GolfGTIforum.co.uk
Model specific boards => Golf mk4 => Topic started by: MC_PEA on 16 November 2012, 01:47
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I'v got saab red injectors running at 4bar what maf do I need for it? i'v beening looking a vr6 ones but I just want to know if there are any better ones for the job
Cheers
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U only use the housing! Not the sensor
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when you say they're running at 4 bar, do you mean they are currently, with a stock maf, or they will be when it's mapped?
if the car is currently mapped to a setup, and change on MAF or injectors will require a new map.
I would question why you're running a 4 bar though? unless you're running a turbo that takes the red tops right to their limit on 3 bar?
4 bar FPR's are generally bad news, as they put much more load on the pump. Avoid unless needed.
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Saab reds, vr6 maf and 3 bar fpr was fine for my ko4 agu, 309bhp
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VR6 maf housing is roughly 30% bigger.....so that gives an effective airflow of 241g/s at the limits of the SENSOR (based on 186g/s - cant remember if i was slightly higher)
241 g/s is 301bhp roughly.
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What toby said.
i ran a true 3" MAF but had an uprated fuel pump to suit. That was running 440cc injectors at 3.5bar FRP iirc.
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Vr6 housing is 38% larger, agu sensor is maxed at 187g/s, so an agu sensor in a vr6 housing reading 187g/s is equivalent to 258 g/s, around 320bhp.
It ties in too, on the dyno last weekend I saw 307bhp with a maf peak of 176g/s. on the road I see 186-186g/s so around 320bhp at the limits of the sensor.
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Your in the wrong job nick! :evil:
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He was giving me the same pearls of wisdom earlier lol
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Vr6 housing is 38% larger, agu sensor is maxed at 187g/s, so an agu sensor in a vr6 housing reading 187g/s is equivalent to 258 g/s, around 320bhp.
It ties in too, on the dyno last weekend I saw 307bhp with a maf peak of 176g/s. on the road I see 186-186g/s so around 320bhp at the limits of the sensor.
Me and Nick worked out its 28% larger...
http://www.golfgtiforum.co.uk/index.php?topic=159756.msg1948535#msg1948535
So you must have 3" MAF ID which is 36% larger?
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interseting chris, the quoted figure has been 38% for as long as I can remember, but I'll be honest, I've never felt the need to actually check that!
You're dead right though, just based on the OD's of 70-80mm it's not 38%. D'oh!
What is odd then, is that the sensor does max at 320ish bhp, which would make my numbers correct, but the maths says that you're correct.
Niki has always told me the VR6/AGU clips at 320bhp, and my 307bhp@176g/s falls into that 320bhp clip nicely.
Perhaps the scaling isn't 100% linear?
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Indeed. What does the 3" off a S3 come in at then in terms of % increase? However, I believe the maf sensors are different but not sure if fitment is same/different.
Im not sure how it can read more, maybe the maths arent 100% for the physics?
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the 3'' off an S3 is exactly the same OD as the VR6 housing, so I'd assume the internal dia is the same too?
Housings are different yes, the two bolts which hold the MAF into the housing are 90 degrees rotated from the AGU