the_berner

I have an FC-3S with the 13B and I have a couple questions about my car. First of all I need to know if there is a way to get my 13B to climb as high as my friends 12A in rpm's. His car will go to about 14,000 or 15,000 rpm before he shifts. He said it would climb higher, but he doesn't dare for fear of ruining something. Secondly, I read on mazdaspeed's website that if you buy performance parts from them you can't use them in a street car. Is there a way around that or is it even an issue? Thanks for taking the time and reading my questions and I hope to hear back from you guys.

87 t-66

iTrader: (133)

i'm calling BS on your friends 12a revving to 15k rpm. why do you think you need to rev that high?

dealers/manufacturers say you cant use the parts on the street to cover their asses...use at your own risk.

RotaryRocket88

iTrader: (7)

Even if you could take a stock 13b up to 15k RPM (and not destroy the engine), it would make no power at all. Don't confuse RPMs with horsepower/torque. Your friend is full of crap.

the_berner

It may be a bs story he's telling me, but I drove the car and it just goes forever and it has a sticker that he put on the gauge cluster that extends the tach's read out so the needle will still have something to point at, but at any rate it revs high. And as far as me wanting my 13B to rev that high, I thought that was one of the advantages to the rotory engine, was it's ability to carry such high rpm's. But anyways, I just want to have a powerful rotory engine and a fast car. It's already quick, but it's not fast. Plus, I'm usually not one to give inti peer pressure, but there's a guy around here with an '08 impreza wrx that talks a bunch a crap on my FC-3S and I have to prove to him that rotory engines rule.

87 t-66

iTrader: (133)

1. your friend is a retard if he drew extra numbers on his gauge cluster.
2. he is also full of crap.
3. you aren't going to beat an 08 wrx with your NA fc. i would talk crap to you too if you think you can.
4. as was already said, revving that high does no good if you aren't making more power.
5. if you want a fast car, do a turbo swap.

rx7vadim

"offroad use only"? I think you are new to cars and car modifications.

maybe 12a has a built, p-port.

rx7racerca

iTrader: (1)

Been said, but no way any 12A is reving to 14 or 15k. Redline on them was 7000, and unless it's a p-port there's no way it would breath much past 8 or 9k, even with a street port, and even if the fuel and spark could keep up. Mazdaspeed sells apex seals rated for up to 12k, which might be possible for a peripheral port 12a or 13b, but it requires a serious build and a perfectly balanced rotating assembly - big$$, and most people would just go turbo and make more power for the money. And a peripheral port is not a street car engine - people do it, but it's super loud, and smokey, and wouldn't pass smog anywhere there is some sort of emissions testing.

S5NA's redline at 8000, although there is apparently no fuel cut until 9000 - not that I believe they'll run to 9000 anyway; even with exhaust and minor intake mods, mine stops breathing or making useful power right at 8 (stock they're useless past 7800). Holding the down the gas instead of shifting is just an exercise in futility - sure, the revs will climb - slowly. Again, a street port likely could allow it to breathe and make power up to 9000. And it would be quicker, but it still wouldn't be fast, or as fast as a turbo. Turbo's are faster because they add the ingredient that is missing through most of the NA's rev range - torque. Revs and high-rpm HP are useful on the track, to a point, but torque wins the day in daily driving, and at the track in most cases. Just like an AP1 S2K makes 240 horse at 9000 rpm - but is geared so it's running 4200rpm at 65mph in 6th gear, because it makes no torque worth mentioning below 7000. So in daily driving, it feels lame unless you wind it out all the time.

rx7racerca

iTrader: (1)

Back to your buddy's supposed 15k 12a - since the stock gauge is about a 270* sweep, and reads to 8k, to display 15k, it would have to wrap right past 0 and about 1/2way around again. Which it wouldn't/shouldn't do, unless it's broken. And for the WRX - '08 was a relatively lame year (gained weight, about the same power as the previous year, got softer suspension) - but as long as your rotary is naturally aspirated, he's going to beat you like a rented mule in a straight line, unless you drop your 13B into a LoCost/Lotus 7-type chassis to loose 1300lbs or so of weight. You might be able to keep up with the Subby in an autocross or small road course (without long straights to let him leg out on you). But the driver is as big a factor there as the car, and your car would still need well chosen springs, shocks, tires, wheels, etc to do its best in a track setting. Point being, you are not going prove rotary's rule putting a 20 year old na FC up against a new turbo sport compact in a drag, and chances are the crap talking Subby driver wouldn't take the time or have the guts to take you on in the setting where the balance and agility of the FC might tip the scales your way.

the_berner

Thanks you, rx7racerca. I appreciate you honesty and your answers. While some of the other people on here posting replies were sarcastic and just gave me a hard time, you actually helped me. I know that a stock FC-3S is not going to beat a new Impreza, but I'm kind of stuck with my 13B for right now. I'm wanting to put a turboII in it, but I talked to another local rx7 owner and he got so fed up with swaping from N/A to turbo that he sold the car and gave up. He told me that it is a major pain in the you know what to swap it over. And that's just his opinion. I have quite a bit of automotive knowledge, but this is the first time I've ever messed with a rotory engine. I know I must seem ignorant, but I just don't know a lot about rx7's. I came here to ask a few questions and to get advice, but instead I get chastised. But forget that for now, at least someone is trying to help me. But I did find a turboII engine for my car and I'm going to try to swap it out even though I have been warned it would be quite a task. Thank you again rx7racerca.

RotaryRocket88

iTrader: (7)

My advice to you would be to work with what you have now, and learn the car inside and out. Click the following link for a good overview of how a lot of the critical systems work on an NA: http://mazdarx7.iougs.com/. The FSM & training manuals will also be invaluable tools (links on that page). If/when you're ready and have a few thousand dollars to spare, you can tackle a turbo swap. It's really not that hard when you know your way around the engine bay. The link in my sig. has it detailed out. And stop worrying about trash talking guy with a WRX his mommy bought for him. When he wraps it around a telephone pole you can have the last laugh.

rx7racerca

iTrader: (1)

I didn't see that you posted what year your FC is - S4 (86-88), or S5 (89-91), and base or GXL/Sport suspension (base=4-bolt hubs, softer springs, struts, and anti-roll bars, smaller brake rotors/calipers; GXL/GTU/Sport=5 bolt hubs, 4-piston upgraded brakes from TII, mildly firmer springs and thicker anti-roll bars). A turbo swap is much easier on S5s, b/c the harness doesn't need to be swapped, it's just about plug and play, assuming you're dropping in an S5 turbo.

RotaryRocket gives good advice as far as making the most of what you have.

Plugs - these cars eat them, and poor spark will hurt power and make the car even thirstier than it is normally. Same goes for the plug wires - if it has the originals, they may well be due for replacement - the stock Mazda ones are good quality but there are good aftermarket choices as well - I have a set of 8.5mm MSI wires, the main thing you want to avoid is the $20 cheapo generic replacements from Pep Boys or wherever.

Rotaries respond very well to simple things to help them breathe - eg., drop in K&N filter - don't just pop a cone filter on the end of the airflow meter, sucking in hot air from the rad and engine bay - any gains in flow will be more than offset by the performance hit that comes with hot induction air. If you want a cone, there are lots of writeups on getting fresh air to it, or locating it in the fender.

Exhaust - significant gains to be had here and lots of choices, so I'll just mention what I know best- if emissions aren't a problem, dump the factory cat and replace with the Racing Beat downpipe/resonator combo, or if emissions are an issue, use the RB downpipe and add a modern, performance cat and some custom pipe to mate up with the rest of the exhaust. Don't just throw on parts store brand mufflers - the Racing Beat na mufflers sound great and again free up a few ponies, without being obnoxiously loud, but there are lots of other quality mufflers. Just don't expect cheap ones to last - the heat and powerful pulses of the rotary eat cheap glasspacks. Moreso than piston engines, these cars seem sensitive to exhaust leaks - as in, even pinhole muffler leaks, or leaks in the piping and flanges, can cause a noticable performance and fuel mileage hit, and cause what feels like misfire or powerloss.

Going slightly beyond cheap and easy bolt-ons, these cars, turbo or na, run pig rich, which was Mazda's way of heading off apex-seal destroying detonation, but also hurts power as well as mileage. Depending on the series, you might be able to use the Rtek 7 v2 modified CPU to tune for more power and less fuel, or any number of standalone ECUs - with the caveat that on S5s, the electric Metering Oil Pump (MOP) that oils the side and apex seals is run by the ECU, so other than the Rtek modified factory ECU, programable ECU's usually mean using premix in your fuel, or swapping the front cover to S4 and using the mechanical MOP.

Suspension: good alignment, check for bushing wear. The factory struts on the upgraded suspension are actually pretty good, if they're not worn out; if they are, KYB GR2 are decent aftermarket replacement (stay away from Monroe Sense-a-Crap or generic), or for a bit more AGX adjustables, or for more still, Koni Sport adjustables (the rears can't be adjusted on the car with the Konis, which is a PITA - if I were doing the struts again, I'd go with Konis for the front and stay with AGX for the rear). Racing Beat or Eibach both make lowering springs that will firm up the handling, without going crazy on the stiffness or lowering it excessively (which will mess up the rear camber without more aftermarket parts to make it adjustable). A firmer front anti-roll bar is a decent idea, even with the sport suspension (which is a 24mm bar); upgrade the rear with caution, as these can be tail happy cars. The base rear bar is 12mm, and the sport suspension rear is 14. I've actually swapped out my 14 for a 12mm bar, and some racers just remove the rear. Unless doing a lot of donuts or ***-out slides is the objective, I can't see these cars needing more rear bar, but they're available, so people must be buying them. I like my car slightly loose (oversteer prone), but I do like seeing where I'm going thru the windshield, not the rearview.

In spite of this lengthy post, I've only scratched the surface with some food for thought here - read the FAQs and some of the stickied/archived how-to's, and get to know your car and figure out where to begin. Because FC's are a lot of fun out of the box, and even with a "slow" na car, there's lots to be done to improve performance, especially if you remember that any V8 Mustang can be fast 1/4mile at a time, but even box-stock a 20-year old FC is way more agile and fun in the turns

the_berner

Thank you guys again. I really appreciate all the information and plan to put it to good use. My RX-7 is an '87 base model I think, it only has four lugs. And thank you for explaining the issue with running rich. But I still think mine is running way too rich even with that explaination. It get's so flooded after I drive it that when I want to restart it I have to pull the fuse that controls fuel and crank it a few times to clear it out and then it will start. But hopefully I can repair that. And as far as suspension goes, I've already started upgrading that. I have KYB struts and Eibach proline springs all the way around. The main reason I started this thread was because I wasn't sure if I was going to swap to a turboII or not and I wanted to see what I could do to make an N/A monster if I couldn't. But the whole reason for the swap originally, besides power, was because I lost the waterpump in it and had to replace it. No big deal right? Not the case. Now the car burns coolant, oil and way too much gas. I've looked into rebuilding the 13B that's in it, but it looks like it would just be better to get a new 13B or TurboII. So, for right now the car is just parked until I decide which route to go. But thanks again for everything you guys have done.

rx7racerca

iTrader: (1)

Persistent flooding may be a sign of low compression and a weak engine - do a compression test (should find the procedure in the FAQs, can be done with a regular gauge, but requires a helper to crank while you watch the pressure pulses on the gauge to see if it's consistent on all three rotor faces). 2 Weak pulses in a row indicates a blown apex seal, one only a bad/sticking side seal, lower than ~80psi all around worn apex seals/housings. Will give you an idea of the general health of the motor, at any rate. It's not likely you have broken apex seals - it's rare on an n/a - but even though n/a's generally are long-lasting, like any motor they will eventually wear out.
Flooding could also just be a problem with worn or sticking injectors.