Jump to content
SAU Community

Recommended Posts

what car what mods what engine???

the mass airflow meter converts the amount of air drawn into the engine into voltage signal . The ECU needs to know int6ake air volume to calculate engine load, this is necessary to determine how much fuel to inject into the cylinder.

this means that when the AFM runs out of scope there is no more fuel injected into the cylinder than there would be at full throttle so when the air flow meter reads full load its supplying the max amount of fuel so if the AFM cant read anymore air coming in it can not suplly the fuel for it to ignight so you basically run out of puff

so what you will feel is nothing just wont make any more power

but if the car is unmoddified you will never reach this point

people if this is incorrect please let me know this is my understanding of the opperation

of the AFM

with the Q45 there is no way with those mods that you are maxing out your AFM get oyur car to a tuner and on the dyno and get your fuel and ignition checked and get them to test the AFM voltage and see if its reading correctly

yeah 5.0 volts is the max, or dead on. if its only a temporary max out its probably ok

but if its maxing out at like 3500 and stays at 5 volts the hole time then its a problem.

if its juts for quick second or two its no big drama. the ecu just wont see any more increase in airflow so more air is coming in than the airflow meter can measure

it doesnt feel like anything really. im maxing mine out, ive just got afm max warning turned off (flashes the engine light). im still on stock rb25 afm

well if you have datalogit why not do a 0 to redline run (on a private road of course) in 3rd or 4th and then look at the datalog report, from there you should be able to see what goes spastic past 5000

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Sounds like you've got an interesting adventure ahead here with local support if you have trouble! My guess is that, unboosted, you will be OK with a small upgrade like -9. What will happen is that once the stock ECU sees more airflow than it expects it will add a heap of fuel and pull a heap of timing to be safe because it can't understand how it could get that much air without there being an issue. You will see clouds of black smoke and it won't pull hard through the midrange and top end. So, overall it will be a bit frustrating but should be OK. If you are still nervous set the base timing back 2o through the CAS, but it will be even more sluggish everywhere. As said above through...this is not my guarantee your engine won't be blown into a million pieces, leaving you looking for very hard to find parts A better idea is get a computer with logging ASAP, wire in a wide band O2 sensor and a use remote tuner. I've done multiple cars this way and while it is not as good as a specific tune on a dyno they can get it 90% right. I'd suggest if you can afford an R33 GTR these days you can afford an ECU and tune. And if you can't afford that you sure won't be able to afford the rebuild if it goes bad in the meantime,.  
    • Yeah it would be nice if someone took the time to put that sort of information together, but there are a lot of variations in looms. I think you are making this way hard for yourself if you just want to get it running....sourcing an SR20 with the right wiring will be a billion times easier than matching the RB loom to an S15 chassis. If you do end up going this way, you just need to trace every wire in the loom with a multimeter, 95% of them will go to a location you can confirm at the ECU.....and then post it up for the next person who needs it  
    • Just top it up with water, and keep a general idea of how much you added. It is normal for water to be pushed into and pulled out of the reservoir through the cap, and it should not be more than half full or it will be likely to overflow when hot. Any decent mechanic can do a pressure test of the cooling system to confirm if you have a leak. Keep in mind if it is only leaking a little and when hot it may well evaporate before you see it hit the ground
    • I'd ask the shop what they used and use that. Mixing coolants is sometimes OK, sometimes not, and you have know the details of each coolant to know whether it's a good idea or not.
    • Is it alright to top up with just another green coolant?
×
×
  • Create New...