Auto Racing: 91 geo storm race car, piston crowns, real race cars

Question
Hello i have a question about how to get just a little extra power out of a Geo Storm. The car is set up really good I can just about turn the car in the grass if I want to. This is a circle track by the way 4/10 mile asphalt. We are allowed 1 degree of camber in the rear and 4 in the front. I have 4 negative on the rf, 1 negative on the lf and rr and the lr is straight. The car is supposed to be stock as far as the motor is concerned. I've taken every ounce of weight I can out of the inside of the car but haven't really touched the motor because while I really don't care if it's stock it needs to look stock because they don't tear them past the valve cover and don't know what they are looking at in the oil pan. I put a little rear steer in it to make it handle better and we got it handling pretty good. I'm still missing about 4 tenths of a second and as you know on a short track thats a lifetime. I know more about rear wheel drive stuff and real race cars not these little 4 cylinder pieces of junk. Anything you know that can give us a little more power or perhaps make it handle even better to get up off the corner better to produce some faster lap times?

thanks

Answer
Hi Sammy:  

Getting off in  a small bore is always a problem.  When you freshen the motor, use Total Seal rings (www.totalseal.com) make sure you've got about .004" of piston to wall clearance, right at .002" on the rod bearings, and .025" to .003" at the mains.  Crank end play should be in the .005" range.  

While you have it apart, deck the block, mill the head, and make sure your valves still clear the piston crowns by mocking up the motor with clay and turning it over a few times.  measure the thinnest part of the clay with a vernier dial caliper and make sure the valves clear the pistons by about .010"  (100 thousanths ) You can try advancing and retarding your cam timing by one tooth, or get a degree wheel and time the cam to exact specs.  Usually stock cams open the intake about 14 to 16 degrees BTDC. The rest of it falls in place and there's not much you can do about it. Finally, lighten the flywheel as much as possible and re-balance the whole works.  If you have an extra $6-700, switch to forged pistons, typically they are about 100 grams lighter (about 3 ouces each) and there are a pony or two hiding in that reciprocating weight. Plus they just work better.

Now, regarding cams,  if you[re brave you can use my friend at Cam Techniques, he will make you a cam with stock lift but more duration.  It helps. try(www.camtechniques.com) and drop him a note.

Next. Front end:  go to about 2 degrees positive on the LF, the allowed 1 degree Neg. on the RR and 1 degree positive on the LR..  Try setting your toe to 1/32" OUT on each wheel for a total of 1/16" and experiment, some late models run as much as 1/4 toe out to help the car turn. Also "caster is faster"  Shim or shorten the radius rods (or tension rods) to gain caster. Most cars have about 2-3 degrees, 5 is better.   The car should be easy to steer on track but a real BEAR in the pits.  

Rear End:  I would add a sway bar, about 3/4" chrome moly tubing, andmake it adjustable. Then change the spring rate to stiffer. You want to loosen the rear.  This will add to the effect of the rear steer you have, so go easy at first. However, taking the twit out of the body with the rear bar will do wonders for the handling, and the overall feel of the car.

That's all I can think of at the moment, but please feel free to write again. I am willing to help as much as you need.

Thanks

Dan Liddy
Sarasota, Florida