WigglingWaffles

I finally got around to doing a compression test; which I honestly should have done a year ago when I got the car, but I digress.

I got 160 on all cylinders (Except for #4 at 165) but then I realized I did the test without the throttle open
Then I got 180/180/175/165 with the throttle open, I didn't add oil because I figure they're all within Mazda's specs and the engine doesn't act unhealthy at all.

My problem here is that I don't know how to decipher why I have 20psi lower compression on #4, or if its something I should be concerned about. Am I just paranoid or do I have something to fix before proceeding with turbo things?

pdexta

iTrader: (17)

I don't compression test for this exact reason. I know I'm going to turbo the car anyway, so I just assume it's good and go on with my plans. The last thing I want to do is throw some debatable compression numbers that make me start 2nd guessing what I know I'm ultimately going to do anyway.

You could try to test #4 again and see what you get, maybe the tester leaked a little and you'll get a better number.

Otherwise I'd vote to forget about it, add the turbo, and if it breaks sometime down the road then you can fix it.

shuiend

iTrader: (24)

Forget it, boost the car, deal with it if something breaks.

x_25

Mine was off by that much, and a big gain on a wet test (poor rings). Boosted anyway. Have had it up to 9.5psi with no issues.

WigglingWaffles

I have a 1.6 shortnose anyways. Turbo's going in and I'll just see how long it takes to spit some bananas out while saving for a rods only 1.8
Solid plan? Solid plan.

concealer404

iTrader: (3)

Just fuggin' send ittttttttttt

andyfloyd

I boosted my 1.8 with way worse compression numbers, YOLO

sshamrockk

You wont be able to reuse your manifold, and possibly downpipe when swapping to a 1.8.