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I supported Toymods
Location:
Perth
Registered:
May 2002
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 AFM vs MAP
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Tue, 08 October 2002 01:01
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This was mentioned in another thread about the effectiveness. Much later on down the track, I want to add individual throttle bodies to the 1UZFE I'm going to be putting into my Celica XX. So just out of curiosity, I'm asking everyone's opinion on which is better?
Also, does anyone know which system the BMW M3 and Ferrari's use, AFM or MAP?
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Location:
Montrose, VIC
Registered:
May 2002
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Re: AFM vs MAP
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Tue, 08 October 2002 01:31
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Well I've obviously already spoken in favour of AFM 
That said, you probably want to run yours with individual ram tubes and no plenum, right? In that case an air flow meter isn't really practical. I'm guessing you're also going to do headwork, cams, etc. as well, meaning that it is going to have minimal vacuum. To make it run well you're gonna need to use a decent computer with very fine resolution mapping, and preferably a combination of throttle/MAP input.
BMW use air flow meters, I'm pretty sure Ferrari use Weber Marelli management and is largely throttle based??? correct me if I'm wrong!
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Re: AFM vs MAP
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Tue, 08 October 2002 01:48
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I was thinking using a plenum, I don't want it looking over the top. Plus, there must be some reason for BMW and Ferrari using a plenum, even on their new Enzo.
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Location:
Montrose, VIC
Registered:
May 2002
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Re: AFM vs MAP
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Tue, 08 October 2002 02:00
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Well if there's a plenum involved, AFM
Still, nothing looks more horn than a v8 with 8 polished ram tubes sticking through the bonnet! 'cept a quad cam v8 with polished ram tubes maybe...
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Re: AFM vs MAP
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Tue, 08 October 2002 02:07
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Is it feasible with say...a Haltech to run two AFM's? Would this prevent less restriction than just having one normal one?
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I supported Toymods
Location:
Perth
Registered:
May 2002
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I supported Toymods
Location:
Brisbane, QLD
Registered:
May 2002
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Location:
Sydney, Australia
Registered:
May 2002
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Re: AFM vs MAP
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Tue, 08 October 2002 06:13
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I read somewhere that the restriction of the flap type AFMs are usually overstated, ie they arent as bad as what everyone makes them out to be...
not sure how true or not that is tho.. 
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Toymods Social Secretary
Location:
Sydney
Registered:
July 2002
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Re: AFM vs MAP
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Tue, 08 October 2002 06:21
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when performing head work and especially cam adjustments.. MAP sensors dont tend to have the accurancy or resolution required to accurately read the manifold pressure (since there is less restrictions than from factory), also computers have problems reading such small variances
AFM gives greater resolution and variance hence easier to measure.
this is what ive been told anyway
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Location:
Cabramatta, NSW
Registered:
May 2002
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Re: AFM vs MAP
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Tue, 08 October 2002 08:44
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Yup, you can do a lot to an AFM engine (ie: cams and headwork) and the AFM will take it in its stride.
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Location:
gold coast
Registered:
May 2002
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Re: AFM vs MAP
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Tue, 08 October 2002 11:44
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You get to a point where it does not make a difference tunning wise wether you have MAP or AFM.
To allow flow with minimal restriction the AFM must have a large bore, and therefore will not measure small air flows correctly.
Most NA engines with aftermarket ECU's use TPS based systems, with a 1 BAR MAP sensor for barometric pressure compensation.
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Re: AFM vs MAP
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Tue, 08 October 2002 11:49
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So even with a plenum and head work, ideally, running my NA engine would be better using MAP vs TPS? This is what say BMW or Ferrari or MAserati (as above) would use?
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Location:
North Sydney
Registered:
May 2002
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Re: AFM vs MAP
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Tue, 08 October 2002 11:54
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Ferarri's use afm's. At least the Modena does so id assume the rest do as well.
Flap type afm's arnt used much any more except on cheaper injection setups. Afm's are great but when your going for outright power they pose a restriction especially right before the turbo they can give a couple if inches of vacuum which is fairly hefty. They also allow you to simplify plumbing.
Cant beat em for smoothness on a mildly worked car.
Personally i prefer a very well setup temperature compensated map
sensor.
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Location:
gold coast
Registered:
May 2002
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Re: AFM vs MAP
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Tue, 08 October 2002 12:00
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BTW: You will need to buy a MoTeC M800 if you want to run a AFM based system.
I think it is about the only ECU with a AFM input.
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I supported Toymods
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Perth
Registered:
May 2002
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Re: AFM vs MAP
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Tue, 08 October 2002 12:01
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I'm not after outright power here, I'd like something with a fair whack of power. If Ferrari can get away using AFM's on a Modena, yet can still make nearly 300kW from only 3.6l they can't be posing too much of a restriction for me to worry about.
They would be hot-wire type right?
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Location:
Montrose, VIC
Registered:
May 2002
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Re: AFM vs MAP
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Tue, 08 October 2002 13:22
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When I mentioned AFM's, I wasn't thinking of flap type ones at all, purely hotwire. However, there's also 2 types of hotwire AFMs, the ones with an actual wire, and the 'hot film' ones. The hot film ones are slightly less responsive than the wire ones, but much less bothered by little pieces of dirt etc.
As for restriction, its all about choosing an appropriate piece of gear for the job. Yes a 36mm AFM will place considerable restriction on the airflow of anything greater than a chainsaw. But theres no reason a proper sized one should pose any problem.
The other problem with AFMs is that they can be fiendishly expensive if one does die.
But for greater preciseness, they're about the best of whats available. Hell, even commodores have been using them for a while now!
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Location:
Ipswich
Registered:
July 2002
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Re: AFM vs MAP
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Wed, 09 October 2002 00:35
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Just a thought as i have bugger all knowledge on them. But is it possible to run both a map with a large daimeter afm. This way you could get the best of both worlds?
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Re: AFM vs MAP
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Wed, 09 October 2002 12:20
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Bill perhaps? 
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Location:
North Sydney
Registered:
May 2002
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Re: AFM vs MAP
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Sat, 12 October 2002 03:26
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Microtechs will do map vs tps,
also there are other types of afm's besides hotwire and flap type. Like the Karmon Vortex ones on the 7mgte's.
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Banned by his request
Location:
moved to tamworth
Registered:
July 2002
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Re: AFM vs MAP
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Sat, 12 October 2002 11:00
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MAP EVERY TIME! i have never seen an afm on any race engine and as most of the aftermarket ecu have map{i know it would keep cost down} i think its safe to say MAP all day long. as map reads pressure it knows when airflow has changed. map would be far more reliable and be more acurate.
mick
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Re: AFM vs MAP
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Sat, 12 October 2002 13:09
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Hmm, this is going to be a street car, I've come around in a circle now with these posts. Until now everyone has said AFM is more accurate, especially with cams and stuff, but now I'm really confused
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Banned by his request
Location:
moved to tamworth
Registered:
July 2002
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Re: AFM vs MAP
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Sat, 12 October 2002 21:21
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sorry just read a few more of the posts. MAP systems still use TPS not map vs tps.
dont be confused. just dont listern to people that guess. i didnt get to the top of the ladder by guessing i can assure you,imagine guessing playing with engine that cost well over $130k to build and develop! just a hint for you, which ever way you go just make sure you tune it on a dyno and then on the road as the dyno tunes it to a point the the fine tune has to be done on the street. anyone tells you diffrently, just dosnt know. if you want me to explain i will but you should be able to work out why. just think temp and flow.
mick
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Location:
Melbourne
Registered:
May 2002
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Re: AFM vs MAP
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Tue, 15 October 2002 12:50
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Guy's
can anyone give me some good links to information about the basics of the stuff so I know what the f%c# your talking about. I'm also interested in how these measurement devices are calibrated - i've had a bit to do with instrumentation electronics but not car stuff.
Cheers
David
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