GT Performance Mods 2005+ Mustang GT Performance and Technical Information

Too high boost?!

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Old Aug 16, 2007 | 10:27 AM
  #1  
Croceye's Avatar
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Too high boost?!

I finished my whipple install and got a working tune from Justin at VMP. At first I thought the tune was a bit off since it is leaning out over 4000rpm. After some more test drives and watching all gauges at the same time I saw the boost gauge going above 10 psi to 12-13psi at over 4000rpm. I cannot really understand how this could occur, pulley is the 3.375 supplied with the kit. The only thing I've done to the SC is adding a T-piece on the for the boost gauge...
IC is filled and flowing fine. I tried datalogging from my Autometer sport-comp A/F but couldn't get any voltage on the blue wire output?!

All inputs are appreciated. I'll try to do some T/S tonight (my time, 0630pm now) but I dont know were to start...
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Old Aug 16, 2007 | 11:47 AM
  #2  
RedDragon777's Avatar
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From: McAllen, TX
even though it is a 10psi pulley, the SC makes it's own boost aswell, on my friends lightning the stock pulley was making around 8psi, he added a 10psi pulley and the truck was making somewhere areound 11psi+ because we noticed the guage would hit lower than the 10psi mark and it would stick so now he is going to buy a harley guage pod and adding an autometer guage with up to 30psi just to be safe
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Old Aug 16, 2007 | 12:36 PM
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the SC makes it's own boost aswell
??

You will experience higher or lower boost levels depending on atmospheric conditions. Temperature, humidity and barometric pressue will affect the boost number. A cool day will yield higher boost.
I was seeing 11-12 PSI often when I was on a 10 PSI pulley depending on weather
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Old Aug 16, 2007 | 02:55 PM
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Croceye's Avatar
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Originally Posted by uberPony
??

You will experience higher or lower boost levels depending on atmospheric conditions. Temperature, humidity and barometric pressue will affect the boost number. A cool day will yield higher boost.
I was seeing 11-12 PSI often when I was on a 10 PSI pulley depending on weather
Where are you at? I'm at approx 120ft, 60-70F and today and yesterday it has been a bit humid.
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Old Aug 16, 2007 | 07:45 PM
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I have the Saleen with the 3.6 inch pulley which is supposed to make 7.5/8lbs boost

With Justin's tune I am running 9.5 plus at the top of my pulls - I know there can me a pound variance + or - and it also could just be your car and the blower man
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Old Aug 17, 2007 | 02:43 AM
  #6  
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Originally Posted by Burke0011
I have the Saleen with the 3.6 inch pulley which is supposed to make 7.5/8lbs boost

With Justin's tune I am running 9.5 plus at the top of my pulls - I know there can me a pound variance + or - and it also could just be your car and the blower man
So there could be some differences?! I thought it would be pretty much spot on all the time. Hope Justin can adjust it to give some more fuel over 4000rpm.

Anyone know how to get the datalogging output working? Got a Autometer Sport-Comp A/F. I dont get any voltage on the blue wire.
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Old Aug 17, 2007 | 06:42 AM
  #7  
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Originally Posted by Croceye
So there could be some differences?! I thought it would be pretty much spot on all the time. Hope Justin can adjust it to give some more fuel over 4000rpm.

Anyone know how to get the datalogging output working? Got a Autometer Sport-Comp A/F. I dont get any voltage on the blue wire.
Jim Jr at JDM told me sometimes ytou can have a pound higher than you would expect normally and then factor weather in

I am SURE Justin can tweak your tune. I am running the stock fuel pump and I am perfect on fuel with my setup right till about 6300 with his tweaking my tune
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Old Aug 17, 2007 | 07:39 AM
  #8  
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I too am running the stock fuel pump and have no problems ...
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Old Aug 17, 2007 | 07:44 AM
  #9  
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Originally Posted by 05YellowGT
I too am running the stock fuel pump and have no problems ...
AHHH - the successful Magnacharger install - sweet bro - good numbers!

How many lbs boost?

And you have to let me know your driving impressions with the SC on there now and the 3.73s....... wondering if a 3.55 to 3.73 bump is worth it when you are forced induction
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Old Aug 20, 2007 | 05:52 AM
  #10  
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From: Delray Beach , FL
Thanks man and those numbers are with a conservative tune. I posted the dyno results on the sticky "Your dyno numbers" and you can see the torque is almost a flat line. I don't have a gauge yet , so I not exactly sure what the boost is. I was so excited when I picked it up , I forgot to ask Sam some questions like that , but I pretty sure they put the 3.0" pulley which is rated at about 9.5 psi. As far as the 3.73 gears , I could tell quite a bit of difference from the 3.55 when I first put them on and the car was NA then. I've currently got 255 tires on the rear and they spin and fishtail all the way through 3rd gear if I really get on it , so I definitely need to go to wider tires in the rear ...
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