Thin is in when it comes to motor oils. Modern synthetic blends have made it safe to use thinner motor oils than ever before. With a well-built race engine, most engine builders feel that a 20W-50 motor oil can provide more than adequate protection. But many Cup teams regularly push the limits with ultra-low-viscosity oils because there is power to be found there. Of course, Cup teams can also afford to rebuild their engines after every race, unlike most of us. But if the season is wrapping up and you know you are going to have to spring for a rebuild anyway, trying an ultra-light motor oil is no longer such a big gamble.
The same thing holds true for your transmission fluid and even the gear lube you are running in your rearend. Lighter oil in any of these three places should translate directly into more power being transferred to the ground. You just have to determine how thin you are willing to go.
With stock cylinder heads,...
With stock cylinder heads, you can sometimes find more power by advancing the timing a couple of ticks. But you will have to be constantly vigilant for detonation.
FLIRT WITH DETONATION
In the lower-level racing classes, where stock or stock-style cylinder heads are the rule, proper ignition timing is almost always about finding maximum power before costly detonation becomes an issue. If you are running a nice set of aftermarket cylinder heads with efficient combustion chamber designs, this tip may not be helpful because your motor may not need as much timing advance to make maximum power. But with stock-style heads you can usually make a little more power by advancing the ignition timing an additional degree or two. And since we are talking about end-of-season power tips, the lower air temps you are likely to see can also help ward off detonation. Just don't assume that advancing the timing will always make more power. If you do not have access to a chassis dyno, spend a little track time seeing just how far you can go with your ignition timing before detonation sets in-and how those changes affect your lap times.
Tightening up the valve lash...
Tightening up the valve lash can make the camshaft act bigger.
If you are running solid lifters, you can try setting your valve lash a little tighter. Tightening up the lash by 0.001 or 0.002 inch will allow the camshaft to activate the valves sooner, essentially fooling the engine into acting like it has a larger cam in there. Sometimes this will help produce power, but if the best camshaft possible is already in your engine, closing up the lash will only make it more sluggish.
This means that you will have to do a little experimenting to determine if closing up the lash will be helpful or not. Also, if you have been adjusting lash with the engine cold, you will need to find out how much the lash changes when the engine gets hot. What you must avoid is closing up the lash so much that the valves never fully seat and, as a result, do not seal off the combustion chamber completely.
The next time you have the car on jackstands, take inventory of your entire driveline-from the crankshaft back. Are there any components between the flywheel and the brake rotors that can be lightened up? For example, switching from a stock-style flywheel and clutch to lightweight racing components can shave 10 pounds or more of rotating weight. The same thing goes for using an aluminum driveshaft instead of the stock chunk of steel the factory uses. The more mass the engine has to spin in order to get the wheels turning, the more horsepower that gets absorbed before it can do any good.
Technically, this tip doesn't help your engine produce more power, but it does ensure that your engine is able to efficiently transfer the power produced to the ground. And if it translates into faster lap times, all the better.
Well, there you have it - 10 tips that will hopefully help you add that extra oomph you need to grab that title or capture that first win.
AND ONE FOR THE ROAD
Just in case you felt shafted by one of these tips, here's an extra:
These stamped-steel rockers...
These stamped-steel rockers look like stock 1.5:1 Chevrolet units, but they are actually 1.6:1 rockers from Crane. It isn't much, but it is definitely worth power if you are racing in a class with a limit on maximum cam lift.
If you are running in a Street Stock class, rules usually require stock rocker arms. On a Chevrolet, for instance, the stock rocker ratio is 1.5:1, but several companies, such as Crane Cams, produce higher-ratio rockers that are virtually indistinguishable from their stock counterparts. Crane produces a 1.6:1 rocker. While that may not sound like a big change, it can usually produce a little extra power with the same camshaft. Also, the increase in rocker ratio isn't so much that it will cause piston-to-valve clearance issues.
Increasing rocker ratios in other higher-level classes is also an option. A new set of rockers isn't terribly expensive, and changing them doesn't require tearing into the engine. Just don't try to make an extreme change. If you do, you may run into problems such as requiring a change in pushrod length, clearance issues for the pushrod holes in the cylinder heads, or even spring failures. Also, make sure to recheck your piston-to-valve clearance. You should have 0.080 between the intake valve and the top of the piston at 10 degrees after TDC. For the exhaust, you should have at least 0.100 between the valve and piston at 10 degrees before TDC for that cylinder.