I know this has been discussed before, but I can't find anything with a search.

If someone can point me to a past discussion to answer my questions I would really appreciate it.

If I want to convert my turbos to '99 + turbos, the set with 280hp rating, what is involved besides bolting them on?

e.g. wil I need an ECU conversion?; vacuum modifications?; updated cooling system?; etc.

I would really appreciate some help.

Thanks,

C

Also: Does anyone know how to tell the difference between a 265 hp rated set and a 280hp rated set?

 

The 99s and the stockers look the same.

 

The 99's have the plastic lining inside by the compressors, the 255hp & 265 hp ones do not.

I believe the compressor fins might be slightly different on the 265 vs. the 255 versions, but you would probably need them side-by-side to tell the difference...


Also, NO. You do not need anything else to run with those. No ecu, cooling, etc.

 

Thanks guys...

r0t0r-rooter,

So I should be running the 280hp rating as soon as they're bolted on and connected?

-C

 

No, the addition HP for the later versions of the FD were also from running a higher stock boost level (along with a newer ECU tuned for it).

Just running stock boost levels with the '99 spec turbos probably will not add any extra HP, but you'll have quicker turbo response.

 

Ok,

So with a boost controller and engine management system (tuned for the new turbos)...I should be able to achieve the extra horsepower?

-C

 

They turned it up to about 12 PSI. If you put in a Power FC and use the base map you should have the rated HP. AFAIK the PFC still comes with a 12 PSI base map.

 

Thanks David Beale,

I'm not really clear on all the terminology, so for a little clarification:

I should get a Power Fuel Controller (which would facilitate the higher boost alone?) and use my stock ECU.

-C

 

Apexi Power FC fuel controller is a stand alone fuel system...
it bolts up to your stock ECU

 

Thanks Rhode Dog,

I'm still not clear on wether or not the fuel controller is going to give me the higher boost in the new turbos.

-C

 

It will allow you to have maps programed to allow for fuel at higher boosts.

 

Ok...

So it seems that I will still need a boost controller to go with the FC...keeping in mind these are '99+ 280hp turbos.

-C

I really appreciate everyone's input.

 

Type in "jspec twins", and here is the thread you're looking for: https://www.rx7club.com/showthread.p...ht=jspec+twins

Quote:

If I want to convert my turbos to '99 + turbos, the set with 280hp rating, what is involved besides bolting them on? e.g. wil I need an ECU conversion?; vacuum modifications?; updated cooling system?; etc.

If you're not adding any other power modifications to your motor, then it's a simple swap and bolt-on procedure. Assuming you change nothing else, you will feel quicker spool-up time--primary boost @ 2300 to 2500 rpm. The US specs primary boost is between 2800 to 3000 rpm. The J-spec 99s' quicker spool-up time comes from its redesigned compressor wheels (smaller diameter) and abraided housing seals (which have zero tolerance). This allows for more efficient boost production (less heat generation too).

 

No the Apexi Power FC (fuel computer) REPLACES your stock ECU. It's not a piggy-back system like the PFS Purple. The Apexi unit is fully programmable using the FC Datalogit software and wideband lambda oxygen sensor. The base maps loaded on the Power FCs are stop-gap maps, to get you by until you can have a proper dyno-tune performed by an authorized Power FC/Excel tuner.

 

Right. You can adjust the air-fuel ratios, ignition, injectors duties, etc. with a Power FC. It's completely user adjustable, where as the stock ECU is not. There are "chips" you can swap out on the stock ECU (called reprogramming your stock ECU) based on your current mods, but this has become obsolete, with the advent of fully programmable unit such as the Apexi Power FC.

 

No, the Power FC controls boost pressure just as the stock ECU does--through the duty cycling of the precontrol and wastegate actuators (via control solenoids). With the Power FC, you adjust the precontrol (Primary) and wastegate (Secondary), by setting a target boost (kg/cm^2) and adjusting the base duty cycle for each (Primary and Secondary) actuator. There is some tuning involved here, since the Power FC unit needs time to learn your driving style.

Amazingly the unit does a good job controlling boost--IME, within +/- 0.05 to 0.07 kg/cm^2 (+/- 0.7 to 1 psi). The ambient temps will determine how close the Power FC comes to your target boost levels. Warmer weather will result in slightly lower boost (so you adjust the duty cycles up); cooler weather will result slightly higher boost (so you adjust the duty cycles down). The higher base duty cycle, the higher the boost level. The lower the base duty cycle, the lower the boost. You must adjust both the target and the base duty cycles for proper boost control (duty cycle is %).

There are many FD3S onwers on the board who install stand alone boost controllers, such as the GReddy ProFec B (which is the best one to use for sequential twins). The ProFec B bypasses the stock precontrol and wastegate control solenoids.

I've read the stand alone boost controllers do a better job of controlling boost (meaning your actual boost is much closer to your intended target boost)--particularly for FD3S owners who switch to a large single turbo; they find the Power FC's boost control to be inadequate (the Power FC makes use of the stock MAP sensor). Since many single turbo owners run boost levels that exceed the stock MAP sensor, they usually add higher boost capacity MAP sensors, and stand alone controllers to deal with 1.4 kg/cm^2 (20 psi) boost levels.

Note on boost pressure units: 1 kg/cm^2 = 14.22 psi; 1 Bar = 14.5 psi; 1 Bar and 1 kg/cm^2 are NOT equivalent units. Note that the Power FC's boost pressure units are kg/cm^2).

 

As a general rule, if you increase intake air volume, increase exhaust flow, and cool the intake air charge more efficiently--boost pressure will rise, and air-fuel ratios will lean out. This is good for hp production--up to about 11 AFR (air-fuel-ratio).

Greater than 11s, and you run too lean, the motor detonates, and you pop an apex seal. This is why you need a stand-alone ECU replacement to inject more fuel in the combustion chamber to maintain your pre-set AFR (which is what is user adjustable on the Power FC's 20 cell x 20 cell "Power Excel" map grid, as seen on the FC Data Logit software).

If you upgrade the air intake system, install a larger intercooler, free up the exhaust tract (by removing the cats, and installing a catback exhaust) your turbos will make boost very quickly, and can make higher peak boost levels than before. Without adequate fuel enrichment, your motor will make big power just before it destroys itself!

Upgrading the air intake, intercooler, and exhaust, at the same time, you've broken the "3-mod rule"; requiring an upgraded ECU (M2 ECU upgrade) or stand alone ECU replacement (such as the Apexi Power FC).

 

From what I have read and all information I have gathered, the 280Hp will not be achieved without adding the Efini Y-Pipe. All discussions from Mazda that I have researched indicated a 10Hp increase with the Efini pipe versus the rubber coupled two piece pipe. Some people have stated this is not true, but I do remember reading about it somewhere and it was not just a forum opinion. The abradable compressors are 80% VE compared to 75% VE on the 255-265Hp turbos.

This is what translates into the quicker response and better Hp ratings.

Tim

 

VE = Volumetric Efficiency?

 

Yep...

 

Way to come to the rescue, Manny

 

Just making sure the info on the board is accurate, Cap

 

 

 

how much are the j-spec twins? is it worth it for 30 or so hp, and the quicker spool time?
are bnr's in the same price range?