Rep Power: 325

Ok stock is supposed to be 135psi after 4 cranks at WOT and without ignition firing of course...

I bought a Professional tester... $40 instead of the other for 25....

My engine (all four cylinders!!!) is compressing between 178 and 184psi...

Why would it go up so much? This has managed to confuse the hell out of me. Anyone know what's up?

And yes the car was heated up for over 10 min before I attempted this test.

 
Rep Power: 325

The gauge is dead accurate too. Here's a lil rig I made up. All were on the same pressure source...

So what could this be?

 
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135psi sounds like a low compression turbo motor, is that really what these are supposed to put out? I would think the numbers you have are more normal without looking at a manual I don't have or running down and doing a test on mine. There are a lot more to static figures, but 135 still sounds too low to be the actual rating.

My other car runs "10:1" and is rated between 160-215psi depending on condition of motor. I've seen them with 200,000kms and over 180psi.

 
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I did a Compression Test when I did my head swap and my compression was 160-180 in each cylinder I think.

 
Rep Power: 341

lemme check the shop manual on what stock compression should be

 
Rep Power: 341

the Honda Service manual has the MINIMUM compression at 135psi,

 
Rep Power: 325

I understand that but I don't want much higher than the 135. Technically I'm running high compression pistons right now which just sucks for turbo.

 
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well if ya wanna get technical on it alll..... lol j/k

just Build the block and get over sized lower-compression pistons.... Sleeve it from Darton and yadda yadda yadda then boost the bitch to crazy boost pressures and see what ya get... prob a helluva civic lol, but still a civic

 
Rep Power: 325

I'm currently looking at turbo specialty pistons, arp studs, and a kms gasket. That should be engough for 10psi without alcohol injection. If I do that who knows...

But for now... Is there any quick fix to this? IE, cleaning the tops of the pistons? I've just never seen this before.

 
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are any of the civic models for our motor... the D17's have a lower compression piston available??? I know the GX's had those higher compression pistons that somebody tried once and gave em like 30 more HP on a all-motor D17 so maybe the HX or something has lower compression pistons... research it man!!!!

 
Rep Power: 0

135 is the minimum. that means 160 or so should be right on target for a stock block.

 
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so why would my mechanic have been getting 210 accross the board in my last 3 cylinders? that's confusing ****... lol

 
Rep Power: 811

Stock should be around 135psi. Madwheel, is your head milled any or just stock?I also have a good tester but haven't had time to try it out on the DH head. I'm betting it's around 160 like importracer said.

 
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By our in house tuner (a Honda Guru) he said: "TRY A LEAK DOWN TEST THAT WILL BE MORE ACCURATE. IT IS VERY EASY TO MESS UP A COMPRESSION TEST AND GET WRONG READINGS"

 
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Yea.. that's why my mechanic did... a leakdown test and it show: 90 210 210 210

 
Rep Power: 412

I agree, leakdowns are much more accurate than base compression.... It helps to indicate condition of the rings too....

 
Rep Power: 325

I'll look into it. Thanks guys.

 
Rep Power: 0

I'm not familiar with those numbers in regards to a leak test. Last SnapOn cylinder differential pressure tester I used is 'reccomended' to test at 100psi . 100 keeps it simple as regulator gauge set to 100, whatever the other reads, subtract the two.. you have % leak. i.e. 100 and 98 = 2%. or 100 and 70=30% leak.

you can also screw up leak down test numbers quite easily if you don't know what you are doing.

If 130 is the "minimum" as someone mentioned then the max is likely 40-50psi more. Look forward to getting 135psi 200,000+kms down the road when all the mating surfaces are well worn. I don't see what the problem is, 180psi static compression isn't that awful and I've even run domestics V8s with boost and that much 'static' compression... boost the stock motor with lower boost and tune well. Build something else up in the meantime.

If it isn't broken, don't fix it.