tuning box

[geoffdown]

Nope, it piggy backs on the ecu. I think it tells the ecu the air temp is very cold and so ups the fuel to match, therefore making more oomph:naughty

so wheres the ecu then is it behind the glove box and how hard is it to fit the tunit box then

 

[makeitfit]

Mine is behind the center console but no idea where it is on yours:nenau
It seems nissan had a jolly time playing hide the ecu :lol

 

[Paul]

I think it tells the ecu the air temp is very cold and so ups the fuel to match, therefore making more oomph:naughty

If thats all it doe's, willn't it knock the co's and that up on the mot? :nenau

 

[Paul]

Makeitfit, so is this the same sort of thing..

http://cgi.ebay.co.uk/TUNING-CHIP-F...arts_Vehicles_CarParts_SM&hash=item3a630a3987

 

[makeitfit]

If thats all it doe's, willn't it knock the co's and that up on the mot? :nenau

Not had an issue on mine with MOT.:thumbs
PM Timbo, he knows considerably more than I :augie

 

[Paul]

Not had an issue on mine with MOT.:thumbs
PM Timbo, he knows considerably more than I :augie

Ta, could be usefull for towing the tin tent. :naughty

 

[makeitfit]

A seriously good bit of kit. it's like having an extra gear
No need to drop a gear to overtake, or just cruise at lower revs:thumbs
I prefer the "turn it up to 11" mode myself :naughty

 

[TONUP]

Am I correct in understanding that the MAF tells the ECU what the air temerature and density is?

Is it also correct that it does this via a piece of thin wire, which is heated?

Wouldn't it be simple... if you hard the nerve/money to increase or decrease resistance in this wire to 'fool' the ECU into increasing fuel delivery etc?

Or am I looking at this too simplisticly?

Alan

 

[zippy656]

Am I correct in understanding that the MAF tells the ECU what the air temerature and density is?

Is it also correct that it does this via a piece of thin wire, which is heated?

Wouldn't it be simple... if you hard the nerve/money to increase or decrease resistance in this wire to 'fool' the ECU into increasing fuel delivery etc?

Or am I looking at this too simplisticly?

Alan

http://www.maplin.co.uk/standard-potentiometers-2205 some thing like this so you could change the resistance as needed?

 

[rayf3262]

Am I correct in understanding that the MAF tells the ECU what the air temerature and density is?

Is it also correct that it does this via a piece of thin wire, which is heated?

Wouldn't it be simple... if you hard the nerve/money to increase or decrease resistance in this wire to 'fool' the ECU into increasing fuel delivery etc?

Or am I looking at this too simplisticly?

Alan

What you need to do is INCREASE the MAF output into fooling the ECU that there is more air than measured by the MAF. More air = increased fuelling... up to about 2500 RPM.
After 2500~3000 RPM the volume of air will swamp the MAF, so at low RPM it will show a significant improvement.
This simple little circuit will do exactly that:

 

[zippy656]

so what will it do above 2500 rpm?

 

[lacroupade]

so wheres the ecu then is it behind the glove box and how hard is it to fit the tunit box then

If you've got a faceift truck, its probably behind the centre dash immediately above (and behind obviously) little cubby hole at the bottom, so centre dash needs to come out, but Tunit give full wiring instructions which depend on which ECU you have (80-odd pins or 120-odd pins.....very roughly LOL)

Am I correct in understanding that the MAF tells the ECU what the air temerature and density is?

Is it also correct that it does this via a piece of thin wire, which is heated?

Wouldn't it be simple... if you hard the nerve/money to increase or decrease resistance in this wire to 'fool' the ECU into increasing fuel delivery etc?

Or am I looking at this too simplisticly?

Alan

There is indeed a £5 resistor solution but its pants and just floods the pump across the rev range as I understand it and is very uneconomical.

In idiot terms, i.e. in a way a dumbo like me can understand it :augie the MAF wire has a current passed through it to heat it. The passage of air over the wire has a cooling effect which changes the resistance of the wire and I think its this signal that gets fed to the ECU.

So when the air is colder, resistance increases, signal goes to ECU which says to itself "aha, colder air, so denser, so more oxygen, so I can squirt more fuel in"...and it does. The opposite happens when the air gets warmer.

You probably notice how they are a tad more sprightly in the winter.

When your MAF wire gets shit-up, as it can if your air filter is inefficient or crapped up, that acts like insulation and reduces the aforementioned effect of colder air. In fact it is likely to make the car thinks its driving in the tropics LOL so would be underfuelling relative to the actual atmospheric conditions.

BUT, in reality these changes are not THAT significant in the scheme of things, but are noticeable if you know your vehicle well.:thumb2

 

[rayf3262]

so what will it do above 2500 rpm?

The volume of air at 2500~3000 RPM will pretty much mean the MAF is maxed out, so answer: not very much, as the ECU pretty much ignores the MAF info after this point.

For what its worth with the circuit as shown the gain is adjustable from about 1.2 to 1.5 times the input voltage.
Example: MAF o/p = 2.5V, AMP o/p = 3.0V to 3.75V. The maximum voltage available from this amplifier would be 5V, so there is no danger of frying the ECU.

 

[TONUP]

So it can be done cheaply, but not effectively. Appreciate the answers though.

Regards

Alan

 

[lacroupade]

So it can be done cheaply, but not effectively. Appreciate the answers though.

Regards

Alan

I think that sums it up, but Ray or Timbo can give more tech detail than my idiot guide

 

[rayf3262]

So it can be done cheaply, but not effectively. Appreciate the answers though.

Regards

Alan

This web page will give you some insight as to what benefits a MAF amplifier will bring to the party.
http://tuning-diesels.com/Mafam/maproject.htm

 

[TONUP]

Thanks. It's an interesting subject, because my T2 could be a bit better with the caravan on the back. I'm not interested in making it faster, but I would like a bit more grunt on the hills and pulling away from junctions etc when towing.

I also do not want to dismantle the dash board to fit a Tunit Box, and I like the idea of having something that can be easily plugged in under the bonnet. Even better if the device is adjustable.

It will be good to hear how the £100.00 eBay boxes perform.

Regards

Alan

 

[lacroupade]

Thanks. It's an interesting subject, because my T2 could be a bit better with the caravan on the back. I'm not interested in making it faster, but I would like a bit more grunt on the hills and pulling away from junctions etc when towing.

I also do not want to dismantle the dash board to fit a Tunit Box, and I like the idea of having something that can be easily plugged in under the bonnet. Even better if the device is adjustable.

It will be good to hear how the £100.00 eBay boxes perform.

Regards

Alan

seriously, the dash out thing is not that hard, just quite a few screws LOL

 

[Timbo_1975]

The volume of air at 2500~3000 RPM will pretty much mean the MAF is maxed out, so answer: not very much, as the ECU pretty much ignores the MAF info after this point.

Wrong. The ECU relies on the MAF voltage after the turbo is spooled to increase fuelling. It is a very basic load signal. Correct though that is maxxed out at about 2500rpm.

There is a map within the ecu that compares maf volts against rpm so that it knows what voltage it should expect from the maf- if it falls outside this envelope then it resorts to limp mode. In this application that window is pretty small, compared to say a VW golf with the same system.

So you cannot just chuck a full load signal down the maf wire and expect the ecu to chuck in a load of fuel.

You can however bolster the maf signal with a little device , but really you should replace the maf and be done with it!

 

[rayf3262]

Wrong. The ECU relies on the MAF voltage after the turbo is spooled to increase fuelling. It is a very basic load signal. Correct though that is maxxed out at about 2500rpm.

There is a map within the ecu that compares maf volts against rpm so that it knows what voltage it should expect from the maf- if it falls outside this envelope then it resorts to limp mode. In this application that window is pretty small, compared to say a VW golf with the same system.

So you cannot just chuck a full load signal down the maf wire and expect the ecu to chuck in a load of fuel.

You can however bolster the maf signal with a little device , but really you should replace the maf and be done with it!

Agreed, I stand corrected; it is not ignored.
It is not just a case of "chucking a full load signal down the MAF wire"
It is not "bolstering" the signal.
It is applying an offset to the original MAF signal, It can never exceed the original MAF output by a significant amount anyhow.
Agreed if you go too far with something of this nature the ECU will spit the dummy on an irregular MAF signal.