Stages of Upgrading

Last updated: May 9, 2000

Upgrade Introduction

You have two choices to make first:

  1. Go with parts from a single tuner such as Pettit, Mostly Mazda, Tri-Point, SR, or PFS

  2. Go with best of breed parts.

The single tuner option is easy. The tuner has hopefully matched everything to work with the rest of their parts. They will offer packages for different levels of tune (i.e.- Stage I, Stage II, etc.). If you don't have the time to do the research, this is the way to go. You may also get a discount if you buy all the parts in a stage (over buying them piecemeal).

If you do buy best of breed, you have to put together your own upgrade path and do the research to make sure you don't blow your engine by doing things in the wrong order. The advantages to this option are that you may end up with a better overall package if you feel that a particular vendor makes a better intercooler while another makes a better intake, and a third has a better exhaust system, while yet another has a better computer. You will also learn a lot more about your car by doing this research. The car will be more uniquely yours too.

I went best of breed and did a lot of research, and my car ended up getting parts from mostly one vendor (Mostly Mazda) for the engine. The suspension is from Tri-Point. Best of breed for me ended up being a lot like single vendor.

Another comment: I personally wouldn't get too wound up over getting beat in a straight line unless you ONLY want to drag race. The RX-7 will turn too :-) something the Camaro doesn't really do too well. Save some money for the suspension and tires/wheels. Then invite the guy to Road America or other track near you. That will be really embarrassing for him.


One common question is "How many mods can I do before I need to upgrade the computer?". The question has to do with what you can do to the car before it starts to run lean and experiences detonation, which will kill a rotary. Mods that improve airflow start to become dangerous if they let it flow too freely, and the stock computer does not provide enough fuel to go along with the extra air. Since the stock computer uses static maps, it either needs to be reprogrammed (see M2 Performance, Pettit, XS). See below for more info, or the engine management computer section. --Editor

Date: Mon, 14 Aug 2000 13:21:36 -0700 (PDT) From: e s (
Subject: Re:(rx7) [3] Intake, DP, CB and no ECU upgrade? LONG!

I'm going to throw some numbers out on to this thread. I know its been cover MANY times, but I have never seen numbers other than my own readings so here goes.

My mods probably wont directly relate to anyone else since everyone does the catback before a midpipe, but I figure the midpipe will make a bigger deference than the catback, & considering I was only running about 8-8.5PSI on the secondary turbo the "intake, DP, CB" configuration at 10 PSI will probably be equal if not worse than my config.

Disclaimer: These are rough measurements taken with a very high quality Fluke 87 volt meter on a very low quality Bosch O2 sensor, & an Autometer boost gauge.

OK, Once I had the intake + DP config I came real close to overboosting one cold morning so I installed a needle valve into the wastegate actuator pressure line. This left me with 10PSI pri, & 8-8.5PSI sec. (don't ask me why, but the Profec B seems to have fixed it)

My maincat clogged so I installed a midpipe, & figure that with only 8PSI on the second turbo that I'd be pretty safe,

Well I did runs with the intake + DP, & measured around .97x, but as the RPM rised above 6K the O2 voltage would drop down to about .927ish I figured that to be plenty safe.

After installing the midpipe, I was measureing the .97v. (around 3K on the tach) but at 5K with 8PSI the voltage would drop down under .9v. With it going as low as .81-.80v. by 6.5K.

That is when I decided that I wouldn't run over 4-4.5K until my Power FC arrives, in fact I rarely drive the car right now.

So that is proof (kinda) that 3 mods with no fuel mods other then a K&N fuel filter, & no stock filter make the FD R-REX run lean.

Upgrade Order - Reliability

If you are just looking for reliability, no performance gains, then get the J&S knock sensor, around $600 - 700. This will prevent lean conditions and detonation, which will will destroy the apex seals.

Get a boost gauge so you will know what the turbos are doing. About $50 - 100, depending on model, mounting method, etc.

Add an N-Tech or Tri-Point downpipe for about $400 or less (stainless, mild steel for around $250 - 300). This will make the engine run a lot cooler, possibly helping to save the O-rings.

Add the Tri-Point or Pettit air separation tank for less than $200. Or just do the elimination mod (about $20 - 50 of parts).

Those mods should go a long way to helping engine reliability.

Other than mods, make sure you do all maintenance as recommended, if not more often.

Also, do the tests listed in FAQ --> Buying a Used 93 - 95 RX-7, to make sure your car is OK to start with.

Upgrade Order - Performance and Reliability

I get asked this a lot, so here is the proper sequence for adding mods so as to not blow the engine:

  1. Catback exhaust (get the Tri-Point, Racing Beat, Pettit, N-Tech, or PFS one) (or ASP if you also want to remove the cat, although it is better to replace the downpipe and keep the main cat at this stage).

  2. Replace the precat with a downpipe (Tri-Point, N-Tech, Pettit, etc) (note: this will technically put you out of compliance with the emissions laws, but in fact the car will pass the sniff test. It will not pass the visual test which says that there must be a precat on this model car. But most people get away with it since it will pass the actual test.)

  3. Get a high flow cat (Random Technologies, others). (Or wait until later to completely remove the main cat.)

  4. Intake (Mostly Mazda, N-Tech, Tri-Point, Pettit, FTL).

  5. At this point, and maybe even before the intake, you will want to get the engine management computer upgraded (Mostly Mazda, Pettit) or get an aftermarket totally tunable one (Electromotive, Haltech, PFS, Wolf EMS). This will enrichen the mixture and keep the engine from leaning out and detonating. Detonation is deadly to a rotary!

  6. Intercooler (ASP Race IC (the XL one) or ASP Medium IC).

  7. Replace main cat w/ midpipe (straight pipe).

  8. A J&S Knock Sensor is invaluable - it could save your engine. Install it as early as you can in this process. (Note: if you are going to buy an engine compuetr such as an Electromotive or Motec, these will come with (or have as an option) a knock sensor. No need to buy two.)

  9. Any mods beyond these will require upgrading the injectors, and/or fuel pump and regulator (see the rest of this site for more info on these). Some people say that if you remove the main cat after the rest of the upgrades, that you will need to do the injectors as well. Some of the vendors that do computer upgrades (at least Mostly Mazda) say that their computers will not control the bigger injectors, so you have to go to ones like Electromotive or Haltech.

For more details on these components, see the rest of this site, under the Upgrades --> Engine & Drivetrain page.


From: Jim LaBreck (
Sent: 18 September, 1999 10:04 AM

...That is exactly why it is so inexpensive to make a Supra Turbo "BPU". The OEM MAF sensor can adjust for increases in air flow caused by removal of the cats, replacement of the exhaust and intake, and the addition of a more efficient intercooler, since all air going into the "system" is metered. An appropriate amount of fuel is then injected, and since the fuel system on the Supra is good for ~500 RWHP without modification, the only additional upgrade necessary is a boost cut controller.

The downside to using a MAF sensor, and there are a couple, is that it's a restriction in the air flow path. In order to improve the flow of the intake system, it is necessary to convert it to a speed density system using an HKS VPC or aftermarket stand-alone computer, and then you have the same problems with tuning that the RX-7 has. It is also a weak link in the system if a failure of the pressurize system occurs. If an intercooler hose on the RX-7 pops off, it will continue to run "naturally aspirated". If an intercooler hose pops off on the Supra, none of the metered air is reaching the engine, but the fuel to match it is... the result is a huge black cloud of smoke and unburned fuel and the engine sputters and dies and will not remain running until the breach of the system is fixed.

Since the RX-7 does not have a MAF sensor, it has the same problem as a Supra with a speed density conversion. Adjusting adequately for the incoming air flow requires careful tuning, and is not simply plug-and-play. The problem with both cars, once exhaust components have been swapped and the intake has been opened up is one of efficiency. The system simply flows too well for the internal wastegate system to vent enough exhaust energy away from the turbines of the turbos and the result is boost creep or spiking. While I have read that "ideally" a turbo engine should require no back pressure, and the bigger the pipe leading away from the turbos the better, this is just not the case in a street-driven car which is not capable of providing enough fuel (as in the case of the RX-7) when spiking and creep occur, or in a car which can produce an extremely high level of boost (27 psi) with the stock twins, but is so far out of the efficiency range of the turbos that the resulting heat will almost always result in detonation. Despite the fact that the Supra's internal wastegate is at least 150% larger than that of the RX-7, it still has problems controlling boost when all restriction is removed. The solution, which is fairly simple, is to maintain "some" of the exhaust system's back pressure to prevent spiking and creep from occurring. Anyone who thinks they can simply "control boost at 10 psi" after removing all the restrictions of the intake and exhaust path hasn't done the mods yet. It is possible that even an electronic boost controller won't be able to compensate or limit the system to just 10 psi, even with an enlarged wastegate orifice, if the system flows "too well".

The solution is to keep or add some restriction to the exhaust flow. I found that not only did the Racing Beat twin tip exhaust on my car look better and cure my backfiring problems, but it also added a reasonable amount of restriction the exhaust path and allowed me to control boost at whatever level I desired. A friend who was unable to control boost with an A'PEX AVC-R because of his PFS cat-back, Pettit resonated midpipe, Bonez downpipe, ASP medium intercooler and Pettit cold-air intake (working back to front) removed the midpipe and replaced it with the mildly more restrictive Bonez hi-flow catalytic converter, and now boost is controllable and rock solid. This is also on a car, as was the previous example, where the wastegate orifice had been enlarged. Saying that you'll simply limit boost to 10 psi and doing it are two different things. I think I've shown a couple examples of situations where that might not be possible. The smart move is to upgrade your fuel computer by reprogramming (or with a piggyback system) to cope with additional fuel demands caused by the modifications to the car, even if you aren't planning on running higher boost. Sandy Linthicum didn't put a Motec in his car to run 18 lbs. of boost. He put it in to fine tune the system and get every bit of performance out of stock boost levels, but also to ensure that he wouldn't be replacing an engine again and again because of aggressive driving on the track. Yes, Virginia, there are problems with running 10 lbs. of boost, even if it is "only" 10 lbs. of boost.

The main problems are increased air flow and reduced air temperature. To make this short and simple, Shiv's results detailed in the latest installment of "Project RX-7" in Sport Compact Car vividly show the reduction in intake temperatures that a cold-air intake and large (M2 medium) intercooler can produce. While 10 psi is still "just 10 psi" (where pressure is concerned only) in a system which has not had its internal volume increased, most of the intercooler kits do come with additional piping which does just that. In order to see 10 psi at the manifold with a larger intercooler and piping, more air must be moved by the turbos to fill the additional internal volume to that pressure level. Also, the air will be more dense, being cooler because of the improved efficiency of the system. The additional air flow (and Shiv measured a 1 psi increase at the manifold just from the addition of the M2 intercooler) and the colder, denser air both combine to pack more air molecules into the combustion chamber with each cycle of the engine. Because the MAP sensor (manifold absolute pressure) still sees "only" 10 psi, the ECU cannot efficiently compensate for the additional oxygen in the combustion process and injects the amount of fuel which it believes is sufficient for the conditions reported by its sensors. The result is a lean burn, with too much oxygen and not enough fuel. While the pressure is lower, and less likely to cause the engine to detonate, the increased heat of the lean condition can (especially with extended use) cause hot spots to occur and can pre-ignite the air/fuel mixture, or cause an uneven flame front, resulting in detonation and extremely high "cylinder" pressures. The result, of course, is that you end up replacing an engine.

I know that many disregard the advice to improve their fuel system and their engine's live to tell about it. Perhaps the same variances in climate and elevation which let the Arizona boys (assuming they're not all just lying bastards) get away with running full boost in their Supras, while I can only run 1.4 Bar in the Northwest without experiencing ignition timing retard from light detonation allow these RX-7 owners to "get away with it". I wish them luck. I also understand that there are almost no visible indications of fuel system modifications and on a car which most buy for looks and a certain amount of "flash". It's the highly visible items (like that huge IC) that people are after. Just because you can't see the components or brag about them, doesn't mean that they're not necessary or that you shouldn't very seriously consider upgrading your fuel system before getting carried away with modifications which might make its limitations glaringly obvious. I always recommend fuel modifications be taken care of early in the process of modifying the car, and I won't recommend running any higher than 13 to 13.5 lbs. of boost, even with an upgraded ECU, fuel pump, or fuel pressure regulator, because of personal experience, but also because you simply can't expect a car in another part of the country (let alone in the same city) to react to modifications in exactly the same way as yours does. Just because someone is "getting away with it" doesn't mean you will. Trust me on that one, I know what I'm talking about.

So let's agree to treat each car as an individual case and not make blanket statements like "it's fine to just run 10 psi on a fully modified car" because someone managed to do it. Colder climates are more likely to cause problems with a configuration like this, and there are many other factors which can cause engine damage even in a controlled system, if all factors are not taken into account. You might get away with running lean because of low boost pressure, but you might (for example) get a bad tank of gas from the 7-11 or BP which lowers the resistance of the fuel to detonation in the same conditions you were previously "getting away with", and the result is one more blown engine. It can, and does, happen. With the rotary engine, it's been proven fairly conclusively that boost pressure is not necessarily what kills the engine. There are many racers using stock 2mm seals with pressures in excess of 20 lbs. of boost. The problem is the fuel system, and making sure that it provides an adequate amount of fuel taking all factors into account. While an engine running 20 lbs. of boost might be more likely to detonate at a slightly richer "lean" condition because of the increased pressure, an engine running at "only" 10 psi can detonate because of a lean condition also.

Consider that a naturally aspirated piston engine can detonate because of compression ratio and octane level, even with the appropriate amount of fuel being injected for the air entering the engine. Then consider the same system under 10 lbs. of pressure. The compression ratio of the rotary turbo is lower in order to reduce the chances of detonation, but if the air/fuel mixture varies or if the octane levels of the fuel vary, detonation can happen.

Not to fuel the fire, but one thing that no one has mentioned is load on the engine and the part it plays in boost levels and increasing the chances of detonation. It'd be interesting to do a survey and find out what gear people were in when they suffered damage to their engines. I'm willing to bet that in most cases, it was 4th or 5th gear... anyone want to speculate as to why this might be the case? How about partial throttle boost, which even on a "controlled" system can cause boost to creep to higher than normal levels?

No advice covers everyone's application. The best policy is to treat your car as an individual case, and since opinions are like you-know-what, collect as many of them as needed to make an informed decision on how you choose to modify your car. You will have to live with the results of your own choices, unless a shop does the work for you, and even then it is likely that because the modifications are "intended for off-road use only" or "because of application, all warrantees implied or explicit are null and void", you may be stuck with fixing your own mistakes. While some might argue that because I have not only blown two engines in my RX-7, but also managed to blow one in my "bulletproof" Supra, that I'd be the last one you should listen to. Others might argue that precisely because of these reasons, that I'm one of the best sources of information on "what not to do".

Since the fuel system on the 3rd gen. has been shown to be less than adequate time and time again, I'd urge giving careful thought to fuel modifications that will increase the ability of the system to provide proper fuel. If you're not planning on running more than 13 psi or planning on sticking to stock boost levels, then pressure is not what you need to worry about. Adequate fuel delivery is. My recommendation is, and always has been, to put as much money into your fuel system as you would into your intake and exhaust or your intercooler. You may not be able to see the modifications, but you'll sleep a little better knowing that they're there. For the same reason that you wouldn't trust the security of your Diablo to a $100 aftermarket alarm, would you really trust the health of your expensive rotary engine to $0 in fuel modifications? Do the right thing, and perhaps more importantly, become knowledgeable about your car. Be able to make informed decisions based on solid facts, and know how your car reacts to modifications that others may be getting away with. Do one modification at a time, if possible, and you will be able to back-track to a previous known "stable" configuration. Do it all at once like I did, and you will try numerous configurations before finding out that a simple change in exhaust could have controlled the boost levels and prevented the loss of a second engine despite having an HKS EVC III in the car.

Plans, Stages, Phases of Upgrades

Date: Fri, 15 Aug 1997 02:49:33 -0500
From: "Kevin T. Wyum"

A couple people have mentioned in the past that they are not sure of what order to do things with a third gen. They say the other cars they own have stages of modifications that are safe. This is probably a pretty good idea. I can't count how many times a person has asked, "what should I do next?" So I'll put it to the list to debate the order that things can or should be done and to come up with a stage I II III IV V and so on. The main thing I would tend to suggest is two versions based on what I have seen. A Race stage list and Legal stage list.

Here are some ideas. The important part is that it be a universal with no pushing of any particular shop

Race Stage I

Or all in one like mine
Boost Gauge

Legal Stage I

Air intake
Boost Gauge

Race Stage II

Flywheel (optional)

Legal Stage II


Race Stage III

Boost control (if not on computer)
Vacuum hose tied
3 wire O2 sensor (run high octane fuel at higher boost)
Front swaybar
Springs and Shocks
Colder temp range plugs

Legal Stage III

Flywheel (optional)
Hi Flow cat
Downpipe (optional)*
Front swaybar
Springs and Shocks

Race Stage IV

Larger Turbo's (single, super 50 stock conversion or huge twin like Trev 
and I)
Non Sequential conversion for upgraded stock (optional)
Ignition Amp (HI6 etc.)
Fuel system upgrade  (pumps, injectors size etc.)
Roll Bar
Coil Over adjustable ride height susp.

Legal Stage IV

Larger Turbo's...
Non sequential conversion (optional)
Ignition Amp
Colder plugs
Roll Bar
Coil Over adjustable ride height susp.

Race Stage V

Stand alone ECU (Motec, Haltec etc.)
Ported motor
Internal motor upgrades (apex seals, oil  rings etc.)
Bushings etc.

Legal Stage V

What's the point?

Race Stage VI

What ever else I missed.

I can see that there should probably be seperation between power and suspension mods. Most people do the suspension at different times and it really doesn't matter what order you do it in. For this reason I left things out like brakes and pads, rotors etc. Maybe there should be a different Stage list for suspension. So let's see what the list does with this. It would be nice for each vendor to follow a proper order so that people stop blowing motors etc. and do things in a reliable fashion.

I (Steve Cirian) had posted a query a couple of months ago asking if there was any concensus as to what order you should do upgrades in. Sort of a "levels of tune", if you will. And then I went on vacation, unsubscribed for about 6 weeks, and didn't get a chance to check and see if there was any discussion on the list on my question. I did get a couple of responses from Scott Stone, Mike Avila, and Steve Grigory (plus all the other posts I saved along the way - thanks everyone). So anyway, since I have started to mod my '95, I thought I would post the results of everyone's input that I have received so far, as well as my research.

Contributions to this are welcomed and encouraged, especially if you have alternate manufacturers, parts, or sources. Or if you disagree with the levels / priorities to which I assigned upgrades.

My goal in listing the manufacturers for a specific part would be to list them in descending order by how many people are using/recommend that specific part (understanding that this may not get you the "best" part, but at least would give an idea of what people are running). These parts are what I am running, or what I would buy if I had it to do over again - not that I would make many changes. As one vendor flame war has pointed out, there are varying opinions on parts and the vendors that supply them. Translation: yell really loudly and I will buckle under the pressure and change the order in which I list these.

As far as the sources go, the goal would be to list the lowest priced vendor. I put prices in, but only because I have ordered these parts, not because I did any research. I really had the urge to buy stuff, so I called Mazdatrix or the other vendors recommended on the list and just ordered it RIGHT NOW ;-)

I geared this to the 3rd gen, since that is what I own, and where my (meager) expertise is. The same format could be followed for the other gens if someone wants to take that on.

Here is what I have so far:


For minor, relatively inexpensive upgrades such as manuals, items not really giving performance increases, but more of the things that will help reliability. These items should not bump you out of the stock classes for SCCA Solo II autocrossing.

Mfg		Description		Source		Part #		Cost
Mazda		Shop Manual		Mazdatrix	95-018B-9999-95	$ 80.47

Mazdatrix	Catalog			Mazdatrix			$  9.00
Racing Beat	Catalog			Racing Beat			$  3.00
PFS		Catalog							$  free
Pettit		Catalog							$  free
HKS		Catalog							$  free
GReddy		Catalog							$  ????

HKS		Turbo Timer		Mazdatrix	4101-RA006	$162.99
(GReddy and others also sells timers)

HKS		Turbo Timer		Mazdatrix	4103-RZ002	$ 33.67
		Wiring Harness	

Autometer	Boost Gauge		Jegs Racing	2401		$ 40.??
(You can get a liquid filled gauge for a little more)

Mazdatrix?	Boost Gauge	 	Mazdatrix	4507		$ 34.50
		A pillar mount	

Hawke		HPS Brake Pads 		Racer Wholesale	

Motul		Brake Fluid		Racer Wholesale

K&N		Drop-in Air Filter (for stock air box)

Red Line	Tranny & diff oil

Taylor		Spark Plug Wires, 10mm	Taylor
(Magnecor also makes good ones)

NGK		Platinum Spark Plugs	Pep Boys
(note:  the car already has these, but listed here for maintenance purposes)

???		Silicone Vacuum Hoses	Mazdatrix, others

TOTAL									$


This level would start to get into the serious stuff, more expensive mods, and would definately be the performance enhancing equipment. These items will bump you out of the stock autocross classes, but hopefully keep you within the A Street Prepared class.

It may make sense to break this into two levels, one for the cheap stuff (or maybe the "must-do", like the exhaust), and the other level for the expensive pieces.

Mfg		Description		Source		Part #		Cost
Cusco		Strut Brace (not R1/2)	Rotary Performance		$180?	
(Greddy and others also sell these)

Tri-Point	Downpipe 
(A lot of others make these as well)

ASP		Exhaust			ASP				$800?
(incl. catback and midpipe)
(Tri-Point also makes these)
(If you want to leave the cat in place, get the Racing Beat)

Tri-Point	Intake (replaces stock air box)			$500
(Mostly Mazda, N-Tech, Pettit, PFS, and others also make these)

Electromotive	Computer		Tri-Point			$2500

K&N		AF meter		Jegs					$100

ASP		Race Intercooler

Rotary Performance	Power pulley

Penske		Shocks	Tri-Point
Eibach		ERS Springs	Tri-Point				$4500
(note - if this is too much, get the double-adjustable Konis w/ Eibach 
(don't know which kind of Eibach))

Tri-Point	Tubular Anti-sway Bar (front)	Tri-Point		$450
Racing Beat	Solid Anti-sway Bar (rear)	Tri-Point		$125

Kumho		V700 Tires		Tire Rack

Complete	Race Wheels		CCW				$350 each

Simpson		Racing harnesses	Simpson

TOTAL									$


Do just about everything left, but leave the car street legal.

Mfg		Description		Source		Part #		Cost
		Engine porting, 3mm apex seals, etc.

Crane		Hi-6 Ignition	Jegs

???		Fuel Pump

???		Fuel Injectors	

Autometer	Misc gauges, e.g.- fuel pressure, oil temperature, EGT

Mazda		2nd oil cooler (if not R1/R2)

Centerforce	Dual Friction Clutch (CFDF)

???		Light Flywheel

Brembo		Brake rotors

Brembo		Brake calipers

		Metal brake pads

Pettit		S.S. brake lines

		Roll bar

TOTAL									$


Add whatever components are needed for serious racing. Need to check the SCCA rule book for required safety equipment, etc.

Mfg		Description		Source		Part #		Cost
		Roll cage

		Fire extinguisher

		Fuel cell

		Strip interior, airco, glass, etc

Sparco		Racing seats

Momo		Steering wheel

TOTAL									$

Mfg		Description		Source		Part #		Cost
		Rear wing (if not R1/R2 or it just ain't big enough)

Mazdatrix?	Front spoiler (if not R1/R2)
PFS 		(makes a huge intake front valence replacement)

RE Amemiya	no-pop-up headlights
ASP		(fabbed out of PIAAs)

Mazda, etc	Bra

Mazda, etc	Car cover

JC Whitney	Fuzzy dice (just kidding, seeing if anyone is still 
		reading this far into the list)
TOTAL									$

Date: Tue, 26 Aug 1997 11:23:44 -0700
From: jramos@sunup.Corp.Sun.COM (Joe Ramos)

Let me give you my OPINION on how I would proceed. This also depends on where you want to end up, and how smog-legal you want to be (a concern I have to have here). This will take you to 350+ hp. This is the way I would evolve a car:

        A.  Install boost gauge ($100-300)
        1.  Replace stock air filter with K&N ($40 - 5 hp)
        2.  Replace stock muffler with free-flow cat-back ($400-700 - 15 hp)
        3.  Replace main-cat with midpipe ($160 - 15 hp)
        4.  Replace ic with larger unit.  ($1200 - ?)  This requires
            replacement of stock airbox ($500 - 15 hp), also, as larger
            ic will not fit with stock airbox in place.
            (You will now have a stock airbox with the K&N
             sitting on a shelf)
        5.  Install fuel management/boost control for higher
            boost levels. ($1500-5000 -  boost dependent)
        6.  Replace pre-cat with downpipe ($400 - 25 hp)
        7.  Upgrade turbos ($1100 - !!!!!!!)

$ are estimated prices for new product. Hp estimates are subjects for much discussion. You can get used product usually for 40-50% less.

Date: Mon, 22 Dec 1997 11:32:37 -0800
From: 93 RX-7 R1 <>

Let's face it, the truly perfect 3rd gen would turn 10.0 1/4 miles, have 1.10 G's of lateral accelleration, and get 20 miles to the gallon, but this ain't it. I've been gathering info from the Collective (rx-7 list) for the last month or so, to see if I could figure out how to make sub-12 second (on street tires), road racing daily driver. Some other things that influenced my decisions were that it had to be "legal, more or less", reasonably quiet, and theoretically drivable in stop&go traffic. Spontaneous combustion of the engine compartment was to be avoided if possible.

I estimated that we need somewhere between 360 and 400 hp to have fun.

What this is, is a compilation of data on all of the cars I've been able to find detailed HP and engine configuration readings on, along with pestering a few people about details along the way. I've tried to come up with a list of mods that are internally consistent, meaning that if you do all of these mods, you will not break some unforseen other component. Where I wasn't sure how much things would cost, or which brand would be the best one, I left a ?. Feel free to fill it in if you know. My timetable to completion is approx. a year, with 3 phases currently.

So, tell me what you think:

Item [Cost Estimate]

No power steering, almost no air conditioning.  [FREE]
Remove Air Pump	[FREE]
Remove boost restrictor/pill in the line between the primary turbo 
compressor elbow, and the wastegate actuator.   [FREE]

Boost gauge		[$80.00]
turbo timer		[$150.00]
A/F meter		[$100.00]
Fuel Pressure gauge     [$100.00]       
Knock Sensor, J&S       [$50.00]        
Intercooler, ASP medium [$1,800.00]     
Intercooler Brackets, Trev alum.        [$?]    
Pettit air intake       [$500.00]
Pettit power pulley kit [$400.00]       
Crane hi-6 ignition,    [$200.00]       
Downpipe, ?     	[$350.00]
high flow cat, ?        [$200.00]
pettit cat-back, stainless, dual-tip    [$450.00]
GAB adjustable shocks,  [$700.00]
aluminium radiator overflow cannister.  [$150.00]
10mm spark wires,       [$85.00]
colder spark plugs,     [$25.00]
tie-down of all vacuum lines,   [$100.00]
PFS silicon hose kit    [$150.00]
Redline Synthetics all places except engine.    [$50.00]
5 way harness.  	[$250.00]
Eibach springs 		[$400.00]

Fikse FM5 17"X10" wheels in the back, 8.5" in the front.
P255/40ZR17 tires on the rear and P235/45ZR17 tires up front.
Dual hawker batteries (moved to the back)               $250.00
Engine Work, including:         
        11.5 lb flywheel                
        3mm carbon\ceramic apex seals, Lanettis         
        port and polish,                
        replace injectors,              
        replace fuel pump               
        Total:          [$ ?]

Roll bar,               [$250.00]
MOMO seats              [$1,200.00]
CFDF clutch,            [$500.00]
4.375 Ring & Pinion     [$500.00]
Racing Beat sway bars   [$400.00]
Slotted rotors          [$500.00]
Motul brake fluid               
Hawk Pads               [?]

Autocross Upgrades for ASP Class

Date: Fri, 22 Aug 1997 12:13:45 -0700
From: "Pollard, Monty"

I am posting this for Craig Nagler of Tri-point Engineering who is not a member of the list. Craig is selling one of the most incredible 3rd gen RX-7s I have ever seen as you can read below. Please respond to Craig at his E-MAIL address below. As this is a very serious car, I am sure he would appreciate serious inquiries only.


PRICE: $26,000

Electromotive Tec II Engine Management System
Greddy Intercooler
Tri-Point Cold Air Box with K&N Air Filters
Tri-Point 8 lbs Aluminum Flywheel
Tri-Point Street/Track Clutch/Pressure Plate Assembly
3" Stainless Steel Exhaust System with Borla XR1 Presilencer and carbon
    fiber rear muffler.
Penske Double Adjustable Coil Over Shocks
2 =BC I.D. Race Springs
Tri-Point Black Delron Suspension Bushings
Tri-Point Adjustable Blade Type Sway Bars
Sparco Seats
Momo Steering Wheel
Auto Power Seat Belts
2 Sets 17x10 Wheel/4 HRE/4 Complete Custom Wheel
Hawk Brake Pads
Greddy Strut Brace
Misc. original and spare parts

              2ND IN PRO SOLO ASP YEAR END

Drag Racing Mods

Date: Sun, 20 Jul 1997 23:56:30 -0500
From: "Kevin T. Wyum"

Well, I think the roadmap is complete. There are now two 3rd gen RX7's within 5 miles of me that will run high 10's in the quarter, not including mine. The same work was done on both of them and they are both producing what looks like very similar results. Beat a mid 10 second turbo regal last night in one of them. Boy did I have a big smile. Anyway here are the parts that were used. Nothing has broken or had any parts failures.

Ported motor with 3mm seals  (one has this)
Custom intake
ASP Exhaust (I still can't figure out why it's too loud) I must be deaf
Air separator tank removed
Non sequential turbos
Super 50 wheel turbos
Centerforce DF clutch (CFDF)
Bleeder valve for boost
Heated O2 sensor
Crane HI6
11.5 plugs
Purple motor eater for fuel control and a gold one on the other car
Street legal M & H DOT tires D20 compound
Leaded race gas 114 or 115 during high boost

The third car is mine and I'm not telling what's done to that just yet. So the above should be considered the right way to do it if you are looking to get it right the first time. I've still never seen a car blow a motor if it's set up right.


Date: Tue, 28 Oct 1997 02:21:12 -0600 From: "Kevin T. Wyum"

BTW for all you guy's who want to improve you're 1/4 mile times by at least a half second I have a little trick for you which I never used, because I never needed to, basically kept it as a silver bullet in my pocket if I ever really needed to beat somebody. Change rear gear ratios. With a stock motor etc. it would have dropped my time to a ~10.5 on street legal tires. I have made two sets of them, very expensive for a gleason torsen hypoid differential and very hard to find a place that can custom manufacture it. Took me months to find a place that could do it. It's a 4.77 to 1 ratio, I can have nearly any ratio made so... Price unfortunately will be about $2500 if anybody wants a set with about a month to manufacture. These are hardened race parts. Your cruising RPM should still be reasonable at about 60 to 65 MPH at 3000RPM. The larger your rear tire the lower the RPM. Should actually help a lot for any road racers out there as well since it is not a visible mod and will increase acceleration dramatically out of corners etc., 5th gear becomes usable although you're top speed will drop from 180+ to 165 or so depending on the tire height you run. Anyway this should explain why I was not worried about matching or beating Adams previous times, I could have come close with a stock motor. So if anyone has questions about this Email or call etc.

Now what did I spend all year doing? Obviously everyone know about the turbo deal, Some prelim's on the turbos are interesting though. I've got a 3" exhaust with a Dynomax Ultraflo and a Supertrapp on it. These turbos are louder than even the non sequential so a muffler is a must, probably Borla or equivalent. I will probably change exhaust housing on mine to change the spool characteristics since first impression is that it may be too tight. Nice part about this setup is that you can change turbine housings for $150. Some pictures of the engine bay will be up soon, it looks pretty trick, far better than any single turbo setup I've seen plus the spool is amazing. I can produce 2 psi of boost by just revving in nuetral to 5000RPM. Hit 10 psi by 2500 to 3000 RPM at 1/2 throttle in 2nd or 3rd. I've got about 200 street miles of the ~ 450 break in I need. So far so good. Looks like about $5000 for the kit as a guess, sold through either Trev or myself. Kits are a few months off yet since jigs and copies need to be made. About $600 to $1000 extra if you want the ceramic ball bearing turbo's like I'm using. There are new like the Garrett race version using the bearing as a thrust surface, not only the axle support.

I did pull the motor out early this year since I knew I was going to wait a few months for the turbos. So no it is not a stock motor anymore. What did I do? Trick new half bridgeport. When I say half I mean the overlap is lessened to make it more street and road race friendly. All of the stiffer oil seals etc were used and the 3mm single piece carbon ceramic apex seals. I also decided to open up the exhaust port downward as much as possible to begin the exhaust cycle sooner to minimize the contamination of the intake charge and to increase the pulse duration to the twin turbos. The power cycle is pretty much done before that point so there is no reason to keep it closed off. All of the assembly and porting was done by Brian at Mostly Mazda. The idle is very cool. If you want to talk about intimidation, this is it. Idles about 1,500 with a very obvious and much slower and deeper than a NA bridgeport sound. Brrraappp Brraapp Brrrrappp. Sounds like a top fuel car. I'll get plenty of races on the street by saying something is wrong with the car, listen to the idle. Heh.

Also went with the 8.5 lbs. Aluminum flywheel and again a CFDF clutch. The launching is not an issue nor is the street driving with the bridgeport. From a stop it's no harder than stock to get moving.

As for the fuel system. Went with a Motec M4 from Brian at Mostly Mazda again to control everything. These things are damn expensive but very cool. Why does it idle so rich? Who cares. Pull out the laptop and change it. Automatically data logs all sensors everytime you drive. It saves the most recent hour on the ECU which you can download and view in number, graph or simulated dash form in real time. If you want to spend more it will keep track of your speed and gear as well using the ABS sensors. For fuel delivery I'm using 6 850cc injectors with all of the stock fuel system gutted except the stock tank and pump which is used via a in car switch for highway or street use and a second 12 gallon tank with huge SX pump and -10 braided line to the front of the car. The Fuel rail fittings have all been cut off and - 8 AN fittings tig welded on with - 8 lines supplying each rail which removes the bottlenecks in the stock fittings etc.

Intercooler is the same size but the inputs from the turbos are different. The front turbo feeds the top of the intercooler and the rear turbo feeds the bottom of the IC through separate tubes. It looks very nice.

Most of the other engine bay components remain the same as before. Coils moved, air intake, etc...

Suspension changes that have been made. Custom trailing arms from Mostly Mazda again which it seems a third party gave to Adam after the fact and claimed he developed it. (Funny) Went with coil over adjustable ride height on every corner with 600lbs springs on front and 500 lbs on back. Stayed with the GAB super R's and managed to get everything fitting using the Complete Custom 17" wheels.

Front is 17 x 10 and rear 17 x 11. Running Hossier Road race DOT's 275/35/17 front and 315/35/17 in back and a 3 piece speedway front swaybar. Also have Willwood superlite brakes up front.


> Reigning Performance of Austin, TX. claims they can upgrade my 93
> touring to around 490HP for around 8-9k.  That's with a single turbo and
> upgraded exhaust, intake, computer, intercooler, fuel system, I believe. I
> think the owner said 14 pounds of boost.  Doesn't seem right to me, not to
> mention, I would never want to upgrade my car to that kind of horsepower
> in the condition it's in now.  They're not including any sort of
> street-ported engine, so reliability is definitely not going to be part of
> that equation.

I agree that these HP numbers do not seem right. That is way optimistic. But you could contact the shop and see if they have dyno sheets to back these claims up.

The costs also seem way low. Gordon provides some alternate pricing estimates. I modified the intercooler high range as there are several popular ICs that go for about $1500. Gordon had listed this as $1000+.

I would add that Gordon's estimate for the fuel system might be a little low, if you were to include the fuel pump, regulator, new lines with AN fittings, cleanable filter (e.g.- Canton), new injectors, etc. (This is probably one of the areas Gordon refers to as important things not included).

If the shop does include all of the parts required, for the price given, they are probably skimping quite a bot on quality parts and leaving things out.

Also, as Gordon said, the labor will be a LOT. --Steve

Date: Wed, 06 Oct 1999 17:05:17 -0500 From: Gordon Monsen (

That's a minimum of about $7-$12,000 in parts alone and note that this is somewhat bargain basement on the hardware and doesn't include many things I think are important in such an upgrade. I list the parts costs below as ranges.

Normally, labor is two to three times part costs. -gordon

Part Description          Costs:  Unit price range          Running total
Single turbo                      $2,000  to  $3,750        $2,000  to  $3,750
Exhaust                            1,000       1,250         3,000       5,000
Intake                               400         500         3,400       5,500
Computer                           1,500       4,000         4,900       9,500
Intercooler                          850       1,500         5,750      11,500
Fuel system                          500         750         6,250      12,250
External wastegate                   300         550         6,550      12,800
Boost controller                     350         N/A         6,900      12,800


Date: Wed, 6 Oct 1999 21:00:25 GMT

Wow, that's cheap for the fuel system. I spend over $1k alone just on parts plus another 250 on the fuel pump. I did all these work myself so labor was cheap. :-) Single turbo looks a little pricey but I'm assuming you're including the exhaust manifold and piping from turbo to I/C. custom downpipe will probably run about $500 for stainless steel. You might also want to get a BOV ($200-250). The list can go on and on because you'll need EGT, boost, fuel pressure guages, upgraded ignition system, a/f meter, better clutch, stronger differential,.....etc.

RiceBoy Mods

Date: Tue, 28 Jul 1998 12:27:45 -0500
From: "John Wise"

Stage I
For the kid who's making the best of the economy car his parents gave him.
- ----------------------------------------------------
Fog Lights
Clear Corner Lens
"Performance" Stickers
Side Marker Lights
Seat Belt Pads
Carbon Fiber Shift Knob
Carbon Fiber Pedals

Stage II
Getting addicted to these AWESOME modifications to his pimpin' ride
- -----------------------------------------------------
2nd Set of Fog Lights
Resonated 5" Exhaust Tip - It looks 'fast', now it has to sound 'fast'
MORE Stickers
Cut Springs
Ion Blue Headlights
Paint Interior Pieces White or such
Colored-Faced Gauges

Stage III
Now the car needs to look like its Japanese counterpart overseas
- -----------------------------------------------------
Intake (to get that 'performance' sound)
Japanese-only Model Emblems
Supra Spoiler
Clear turn signals
Single Windshield Wiper
Steel mesh grille

Stage IV
Added flash!
- ------------------------------------------------------
Polished Muffler with 5" Tip
Clear taillights
Strut Tower Brace (to add to the engine compartment shine)
Paint rear drums
Biggest Wheels possible

Stage V
The elite of the boys
- -----------------------------------------------------
Massive 'Team' Sticker that goes over at least 2 body panels
Chrome or color out engine components
75hp Shot of N2O (el cheapo fast before sensible mods)
And to finish it off...a Horrendous Body Kit

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