More boost with 20% overdrive?

[Jaywebs]

Just installed a 20% overdrive harmonic balancer from innovators west. How much more boost if any she I see with the larger lower?

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[Turbolag87]

2psi

 

[Jackson1320]

20%
If you had 10psi now you have 12psi
If you had 20psi now you have 24psi
Do you see a pattern

 

[Cory S]

I don’t think using 20% as in the amount of boost increase is correct.

If you you reduced the compressor pulley by 20%, it wouldn’t equal the same boost pressure as increasing the damper size 20%.

20% represents 20% more circumference in the belt surface area. You would have to calculate the compressor RPM increase, and use a calculator or comparison to similar pulley ratios.

I believe on the average Coyote, most reported increases with a 20% OD damper is around 4-5psi depending on blower application.

 

[engineermike]

Is this on a PD blower like Whipple or any 2650? If so, my quick and dirty math says 5 psi. The 20% increase is on the total airflow not the boost. Assuming 10 psi as the starting point, then the 1.2 would actually be multiplied by 10+14.7, for a total of 29.6 psia or ~15 psi boost.

 

[Jaywebs]

No. This is on a procharger p1x that as of now is making 17lbs on a 3.55. I was just curious where I was going to be be boost wise ecause I believe I will be running out of injector with the fic 1000's.

 

[engineermike]

You’re at 17 psi *before* the 20% bottom pulley?!

 

[engineermike]

Uh, on a centrif, Google “fan laws”. Pressure goes up by the square of the speed ratio.

17 x (1.2)^2 = 25 psi.

Be careful.

 

[Jaywebs]

Uh, on a centrif, Google “fan laws”. Pressure goes up by the square of the speed ratio.

17 x (1.2)^2 = 25 psi.

Be careful.

Wow. Ok. Didn't realize it was going to be that much. I'm going to reach out to lund and verify sufficient fueling.

 

[Jackson1320]

What size is your supercharger pulley? I can give you a more accurate total boost

 

[Jaywebs]

What size is your supercharger pulley? I can give you a more accurate total boost

3.55

 

[Jackson1320]

If they use the same 20% balancer for all coyotes Right around 20psi. You are over spinning a little but not enough for 25psi for sure

 

[Jackson1320]

With a 3.7 and 20% od I see 15-17psi. The 20% balancer doesn’t add as much as people think. It adds about 20%

 

[WIST2019GT]

I always went with 1 psi per 5% of overdrive. Not sure how scientificly accurate it is but it seems to be close enough for me.

 

[Turbolag87]

its pretty much 20% of whaterver boost ur making at the moment....give or take... so 10 psi would net you 12.... and so on

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