Explaining How Cams Work and What the Numbers Mean

[truckinaround25]

I have a bit of an agressive build on my '06 FXDI and would like to know if this would be the proper forum to ask if my build "works---theoretically"

thanks in advance for any help

"There is no scarcity of opportunity to make a living at what you love to do, there is only scarcity of resolve to make it happen."

[claydbal]

truckin, just ask. if the mods think it belongs in this area, it will stay, or conversly, they will move it. just dont hijack this thread------leave that for me . LOL

[gizz46]

I installed a S&S 510G in my stock 2002 FXD TC88 more for the gear drive than any thing, Now that said and done, Should I do any thing to make this set up work better?
I do not race, I just thought the gear drive was the way to go at the time.
Thanks

[gmdoctor]

Awesome articale, well written!

[Motorhead1257]

Hey Great Post !!! Now I have a question, which would be a good "gear driven" cam to be used in my 03 fxdwg TC 88 all stock. Trying to eliminate the cam chain tentioner issue
that it might face in the near future if I don't. It's got 8,000 on it now.

[Carsty1]

Question Please.....
05' RK, with carboratior,high performance air filter and VH 2 into 1 pro pipe. I'm am upgrading to bigger cams and adj lifters....to optimize performance, not changing the top end, would i need to change the ignition and coil before doing a dyno adj ? thanks....

[Fatmel]

Originally Posted by Totenkopf

No I don't think it changes the cam design really. You need to size the cam for displacement and rpm where you want the power band to be.

What a longer (or shorter) stroke does, is it can change the intake port and intake manifold requirement to some extent, depending on how you approach the design. There is some school of thought on having a subtle choke point in the intake tract one stroke length out from the valve seat. Then you would ideally like the intake plenum behind the choke point to have something like 27% of the cylinder displacement volume in reserve, pressurized from the intake pulse waiting for the valve to open.

Tote I'm looking at SE255 cams in a 103 engine. Is it too much,too little or ok. I mostly operate in that 2500 to 4500 rpm range. For an 08 street glide

[braato]

i recently installed andrews cams in my '01 CVO road glide and cant find a procedure to ensure my oil pump is doing it's thing
Can you offer any insight to this last ,but very important check.

[gid58]

Originally Posted by Totenkopf

No I don't think it changes the cam design really. You need to size the cam for displacement and rpm where you want the power band to be.

What a longer (or shorter) stroke does, is it can change the intake port and intake manifold requirement to some extent, depending on how you approach the design. There is some school of thought on having a subtle choke point in the intake tract one stroke length out from the valve seat. Then you would ideally like the intake plenum behind the choke point to have something like 27% of the cylinder displacement volume in reserve, pressurized from the intake pulse waiting for the valve to open.

My brother,,in the old days,,and still,,they had small bores,,long strokes,,,which made an turbulent effect on how cams performed at high velocity,,,THANKS,,to G2 and others where they are now offering 5" and smaller bores,,with really short strokes,,that not only help unshrouding,,,but also offering a slower piston speed to help a cam from perform,,,,what it should do instead of,,,(if you will backwashing,turbulent,,etc),,now we have an engine,,that is more eff,,in filling and potent,,powerful like the Japanese been doing for years,,A cam is important,,but if you put it in the right enviorment,,big boar decent stroke,,a cam can even be smaller,,ie,,unshroudeness,,port velocity,combo, and less hard on valve train,,and really kickass,,cams important,,but if you start with a big headed mule,,he can work for less feed!!!! Talk to me!!Thanks

[lostagain]

if the answer is AIRFLOW . With the pump being the cam. What role does the fuel body play in the performance equation.And What advantage in airflow would you get increasing from a stock up to a 50 mm throttle body if any?

[Otto]

Originally Posted by lostagain

if the answer is AIRFLOW . With the pump being the cam. What role does the fuel body play in the performance equation.And What advantage in airflow would you get increasing from a stock up to a 50 mm throttle body if any?

the advantage would be less intake track restriction think of the intake port as a long slender funnel the fastest air speed would be at the narrowest portion or at the outlet end you want the air to accelerate down the intake runner to the valve in a controlled manor if you have a spot that is smaller then the outlet that is where the fastest airspeed will be just for sake of argument any faster airspeed than approx 425 fps kills peak torque and hp due to drag a throttle body that is to small will have high air speeds due to turbulance around the shaft and butterfly while this wont hurt low speed drivability it will kill the peak numbers and seeing that is the only numbers that can be measured that is why increases in tbody size will show improvements on the dyno
or seat of the pants

[Fourcats]

Great stuff...

It all boils down to the numbers {in the checking account}

[aj419]

I just purchased a 2013 street glide and I am considering a woods 888 which is very aggressive/powerful. My only concern is noise...Any advice

[C-Cat]

555/777/888's are Woods newer series of cams and all quiet. I got the 777's in my RG and they're quiet.

[BrianHeiting01]

Great post! It was very thorough and got straight to the point.

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