Grassroots Motorsports

Dyno Daze May 3, 2000

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This past weekend we did some dyno testing at Engineered Performance in Smryna, Ga. (http://www.engineered.net). First off, we need to mention that owner Ed Senf has put together a great crew that was great to work with: Glenn Affourtit, operations manager; Chuck Manning, fabricator; Aaron Ha, turbo guy; Damon Waguespack, Honda tech; Ramona Burkett, Nissan tech; and Aaron Montell, tuning apprentice. Chuck spent most of the day with us, and all we can say is that he rocks--nice guy and an excellent fabricator.

Engineered Performance is a rather large shop located on the north side of Atlanta, just a few miles from the I-75 and I-285 interchange. What makes their shop extremely interesting was the wide variety of cars present during our visit: a Jaguar sedan awaiting a frame-off restoration; an E30-chassis BMW M3 BMW CCA Club Race car; a first-gen Toyota MR2 getting a supercharger install; a Mitsubishi Mirage that was receiving a 276-horsepower, Japanese-spec Lancer engine; a pair of extremely clean Honda CRXs; a few TR7s stuck in suspended animation; and a Datsun Z car that was in for some Electromotive tuning.

Besides the Dynojet chassis dyno and their custom work, they also do routine maintenance and work on street cars. They also have a Crosley Super sitting out back.

Many customer cars also showed up during our testing day, including several turbocharged early Z cars, with Eric Chapman's turbo 240Z posting 376 rear wheel horsepower on the dyno. (Eric also helped us work on the Miata, making him a good egg.) A fleet of Hondas and RX-7s also showed up, including the supercharged, four-door Integra GS-R featured on the Engineered Performance Web page.

Our first item to be dynoed on our Miata was a set of NGK spark plug wires. Our original wires were pretty junky, as Miatas are notoriously hard on spark plug wires. They were brittle and easily came off (sometimes too easily, like while we were driving the car).

Well, the dyno showed that the NGK wires performed about the same as the old ones, but at least they won't pop off the coil pack as often.

A popular Miata trick involves bumping up the initial ignition timing from 10 degrees to 14 degrees. This free modification gave us a few more foot-pounds of torque below 5000 rpm, while slightly increasing horsepower throughout the rpm range.

Next up on our list was a Jackson Racing Cold Air Intake (http://www.jacksonracing.com). The Jackson intake replaces the entire, convoluted stock system with a one-piece air scoop. Where the stock setup inhales through the back of the engine compartment, the Jackson intake grabs fresh air through the mouth of the car.

Installing the intake was no big deal, although there is a spacer that must be placed just above the thermostat housing. To save on time, we installed this piece before heading off to the dyno. The hood prop rod must also be repositioned, and this too was done before going to the dyno.

The air bag sensor must also be temporarily removed during the install, but it too is not a problem. Before buttoning up everything, we "port matched" the plastic Jackson intake to our air flow meter.

Within an hour we had the new intake installed and were ready to go.

Our max horsepower increased from 92.1 to 96.5, with max torque rising from 85.6 lb.-ft. to 89.7 lb.-ft. What the numbers don't show is a nice increase of botton-end torque. Like Ed pointed out, the gains in maximum torque and horsepower are for the magazine articles; the increases in low-end torque are what makes a difference in real-world driving. Plus, in theory, the Jackson piece will make a bigger difference at speed, as the system will allow our engine to ingest nice, cool air. Look for before-and-after 0-60 times to be posted soon.

Next we ditched the stock exhaust system for one from Jackson Racing: header, high-flow catalytic converter and complete exhaust system.

The exhaust system ($499.00) features stainless steel construction, a high-flow muffler and excellent construction. Installation was as simple as removing the old one and hanging the new one. The Jackson system fit as designed and features welds that are probably too nice for something that will never been seen. Like the factory system, the Jackson piece features a center resonator.

We also replaced our catalytic converter with a new, high-flow model. Our stock, 79,000-mile cat wasn't clogged (yet), but we did manage to break some of its studs while removing the exhaust system. Replacing the cat along with the exhaust is probably a smart move, as a fresh cat will help your engine breathe better while keeping our precious atmosphere clean. Plus, as we found, the studs on the stock one like to snap. The Jackson Racing cat is ceramic coated for good looks and long life. They retail for $179.95--significantly less than the stock part.

Our final mod for the day was a Jackson Racing header--now we could see how their whole intake and exhaust package works together. This tuned, 4-2-1 header features CNC-machined flanges and a ceramic coating. It perfectly mated to our new cat, too.

With everything on and buttoned up, we were now making a max of 102.9 horsepower and 92.4 ft./lbs. of torque--a 12-percent gain from our original numbers.

While not measured on the dyno, throttle response is way better than before--tip-in acceleration is better, and the car is simply more fun to drive. The exhaust note is not that much louder than stock, although after seven hours on the highway, any Miata starts to get uncomfortable.

During our testing, it was interesting to see how the exhaust and intake gave us increases at both ends of the rpm range, but left a dip in the center; the header filled in that dip. It's almost like they designed these parts to work together as a system.

Once we get all of our dyno numbers back from Engineered Performance, we'll post them here. Plus, after a week or so with our new mods, we'll probably have lots more info (and impressions) to share with you.

During our Atlanta weekend we did encounter one semi-major problem, which now needs to be addressed: the throw-out bearing in our clutch has passed on. Later this week the car heads over to Daytona Beach's RML Automotive (http://www.rmlautomotive.com) for a new one. While we're in there, we'll replace the clutch and install and aluminum flywheel. The car should be back on the road in time for this weekend's TSD rally. (Did someone say rally??)

Check back soon for more updates on this car, and for some photos from the day, click here: http://www.engineered.net/miata.htm

Before ending this segment, we also need to thank Randy Stocker (http://www.solomiata.com) and Rob Ebersol (http:www.ebersol.com/RR) for helping out with moral support while at the dyno. If you're looking to buy any Jackson Racing parts, please check out Moss Motors' home page (http://www.mossmotors.com/miata/catalog/tblofcontents/onlinecatalog.html). For good, general Miata info, don't forget to visit Miata.net (http://www.miata.net) and the Miata Forum (http://www.miataforum.com).

Sometimes it's nice when performance modifications actually make a real-world difference. Before installing our Jackson Racing header, intake, exhaust and high-flow cat, our Miata took 8.9 seconds to accelerate from zero to 60 mph. After our first round of mods, the car now needs only 8.0 seconds to accomplish the same feat--and this was with a slipping clutch.

Our Miata also now has a seven-pound aluminum flywheel (stock is 18 pounds) and fresh Jackson Racing Stage I organic clutch. So far we have only put about 50 miles on the combo, but around town, our butt-dyno says the engine pulls much harder than before. The clutch engages as soon as your foot comes off the floor, however, which takes about five minutes to get used to.

Once everything is broken in, we'll run some acceleration numbers and compare them to our earlier ones. 

Pondering Power Jul 3, 2000

With its new aluminum flywheel and host of Jackson Racing parts (http://www.jacksonracing.com), our Miata is just humming along. Once the temperatures get back into the bearable range, we'll run another set of 0-60 times. (The last set of runs were done on an 80-degree day; lately it has been about 95 degrees outside.)

On a different note, Pettit Racing's Cameron Worth (http://www.pettitracing.com) really, really wants us to turbocharge the car. Doing so would definitely mean having to upgrade the differential to a later Torsen unit, but it is a tempting option. We'll keep you posted, and if you have any feelings about us going the forced-induction route, let us know.

We were hoping to keep the car legal for SCCA's C Street Prepared class, but that idea is quickly going away. Plus we recently received Dealer Alternative's (http://www.dlralt.com) Flyin' Miata big brake kit to test and evaluate, more equipment that's not CSP-legal. We are also taking another look at our tire choice. We originally went with the Michelin Pilot SX MXX3 since it's one of the best high-performance tires available. Unfortunately, they're also on the heavy side--that's fine if you have the torque of a Camaro or Porsche 911, but a 100-horsepower Miata doesn't really have the muscle to spin them with authority.

We recently had a good, rebuildable cylinder head dropped off at Engineered Performance (http://www.engineered.net) for a little machine work. They will be sending it to their machine shop, Clark Engine Works (phone 770-590-5226), for a little R&R--little of this and a little of that. Our goal is to strengthen the car's performance in the 4000 to 7000 rpm range. A set of Unorthodox Racing (http://www.unorthodoxracing.com) adjustable cam gears will also be installed.

The plan is to install the rebuilt head in time so we can tune the car at our upcoming Dyno Day. Look for Part I of the project in the October issue. 

Big brakes Mean Big Wheels Aug 25, 2000

Since our Miata is about to receive a Dealer Alternative Flyin' Miata big-brake kit, we needed some appropriate wheels to clear them. The 15x7-inch Kosei K1 Racing wheels that we're using on the street should clear the big brakes, but the stock 14-inch Miata wheels that we're using for racing won't work. We again wanted something light and easy on the budget, so we ordered up a set of 11.5-pound, 15x6.5-inch Rota Circuit 8 wheels from Atlanta's RSpeed. Another cool feature is their $135 list price.

By the way, even before installation, the Dealer Alternative brakes are impressive, with 11-inch slotted rotors and aluminum Wilwood calipers. A billet, anodized bracket is included to mount the calipers to the stock Miata hubs, keeping this a bolt-on project. Look for before-and-after braking numbers once we have them.

We have also received word from Engineered Performance that our cylinder head is done and looks sweet. We hope to have it installed and dyno tested soon. 

Head Dec 18, 2000

Our new cylinder head is done and has been installed. Hats off to Engineered Performance and Clark Engine Works for coming up with a setup that makes more power. We're now making 112.8 horsepower at the rear wheels--20 more than the car made when we first got it. Torque is up, too.

The new head features swirl-polished, stainless-steel valves, lots of porting and polishing as well as a light shave. It makes power from 2000 rpm up to redline, so it's totally streetable. The car also idles fine and runs on pump gas. While the head was off, we replaced many engine parts--waterpump, timing belt, idler pulley, coolant hoses and so on--essentially renewing the entire engine.

We just did our first oil change since installing the new head, so we're ready to go do some 0-60 runs. The car's sump is now full of 5W-30 Red Line synthetic oil.

The complete story on the engine mods and tuning will be in the February issue, yet we're already looking for ways to make more power. Hmmmmmm......

On another note, we have been running the Nitto NT555R Extreme Drag radials on the street since July. After a few thousand miles, we have found them to be an excellent dual-purpose tire: grippier than a normal street tire but longer lasting than a normal race tire. As a bonus, they're quiet and have a wide, usable slip angle. We are running a 205/55-14 size on the stock 14x5.5-inch Miata wheels. Soon we'll be going to mount a set of 195/50-15 Toyo Proxes T1-S tires on 15x6.5-inch Rota Circuit 8 wheels. 

Wax on/Wax off Feb 28, 2001

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While work has slowed down on our Miata, don't think this car is being neglected--we have just been gathering parts and info. We're still happy with our Koni Sport shock absorbers, but the entire suspension is about to receive an entire makeover with parts from Open Mind (http://www.opmd.com) and Racing Beat (http://racingbeat.com). Some fresh original-equipment parts were also ordered from Performance Buyers Club (http://www.performancebuyers.com). We'll also have some brake upgrade info heading your way.

We still feel we can increase our horsepower without going to the forced-induction route, and we'll soon be writing about our Flyin' Miata/Link ECU upgrade.

The car was starting to look a little dingy, so last weekend it received a day of beauty, consisting of the Meguiars four-step program: wash, cleaner, polish and protectant. Completing the entire process took several hours, but now the car looks great. (It's white again.) We simply followed the Paint Car Prescription from the Meguiars Web site (http://www.meguiars.com).

Speaking of cosmetics, a Miata R factory front spoiler was also ordered from Performance Buyers Club. Currently it's listed as a Web special for only $139.95.

While this car has taken a slight hiatus from the magazine, it will soon be back with a vengeance. 

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