The Guide to Performance and Longevity
The Guide although primarily intended to help RX7 FD owners enjoy an optimum balance of performance and longevity, can be applied to all rotary engines, piston engines and most mechanical devices where applicable. The Guide is a work in progress with mistakes, errors and omissions, please feel free to offer corrections and input. please know that the Pettit team & staff as well as anyone who may use & benefit from the information are thankful and greatly appreciate the time and effort from all contributors.
The Legendary RX7 FD
When production started in 1991, who would have thought that after more than 2 decades the RX7 FD would still provide a driving experience superior to many new world class machines. No doubt the sleek & sexy aerodynamic shape with silk smooth turbo rotary power helped create its legendary status as one of the most sought after sports cars on the planet. Sleek, powerful and deceptively fast the RX7 FD delivers speed and excitement with every drive.
Don't let fun become fatality It is a 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 device it should be mechanically sound and up to date on maintenance, clean fluids, filters, brakes, suspension and tires all good and working properly. Obviously, if something is wrong continued use will usually cause more damage and added expense for repairs. With any vehicle, suspension, brakes and fuel system problems can be extremely dangerous and should be corrected without delay. don't let fun become fatality.
Safety First: Get a Fire Extinguisher!!
A must have for any and every vehicle, somewhere it’s written, “If you have it you won’t need it”, this is very good when it comes to Fire Extinguishers!
Our Fire Gone Extinguishers use the latest fire suppression technology to quickly extinguish nearly all types of fires. Makes a great gift and is truly a must have item for every vehicle! “Safety First”
Basic Recommendations Always keep up with scheduled maintenance routines as outlined in the owner’s manual.
Upgrade chassis and engine ground points with our FREE KIT. Just call and ask for one.
We recommend a minimum 93 octane gasoline for all turbo or supercharged rotary engines and nearly everywhere it will contain 10% or more ethanol. Ethanol is basically alcohol great for drinking* and cleaning but probably not the best thing for engines especially rotary engines, all the more reason to premix fuel lubricant. Also with turbo rotaries just one tank of low-octane fuel can cause an instance of detonation and just one instance can compromise an apex or compression seal.
Low octane and poor quality fuel is a serious problem for turbo rotaries, unfortunately there is no simple method for testing octane and you never know if the fuel was bad until it is too late. We recommend always buying fuel from Company managed fuel stations.
FYI, on newer model cars the computer instantly adjust the timing and trims the fuel delivery compensating for bad fuel and variations in ethanol content. A bad tank of fuel in a newer car will make it a little sluggish until it sees good fuel, then the management system restores power.
Fuel Lubricant (premix)
If we expect our rotary engines to deliver top performance year after year, it is clearly evident that extra lubricant must be added to the fuel. Back in the mid 80’s we developed Protek-R fuel lubricant for our racing efforts and it was first released for sale in 1990. Since then, 30 years and counting our customers around the world enjoy reduced friction & wear as well as added performance & longevity. There is no doubt Protek-R had a major role in all our race victories, 5 Championships, over 50 SCCA national race wins, many top finishes in professional endurance racing like ALMS & the Rolex 24 hr races. as well as providing the added performance and longevity needed to win the 1998 GT-2 Road Race Championship. From the Rolex 24 at Daytona to 6 Hrs at the Glen we ran the same engine, nearly 130 hrs of racing. Our piston engines also get Protek-R premixed in the gasoline, many folks disagree but think about this, diesel piston engines may run a million miles, gas piston engines never get close, both use nearly the same parts and materials but diesels have 3 times more compression, more stress and loads etc. so why is it they last the longest…………diesel fuel is oil!! There is no doubt using fuel lube in gas piston engines will more than double its longevity.
Countless premature engine failures are caused by dirty fuel filters; don’t let this happen to you.
Install a turbo boost gauge! This is the only way to be sure the turbos are working properly.
The oven door
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.
Before you upgrade:
Before upgrading or adding more upgrades, scheduled maintenance and all the common issues should be updated or corrected first. Upgrading a poorly maintained vehicle with inconsistent performance, drivability problems or any boost issues will not produce the expected results and could even cause expensive engine damage. We often see poorly running FD’s with several upgrades that were installed to fix drivability and/or performance problems, typically if it is not running right, upgrades don’t help.
Every FD can perform beyond expectation in nearly stock form, always add upgrades for improvements, not to correct drivability or performance problems.
Since there are countless aftermarket parts and upgrades available for FD’s, possibly more than any other car, driving style, goals and budgets usually determine how the project progresses.
For DIY, we recommend installing upgrades in logical stages and just one at a time. This allows you to evaluate changes in vehicle dynamics from each modification, then if any problems arise, you only have to go one step back to find the cause.
Ongoing issues / problems
Nearly any RX7 FD can be setup to deliver a balance of performance and longevity beyond expectation delivering years of reliable driving enjoyment. To achieve this only requires learning some basic techniques to keep minor issues from becoming major problems and get a few simple updates and correct some commonly overlooked details.
This is especially important for FD’s with a history of problems that dealers and various shops either didn’t help or made worse.
Most common problems listed by importance & frequency
1 Cooling system, Air Separator, high operating temps & overheating
2 Oil Metering System, inadequate lubrication & compression seal failures
3 Air box failure: Dirt & abrasives in, engine wear accelerated
4 Ignition System, wires, coils & plugs
5 Sequential Turbo System testing, fixes & calibration
6 Problem solving with minimum boost set
7 More boost
8 Intercooler Efficiency & ICD losses
9 Thermal Management & radiant heat control are you wasting horsepower?
10 Common items / procedures
1 Cooling System Information and Recommendations
The first priority for RX 7 FD’s & nearly all liquid cooled engines is to have proper and efficient cooling. This is essential for consistent top performance, many years of longevity and driving enjoyment.
Cooling System Facts
It is a well known industry fact that cooler operating temperatures usually provide the best performance and longevity for any vehicle as well as all under hood components. On the US spec RX7 FD the cooling fan thermo switch and thermostat are factory set to maintain a minimum operating temperature of 92C / 197.6 F but with age, use and heat cycles these parts slowly degrade requiring higher and higher temperatures to open the thermostat and trigger the fans, as a result it is not uncommon to see temperatures of 104C / 220F and higher. Another commonly overlooked fact is that the engine temperature gauge is nonlinear and displays a normal reading from 71C / 160F all the way up to 113C / 235F, manufactures do this to avoid complaints and questions about gauge variations from driving conditions and weather changes.
Cause and Effect
When a leak occurs and the coolant level drops just a couple of inches, the temp gauge sensor is no longer immersed in coolant and since the leak depressurizes the system, the boiling coolant at 100C / 212F causes the gauge to display a normal reading even though the engine is getting hotter and hotter,
Rotary engines suffer the most of any engines when overheated. The brunt of heat is concentrated in the combustion area (from spark plugs to the exhaust port) super heating the aluminum rotor housing, this usually results in rotor housing shrinkage and coolant seal failure, this is also detrimental to all the accessories on the engine. We have actually seen engines run with no coolant until the aluminum around the spark plugs and exhaust port melts away.
Most coolant leaks usually start out small and go unnoticed until they are dripping on the ground or your engine is overheating.Coolant leaks can occur if any of the following items fail:
- Air Separator Tank, thermostat & fan switch
- Engine internal coolant seals
- Radiator leaks
- Hose leaks
- Cooling fan relays or motors
- Water pump, housing or gasket leaks
- Freeze plugs and core plug leaks
1 The OEM air separator tank is plastic and known to fail. They either split on the glued seam or the neck deforms from the pressure caps spring tension and heat cycles. If the tank splits it can cause unexpected coolant loss and overheating the engine, this can also result in engine damage. A deformed neck reduces holding pressure allowing coolant to escape and if unnoticed can also result in overheating. Pettit’s aluminum air separator tank upgrade is a direct replacement for the stock part and is far superior to the original plastic unit. The all aluminum- construction and added capacity not only makes it stronger but more effective as well. In an emergency the lever vent cap allows you to safely depressurize the system for repairs or inspection. Add some needed integrity to your cooling system, simple to install in 30 minutes or less and always in stock.
Aluminum AST, most RX7 FD’s on the road today already have our aluminum upgrade unit. Many owners have never seen an original and ordered ours before realizing their car already had one. The original plastic unit is black, with age it could appear as drab olive green, the top is square, the mini cap is the same size as the engines. Our original AST’s are round, usually silver or black with a large cap & usually a red vent lever.
Besides replacing the plastic air separator there are a few other simple inexpensive but important upgrades that every RX7 needs. is our 82C / 180F thermostat and 85C / 185F fan switch, together they can reduce operating temperatures 30C / 40F. New AST-SP, our AST now incorporates swirl pot action, hence AST-SP, The redesigned part further improves system efficiency by more effectively removing entrained air circulating with the coolant. The redesigned part also benefits from billet cap neck and hose nipples, all cnc machined from 6061 T6 aluminum then beautifully tig welded in the US to iso standards by some of the best welders on the planet. Offered in black textured powder coat and mill finish suitable for polishing.
The RX7’s closed cooling system works like this, with each heat cycle coolant is discharged from the AST raising the coolant level in the recovery reservoir, then during the cool down cycle negative pressure (vacuum) continues to increase until it allows atmospheric pressure acting on coolant in the recovery reservoir to push open the pressure cap recovery valve, thereby refilling the AST. If either cap is opened before the recovery cycle is complete it will probably be necessary to top off the coolant. In a closed cooling system you should never hear boiling, that typically means some air has gotten in and / or it's not holding pressure. First thing to check is the coolant level in the engine and AST, if there is any loss of coolant it it's important to find the leak and repair it.
Recovery Cycle, In warm climates it can take 8 to 12 hours to complete the cycle, best time to check is first thing in the morning before starting the engine, when you remove either the engine or AST cap, both should be full right to the top and the recovery reservoir’s dipstick should be up to the full cold line. If the system needs some coolant and the recovery reservoir is full that typically means the cycle is only half working, it's discharging the coolant when hot, but it's not recovering it during cool-down. That is the most common issue and typically means the AST cap is not sealing properly. Check the AST and it’s caps upper and lower sealing surfaces both must seal up 100% if there's any trash or debris on it that could cause it not to recover. The best way to figure this out is to make sure the engine and AST are full and check/note the level in the recovery reservoir, then when you return hot, the level in the recovery reservoir should be higher, the next day it should be lower and the engine and AST should be full. If it is still high the AST is probably low, until it's working properly it's a good idea to check it each time before driving, then you can observe the level in the recovery reservoir and know that it's working right. The caps can fail as well. Also, since the recovery reservoir is open to the atmosphere the coolant will evaporate and need to be topped off from time to time.
2 Engine coolant seal failures usually occur from overheating causing coolant loss with no external leaks. White smoke (steam) and or misfire on start up usually means coolant seals have failed.
3 The RX 7 FD Radiator is a quality part, but few are still in use due to the plastic tanks failing. Leaks are usually from the tank to core seal; any time overheating occurs it shortens the radiators life. They can be repaired, but an all aluminum unit is a better choice.
4 Hose leaks typically occur next to the clamp, pressure swells the hose against the clamps edge and it weakens eventually failing. Cutting back a little hose and re-clamping will usually buy some time and avoid a major leak. Our HD Silicone Radiator Hose Kits are rated for 65 psi, 5 times more than normal system pressure.
5 The Cooling fans and relays are another common problem, there are four relays powering 2 fan motors for low through high speed operation. They are controlled by the fan switch, A/C and/or ECU. Most FD’s have the Cooling System Recall, it allows the fans to operate without the engine running via a control unit mounted behind the ECU; however, one of the recalls harnesses is located under the hood and has connectors that are not hermetically sealed. After getting wet a few times the connections can weaken then when the ECU request high speed fans, the voltage drops and the connectors overheat or melt preventing the fans from hi speed operation which can cause overheating. We commonly service and replace connectors, relays and motors when they fail. Looks like ageing components and/or fan recall harness or a combination of both may play a part with several new problems that no doubt will cause 7 owners some severe headaches.
Proper and efficient cooling is essential if reliable performance and improved longevity is desired, so the cooling system is a key factor in optimizing the FD and liquid cooled engines in general, any engine can be damaged from overheating.
Whether you’re a new owner or an 18 year veteran, nearly every RX7 will need some cooling system updates and upgrades. We have several simple & easy procedures and a few inexpensive parts that have proven to get the cooling system working at peak efficiency..
6 Water pump leaks are less common due to better pumps and often leak when the system is cold and depressurized.
7 Core or freeze plug leaks are only common on engines with a neglected and rusty cooling systems.
#2 Oil Metering System
The oil metering system is responsible for lubricating the delicate apex seals, compression seals, and housing surfaces that are common to every rotary engine. Oil is fed from the engine oiling system (oil-pan) to a variable ratio-metering pump. Then it’s injected into the engine where it partially blends with the onrushing air-fuel charge. This incomplete blending and fuel-to-oil ratios of 400:1*and higher are cause for alarm. Also, unleaded fuels typically have additives designed to clean piston engines, then high combustion temperatures of the rotary together with Ethanol blended fuels cause the minute film to disperse and /or vaporize leaving all your critical surfaces clean and dry without protection. This causes increased friction and wear, resulting in decreased performance and longevity. With over 25 years experience and more than 2000 rotary engines built, we know excessive wear on apex seals, compression seals and critical surfaces is caused from inadequate lubrication. What’s all this mean, without extra lubrication added in the fuel, friction and heat will cause accelerated wear that is proven to cause premature failure of some expensive engine parts, great for Mazda’s profits but not good for you and me.
Protek-R fuel lubricant is proven around the world for over 20 years, when added to the fuel it reduces friction & wear adding performance & longevity. Developed in the late 80’s for our racing efforts and first released for sale in 1990.Protek-R had a major role in all our race victories, 5 Championships, over 50 SCCA national race wins, many top finishes in professional endurance racing like ALMS and several 24 hr Daytona Rolex Races, and GT Championship in 1998. There is no doubt that Protek-R provided extra performance and longevity to have results like these.
#2A Flaky Oil Gauge:
The oil sending unit is below the oil filter and approx 5 x larger than the 1/8" npt nipple that attaches it to the block, thus a nice moment is created, then harmonic frequencies through the RPM ranges and pulsations from the oil pressure regulator perhaps cause the wire connector to loosen grip on the terminal, usually a little squeeze on the connector to tighten it up helps.
#3 OEM Air Filter Box:
The oem filter box is well known to fail allowing dust, dirt & foreign matter to bypass the filter blasting the turbo compressor wheel with unfiltered air at the speed of sound. Another issue with the factory airbox is the air comes in from the intercooler air duct, so under moderate to hard acceleration the engine takes most or all of the air which prevents the intercooler from working. The first product we designed for the RX-7 back in 1993 was our Trak Pro Cold Air Induction System, it received its air from the front nose opening which instantly more than doubled the efficiency of the stock intercooler.
In 1999 Mazda also corrected the problem by feeding the airbox from a passage behind the front license plate on the new nose design.
#4 Ignition System, wires, coils & plugs
Install spark plugs Due to the rotary’s high combustion temperature, the spark plugs must be properly tightened for the most effective heat dissipation. Check your old plugs for flattened crush washers. Install the plugs, neatly route the wires and connect as shown. When connecting plug wires to the plugs, the boot will slide until metal to metal engagement is felt. If the boot resists sliding, spit helps. If loose plugs or other issues are found don't worry, what's more important is getting it right this time.
Coil harness routing RX7 FD:
The coil harness should be routed along the base of the coil mount exiting in front of the oil fill tube and over the top of the oil feed tube, then tie wrapped to the oil fill tube in position between the front trail and lead plug wires. On old coil harnesses eliminate the ground wire.
Plug wire routing RX7 FD:
Looking at the trail 2 or rear coil, the plug wire should point rear to 3:00-4:00 curving around and down connecting to the rear top trail plug. It should keep some distance from the coil’s primary plug and harness. For FD leading plug wires, the coils top position connects #1 lead plug wire to front lower (lead) plug.The bottom coil position connects #2 lead plug wire to the rear lower (lead) plug. When connecting plug wires to the plugs, the boot will slide until metal to metal engagement is felt,
#5 Sequential Turbo System testing, fixes & calibration
Unspoken secrets the auto industry hopes you will never know! The following information relates to turbocharger failure prevention and the general acceptance that turbo failures are normal and expected.. It is common to hear I always start my car and let it run for 15 minutes before driving. Then let it run for 10 or 12 minutes to cool the turbos when I'm done. In just 1 year of daily that can add up to an extra 150 hours of use, wear and tear, unnecessary fuel consumption and as a result, the polluting emissions.
That’s three strikes in my book, there has to be a better way. Letting engines idle to warm up dates back to the early days of automobiles and trucks, back then you had to warm them a bit just to make them go and they were so slow you didn't really need to warm the rest of the drivetrain. It's one of those handed down things my dad's dad and his dad's dad and uncle and brother that's how they did it and that's how we do it, we don't question it.
With today's vehicles idling to warm the engine has many negative points: only the engine warms not the driveline tires brakes or suspension. It causes unnecessary wear and tear creates unnecessary emissions and wastes fuel. If you want your vehicles to deliver the maximum performance and longevity, with minimum expense for maintenance & repairs as well as minimize your environmental impact from emissions / pollution, there is a simple easy way.
Instead of idling to warm up, just drive easy gently warming everything at once. It is a fact less use, (hours of operation) means less failures, fewer repairs, less cost and your stuff lasts longer. To accomplish this just requires modifying our thinking and some changes to how we use things.
Common Sense that’s not so common:
One simple change and three strikes become three home runs. If your car is not moving turn the engine off, no fuel is being wasted, no unnecessary wear and tear on the equipment and fewer emissions are being generated. All those benefits from making one simple change. but with turbos everyone agrees, idling is necessary to cool down the turbos. For countless years Idling is how turbos were cooled its been the only way, until now.
Here’s why, idling still produces combustion feeding the turbo hot exhaust, did you ever notice even after idling for a few minutes, four or five hours later the engine still too hot to touch.
Endurance road racing turbocharged rotary engines is a challenge to say the least. Our turbos seemed to be holding up well as long as we serviced them every two races, polished the turbine end of the shaft and maybe changed the bearing, otherwise after two races they would fail. We theorized such a simple device a shaft with two bearings should be much more reliable. Then after night practice for the Rolex 24 at Daytona we noticed even after 10 minutes idling the turbo was staying red hot. The instant the engine shut off the color would dull, After inspecting some failed units and doing research, we were confident that heat transfer from the turbine wheel into the bearing housing was causing the thin oil film to burn forming carbon, coking up the bearing and causing the failures.
“Cool down cycles” is the name for a new procedure we decided to try, after which bearing failures became a thing of the past. Now our turbos lasted many races and the occasional failure was not bearing related, it was the result of other bad things we had done.
How it works.
When you arrive at your destination immediately shut the engine down, then turn the key back on allowing the fans to cool the radiator, after a minute or so restart the engine for 10-15 seconds, the cooled radiator fluid circulates through the turbos and fresh oil pumps on the turbo bearings and shaft preventing carbon and coking of the bearings. Usually 2 cool down cycles rejects enough heat to prevent carbon and coking of the bearings. At the track misting water on the radiator and oil coolers while performing 5-6 cool down cycles rejected enough heat that you could touch the turbo. With out cool down cycles the engine and turbos stay too hot to touch for hours.
turbo on a 3 rotor 20b engine glowing after only a five minute run on the highway
Warm up the vehicle, letting it idle only warms up the engine, not the transmission, rear end, brakes, suspension or tires. It much better to drive it nice and easy warming everything together. In cold climates a block heater will keep the heater ready to warm you up quickly.
Job security is why you never heard this before. The shops want to keep cars and trucks with broken turbos lined up to be repaired and turbo builders want them piled up at their doors.
PCV valve: The oem PCV valve on RX-7 FD’s is a standard plastic valve, if it fails to seal when you accelerate it can allow boost to pressurize the crankcase creating oil leaks. in 1995 Mazda eliminated it from the RX-7 FD’s. it's a good idea to remove it from any turbocharged or supercharged rotary engine and connect the crankcase breather nipple to a catch can.
#6 Minimum boost set This applies primarily to FD’s with ongoing drivability / performance issues where a pile of money spent at dealers and various shops either didn’t help or made problems worse. Common sense again dictates that when poor performance or drivability problems are present at light throttle and at minimum boost levels, attempting repairs and/or testing with ECU controlled boost can add to inconsistencies as the ECU tries to compensate for other problems as well as put unnecessary stress on internal engine seals & components, this typically shortens engine life or worse, may cause a catastrophic failure.
The first step is to set the boost to a minimum level helping to systematically isolate and correct problems hopefully without causing more damage.
Step 1, No boost testing
All testing to correct drivability problems that are present at light throttle when negative manifold pressure (vacuum) or “0” (no boost) should be corrected before attempting to use boost, once proper operation is achieved (ie: idle & drivability smooth & consistent) with all off boost driving, good progress is made and minimum boost testing can proceed with confidence.
Step 2, Minimum boost testing
With a wide band AFR connected we recommend adding 2 psi at a time until the desired boost is reached and verifying correct & stable AFR’s each time.
#7 More Boost
Over the years we have found that raising boost levels (more boost) above 10 PSI should only be considered on cars that have good drivability & consistently perform with smooth effortless acceleration from light to full throttle thru all the RPM ranges.
At this point the delivery of power and the level of performance will usually scare passengers, while providing a fun and exciting driving experience for those behind the wheel, even with a minimum boost setting the FD is deceivingly fast, this is when tire condition, brakes and suspension are critical factors, do not fail to realize their importance, a small problem at speed can turn fun to fatality.
101 “How much HP gain will a larger I/C deliver” this is a common question we hear often, however; common answers are all over the board, 15-30%, 25-100 HP etc...Common industry answers because the notion you can gain some HP sells parts. Since few sales people have a complete understanding of every theory, they often repeat what they heard to facilitate a sale without fully understanding themselves, but nearly always prefer selling parts that generate the highest profits and commissions, even when sometimes those parts provide little or no benefit The facts are simple physics, air to air intercoolers can only improve two variables, reduce pressure drop and / or reduce the rate of charge air temperature gain.**
Using only ambient air flow they can not reduce charge air temps below ambient. I/C upgrades that reduce pressure drop provide more power by delivering more boost to the engine and gains from reducing the rate charge air temperature increases are from denser air (more oxygen) entering the engine at a given point than before upgrading.
I/C efficiency is directly related to ambient conditions (the weather) and air flow volume through the I/C, the laws of physics dictate that the exchange of heat via ambient air can not add HP but rather slow down the rate at which power is being lost to the rising temperatures** Under certain conditions when ambient temps are cold enough for temp gain to stabilize, then more power overall is produced than could be with a smaller I/C **
As air molecules are compressed to create boost, the friction from the molecules being squeezed together generates heat, the I/C’s job is to cool it back down. So the cooler the air is entering the turbo the cooler it will leave the I/C and enter the engine. cooler denser air allows more volume to be packed into the combustion chamber at the same boost setting, this results in a bigger bang, IE (more hp).*** .
So the I/C’s job is to reduce the rate that charge air temps rise and slow down the rate your power is being lost, so flow rates and pressure drops are a concern when upgrading to larger intercoolers and many popular systems have elaborate piping that add extra bends and connections as well as have no provision for cool outside air feed to turbo(s), because of this many front mount intercooler kits can be less effective than the stock system. .
For example, with the RX-7 FD, using the stock I/C and a Pettit Cold Air induction @ 10 psi with ambient temps at 85deg the air entering the turbo is approx. 90-95 deg F, the compressed air leaving the turbo is around 190-210deg F, if the stock I/C only drops the air temp say 30-35 deg, then charge air temp = 160 deg
Air in at 90F. @10 psi + 100F stock I/C – 30F charge air =160F
With most front mounts on the same 85deg day running 10 psi boost the air (heated by the radiator) enters the turbo @ 190-220F,
compressed air leaving the turbo is around 290-320deg,
even with the big I/C and a 90-100deg charge temp drop, charge air = 220deg
Air in at 190F. @10 psi + 100F FMIC I–100F charge air =190F
That example shows the stock I/C to deliver 30deg F cooler charge than a typical FMIC w/o provision for cold air to enter the turbos.
With the Pettit Coolcharge III system the RX-7 @ 10 psi on 80deg day we could expect air into turbo @ 90-95deg (from cold air induction) after turbo say 190-210deg, the CCIII intercooler drop min 80-90degF, charge temps = 100 deg,
***provided ignition & fuel requirements are correct.
Thermal management are you wasting horsepower?
Thermal management technology has evolved to an art. Enthusiasts everywhere are realizing that potential horsepower and reliability gains are significant and are worth far more then the cost. Auto manufacturers go to great lengths to reduce heat radiation from exhaust and turbo systems on to the surrounding components. They use multi layer heat shields, reflective barriers and even ducting of air. All manufacturers agree that proper shielding of radiant heat is extremely important. Any vehicle can benefit from this technology, especially high performance and racecars.
RX7’s with single turbo setups seem to gain the most from this technology. Instead of just wasting some horsepower, with the rotary it’s easy to waste engines. Since most aftermarket single turbo kits do not come with heat shielding and most installers don’t spend the necessary time to build adequate shields, it leaves exposed radiant heat to blast the lower intake.
On 3rd Gen setups it usually favors the front runner, this superheats the charge for the front runner just as it enters the port, not only does this raise the charge temperature in to the danger zone, but makes you think the engine is running rich, “tuners” unknowingly lean the overall mixture to compensate, but then the cooler rear rotors is dangerously lean. Also the air temperature sensor is located upstream where the temperature is cool, therefore; you would never know that radiant heat is causing this mixture imbalance and robbing horsepower and reliability. 90% of the FD single turbo engines we open have rear rotor failures which further attests to this condition.
Pettit Racing is producing Cool Power Thermal Management Systems designed to fit most RX7 single turbo kits. These kits are easy to install and the benefits are priceless. We also have a kit for the factory twin turbo setup as well.
Pettit Racing Cool Power Kits use the latest technology for thermal protection.
Common items / procedures for RX7’s that we often perform:
Upgrade plastic air separator tank to aluminum
Eliminate AWS (accelerated warm up) it causes high revs on cold starts . Eliminate PCV valve, a sticky valve allows boost in the crankcase, promoting oil leaks.
Sequential System Upgrade, Replace hardened vacuum / pressure lines w/ HD hoes,
Relocate sequential turbo systems pressure control ck valve & add overboost safety circuit
Bypass oem PC & WG duty sols for min boost setting / testing
Upgrade chassis & engine ground with our free kit
Eliminate recall jumper harness on fan motor relays
Upgrade oem 92C / 198F thermostat to 82C / 180F thermostat
Upgrade oem 98c / 209F fan switch /to 85C / 185F fan switch
Upgrade oem radiator to all aluminum unit
Upgrade oem rad hoses to hd silicon
Upgrade turbo cooling, AST & bypass / transfer hoses to hd cooling line
Replace drive belts, if they have any cracks
Upgrade old original rubber brake lines to dot ss teflon
Upgrade flush and bleed the brake system, fluid, pads , etc may be original
Service Trans and diff.