NITROUS OXIDE ( nos / n2o ) advice forum

hey all a little update on my car:
now with injectors from the 90hp and nozzels from a 140hp 2.0 diesel in them.
Larger VGT turbo charger running close to 1,5bars of boost, larger downpipe no cat.. 2"

I was maxing out my MAF so they said i should get a larger housing for the MAF so it would be cheated into seeing lower airflow!

i did this and the diameter increased by 1cm.. now the car is SLOWWWW full throtle with no load will take several sec. to reatch 3000rpm .. when the plug is removed from the MAF it is ALOT better..! have tryed with a semi faulty 1,9JTD 110hp maf (the one that orginaly had the housing i fitted) and that did the same thing..!

any thoughts!

(had the turbo sucking through a 51mm pipe.. and a small dirty filter = sounded like a diesel trucker with the turbo flutter sound at throtle liftoff NICE..! but not so good for the turbo.

now changed to a piper cross filter rated at 290hp and increased the size of the turbo inlet pipe to 63mm and a larger MAF.. now it runs mutch less smoke from the exhaust and does not have that truck sound.. :-( but atleast it will not hurt my turbo!

Sounds like it is a faulty maf

Although you have a smaller original maf does this work better?

Whose maf is it (Manufacturer) if its Bosch (very likely) then any scrap yard will probably have what you are looking for!

the car was running okey when in the orginal housing.. now about 1cm larger!
therefore it sees less air.. i think ... havnt changed anything els

I think that ideally - The MAF should see the 'correct' amount of air - what is actually going through. The bigger maf should just remove a restriction.

If it sees less air than is going in then the ECU 'should' cut back diesel to reduce emissions even with a remap. Less air means VERY sooty engine and less power as there is not enough air so if the MAF sees less then the ECU is actually doing the right thing.

I think the bigger maf to give better flow and the sensor needs to be the 'right' one for the housing so it sees all the air going in. The ECU should then sort this all out.

I'm no expert on this stuff. But are you saying that you fitted a maf sensor from the smaller housing into a bigger housing?

The same amount of air will flow through the big housing, but it will be at a lower velocity. If the sensor is calibrated for X amount of air velocity through the small housing to calculate air volume and you have fitted the same sensor in a larger bore housing the sensor will think less air is going in due to the reduction in velocity.

Probably all total crap. But its the way i see it should work

I assume that these sensors are calibrated to match a particular size housing??

I know didly squat about this stuff BTW

Just my thoughts

Yes - just like that pel!
You said it so much betterer than I

yes it is a bosch sensor.

it doesent work well with the marea sensor in its own housing either.. still messuring to little flow .. the resistance in the wire must be different..

the reson i upgraded was that the ecu reports a:
air quantity sensor signal to high.. it has reatched its max output on the sensor.. so a bigger hole around it would give it more air without it maxing out the sensor.. but now its to little to drive the car, only if i unplug the sensor does it drive "near normal".

turbo+intercooler+large injectors+boost+clutch+low restriction exhaust+no cat
what does that do on this engine? = you can drive it from 1500rpm with a ok pull and shift at 2200rpm... or you can pull hard from around 1800rpm to over 5000rpm with a curve that feels like its raising all the way past 5000rpm and expect around 4-5sek off 0-100km/h
acc in 5gear is like 3gear in a standard. when the thing works its alot of fun!

Sounds like you need your engine tuner to sort the map on the ECU - it should be possible for them to reset this so it works all the time!

Problem is - its moneY!

I found the coolest thing!!

http://autospeed.com.au/A_2418/cms/article.html



Digital Fuel Adjuster

> Modify air/fuel ratios
> Allow air-flow meter or injector swaps
> Change closed-loop running characteristics
> Overcome Boost cuts

Ref: Performance Electronics for Cars - Silicon Chip Magazine Publications.

This unit is a huge revolution in DIY automotive performance. It gives you the power to completely tune the air/fuel ratio throughout the entire load range, at 128 load points, providing incredible mapping resolution and brilliant drivability. It uses the Handheld Digital Controller - KC-5386, so there is no need for a laptop, and it supports both static and real-time mapping. It can be used on 0-5V and 0-12V signals, so it is compatible with all voltage output airflow meters and MAP sensors. It can also be set to work with 0-1V signals, allowing modification of EGO sensor signals. This unit has been extensively tested on a wide range of cars including Subaru Impreza WRX and STi, Nissan 200SX, BMW 735i, Lexus LS400, and Nissan Maxima. Kit supplied with a quality solder masked PCB with overlay, machined case with Processed panels, programmed micro and all electronic components.

Kit requires the Handheld Digital Controller - KC5386 and connecting cable WC-7502 (25 pin RS 232 extension cable with all pins connected).


"It is absolutely no exaggeration to say that the release of the Digital Fuel Adjuster is going to cause a revolution in the budget engine management modification." Julian Edgar, Silicon Chip Magazine.

Isn't that just the same as the apexi safc kit but you have all the controls on the unit instead of having to use a seperate controller

Surely if the sensor sees less air it will inject less fuel I thought diesels Could make use of more fuel

well the point is that the sensor sees to little air and limmit the diesel.. and this thing can make it think its getting more air!

What about keeping your large bore maf and fitting one of those diesel tuning boxes that way you keep the higher airflow and tweak the fueling with the tuning box

im buying one of thoes apexi safc II.

easyer.. than getting one of above..