Turboing 25de Neo: Tps & Tcu For 25det Pfc Problems? (help)

[putraged]

Disclaimer: i know some of u guys will say "sell the freaking N/A and get the GT-T", but the thing is i bought this car for pretty expensive price tag (from a dealer in melbs, which is gone bankrupt last year), and also 2 years with my 1st coupe car that brought me for a trip from QLD down to kangaroo island brings me lots of good memories back then.

im recently on the way of turbo-ing my 25DE neo (after giving up 25DET neo swaps: nb DET engine for sale). while im drawing the big picture of my plan, a question came into my mind. i hope u guys can give me any hint since i'm trying to do it by me and mates with some electrical & mechanical background. i will get the proper tuning by professionals.

how do i put my R34 Gt-t PFC on to my N/A R34 if the sensors aren't exactly the same? (refer to the picture below)

1. unlike DE neo's, the DET neo's got more sensors (throttle control unit, throttle motor sensor, throttle motor). IF i'm going to slap it straight away without these throttle units, will my PFC readings got messed up? or should i do it "properly" by putting DET intake assembly?

2. should i wire the turbo pressure sensor according to the diagram? (turbo pressure sensor pin 1 to throttle position sensor pin 1, pin 2 to ECU pin 47, etc)

3. on RB25DE the ECU pin 104 goes to Variable air intake control solenoid valve, meanwhile on RB25DET the ECU pin goes to turbo pressure control solenoid valve. can i leave it the way it is and not affecting the PFC readings?

4. my best guess for FPCM (fuel pressure control module) is to ignore it since my direct-feed walbro pump will be sufficient enough.

so far im waiting for my hardware package to come (brakes, turbs, dump, EBC, FMIC, injectors, etc) and after dealing with PFC problems & tuning, this winter's gonna be "fun"

i will be very delightful with any constructive comment.

thanks

For Reference Only:

[lachlanw]

answer to #1 is secret squirrel tweak . what you have to do when you put a gtt ecu in a manual stagea as they dont have traction controll either

#3 all that does is povide an earth from 4500 rpm to redline . you could wire in somthing with the same resistance as the solenoid

[Aggroman]

I have put a GT-T PFC in my rb25de neo. I didnt have a problem with number 4, I just swapped the fuel pump for a walbro (it plugged straight in to my stock cradle and plugs.) and fuel pressure is handled fine with no problems

The only problems I have are with the traction control but that will be solved with the secret squirrel technique.

With the Variable manifold valve or wateva u want to call it, I am looking into using the pin out for the turbo pressure as that operates the same as the variable intake and altering the voltage to trick the PFC or as a temporary stop gap you can set the solenoid to the always open position with a constant ground, which is what I have at the moment.

If you find a way to solve this please let me know..

You cannot use the DET intake assembly without changing your runners as they wont bolt up ( I tried this already)

Another thing to watch out for is that your VCT solenoid still operates properly As mine had to be disconnected for now because of 4V on the ground side of the circuit. I havnt checked it all out yet to see if thats a PFC problem from the conversion or if it just happened to fail at the same time.

If you would like to discuss ways to go around it please feel free to PM me

[666DAN]

#2 you can ditch the pressure sensor full stop (it's just overboost protection) but you need to run a signal to trick the ECU, easiest way it to take the 5v TPS feed, run it through 4 diodes then into the pressure sensor signal wire.

By doing this you drop about 2.4 volts accross the diodes (off the 5v signal) giving ~2.6v ie exactly what the ECU is looking for

Based on that logic you could also wire this same 5volt output to pin 51 (~3.4v so use 2 diodes) & 53 (~4.7v so only use 1 diode) and it would ignore the TCS system (probably what the 'secret squirrel mod is)

[R34 -_-]

I want to turb my car before the end of the year but the question i have is, is it really worth all the hassle and expense? just reading the threads about it makes it sound very confusing and problematic and if i were to get a work shop to do all the work it would probably send the bill sky high with all the fiddling they'd have to do

[putraged]

thanks for the constructive comments guys.

@lachlan:

secret squirrel tweak? u mean faking the ECU inputs?

so at 4500 RPM and above, pin# 104 should be ground with certain resistance? what about idle and up to 4500 rpm?

@Aggroman:

yeah, Walbro should be sufficient as long as i upgraded the injectors

to put the variable bla bla solenoid open, should i cut the pin-2 and tap it to ground instead to ECU# 104? (since pin-1 came from ignition). i hope 666dan can explain this as well.

i have the whole DET runner but im gonna sell the whole engine package instead of messing & bolting with DE runner.

i'll watch the VCT as well, thanks.

@66dan:

okay, the whole point for pin# 47,51,53 is to tap 5 volt and put diodes each before going to respective pins? where do i get this 5v feed? should i take ecu pin# 48?

thanks for sharing the secret squirrel tweaks, Dan.

@Brock:

you should ask someone who already turbo-ing their car in a workshop and compare it with DIY-ers. if you're willing to learn new mechanical & electrical skill, prolly DIY is worth-it unless u want to pay over a grand for the workshop. for me, doing it with my own hands makes me more confident with my own car.

so far i've put the whole idea into excel, please CMIIW.

Edited May 17, 2010 by putraged

[R34 -_-]

I'd love to do the work myself ( i could put the exhaust on lol) but its my daily driver and i need it to drive to work.

Let me know how your project goes

[666DAN]

Yep just use pin 48, it's the 5 volt reference supply for all 3 sensors anyway.