I have had some good luck with Mazda's tech bulletin regarding intermittent misfires. Reference: Posts #42 and subsequent in this forum thread.

Great read! I am one of those "unlucky" people who purchased a high mileage one (over 120,000 miles). The price was right and I'm one of those who likes to work on my cars, making it my own. Some of the reliability mods were done, such as downpipe, hi-flow cat, RB catback, fluidyne radiator, new AST, silicone hoses, relocated fuel filter and boost guage. However, I have come across a few things that high mileage owners should be aware of:

1. Remove and clean all grounding points you can find. My car had some weird issues and this solved most all of them. 3 in the engine bay, including replacing the one from the UIM to the firewall, the one for the fuel pump (test your voltage while you're there) and the ones from aftermarket gauges. The previous owner had installed an air/fuel ratio gauge and my car would periodically throw code 17. I replaced the O2 sensor, triple checked my fuel lines and pressure, changed the fuel filter but in the end found that this gauge was poorly grounded.

2. Clutch Fork- I had immediately put in a new engine w/act clutch and pressure plate. The increase in holding capacity showed the weakness in the clutch's hydraulics within a couple weeks when the slave started leaking internally. I replaced the master at the same time. What I didn't know about these cars was the weakness in the factory clutch fork. It started to split right where the cotter pin is. Fortunately I felt the change in the clutch pedal before it completely broke. So if you're doing an upgrade clutch and pressure plate, spend the extra $100 and put in a new fork if it's still the factory one.

3. Turbo Control Solenoid - If you have slow boost response and/or no to little boost on your secondary turbo when starting from a higher rpm (above 4000), this is the place I would start. It's under the UIM (which most of you will know) and takes less than 2 hours to change. It felt like I had new turbos afterwards, response was short of incredible.

I'm sure I'll run into much more in the future as this is only the first summer I have driven this car. I would also like to say, that coming from owning a FC TII for 7 years and an RX-8 for the past 4, the FD is an entire different animal in terms of complication. I too am one of those people who like things simple....hard to be simple with a FD.

Thanks for the link! I do have an aftermarket grounding kit on the car but I haven't reworked that factory ground point in the back of the engine bay so I'll take a look at it.

I'm with Gordon, but you and I went to the same school.
A simple boost activated WI system is inexpensive, reliable, and can be installed in an afternnon even with pizza and beer breaks. I've had no problems with leaking, and the only clue to it's presence is the line running to the nozzle at the intake elbow...and two little LEDs for system monitoring. Along with knock suppression you get cooling and carbon control too. Based on my experience, I would add this to your list, which otherwise describes my car and philosophy pretty well.

Awesome Guide! , but following the whole making more HP craze .. I think you should add..

Rewiring the Fuel Pump..

Better grounds, cleaning the ground etc... help but it's a problem no matter what you do but I've heard of rare instances of guys like you finding a cure but I haven't experienced it my self. In my case I'll think it's fixed and a month or so of DD it may rain so I turn on the lights and wipers and OH DANG some hesitation at light throttle around 2500 to 3500 :(

Yep both the clutch fork and the clutch line will suffer on high mileage cars especially when you add the HD pressure plate.

Here's the list on a nice 52 miles FD I just bought:
bushings and pillow balls in the rear (front still good)
Fixed wiring to fuel pump (don't mess with wires) Car was doing a great and out of no where it wouldn't start. After ripping into the wires I found a cut off switch that had gone bad.
Removed stereo and sub
Removed auto unlock (was jaming up locking the car)
Rebalanced the wheels
Alignment
Tune
Oil change
Bled brakes



I can only go on my experience which is every single car I've purchased with water injection leaked, had really cheap wiring and was a nuisance. AGAIN just my exp. :) Every car I've owned and driven hasn't needed it and I track one of my cars pretty often in 100 degree weather (car only makes 350 max). The only frequent issue I've had is killing transmissions and I'm hoping it's as simple as keeping the fluid temps lower.

If I was worried about fuel pressure I'd install a pressure gauge (2 of 3 FDs I currently own already have 1) and check the pressure and fix the problem. Any sort of electrical issue with the fuel pump is crazy bad for this car and will also kill the pumps. Again I try my best to leave the stock wiring alone and it's proven successful and in the cars that I've owned with wires hacked everywhere I tend to find problems that require lots of time and effort to sort out. I've probably daily driven 50 or so FDs over the last 13 years.

I have a Miata for the track and bought my FD for a fun street car. It was a single owner all stock (except for stupid stereo and sub) CYM R1 with 101k miles on the original motor. I have begun a lot of the reliability mods, but am at a crossroad. I would like to autocross the car as well as street it. At the one event I did, I learned how bad the stock IC is. I've been looking at IC choices and have decided for my power goals of approx 300 HP a SMIC is what I would like to use. I was about sold on Petit's till I read your thread about the battery. I am no electrician, so I was not looking to relocate. What do you recommend for a good IC that would work in my roles.

At the autoex I also started to smoke under hard boost and it was suggested by a few guys that I install a catch can. I have been doing research and it looks like the correct way would be to have one with two lines, one from the oil filer next and another on the other side using one of the stock turbo oil drain lines. Is this what you recommend if using the stock twins and if yes, which line do I tap?

Thanks for your time!

My current mods are:
Koyo NFlow
RX7 wrapped down pipe
Apex N1 dual tip exhaust
Bones Hiflow
New Pillow balls
Eibach Springs
PFC (base tune) hesitates when tipping in the throttle tbd

Have to install:
Azeknight solenoids
New Silicon Vacume Hose

Can't figure out how to install:
Old M2 air box (new radiator conflicts with airbox

Intend to buy after your post:
1200 CC secondaries
Denso or Supra drop in
Maybe a FPD to throw in while I have the UIM out just to be safe

I intend after doing the hoses, solenoids, IC to take it down to Banzai for a proper tune.

There are only two ways to fix heat soak whether around town or auctocrossing and that's with a VMIC or FMIC and both of these will will help over all power anyway so it's not a bad idea to bite the bullet and go for it. If you're just going to auto cross the car and not track it I'd recommend an apexi FMIC (really well made and efficient and doesn't require cutting up the car) or the Rotary extreme VMIC. Both will probably require you to go with a turbo jeff style battery tray but that will also cut weight. Once you've installed the FMIC or VMIC take the car to a race fab shop and have them design some custom ducts (a must have) for your setup or do it yourself if you have the skills.

Regarding the m2 intake you may need to lower radiator using washers and bending the tabs on the radiator mounts to comply or breaking out a cutting wheel. The cutting wheel and the hammer get lots of use in my garage hehe :)

As for the catch can it's not needed (i get blasted for that statement and my remedy all the time) just don't go higher than 1/2 way up the dip stick (or 1/2 a quart to 1 quart low) but to be safe go with a high quality oil like amsoil, mobil 1, VR1 racing etc..... I have a catch can on my track car and the only time it catches anything at all is when I put too much oil in (I run my car most of the time at the bottom of the dip stick adding a little oil every other track session or so). If you aren't comfortable running the oil low (most are not hehe) then do a search on catch can installation lots of thoughts here but again I like the simpler the better as in leave everything stock and run your catch can in line with the stock system with a filter on top :)

PS Water injection will help with heat soak, detonation, keep the engine clean, etc...etc... but for reason already mentioned I like a simpler approach.

and one of the best reliability mods to date: get rid of the stock 3 piece OEM seals.

The cliff's notes version:

1. Don't get greedy
2. Keep it simple
3. Don't take short cuts
4. Don't assume aftermarket = better

So who are some of the best power FC tuners in the country?

So far I have had great luck on the stock ECU and never had any 3,000rpm hesitation. I actually prefer the safety precautions built into the stock ECU that I would lose with the Power FC (mainly the functional knock sensor feedback).

Only issues I had were when I went back to "stock" class Auto-x (stock everything with drop in K&N panel filter and 3 1/3" catback).

It over boosted in 3rd and above and cut fuel so it was a pain to drive on the street but worked ok in auto-x (1st, 2nd and only lower part of 3rd) and it had terrible 2ndary transition which led to poor power delivery- hard to race around boost spike on transition.

Now I am back to K&N panel filter, downpipe, catback and most importantly the awesome Hallman Pro RX boost controllers for wastegate and 2ndary prespool actuators for the perfect 10psi boost and seemless transition.


Mazda was on crack building a complex and sensitive sequential turbo system and not referencing boost for turbo control.

That's easy I'm not even sure if they are still made :)

Speaking of seals I keep hearing great things about the ALS seals so they could also be a strong contender as a reliablility mod as more data comes in.

You may of already tried it but you can adjust the wastegate and turbo actuator rods to correct some of those boost issues but it's a PIA.

My only experience is with Ray at PFS and he can flat out tune a rotary engine.

:nod:

Yup. Heard of PFS and the other guy I heard was one of the best is Brian from BDC. But I'm trying to see if there is anyone else that's a little closer to Oregon.

there's a number of alternative seals more durable than OEM, OEM being the best for longevity sake as mazda needed to be sure the cars would make it to the 100k mark rather easily. the 3 piece seals did get revised back to 2 piece seals and mazda no longer sells the 3 piece seals.

the engine is a big part of the reliability of the car, sometimes you get a car that was well taken care of, if it was abused and not well taken care of then the engine won't be long lived even if you throw as many reliability aspects as you can at it, it will help though. many people have gotten healthy motors and beat the snot out of them, others have bought garage queens that coughed up seals weeks after buying it while putting the car back to use, luck of the draw.

Say once you have achieved a reliable engine at 350RWHP, how do you address the Transmission and Differential to hold up as well?

there's too much information here but it's like a gold mine!

I know you mentioned getting the v8 thing out of the way, but is a v8 conversion a more reliable option? or does it also have its drawbacks?

apples to oranges, different power curves suit different people. most piston engines are reliable and make more torque, but they cannot rev as high or as effortlessly as a rotary engine can.

i compare these engines to 2 stroke dirt bikes versus 4 stroke bikes. they require engine rebuilds more often but they rev happily to the moon. a 4 stroke counterpart requires less attention to the engine, grunts when you apply the throttle but is limited and begins to fall flat if you push it too hard. race the 2 head to head and each has its benefits and drawbacks, but size to power ratio the 2 strokes actually came out ahead. my 1200cc triple 2 stroke jet ski puts out just shy of 150 crank horsepower, that is more than our daily commuter 1.8L 4 stroke car. 2 strokes and rotaries both have a bit if inefficiency to them at lower RPMs but they are not constrained by moving parts to rev as high as you can feed air into them.

smaller 4 stroke engines are becoming more rev happy, but they are also becoming more like rotaries, less torque but more power higher in the RPM range. they do have the advantage of adjustable camshaft timing which offsets some of that low end torque loss but they will always be limited by valvetrains.

Sub'd for later reading. I like what I'm reading so far...`

Change the fluids occasionally, maybe some bracing. IMHO, the FD transmission and differential are pretty robust. Now...if you're talking 4k launchs, all bets are off.
I'm only at ~ 300 whp and about 115k with no issues other than the original 5th gear synchro changed about 10 yrs ago. I have a friend who's putting down around 425 whp w/a single turbo (+ other stuff) and thrashs it pretty regularly on the track without alot of issues. It's got about 200k + on it now and I THINK he's changed the transmission once. That's not a bad record for ANY car.

Awesome post Fritz!

Good cliff notes Pete!

:D

The trans and diff can easily handle 350 on a street car so no need to worry about the drive line at that power point. 450 and up I'd start to worry though.

When it comes to the reliability of anything it's largely dependent upon the user/abuser and cars that see track work see nothing but abuse so the ceiling on abuse must be raised considerably. Track rats are basically the test pilots for any cars true weaknesses because the entire sport is geared around getting everything you can out of the car so they've learned through trial and error what works, what never will and what needs to be changed.

This forum can never have too much info :icon_tup:

I have no experience with V8s but usually when I see a car up on jack stands at the track it has a turbo attached to it ;)

What up? My car is still on jack stands. I take 1 step forward and 2 steps back LOL.

I'm heading to the FSR event in two weeks and will likely be in a twin turbo daily driver variety.

How's married life :icon_tup:

wow, hats off to you for doing this.... sticky?

Some will have you believe they eat housings in 3k miles or so like some other unbreakables. I just looked in my exhaust ports yesterday(pulled motor to replace clutch and install single setup) and at 17k+ miles with ALS seals the housings looked great. I rebuilt the engine with the original 61K mile housings and these housings now have 79K miles on them and looked great when looking through the exhaust ports.


But I USED to sell these seals so some think I have some vested interest in these seals and not just makeing people's experience with the rotary a lot better.:(


On a side note, great thread that is spot on. I am a huge advocate for water injection as a safety net. I dont think guys who DD their cars should tune for it, instead get a nice tune then add a simple small water injection setup for extra safety. You may lose a couple HP but you can beat on the car and not worry.


To those who dont buy the sub 40k mile cars(very few left these days), I am seeing these cars become more restoration/peformance builds than just performance these days. A new wiring harness is one of the best maintenance/perofmance/stress reducing things you can do for these cars these days.

I dont know how many people I have met over the years that are so scared to drive their FD due to believing the rotary is so fragile, I simply wouldnt own a car I was scared was going to break everytime I drove it. Do the simple stuff Fritz recommends and enjoy. This car delivers a thrill factor that is rarely matched by other cars, and for a fraction of the cost(initial purchase anyways :) )

because most people don't pay attention to the fine details. most importantly the fuel system, because a 15+ year old fuel system can't be expected to work as it did when it rolled out of the factory many years ago. first thing people should do when not knowing the history of the car is to focus on making sure the fuel system is functioning properly. this involves checking fuel pressure/voltage at the pump, change the fuel filter and last but not least service the injectors.

follow that up with the boost gauge so you can see if you're not overboosting.