monkey see, monkey do" thing. I'm sure we've all noticed there are a lot of cams that have similar advertised #s, yet widely different power levels. I've seen dyno sheets with >10% difference in TQ/HP, and the two beta cams being tested were only 1/4° apart in timing numbers.

With all do respect to your experience 1/4 degree in a HD with chain drive cams is not going to make any difference so it will not effect design or street bike numbers.

In a race/dyno shootout environment you may see some help with gear drives and off set keys but that is not what cam developers are working on.

[rigidthumper]

Absolutely correct, but my point is the numbers on the card don't tell the whole story.  On paper, these runs should have been very close. The cam card only showed 1/4 of a degree difference @ .050 lift on I & E. What happens on the way up to that .050" lift point, and the way down from .050" to seat, on intake and exhaust, make a very different camshaft.

[1FSTRK]

Would you post that graph with engine rpm instead of Wheel speed on the bottom axes and show the run conditions please.

[turboprop]

The old "monkey see, monkey do" thing. I'm sure we've all noticed there are a lot of cams that have similar advertised #s, yet widely different power levels. I've seen dyno sheets with >10% difference in TQ/HP, and the two beta cams being tested were only 1/4° apart in timing numbers.

This is all based on the assumption that cams actually match their published specs. I bet Max with his new flying merkel cam shaft test machine would say otherwise.

[boooby1744]

At the risk of sounding like I have been in a coma for several months..............
I just now noticed the opening closing events are slightly different for the front and rear cylinders on this cam?
Trying to wrap my head around that.
Emissions deal?

me too.

[wfolarry]

At the risk of sounding like I have been in a coma for several months..............
I just now noticed the opening closing events are slightly different for the front and rear cylinders on this cam?
Trying to wrap my head around that.
Emissions deal?

me too.

Offset TB.

[1FSTRK]

At the risk of sounding like I have been in a coma for several months..............
I just now noticed the opening closing events are slightly different for the front and rear cylinders on this cam?
Trying to wrap my head around that.
Emissions deal?

me too.

Offset TB.

Multi pattern cams and dual plane manifolds have been around in other type engines for years. They are often used to try and even up cylinder fill in engines that have some other type of flow bias but they are also used as a way to extend and flatten the TQ curve by making half the cylinders come in a little early and the other half come in a little later in the rpm band.

[guydoc77]

At the risk of sounding like I have been in a coma for several months..............
I just now noticed the opening closing events are slightly different for the front and rear cylinders on this cam?
Trying to wrap my head around that.
Emissions deal?

me too.

Offset TB.

Multi pattern cams and dual plane manifolds have been around in other type engines for years. They are often used to try and even up cylinder fill in engines that have some other type of flow bias but they are also used as a way to extend and flatten the TQ curve by making half the cylinders come in a little early and the other half come in a little later in the rpm band.

Makes sense in theory. Thanks for the explanation.
Begs the question though as to why only HD (doesn't appear that other SE cams or manufacturers have this)  saw fit to do this on M8 cam and only on the "Stage 4" cam.
It occurs to me that there will be a huge learning curve for all of us and "them" when it comes to hotrodding this engine.
Also, it is human nature to compare Evo and Twin Cam cam timing specs to the M8. I here and now resolve to STOP doing this reflexively as there is likely nothing to gain from comparing them. M8 with 4 valve heads is going to have a completely different respiratory system.

[NCTURBOS]

Tman has his posted for sale now, as of today...

https://tmanperformance.com/product-category/m8/

K.

[1FSTRK]

Just saw the dyno sheet for the S&S 465c with Stealth AC and S&S MK45 mufflers.
94 hp and 114 tq. Has anyone seen the specs for this cam?
Shows what a great effort Durwood and crew are making.

[Valley]

Found this.

[HD/Wrench]

Tman has his posted for sale now, as of today...

https://tmanperformance.com/product-category/m8/

K.

I think it is going to get confusing shortly as many of the companies are using 50 state legal parts , to show dyno sheets or parts of EPA legal kits .. The sheets are not going to show full potential.   Look forward to more testing that is for sure .  Like the 110 big bore kits  S&S does not do pulls in top gear to my knowledge and they have sheets showing like 100 and 117 for that kit yet all the people that are running them and tuning them are getting 7-9% more ..   Should be very interesting once more of these get out there and more testing is done 

[Sunny Jim]

Interestingly the SE cams with their multi pattern bisexual measurements compared to some one like Tman who has come up with a single pattern cam design. Is this important or is it the case that us DIY amateurs really won't know any difference.
In the end , you just want to know that your are buying a quality performance product that will perform as it promotes.

[K4FXD]

The factory has more money to test with.

They wouldn't put split cam designs on the market without some reason. What is the reason?

Unless and until more indy testing happens or the MOCO tells us, who knows if its power or emission reasons.

[1FSTRK]

The factory has more money to test with.

They wouldn't put split cam designs on the market without some reason. What is the reason?

Unless and until more indy testing happens or the MOCO tells us, who knows if its power or emission reasons.

Not really, testing budgets have always been a problem for bean counters.
As of late the EPA rules when it comes to what gets tested or out the door but HD has run multi timing stock cams in the Shovel head, Evo, and Twincams and all at differing amounts.

[K4FXD]

You know everything.

So Derwood and GMR and the other shops on this board have larger testing budgets than the MOCO?

I'll bet thats news to them.

[Ohio HD]

S&S has split pattern cams for the M8.

[Sunny Jim]

Ohio, yes I read that. I guess I am asking the obvious. Why split pattern cam as to single profile? I understand the intake has different lengths. Again, Why?
Are there long term tuning issues if we use these single profile cams?
Many questions

[Ohio HD]

From the OEM perspective, and I'm guessing, it might be to realize emission standards better, different temperature on the rear head? Just a guess though, and the S&S cam?

[Sunny Jim]

What's currently available:
SE cams
SS cam( gear drive)
  Tman cams
Wood cams.

Is the TTS and Cyclrama cams now available?
Are there any I have missed?