Is there any reason why a larger MAF is needed for Stage 3 at high altitude?

Blue2 · 11-28-2005, 12:29 PM

My understanding is that MAF sizes are increased to "Scale" the MAF sensor readings for larger airflow so that the sensor limit is not exceeded. Well, I am at 6000' altitude and I have never seen my MAF readings exceed 260 g/s for my stage 3- setup. With an 85mm MAF installed I only see 190 g/s, which with scaling comes out to about 254 g/s with a 1.35 scale factor with the larger MAF. So why do I need a larger MAF if I can only flow 260 g/s at this altitude maximum? Is there any benefit to the larger MAF such as increased volume or should I just stick with the sotck 73mm MAF and stage 3- fueling? TIA

Hal_TT::CBP · 11-28-2005, 12:39 PM

within an operational range(sensor range) so you don't have to reprogram/change the table mappings/transitions on all the load variables.

PSmalls::DoggieStyle · 11-28-2005, 12:47 PM

to get WOT AFR where you want it if you increase injector size without decreasing airflow #s.

Blue2 · 11-28-2005, 12:51 PM

PSmalls::DoggieStyle · 11-28-2005, 12:52 PM

Obviously, you need more fuel to make more power.

Blue2 · 11-28-2005, 12:53 PM

Blue2 · 11-28-2005, 12:55 PM

PSmalls::DoggieStyle · 11-28-2005, 12:55 PM

PSmalls::DoggieStyle · 11-28-2005, 12:57 PM

No need for 85 at altitude if you're seeing those readings. You should probably increase boost, too.

Blue2 · 11-28-2005, 01:00 PM

11-28-2005, 12:29 PM	#1
Blue2 Junior Member Garage is empty, add now Join Date: Aug 2001 Posts: 936	Is there any reason why a larger MAF is needed for Stage 3 at high altitude? My understanding is that MAF sizes are increased to "Scale" the MAF sensor readings for larger airflow so that the sensor limit is not exceeded. Well, I am at 6000' altitude and I have never seen my MAF readings exceed 260 g/s for my stage 3- setup. With an 85mm MAF installed I only see 190 g/s, which with scaling comes out to about 254 g/s with a 1.35 scale factor with the larger MAF. So why do I need a larger MAF if I can only flow 260 g/s at this altitude maximum? Is there any benefit to the larger MAF such as increased volume or should I just stick with the sotck 73mm MAF and stage 3- fueling? TIA

11-28-2005, 12:39 PM	#2
Hal_TT::CBP AudiWorld Super User Garage is empty, add now Join Date: Mar 2000 Posts: 9,755	Don't know why it would... who recommended that? Scaling is only used to keep sensor data within an operational range(sensor range) so you don't have to reprogram/change the table mappings/transitions on all the load variables. __________________ Hal. My German car history... '11 S4 Premium +, 6sp, Ti, Nappa, Carbon, SportDiff, B/O, Nav/Park current Audi '01.5 S4 Shizzle #3 ... purchased 09/03/10, Nogaro/Blue Sport '10 Dodge DS Gen4 Ram 1500(designed by Germans lol) '03 TT 225QC ... sold 09/23/10, Ocean/Sea '01.5 S4 APR Stg3 ... sold 09/10/08, Silver/Silver '01.5 S4 Ordered, Silver/Silver, Lemoned 5mos after purchase '00 996 Cab, Blk/Blk on Silver '98.5 A4 QMS Avant, Santorin/Ecru with blue trim '96 Jetta GLX VR6 '95 Jetta GLX VR6 '92 E36 Coupe - Lemoned 4mos after purchase

11-28-2005, 12:47 PM	#3
PSmalls::DoggieStyle Elder Member Garage is empty, add now Join Date: Jan 2004 Posts: 30,257	Also to be a better match for bigger injectors. Not sure you can pull enough primary fuel to get WOT AFR where you want it if you increase injector size without decreasing airflow #s.

11-28-2005, 12:51 PM	#4
Blue2 Junior Member Garage is empty, add now Join Date: Aug 2001 Posts: 936	So is there any power to be gained with bigger MAF and bigger injectors with limited g/s?

11-28-2005, 12:52 PM	#5
PSmalls::DoggieStyle Elder Member Garage is empty, add now Join Date: Jan 2004 Posts: 30,257	I'm not sure what you're asking.... Obviously, you need more fuel to make more power.

11-28-2005, 12:53 PM	#6
Blue2 Junior Member Garage is empty, add now Join Date: Aug 2001 Posts: 936	So no benefits of full Stage 3 over 3- at altitude?

11-28-2005, 12:55 PM	#7
Blue2 Junior Member Garage is empty, add now Join Date: Aug 2001 Posts: 936	Bigger over stock injectors with 5bar FPR

11-28-2005, 12:55 PM	#8
PSmalls::DoggieStyle Elder Member Garage is empty, add now Join Date: Jan 2004 Posts: 30,257	Good luck making stage 3 power on stock injectors with a 5bar.

11-28-2005, 12:57 PM	#9
PSmalls::DoggieStyle Elder Member Garage is empty, add now Join Date: Jan 2004 Posts: 30,257	Of course there is a benefit. Maybe you should try 83mm (RS4) instead of 85, though. No need for 85 at altitude if you're seeing those readings. You should probably increase boost, too.

11-28-2005, 01:00 PM	#10
Blue2 Junior Member Garage is empty, add now Join Date: Aug 2001 Posts: 936	Won't I still be getting the same g/s with an 83? Whats the difference?

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