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Mopar Circle Track Racing

by "Blue" Mike Peterson, Schofield, WI

I've read some fine articles on this site about drag racing EEKs, and have benefited from technical suggestions and set ups. I apply them, however in a lesser discussed application to wit: circle track racing. 4 cylinder mini stock racing is sweeping the heartland. Fans absolutely love seeing a field of Dodges, Fords, Chevys, yes, even Toyotas and Hondas, anything but the GM metric chassis Monte Carlo.

Cars and parts for 4 cylinders are readily available, and surprisingly, a stock 2200 lb 4 cylinder car with a stick will turn a respectable 17 second time trial on a typical slight banked 1/4 mile asphalt track.

I personally run a Daytona/laser type set up, 2.5l TBI, with a five speed.

A couple years of experience has shown me in a circle track application, I can do a lot of things under the "stock" heading to be competitive against all mini stocks' enemy, which is the Ford Pinto/Mustang II and the 2.3l (reason being is the Ford as a 4 cylinder qualifies for most mini stock classes, and they are rear drive so they can benefit from all the racing books and lectures and data based on front engine, rear drive set ups, plus the 2.3l has tons of aftermarket parts reasonably cheap).

A lot of these tips may not work for drag racers, but if you are a circle tracker:

1. Lose all the rotating mass you can. I've found I could shave heaps off the flywheel, however leave the immediate area around the mounting bolts alone. You can lose most of the weight off the BACK of the flywheel (face to the engine). I shaved it flush to the gear teeth with no problem.

2. Another 10 minute reduction; drop the cover off the side of the trans and take off the "5th gear" stuff. All of it can go in a box, just be sure the linkage pegs move freely, and you don't compromise the gasket on the other side of this sandwiched addition. If you have the ambition, and are comfortable digging deep, out of this cover you can gut the whole tranny! I took the 2nd and 4th gears and had them thoroughly machined so they only act as basically a bushing taking up their place on the shaft. Granted I have to run first way up to 4,500 rpm, then lug in 3rd until I'm up to parade lap speed, but what a gain in "snap"!

3. Racing fuel is hard on 02 sensors, so I run 2% nitro methane, available on the net from Price Chemical which comes mixed with all the good stuff to run reasonably safe. I have a switch on the dash to disable the O2 sensor, putting it into a full rich condition which is excellent while competing, however you need to switch it back active or she'll flood out easily at low speeds.

4. The 88 and older 2.5 blocks will take a flat top stock 2.2 piston, and you have instant high compression. This last year I made the mistake of settling for a newer block in desperation to have it back from the motor shop by race day. Forward motion does have flat tops for these newer ones, but be sitting down when you hear the price, $450! I'll tell you this though, these pistons are indeed trick, light, balanced; they are indeed a great marvel of machining, just perhaps a little too steep for me. Shaving the head .060 is of some conciliation, just watch those plugs and look for detonation!

5. I found a pleasant gain in performance by thoroughly insulating the exhaust heat from the intake manifold, as well as other sources too. Go to a local fleet farm or fire place shop, they sell 5/8 strips of "door gasket", obviously to seal a wood stove's door. Get 10 feet of it, (and the goo to cement it on), and wrap the exhaust manifold top to bottom, wherever you can, providing you leave room for it to run in between the intake runners. Use light tin or metallic tape (used in body work) which is highly reflective, on the bottom of the intake to deflect radiant heat, build a plate of light tin to go under the TBI gasket to dissipate heat, or your own version of a phenolic spacer; and why you're at it, make this spacer as high as you are willing to run around town and find bolts long enough to still get the throttle body on. Mine is 1 1/2 high!

6. I have found an excellent cam that cooperates with the computer. It's a comp cams part# 22-131-4, about .460 lift, 236 duration. The computer has little trouble accepting this change, other that it tends to hunt at idle a bit much.

7. My last piece of advice, from my experience is the 2.5 makes good power at low rpms. Even though it sounds like you're crawling at 5,000 rpm when the other guys are spinning 6,500, look at your lap times, and surprise! You are right along side! This does offer quite a benefit in longevity too.

I hope more circle track mini stocks try the trusty MOPAR, It works, ain't hard on the budget, and as always, running a Mopar makes you the coolest rebel on the track. HAPPY RACING!

"Blue" Mike Peterson
#4 CENEX Mini Stocks

P.S. If any of this is of help, please return the favor and e-mail me with any ideas you find works. Thanks! e-mail me.

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