Seems like the cam subject comes up a lot. I have to ask.

In a stage one application with say a power vision tuner. Two guys, both have 103' in a street glide.

A. Puts a 555 in his bike.

B. Puts a 575 in his bike.

Without raising compression. Wouldn't the power output be negligible?

I'm thinking 2/3 horsepower and torque?

It's like I see guys really over camming their bikes without adding the proper supporting mods.

 

I'm not sure what you are asking. Many different .555 and .575 cams to choose from. The timing of the cams will make a huge difference and is more important than the rise of the cam. For a stock 103" chasing torque you cannot go wrong with an Andrews 48. If chasing a bit more HP then an Andrews 57. Both are solid performers.

 

Ok.....I guess after playing with cars for the last 30yrs. Big blocks, small blocks, Nitrous, turbos, blowers, etc.

I've never seen as many debates and options for cams. The marketing is insane. My cam does this, my cam does that. 10 different cam gurus!

What are we trying to dial in.....a 900lb touring bike! Hahaha..... give me a break!

I think a lot of money is to be had by being, that guy! Or the flavor of the day.

 

I don't think the 555 is really going to shine with stock compression look into the Andrew's 48

 

Dunno why you are stuck on those cams??? If all you want to do is use the Power Vision and add a new set of cams with stock 103 compression, then the Andrews 57H is your answer.

Now if you are going to make other gasket/head/etc. modifications, then that's different.

Regardless, have fun working through the process.

 

Cam Science has chanced a lot over the years, it's not just more lift that makes a performance
cam anymore. Cam timing, lift, duration, lobe separation, or having a dual pattern cam has a
lot to do how they work and perform in an engine. Two cam with the same lift can perform in
two different RPM ranges, some are lower end torque cams others can be mid to top end cams.
The cam manufactures will give you an range where the cam will work with your application.
That being said, a lot of people over cam an engine, and it dose not work in the range that they
ride on a day to day bases.

 

Dialing in a 900lb touring bike......doesn't that sound kinda funny?

Sarcasm........no one gets it except me. Oh well......lol!

 

Lot of truth to what you are saying.. It is called "The Cam of the Month Club"

But considering that once you have the engine breathing well (intake/Exhaust) and a have a tuner to support that you can now easily get 10-15 HP/TQ improvement then there is a lot of bang for the buck in changing out the cams and little downside if sticking with lifts that are compatible with the stock springs.

The Cam's of the Month can IMO be broken down into the milder ones that essentially get you to what the bikes should be rolling off of the floor with were the MOCO's hands not tied by epa regulations to what are a decent boost up from that and that tailor the delivery to suit a persons riding style more...

As for "Dialing in a 900lb" motorcycle .. well they all need dialing in to some degree regardless of the weight. I've got a 390lb Ducati in the garage and it's isn't stock although I've never felt the need to upgrade the cam.

 

I've got a 390lb Ducati in the garage and it's isn't stock although I've never felt the need to upgrade the cam ... Well, obviously he doesn't have a 390 pound scooter. Right?

 

Camshaft selection gets a lot of coverage, and it should. Even with all the great cam selections out there these days, folks still get into trouble quickly not picking the right cam for what they are doing.


Simply installing a bigger cam without raising compression and similar lobe positions will hurt power (torque) at lower rpm's and degrade idle quality some. It takes close to a full point of compression for every degrees of additional seat timing to offset the negatives of a larger cam install.


This fact is missed by many when selecting cams. I chuckle to myself when I see someone recommend a larger than stock cam and no other changes and tell the end user it will make "more torque". Could be true, but where is it going to make more torque at? Will it hurt idle quality, off idle power, low speed power, fuel economy? With big heavy touring bikes two up off idle power is a big deal, as it engine efficiency at lower rpm's.


LSA is a big deal for cam choice as well, and will effect the power range of the cam, and also effect peak cylinder pressure and where in the rpm it is made at. "Tight" LSA will increase overlap, make the exhaust stink more, more aggressive idle sound, and tighten up the power curve some. It will make a higher peak torque number earlier in the rpm range than the same cam on a wider LSA if installed in the same position.


Wide LSA reduces overlap, increases vacuum at idle, and flattens out the power (torque) curve some. It also reduces octane requirements at the same time. Typically engines with wider LSA cams in them "feel" less powerful than the tighter LSA stuff, as they don't throw power at you as quickly or as early in the rpm range, so basically produce a "boring" power curve compared to a power curve that hits you hard more like a shot of NOS.


Since I do this for a living we get involved with a lot of V-8 engines, and dyno all of the ones we build here, then install them in vehicles and street/track test them, we get to see the entire deal start to finish. For HD engines we hire folks in that industry who have a lot of experience and dyno time under their belts. That is usually the best way to choose a cam for your HD engine, and other mods to go with it. Find a shop that really knows what they are doing base on a lot of real World experience. You still have to be selective with shops as some are ALL about big dyno numbers and don't really pay a lot of attention to idle quality, off idle power and engine efficiency in the "normal" range you will use the engine in.


I saw this deal play out first hand with a good friend of mine. He hired a shop to install his stroker kit, high compression, big cams, ported heads, S & S carb, etc. It made FANTASTIC dyno numbers, but was a complete pile of shi@ in actual use. Sure he could blast past everyone and fill our lungs with black smoke from his exhaust, but he couldn't get much past 100 miles on a tank of fuel on long rides when the rest of us were going 170-180 miles on the same amount of fuel. He also had hot start issues, and his engine was a tad "soggy" two up right off idle and at lower rpm's.


Some very knowledgeable folks respond on the websites on this topic, but it can be difficult to separate those regurgitating information with very little if any hands on experience from those who really are the deal when it comes to these things.


I see the exact same thing on the Chevy, Olds, Pontiac and Buick websites as well as on my own website. I guess there are a lot of folks throwing out information on these subjects with about as much real time doing it as I spent on the crapper last week. With this in mind, proceed with caution when making your cam selection, and for sure don't be afraid to put some compression in these engines for improved results with bigger cam selections. Compression is power, and efficiency when it comes to these things......FWIW......Cliff