Performance Times

    4 Steps To Better Performance: Step 2 - Cams

    by George Smith / June 23, 2010

    4 steps to beter performancegeorge smith jrIn my last blog, I covered the gains you’d get by installing a set of S&S performance slip-on mufflers and an S&S intake system - either a teardrop air cleaner kit or our tuned induction system.  That's step 1 of our 4-Step performance program.  Today I want to talk about taking the next step.  Step 2.

    In Step 2  we add a set of cams to the mufflers and intake.  This will result in even greater power gains, but it requires someone with fairly advanced mechanical skills and technical know-how.  That's why we strongly suggest that the cam installation and tuning be performed by a qualified S&S dealer.  Any time you open an engine, there is a potential for trouble for an untrained mechanic who may not have the proper tools.  But just as importantly, installing a set of S&S cams will certainly require fuel system and possibly ignition tuning.  Although there are many riders who are excellent tuners, I would urge anyone who has any doubt about how it works to have your dealer take care of installation and tuning.  

    Step 2 - CamsWhen considering a cam change there are several things to think about.  The first is the kind of riding you will do, and the second is how far you intend to go with performance modifications.

    If you are a drag racer, you are looking for the most horsepower you can get but a touring rider wants more midrange torque.  The racer is going to launch hard and wind it up from there.  The touring rider is just the opposite.  They’re more concerned with being able to roll it on and easily pass a semi or go up a big hill and will probably rarely rev the engine over 5000 rpm.  So high rpm horsepower really doesn't matter.  These are two very different applications and require two different cams.  For the owner of a 2007 or later big twin who wants top end horsepower, I'd recommend our 585 cam.  The touring guy should consider our 551 cam because it is a midrange torque monster.  Our 583 cams are somewhere in between.

    If cams, pipes, and intake are all you intend to do to your bike, you should choose the best cams for that configuration.  If, on the other hand, you are going to install a big bore kit and have your heads ported later, you may want to go with a cam that may not be the best fit right now, but will be killer when it all comes together.  That's a personal choice and  something to think about.

    One product I recommend to anybody considering a cam upgrade for a 1999 and later big twin, is the S&S Easy start cams.    These cams are the latest S&S innovation and have an automatic mechanical compression release built into each of the exhaust cam lobes.  At cranking speeds the compression release is active, releasing a little of the cylinder pressure so the starter can easily turn the engine.  When the engine starts and rpm increases, the compression release is centrifugally withdrawn, and the engine runs at full compression and power.  The result is that with Easy Start cams, a stock starter and battery will start just about any engine – regardless of displacement or compression ratio.  What's more it will start it repeatedly without wearing down the battery! 

    During development to test these cams, we built an automatic control box and hooked it up to a late model bike with Easy Start cams.  The control box automatically started the engine once every minute, let it idle for about 30 seconds, and shut it down again.  This cycle repeated over and over.  A great test, but it can be a little unnerving to have a riderless bike starting up and shutting down by itself.  One of our test bikes had over 30,000 consecutive starts on it before we pulled the plug.  The amazing thing is that during the test, it never ran down the battery.  When we tore down the motor to inspect it, everything was fine.  S&S has a display that we bring to the major rallies that demonstrates this.  You can see it at Laconia and J&P open house  in June, and at the Sturgis Rally in August.  View our event calender here.

    In case you are not convinced, here's another demonstration of how well the Easy Start cams work.  We took two identical bikes with stock 96" stock engines, and installed our 585 cams in both of them.  One bike had our standard cams and one had Easy start cams.  We put a brand new, fully charged battery in each bike, pull the spark plug wires off, and hit the starter buttons.  Within a minute the bike with standard cams had ground to a halt, but the one with the easy start cams just kept on going - like that rabbit beating the bass drum in those TV commercials.  We re-attached the plug wires on the bike with Easy Start cams and it started up instantly.  We made a video of this test in case you want to check it out.

    So to conclude for this week, in Step 2 we added a set of cams and a big performance boost to last week’s Step 1 air cleaner and mufflers.  Remember, if in doubt, to have a qualified S&S dealer do the installation and tuning required to make it work.  I personally recommend the S&S Easy Start cams - your battery and starter will thank you.

    Next week we’ll talk about Step 3 and bolt on an easy to install big bore kit to bring that 96" engine up to 106", or that 88" engine up to 97".  Until then. . .

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