BiG WaNkLeR

I know there are tonnes of these threads and I checked them all and I have a few things I want to clear up.

I have a bone stock S4 T2 that I want to make sure has a good engine before I start dumping money into it.

I did my test like all the instructions said on both rotors, and in both T&L plug holes(I had a plug in the opposite hole while performing the test). Without pressing the release valve on my tester I got 120 psi. But that shows me the highest of the possible 3 faces of the rotor. I want to get the psi of each face, so I got somone to roll the engine over while I hold onto the valve and I got even bounces but only in the 40-60psi range. Some threads are explaining that I'm supposed to see my 100-120p psi bounces when doing this, I'm only getting half. I know by the end I was getting less psi cause I drained the battery but after charging it up I want to test it out again. Another thread mentioned that my small psi bounces is what u want to see when the release valve is held. I'm guessing that different compression testers let out different amounts of air and allow the gauge to only go so high compared to others. idk

Hoping that someone can let me know what I'm doing wrong or what I did was right?

I just want to get on with changing all the fluids and begin modding it

btw, it runs perfectly fine and starts up without any trouble, although it feels it has much power as my n/a did cause my guess is that my exhaust is clogged up so bad it glows red after driving it.

Ice_Wolf

Well, if you look in Banzai's website or Rotary Resurrection's website, you'll see two different ways to compression test. I myself did both of them and followed them exactly as the instructions said. They state in the instructions what you should have for results. Just follow them and you'll be set.

BiG WaNkLeR

I looked at both of those sets of instructions and followed them. The poor man way is obvious, I have lots of pressure coming out of the holes. I want to get some solid numbers to make sure

BiG WaNkLeR

^^^

SpeedOfLife

iTrader: (16)

When you hold the valve open the bounces will not go nearly as high as with the valve closed, what you experienced is normal. Now the fact that you get 120psi , that's simply exceptional. What you want to do to check EACH face though is to just do several runs on each rotor, each time you release the pressure then start again, and if you can count the passes of the seals you might be able to get all three faces tested for sure real quickly.

BiG WaNkLeR

No it didn't though from what I explained, it wouldn't bounce pass 60psi while keeping the valve open while the engine was being spun.

The starter spins that motor too fast to keep track of what face I'm on...I'm sure that's not required.

When I keep the valve closed and spin the engine the compression builds up fast to a max of 120 psi. Within about 1 revolution or a second the guage will read, 90 then 105, then 120 and just stay there. The problem is who knows which face has the 120. the problem is the tester can't reset itself fast enough to get the next reading on the next face.

The 90, 105, 120 description feels like it's building the pressure up gradually as well, should it jump IMMEDIATELY to 120 after the first pass of a rotor face?

I'm pretty sure my engine is in good shape, just being to over cautious.

My guess is that the size of my valve is too large when I open it and lets out too much air to allow it to register a higher reading.

I know this is getting pretty specific, if I had another compression tester it may tell me something different!

wildkats

I also did the RR test and got the exact same results as you. My S4 TII also starts up fine, purs like a kitten, and runs strong.

However, I also found many different numbers from other posts and I'm wondering if it's really ok.

Ice_Wolf

The numbers that you posted indicate a motor in excellent shape. When you hold the valve open and crank, you should be getting around 60 PSI on all 3 faces. That's the exact same number that I got on both front and rear rotors on all 3 faces. The car isn't going to instantly jump to max compression considering it takes a few cranks to build up to max compression. It's the exact same way on a piston engine too. You should be looking for the max compression number and also watch the bounces too. As long as the bounces are even once you get to the 120 mark, that means it's in good condition. The instructions listed on the websites tell you exactly what you should be getting and how to do it.