fastest V1 1/4 mi pass?
03-08-2013, 12:14 PM
#84
TECH Fanatic
Kinda wish I had stuck with the twins build myself, honestly. Blower build is much easier though.
03-08-2013, 03:14 PM
#85
Have not dyno'd it yet. Have a new set of worked 317 heads to bring down the compression and boost slightly and trying to decide on a cam. Also plan on going back to a LS7 style MAF system since I seem to be chasing my tail with the 2 BAR OS, which is why I have not done much lately. It's been a real PITA. I plan on heading to the dyno afterwards with both the MAF and 2 BAR systems to see which one performs better.
Kinda wish I had stuck with the twins build myself, honestly. Blower build is much easier though.
Kinda wish I had stuck with the twins build myself, honestly. Blower build is much easier though.
03-09-2013, 10:03 AM
#86
A dialed in SD tune will ALWAYS provide a better response.
I will attempt to explain:
while things are at steady state (or close to it) the MAF gives a very accurate indication of the air density going onto the car. But as soon as you get into a transient condition it can be wildly inaccurate. What do I mean?
Think of a steady state condition, air is moving at x velocity past the MAF into the manifold and ingested. Now you mash on the pedal. The throttle opens. all the air in the manifold and in the intake track before the MAF is now ingested much quicker, but was measured at a slower rate. The maf reads the change (more air) and adds fuel at the same time, but the air volume will not match as the lesser air is what is being used for that brief time. Same when you let off and the throttle shuts but opposite.
This may sound like a small change, but its very noticeable against a dead on SD tune. (experienced with several vehicles)
You can think of this whole thing like a sponge when washing your car.
Hold the dry sponge in your hand over your car and turn the hose on it. For a while there you see a constant rate of water going onto the sponge from the hose but nothing is coming off the sponge onto your car (the sponge is absorbing it). After a while as the sponge saturates you will see the same amount of water running off the sponge as you are applying with the hose.
Now think of the MAF as a flowmeter on the end of the hose, and the engine cylinders as receiving the water coming off the sponge. In this dry sponge example the flowmeter (MAF) doesn't accurately reflect the amount of water running off the sponge until it saturates (reaches steady state), and depending on the size of the sponge it may read high for quite some time.
Now imagine you turned off the hose, for a while there water still flows off the sponge as it slowly dries out. But now the flowmeter (MAF) is reading zero (becuase turned the hose off completely) but your eyes can plainly see that water is still running off the sponge.
This is exactly what happens to the MAF when you have a positive or negative throttle transient, only the sponge is now your intake manifold.
SD is done by calculations, and reference tables for fueling. IAT, RPM, volumes etc...
The throttle changes, the rpm changes the calculations follow them exactly, there are no 'delays', its instant. If all the inputs are good, the SD tune will ALWAYS perform better than MAF, no exceptions.
Chasing tails with SD may indicate some influencing tables are not either disabled or zeroed. An example would be the vehicle is not confirmed in OL., so EQ ratios or Trims are still influencing AFR. or DFCO is still enabled. There are many things that will what is called 'wall fill' cell values being gathered. (transients - or change) as well.
Greg Banish always pushes the use of a Steady State dyno to alleviate all possible variances, of the vehicle itself (e.g. road slope, TPS changes)
Also want to ensure IAT, which is used in these SD calculations is giving the proper value, so heat soak would drift an existing tune.
MAF at low velocity is also very jumpy with the hz (hence why GM uses a blend in the first place). VE for the bottom portion. RedHardSupra has an article about this if anyone is super bored.
http://redhardsupra.blogspot.ca/2010...omparison.html
03-09-2013, 10:43 AM
#87
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I disagree completely...
A dialed in SD tune will ALWAYS provide a better response.
I will attempt to explain:
while things are at steady state (or close to it) the MAF gives a very accurate indication of the air density going onto the car. But as soon as you get into a transient condition it can be wildly inaccurate. What do I mean?
Think of a steady state condition, air is moving at x velocity past the MAF into the manifold and ingested. Now you mash on the pedal. The throttle opens. all the air in the manifold and in the intake track before the MAF is now ingested much quicker, but was measured at a slower rate. The maf reads the change (more air) and adds fuel at the same time, but the air volume will not match as the lesser air is what is being used for that brief time. Same when you let off and the throttle shuts but opposite.
This may sound like a small change, but its very noticeable against a dead on SD tune. (experienced with several vehicles)
You can think of this whole thing like a sponge when washing your car.
Hold the dry sponge in your hand over your car and turn the hose on it. For a while there you see a constant rate of water going onto the sponge from the hose but nothing is coming off the sponge onto your car (the sponge is absorbing it). After a while as the sponge saturates you will see the same amount of water running off the sponge as you are applying with the hose.
Now think of the MAF as a flowmeter on the end of the hose, and the engine cylinders as receiving the water coming off the sponge. In this dry sponge example the flowmeter (MAF) doesn't accurately reflect the amount of water running off the sponge until it saturates (reaches steady state), and depending on the size of the sponge it may read high for quite some time.
Now imagine you turned off the hose, for a while there water still flows off the sponge as it slowly dries out. But now the flowmeter (MAF) is reading zero (becuase turned the hose off completely) but your eyes can plainly see that water is still running off the sponge.
This is exactly what happens to the MAF when you have a positive or negative throttle transient, only the sponge is now your intake manifold.
SD is done by calculations, and reference tables for fueling. IAT, RPM, volumes etc...
The throttle changes, the rpm changes the calculations follow them exactly, there are no 'delays', its instant. If all the inputs are good, the SD tune will ALWAYS perform better than MAF, no exceptions.
Chasing tails with SD may indicate some influencing tables are not either disabled or zeroed. An example would be the vehicle is not confirmed in OL., so EQ ratios or Trims are still influencing AFR. or DFCO is still enabled. There are many things that will what is called 'wall fill' cell values being gathered. (transients - or change) as well.
Greg Banish always pushes the use of a Steady State dyno to alleviate all possible variances, of the vehicle itself (e.g. road slope, TPS changes)
Also want to ensure IAT, which is used in these SD calculations is giving the proper value, so heat soak would drift an existing tune.
MAF at low velocity is also very jumpy with the hz (hence why GM uses a blend in the first place). VE for the bottom portion. RedHardSupra has an article about this if anyone is super bored.
http://redhardsupra.blogspot.ca/2010...omparison.html
A dialed in SD tune will ALWAYS provide a better response.
I will attempt to explain:
while things are at steady state (or close to it) the MAF gives a very accurate indication of the air density going onto the car. But as soon as you get into a transient condition it can be wildly inaccurate. What do I mean?
Think of a steady state condition, air is moving at x velocity past the MAF into the manifold and ingested. Now you mash on the pedal. The throttle opens. all the air in the manifold and in the intake track before the MAF is now ingested much quicker, but was measured at a slower rate. The maf reads the change (more air) and adds fuel at the same time, but the air volume will not match as the lesser air is what is being used for that brief time. Same when you let off and the throttle shuts but opposite.
This may sound like a small change, but its very noticeable against a dead on SD tune. (experienced with several vehicles)
You can think of this whole thing like a sponge when washing your car.
Hold the dry sponge in your hand over your car and turn the hose on it. For a while there you see a constant rate of water going onto the sponge from the hose but nothing is coming off the sponge onto your car (the sponge is absorbing it). After a while as the sponge saturates you will see the same amount of water running off the sponge as you are applying with the hose.
Now think of the MAF as a flowmeter on the end of the hose, and the engine cylinders as receiving the water coming off the sponge. In this dry sponge example the flowmeter (MAF) doesn't accurately reflect the amount of water running off the sponge until it saturates (reaches steady state), and depending on the size of the sponge it may read high for quite some time.
Now imagine you turned off the hose, for a while there water still flows off the sponge as it slowly dries out. But now the flowmeter (MAF) is reading zero (becuase turned the hose off completely) but your eyes can plainly see that water is still running off the sponge.
This is exactly what happens to the MAF when you have a positive or negative throttle transient, only the sponge is now your intake manifold.
SD is done by calculations, and reference tables for fueling. IAT, RPM, volumes etc...
The throttle changes, the rpm changes the calculations follow them exactly, there are no 'delays', its instant. If all the inputs are good, the SD tune will ALWAYS perform better than MAF, no exceptions.
Chasing tails with SD may indicate some influencing tables are not either disabled or zeroed. An example would be the vehicle is not confirmed in OL., so EQ ratios or Trims are still influencing AFR. or DFCO is still enabled. There are many things that will what is called 'wall fill' cell values being gathered. (transients - or change) as well.
Greg Banish always pushes the use of a Steady State dyno to alleviate all possible variances, of the vehicle itself (e.g. road slope, TPS changes)
Also want to ensure IAT, which is used in these SD calculations is giving the proper value, so heat soak would drift an existing tune.
MAF at low velocity is also very jumpy with the hz (hence why GM uses a blend in the first place). VE for the bottom portion. RedHardSupra has an article about this if anyone is super bored.
http://redhardsupra.blogspot.ca/2010...omparison.html
09-03-2013, 12:24 PM
#92
I'm sure most have already seen my best to date (11.9) on 275 all seasons and stock diff with the ebay turbo letting go at the end:
I am getting really excited for all the new stuff thats coming together for the last event of the season at Bandimeere this 13th.
Ford 8.8 TruTrack Rear end courtesy of Creative Steel
Custom Trailing Arms courtesy of Creative Steel
91MM Ceramic BB T4 Turbo
M&H 275/45.18's
ARP 234-4314 Proseries Headstuds (rated to a whopping 190,000psi)
LS9 Head Gasket
Street port of current heads
Hoping for sub 11 sec passes, we shall see...
AND then on the 14th is a standing mile endurance event on a roadcoarse out here, each car runs the mile stretch of track, then circles back around and runs again until eliminated, goes from 8pm to 2am, last one standing gets the whole pot ($50 buy in).
As I am expecting to reach speeds around 200 we are putting a drag chute on in case something goes wrong... (still no other aftermarket safety though)
I am getting really excited for all the new stuff thats coming together for the last event of the season at Bandimeere this 13th.
Ford 8.8 TruTrack Rear end courtesy of Creative Steel
Custom Trailing Arms courtesy of Creative Steel
91MM Ceramic BB T4 Turbo
M&H 275/45.18's
ARP 234-4314 Proseries Headstuds (rated to a whopping 190,000psi)
LS9 Head Gasket
Street port of current heads
Hoping for sub 11 sec passes, we shall see...
AND then on the 14th is a standing mile endurance event on a roadcoarse out here, each car runs the mile stretch of track, then circles back around and runs again until eliminated, goes from 8pm to 2am, last one standing gets the whole pot ($50 buy in).
As I am expecting to reach speeds around 200 we are putting a drag chute on in case something goes wrong... (still no other aftermarket safety though)
09-03-2013, 02:16 PM
#93
I'm sure most have already seen my best to date (11.9) on 275 all seasons and stock diff with the ebay turbo letting go at the end: Single Turbo CTS-V at Bandimeere KBPI Car Show - YouTube
I am getting really excited for all the new stuff thats coming together for the last event of the season at Bandimeere this 13th.
Ford 8.8 TruTrack Rear end courtesy of Creative Steel
Custom Trailing Arms courtesy of Creative Steel
91MM Ceramic BB T4 Turbo
M&H 275/45.18's
ARP 234-4314 Proseries Headstuds (rated to a whopping 190,000psi)
LS9 Head Gasket
Street port of current heads
Hoping for sub 11 sec passes, we shall see...
AND then on the 14th is a standing mile endurance event on a roadcoarse out here, each car runs the mile stretch of track, then circles back around and runs again until eliminated, goes from 8pm to 2am, last one standing gets the whole pot ($50 buy in).
As I am expecting to reach speeds around 200 we are putting a drag chute on in case something goes wrong... (still no other aftermarket safety though)
I am getting really excited for all the new stuff thats coming together for the last event of the season at Bandimeere this 13th.
Ford 8.8 TruTrack Rear end courtesy of Creative Steel
Custom Trailing Arms courtesy of Creative Steel
91MM Ceramic BB T4 Turbo
M&H 275/45.18's
ARP 234-4314 Proseries Headstuds (rated to a whopping 190,000psi)
LS9 Head Gasket
Street port of current heads
Hoping for sub 11 sec passes, we shall see...
AND then on the 14th is a standing mile endurance event on a roadcoarse out here, each car runs the mile stretch of track, then circles back around and runs again until eliminated, goes from 8pm to 2am, last one standing gets the whole pot ($50 buy in).
As I am expecting to reach speeds around 200 we are putting a drag chute on in case something goes wrong... (still no other aftermarket safety though)
I was misinformed about the event on the 14th, NOT a standing mile FML
09-06-2013, 11:10 AM
#95
09-07-2013, 08:23 AM
#96
Launching!
We need to get bob to go to the track again and see what he could run. I knew he was having slave or master issues but if its straightened out im sure he would be down to take another go at it. Ill go and take a couple vids if he does.
