#TBT | A dual-engine Honda CRX and 10 other cool cars hit the dyno

[Editor's Note: This article originally appeared in the July 1997 issue of Grassroots Motorsports.]

At our last Dyno Day, we found an additional 15 horsepower trapped inside an MR2; this time, we released 24 extra horses from a V12 Jaguar. Major surgery? No, just a much-needed hour of dyno time.

After successfully hosting our first Dyno Day, Bill Davis and the Performance Dynamometer crew invited us back May 3 for a second one. The rules were still the same: for $50, each participant would get about an hour of time on Performance Oyno's Dynojet chassis dyno.

Besides the dyno tuning, a relaxed atmosphere was the rule of the day. Participants were observed running their cars on the dyno, as well as playing with our publisher's kid, drinking Slurpees, eating copious amounts of food, and actually smiling and having fun.

The Dynojet we used is a simple, yet effective tool. A roller, placed under the drive wheels of a car, measures real world horsepower and torque. A desktop computer receives this information, which interprets the data and spits out the numbers and graphs.

The testing itself is actually a pretty simple process: strap the car onto the dyno rack (looks like an alignment machine); do a part-throttle run to make sure everything is secure; check the tie-down straps; and then blast away, usually running hard from about 2500 rpm up to redline. When the car reaches the end of its run, the dyno operator lets off the gas and the dyno takes care of slowing everything down. About a second later, the horsepower curve is pro­jected onto the computer's screen. The computer also shows torque curves and wheel speed; the latter can be used to verify speedometers. 

Data on each car is saved on the computer's hard drive and can be compared to subsequent runs. All runs are corrected via the SAE's correction factor for temperature and air pressure, allowing fair and accurate data readings. Therefore, everyone compares apples to apples. The dyno is also NASCAR certified, the motorhead equivalent of being deemed kosher.

Dyno day participants were treated to a tasty lunch provided by Polar Power Industries. Here a group of power-hungry folks feed their hunger for food while J.G.(foreground) does his best to look surly.

We inadvertently scheduled our Dyno Day for the same weekend as two major SCCA events, A Divisional Solo II in Atlanta and a National/ECR Enduro at Daytona International. However, we still managed to attract an interesting and varied group of people and their cars. 

The first car on the dyno was also one of the most interesting: a twin-engined 1984 CRX. "The car was built in' 84-'85 by Racing Beat in Anaheim, Calif., and articles were run in Car and Driver magazine," current owner Joe Dunlop explains. "I found it at Zephyrhills auto auction and I knew what it was."

Unlike most early CRXs, Joe's is powered by a pair of 1.8-liter Accord engines- one powers the front wheels and another, located in the trunk area, propels the back wheels. The engines are basically stock, although their mounting arrangements are a bit unusual. Each engine, running through its own automatic transmission, put 84 to 8'5 horsepower to the ground, which put to rest any of Joe's fears that one engine was stronger than the other. 

"It's the ultimate sleeper," Joe says about the CRX. "The car will not spin tires from rest on dry or wet." At the drag strip, the car has posted a 14.5-second E.T. with a 95 mph trap speed.

Next up on the dyno was Robert Belvoir and his MR2, our first repeat customer. When Robert arrived at our first Dyno Day, his car was making only 98 hp and exhibited a jagged power curve. Playing with the timing brought the car up to 113 hp, and Robert left as a happy camper. Since then he has leaned out the carbs a bit, tweaked the ignition timing a bit more, and installed some Ignition Equipment wires. By the end of the second Dyno Day, the MR2 was producing 132 hp @ 7500 rpm. "The engine was rebuilt, but no one knew where to set the ignition timing," Robert explained. "Apparently ignition timing determines horsepower, and carburetion determines drivability." 

The next participant was also a repeat offender. At our last Dyno Day, Ken LaRoe found his prototype Polar Power cold air induction kit worked so well on his I 994 Miata that he has started selling them to the general public. He is now developing a similar kit for the early Miata and was on hand to play with an early run model. "The system increased rear wheel horsepower by IO on an 1800 '94 Miata," he said. "The 1990 1600cc, however. only increased four horsepower. I believe the trap-door type air flow meter on the 1600cc model is restrictive to the point of limiting power despite the cold air system. I may experiment further with a replacement adjustable computer which eliminates the factory airflow meter."

Dyno time also went to several people who were mainly interested in getting baseline numbers before carrying out later mods. Ken LaRoe's dad, Gene LaRoe, showed up with a 1972 Datsun 510 wagon, original down to the factory green paint and stock 1600cc engine. Of note to enthusiasts are the factory tach and twin SU carbs mounted on an SSS intake. The car actually belongs to Gene's other son, who purchased it from the heirs of a now-deceased lady who bought the car new. "It only has 57,000 original miles, original paint and stock interior," Gene told us. So, did this piece of Nissan engineering blow everyone away with a zillion horsepower? Um, no, but it did crank out a respectable 61 hp@ 5250 rpm.

Bill Berman, the man behind Daytona MIG welders, brought his 1964 Morris Mini Minor. Its 850cc A-series engine singing at full song produced 25 hp @ 5250 rpm and 32 ft.-lbs. of torque@ 2750 rpm. "The Mini is quick in city traffic," Bill explains, "but suffers from a lack of top end on the highway." He plans to swap in a 1275cc engine to give the Mini a little more pep.

Another driver interested in just getting some baseline num­bers was Chanele Brothers. Her dad, Ron, had recently picked up this 1987 RX-7 Turbo II for her, and they were interested I charting its performance. Even though it’s a stock piece with 100,000 miles, Chanele said “I’m happy with this car.”

After her car was done, her dad wheeled his 1978 Jaguar EJS-C onto the dyno. With 5.4 liters of very modified VI 2 Jag power exiting through a custom side exhaust, it sounded as if a WWII fighter was readying for takeoff. Leaning out the fuel mixture about 10 percent (allowable thanks to an aftermarket engine management system) gave Ron an additional 24 horsepower at the wheels.

One of the more unusual-looking cars at Dyno Day was Keith Parker's GTI Corvette—weird-looking because the bodywork wasn't installed. Still, the blue beast pulled out 376 hp, thanks to a combination of 334 cubic inches, Manley six inch rods, Lazer camshaft, Goodwrench aluminum heads and more. This is the engine Keith plans on using for his return to Regional Racing; a real trick mill is in the works for National Racing.

The import drag scene has exploded in Central Florida, and 1988 CRX Si driver Dan Schulman was our 1 /4-mile rep for the day. His Honda reads like a wish list for CRX owners: Bullfrog cam, balanced and blueprinted injectors, Jacobs ignition, RS Akimoto air intake, DC header, JG throttle body and GReddy exhaust system among other hot rod Honda parts. On slicks, the car has run mid-14s at the 1 /4-mile (about as fast as a new Mustang Cobra or M3).

Dan mainly wanted to play around with his ignition timing and spark plug gaps. His best run, 121.8 hp @ 7000 rpm, was achieved with 40 degrees of total advance and .042-in. spark plug gap. He found that opening the spark plug gap up to .056-in. cost about three horsepower, while retarding the ignition to 35 degrees of total advance also cost some power. Dan wants to play with his adjustable cam sprockets next time on the dyno.

Local autocrosser, student and motel manager Meno Akarjalian showed up with his C Street Prepared 1986 RX-7 and had several ideas we wanted to try. Before making any changes, he recorded a baseline run of 131 hp @ 6500 rpm. For the next run, he removed the stock air filter cover and installed a modified one–he simply cut the center of the cover, hoping to increase the airflow into the engine. Well, it seems his idea worked: the next run showed 135 hp & 6500 rpm and a max of 141 hp @ 7000 rpm.

Local autocrosser Meno Akarjalian found that replacing his air filter cover with one he'd cut the center section out of gave his RX-7 more horsepower at the rear wheels. Running with the Auxiliary Port Valves open did not yield any sizeable gain.

Next, he wanted to see if running with the Auxiliary Port Valves open would help. “The APV opens two normally closed ports in the six-port rotary engine," he explained. 'The ports are closed for better fuel economy and low-end torque and opened with exhaust back pressure during high-performance driving.

"With the Auxiliary Port Valves tie-wrapped open and the open air filter cover installed, horsepower at 6500 dropped to 133.6 and at 7000 rpm horsepower dropped to 140. However, horsepower was greater at the mid-5000-rpm range with the APVs open than with them closed."

Around six that evening, we loaded the final car onto the dyno—WiIfred Nelson Jr.'s 1991 Plymouth Acclaim. Not exactly a car that screams performance, and that's the idea. "Great sleeper," he calls it. Wil has a ton of performance parts on the way for the car's Mitsubishi-built three-liter engine, so on this day he was mainly interested in some baseline numbers. A harsh shift kit made the car a bit unstable on the dyno, but he still clocked 130 hp @ 6400 rpm and a stout 196 ft.-lbs. of torque at 2400 rpm. Once Wil gets his transmission sorted and his parts from Forward Motion and Lambros Racing arrive, we hope to retest the car.

Most Dyno Day participants stayed all day, watching and learning from other people's dyno runs. Performance Dynamometer's shop has a nice viewing area away from the smoke and the noise.

Pulling off dyno day would not be possible without the work and help of others. Our thanks to Performance Dynamometers owner Bill Davis and his staff—Dave Cutter, Mark Davis, Kevin Helton and Joe Piorkowski—for remaining cheerful all day, even though they ran 11 cars through their shop during the event. If you would like to do some dyno testing on your own time, call them at (904) 427-0390. Remember these words: the dyno doesn't lie.

Ignition Equipment (phone 941-3598454), sponsor of the event, also deserves a public thank you. After the event, we sampled some of their wires on our Project CRX, and while we only picked up two extra horsepower, the curve became much, much smoother. Lunch was supplied by Polar Power Industries (phone 352-3142100), the company that produces the cold air induction kit that added I O horsepower to the 1994 Miata at our last dyno day.

Look for Performance Dynamometer to host another GRM Dyno Day, probably in mid-November.

Comments

Displaying 1-10 of 20 commentsView all comments on the GRM forums

You'll need to log in to post.