AFM before or after charger
Moderator: martauto
Heys guys, I would like to get this right. where is the best place to put the air flow meter on a supercharged m30. I've fitted an eaton m90 on my m30 all is running well but haven't taken i out on the road.
In my opinion I think the AFM should go after the charger to tell the ecu how much fuel to apply but I would like to have the facts.
Any suggestion will be appreciated. Thanks
In my opinion I think the AFM should go after the charger to tell the ecu how much fuel to apply but I would like to have the facts.
Any suggestion will be appreciated. Thanks
Personal opinion from building a corsa 8v turbo with same style afm is your better putting it before the turbo/supercharger, as im not to sure these units are too good under pressure, also i would recomend a rising rate fuel pressure regulator as im guessing your running the standard ecu,
i would have thought you will be very limited running standard management (some1 correct me if im wrong) in regards to mapping
but for a cheap cheap standalone'ish ecu solution i built an m50b25 turbo and used ford falcon xr6 ecu, loom and edis 6 units, this cost me around the £200 mark for all sensors, ecu and coil packs, and loom from ebay australia,
also ended up running edis4 and fiesta rs turbo management on a 2.0 8v turbo corsa, and later on a xu10j2te peugeot turbo engine,
there pretty flexible and easy to map and get chips for,
May be of use to u
but for a cheap cheap standalone'ish ecu solution i built an m50b25 turbo and used ford falcon xr6 ecu, loom and edis 6 units, this cost me around the £200 mark for all sensors, ecu and coil packs, and loom from ebay australia,
also ended up running edis4 and fiesta rs turbo management on a 2.0 8v turbo corsa, and later on a xu10j2te peugeot turbo engine,
there pretty flexible and easy to map and get chips for,
May be of use to u
thanks cakey, are you saying that the standard m30 would be limited even if i get it remap?
I heard of a piggy back fuel management ecu don't know too much about it yet. i will research it
. also i have a set of twin spray injectors from the jaguar xjr6 supercharger 4.0l , i think it's 46lbs but they will fit on the m30. will that help?
I heard of a piggy back fuel management ecu don't know too much about it yet. i will research it
. also i have a set of twin spray injectors from the jaguar xjr6 supercharger 4.0l , i think it's 46lbs but they will fit on the m30. will that help?
I dont know how easy these ecu's are to map to be honest, not sure if u can live map them for boost conditions as they don't have a Map sensor, is you dont get the fueling right at best you will use a bit too much fuel, at worst your going to have a whole in a piston from detonation, it would be a real shame to go to the trouble of supercharging an m30 to have it kill its self after a few miles
In regards to piggy back ecu, do u mean something like a Dastek Unichip Q?
These are pretty good, but only certain places map them and the mapping isnt cheap if i remember,
http://www.ebay.co.uk/itm/Dastek-Unichi ... 4170376b57
Other option is a Greddy eManage, but u want the one with the Map sensor or provisions to run a map sensor,
Depends on your plans to be honest but the 1st thing i would sort is how your controlling everything, as they say, power is nothing without control.
Im planning on supercharging my m20b27 this year and am just starting collecting the bits, it would be awsome to see your when its done or even if you after some help id be glad to lend a hand.
In regards to piggy back ecu, do u mean something like a Dastek Unichip Q?
These are pretty good, but only certain places map them and the mapping isnt cheap if i remember,
http://www.ebay.co.uk/itm/Dastek-Unichi ... 4170376b57
Other option is a Greddy eManage, but u want the one with the Map sensor or provisions to run a map sensor,
Depends on your plans to be honest but the 1st thing i would sort is how your controlling everything, as they say, power is nothing without control.
Im planning on supercharging my m20b27 this year and am just starting collecting the bits, it would be awsome to see your when its done or even if you after some help id be glad to lend a hand.
Hi Matey, i did some digging and research for you, found what looks like a pretty good ''piggy back'' ecu, a lot better than a dastek in my opinion as u can let it control as much or as little as you want, and the price is the best bit,
http://www.ecumaster.com/download/DET3/ ... nglish.pdf
thats the manual and info for it, and if u check them out in ebay ther £140 for the ECU, 20 pin loom, software and usb cable, it also does data logging,
From reading through the manuel and the various wiring diagrams it looks like u could use it as a stand alone for injection and use it to control an edie 6 unit aswell, that will cure your fueling and setup problems.
i know ill be gettin one in a couple of weeks time so ill let you know what its like.
http://www.ecumaster.com/download/DET3/ ... nglish.pdf
thats the manual and info for it, and if u check them out in ebay ther £140 for the ECU, 20 pin loom, software and usb cable, it also does data logging,
From reading through the manuel and the various wiring diagrams it looks like u could use it as a stand alone for injection and use it to control an edie 6 unit aswell, that will cure your fueling and setup problems.
i know ill be gettin one in a couple of weeks time so ill let you know what its like.
Hello Mate, thanks for the info very helpful. i had a look at both systems and i agree that the from ecu master would be better.
I started the car today again and it is running lean also when accelerate the revs remains high after i've lift off, what might that be. i don't think the blow off valve is working properly.
i've done the manual work but now i think i need some advice on getting it to run smoothly or under control.
I'm in Swindon where about are you?
I started the car today again and it is running lean also when accelerate the revs remains high after i've lift off, what might that be. i don't think the blow off valve is working properly.
i've done the manual work but now i think i need some advice on getting it to run smoothly or under control.
I'm in Swindon where about are you?
Last edited by BigJoe on Sat Jan 26, 2013 10:45 pm, edited 1 time in total.
no problems matey, anything i can help with jsut ask,
are u using an eaton supercharger? if so what one? in terms of revs not droping, what dump valve are you using and is it a recirc valve? also if your using an eaton then they have a bypass valve which u can use to stop this problem, also get some WD40 and spray around the inlet manifold and check for leaks 1st
are u using an eaton supercharger? if so what one? in terms of revs not droping, what dump valve are you using and is it a recirc valve? also if your using an eaton then they have a bypass valve which u can use to stop this problem, also get some WD40 and spray around the inlet manifold and check for leaks 1st
blow off valve on inlet of the supercharger. not sure if the accuator is working properly. the blow off valve is set up just the way is was from the factory i haven't changed it.
Last edited by BigJoe on Sun Jan 27, 2013 6:35 pm, edited 1 time in total.

here is the layout. the afm is after the charger but i have no space to fit it before the blower. i have seen the afm fitted after the boost on both super and turbo charged setup. is there any way i could get it to work as it is or a maf from miller.
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ross_jsy
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Most set ups I have seen require the AFM to be positioned before the charger as it needs to measure the air being drawn through it, they don't fair well under pressure.
There is also a limit to how much power the AFM can handle. It would be worth converting to a MAP based set up. Also I wouldn't want to be starting/revving it too much with no mapping work done, of course it's going to run lean, you are pumping air into the engine.
Where is the pipe that goes from the blow off valve actuator connected to?
There is also a limit to how much power the AFM can handle. It would be worth converting to a MAP based set up. Also I wouldn't want to be starting/revving it too much with no mapping work done, of course it's going to run lean, you are pumping air into the engine.
Where is the pipe that goes from the blow off valve actuator connected to?
- Mikey_Boy
- E30 Zone Regular

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- Location: Cheshire - trying to avoid the bling!
^^^^^ +1
You really need to measure the airflow before the charger - that AFM won't work very well under pressure and is of course a restriction to all that lovely boosted air your supercharger has generated.
You can either:
1. Get in touch with Miller and get one of their MAFs for the intake side of your charger (although it looks pretty big hose you have there - their MAF might be too small)
2. Convert your setup to use a MAP (Manifold Absolute Pressure) sensor - this is much more common on turbo and super charged engines.
Good luck!
You really need to measure the airflow before the charger - that AFM won't work very well under pressure and is of course a restriction to all that lovely boosted air your supercharger has generated.
You can either:
1. Get in touch with Miller and get one of their MAFs for the intake side of your charger (although it looks pretty big hose you have there - their MAF might be too small)
2. Convert your setup to use a MAP (Manifold Absolute Pressure) sensor - this is much more common on turbo and super charged engines.
Good luck!
pictures look good, and that is the original bypass valve, if its from an merc or jag then its used on idle, and reverse if i remember,
check to see what position it is in with the car off and throttle open, then start the car and let it idle and see if its in a different position,
and the ross and mikey have confirmed whta i said earlier about the maf, but if you check the spec of that edu master det3 it allows you to convert to either a maf from your original afm, a map sensor or go alpha-N with a different Throttle position sensor, personaly id go for a map sensor then u will have no restriction at all.
check to see what position it is in with the car off and throttle open, then start the car and let it idle and see if its in a different position,
and the ross and mikey have confirmed whta i said earlier about the maf, but if you check the spec of that edu master det3 it allows you to convert to either a maf from your original afm, a map sensor or go alpha-N with a different Throttle position sensor, personaly id go for a map sensor then u will have no restriction at all.
hey guys, i will be be doing a bit more on the project this weekend. but i the mean time i've ordered an aftermarket blow off valve hopefully i receive it before the weekend.
lets talk about weather it possible to remap the standard motronic ecu to run the m30 supercharged setup.
i've had a few suggestions but i'm trying to keep the cost from spiking.
any suggestions please
lets talk about weather it possible to remap the standard motronic ecu to run the m30 supercharged setup.
i've had a few suggestions but i'm trying to keep the cost from spiking.
any suggestions please
Hows this going? did u check the bypass valve was working correctly? i still reckon most cost effective way would be a piggyback ecu, that allows you to map the injectors for the correct fuel flow and get rid of the afm, £135 and a few hours of wiring in and u got yourself a reliable setup.
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e301988325i
- E30 Zone Addict

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there was a good thread on this a couple of years ago. Basically the AFM measures wind speed over a known area and hence volume. The AFM can measure enough volume to feed the engine but not the blower, thus the AFM has to be on the pressurised side.
1) You need to know your injectors are big enough to provide the power you're expecting, knowing how little headroom BMW built in at the time, I doubt they are. Calculations easily available on the web for this. I'm not sure if the mustang injectors were bigger than the M30's but they are a direct fit and both 4-pintle.
2) You need to know your fuel pump can flow enough fuel and provide enough pressure for your intended HP output.
3) Your FPR vacuum/pressure hose needs clamps to hold it on and seal it fully.
4) Once the above is sorted you need a custom map done on the motronic, with the boost upping the fuel pressure to add the extra fuel (zero spool time with a blower so less of an issue than with a turbo in this respect).
This setup should work for about 6-7 psi but after that you need proper management and the sensors that go with it.
ps) this is the budget solution and not the best.
1) You need to know your injectors are big enough to provide the power you're expecting, knowing how little headroom BMW built in at the time, I doubt they are. Calculations easily available on the web for this. I'm not sure if the mustang injectors were bigger than the M30's but they are a direct fit and both 4-pintle.
2) You need to know your fuel pump can flow enough fuel and provide enough pressure for your intended HP output.
3) Your FPR vacuum/pressure hose needs clamps to hold it on and seal it fully.
4) Once the above is sorted you need a custom map done on the motronic, with the boost upping the fuel pressure to add the extra fuel (zero spool time with a blower so less of an issue than with a turbo in this respect).
This setup should work for about 6-7 psi but after that you need proper management and the sensors that go with it.
ps) this is the budget solution and not the best.
I said:
Can anyone suggest how to test if the boot lights are staying on with the boot shut?
e30topless said:
lock the wife in there
Can anyone suggest how to test if the boot lights are staying on with the boot shut?
e30topless said:
lock the wife in there
Thanks for your advice mate. I have a set of Lucas Injector D3165KA they are rated at 42lbs.
http://www.turbobuicks.com/forums/attac ... ectors.jpg
The E39 M5 MAF looks very similar to the ones from miller I wonder if it's worth a try.
http://thumbs3.ebaystatic.com/d/l225/m/ ... 6DD1rQ.jpg
I think my setup will be pushing more the 7 psi. I will find out next weekend as i will be fitting a gauge.
I'm considering using the miller W.A.R chip.
https://www.millerperformancecars.com// ... es/WAR.jpg
Whats you opinion ?
Thanks again
http://www.turbobuicks.com/forums/attac ... ectors.jpg
The E39 M5 MAF looks very similar to the ones from miller I wonder if it's worth a try.
http://thumbs3.ebaystatic.com/d/l225/m/ ... 6DD1rQ.jpg
I think my setup will be pushing more the 7 psi. I will find out next weekend as i will be fitting a gauge.
I'm considering using the miller W.A.R chip.
https://www.millerperformancecars.com// ... es/WAR.jpg
Whats you opinion ?
Thanks again
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e301988325i
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Until you know what boost you're going to run you don't know the lb/hr or air so can't size your injectors, going waaaay too big is not the answer.
You should choose required BHP, calculate the boost required to get said power from siad engine, once you've got your lb/hr then you know what injectors you need, running a gauge on an engine that doesn't work properly is going to end in dead engine.
The M20 miller MAF is a ford item, I've no idea about the one in the M30, I'd say it's most likely Ford as well.
Someone on here tried the W.A.R. chip on an M20, basically unless you have the Miller MAF there are no off the shelf maps for you and you are starting from scratch, there are probably not any maps for a blown M30, there's a forum on Millers website for discussion and sharing of maps. IMHO if you're starting from scratch then start with something decent.
Straight up, have you just bolted a charger onto your engine without working anything out?
You should choose required BHP, calculate the boost required to get said power from siad engine, once you've got your lb/hr then you know what injectors you need, running a gauge on an engine that doesn't work properly is going to end in dead engine.
The M20 miller MAF is a ford item, I've no idea about the one in the M30, I'd say it's most likely Ford as well.
Someone on here tried the W.A.R. chip on an M20, basically unless you have the Miller MAF there are no off the shelf maps for you and you are starting from scratch, there are probably not any maps for a blown M30, there's a forum on Millers website for discussion and sharing of maps. IMHO if you're starting from scratch then start with something decent.
Straight up, have you just bolted a charger onto your engine without working anything out?
I said:
Can anyone suggest how to test if the boot lights are staying on with the boot shut?
e30topless said:
lock the wife in there
Can anyone suggest how to test if the boot lights are staying on with the boot shut?
e30topless said:
lock the wife in there
I've done all the fabrication and installation but now i need to figure out how to control everything. This is gradual process so I have enough time to figure things out with the help of you guys
I will get an m30 package from miller after I've measured the boost this weekend, that should make life a lot easier.
I will get an m30 package from miller after I've measured the boost this weekend, that should make life a lot easier.
i wouldnt take it out for a spin jus to find out what boost its producing, as some1 else on hear said, boost with no form of mapping is going to leave to an expensive mistake, if i where you id get some way of controlling fuelling, some slightly bigger injectors then take it to some1 who is able to map it with a wideband so you can see the AFR, if you run too lean your going to end up with holes in pistons and all sorts,
You can bring it to me in Marlow by the M40.
The appropriate place for MAFs is generaly before the turbo. But as with everything it can be mapped to suit if the maf is in between the turbo and engine.
The appropriate place for MAFs is generaly before the turbo. But as with everything it can be mapped to suit if the maf is in between the turbo and engine.




