Rpm Limiters and restrictor plates on face value seem like a very simple cure for many of the problems we see in racing, and an aid for the budget racers.
![Smile](https://www.indianaopenwheel.com/images/smilies/smile.gif)
What is involved when we put these limits on racing? First thing off the bat it means hours and hours on the dyno. We will be looking for new cam profiles. injector sizes, header designs, compression ratios and on and on. All of this experimentation costs money and will go down many dead end roads while looking for the right answer.
NASCAR teams have divisions that do nothing but restrictor plate engine development. In many instances the restricted motor turns just as tight an an unrestricted motor it just takes longer to get there. The rev-limiter motor accelerates just as fast however it is limited to peak rpm's. Both theories require experimentation to achieve maximum performance and that puts the racer with the most money to spend on development once again out in front.
Most racers have yet to grasp the advantage of the 4 valve motor over a 2 valve motor. The cam in head 4 valve is superior to the push rod 2 valve motor in two distinct areas. First and fore most is Volumetric efficiency (VE) >>> How much air can the engine draw in over all of its operating conditions that the engine is expected to perform in. The 2 valve motor can flow as much air as the 4 valve can however to do it it requires a very large intake valve and very high lift and very long duration cam shaft. That means that the 2 valve motor can produce lots of horsepower at high RPM's but at slower speeds it looses most of it's efficiency and performs very poorly. Because of those extra valves the little 4 valve motor has a much higher VE both at high speeds and at lower speeds. That means that the racer can use a much lower lift camshaft and also use a very mild (almost stock) cam profile and have VE equal to the 2 valve at high RPM's and because of the cam timing and valve lift it can also be very efficient at slow RPM's.
The second advantage is that the use of small light valve without the mass of push rods and rocker arms allow these motors to use lighter weight valve springs with the lower duration and lift camshafts and rev just as high or in many instances much higher than the 2 valve motor is capable of. A big advantage is they require much less maintenance with the milder camshafts, and valve spring replacement will become a task of the past.
The jury is still out. Basically there are now two schools of thought. Both schools have elected to require Stock crank shafts, cylinder blocks and heads a very positive choice. Neither are allowing changing of the ports by porting or welding. One class is mandating stock pistons, valves, and camshafts. The other has allowed aftermarket valves, pistons, engine internals and camshafts. So the question would be how much advantage can be expected with these changes. I see somewhere between 15% to 20% in power from the Badger rules with most of that coming from that extra compression.
Don't make it complicated.
Remember the engine you are racing today should have disappeared in another 5 years and will have to be replaced to keep cost in line.
Engine displacement is being lowered with the use of inexpensive forced induction to achieve the same or better performance, (start thinking about this development. It is already in use today on inexpensive family drivers right now)
Gang "Times They Are A Changing"
Honest Dad himself
![Thumb](https://www.indianaopenwheel.com/images/smilies/thumb.gif)
![Thumb](https://www.indianaopenwheel.com/images/smilies/thumb.gif)