Hi guys, I've just spent several hours shearching a thread with the full specifications of the stock twinturbos (Hitachi HT12) , like inducer, exducer, trim and a/r from the primary and secondary turbos... I'm considering replacing the stock ones for some more powerfull ones... does anyone knows anything about CXRacing(they have many turbos with different setups)? Should I stay sequential or turn to non-sequential (you must have in mind that I'm from Portugal and here theresn't a single shop to tune a rotary engine, so the changes I have to make can't be in the ECU)... I'm going to rebuild my engine myself with a rebuild master kit from Atkins Rotary and I want it to be stronger (I'm tired of some guys with Audi's S3 messing around). If I ever finish this project, I can realy say that I've build it, not bought it(i've bought my REX in pieces, teared apart for 12 years).
Any advice from you gurus is always better and very welcome... THANKS


STILL VERY PROUD OF MY REX!!!

 

ok, any thought of upgrading the sequential twins, is going to require more fuel if you're going to run more boost. with that being said, you're going to need a stand alone ECU in order to tweak the fuel settings for higher boost. there is quite a bunch of useful information on this forum so you can learn how to tune your car safely without blowing it up. The guys on here will be able to provide you with a base map to get the car running safely based upon your mods and you can tweak it from there to get more efficient use of the fuel.

if you want to give those Audi fellas a run for their money, you're going to have to run higher boost.

There are honestly very few options if you want to retain the twins, weather it be in sequential format or not. The only two *real* options that I would consider are the +99 twins or the BNR stage 3 twins.

the +99 twins are cheaper than the BNRs but can/will not run nearly the same boost levels and stay running for long at higher boost levels. they are quite an upgrade over the 93 twins but not as quite and upgrade as the BRNs.

the BNR Stage 3 twins will allow you to run up to 21psi (with supporting mods, ie, fuel) and will do it efficiently. BNR however, will require you're core to work with as they will replace everything, including the center housing rotating assemblies and make them generally stronger overall to handle their advertised boost levels. They are also expensive, ~$2100 direct from BNR. And they take a while to get. It took them around 2 months for them to finish mine.

Weather to go sequential or non sequential is honestly up to you. It's a give and take at that point. Sequential gives you more low end torque, which is what the system was designed to do. NS gets rid of all those solenoids that control the sequential system so you'll build boost more reliably, albeit, you will hit full boost later; depending on how much boost you want to run.

I will always prefer a well running sequential system over a NS system any day, but that's just me.

Other than that, your other option is to go single......which is really easy now a days.

 

Hi Rx7 tuga! You and I are in the same boat, in my country there is no one that I would trust to tune my FD. I'm not an expert, but I'm sorry to say that even with minor modifications its highly recommended you get a stand alone ECU like the Power FC and get a really good tune, especially if you want more power...

You say that the changes you make cant be in the ECU, then if I was you I would leave the car completely stock...the stock ECU is very limited. It would be a waste to spend money on a rebuild kit and spend the time and effort rebuilding your engine just to blow your engine because your stock ECU could not run your modified engine properly...

 

Hi guys... I apologive for all the time passed since I've posted the thread and didn't said anything, but I'm having some other problems with my RX7... is it possible to get different readings from the TPS, like: ignition key on=0.95; engine running=0.80; cooling fans working=0.50== mixture lean at this point. I can't figure what's wrong, maybe a bad harness? The oil pressure gauge sometimes drops to zero... thanks for your time and advices...

 

Several of the critical engine sensors, including the TPS, are supplied a regulated +5v reference voltage (and ground) that originate at the ECU. The +5v should be stable under all conditions--if it is not, then refer to the FSM and investigate everything associated with that buss until a clear cause is found.

I suggest inspecting & paying close attention to all of the [connector] pins and wire crimp connections as problems with corrosion are known to occur. And be sure to carefully check all of the wires/crimps/pins at the ECU connectors for evidence of corrosion as well; I know it's a pain; however, you may want to verify the presence of the correct voltages at the ECU.

Over time, moisture and contaminants can degrade connections and residual process chemicals in the wire and insulation can leach out and cause electrolysis to occur at the connections, eventually resulting in a failure.

Evidence of corrosion may include the presence of bluish-green or white color powdery deposits near the pins and/or wire crimps.