Speed Density vs. MAF
Thread Starter
Instructor
Joined: Mar 2012
Posts: 122
Likes: 0
From: Alliance OH
Thanks for clarifying that point. Also, I did have a good discussion with my tuner and he pointed out that we were not maxed out on the MAF or the duty cycle on the 63 lb / hr injectors, but we we're at the upper 10-20 % of their operating ranges so he decided to go up on the fuel injector size and switch over to the Speed Density program. He feels confident that he can get it all running fine and I did tell him early on that even with my early goal of 650 WHP was for now that I may want to build a forged motor at some point in a year or so and move up to the 800-900 WHP range, so he likely is setting some things in place for the future build.
I will ask him to come on here and offer up some more detail so I can have some of you who are very experienced in this are have a much higher level exchange than what I can offer.
As always, thanks to all for the good advice and guidance.
Former Vendor
Joined: Mar 2004
Posts: 3,442
Likes: 18
From: Winchester CA
At what point is it desired to switch to Speed Density programming logic vs. the stock MAF programming logic?
On a 2012 GS with an e-Force we maxed out the stock LS3 MAF sensor so we switched to Speed Density programming. It seems archaic in some ways but the HP Tuners program for Speed Density does have a number of expanded ranges in some parameters.
I am not an expert on this so I thought some who are up to speed on this could share their experiences and advice.
Thanks for any good info,
On a 2012 GS with an e-Force we maxed out the stock LS3 MAF sensor so we switched to Speed Density programming. It seems archaic in some ways but the HP Tuners program for Speed Density does have a number of expanded ranges in some parameters.
I am not an expert on this so I thought some who are up to speed on this could share their experiences and advice.
Thanks for any good info,
Last edited by Cunningham Motorsports; Aug 24, 2012 at 12:07 PM.
Racer
Joined: May 2004
Posts: 497
Likes: 3
From: Hafnarfirdi
I‘m still using 100mm LS7 maf and is totally maxed out ( 800-900 RWHP I think) but car is still running grate on it but I need to tune it to the psi I´m running ( I need more maf rum to be able to use the boost controller on higher psi settings without changing the maf table . ) I have not done SD tune. I have seen that you can get up to 125mm maf for the Ford Mustang. I´m surprised that no one is offering bigger maf than 100mm maf house for GM. Me plan is to custom make 115-125mm maf for me car do to that I like tuning with the maf.
I use HP tuner.
Am I wrong ?
Should I change to SD tune?
Sorry if this is not the right trend to post this on since this does not answer your question.:o
I use HP tuner.
Am I wrong ?
Should I change to SD tune?
Sorry if this is not the right trend to post this on since this does not answer your question.:o
Former Vendor
Joined: Mar 2004
Posts: 3,442
Likes: 18
From: Winchester CA
I‘m still using 100mm LS7 maf and is totally maxed out ( 800-900 RWHP I think) but car is still running grate on it but I need to tune it to the psi I´m running ( I need more maf rum to be able to use the boost controller on higher psi settings without changing the maf table . ) I have not done SD tune. I have seen that you can get up to 125mm maf for the Ford Mustang. I´m surprised that no one is offering bigger maf than 100mm maf house for GM. Me plan is to custom make 115-125mm maf for me car do to that I like tuning with the maf.
I use HP tuner.
Am I wrong ?
Should I change to SD tune?
Sorry if this is not the right trend to post this on since this does not answer your question.:o
I use HP tuner.
Am I wrong ?
Should I change to SD tune?
Sorry if this is not the right trend to post this on since this does not answer your question.:o
Life Time NCM #2196
Joined: Sep 2004
Posts: 82,595
Likes: 1,711
From: Converse TX
no way your 2012 gs is out of maf, i have made 900+wheel on that maf without it being maxed out (its got a 15K hz maf table).... especially being arranged in a draw through configuration with an e-force, the HZ will be even lower then lets say in a blow through configuration like with a turbo or centrifugal supercharger... in addition there is plenty of ceiling for fueling per hz in the table as well, so no way to max out the fueling either
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Racer
Joined: May 2004
Posts: 497
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From: Hafnarfirdi
I believe that I´m running 15000 Hz maf. In HP OS General MAF Freaq Patch it is Patched at 15000. Is there any other thing kneaded? My car 2005. I´m at 68 lb/min at 11,200 Hz ( Airflow 67,725 ) at 15 psi above 4500RPM which is max. Am I missing sometime?
Safety Car
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From: TEXOMA
St. Jude Donor '08-'09
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Racer
Joined: May 2004
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From: Hafnarfirdi
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Also you can use the HPT 2.5bar OS, and use a programmable MAF sensor by Abaco. I am using their 4" MAF which has 4 sensing elements, two forward and two rearward. The nice thing about them is that the sensor is totally programmable, not just for scaling but also filtering noisy signals out. This especially helps if you have a cam with a lot of overlap.
Former Vendor
Joined: Mar 2004
Posts: 3,442
Likes: 18
From: Winchester CA
if you still want to use the maf but your hitting a 67.7 lb flow fueling limit, you should think about scaling your flowrate table by 50% will in turn will require you to scale your VE and maf by 50%, that will give you the head way for fueling the maf table.. but you will likely have to touch up your spark tables because now airflow readings in that table will be lower then before so your timing will likely shift up...
Last edited by Cunningham Motorsports; Aug 25, 2012 at 11:21 AM.
Former Vendor
Joined: Mar 2004
Posts: 3,442
Likes: 18
From: Winchester CA
Also you can use the HPT 2.5bar OS, and use a programmable MAF sensor by Abaco. I am using their 4" MAF which has 4 sensing elements, two forward and two rearward. The nice thing about them is that the sensor is totally programmable, not just for scaling but also filtering noisy signals out. This especially helps if you have a cam with a lot of overlap.
Melting Slicks
Joined: Mar 2007
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From: Santa Barbara CA
Le Mans Master
Joined: Oct 2003
Posts: 8,863
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From: PA
St. Jude Donor '08
your car is an 05? your screen name said z06 so i assumed it was an 06 and later.... the 05's are e40 computers, you wont be able to to a 15k maf table with that ecu, you will have to run just a 2.5 bar os and i would suggest going mafless...
if you still want to use the maf but your hitting a 67.7 lb flow fueling limit, you should think about scaling your flowrate table by 50% will in turn will require you to scale your VE and maf by 50%, that will give you the head way for fueling the maf table.. but you will likely have to touch up your spark tables because now airflow readings in that table will be lower then before so your timing will likely shift up...
if you still want to use the maf but your hitting a 67.7 lb flow fueling limit, you should think about scaling your flowrate table by 50% will in turn will require you to scale your VE and maf by 50%, that will give you the head way for fueling the maf table.. but you will likely have to touch up your spark tables because now airflow readings in that table will be lower then before so your timing will likely shift up...
Agreed.....like Ryan said make sure you "push up" the timing numbers that are found in the spark table. Numbers that are found at higher g/per cylinder should be pushed up to lower g/per cylinder. Hopefully you get what I am saying.
Le Mans Master
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From: PA
St. Jude Donor '08
Racer
Joined: May 2004
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From: Hafnarfirdi
It looks like I need to scale me tune. Does it matter if I do 25% or 50% ? So I need to scale the MAF,PE,Injector flow rate vs KPA and the spark table? Any other dustmen’s I need to do. At 17 psi I´m at 11800 hz so I still have another 400 hz left for 20 psi which will be as far as I go.
Thanks.
Thanks.