s1mpsons

iTrader: (5)

RX7Club,

I recently bought a '93 RX7, my dream car much like the rest of you, from rx7club member pincusa (Aaron). The car is great but, just like almost every RX7, she needs some work. I realize "searching" is my friend on RX7club. I have, and will continue to, search any and all issues with this car. I wanted to created this thread as a journal of the technical life of the RX7. I also wanted to use it as a means of conveying my issues to KNOWLEDGEABLE member who can offer help, advise, and direction. Here is a quick breakdown of the car as I have come to know (Note * means the mod/part/service was performed during engine replacement 5k miles / ~3 years ago).

Basics:
-Base model
-Black on tan
-5 speed manual
-104K chassis miles
-4 owners (I am #4)
-No accidents or rust

Engine/Transmission:
-Mazda re-manufactured from KDRotary *
-Aluminum flywheel *
-R1 dual oil coolers
-Koyo aluminum radiator
-Aluminum AST
-Turbos 'rebuilt' (previous owner purchased three sets of turbos to get two good cartridges. Shafts have minimal play and do not smoke) *
-Apexi intakes
-Racing Beat cat-back dual exhaust
-Downpipe (pre-cat only removed)
-New 5th gear synco *
-Installed a stiffer lockout spring *

Maintenance:
-New coolant hoses *
-New silicone vacuum lines *
-New fuel hoses *
-New fuel filter *
-Oil changed every 2K miles
-New plugs just installed
-ATE Blue brake fluid
-Diff and Transmission fluid (non-redline)
-New Battery

Chassis/Suspension/Brakes:
-New rear pillow bushings
-Tokico adjustable shocks *
-Rebuilt front calipers
-R1 strut brace

Electronics:
-Apexi AVC-R boost controller
-Boost gauge
-Sony CD headunit

Exterior/Interior:
-R1 front lip
-R1 rear spoiler
-R1 seats
-99 spec tail lights


So now that you all know what we are dealing with below is my plan so far as to what needs to be addressed (in order of importance). Please comment on any or all of these issues if you feel your information can be helpful and constructive.

1. Tune the boost controller
I have read 2 write-ups on how to use the AVC-R. Everything I read seems fairly basic, however, that makes me even more worried. Especially when the writers briefly note the fact that if your not careful this could all blow the motor. What specifically do I need to be careful of? I realize I still need to read through the apexi users manual for it before I go to town tuning it. Currently, however, the 9psi tune is less than ideal. What kind of boost limits should I aim for for a nice balance of power and reliability? There are a lot of ups and downs in the boost pattern. Nothing seems to have been smoothed out. Additionally, the car has trouble climbing high into the rpm range. Is this indicative of a more serious problem?

2. Install water temperature guage
The previous owner said the sender unit is already installed in thermostat housing. I have the remaining hardware to installed the gauge (wire, gauge, pod). I need to first locate the thermostat housing. Then I need to find a nice pass through in the firewall to run the wire through. Then I need to review the shop manual, which I downloaded today, to determine how to open up the A-Pillar.

3. Replace Oil Pressure Sender Unit
The previous owner also mentioned that the oil pressure sender unit was starting to go. He gave me a used extra one to try and install. I still need to search this issue. Any recommendations would be helpful.

4. Replace intercooler
After reading a very informative post found in the FAQ by jimlab (found here https://www.rx7club.com/showpost.php...5&postcount=6), it seems like it is definitely in my best interest to swap out the OEM intercooler for something a little more efficient. The SMIC type seems more appropriate than a front mount, since impeding airflow to the radiator with a FMIC would be bad for a temperture-sensitive car like the RX7 (as jimlab recommends). I certainly need to do more research on my options here, but I just wanted to get this down on paper. Idea's and suggestions here are appreciated. Please give a little insight as to why you feel the product you recommend is superior.

5. Catalytic Converter
The remain stock catalytic converter is something I need to address. As far as I know it has been on the car 15 years. Right now it seems to work fine. Perhaps I should swap it to a high flow unit before it goes bad. This is just an idea I am tossing around. What do you all think, keep in mind the car is in NY and requires yearly inspections (sniffer) which the car currently passes?

6. EM and Fuel System
Based on what you know about my car and where I plan to go with it, what are your opinions on fuel and engine management? Do I pose a risk of running lean or blowing my motor if fuel and EM are not addressed?

7. Exterior
Original paint is fair, but for this car to truly shine like I always dreamed, I eventually will need to address the paint. Might go 99 spec front end too when I deal with the paint.


Thanks for reading my write up on my new FD. If you can think of anything I am missing here that poses a reliability risk or offers huge benefits (with little cost, $ or reliability) speak up. I have a lot to learn.

Regards,
Jake
s1mpsons

Rx72Heaven

iTrader: (2)

No looks, good, i would start with a water gauge, and a new rad. The engine seems fine. If your going to mod it any more with a midpipe; to get rid of that nasty heat generating cat, get a PFC FIRST. i believe you may even need one now, to stay on the safe side with your intake and catback, it wouldn't hurt.

gracer7-rx7

iTrader: (16)

Regarding #6...
What do you plan on doing with it? Why do you think the existing system would not be sufficient?



The car seems really well sorted overall.

Rx72Heaven

iTrader: (2)

to be safe all id say is maybe a Fuel Pump, and thats it. And of course a PFC, but i said that in my last post.

TRISPEEDFD3S

iTrader: (26)

5.Bones High Flow Cat from RX7.com

6.Depending on your usage, most will agree with me that a good all around choice would be a reputable brand SMIC is definately the way to go. IE: M2/ASP medium, GReddy SMIC, etc...With that being said, if this is going to be mainly a street driven car, a FMIC will do just fine. Blitz units are the most user friendly as of install, but all will be around the same efficiency.

s1mpsons

iTrader: (5)

The car has a new Koyo radiator. So that's ok. The water gauge is definitely going in soon. I had the faq write-up on the PFC today. My question is, who can tune a PFC in the NYC area? I didn't think there were any FD specialist tuners around here. The closest shops are KDR (all the way in PA) and Peter Farrell Supercars (all the way in MD) and I have read that Peter Farrell Supercars doesn't tune cars they didn't build themselves.

Thanks for the suggestion. Does the Bones cat have a metallic substrate or ceramic? Since you are from CA, I assume the cat you recommend will pass CA emissions testing (and thus NYS testing as well). The car might see some autox, but thats after I get everything sorted out. The Blitz unit looked nice and seemed to fit right in the oem location. I assume you were referring to the stock mount unit, not the blitz fmic, right?

s1mpsons

iTrader: (5)

I haven't really figured out what I am going to do with the car. Autox would be preferable. I plan on continuing to autox my STi on a regular basis, however, the RX7 is too much of a pure sports car to never go 10/10ths on some type of course. I don't think I have to ***** to track my RX7 though.

I am going on jimlab's post. He seemed like a really knowledgeable guy and he thought the oem unit is not effective enough.

gracer7-rx7

iTrader: (16)

Not enough when running more boost. Stock fuel system is sufficient for up to 12 PSI.

How much boost are you interested in running?

What was that famous line... "Speed cost money. How fast do you wanna go?"

gracer7-rx7

iTrader: (16)

Bonez is ceramic. It is one of the more highly regarded high flow cats on this forum. You can search if you want to explore it further.

Most of what rx7.com (Rotary Performance) makes is of high quality. I have one also in the garage for when I want to go for the sniffer. Quality and fit is very nice.

s1mpsons

iTrader: (5)

I guess 12psi would be the highest I am willing to go (since that is pretty much the limit on the oem fuel system. I would want it to be an efficient 12psi though. I wouldn't want power or efficiency help back by the oem intercooler. Jimlab calls the oem unit a "heat sink". Does anyone object to that statement?

gracer7-rx7

iTrader: (16)

You might want get some dense foam (like for automotive upholstery) and seal the sides of the radiator shut to increase the effectiveness of the radiator.

Also, adam_c had a thread with some very good suggestions on where to place the temp sensor if you want to check it out. I think its in the Archives as well. If it is not, then check the FAQ.

You are correct, there aren't that many reliable tuners in the area. I used to live there. However, depending on your goals, you may not even need a PFC. In some ways you are opening up a can of worms with a standalone. The stock ECU and a few other plug-n-play ECUs do a good job depending on what your overall goals are and how much time you want to spend screwing around tuning and re-tuning.

Rynberg and Mahjik had some nice old posts on that topic if you want to do some research on it.

I had the Blitz SMIC in my first FD when I was in NY. Its a pretty good IC for 10-12 PSI. Fitment is perfect but doesn't give you a lot of room for growth. I'd probably say to go for a slightly larger one like the Greddy or PFS or Pettit so that you have a bit more room cooling potential. You can find them used at a very fair price.

The M2 / ASP ICs are very nice also but from what I've seen they present some fitment issues - especially with a larger IC like the Koyo - and are more expensive. I'd probably rate their performance potential as higher than the previously listed IC but it might be more than you need. I had a bitch of a time trying to install the M2 Large with my Koyo and eventually gave up after a very long day of screwing around with it.

s1mpsons

iTrader: (5)

Update: The oil pressure sender unit is starting to fail. The previous owner gave me a used replacement to try.

Thanks for the recommendations and references to original posters. I am going to look all of that up very soon. I think I will keep the fuel requirements within with limits of the OEM EM system for now. I guess that means setting boost to 11psi (to be safe/conservative).

DaleClark

iTrader: (55)

Sounds like you got a really good, solid car and you just need a few more things to be totally solid.

First, water temp gauge. Get that sucker installed pronto. If the sender is already installed, that's half the battle. The thermostat housing is to the left of the alternator, and has a radiator cap on top. Just go slow and take your time - route the wires cleanly, getting the wires for the sending unit into the cabin will be one challenge, might want to follow the vacuum line for your boost gauge and use the same path into the cabin. You can probably use the same power wires for the boost gauge as well.

Next thing I would consider is the FC thermoswitch. Mazda ran the FD pretty damn hot stock to try and improve emissions and fuel economy, but at the cost of engine life. There's a fan switch on the back of the water pump housing that tells the fans when to kick on. Stock is 108 deg. C - the FC (89-91 RX-7) thermoswitch changes that to 97 deg. C which is MUCH better. Run your car cooler, and your car will be much happier. It's about $50 or so from Ray at Malloy Mazda. Do a search for more info - I've done a pretty sizeable post on it in the past.

Your stock main cat should be fine - they work pretty well and last a very long time. That will also help keep your boost more stable. I'd hold off on replacing it with a highflow cat, especially since you have a stock ECU.

That's the next one - ECU. IMHO, there are 2 good options for you - either PowerFC or a chipped ECU. A chipped ECU is FAR simpler, and also cheaper - plug it in, you have a safe map for plenty of boost, zero work or fiddling required. The PowerFC drives much better and fixes many of the weirdnesses of the stock ECU (like the 3000 RPM hesitation) and gives headroom to literally run whatever you want, all the way to huge ports, injectors, and a massive turbo. But, it depends on how much you want to fiddle with the car - doesn't sound like you're a huge wrench-turner, you just want the car to run good and be fun, so a used chipped ECU might be the ticket. About $200ish for a chipped ECU, and a PowerFC is $700 at the low end.

AVC-R - check my website (www.clubrx.org) for my writeup on it. It's a great boost controller, but it has a pretty steep learning curve. With the stock ECU, stick to 10psi of boost and no more. That'll be .7 on the AVC-R's boost display. Just start with the settings low and gradually raise the duty cycle until you hit your target. If it's more than you need, you could probably sell the AVC-R, buy a Profec-B, and have some money left over.

Intercooler - DEFINITELY go stock mount. Front mounts are nice, but are a CHORE to install. I have a front mount because I got it for a song, but there's MANY times where I'd rather have a stock mount.

Don't forget all the other things that make the car go - you want good tires, healthy brakes, and healthy suspension as well. The engine is only part of the picture.

Have fun,
Dale

oo7arkman

iTrader: (2)

As far as the oild pressure sending unit, Ray Crowe at Malloy Mazda is the ONLY source you need to consider for buying OEM replacement parts. I just ordered one from him a few months ago. He is the cheapest, and you will usually have it in a matter of a few days.

PFC would be a good addtition, but not neccessary yet. Though I do reccommend it if you are going with a high flow cat. (FYI this also displays the water temp.)

A walbro fuel pump will suppourt most anything you would like to do power wise. If you want a little better pump, toss is a nippondenso. A new pump would really be all you need to do to the fuel system to never worry about it, but like mentioned above, the stocker will suppourt up to 12psi and keep you under the 85% injector duty threshold.

I have heard nothing but good things about the M2 IC's, but I have never had one. I did start off with the Greddy SMIC and I saw great intake temps even after running the car hard. Super easy to install and good volume.

I also have another suggestion, have the rear diff bushings been replaced? If not that is also another idea.

I am sure all the advice you are getting from these posts is more than enough to keep you busy. Good luck and congrats on your new purchase. Is sounds like a well taken care of FD.

s1mpsons

iTrader: (5)

DaleClark, your website is very helpful. Thanks for all the great write-ups and general advise on my project. I definitely gotta sort out the water temp gauge asap. The fan switch is also a great idea/ suggestion I would probably have never found out about through searching. Thanks!

I am a regular autox'er and I would never neglect the tires, brakes, and suspension. But thanks for the reminder. I'm going to look into a nice set of wheels (TE37's or RPF1's) with some RT615's. I am going to switch to a set of HPS or HP+ pads by spring. The car feels incredibly responsive and a pretty smooth ride (compared to my STi, that is) as is but there is a fair amount of body roll. I still need to do a fair amount of suspension research but I think some sways bars (or maybe springs) would be in order. The Tokico Illumina's aren't anything special but they are new and they work, so I guess I will leave them (unless Koni makes something bolt-in).

gracer7-rx7

iTrader: (16)

If autox is your game, search for and read posts from DamonB (mostly in suspension section). He runs in stock class and kicks ***.

s1mpsons

iTrader: (5)

Really? With Z06's in the game, the FD has little competitiveness in Super Stock. Street Mod II is the place for an FD. Thats a big-bucks autox class tho.

rotarymandan

iTrader: (15)

https://www.rx7club.com/showthread.p...C+thermoswitch
Here is a link to DaleClarks thread on the FC thermoswitch.
I would definately look into some kind of engine management. With your current mods an M2 ecu with the basic map would be good, although you would have to find one used as M2 isn't in business anymore. Another option already mentioned is a Power FC. If you did get a Power FC, it already has a coolant temp gauge and many other engine parameters can be monitered through the commander as well.

NissanConvert

iTrader: (1)

for what it's worth, i have the two gauge speaker pod with boost and water temperature.

I have the gotham racing pfc commander holder and on that I dsplay
-boost (mostly for peak values)
-IAT (if i know it's 0 degrees outside but the IC is heat soaked i don't do redline pulls)
-injector duty
-knock

That said, i wouldn't recommend using the PFC as your water temp gauge. Not only do you not have one yet, but having a proper gauge keeps it closer to your field of vision.

ZumSpeedRX-7

iTrader: (12)

looks good. for some reason, i always thought you had a FD. i always thought you were kind of lucky to have a STi and a FD.

you could always autocross the FD and rallycross the STi. thats what id do if i had both. luckily for my wallet i only have a N/A subaru that i only do TSDs in. i can barely afford one turbocharged project.

s1mpsons

iTrader: (5)

Update. I went through Ray at Malloy mazda and got a hold of a fresh oil pressure sender unit and a FC thermoswitch. I also found a nice deal on rx7club on an ARC stock mount intercooler to replace my OEM unit. Once I get this in I will move forward with the APEXi AVC-R boost tuning. The i/c looks like this:

s1mpsons

iTrader: (5)

Update: I am looking to get a nice set of performance wheels and tires. I am keeping autox in mind here even though I don't plan on being competitive with this car in SCCA.

I'm considering Enkei RPF1 17x8.5 40mm all around. Front tires will be 245/40/17 and rear tire will be 275/35/17 (thinking RT-615's or similar). I used the spreadsheet in the wheel/tire thread to calculate clearances. It looks like I will have the following tire clearance:

rear outside (in.) 0.22*
rear inside (in.) 0.58*
front outside (in.) 0.32
front inside (in.) 1.18

*To calculate the rear clearance I subtracted 0.6" to both rear outside and rear inside clearances which were calculated automatically in the spreadsheet using 245/40/17 tire measurements.
0.6 in = [(275 mm-245 mm)/2] / 24.5 mm/in

Does this sound like a nice wheel and tire combo for autox/street? I would like to here comments and suggestions on this set up. especially from people who have run similar set ups.

s1mpsons

iTrader: (5)

Also considering Rota Slipstreams 17x8.5 5x114.3 48mm. Front tires will be 245/40/17 and rear tire will be 275/35/17.

Rear Tire clearance, outside (in.) 0.53
Rear Tire clearance, inside (in.) 0.27
Front Tire clearance, outside (in.) 0.63
Front Tire clearance, inside (in.) 0.87

Any issues or thoughts?

Rebel-E

Sharp looking IC...

cabaynes

iTrader: (4)

Call Rishie at www.autornd.com and tell him you want a lightweight wheel for AutoX for your FD. He deals with Enkei wheels and a bunch of other brands and he knows what he's talking about when it comes to fitments. The RPF1 is a great wheel and your sizes would definitely fit, but it's always good to talk to a knowledgeable vendor. I'd also order from him, he's usually giving a bit of a discount to the RX7Club guys.

Charlie