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Is retune needed when changing pulleys on...

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Old 12-12-2007, 02:33 AM
  #11  
GT Bob
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Default RE: Is retune needed when changing pulleys on...

ORIGINAL: sawyer

Adam at ST Motorsports who knows his sheet told me that he will tune my car for the 18# pully and I can drop to the 14 #er with no tune change, The computer in the car will adjust. This is with the KB 2.6 though.
When you change pulley sizes, you are basically changing the amount of air your stuffing into the cylinders. More air needs more fuel to maintain a good AFR. The computer has some ability to adjust for more airflow, but there is a limit to what it can handle. However, it never has a problem adjusting for less airflow. So by telling the computer it can see up to 18 psi of boost, but only running a pulley that makes 10 or so, the computer can adjust for the lesser amount of airflow. However, there is a trade off in this... Your going to be makin less power and getting less efficiency out of that lesser boost than if you were set for it.

Personally, you've spent how many thousands of dollars on your SC and your car... you really wanna cheap out now and not get a tune that could well save your motor?
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Old 12-12-2007, 07:21 AM
  #12  
sevenleaf
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Default RE: Is retune needed when changing pulleys on...

ORIGINAL: 06Saleen3V

That guy is a moron! Yes you have to retune with a pulley swap on the Saleen. I would order the 3" pulley from Brenspeed

You DO NOT need to retune if you go from the 3.4 to 3.2 but will if you go to the 3.0 pulley. With brenspeeds tune atleast. I am more then happy with the 3.2 pulley there was a huge difference noticed just by swapping the 3.4 with the 3.2 pulley.
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Old 12-12-2007, 07:50 AM
  #13  
sactown
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Default RE: Is retune needed when changing pulleys on...

If you are only dropping one pulley size you should not need to retune the car.
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Old 12-12-2007, 08:48 AM
  #14  
sevenleaf
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Default RE: Is retune needed when changing pulleys on...

ORIGINAL: sactown

If you are only dropping one pulley size you should not need to retune the car.
That's not totally true. When I dropped from 3.6 to 3.4 I needed a retune. Is that one pulley size or two?
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Old 12-12-2007, 12:18 PM
  #15  
modaddict
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Default RE: Is retune needed when changing pulleys on...


ORIGINAL: cheftjpeck

ORIGINAL: 06Saleen3V

That guy is a moron! Yes you have to retune with a pulley swap on the Saleen. I would order the 3" pulley from Brenspeed
actually a tune 4 lets say a 3.6 pulley can also be used 1 pulley size smaller ;ie 3.4 pulley and so on. this comes from 3 tuners, jim jr at jdm, brent at brenspeed and justin at vmp tuning...so for going just 1 pulley size smaller its not needed...if that is the only mod u do...however would I still spend the couple bucks for my own peace of mind..u bet I would...don't save money with a tune when using s/c...but again that's my opinion..
Correct and great advice.
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Old 12-12-2007, 12:26 PM
  #16  
sactown
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Default RE: Is retune needed when changing pulleys on...

every car is different, but it seems that most don't need a retune when dropping one pulley size, and yes 3.4 is the next one down from a 3.6. I personally would retune after dropping pulley sizes just to make sure I am getting as much HP as possible.
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Old 12-12-2007, 12:59 PM
  #17  
sevenleaf
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Default RE: Is retune needed when changing pulleys on...

I should say brent from brenspeed sent me a stage 2 tune originally for 3.6 pulleybrentthen sent me a stage 3 tune for the 3.4 pully brent said they do not retune for the 3.2 pulley but they do for the 3.0

It really depends on how deep your pockets go andif you feel the need to custome tune after each pulley. If i had 500 each time to retune I would be more then happy to retune everytime I changed something. I let the dyno speak for itself.
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Old 12-12-2007, 08:15 PM
  #18  
moosestang
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Default RE: Is retune needed when changing pulleys on...

ORIGINAL: MustangGT0405

I have heard whipple says that their tune for the HO is good for 10psi tune can be used with 8psi or 12psi.

Just food for thought
That is what they told me. I started with the 3.375, then changed to 3.6, then back to 3.375.

No way would I put a 3.0 pulley on a stock motor.
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