Yay new compression gauge! Boo bad results!

[My RB25]

So my MAC distributor brought my digital compression gauge today. Very nice, highly recommend it to anyone who's serious about mechanics, stores cyl. compression and everything. But anyway, that's not the issue here lolI got done about an hour ago doing a compression check on all cyl. I got the car in april and was curious to see what'd I get. I think Chiltons and the tech page on nico says like 165? Correct me if I'm wrong please, this is just from memory. I wish I was up there...

Cyl. #1 - 112 m/p (max pressure)Cyl. #2 - 101Cyl. #3 - 118Cyl #4 - 119



Ouch...She has low 160k on it, daily driver. Recently did the timing chain, guides and everything else that comes with that fun fun job, new plugs, wires, cap, rotor (distributor), k&n drop in filter, cleaned maf and throttle body, unorthadox aluminum underdrive crank pulley, 3in cat back w/resonator and 3in resonated test pipe and a few other goodies not related to the engine. She run's great, with the exception of a little rich at times, but what 17 year or car doesn't?

My plan was to go turbo next year and do the work on my vacation. But with those results that got brought to a halt. I was planning on building the head before the turbo. It might give me a look into the problem. I know I'm not mixing oil and anti-freeze. Would my motor be able to handle a turbo, if those numbers increase after the head rebuild or would a bottom end rebuild be in order also? I dont plan on boostin to much..atm

[Florida240sx]

You do the test correctly? Numbers are way low... She should be smoking with those numbers....

[masterbunta]

Unplug all the injectors and unplug the distributor, take out all sparkplugs and install the compression gauge.

With the throttle pushed down all the way, turn engine over untill the needle on the gauge stops increasing, then thats your compression.

[My RB25]

Well i pulled one plug at a time, put it back when I was done. After reading some searched topics I saw more people were going WOT during cranking, something I didnt do. I also didn't disable the injectors, theres no need. I just pulled the coil harness and pulled all the ignition wires. I thought about pulling the injector harnesses also, but I asked my boss, with over 30 years of experience, he said there's no need. Even the instructions on the tool say just to disable the ignition.

I was quite scared when I saw those numbers lol, but I can chirp second, so IDK how bad it can be. Ima do it again today after work, I was rushing yesterday since I was running outta light. I'll keep ya posted.

[slyedog240sx]

you must have wot for the test.The numbers in the fsm are with wot.Low is 151 and standard is 179 iirc.No more than 20% variance i think.

[My RB25]

I ran outta light today, I started doing the LED swap in the HVAC unit. I'll do the test on lunch at work tomorrow, hopefully they'll come back better . Damn getting dark early...

[My RB25]

These numbers make me feel much better, their not perfect, but FAR better than what they were. I still don't plan on boosting before a head build.

Cyl. #1 - 141Cyl. #2 - 149Cyl. #3 - 154Cyl. #4 - 146

As I said before, after I build the head I'll check the numbers to see if boostin is in order. Thanks for tip with WOT, much appreciated.