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Will A Standard R32 Gtr Computer Run Rb20 Afm

iwantagtr

By iwantagtr,
in Engines & Forced Induction

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Guilt-Toy Grand Master

Guilt-Toy

Posted
Posted

try it.. see what happens. all afm's do is supply a 0-5v signal to the ecu. sure the signal might not be what the ecu is expecting for the given air flow but how far out can it be?

im guessing it will start and run but how it good it will run?? - who knows :cheers:

winstonusmc Enthusiast

winstonusmc

Posted
Posted

The computer can be rescaled via changing the ROM chip on them. The ECU can be "chipped" by someone or even you if you want. I am running twin RB25 NEO E60 MAFs on my RB26 right now with a chipped R32 GTR ECU.

The reason why it seams that it is working now is that at low load, the engine is in closed loop fueling. The AFR is being calculated off of the O2 sensor, not the MAF. Of course once you try to take the RPM above 3000rpm, it will go very lean and could cause damage.

XRATED Veteran

XRATED

Posted
Posted (edited)

RB20AFM's will plug straight into a stock 32GTR harness (same plugs).... good for 400+rwkw worth of resolution. It will start on a stock computer but don't drive it before it's re-tuned.

J.

Edited by XRATED
iwantagtr Rising Star

iwantagtr

Posted
  • Author
Posted

Thanks to everyone who has replied. I have tried to start the car using the standard computer as well as using an apexi pfc (I bought pfc 2nd hand and apparently a tuner locked it) though the car does not want to start. I haven't started the car for about a year now as I have done a bit of work such as installing:

garret 2860r-5

custom intake pipe work

rb20 afm

fuel surge tank using a bosch 040 fuel pump

sard 800 cc injectors

larger fuel rail

placed the battery in the boot

I was hoping the car wouldn't start because the afm's weren't talking to the computer but obviously i was wrong. By the sounds of it I have done something I shouldn't have or I haven't pluged something in.

Cheers

JonnoHR31 Grand Master

JonnoHR31

Posted
Posted

make sure your getting fuel and spark. altho you'll have a real hard time making it drive with the stock ecu, try and find someone here in your area with datalogit so they can setup the pfc for you and make it driveable

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

It's going to start in limp mode anyway due to the AFM's.

I struggle to get my car started in limp mode (same as unplugging the AFM), so im not surprised you are having the same issues as well.

Add to the fact you are also running 800cc injectors & fuel rail - honestly mate, you are pushing shit up a hill.

iwantagtr Rising Star

iwantagtr

Posted
  • Author
Posted
It's going to start in limp mode anyway due to the AFM's.

I struggle to get my car started in limp mode (same as unplugging the AFM), so im not surprised you are having the same issues as well.

Add to the fact you are also running 800cc injectors & fuel rail - honestly mate, you are pushing shit up a hill.

This may sound stupid but the only way I will be able to start this car is by taking it to someone who can get into my computer ie.tuner/dyno

winstonusmc Enthusiast

winstonusmc

Posted
Posted

The funny thing is with the correct injector MAF combination, the fuel could correct itself enough to actually drive a little bit. Now the timing throughout the MAP will be totally wrong, the fuel AFRs shouldnt be too off to not run at all. Now being that the RB20 MAFs are about 150% flow capacity of the stock RB26 MAFs, then the 800CC injectors are 56% which is close enough to 66% to get the fueling close enough to run. Now remember that the timing curve will be way off.

I remember back in the day before PowerFCs and ROM tuning was readily available, guys used to drop a Z32 MAF and 720cc injectors in an SR with the stock ECU and actually drive it around like that because the two would sort of compinsate for each other. But the thing still ran like ass because the timing curve was off.

All this aside, avoid driving this beast before you get that PowerFC unlocked.

Lukas 33 Proficient

Lukas 33

Posted
Posted

Seriously how far is your tuner? My car wouldnt go so I had to tow it 350km to get to my tuner. What a fcuking stupid journey. If it is like 20km or so then just get the tow truck and save yourself the headache.

iwantagtr Rising Star

iwantagtr

Posted
  • Author
Posted
Seriously how far is your tuner? My car wouldnt go so I had to tow it 350km to get to my tuner. What a fcuking stupid journey. If it is like 20km or so then just get the tow truck and save yourself the headache.

I never had any intention of driving the car around I just wanted to start and idle it so I could see if I had any leakes.

A big thanks to everyone I am learning heaps

aphid Proficient

aphid

Posted
Posted

Just check the basics as has already been mentioned.

Ignition - Throw a timing light on the car and check the timing while you crank. If it's not around +15deg then your timing is out, if it's not flashing at all then check your ignition fuse in the boot & everything in between.

Fuel - If the car has ignition and you can't smell unburnt fuel out the exhaust, pull the CAS off and spin it with the ignition turned on, you should be able to hear the injectors fire. If you can hear them firing and still nothing then pull the high pressure fuel hose off and put it into a bucket and again flick the key to on. Fuel should spit out into the bucket.

If you have all of these things, the car should start. I would use the power fc over the stock ecu any day to get it running with. Scale the injectors correctly and set the afms to RB25 (RB20 & 25 are the same thing) and try and start then.. Just continue to mess around with the tune till you get somewhere :)

Also, if it's been a year you might want to change your fuel, it tends to absorb water and break down over time.

My 2cents :(

JonnoHR31 Grand Master

JonnoHR31

Posted
Posted
I would use the power fc over the stock ecu any day to get it running with. Scale the injectors correctly and set the afms to RB25 (RB20 & 25 are the same thing) and try and start then.. Just continue to mess around with the tune till you get somewhere :D

thats the problem, he cant because his power fc is locked, meaning you cant change any of these settings with the hand controller, some tuners do it to stop people who dont know what they're doing playing with it. like i said you need to find someone with datalogit who can help you out if its locked, takes 5 mins

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