2.9 whipple boost

[usmcah-1w]

When I purchased my cobra it had a 2.3 whipple with a 2.9 pulley and it made 19 lbs of boost when on the dyno. It never had a boost gauge just a dyno sheet saying what boost and power it made. I recently installed a 2.9 standard whipple and a speedhut boost gauge. When I went to datalog I seen right at 21 lbs of boost, I am currently on a 3.5 pulley using 93 octane so this is a lot of boost. What would cause the boost to be so high with such a big pulley?


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[01yellercobra]

What lower are you running?

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[usmcah-1w]

Stock lower


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[Four Door SVT]

Most likely clearances inside.

 

[MG0h3]

Wow thats a lot. I know the 2.9 is right around 17 at sea level with the 3.5

Plus you have cams and more CI

 

[luker669]

I have the 2.9 with a 3" pulley and get 17 boost but I'm at 3500 altitude


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[usmcah-1w]

Wow thats a lot. I know the 2.9 is right around 17 at sea level with the 3.5

Plus you have cams and more CI

I also have 1 7/8 headers. The most I have heard of was 20 lbs with a 3.5 pulley but stock engine and headers. I wonder if the gauge could be off.?


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[01yellercobra]

Could be the gauge. Wouldn't hurt to check with another gauge. Are you running cats?

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[91strockercoupe]

i just bought a whipple 2.9 and they sent me a 3.5" pulley to run 17-19 psi i wonder whats going on there.

 

[MG0h3]

I have the 2.9 with a 3" pulley and get 17 boost but I'm at 3500 altitude


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makes me feel a little better. I have a 2.9 upper and see 19 at that elevation. Still baffles me that the 3.75 made 12-13. 3.5 made 15-16 and I only picked up 3 psi by dropping 1/2" Oh well.