E30 MAF

[Andy325i]

Hi guys, can anyone shed any light or thoughts onto running an E36 Mass Air Flow meter (hotwire type) on an M20 engine?

Heard once that it couldn't be done, but surely it is "just" a case of interfacing the output from the E36 Maf to what the E30 ECU is expecting as an input for a given volume of air?



Kind regards

Andy

[E30Adam]

It's not quite as straight cut as that.

You need to custom wire it into the existing loom and will then require a piggyback ECU or standalone engine management to run it. Minimum cost of about Ԛ£700.

I've done it with mine and it has it's downsides, throttle response is great but I wouldn't recommend it because of the rough cold running problems it gives due to the lack of IAT sensor.

[Rearwheel_nick]

what takes the price up to Ԛ£700 the standalone management?


also if you dont go to MAF.. what are the downsides of sticking with the standard m20 setup?

[Turbo-Brown]

Surely if you've got a standalone ECU, you can forget all about the MAF etc as it should be mappable for engine speed and load alone.

Mmmmm. Restrictionless

[e30_Turbo]

You can get the MAF for about Ԛ£100 from a breakers and as Adam said then the costs go up, the cheapest is prob the (dastek) unichip, say Ԛ£300....then the couple of hours getting it fitted and setup on the rolling road...easy Ԛ£700, maybe more. Only a piggyback ecu tho.

Stock M20 AFM have proved to the most well suited and M30 Afm's proved to be a complete arse to set up right.

If you go the standalone ecu way you can ditch all the afm/maf etc and use the TPS to monitor/control air in, like Turbo-brown says, Restrictionless. The best way to be.

There are a few options around, MBE/Emerald etc....all very good, but also very expensive, MBE's run into Ԛ£1500+ getting fitted and setup right.
But the fully mappable ones give the most flexability and control and when used in conjunction with a few mods will give the best bhp available from your motor. As long as it is setup correctly.

[Karan]

MAF is great with unichip, throttle response is prob the best i have had on any car i have ever driven, in fact it feels better than my m5's throttle response!

cold runnng probs though, btu u get used to that, just a bit jerky.

[Gunni]

You can get the MAF for about Ԛ£100 from a breakers and as Adam said then the costs go up, the cheapest is prob the (dastek) unichip, say Ԛ£300....then the couple of hours getting it fitted and setup on the rolling road...easy Ԛ£700, maybe more. Only a piggyback ecu tho.

Stock M20 AFM have proved to the most well suited and M30 Afm's proved to be a complete arse to set up right.

If you go the standalone ecu way you can ditch all the afm/maf etc and use the TPS to monitor/control air in, like Turbo-brown says, Restrictionless. The best way to be.

There are a few options around, MBE/Emerald etc....all very good, but also very expensive, MBE's run into Ԛ£1500+ getting fitted and setup right.
But the fully mappable ones give the most flexability and control and when used in conjunction with a few mods will give the best bhp available from your motor. As long as it is setup correctly.

There is a way to monitor the AFM output and have a MAF inline with the AFM and connect the output of the AFM to the piggyback and also the output of the MAF , tune the MAF until both signals are identical

Also .
I retail SMt7 units wich have a build in AFM >> MAF function.
With those you can run any ignition modification to 90Ԛ° advance of retardԚ¨!!
and run any MAP/MAF/AFM and any sized injectors as well,
They ....... blahblah
here is a list of what they can do.
http://www.perfectpower.com/Products/smt7_features.asp
contact me personally for price, I donԚ´t like to advertise on a site I donԚ´t promote,

[E30Adam]

What would be the point in having a MAF inline with an AFM, that would be even worse than with just the stock AFM in place.

[M5pilot]

Other than the cold start issue, the MAF is a good thing. Adams had a bad experience not getting alot of "peak" bhp gain but im sure the torque increase was excellent.

Karan's car benefitted with the MAF alot. Was making 190 something bhp before it was fitted.

Throttle response is superb with MAF on Karans car.

You can buy a secondhand MAF for Ԛ£50 if u shop around, unichip is Ԛ£500 + VAt (inc mapping and setup). A further Ԛ£25 for samco hosing, 1 hours labour to do wiring + small charge for the wiring and connectors. Ideally you want an ITG filter aswell = about Ԛ£60. About Ԛ£700'ish total.

The next cheapest thing is Emerald at around Ԛ£1200 total. No MAF required but there are downsides to not measuring Mass/volume of air. Set up can take a long time and insist on Lambda sensor to be fitted and ideally some sort of load sensor. Torque gains can be HUGE throughout rev range.

For the money ........ MAF is probably your best bet.........he says after throwing Ԛ£1762 at MBE!.......luckily getting every penny back cause i wasnt convinced in the end.

[MONSPORT42]

Just for the record! MAF and ITG filter

MAF great for throttle response. Not so good on very very cold mornings until warm.

[M5pilot]

Very neat job,

Can you get black hosing? IM not keen on the flash electric blue.

Is your car fully mapped now Malcolm? Whats the stats and any flatspots?

[MONSPORT42]

Hi Sal, yep it looks quite good although personally thinks Karan's looks better with the carbon filter cover, but heh, I'm happy.
The car's was in for a full Inspection II and Nigel and Jags did some more tweaking on the dyno (FOC) to help with economy and cruising. Not a flat spot in sight, right up to the red line, which has increased with the new gearbox - my old one cut out into limp home mode before the rev limiter cut in! Of course the gearbox is no longer slipping so that's helped as well.
Didn't ask about max bhp/torque. Last time I had a print out it was showing 237bhp/221ft lbs and that was after 3 hours on the RR so it was very very hot so I expect it was in the 240s under normal conditions. The only thing I can say is it feels better than that! I've unintentionally put it sideways on accelation in the last couple of weeks so something's changed for the better. Drifting with an autobox? that's different!!

[HillclimbE30]

I'm just going to let my ignorance shine out here.
I'm running a 2.7 from Laserchrom, fitted end 2002, superchip, 325 AFM, considering what the next step is and considering MAF & Unichip.
Anyone know where to get this done as it is not exactly a roadside job?

[Jhonno]

Didn't ask about max bhp/torque. Last time I had a print out it was showing 237bhp/221ft lbs and that was after 3 hours on the RR so it was very very hot so I expect it was in the 240s under normal conditions. The only thing I can say is it feels better than that! I've unintentionally put it sideways on accelation in the last couple of weeks so something's changed for the better. Drifting with an autobox? that's different!!

Whats the rest of the spec?! Headwork? Cam? 6 branch?

Sounds like a rather potent motor!!

[MONSPORT42]

Hi Johnno,
My car's in 'Members Cars' in the 2.7 section although the spec's changed some since then. It's a Bexley 2.7 originally built for my old 323i. No six branch (won't fit round the bell housing) or wild cam 'cos it's an auto (kangaroo creep). The cam was the one that was in the Sport when I bought it - think it's probably standard. Head's gas-flowed and ported. MAF and BBTB, ITG filter. Standard manifold and zaust but Scorpion back box. Alpina 16" originals, uprated brakes and M3 bushes have also been added since. And loads of hours on the Dyno. It's been developed over a period of five years and a lot of miles for my style of driving - a fair bit of track time included.

[Andy325i]

It's not quite as straight cut as that.

You need to custom wire it into the existing loom and will then require a piggyback ECU or standalone engine management to run it. Minimum cost of about Ԛ£700.

I've done it with mine and it has it's downsides, throttle response is great but I wouldn't recommend it because of the rough cold running problems it gives due to the lack of IAT sensor.

what is the IAT sensor?

[E30Adam]

It's not quite as straight cut as that.

You need to custom wire it into the existing loom and will then require a piggyback ECU or standalone engine management to run it. Minimum cost of about Ԛ£700.

I've done it with mine and it has it's downsides, throttle response is great but I wouldn't recommend it because of the rough cold running problems it gives due to the lack of IAT sensor.

what is the IAT sensor?

Air Intake Temperature

[Andy325i]

wow that was a quick response Adam!

do you have MSN?

[E30Adam]

wow that was a quick response Adam!

do you have MSN?

Just good timing!

Yeah I've got MSN

[Andy325i]

fancy a chat?

andye30_321bhp@hotmail.com

[Andy325i]

call me silly but, why do you need another ECU? The goal has to be to get the same output from the MAF as the AFM for any given volume of air, but without the restriction of the trap door?

[Ant]

The unichip unit is used with the MAF as a signal converter, the ECU is lookibng for a curved output like the AFM would give, the MAF response is linear and thats where problems arise.

Some of the late late 4 cyl e30s used the e36 setup with a linear response AFM so thats food for thought for our less endowed members

problem with the unichip is its limits are the same as the stock setup in terms of tuning parameters, when you weigh up the costs involved emerald starts to look like a bargain @ c Ԛ£950 if you make up the loom yourself, or adapt the existing to suit.

whatever the justification, anythings gotta be better than the elastic response of the stock AFM, I wonder if moving it closer to the TB would yeild some gains ? M30 engines have the AFM directly in front of the TB and response is better on those.

food for thought ?

[MONSPORT42]

As I understand it, the standard ECU won't read the signals from a MAF so they go into a piggy back chip first.

Just seen Ant's much better reply!

[Andy335Touring]

The next cheapest thing is Emerald at around Ԛ£1200 total. No MAF required but there are downsides to not measuring Mass/volume of air. Set up can take a long time and insist on Lambda sensor to be fitted and ideally some sort of load sensor.

The map on my Emerald was done in about 4 hour's and has run sweetly ever since,i have no lambda or any additional load sensor other than my TPS.When i've fitted my TB's it will be going back to Emerald for Dave Walker to remap it.

<edited>

[Turbo-Brown]

Blimey! You running a 2D map with just the engine speed then?

Suppose the standard 325i is only really 2D mapped on engine speed. As far as I could see, there was only one pulse point on the trigger wheel too when I took my engine apart the week before last.

Did occur to me that MAF hot sensors are supposed to have a burn clean period on shut down. Does the conversion cater for this?

Just a thought really, probably doesn't make much difference in the long run.

[Andy335Touring]

My main load input is the TPS,i was replying to sal who was on about useing a vacum sensor as well as a TPS i think ?

Unless i've missunderstood again ?

I've edited my previous post to make it clearer.

[M5pilot]

Thanks Andy,

I personally think there should be some sort of additional sensor. If yours car is mapped solely on TPS then performance will change as temperature changes. UNless of course Dave has set in some paramters.

I believe a Lamba sensor should defintaley be fitted to keep air/fuel rario in check and a MAP sensor to determine load. Fitting a MAF isnt a bad idea either because its not exactly restrictive. A barometric sensor doesnt do any harm either.

2D maps defintaley have their drawbacks but someone like me was ok with those drawbacks.

[Turbo-Brown]

Fairly sure that the Lambda sensor's only used at idle on the emerald (and lots of other systems) to keep the mixture in check. Once the engine's producing power and you're motoring along, Lambda sensors can't really keep up with the changing mixture.

For a N/A engine, mapping on engine speed and using throttle position as load gives you everything you need in terms of drivability and power. There's not really all that much need for a MAF sensor after that

From what I can tell, my 325 (can't speak for the others) was mapped only on engine speed and position as standard as there doesn't appear to be any kind of load sensor other than the throttle shut/wide open switch which doesn't really count.

[Andy335Touring]

Thanks Andy,

I personally think there should be some sort of additional sensor. If yours car is mapped solely on TPS then performance will change as temperature changes. UNless of course Dave has set in some paramters.

Yes, theres an air intake temp and coolant sensors that have there own mini maps.These mini maps are used to trim the main maps.

The only benifit of fitting a baromic(sp?) sensor is if you live some where hilly like Wales,i noticed mine lost a little performance over the big hills in Wales.Less dense air so i assume i was over fueling slightly.

This is the main soft ware page for the ECU.It all so measures the voltage and compensates for the injectors opening and closing slower at lower voltage's.



The TPS is really handy for me swapping over to the TB's as i don't have a means to use MAP/MAF/AFM unless i make a plenum straight away,i will later on as i want to use the nice cold air from behind the head lamp.

[Andy325i]

Lets start from the begininng....
What is the job, of

A) The Airflow Meter
Obviously it does what it says on the box, so does this mean that when you accelerate, the AFM sends a signal to the ECU telling the injectors to open for a longer duration?

Am I right in thinking that the AFM has a variable resister "sat on top" of the trap door?

Does the AFM have a air temp senser built in?


B) The throttle switch

Is this a variable swich, ie constantly varable output, dependent on the butterfly position, or just a unit to tell the ecu when the car is at Idle and flat out?

[E30Adam]

Hopefully this might answer a few of your questions, based on the Porsche 944 which uses the exact same setup

http://frwilk.com/944dme/

[Andy325i]

cheers for the link adam, but all I get is a pretty picture
Any ideas?

[Andy335Touring]

try this link

http://frwilk.com/944dme/afm.htm

[Andy325i]

Excellent