Pulley question/ boost

FLSTANG · Jul 7, 2015

I just have a question maybe someone can help me out. I have the 2.9 Whipple on my 2015 Mustang P/P.I ordered the kit from Lethal Performance with the upgraded throttle body and dual fans. The car is stock other than the blower and a catback exhaust. It put down 650/550 on 93 octane.I was looking at installing a smaller pulley. I believe the kit came with a 3.75 pulley and I wanted to go down to the 3.625. I called Whipple today and spoke with a tech and he was asking me at what boost was the kit putting out. I figured he would already know that being its their kit and their tune. I think it states that it puts 10-11lbs of boost with this kit. I simply want to know if anyone sees any problem with a pulley change with this set up? My car only has 3600 miles so I do not want to screw anything up. Thanks for your help!

Super Werty · Jul 7, 2015

there are a few people running smaller pulleys like that without any issues. However there is always a risk when adding more power like that...I say go for it

ConspicuousConsumption · Jul 7, 2015

Super Werty said:
there are a few people running smaller pulleys like that without any issues. However there is always a risk when adding more power like that...I say go for it

Yeah if it's not your car who cares right? :cheers:

Dyno!

TheHoff · Jul 8, 2015

The pulley diameter should be engraved on the front of the pulley if you want to check what size you have on your car. I think I read somewhere that for every 1/8" diameter change, peak boost changes by 1 psi. Maybe someone from Whipple can confirm. I say go for it. The West coast guys are running the same pulley with 91 Octane. With your 93 octane, you have that extra margin that we don't.

Dat Boi Kumar · Jul 8, 2015

I run a smaller pulley @13# boost no problems

5.0 Steve · Jul 8, 2015

safe bet is to get a custom tune, bap and id1000s

thedalejrfan · Jul 8, 2015

FLSTANG said:
I just have a question maybe someone can help me out. I have the 2.9 Whipple on my 2015 Mustang P/P.I ordered the kit from Lethal Performance with the upgraded throttle body and dual fans. The car is stock other than the blower and a catback exhaust. It put down 650/550 on 93 octane.I was looking at installing a smaller pulley. I believe the kit came with a 3.75 pulley and I wanted to go down to the 3.625. I called Whipple today and spoke with a tech and he was asking me at what boost was the kit putting out. I figured he would already know that being its their kit and their tune. I think it states that it puts 10-11lbs of boost with this kit. I simply want to know if anyone sees any problem with a pulley change with this set up? My car only has 3600 miles so I do not want to screw anything up. Thanks for your help!

As said below, I believe every step down in pulley size equals approx 1 lb of boost increase. I have the same kit being installed right now, and am fully expecting to go down in pulley size as well. Who supplied the tune?

FLSTANG · Jul 8, 2015

Whipple supplied the tune. The question now would be will the car need a new tune with the smaller pulley.

Dat Boi Kumar · Jul 8, 2015

FLSTANG said:
Whipple supplied the tune. The question now would be will the car need a new tune with the smaller pulley.

Yes, whipple supplied a few of use on here with the smaller pulley and said its safe to run with there tune.

FLSTANG · Jul 8, 2015

So I have to send back my PCM to Whipple for the new tune? Not as simple as just changing the pulley?

5.0 Steve · Jul 8, 2015

They won't tune for smaller pulley

Jmeo · Jul 8, 2015

FLSTANG said:
Whipple supplied the tune. The question now would be will the car need a new tune with the smaller pulley.

You do not need a new tune for the smaller pulley.

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Reds197 · Jul 8, 2015

One pound of boost is about 20hp. I think you are safe

Dat Boi Kumar · Jul 8, 2015

Jmeo said:
You do not need a new tune for the smaller pulley.

Sent from my iPhone using Tapatalk

No. The smaller pulley is safe on your current tune.

FLSTANG · Jul 8, 2015

Thanks guys!!! Enjoy your Whipples!!!

Pulley question/ boost

FLSTANG

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Super Werty

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ConspicuousConsumption

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TheHoff

Member

Dat Boi Kumar

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5.0 Steve

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thedalejrfan

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FLSTANG

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Dat Boi Kumar

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FLSTANG

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5.0 Steve

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Jmeo

You said member ;)

Reds197

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Dat Boi Kumar

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FLSTANG

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