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Any high HP cars do compression test lately? I did and so should you.

2slowvw

2slowvw

Moderator
Location
VA
Car(s)
2022 Tesla Model 3
Title looks like its something bad i know, but it's not everything checked out within specs. It's such an easy process to do that everyone should do it once in a while to make sure everything is good.


Here are my results:



Cylinder 1: 190
Cylinder 2: 178
Cylinder 3: 180
Cylinder 4: 182


You would like tobe between 160-203 PSI with a max difference of 43.5 PSI between the cylinders.



Procedure I used:


3.4 Compression, Checking
Special tools and workshop equipment required
[emoji815] Spark Plug Removal Tool - 3122B-
[emoji815] Compression Tester Kit - VAG1763-
[emoji815] Compression Tester Kit - Adapter - VAG1381/1-
[emoji815] Compression Tester Kit - Adapter 5A - VAG1381/5A

Test Sequence
Note
[emoji815] Engine oil temperature: minimum 30 °C (86 °F)
[emoji815] Battery voltage at least 12.7 V

  1. Remove the Engine Cover
  2. Remove the ignition coils
  3. Disconnect the fuel injector connectors
  4. Remove the spark plugs with the Spark Plug Removal Tool
  5. Check the compression using the Compression Tester Kit -
    VAG1763- , Compression Tester Kit - Adapter 1 - VAG1381/1-
    and Compression Tester Kit - Adapter 5A - VAG1381/5A-
  6. Operate the starter until the tester no longer indicates a pressure
    increase.
    Compression Pressure​
    New
    11.0 to 14.0 bar (160 to 203 psi)​
    Wear limit
    7.0 bar (101.52 psi)​
    Maximum difference between cylinders 3.0 bar (43.5 psi)
  7. Install the spark plugs.
  8. Install the ignition coils.

    Note
    By separating the connections, DTCs will be stored. After the test,
    check the DTC memory and erase, if necessary.
  9. Delete DTC entries which were generated during testing. Refer
    to Vehicle Diagnostic Tester .
This is the fuel injector connector mentioned in step 3


 
railroader

railroader

Autocross Newbie
Location
Yuma Arizona
I did like 2 weeks ago and it was like 180 across the board, I do one every plug change

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Hoon

Hoon

Autocross Champion
Location
Rhode Island
If my motor has 43.5psi difference, it's coming out.

I forget what my exact results were, but about 185 across the board.
 
Hoon

Hoon

Autocross Champion
Location
Rhode Island
JerseyDrew77 said:
Every plug change!? Don't you think that's a little OCD?
Click to expand...

Not really, it's a 500+whp car at this point and RR has it cranked up to the point where it does see occasional detonation events.

Big power + small engine = tons of maintenance & precautions.
 
2slowvw

2slowvw

Moderator
Location
VA
Car(s)
2022 Tesla Model 3
Diggs24 said:
Awfully nice coat for car working. baller.
Click to expand...




LOL i knew i wouldn't get dirty doing this, and to be honest, my winter attire for super cold weather is limited, this damn cold front ruined my weekend.
 
2slowvw

2slowvw

Moderator
Location
VA
Car(s)
2022 Tesla Model 3
Twist1

Twist1

Autocross Newbie
Location
Breaking Mustang Hearts
OTS Tune WHP/TQ record car (as far as I've been told) - is20 was 191-192 PSI across the board. This was at around 50k miles, tuned since 20k, pushed a little HARD since 30k. Lucas oil upper cyl treatment every other gas fill up, e30 on weekends. One horrific money shift that caused me to test. I will start testing more now that I have more air moving through.

On these motors anywhere 160-190 is probably fine. I used to think that high psi = more HP. But I don't think that is actually the case. I think consistency across the four is the most important thing (IE, 160, 162, 159, 160). I've seen plenty loose PSI Hondas wax 100k 600hp euro coupes...
 
G

Golf7RR

Go Kart Newbie
Location
NE
Thanks. If some folks have port injection so probably have to disconnect those in addition to the direct injection ones too. I think a couple plug s not easy to get to.


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Hoon

Hoon

Autocross Champion
Location
Rhode Island
Golf7RR said:
Thanks. If some folks have port injection so probably have to disconnect those in addition to the direct injection ones too. I think a couple plug s not easy to get to.


Sent from my iPhone using Tapatalk
Click to expand...

Just pull the LPFP fuse and let it idle until it starts to choke.

Good enough
 
jybyrd

jybyrd

Go Kart Champion
Location
Seattle, WA
Hoon said:
Not really, it's a 500+whp car at this point and RR has it cranked up to the point where it does see occasional detonation events.

Big power + small engine = tons of maintenance & precautions.
Click to expand...

Plus, it only takes like 15 extra minutes to test compression. Might as well tack it onto the standard 5k oil+plug+whatever maintenance.

I also do this every time I change the plugs/oil. Peace of mind. If I had 20psi difference across cylinders I certainly wouldn't send it.
 
Twist1

Twist1

Autocross Newbie
Location
Breaking Mustang Hearts
Hoon said:
Just pull the LPFP fuse and let it idle until it starts to choke.

Good enough
Click to expand...

If you just unplug the injectors from housing you don't have to pull fuses.

You can do both to be extra safe.

Also, VW's wear limit is outrageous. If your car is holding only 100 psi of compression motor needs to come out.

Real range should be 145-200
 
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