Brigdh

iTrader: (9)

I just ran a compression test with a borrowed TR-01 on my S5 TII and came to two different normalization numbers. Would someone please help me figure out what I did wrong?

For the front rotor, my raw numbers were 81 - 83 - 81 at 273 rpm. I'm at 5430 ft above sea level.

According to the compression calculator at foxed.ca, my normalized numbers are 62.07 - 63.60 - 62.07

Running the calculations by hand, I got 94.225 - 96.225 - 94.225

So, clearly one of the results is wrong.

How I figured it out by hand (so someone can point out my mistake):

Looking at the graph on C-7 for RPM compensation, it looks like at 280 rpm, an 85 psi normalized will actually register as 92.5. So, for every RPM over 250, I should subtract 0.25 psi (7.5 psi gain / 30 rpm gain), or 5.75 psi for my 273 RPM.

That brings my RPM adjusted numbers to 75.25 - 77.25 - 75.25

Now to adjust for altitude. The next graph indicates that an 85 at sea level will register a 71 at 4000 ft above sea level. That comes to a 0.0035 psi drop per foot above sea level. So I added 19.005 psi (0.0035 psi loss per ft alt * 5430 alt).

My final numbers are 94.225 - 96.225 - 94.225 which are about 30psi better than the online calculator.

Since that is the difference between a great engine, and one that needs a rebuild soon, did I screw up my calculations?

Brigdh

iTrader: (9)

After looking things over trying to figure out what was wrong, I ran the numbers through the online calculator again and got a more reasonable 96.82 - 99.21 - 96.82

I must have typed something wrong in the first time to get the low numbers. So, yeah. Clearly user error

misterstyx69

iTrader: (142)

I calculate that you are just "calculating" too much!
With Numbers like that I would be signing off the internet and heading out to drive the **** out of the car!.They are Fine!

SpikeDerailed

iTrader: (7)

Are rotarys not hard to start up there?

Brigdh

iTrader: (9)

Once and a while I've had a hot start flooding issue. Never had any cold start issues.