Narrowed main bearings present less surface area and, consequently, less parasitic frictio
When talking to engine builders, we were given several ideas that were good with the exception of one small problem: legality. Although we don't want to promote blatant cheating in racing, it's common knowledge that the best place to find a perfectly legal race car is in the back of the pack. With that in mind, we offer the following tips that push what we'll euphemistically call the "gray areas." We chose these because we thought they would either be particularly hard to spot, or in areas not normally checked. Still, adopt these strategies at your own risk. Remember, the tech man reads us, too.
You may need to ask an engine builder for help with the following. Excessive surface area on the main bearings can cause unnecessary drag. If your crate motor utilizes OEM bearings, they can probably stand to be narrowed by as much as 0.1 inch. Make sure you don't expose the oil holes or you will lose all oil control. Similarly, narrower, low-tension piston rings can really save on parasitic losses, but this involves getting past all of the "tamper-proof" seals that your engine probably came with.
While you have the bearings out, you might also consider a performance-enhancing coating designed to attract oil and aid lubricity. Just be careful, as some of these add a colored patina to the bearing that is easy to spot.
Racing water pumps like this unit from Moroso take into account that coolant flow at idle
Pushing fluids through the engine soaks up power. Minimizing oil pressure to cut parasitic losses is old school in traditional racing engines, but that ability is typically limited in crate engines. If you can get the oil pan off, however, this adjustment is pretty easy. By simply putting a lighter spring in the oil pump, you can reduce the workload on the pump. It's unlikely that someone is going to tear you down to check your oil pump spring.
The same goes for the coolant flowing between the block and the radiator. This tip isn't useful if you are allowed to use a racing water pump, but if you are using an OEM unit, you are likely pushing too much water through the block a lot faster than necessary. OEM pumps are designed to provide adequate cooling for street cars, which spend 90 percent of their time between idle and 3,000 rpm. Oval track stock cars are high-rpm monsters, and cooling during extended rpm periods at low rpm is not a concern. If you can get your water pump apart, cutting every second vane off the impeller will reduce water flow to more manageable levels-you'll just need to make sure your ducting and overall cooling system works effectively. Also, it's probably best to cut the vanes off on a milling machine. A hack job will unbalance the impeller and lead to power-robbing cavitation.
Many crate engines currently being designed for racing are rpm limited. The limit is often below peak power levels. If you are hitting the rev limiter but the valvetrain still seems to be holding up, you can potentially free up some power by using lighter springs. Instead of changing the springs, which can be easy to spot by a tech man, lower the seat pressure by going with thinner spring shims or cutting a few thousandths of an inch out of the spring seats.
Don't do too much or you may make the springs too weak to do their jobs. This is another area where a qualified engine builder can be helpful, both in determining the minimum spring pressure you can get by with and in making the cuts on the cylinder heads.