hyp36rmax

Okay guys im learning this car, i've been reading a few threads here and there and have visit a few sites such as www.fc3s.org

What i would like to know is what makes the 13bt engine tick and produce more power, as well as normal maintentance intervals and the like.

Here are a few specs that are on a particular car that im trying to help on.

*Full Racing Beat Turboback
*Racing Beat Plugs
*Racing Beat FCD
*Blitz BOV

Some issues on the car right now is smell of oil, the diff mount clunks everytime its shifted, the coolant meter on the center console beeps endlessly when the car starts, the passenger electronic window does not go down other then the driver controlling it on its side, need to tighten the bolts on the downpipe. a new thermostat, a new oil pump (?), shifter is very loose.....

So far what i do plan is probably a Koyo Radiator with Samco silicone hoses and new thermostat. Change the Diff Mount, fix the various electronics in the car (IE windows). add a short shifter...

What else should i be concentrating on? as for boosting, im aware that stock boost is at 5-6lbs of psi? (Correct me if im wrong) what is it capable of with stock turbo, full turboback, FCD, and some form of an Intake (i dont really beleive in intakes other then panel filters, I personally drive a 2004 Cobb Stage 2 Impreza WRX and in my case a panel filter is suffiecient up till 300bhp, this case is different since its a totally different car, school me rotorary guys\gals)? So what is a safe point to boost at? and what setting with AFR?

As for Engine management, i have been looking at the Apexi FC, rather pricy but looks like the king of the crop in terms of tuning the FC/FD, but right now i may just go with a Boost controller and maybe a AFR controller (keep in mind i would rather get the Apexi FC, but its the funds....)

My main point is i want to create an efficient light tune car, i would appreciate all the help i can get to achieve this....

Thanks,
Eiji

black_sunshine

Increasing efficiency (horsepower) can be done many, many ways. Firstly, if the car has a tired old motor, turbo, and all the supporting parts (around 150,000miles), it's never going to be efficient, nor is it going to last very long once the HP numbers start to rise. Rebuild the motor, turbo, and replace the fuel system (new pump and most likely injectors). Get it in "as new" condition before trying to make more power; it's expensive up front, but VERY much worth it in the long run.

Weight reduction. Easy to do, and it'll make the car handle better, and accelerate faster. That, and you don't need to increase HP to do it.

Smell of oil: Normally, these cars inject (well, more like a dribble) oil to lubricate the apex seals. They're supposed to burn 1 quart approximately every 3,000 miles (varies from car to car). If it's burning much more than that, it's probably time for a rebuild.

If the Diff mount is clunking, it needs to be replaced. It's a PITA to do, but it IS necessary.

If the coolant idiot light is coming on and it's got plenty of coolant, that can mean may things. First, check the coolant-level sender on the top of the radiator. When it has no connection or the coolant level is dropping below the sensor, it'll turn the idiot light on. If it ONLY does it when the car is running, do a pressure check on the coolant system to make sure it's not leaking anywhere. As a last resort, pull the spark plugs or the exhaust manifold and check for water in the engine (bad coolant seals). ONLY USE A MAZDA OEM THERMOSTAT! The others (stant) are nowhere near as good, and on a hot day, especially on a turbo, it WILL try to overheat if driven anywhere above "baby" level.

Replacing the oil pump (there's two of them; metering oil pump and the normal pump) is always a good idea.

If you're trying to boost anything more than 10psi (slightly varies from car to car; 9-12psi), you'll get slammed with fuel-cut. You NEED a Fuel cut Defencer, and even then, you still will probably kill the motor due to running lean. Band-aid fixes for this are upgraded fuel system and upgraded injectors, but they're just band-aid fixes; they don't solve the problem.

The PowerFC is a good piggyback, but why not just do a standalone? A boost controller is mandatory, and you'll HAVE to port the wastegate (or try to add an external one or replace the turbo with a S5 (89-91)) massively on a S4 (87-88) TurboII, or it's going to be boost-spike city after the turbo is allowed to breathe.

The stock air-box is pretty restrictive. I assume you mean a square fiber-element filter that's pretty thin. They're great, but why not just go with a nice cone filter? Oil/foam elements work wonderfully, and paper element/oil filters are equally as good. And you get to loose that stock air box.

I believe that with a good AFR controller and a boost controller, you can probably get somewhere around the 200-220hp range, though it would be inefficient. But if you upgraded to a more efficient turbo and intercooler (the stock one sucks), that number could be much higher.

If efficiency is what you're after, take the motor apart, rebuild it, have it ported (a "stage 2" street-port), upgrade the intercooler and the turbo, get 1600cc secondary injectors, a strong fuel pump (walbro 255), a rising-rate FPR, a standalone (Haltech, Wolf3d, Microtech) or a fuel-only computer (MegaSquirt, Haltech, Microtech....), boost controller... and then it'll easily be into the 400hp range. Of course, after it's all said and done, that's around $10,000usd....

Or you could just rebuild the engine, get a boost controller, Fuel computer, FMIC (isuzu NPR intercoolers work great), and build a hybrid turbo. I've read you can get into the 220-250hp range rather easily, and with some effort, 260-300hp. Anything more than 250hp and the turbo's exhaust side will be a MAJOR restriction (try a T04 conversion....again, around $10k)

That's all I know about this. Hope it helps!

hyp36rmax

Whoa! that is the most insightful reply i have gotten as of yet! i commend you on this because i am now going to cehck some of the things youhave mentioned, across the board i have gotten very simliar repsonse about the fuel pump and injectors. i have a q about the injectors what is the ballpark figure in terms of price and the size of them? will i be able to just goto a dealership and ask for it or will i have to go to a performance shop?

Any recommendations on type of foam intakes\filters? as well as what to port? other then the st port?

thanks,
eiji

GUITARJUNKIE28

rotaries like gas. period
compared to a normal 12-12.5:1 afr like on a piston engine, rotaries (under high boost) like the afr as rich as 10's!!!!! i try to go for 11-11.5:1 depending on conditions. of course, i still have closed loop for light load conditions.

i agree with just about everything black_sunshine has to say about this, but i tend to try and get away with a little bit more.

1) the cooling system is a subject of much debate. sooooo many people tell you these cars overheat soooooo easily, but bottom line is: if your coolant system is in good shape, it should be adequit for mildly modified engines (250hp or less). i think what leads people to be so paranoid about coolant issues is the damage that gets done as a result of overheating. rotaries aren't as forgiving as piston engines.
i have a summit 26X19 2 row radiator and an electric fan from a ford taurus. this does a great job of cooling the car off, but i definately WOULD NOT USE AN ELECTRIC FAN WITH A STOCK RADIATOR!!!!!!!!!!!!!
note: if you're tired of hearing that low coolant buzzer, ground out that wire that goes to the sensor on the top of the radiator. just make sure you check your coolant!!!!!!

2) fuel. a super afc and larger secondaries (720 or 850 maybe) should get you well into the 300 hp range safely. keep your duty cycle low (<85%) to avoid overheating the injectors and dyno tune it right away!!!
a rising rate fuel pressure regulator would also be a good idea.

3) you've got exhaust taken care of......i blew so many gaskets at that junction from the turbo to the downpipe that i quit using a gasket there all together. mine seals fine. one tip: i use star style lockwashers instead of split style. i've had better luck with them not coming loose. it's a good $.39 mod.

4) intake..... if you like the stock airbox, keep it, but there's a reason why everyone gets those cone filters. the turbo inlet duct is pretty restrictive also.

5) diff. mount. i've broken so many of these i don't even bother replacing them---i just welded a girdle around mine. it's not a solid weld--which would lead to vibration, just a plate surrounding the rubber. it hasn't given me any trouble since i did this.

black_sunshine

Aside from porting the motor, port the wastegate on the stock turbo! The S4 wastegates are tiny, and once you uncork the exhaust, they'll tend to spike a lot, even with a separate boost controller. a band-aid fix for this is a pop-off valve (not a blow-off valve). Upgrade the BOV while you're at it; the stock one is good, but it never hurts to get a nice loud one.

As far as the injectors are concerned, it depends on what you're looking for. Also, keep in mind that you'll want to get "low-impedence" injectors, unless you want to bypass the resistor pack (passenger's side front, under the air box). The Bosch 1600cc/min top-feed injectors are around $250 a pair. They require some small modifications to the fuel rail (the holes have to made larger; might be more things that need to be done, but I've not heard of any). There are many places that sell injectors. Most diesel shops can get them and they also have the equipment to balance and/or blueprint them. I know that www.rx7.com sells these, but I'm certain there are other places as well. Just for refrence, the stock injectors should be 550cc tan-topped injectors.

The BEST "free" horsepower that can be had is from porting. Especially the intake manifold and obviously the engine. This way, it can make more power with less boost. If you want a really nice page all about porting, https://www.rx7club.com/showthread.p...hreadid=212537
is strangely informative; it's for an N/A, but the same theory applies to turbos. CUT CORNERS! Literally. Sharp corners on the plastic parts and what not create turbulance which mildly reduces horsepower.

I probably don't need to say anything, but if you're going to rebuild the engine, make sure to get new springs for the apex seals, side seals and corner seals. Make sure to get the 3rd gen. corner seal springs. They are way better than the stock "wire" type (atkins sells these for a pretty resonable price. Actually, their entire rebuild kits are reasonably priced; check ebay http://cgi6.ebay.com/ebaymotors/ws/e...sort=3&rows=50 ). . Viton Oil Control Rings are awesome (and they don't deteriorate when using ATF juice to un-flood the engine).

I know a lot of people who swear by K&N filters, and an equal number who swear by foam-element filters. I personally like the Ractive heat-shielded air filter; the heat shield can be attached to some dryer hose for a nice (albeit a little ghetto) CAI. Speaking of intakes, if you go with a separate fuel controller, you can get rid of that horrible power-robbing AFM (but you'll have to wire the internal fuel-pump switch somehow). Also, I don't know how pheasable it is, but I've heard that some people move the AFM to be after the turbo; I also heard it involves quite a bit of work.