Previous thread i made stated how after putting my FD project together and getting it running made me find out that the stock ecu would go into limp mode with a t78 turbo kit and full exhaust etc.

Ordered a PFC with controller. PFC still has the base/map. Few questions are does the pfc show omp values? After installing the pfc with base map what psi should i set boost at to start with? And last question what would be the max psi i could safely run with a t78 on the stock fuel system?

 

Probably 8 to 10 psi on the stock fuel system. You better hope you don't have any boost creep.
The base map is not setup for a single turbo BTW, you better get the car tuned...

 

Start low. Is it a fresh engine? I wouldnt boost high and its going to run like *** on a base map. Are you running stock injectors? No fpr? Gonna have a bad time.

 

It's not going to run great on the base map. You also need to disable Seq. Turbo Control from the Etc. menu.

Changing from stock sequential twins to a single turbo is a big change on the car. The factory computer can't handle it because it's not programmed to. It doesn't know what's been added and taken away, it only knows to look for certain things and freak out if they're not there.

The PFC is a great little box and allows you to program the crap out of it and control a single turbo.

I suggest you ask a few questions on the PFC section of this board.

-Geoff

 

The is a PFC yahoo group that you can pay to join. Its a great group with lots of knowledge. I suggest you consider joing.

 

I will look for the pfc section on the board and search there. Thanks for the responses. I do still have the stock fuel system with no fpr. As i said in my last thread i bought the car in pieces as a project but figured with the engine papers and the receipt for the turbo it would be worth a shot to try and put together and get running.

Can the PFC monitor OMP values?????

As for boost creep/spike i just recently purchased a good condition 50mm greddy WG so at least i have that on my side. I was planning on trying to run 10psi. I do understand that might be around 100% injector duty.

So to start i will disable the seq. turbo in the etc. section. and from there search and learn in PFC section.

 

Yes. Go to the Sensor screen. It's there under MOP. If the OMP malfunctions it will be a shaded value and probably at default voltage, which IIRC is 4.99v. You won't go into limp as you would with the stock ECU, so you should check things on a regular basis. But otherwise it should give you real-time values in voltage.

 

Exactly what i needed to know. PFC should be here in a few days. Cant wait. If the mop is giving 1-2 v readings at idle and inscrease steadily per rpms then that will be awesome. if it gives me a set 5v reading like your saying then ill just start going 1 oz per gallon in the tank. Ill set the boost to 8-9 psi and disable the seq. turbo option and start from there.

 

for everything that is holy...... UPGRADE YOUR FUEL SYSTEM, and DO NOT GO INTO BOOST. otherwise.... goodbye motor

Even at 8-10psi, the T78 far exceeds the maximum airflow numbers of the stock twins at 15-16psi.

Even with a PFC you can still pop your motor.

So please, do not be in a hurry to go fast

 

I don't understand.....I would think that 8 to 10 psi at the manifold (where the boost sensor reads it) is the same no matter what turbo...or how many turbos you have producing it ?

 

So a 30lb propane tank at 10psi has the same amount of propane in it as a 55 gallon drum with 10psi of propane in it?

 

I'm not seeing your analogy. A nozzle on either tank limited by a regulator (BC) to 10 psi doesn't care how big the tank is. It's still only going to produce 10 psi at the nozzle. And it's the psi at the nozzle/manifold that we care about isn't it? Because that's what determines fuel needs.

 

typical fd will make close to 400 rwhp on a t78 at 10psi

It makes about 300 on a similar setup car with twins at 10psi

Maybe that will help you compute how crazy running a t78 on a stock map is.

Remove the t78 or spend 5k to set the car up properly to use it.

 

Well, I don't understand it, but take you guy's word for it. Never have to worry about it personally, and the OP has been warned, so there's no sense going farther off-topic.

 

Think of it like this.

One blows hotter air and I'm sure you can guess which one A t78 has a big manifold, BIG turbo, BIG compressor etc.... so it doesn't compress the air or heat it up nearly as much as the twins. Couple that with a high flowing exhaust a good VMIC and you can make serious power at just 10 psi.

Colder air is denser or thicker so it can produce A LOT more power but it also need lots of fuel so IMO an engine with t78 bolted to it making 10 psi on a twin turbo base map will last for one 3rd gear pull

 

Take it from me.. I went from stock twins 10 psi to a GT35R 10 psi and blew the motor the same day i finished the car on my first highway cruise!! Then after much research and asking tons of question i then understood that is not the same...


To the OP i know you are dieing to get your car running but take your time, hook up with some local rotary heads that can help you out or take it directly do your tuner...

 

Wow, very interesting and good to know. So it has to do with volume type of thing i take it. For example fuel pumps, a large pump at 10 psi produces a lot more volume than a small pump at 10 psi. Same with the turbo housing, 10 psi of the amount of air coming out of a t78 is a lot more than small stock turbos.

Fritz - t78 on a street port motor will make 400 @ 10 psi ??????? Thats nuts, if so i should def look into a fuel system. Maybe 550 pri. 1600 sec. an FPR and a supra pump. How does that sound to start?

 

Sorry for the double post i just wanted to throw in there, cant i increase injector duty with the PFC a good bit and retard timing some to maybe get the car running to at least 8 psi? I do understand the map will have to be different for a smooth powerband but i would think the stock fuel system near max could handle the t78 under 10 psi. Of course please correct me if im wrong. Which i very well could be. This is fun though. The last time i was doing this was with 944 turbos using my old Dell and some cheap Moates standalone crap.

 

Yes you can adjust all those things with the pfc but for the love of god DON'T. Tuning a rotary is very different from all other motors with an extremely low tolerance for mistakes. The fuel setup you mentioned would be fine but don't run the stock injectors/pump at 100%, its a terrible idea on the twins let alone a t-78.

 

Just FYI... The fuel pump is one thing, your regulator and injectors are completely independent. Therefore just slapping a larger fuel pump in the car doesn't automatically add more fuel for combustion.

 

No no i wasnt planning on adding just a pump to give my car more fuel i was giving an example on how pressure and volume are two different things.

93 rx7 is your pic taken in great falls or clifton?

I think ill get the PFC in and make sure the the cars limp mode prob is gone. I wont do any pulls and ill start shopping to put together a fuel system. Cant imagine pulling the tiny intake off and replacing the injectors is that tuff. Should probably get the banzai block off plates to get rid of the aws and stuff under there. Do i need to research the injectors and find out what impedance i need? Do some injectors need resistors?