Distance between AFM and Turbo housing

[Boost37]

Hey guys,

 

New here, have a question, am making a twisted turbo setup with a kinugawa TD05 25G 3" anti surge inlet turbo, i am wondering if there is a set distance for placing the AFM in front of the turbo housing, as iv heard it can create issues ( no way to delete the AFM as no link with this build). The pipe will be a straight pipe off the front of the turbo. Has anybody played around with this before or have some helpful information about this?

 

Any help is appreciated :)

[pedro]

Not sure on distance but make sure the AFM is well supported..

[pl0x]

Think the RB guys are more versed in it but you may need a bend, a decent distance or a "air straightener" to stop the turbo effecting the afm at idle

[Boost37]

Have you heard of any distance? Iv read a few places saying 300mm?? 

[Loren]

Why can't you use a MAP sensor instead?

[boon]

If you're putting the AFM into a 3" pipe you'll have to tune it anyway to scale the AFM, in which case you need a tunable ECU, which means either a Link if you're in an older car or a reflash which can change you to speed density in a newer vehicle, so regardless you may as well throw the AFM in the bin (or on Trademe, whatever). Trying to do twisted setups with an AFM leads to misery and s*** running and eventually deleting the AFM anyway.

[Boost37]

1 hour ago, boon said:

If you're putting the AFM into a 3" pipe you'll have to tune it anyway to scale the AFM, in which case you need a tunable ECU, which means either a Link if you're in an older car or a reflash which can change you to speed density in a newer vehicle, so regardless you may as well throw the AFM in the bin (or on Trademe, whatever). Trying to do twisted setups with an AFM leads to misery and s*** running and eventually deleting the AFM anyway.

I’m running it on in a legacy BP5 2005. So reflash for sure, but is there a way to do away with it?? Any more info on how to without going to a link. As it’s just a toy for trailing a auto to see how it goes. Person above you said go to MAP sensor... hard to change?

1 hour ago, Loren said:

Why can't you use a MAP sensor instead?

How do I change from AFM to MAP? Simple change over? 

[boon]

I don't know enough about Legacy ECUs to really make an informed comment there; @Andy_Mac will know.

 

As far as I know, with _some_ models you can reflash with what's called a "Speed Density" tune, where the fueling is calculated based on Manifold Air Pressure plus an intake air temperature sensor for compensation. You probably have a stock MAP sensor somewhere near the throttle body, but it would make sense to get an aftermarket one and wire it in on the same wiring the stock one uses.

 

Seriously, AFM with twisted is a bastard of a thing, I think quite a lot of people that insist on the misery of trying to do it go to "blow through" and put it in the intercooler plumbing (assuming you're also going to a front-mount intercooler?)

[Andy_Mac]

It can be done but isn't a simple thing. Think with ECUTEK you can but end up being stuck with one of their tuners. 

 

Or you can theoretically do it opensource. Assume being a ’05 it is prefacelift? This makes it easier as you have a 16bit ECU so you can kinda do it the same way @A_J_T did with his BE. It'll be a matter of merging an existing speed density ROM with yours as your one currently has all the specific table locations which will be different to an existing one. 

 

Facelift has a different method as it is a 32bit ECU that you wouldn't want to really tackle without being extremely clued up With computer programming as none of the JDM ECU’s have been done yet. 

 

An AFM with a 3” intake isn't all that terrible. There's some rule about putting it X many cm behind a bend with an inline flow straightener to get the most consistent results but I've got no idea what it is.

[A_J_T]

Yea I'm very much a 16bit ECU man so I can't really confidently comment on the 32bit side of things. This is a good source of truth though https://www.romraider.com/forum/viewforum.php?f=37 looks like there are a number of 32bit speed density ROMs out there. 

 

If you go with the MAF just make sure you have a good bend 90-degree preferably but just something and basically just get the MAF as far away from the turbo as possible. If I ran a MAF on a twisted setup "which I wouldn't" I would run the intake pipe down into the wheel arch and locate the MAF down in there somewhere. Remembering that you ideally want the MAF 300ish mm away from your pod filter for the same reason as keeping it away from the turbo. It needs clean unturbulent flow to work nicely at low flow / idle. 

 

And as mentioned, going to a 3inch MAF housing will require a MAF rescale which is easy enough on the stock ECU 

Edited March 3, 2020 by A_J_T