Compression?

[orangeirocz28]

I have an 01 Banshee, all stock other than Toomey T-5s and a Moose boost bottle. If I were to pull the head and shave say .025 off, any idea st to what the compression ration would be?

 

Thanks

[2004LEBanshee]

what is your elevation

[orangeirocz28]

500 Ft. a/ sea level

[blowit]

I have an 01 Banshee, all stock other than Toomey T-5s and a Moose boost bottle. If I were to pull the head and shave say .025 off, any idea st to what the compression ration would be?

 

Thanks

 

 

Ratio would be 6.4:1

 

Brandon

[David Keith]

Ratio would be 6.4:1

 

Brandon

 

How did you get 6.4:1 ratio. At sea level, atmospheric pressure is 14.7 psi. & 14.7 times 6.4 = 94.1 lbs.

That doesn't sound right... '01 stock should be 8:1, which is about 120 lbs compression. If you mill off 0.025, there will be an increase in compression by about 10 lbs. Just my opinion.

[370banshee]

if your going to mill it.. just take .030 off.. i believe that about the norm anyway.. if i remeber correctly that gives you around 20.5cc dome. which is pump gas friendly...

[blowit]

How did you get 6.4:1 ratio. At sea level, atmospheric pressure is 14.7 psi. & 14.7 times 6.4 = 94.1 lbs.

That doesn't sound right... '01 stock should be 8:1, which is about 120 lbs compression. If you mill off 0.025, there will be an increase in compression by about 10 lbs. Just my opinion.

 

 

A comp ratio is the delta of two volumes and independent of atmospheric pressures. Pumping or static numbers are theoretical on the books based on 100% cylinder fill which is rarely the case. We have seen many calcs are are close but the ratio will generally be the best way for tuning. The OEM listed the Banshee years ago as a 6.5:1 motor. Most of our measurements hold the banshee around 6.0:1 in stock form. This of course can vary depending on several tolerances.

 

Oh, comp ratios can be calculated as either uncorrected, or corrected. The corrected measurement is a much better way to compare ratios.

Edited August 4, 2007 by blowit