Because the car counts are...
Because the car counts are still high and the competition is great, many racers with the skills to move on to the V-8 classes prefer to remain in Mini-Stocks because they can be a lot of fun when done right.
Mini-Stock racing will always be among the most popular among stock car racers. The Mini-Stock classes are great for beginners because the smaller four-cylinder engines limit speeds by keeping power in check. Also, fewer cubic inches keep the cars more equal, even if one car is running an illegal engine. Rules designed to keep costs in check also make this class more appealing to many racers running without the advantage of a fat wallet.
But good car counts and great competition mean that Mini-Stock racers are always looking for any advantage they can get to stay ahead of the pack. And you'd better believe smart racers and engine builders have found ways to be faster.
With that in mind, we've compiled a list of top tips to help with your Mini-Stock program. So no matter if you are racing in the Young Guns class or the Mod Fours, whether you prefer the traditional Ford Mustangs and Pintos or you are among the growing ranks of racers campaigning Toyotas, there is something here for you.
We'll begin with ideas for helping you produce more power while still getting good durability from your engine, and then we'll move on to ways to improve the handling of your chassis.
In high-rpm race applications,...
In high-rpm race applications, drag from the piston rings can lead to a serious loss of horsepower. Smaller metric rings, such as this 1.2 mm, 1.5 mm, 3.0 mm combination in your Ford 2.3 motor, can free up a little power.
Mini-Stock engine builders say that one of the great challenges when working with Ford's 2.3 liter four-cylinder engine (far and away the most popular engine in the Mini-Stock ranks because it is durable and plentiful), is getting power from the limited displacement. One way to get around the displacement limitation is to spin the rpm's up to buzz saw levels. The overhead valvetrain geometry allows this, but when the rpms reach-and often exceed-8,000 rpm, friction losses come into play.
Then the focus turns to reducing horsepower losses caused by friction inside the engine. One great area for this is the piston rings. Stock 2.3 engines use standard ring packs, but this really isn't necessary in a racing engine. Engine builder Ken Troutman of KT Engine Development says he has found you can safely reduce both the ring size and tension considerably without damaging either the engine or power output. Normally, he says he switches to a metric ring pack designed for import motors that measures just 1.2 mm for the top ring, 1.5 for the second and 3.0 mm for the oil ring. These rings are not only thinner, but they usually also have less radial depth (thickness from the inside to the outside edges of the ring) which results in less ring tension.
Using lighter rings like this requires good cylinder honing procedures or else you will never get good ring seal-so spending a couple extra bucks to hone the cylinder with a torque plate in place is imperative. This package is catching on and while it previously required an expensive set of custom pistons, many suppliers, such as Race Engineering, are now keeping Ford 2.3 pistons with ring lands sized for metric rings as a shelf stock item.
Nitriding is a surface preparation...
Nitriding is a surface preparation that both hardens and adds lubricity, or slickness, to metal. A nitrided cam is easy to spot because it will be flat black.
The overhead valve system in Ford's 2.3 motors is both a blessing and a curse. The geometry of the design makes it capable of 8,000 rpm without losing significant valve control. But it can also be difficult to get an aggressive race cam with big lobes and aggressive ramps to live for any length of time. This is especially true if you are allowed to run solid lifters.
One solution used by many engine builders is to have their cams nitrided. Many manufacturers, such as Comp Cams, are offering nitriding as a service directly from the factory. Nitriding is different from surface hardening. The nitriding process uses ammonia gas and high temperatures to infuse the cam with a ferrous nitride on the surface. That's a bunch of geek-speak that means the surface of the cam gets a lot harder and slippery. Both of these factors are good because there is no such thing as a roller lifter when racing the Ford 2.3. A nitrided cam will be more expensive than a standard cam, but many engine builders say that the extra longevity you get from the cam will offset the price.
Stock four-cylinder Toyota...
Stock four-cylinder Toyota engines have a single-row timing chain. Give yourself a little peace of mind by upgrading your Toyota race motor with a double-row timing set for greater durability.
LC Engineering specializes in building high-performance Toyota four-cylinder engines. Toyotas are gaining popularity in Mini-Stock racing because they are a good design, and with all the Celicas and Camrys out there, blocks and heads are still plentiful. One problem with Toyota's four-cylinder design is it only comes with a single-row timing chain. LC Engineering's tech department recommends upgrading that to a double-row chain so that it will hold up under racing stresses. The timing chain itself isn't an expensive component, but a timing chain that breaks at speed will result in broken valves and expensive engine damage. To fix this problem, LC Engineering has designed and sells an upgrade kit for a double-row timing chain. The kit comes standard on all race engines sold by LC Engineering.