SD tune
ISIS SUCKS FAT CHOAD
Joined: Oct 2008
Posts: 8,124
Likes: 53
From: Earth, United States
Assuming your tune is optimal based on your current pulley size, your going to need to retune the car whether you go with a smaller or larger pulley from what ever you currently have. I.e. if you have a 3.0 pulley and you change to a 2.85 pulley but make no changes to the tune, the car is going to run leaner (in boost) if you do the aforementioned but go from a 3.0 pulley to lets say a 3.3 pulley the car is going to run richer.
Call it what you want fine tuning re tuning Ect. It still needs to get done either way if you want to keep the same AFR.
Call it what you want fine tuning re tuning Ect. It still needs to get done either way if you want to keep the same AFR.
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Pro
Joined: Apr 2002
Posts: 658
Likes: 4
From: North York Ontario
Ive never been a fan of speed density tuning for a street car.
it is an approximate tune base on a specific ambient condition.
it takes manifold pressure and rpm to estimate fueling and ignores temperature and humidity at operating temperature. If you don't have a 2 bar map for boost you lose the known pressure also.
further SD tuning is done at WOT which is specific for racing not the street. it is easy to control the fueling at a unique set of conditions.
A good MAF tuning requires a competent tuner and a lot of work. what we need is a fuel pressure system that is set at the rail not at the fuel tank and this makes SD even more variable.
but then again I could be wrong.
it is an approximate tune base on a specific ambient condition.
it takes manifold pressure and rpm to estimate fueling and ignores temperature and humidity at operating temperature. If you don't have a 2 bar map for boost you lose the known pressure also.
further SD tuning is done at WOT which is specific for racing not the street. it is easy to control the fueling at a unique set of conditions.
A good MAF tuning requires a competent tuner and a lot of work. what we need is a fuel pressure system that is set at the rail not at the fuel tank and this makes SD even more variable.
but then again I could be wrong.
Safety Car
Joined: Apr 2000
Posts: 4,326
Likes: 140
From: Weatherford, TX
After getting SD tuned for say 25psi, I can run any boost up to 25 and the AFR is always right. When MAF tuned, my MAF was maxed out about 550hp, then fueling was tied to the wideband/RPM and not able to correct itself for different boost.
Drifting
Joined: Apr 2011
Posts: 1,801
Likes: 1
From: Tulsa Ok
Ive never been a fan of speed density tuning for a street car.
it is an approximate tune base on a specific ambient condition.
it takes manifold pressure and rpm to estimate fueling and ignores temperature and humidity at operating temperature. If you don't have a 2 bar map for boost you lose the known pressure also.
further SD tuning is done at WOT which is specific for racing not the street. it is easy to control the fueling at a unique set of conditions.
A good MAF tuning requires a competent tuner and a lot of work. what we need is a fuel pressure system that is set at the rail not at the fuel tank and this makes SD even more variable.
but then again I could be wrong.
it is an approximate tune base on a specific ambient condition.
it takes manifold pressure and rpm to estimate fueling and ignores temperature and humidity at operating temperature. If you don't have a 2 bar map for boost you lose the known pressure also.
further SD tuning is done at WOT which is specific for racing not the street. it is easy to control the fueling at a unique set of conditions.
A good MAF tuning requires a competent tuner and a lot of work. what we need is a fuel pressure system that is set at the rail not at the fuel tank and this makes SD even more variable.
but then again I could be wrong.
Temperature is needed for idle, part and WOT for any scenario. SD is much harder over MAF to fine tune.
Last edited by danieloneil01; Feb 18, 2014 at 06:56 AM.
Melting Slicks
Joined: May 2007
Posts: 2,014
Likes: 48
From: Dayton Ohio
I would have the tune atleast checked if changing boost....
Maybe I am wrong here but if you are going to use the MAF don't you tune the car in SD then turn on the maf and further tune?
I agree with the factory LS1 and LS6 Maf being done around 550. I have a newer LS 3/7 etc credit card style in my car because of this and am fine at 600 wheel. I can see maxing that out later down the road with 700+ wheel maybe? The factory ZR1 uses a Maf doesnt it? What are it's limits?
Maybe I am wrong here but if you are going to use the MAF don't you tune the car in SD then turn on the maf and further tune?
I agree with the factory LS1 and LS6 Maf being done around 550. I have a newer LS 3/7 etc credit card style in my car because of this and am fine at 600 wheel. I can see maxing that out later down the road with 700+ wheel maybe? The factory ZR1 uses a Maf doesnt it? What are it's limits?
Last edited by PEETYZ; Feb 18, 2014 at 09:21 AM.
Racer
Joined: Sep 2013
Posts: 469
Likes: 62
From: coconut creek, fl
I would have the tune atleast checked if changing boost....
Maybe I am wrong here but if you are going to use the MAF don't you tune the car in SD then turn on the maf and further tune?
I agree with the factory LS1 and LS6 Maf being done around 550. I have a newer LS 3/7 etc credit card style in my car because of this and am fine at 600 wheel. I can see maxing that out later down the road with 700+ wheel maybe? The factory ZR1 uses a Maf doesnt it? What are it's limits?
Maybe I am wrong here but if you are going to use the MAF don't you tune the car in SD then turn on the maf and further tune?
I agree with the factory LS1 and LS6 Maf being done around 550. I have a newer LS 3/7 etc credit card style in my car because of this and am fine at 600 wheel. I can see maxing that out later down the road with 700+ wheel maybe? The factory ZR1 uses a Maf doesnt it? What are it's limits?
so it has a smaller 75mm maf and the 2001-up have the bigger 85mm
The c6 and up vettes are easier to tune with larger mafs something to do with more flexibility in the pcms. If you are going SD ditch the maf and replace your map with either a 2bar or 3bar map. Im holding off on SD from what I have read an error code is stored in the pcm and it won't pass emissions
Le Mans Master
Joined: Jul 2010
Posts: 6,013
Likes: 726
I went ahead and purchased an LPE 100mm maf my vette is a 98 model
so it has a smaller 75mm maf and the 2001-up have the bigger 85mm
The c6 and up vettes are easier to tune with larger mafs something to do with more flexibility in the pcms. If you are going SD ditch the maf and replace your map with either a 2bar or 3bar map. Im holding off on SD from what I have read an error code is stored in the pcm and it won't pass emissions
so it has a smaller 75mm maf and the 2001-up have the bigger 85mm
The c6 and up vettes are easier to tune with larger mafs something to do with more flexibility in the pcms. If you are going SD ditch the maf and replace your map with either a 2bar or 3bar map. Im holding off on SD from what I have read an error code is stored in the pcm and it won't pass emissions
Racer
Joined: Sep 2013
Posts: 469
Likes: 62
From: coconut creek, fl