PSI to bar conversion

supchg911 · 11-11-2005, 03:05 PM

Can someone tell me what 7 PSI might convert to in bar? My guage is not metric but most people state their numbers in bar.
Thanks!

walt · walt's Garage

14.7 psi per bar therefore, 7 bar = 103 psi

supchg911 · 11-11-2005, 03:25 PM

Thanks for the lesson Walt!

Henry Schmidt · Henry Schmidt's Garage

7 psi equals .476Bar
10 psi equals .68 Bar
20 psi equals 1.36 Bar
40 psi equals 2.77 Bar
60 psi equals 4.08 Bar
80 psi equals 5.44 bar
5 bar equals 72.52 psi
4 bar equals 58.01 psi
3 bar equals 43.51 psi
2 bar equals 29.01 psi
1 bar equals 14.5 psi

cheers

supchg911 · 03:37 PM

Is there a way to determine the effective compression ratio, considering a 3.2 starts with 9:5 C/R and is supercharged with a maximum of 7 PSI (about .5 bar I've learned!) ?

Henry Schmidt · Henry Schmidt's Garage

3.2 liter

95 bore
74.4 stroke
.040 deck
34 cc dome volume
89 cc chamber volume
8.49 static compression
7 psi boost
14.01 final compression

supchg911 · 11-11-2005, 03:51 PM

Wow! That explains the broken ring lands. Is there a formula that I could use to determine the best C/R for the new pistons?

9dreizig · 11-12-2005, 05:30 AM

Henry, can you show your math?? ( seriously - but didn't want to sound like I was your math instructor) thanks

David · David's Garage

2.7RACER · 11-12-2005, 09:03 PM

9drezig,
I'm not Henry, but using Bruce Andersons formula to calculate compression ratio, I'll show how it works.
The key numbers are V1=cylinder displacement in cc's. in this case 527.36cc's. V2=deck height displacement, 7.09cc's at .040" DH. V3=the head chamber volume, 89cc's. The last key number is the V4=piston dome volume, 34cc's.
Now with these numbers we calculate the volume of everything with the piston at BDC. Add V1+V2+V3 and subtract V4=589.45cc's.
Next we run the piston to TDC and we add V2+V3-V4=62.09cc's.
Compression ratio equals 589.45 divided by 62.09=9.49:1 compression ratio.
With the compression ratio figured out, we just need to know what 7PSI of boost does to the compression ratio. Henry already showed us 7PSI=.476BAR. So we multiply 9.49 time 1.476=14.01, the boosted compression ratio.
Try it yourself. I made a spreadsheet for compression ratio's. It really helped me understand the effect of changing any one value.

9dreizig · 11-13-2005, 11:11 AM

Great thanks for the input ( life is so much easier if you understand the math involved LOL)

Henry Schmidt · Henry Schmidt's Garage

2.7racer nailed the math. Sorry I didn't respond sooner but things get busy around here sometime.

mpdevelopment · 11-14-2005, 07:26 AM

1bar = approx 14.5psi not 14.7psi

sammyg2 · 11-14-2005, 09:55 AM

1 bar = 14.508 psig

Yeah I know, but I crack myself up at least.

supchg911 · 01:23 PM

and if it is approximate, then 14.5 psi = 14.7 psi!

john walker's workshop · 11:21 AM

download josh madison's converter for everything you can think of. free download and keep it on your desktop. http://www.joshmadison.com/software/convert/

9dreizig · 11-15-2005, 12:00 PM

Speaking of converting.. I learned something today here in Germany.. The germans refer to gas economy as say 8 liters,, which means that's the fuel required to go 100Km... kinda simple even though it's inverse notation liters/Km...

einreb · 11-15-2005, 03:02 PM

Quote:

Originally posted by john walker's workshop
download josh madison's converter for everything you can think of. free download and keep it on your desktop. http://www.joshmadison.com/software/convert/

You can also just type "7 psi in bar" into Google search box and it will return...

7 pounds per square inch = 0.482633011 bar

Don't know if it makes GOOG worth $300 a share, but its sorta cool.

-Bernie

mpdevelopment · 11-16-2005, 10:55 AM

Quote:

Originally posted by supchg911
and if it is approximate, then 14.5 psi = 14.7 psi!

No 14.5 psi = 14.5 psi