The Saturday-Night Buildup...
The Saturday-Night Buildup car really came alive with the addition of a set of L31 Vortec heads from GM. We're talking nothing short of 50 more hp!
The Saturday-Night Buildup car made a huge leap forward in performance at our most recent 11/42-mile, dirt-track oval race at Perris Auto Speedway in Perris, California.
Thanks to a set of GM Performance Parts Vortec heads (PN 12558060/see our Feb. '98 issue), a new camshaft from Comp Cams, new spark plug wires from Performance Distributors, and new race tires from McCreary, the car took on a whole new attitude. Actually, believe it or not, the complete head sells for less than the bare head (PN 12529093). Even if you didn't want the extra parts, you'd be better off purchasing complete heads and saving the valves, springs, and so fourth.
While we were more than very pleased with the performance of the stock crate engine, we wanted to bump it up a notch, similar to what a typical guy might do after a season of racing. The new parts were just what the doctor ordered.
We have done extensive before and after dyno testing at K&N Engineering's state-of-the-art chassis dyno to make sure we weren't skewed by seat-of-the-pants impressions. The new heads and cam were worth 45 hp at 5,250 rpm compared to the stock engine. This low-buck, rock-crusher-simple engine is now putting out 235 hp for about $2,600. Our original engine, complete with 1.6 rockers and shaved heads, put out 228 hp! And that's with about $500 worth of heads and cam-amazing.
We finally got the courage to lean out the Barry Grant 4412 two-barrel carburetor. We ended up going down three sizes to an 80 main jet. But then we noticed a jittery, erratic condition in the power curve above 4,000 rpm. K&N dyno operator James Psihramis suggested going up on the power valve size based on some testing done at the shop with a spec truck. We increased the power valve to a 35, and when all this jetting was done, the powerband was far smoother.
These numbers made us delirious. The scene at K&N's dyno reminded me of one of those infomercials-"I wouldn't have believed it if I hadn't seen it myself." It was truly a remarkable improvement for a very little amount of money and effort. So much for those hot dogs with all their fancy engines.
Did the car act differently at the track? Absolutely, 100 percent better. The engine was snappy (and we're still talking about a 9:1 compression ratio here) with a whole lot more power than it had at the previous race.
In our heat race, we flew through the pack to finish Third and transferred directly into the main event. We started the main in the 12th spot and ground our way up to Fourth Place with five laps remaining in the 30-lap race. Driver Bob Carpenter was just about to pass both the Second and Third Place cars to go into Second, when the caution came out.
The car was visibly faster than before and Carpenter even commented that his neck was getting strained from the cornering forces. While circulating around the track under caution, the car quit. We didn't know why until a day later when we discovered it had run out of gas! We had run only 20-lap mains in the past and didn't know we couldn't make it for 30 laps (there were a lot of cautions and even a red flag).
After the race, the car drew a crowd. One guy sneered that there was no way it had a crate motor in it. I told him I'd tear it down with him right there, and for every nonstock part he found (except for the solid lifters, Competition Cams camshaft, and Edelbrock intake manifold) I'd give him $1,000. The look on his face was great. "Are you serious?" he asked. "Damn straight," I told him. "It's those Vortec heads." When Circle Track first proposed using this engine, we thought there was no way it could run with the high-dollar race engines. But we have been happily surprised with the performance. Next season, we're shooting to win a race with this engine.
We like to arrive at the track...
We like to arrive at the track early enough to get a decent pit spot. The car is always ready to race off the trailer. There's no such thing as repairing the car before a race.
Readers who have been following...
Readers who have been following along with the GM Performance Parts crate motor test know that we upgraded after a couple of races to a Comp Cams camshaft that has .510-inch lift.
Another factor in our upgrade...
Another factor in our upgrade was the addition of solid lifters. We've never used solid lifters before and expected to be constantly annoyed by having to reset the valves. We didn't have to.
Yes, Virginia, we continued...
Yes, Virginia, we continued to use all the stock components in our crate engine. The heads have push-in studs. The rocker arms are stock. The valvesprings are stock. There's no porting, no shaving, no nothing. It's understandable that many don't believe we are getting that kind of performance.
One key to using Vortec heads...
One key to using Vortec heads is you need an intake manifold that not only fits the new bolt pattern but gives good performance. Edelbrock's new Performer RPM Vortec manifold (PN 7116) is a dual-plane, high-rise intake designed to make power in the 1,500- to 6,500-rpm range. It bolted right up and worked great.
Notice how our Phoenix Fire...
Notice how our Phoenix Fire Systems halon bottle is mounted within easy reach of driver Bob Carpenter. Here's a new one. He put his helmet on the rollbar next to the extinguisher. When he picked up the helmet, he accidentally bumped the button on the bottle and discharged the halon. Great! He didn't tell anyone, because he thought they might not let him race without a functioning extinguisher. Great! Luckily, there were no fires that week.
Here's another big switch...
Here's another big switch we made. We finally tossed our old retread track tires and went with real racing tires. These McCreary tires are a perfect blend of excellent traction and decent wear characteristics. It really made a big difference on traction. Of course, the forward momentum was better coming off the turns, but what we didn't expect (and were very happy to find) was the increased lateral traction. This meant we were able to go into the turns deeper and faster, and the tires held the car on line. As most people know, getting through the turns faster is the key to faster lap times.
The front tires have a different...
The front tires have a different tread pattern than the rear. Notice there are really no side-to-side grooves. The longitudinal grooves do all the work when the car is trying to go sideways in the turns.
The tech inspectors at Perris...
The tech inspectors at Perris Auto Speedway noticed a couple of tiny light bulbs hanging down under our dashboard. To prevent any shorting out, we taped them together. They were the bulbs from the gauges. Why didn't we just stick them back in? Too lazy.
We don't have a big crew of...
We don't have a big crew of guys working on the Saturday-Night Buildup car. It's just car owner Earl Carpenter, driver Bob Carpenter, sometime crewmember Scott Talkington, and fellow competitor Mike "Hubcap" Collins. Occasionally someone hangs out and helps us for an evening. Hey, don't be shy.
Spark plug changes became...
Spark plug changes became a ritual before the main event at each race. We were sure the car was rich, but because the 76 Products unleaded racing gas doesn't leave the same kind of easy-to-read deposits on the spark plugs as leaded racing gas does, we were afraid of going too lean so simply did nothing. Luckily, we figured out the right jetting at the dyno in just a few minutes.
Check out the firewall. It's...
Check out the firewall. It's splattered with engine oil. For some reason, the car suddenly decided to spit oil out of the filler tube. We guessed that one valve cover breather was simply not enough and will add a second one before the next race.
One of the best investments...
One of the best investments we ever made was a fresh-air system for our driver. Even though we race at night, the exertion and nerves of a race driver raises the body temperature. The cool, fresh flow of air to his face keeps him comfortable and allows for a more capable functioning brain. Calm and cool is the key.
Now this was weird! With about...
Now this was weird! With about seven laps to go in the main event, our driver noticed what he thought was the filter wrap coming loose and flipping up and over the roof of the car. In fact, it was the entire K&N Flow Control air filter! The stud broke off-probably because we've used the same one for four years. The filter was run over and knocked up to the top of the groove. We recovered it undamaged.
The McCreary tires really...
The McCreary tires really held up well in the 30-lap main event at Perris Auto Speedway. The track surface is a perfect combination of cushion and traction. These race tires made a big difference in corner speed. Check out the ding in this brand new Pete Paulsen Motorsports 10-hole wheel!
We've been experiencing a...
We've been experiencing a lot of flat tires lately and, after asking around, discovered we were running much lower tire pressures than most other racers at Perris Auto Speedway. We were running 15 in-lb on the inside tires and 18 in-lb on the outside tires (yes, we know a lot of people run more pressure in the right front tire, but we're not having any problems there, and we've always done it this way), but now we've bumped that up to 18 in-lb on the inside and 22 in-lb on the outside. We didn't get a flat at this race. We run tubes for what we feel is an extra margin of safety. A lot of people tell us to get rid of them, but we're convinced that running tubeless is riskier on a dirt car on which wheels get banged up pretty good every week. We are, however, considering getting some bead-lock wheels.
K&N has been really helpful...
K&N has been really helpful with testing the Saturday-Night Buildup car on its chassis dyno. We've learned a whole lot about the changes we've made, and we were even able to tune the Barry Grant carburetor a bit.
Here are two very different-looking...
Here are two very different-looking spark plugs out of the same engine. The one on the left is very black around the threads but still looks white on the porcelain. This confused us, and we left the car too rich for far too long before changing the jetting.