Will i need a pfc for my mods?
 

Hi, building on my FD and currently got 3" downpipe back exaust with a racecat and going to get a re amemiya smic and do the cheap intake mod. Currently there is a knightsports 300hk box in the car but I am a bit worried that I will need a pfc and boost controller to not blow the engine. Should I worry or will the knightsports box be enough? Going to buy a pfc later but no money for it at the moment.

A side question how many hp can I get from the stock twins with the re amemiya smic? Want it reliable but still 350-400whp..

Need a PFC - Yes

400whp on stock twins... never. :)

All you might need is a boost controller on those mods. You don't need a PFC right now. But a reliable 350-400 hp on the cheap isn't possible. If a PFC is out of your budget, then so are those goals. Stop "building" to a number.

Well 350whp seems more realistic with stock twins. Pfc is not really out of my budget its just that I have bought a load of parts for the car so the pfc will have to wait till next month simpel as that. Not looking for a on the cheap build (hence the re amemiya smic) just got a lot of stuff coming in so need to buy parts step by step.

Need to get the car resprayed, rebuild the turbos (blue smoke at high rpm :( ), change out the vacuum system so the money disappears fast.

wait til you go single :P its like magic watching the money disappear

Cant go singel ;( Swedish laws forbids you to do any power mods with your car. That's why I got a smic and keep the twins. Won't be that obvius unlike a huge sigel turbo and v mount ic :p

Need fuel mods, cooling mods, pfc, and significantly raised boost for that hp level. And even if you're able to rebuild the turbos successfully their lifespan will be shortened.

There is a big aftermarket rad that the old owner put on so will check if its big enough when I take the front off. Know that the things I mentioned is not enough for 350whp but its a start and my end goal is 350 with tt then I might get another engine so I can run single turbo w/ streetport then use the original engine for mot.

if you want 350 with the twins then you will need ECU, fuel pump, injectors, fuel rail for the bigger injectors, boost controller, intercooler, and pref some form of secondary injection (water/meth etc).
350rwhp will take a fair amount of boost with the stock twins hence the suggestion for secondary injection.

not to be a downer, but IMO, if you havent yet pulled the trigger on the re amemiya intercooler then you should look at something else. Its just an intercooler, IMO not worth the huge price premium that the brand commands.
I know you dont want to do a "cheap" build, so that money should be spent on nice parts...like ID injectors, FFE / CJ fuel rails, quality fuel pump...and a modern ECU (i.e not the power FC, it does the job but its old tech nowadays)
in reality that intercooler isnt going to do anything for you that one 1/4 of the price cant also do. If you just want it for the bling factor, then by all means, proceed. Not the best use of limited resources though :)

Thanks for the advice :) I am getting the ic cheap if you compare to what they sell for here so can just sell it if I need bigger and in need of a smic for now so I wont have any issues with the MOT.

I really like the pfc because its PNP but maybe a modern ECU is not that much hassle to install. There is some nice ECUs with really cool and useful features that the PFC dont offer so I am kinda temped. How much work would it be to install a more modern ECU? I just dont feel like redoing the wiring.

There are now several "plug n play" modern ECU's around now.
I personally have link G4+ plug in ECU.
Im pretty sure adaptronic and a few others also offer PnP options for the FD.

The most important thing is to get an ECU that whoever will tune your car is comfortable with.
Link ecu's for example are made down here in NZ, so there's lots of support for them locally and lots of people to tune them.

First priority is to get something that your tuner can actually tune and is comfortable with.
Once you know what ECUs they are comfortable with, then pick whichever ticks your boxes from those options :)

Also be careful of running higher than 12psi boost on the stock twins- I ran 14psi on a JDM FD with the stock twins, and after a short period of time, the turbine shafts twisted off and the turbo compressor wheels fell off inside the compressor housings, destroying the turbos.

The stock turbo shafts are something less than 1/4" in diameter (can't remember exactly) in one place, and they shear easily at high boost.

Other thing is, the compressor design loses a lot of efficiency after about 11 or 12psi, and just begins to 'chop' the air instead of compressing it, superheating the intake air, etc.

That's why typically if people plan on more than 12psi, they ditch the stock twins for a set of upgraded twins (BNR, etc) or go single turbo.

Definitely more boost with stock twins will require a PFC and hope the twins hang together.

350 hp on twins is not reliable. That will take 15-16 psi and they are just too small and generate too much heat to last at that level. The stock twins are also not really rebuildable. The housings get distorted from heat so the new parts installed during your typical turbo rebuild always fail prematurely. You have a few options:

1. Find a known good used set of twins.

2. Buy a set of new 93-95 twins.

3. Get a set of 99 twins.

4. Step up to BNR twins.

The 93-95 twins won't last long past 12-13psi, and the 99's (which are technically smaller but more efficient) seem to like even less boost. Either of these can yield 320-330 hp max before reliability goes down.

We've made over 420 wheel hp with BNR stage 3 turbos. It would take a VERY keen eye to distinguish betweem any of these turbos with them installed on the car.

This is what I'd do:

Power FC
BNR stage 3 turbos
Downpipe
High flow catalytic converter (Bonez or RX-7 Store)
Catback
Mod the stock intake (cheap bastard or similar)
Greddy, Blitz, or other stock mount intercooler
HKS twin power ignition
Full Function Engineering FD step up kit fuel system with ID 2000s
Supra twin turbo or Walbro 400 fuel pump


This will easily yield a reliable 360-380 hp on 93 octane pump gas and have the potential to make more on race gas or with meth injection providing you have a solid motor and tune.

I can get you any of these parts.

Very important: don't boost past 10 psi unless you have an aftermarket ecu that is providing enough fuel.

Your first mod should be a boost controller. As you add basic flow mods your car will inherently have an elevated boost response. You will need the controller to bring the boost back down to a safe level.

Curious question to all of those more knowledgeable than me, but aren't the BNR's a pain in the ass due to poor build quality, lots of oil leaking, etc? If you are sticking with twins isn't it best to just use what you have or buy another used set?

Or you could shell out buckets for some new Hitachi HT12-3KAI's:

http://www.fdrx7.com/forum/attachmen...3&d=1374149521

http://www.ricshawracing.com.au/wp-c...urbo-kit-2.jpg

http://www.ricshawracing.com.au/wp-c...urbo-kit-3.jpg

Attachment 753073


280ps HT12 turbos

Attachment 753074




HT12-3KAI

Attachment 753075

http://www.fdrx7.com/forum/attachmen...6&d=1374306767

Apparently they can handle much more boost as they are made with stronger bearings, stronger shafts, have a larger wastegate and adjustable actuators.

I wouldn't spend the money on them as they are something like $3,000 equivalent but for those that want the best twins maybe these are it?

I believe the old original BNR turbos used dynamic oil seals on the compressor side which are finicky with oil sump back pressure and leaking (my experience is with BNR FC single).

If the drainage is poor or sump pressure is high enough even the rear oil seal will leak into the exhaust.
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I believe the new BNRs use standard carbon seal GT28 complete cartridges and BNR special cast compressor covers.

There should be no oil leak problems with these, but people do have a way of taking parts off cars and putting them on in ways they don't work.

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The biggest contributor to compressor side oil leaks on my FD with stock turbos has been when I had a boost leak and overspeed the compressor. Fixed the boost leak and oil leak stopped.

This has got to go down as a classic:

Unfortunate, but true--if not understated.


Humor aside, a properly installed set of the late BNR turbos should be fine. I agree with Blue TII's comments and would just add that anything you do to improve the FD's [woefully inadequate] crankcase ventilation system will likely help mitigate turbo oil sealing issues.

Och thats interesting! My boost is a bit low (most likely a leak) and the last time I drove the car I got a big amount of blue smoke when pulling on the highway. That might be what's happening on my car to. Will check the turbos to be safe when changing all vacuum hoses. Also got a efini Y pipe and new smic so will make sure the old pipes did not leak