Crazy Idea No. 467

[Abo Bob]

Ok so I think it was TurboX who modified his AFM making the cross sectional area bigger while keeping the rest intact. I think the idea was to increase the cross sectional area - and hopefully the airflow at the same time - by a set % and then have your injector size increased by the same percentage thus equalling each other out.

Perhaps then give a little tune and away you go.

I think also Autospeed did this.

Anyway, what if, instead of butchering your AFM you put a small bypass tube of a specific size in.

More air would be going through than is being metered so you could conceivably keep your stock AFM when upgrading your turbo.

What do you all think?

[mad082]

could be done if you had an aftermarket ecu.

[StockyMcStock]

a simplified way of looking at it woudl be to imagine a big single turbo with an intake pipe that split into two pod filters, and merged symettrically and identically. then run a single AFM in one of the pipes. you could then theoretically run injectors twice as big and it would run okay. it would probably idle like 5hit and have terrible partial-throttle metering, but it would work with some tuning no worries.

[midnight]

In my opinion there could be a few problems with the system.

If you ran two pods I think you'd also have to consider if there is an equal amount of air going into each of the pods, what happens if one of the pods suffers from a low presssure area under the bonnet whilst the other gets ram air?

alternatively if you split one pipe into 2, you'd have to make sure the air is split equally.

Edited September 1, 2006 by midnight

[T04GTR]

thats a mrt trick,and a sss inductions and pretty much any other afm that cam be pulled apart. good idea but. why get a z32 when you can open up a rb20 or rb26 flow meter

[700HP-GTR33]

thats a mrt trick,and a sss inductions and pretty much any other afm that cam be pulled apart. good idea but. why get a z32 when you can open up a rb20 or rb26 flow meter

Hi there,

I was told that you could trip up the voltage on the AFM's on a GTR to get them to recognise higher flow.

The flow is then calculated differently and entered into the your computer with the Adjustments made by

the Tuner.

This is apparently what they do in Japan and works quite well

Is there any logic or truth in this?

I would love to know.

Cheers

Tekin

[assyrian4evaa]

Hi there,

I was told that you could trip up the voltage on the AFM's on a GTR to get them to recognise higher flow.

The flow is then calculated differently and entered into the your computer with the Adjustments made by

the Tuner.

This is apparently what they do in Japan and works quite well

Is there any logic or truth in this?

I would love to know.

Cheers

Tekin

but that way it will meter air thats NOT getting in and it will run on a richer mix which wont nessasaraly result in a power gain...

correct me if i'm wrong or maybe i didnt understand wat u ment

Edited September 1, 2006 by assyrian4evaa

[PHATR32]

ye auto speed has done it allready. too much screwing around i think

[rb26s13]

this may be an option for those that have maxed out a q45 afm.. get the q45 or z32 probe stuck in the 4inch intake pipe?

[Duncan]

I was told that you could trip up the voltage on the AFM's on a GTR to get them to recognise higher flow.

depends if you think the AFM is a restriction, or if the voltage is hitting max 5v.

If the AFM is a restriction you need a bigger cross section.

If you are hitting max voltage you can:

add resistors in line to the ecu

recore the afm with a different range.

get nismo or similar afms

but you will need a full retune.

And no adam you can't just up injectors by the same % as the increase in cross sectional area it doesn't work like that....depending on boost or load the relationship would be all over the place.

[Abo Bob]

I guess I should have been a little clearer. I meant that in the event that your stock AFM is maxed out, you do this and get a full retune.

As a side issue I was questioning whether the relationship between fuel and air flow was directly proportional, ie would it be close if you upped the injector size by random% and then increased the cross sectional area, using the abovementioned method, by the same percentage?

I guess your answer is that it wouldn't be good enough but I wonder how close it would be?

[GTRgeoff]

Adam, certainly this will work fine as you say. The AFM is a hot wire anemometer, so the volume of air passing is cooling it, needing a greater current to maintain the same temperature. When you increase the volume of air passing in a given time then it requires less current, and so signals less air is passing and therefore less fuel is required (DANGER!! Possibility of leanout and detonation). A retune will simply correct the relationship so you now freer flowing AFM can deliver the air you need.

Rule number one team, if it sounds too good to be true it probably is!

Rule two, you get nothing without having to pay for it some way! So there are no easy ways to increase power dramatically without a decent retune.

JE on Autospeed did the bypass method and adjusted using the Digital Fuel Adjuster.

[CEF11E]

Don't do it. I increased the dia of an RB20 afm by 3.6mm giving me a mass air flow sensing of 18% theoretical greater than standard and tuned the standard ecu and got scary results. on the dyno it was fine and the resolution was fine. in the real world the car would stall and idle badly on completly random occasions.

The VQ map is a tough one to mess around with and is callibrated to 0.01 volts. if you increase/bipass the VQ table is worthless. you will have to redo your entire fuel and timing map.

better off getting a Z32 or Q45. If you are going to max it out go a pair of z32s.

hope this helps.