Liam Fitzgerald

Hi guys, i've recently bought my first rotary (my 8th mazda now...). A 1990 FC Savanna Turbo. I know a decent amount about rotaries however i do have a few questions, i've used google and i've found similar queries that don't quite describe my kinks.

1. The FC hesitates to start after being warmed up, it cranks for between 4 and 6 seconds before wanting to start, sometimes i have to hold the throttle in to get it to start (which i found weird being efi and all). I know all about the leaky injectors & my compression is good (87psi in front, 86 psi in rear. pulses are consistent). Should i be at all worried about this? I know a compression test doesn't tell you everything.

2. - when i cold start it, it fires straight away however i have to keep my foot on the throttle to prevent it from dipping below 1k rpm and dying. I have a small exhaust leak just behind the cat, is this the cause of my issue or is it a tps problem or something else?

3. - my headlights do not pop up & low/high beam do not work, however parkers do and all of the switches & lights on the dash work. I've checked all of my fuses, what is the most likely cause of this and whats the best way to go about fixing it?

4. - Servicing it, im yet to change my gearbox fluid & a few other small service items.

Spark plugs - Are twin spark plugs such as iridium plugs worth running or should i just stick with the standard type NGK R plugs?
Transmission oils - I've been told only to use Redline Shockproof 75-90, as i do tend to drive my cars quite hard. Is this the only type of oil i should use or are there better alternatives, price is not really a concern so long as they are not over $120 per change (keep in mind i change my trans oil every 20k).

5. I have a throw-out bearing that is starting to go and will need to replace it soon, at the same time i will be swapping the clutch out for something a little better. I was thinking of using the direct clutch cushion button clutch as i want something that is agressive but also easy enough to drive daily in traffic without ripping a skid everytime i let the clutch out (i dont need more cop attention). Is this a good choice or is there something that would better suit my purposes?

6. I will be changing the fueling system out for a bosch 044, high pressure fuel rail & 1000cc injectors. I've been told if i change the fuel pressure to exactly 64psi & the boost to 12 pound i should see noticable gains, has anyone else got experience with this? I've owned turbo vehicles before and i know all about the gains to be had in changing the boost, but i've never stuffed around with the fueling systems apart from swapping out fuel pumps. On a side note are the electronic boost controllers with gear by gear boost worth the money over a bleed valve?

7. Alloy radiators with twin thermos, are they worth doing for the FC or is it just worth leaving the original system intact?

Sorry if any of this has been covered previously, I have snooped around a few rx7 forums now but i've not found these exact issues. Any help would be great, Thanks guys!

satch

iTrader: (1)

3.) Your headlight switch is likely damaged and perhaps the headlight harness as well. Locate the headlight relay in front of the radiator and ground the White/Blue wire in the 4 wire plug and see if the lights come on (not pop up but come on).

RXSpeed16

iTrader: (41)

1. hot start issues are common. Usually due to leaking injectors or low compression. Your numbers aren't great, but I wouldn't worry much about it as long as they are even.

2. Sounds like someone has incorrectly adjusted or removed the cold start thermowax. Once warm, you don't have to hold the throttle to keep it running, correct?

4. Stick with standard or platinum versions of the NGK plugs. BUR7EQ and BUR9EQ, add a P to the end if you want the platinum version. Platinums last a little longer but cost more.

Transmission oil- 75-90 works. I currently I'm using Redline MTL. It is a bit notchy when cold, so I'm going to try Neo on my next change.

5. Not sure exactly which clutch you are talking about, but any street/strip or level 1 upgrade clutch is going to be enough to hold the power made by a car with the stock turbo. Everyone has their own threshold for 'streetable' but I haven't found anything with an unsprung disc to be worth the tradeoff in driveability.

6. That suggestion is just all kinds of wrong. Whoever told you that deserves a swift kick in the groin. I'm sure you have a much funnier slang for that, but I think the intent is clear. Gear specific boost in't very common because there are no stock sensors for current gear and doesn't have much benefit outside serious drag racing.

7. Can you elaborate on a "twin thermos" radiator? A picture would help too. Aluminum radiators are a good upgrade from a cooling capacity and reliability standpoint.

satch

iTrader: (1)

And there are relevant fuses not just in the interior fusebox but the engine fusebox as well. The Head fuse and Retractor fuse are both in the engine fusebox.

Liam Fitzgerald

I will have to check that out tomorrow, do i need to leave the switch in the "on" position before grounding the relay? Also which relay should i ground as there are 4?

I've used a test light on ALL of the interior fuses, they all work fine. I checked the retractor & head fuse in the engine fusebox and replaced both with new ones to be sure, no luck. Parkers come on in the head lights, dimmer works, just low/high beams do not engage nor does the headlight pop ups (the pop up switch just above the headlight switch doesnt do anything either).

Is there a wiring diagram available for the headlights? and an interior fusebox diagram in ENGLISH as my cover and diagram is in japanese....

AFAIK 90psi is standard? car has almost 100k on the clock, wouldn't it be pretty normal?

After 1-2 minutes i can leave it to do its thing, its just the initial startup when its stone cold.


So should i stay away from oils such as penrite and just stick the the top shelf stuff or is the lower end stuff alright?

Cushion button clutches give the gradual feel of an organic clutch but the bite and clamping force of a button clutch, theres a small sandwhich plate that acts as a spring (or buffer if you will) it sits inbetween the front and rear of the contact plate, other than that its a typical button clutch.

Is that just the boost controller or about the entire fuel setup?

This is the setup i'm talking about.

RXSpeed16

iTrader: (41)

It's normal for an engine of that age. But you should think about putting money away for a rebuild if it is the original engine.

That pretty much rules out TPS adjustment. It's the thermowax system. Often people remove it thinking there is some performance benefit and just end up ruining the car's ability to run on its own.


Sorry, not familiar with that brand. FWIW, at the factory, they used "lower end stuff" and I'm sure a lot of that fluid stayed in many transmissions for much longer than 20k. Personally, I use a synthetic because it's not something that needs to be changed that often and the small premium in price is worth it.

I guess it comes down to your power goals. Are you using the stock turbo?
I'm using an ACT street/strip clutch rated for 330ft-lb and it is perfectly streetable. Pedal is a little heavier than stock, but it is no problem starting on steep hills at sub 3000 rpm.


I'm talking about that particular fuel setup. It might make sense if you had a 500 whp turbo and a programmable ecu. But those are very critical details to leave out.

Your strategy is correct though. You need to increase fuel delivery of the pump and injectors and a way to control it with an aftermarket ecu. Then you increase the boost.


Electric fans allows for finer control of the cooling fans but fans only affect cooling when idling or at slow vehicle speeds. At higher speeds, the air being pushed through the radiator is much more than the fans can move and they actually become an obstruction to cooling. Bottom line: If you don't have an issue cooling at low speeds now, there isn't anything to gain by upgrading.

Liam Fitzgerald

Yeah i've been putting aside $25 a week in an account for when the motor goes, i'll be doing the rebuild myself when it happens, will also likely move to bridgeport.


Any cheap-ish way of fixing/bodging/replacing this?



Forgot this isn't an aussie forum, penrite is a domestic brand and is pretty much top of the "Affordable" type fluids before you start paying for martini/royal purple type stuff.


I'd like to see around 320rwhp, maybe 350. The stock turbo will be maintained as its well hidden and whilst im still on p's i'd rather a cop not know where to find the turbo/not know what he's looking at.


So just updating the fuel pump is the best idea? the bosch 044 is the common upgrade here in australia



Yeah i'm not having cooling issues at low speeds right now but my radiator does need replacing in the near future so i thought i'd ask if it was worth doing when i did the radiator, i'll be spending the small premuim for an alloy radiator (double/triple core) if its worth doing. Some cars it makes no difference.

misterstyx69

iTrader: (142)

That Picture of the rad shows the inlet/outlet on the left side of the Rad,where as on an FC the inlet/outlets are on the right side.
You could "technically" run that Pictured Radiator BUT you would have to extend the hoses and make them custom fitted to do it.
I'd look at aftermarket rads that are made for the FC,that just slide in and bolt up...like KOYO.

Liam Fitzgerald

Thats a random google pic, not an actual picture of something i have. It was more to illustrate what i was talking about.

Evil Aviator

Sounds like typical low compression to me, although I am not a mechanic.

"115+ is like new, 100-115 is healthy, 90-100 is getting weak(1 year or less in most cases) below 90 could blow at any moment."
Source: Rotary Resurrection home of the budget rebuild.

Red Line Shockproof is more for those who inflict serious damage on their transmission on a regular basis, such as you see in the Tanner Foust Youtube videos. If this is the case, then you should probably change your fluid every year, or every race, depending on the severity. If you just drive on the street with occasional autocross or mild drag racing, then you can use a 30 month / 48,000 Km change interval as per the Unique Driving Conditions in the factory service manual. If racing, then you should go by what your fellow racers have been using, but I would think that 75W-90 Shockproof is too light, as racers in my country usually use 75W-140 Shockproof.

Red Line MTL is 75W-80, which is better suited for colder environments. Most people would be better off with Red Line MT-90 (75W-90). I have tried several brands of Ester and PAO-based synthetic oil in the transmission and they all worked just fine. For the last several years I have used Red Line because I can get it for a good price, and I am of the opinion that Ester base stock offers better protection than PAOs.

I have the same opinion as RXSpeed16, in that the transmission oil is not changed very often, so I have no problem spending more money on a good synthetic oil that improves shifting and helps protect the transmission better. However, any oil of the proper specification will work fine for every day communing, just as long as it doesn't eat away the synchronizers.

That is up to you. Just make sure the clutch has a torque rating appropriate for your car.

Your car has a "mass airflow" engine management system. It works by measuring airflow and injecting fuel based on a pre-set table. The fuel is metered by time (milliseconds), assuming 34-40psi pressure and 550cc/min fuel injectors. The computer does not have the ability to sense changes in fuel pressure and fuel injector size, so if you increase them the computer will still use the original milliseconds from the pre-set table, which will flood the bejesus out of your engine, bogging down acceleration, and maybe even killing the engine. Therefore, you can't change the fuel injector size or fuel rail pressure unless you use a reflashed ECU like the ones sold by Rtek, or install an aftermarket fuel computer like the Apexi AFC, or replace the entire system with a programmable engine management system (EMS)such as those made by Haltech, Microtech, MoTeC, etc. No, you can't attach an OBD whiz box to change the settings because the ECU is not OBD compliant, sorry.

The Bosch 044 is a good idea. You can usually run up to about 10psi boost without an aftermarket fuel controller, depending on your environment.

Yes, electronic boost controllers are far superior because they open/close the wastegate exactly when desired. Manual controllers allow the wastegate to meander along slowly, which adversely affects performance. Note that most programmable engine management systems include an electronic boost control function of some type.

Use the 89 FSM here:
Foxed.ca - Mazda RX-7 Manuals

Given that 100% of the FC RX-7s in your country are turbocharged, and there is an intercooler quite plainly jutting out of the bonnet, either the cops in your country are complete fools, or you are a complete fool to think that they will not know that the car is turbocharged.

The OEM radiator is one of the few substandard parts on the car because it has cheap plastic end tanks that tend to crack and rupture. I would highly recommend replacing it with an all-aluminum radiator. The cooling system performance is binary, in that it either works or it doesn't, and more cooling capacity than needed will not make the car any better. Depending on your engine output and climate, you can use anything from a basic Koyo drop-in radiator, to a Ron Davis racing radiator, to a custom racing radiator. The OEM fan is actually pretty good, but the fan clutch is pretty expensive to replace so many people convert to electric fans when the clutch goes bad. As mentioned earlier, the fans are for low-speed driving below about 55 Km/h. Either dual fans or a single large fan are fine, just make sure to use puller fans rather than pusher fans, and most people find that 2,800 cfm or more works well for street driving. The shroud in your picture isn't designed that well because there is little to no stand-off in the corners. Note how this high-quality racing radiator shroud has about an inch of stand-off in the corners so the air can flow better:

tbledsoe11

Probably in the right direction with whats posted earlier ^^^

Liam Fitzgerald

oh well, guess i'll be going bridgeport sooner than i thought.



I cannot afford a haltech/microtech unit for some time. Apexi PFC's for an rx7 are rare as hell here aswell. I'll definitely be getting an electronic boost controller, any recommendations for which one i should use? I have a bosch 044 here ready to go in, just need to find the time to do it.


We get both of the N/a models (s4 & s5) here. And most cops have no clue what they're looking at unless its in thier face, i have sanded off the lettering on the shroud around the intercooler & last time i was pulled up i claimed it was simply an oil cooler, since they could not see the turbo they believed me and went on thier way, you'll find most australian cops are like that.

I guess i'll be looking into changing the radiator setup soonish as i know the rotary's literally die from being too hot or too cold.

Evil Aviator

The stock turbo is too small to work with a bridgeport. A bridgeport will also require an upgrade to a standalone EMS or a downgrade to a carburetor intake system, appropriate tuning, and being a high-rpm engine it will require balancing, clearancing, carbon or ceramic apex seals, hardened/locked gears, some other modifications, and a high-rpm flywheel. I know that the internet makes it sound like you can make a high-output bridgeport engine with a few swipes of a Dremel tool, but this is not the case.

If you are short on money then a home-made manual controller may be a better option. Electronic boost controllers are rather expensive. Parts and labor are less expensive in your country, so I would recommend checking with your locals.

I forgot that there was a very limited edition of Sports models. I am not aware of any S5 NA coupe models sold in Australia.

Well, that settles it, your cops are complete fools.

All automotive engines are like that. The 13B just has a little less tolerance for it.

RobbyWally

iTrader: (2)

For what it's worth, warm starts tended to be troublesome for my #2 vert until I settled on the following based on older forum posts. For dead cold starts, I start in Neutral and allow the ECU mapping to do its thing with the fast idle. Anytime the engine is warm or hot, I start in gear to bypass the ECU mapping for starting. Don't know how this applies to Aussie-equipped FCs. Hope this is useful for you. BTW, my vert is all stock with all the original US 49 state emission controls. Cheers!

RobbyWally

iTrader: (2)

Have you checked / changed all the vacuum hoses? Don't mean to insult by suggesting such a simple thing. But you do say you are new to rotaries. You asked a lot of good, specific questions in your original post. Maybe other posters assumed you had already addressed the possibility of vacuum leaks. Since no one else has mentioned it, figured I'd throw it out there. Cheers.

Liam Fitzgerald

I've not been through ALL of the vacuum hoses as of yet, been quite busy with family and such with christmas coming up and everything.