I've read alot of threads on compression, and what you should be looking for. Alot of the threads focus on n/a, and the turbo compression numbers seem to be all over the place. So this thread is to provide information for official compression numbers on a turbo engine, providing that someone can answer it.

Here's the results for n/a: (quoted from www.rotaryresurrection.com)

Now we all know those results, but if you take a look through all the compression threads you will notice that s4 t2 compression is lower. Apparently for s4 t2's 90-100 is the healthy zone. Now alot of you are going to say, the compression is lower because of the lower compression rotors. On the resurrection site, it doesnt say anything about strictly n/a's or s5's.

Can someone clarify this up for me?

 

Bump it up. Need to know by tonight.

 

my S4 turbo with unknown mileage provided 115 and 110.

 

So, the people saying that good compression for S4 T2's is around 90-100, dont know what there talking about I guess then.

 

I think that 90 in a TII is still ok. It depends a bit on what kind of apex seals are in it too. I think 110 is about the ideal to look for though, and the closer the better.

As well, I believe as a rule the rear rotor is typically a bit weaker then the front... it wears a little quicker or something.

I know when I bought my TII it had 90 in the front and 60 in the rear... equals a mildly blown engine. However, I drove it for 8 months and about 10,000km's or so before I got around to pulling and rebuilding it. All that was needed was the idle set a little higher than usual and an anti-flood switch wired for warm starts. The engine was still running when I pulled it too. Moral of the story... if the engine is weak it may still last a deciently long time before it goes for good.

P.S. Mine was still running when I finally got around to pulling the engine.

 

anything >80 in my opinion is functioning roperly

 

+1

 

My compression in my s4 TII is 85 front 55 rear :P

 

Compression ratio and static compression numbers gathered on a gauge are not reflective of each other. Low compression ratio engines can still generate about the same static compression pressure as higher compression ratio engines. I have personally measured as much as 125psi on 2 s4 t2 engines, which is also the most I have ever measured in any rotary (accurately). Those numbers stated above and on my site ARE NOT for a particular model of rotary, but for all of them. Even the high compression renesis engines do not make more than about 125psi.