Airflow meter upgrade

Post by **Lonewolf** » 24 Jan 2005 10:58 am

I was looking at my spare airflow meter and had an urge to make it better, jumping on the net i found that it is called a vane airflow meter which uses a metal flap to see how much air entered, there was another type, called a hotwire airflow meter (MAF) which used a heating element to achieve a similar goal, but posing only a minimal obstacle for the air.

Now i know that using just the hotwire meter on its own would likely not work, as there would be different signals involved, but if some nifty little devices were used, called potentiometers (an adjustable resistor) one should be able to adjust the signals until they matched the stock setup, which would work fine, and on top of flowing better, allow any other MAF to work with no problems simply by adjusting the pots to suit.

Am i crazy? to me it sounds like it should work in theory, but i know sometimes theory and reality dont meet where they should, so if anyone wants to share their insight, i'm all ears, In the meantime i'll be busy with the multimeter and calculator.

Post by **huskyracer** » 24 Jan 2005 02:09 pm

Hi, as I understand it, This is very hard to do, as the flap type meter has a signal voltage to it (5v?) which goes through the pot and back to the ecu as a voltage signal depedant on pot position. The hot wire works by the ecu measuring the current needed to keep the voltage in the wire constant, IE; as more air passes over the wire it is cooled more and requires more current to maintain the voltage drop across it. I have seen converter boxes on other cars to do exactly this but they are quite complicated Not 100% sure my description of hot wire workings is correct pleas someone correct me if I have this horribly wrong

Post by **huskyracer** » 24 Jan 2005 02:14 pm

just a thought, but It may be possible to use a map sensor in the manner you describe Then you could get rid of air flow meters altogether, although you would have to seperate the inlet air temp sensor (and possibly an engine run switch?) from the old airflow meter and use the map sensor to replace just the potentiometer.........

Post by **foggyjames** » 25 Jan 2005 02:21 am

They do indeed use a completely different system. I don't know the details, but they measure different things, so the way they influence the map will be different. Although ultimately a worthwhile mod (probably one to do at the same time as programmable EMS), I think there are better ways to work a B200 first.

cheers

James

Post by **Lonewolf** » 25 Jan 2005 11:24 am

i asked about it today with 2 engine builders and they both said it wouldnt work, one of them suggested as you guys did, putting a MAP sensor in and doing away with the air meter, but a programmable ECU would have to be installed as well ($1000) and then calibrated from the base map... not the sort of money i want to spend on a car i only paid $1300 for.

Post by **foggyjames** » 25 Jan 2005 04:36 pm

One word: Megasquirt. $280 (US), plus mapping. But you can map it yourself if you buy wideband O2 sensor ($250?)

Seriously though, I'd be looking elsewhere - cams, head work, exhaust & header (manifold), etc. A bigger throttle body might be worthwhile?

cheers

James

Post by **shimon340** » 22 Mar 2005 11:17 pm

james is it really 280 dollars?? that 140 quid for an ecu!!! awesome!! i might start cooking up some of my project ideas if this is so cheap...oooh project 340s are a coming!!!

I love the fact you can download data from it to a laptop... just like they do at the races... see the megatune page.....

the big kid in me would love to do datalogging on my car...

hee hee

Post by **foggyjames** » 22 Mar 2005 11:51 pm

$300 for the next batch....and that's assembled. They're cheaper as a built-it-yourself kit. Add some on for a housing, etc, but you get the picture...it's CHEAP!

cheers

James

Post by **shimon340** » 23 Mar 2005 01:36 am

very cheap

thats awesome!!

so you can adjust injection timing and injector duration?

if so.... sounds like a proper engine ecu mapping project... excellent!!!

however, do you guestimate with the ignition timing and then once you have rough idle then start doing real time mapping changes???

sounds like a fantastic system.. especially coz you get to build it yourself.... did you see the megatune page.... cool dials and datalogging..

your whiteblock 340 project sounds amazing....

re the Volvo enthusiasts club.... im in the proces of sorting a webiste for them so soon hopefully you will see stuff online soon

the guy who runs it is a VERY knowledgable and cery friendly guy... he's great to chat to about volvos and really knows his stuff. the VEC could do with some young blood and Im sure kevin (the guy who runs it ) will be more than happy to have new members with new ideas...

take care mate

s 340pw

Post by **foggyjames** » 23 Mar 2005 02:30 am

Yeah, it's exactly like any other programmable EMS. You pop a base idle map in, then get it on the rollers (well....I assume that's how it's done..Huskyracer is the guy to tell us!).

cheers

James

Post by **jtbo** » 23 Mar 2005 07:14 am

Megasquirt can also control ignition if you change base program.

http://megasquirt.sourceforge.net/extra/
Quite big improvement to standard features