RX-7 Recommendations

Information and Recommendations

The following suggestions are intended to keep your car out of the shop and on your favorite road, by Pettit Racing

It is fact, that mechanical things will function as designed for a period of time, then preventive maintenance must be done, if neglected one can expect less than optimum performance or worse, a failure may occur.


If you trust your life to a mechanical thing it should be mechanically sound (i.e., up to date on maintenance, clean fluids and filters, brakes and suspension operational and working properly, good tires etc) Obviously, if something is wrong it could be dangerous and continued use under these conditions will usually cause more damage and expense when repairs are done.

If your vehicle is not running properly, or maintenance is not up to date or, or your just not sure, please see our recommendations at bottom of page.

BEFORE YOU UPGRADE As well, before upgrades are done, everything above applies including both turbos must be working properly and producing the correct boost levels. Upgrading a poorly maintained vehicle with inconsistent or low boost will not produce the expected results and could even cause expensive engine damage.

Always install upgrades in logical stages and install only one upgrade at a time. This allows you to evaluate changes in vehicle dynamics from each modification and if any problems arise, you only have to go back one step to find the cause.


#1. Always keep up with routine maintenance schedules as outlined in the owner’s manual.

#2. Upgrade chassis and engine grounding points with our FREE KIT. Just call and ask for one. Do it now!!!

#3. Replace cooling system plastic air separator (A.S.T.), well known for splitting in half with no warning causing massive coolant loss and overheating. Our very popular aluminum upgrade units are always in stock.

#4. Replace that dirty fuel filter!!! Countless premature engine failures are caused by a dirty fuel filters. Don’t let this happen to you. Poor fuel quality also contributes to engine failures ALWAYS USE PREMIUM FUEL!!!

#5. Install a turbo boost gauge! This is the only way to be sure the turbos are working properly. We produce several Kits. All are easy to install, and come pre‑wired with detailed instructions.

#6.Use fuel lubricant. This has been proven to extend engine life at least 30%. For more info Check out Protek-R at http://www.pettitracing.com/protek-r/

#7. Get a Fire Extinguisher!! A must have for any vehicle…that way you will never need it! Our auto fire extinguisher installs in minutes and it looks cool, too.

#8 Most RX7’s benefit from cooler operating temperatures our 185f fan switch is a direct replacement for the original 210f part and as they get older its common to see 225f before the fans kick. As we all know cooler running improves longevity for the engine as well as all under hood components.

#9 Whenever possible open the oven door (hood) this stops the baking process and improves longevity for all under hood components. We have many customers that have proven this works; their cars continue to perform flawlessly year after year.


We always use premium quality fuel and we always mix Protek-R with every tank. 93-octane minimum for boost up to 12 psi. For higher boost levels, we recommend mixing a couple gallons of race fuel with 1/3 -½ tank of 93, this can help prevent detonation. Check out Protek-R at http://www.pettitracing.com/protek-r/

Take your time and always install upgrades in logical stages and only one at a time, this allows you to evaluate changes in vehicle dynamics made by each modification, and if any problems arise, you only have to go back one step to find the cause.

We believe having reliable performance is paramount; it is the best way to routinely get fun and excitement from your

How should I care for my RX-7?

The following was posted to the RX-7 list by Jeff Witzer. It was titled “Lessons Learned”…

“In the struggle to solve problems with my car, I have learned a few things that I’d like to pass on. This is prompted by last weekend’s fix of some engine performance problems that had taken much of the fun out of driving.

There are several people on the list with much more intimate knowledge of our cars, but this might be a good collection of advice for the novice who whats to take good care of their 3rd gen. I’ve got well over 80,000 miles on my car and it still drives hard and produces a solid 14.5 pounds of boost with no complaints. Cam Worth at Pettit has remarked several times that he can’t believe how well it still runs. He asked me to pass these on…

Warm the car up before driving hard

Start the car and immediately poke the throttle to prompt the kick-down. (Pettit actually recommends turning it off for a couple of seconds immediately after it catches to allow freshly pumped oil to seep into the bearings while they’re loose, then restarting.) A lot of wear occurs during that 30 seconds or so at 3,000 RPM. It does this to warm the cat to operating temp sooner, but at the expense of your bearings. Within a minute, start driving. Warm up the car under light load, not sitting idling in your garage. Wait until the temp gauge shows normal operating temp before going above 4,000 RPM or above 5 lbs boost (see boost gauge below).

Let the car cool down after driving

Allow at least two minutes of cool down at idle after normal highway driving or after short bursts of full throttle. Allow up to 5 minutes after extended use of high boost. This allows cooling oil and water to reach the hot bearings in the turbo. Neglecting this will cause the oil there to coke into solids, accelerating wear. Always allow at least 30 seconds of cool down after using boost. I use and recommend a turbo timer which lets the car run for a preset time after the key is turned off and removed. I’ve heard rumors of list members getting in trouble for leaving their car running while unattended, so YMMV.

Oil and Filter changes every 3,000 miles (max)

This should be obvious. General consensus (and my practice) dictates 20W50 and OEM filters (new crush ring each time). This is for summer driving (which is all we get in Tampa). Some recommend synthetics, which can be run in rotaries, but may leave deposits as oil is routinely burned. For non-racing applications, stick to dino juice. I also use Pettit’s Protek-R fuel lubricant, but some on the list have argued against it’s claims… again, YMMV.

Rotate tires every 6,000 miles

You wouldn’t believe how much this extends tire life. Of course this only applies if you’ve got the same tire sizes all around. I also get my alignment checked at this interval, but normal driving probably doesn’t demand this.

Spark plug and fuel filter changes every 15,000 miles

You wouldn’t believe the crud that the fuel filter grabs. Remember, the 3rd gen uses Miata filters, but flows twice as much fuel. New plugs have been the fix to most of my hesitation problems. The manual says 30,000 miles but I haven’t found anyone who has gotten that much out of stock plugs. For normal applications, stock plugs are best.

Replace oxygen sensor around 60,000 miles

This is what has been biting me over the past few months. Major 3000 RPM hesitation, stumbling over 5000 RPM, loss of power if held at constant RPM with light throttle, and loss of fuel economy. Thanks to Cam at Pettit for this cheap fix. I was convinced my fuel injectors had clogged or finally given out (major $$, major effort).

Use synthetics in the gearbox and differential

After the car is broken in, replace these fluids with synthetics to improve shift feel, quite gearbox whine, and reduce friction and wear.

Install a boost gauge

This will be the best diagnostic tool you’ll have. It’s best to determine if that loss of power can be blamed on a loss of boost (due to the common splitting, cracking, or loosening of vacuum lines) before going through the expense of tracing fuel and electrical problems.

Be wary of dealer service departments

Since most dealerships service few 3rd gens, they tend to botch most non-routine procedures. Oil changes, spark plugs, fuel filters, etc they seem to do fine, but recalls (especially the fuel line recall) seem to be impossible for them. There are caveats, of course. If you don’t see a third gen in a bay or two in the garage, I’d worry. Find a specialist you can trust.

Take upgrades slowly

Upgrade your car one step at a time. This way, if one of the mods is faulty or the car isn’t prepared for it, you’ll know which mod is to blame. Usually it’s best to follow this order: cat-back exhaust, intake system, intercooler, ECU, main cat replacement, pre-cat replacement. Make sure your ECU can handle the increase in boost that the following cat replacements will generate. Talk to specialists before removing cats to ensure your engine is ready.

Check tire pressure and wear every car wash (weekly)

The 3rd gen is quite touchy when it comes to tires. Don’t overlook these. Detailing your car is another subject…

All other normal car checks apply

Follow normal procedures for everything else. Take note of new noises or changes in performance and handling seriously.

Good luck and have fun!”

Spark Plugs

Stock Spark Plugs for the RX7 FD are manufactured by NGK and seem to work well. The Platinum type (P = platinum) seem to deliver good performance for a few thousand miles more than non platinum also the higher # is cooler.

BUR7EQP for the lead or lower and BUR9EQP for trail or top.

The original (factory) setup is to use NGK BUR7EQP in the two leading (lower) spark plug positions hotter plug is used here solely to improve emissions and NGK BUR9EQP in the two trailing (top) spots. Since the leading plugs do 90% of the work we have noticed that the life expectancy for the trailing plugs is usually twice that of the leading. For optimum performance with average driver we recommend replacing the leading plugs around 12,000 miles and the trail every other time, harder driving will reduce plug life.

For performance and hard driving, it is believed that colder plugs will last longer and reduce the chance of detonation. Often the colder trailing plugs are used in both trail and lead.

Engines running higher boost levels usually require plugs  with a tighter gap than the stock plugs, this is because higher chamber pressures increase the resistance across the plug gap demanding  more output energy from the ignition system to jump the gap, at a certain point of  high boost or worn plugs or both,  misfiring will occur. Most 3rd gens will run great with the stock plugs even at 12 pis boost, provided everything is working properly.

Ignition System

Primary ignition harness (coil wire harness)

As delivered the RX7 FD have two configurations for routing of the primary ignition harness, one (the most common) routes the harness between the secondary output towers of the leading coil. The other has it routed along the base of the coil bracket keeping max separation between the primary and secondary ignition. The latter routing seems to be the most reliable. The original equip coil harness was a shielded cable with a connection to ground at the coil mount nut, the replacement updated coil harness had this eliminated because as plugs and wires weakened spark would randomly jump to the grounded shield in the coil harness, after this happens once, a carbon track or path is formed and subsequent spark jumps become easier and easier eventually causing the lead ignition to completely shut down, but since the trailing ignition is still firing there is no obvious miss fire, just gradual power loss due to retarded spark and elevated engine and temperatures  higher exhaust temps.

Secondary ignition wires (plug wires)

Another problem we often see is loose plug wires at the coils, this can be caused by either accidentally loosening the wires or improper installations of ignition wires. They are designed to seal out moisture and are commonly installed by just pushing them into place, as they are seating a small amount of air gets trapped or even slightly compressed, thus as engine heat expands this compressed air it can push the wire back loosening the connection. This can result in arcing and damage to the system. When installing new wires be sure to burp the air from the boots as they seat.

Ignition Facts, in general, an ignition coil is like an electro magnet, it is continually attracting ferrous (conductive) material from the atmosphere to its surface eventually creating a path of conductive material to ground. whenever servicing the ignition system be sure to clean the coils.