C Ya L8r

I just tested my engine and got 93-96psi. The engine has the updated starter and was hot. It seems a little low. I searched and saw around 110-117psi.
I used a standard tester with the valve removed. I am unshure of RPMs.
Any thoughts?

dannobre

iTrader: (3)

Not a real accurate idea of what's going on...there are three rotor faces with different compression values...how they interrelate is very important to the true picture

You need a proper rotary compression tester to get values that mean much

C Ya L8r

With the valve removed you can watch the comperssion of each side. The needle does not stay at peak psi. I was told this was a good way to get an idea of whats going on.
I just want to be shure everything is ok because my full powertrain is up this fall. I only have 22k.

dannobre

iTrader: (3)

Crap data gives you no info....sorry....can't sugar coat it.

You could have 50/50/120 and everything will look cool the way you did it...but have a blown apex seal

Also..the RPM the value is derived at makes a huge difference as well....100PSI at 250 is one thing...but at 330 it is not .....

If you really want to know what the compression is...there is only one right way to do it Use a proper tester

chickenwafer

iTrader: (9)

Most Mazda dealership will only charge 1 hour labor to do a compression test. Complain of lack of power and some do it under warranty. Demand a printout tho.

Like dannobro said, the relationship between the faces and their compression is big. My original renny was replaced because one face on both rotors was low- bad side seal.

C Ya L8r

So the best way to test for low power is dealer, 1/4mi trap speed, or dyno?
I like to go to the dealer well informed. They tend to be scam artists.

dannobre

iTrader: (3)

There are rotary compression testers online that work well...and in the $350 range

A number of us have bought them and they work well....not as easy as the Mazda units....but those are mucho expensive.....

http://rotarydiagnostics.com/

Rotary__Rocket

If you are in Los Angeles, I can refer you to a good rotary tuner shop
I went to the shop couple weeks ago and get a compression test for a good $50

And what kind of compression test did you do, because I got 2 different numbers.....

C Ya L8r

<< I live in minnesota. For the test I used this tester with the check valve removed.

jones75254

iTrader: (2)

Yeah go to dealership and drop $94 to get it done WITH print out. Is worth it for piece of mind. Like others have said though, be sure to get print out or even watch the machine if they let you. Not accurate if the cranking rpm's isnt recorded properly and ALL 3 chamber numbers are taken for each rotor.

C Ya L8r

This is nothing new. Its not as accurate as the dealers tester but you can clearly see each rotor on the tester. You will see a bad seal.
Either way if the peak pressure is to low its bad.
Ex.
http://www.asashop.org/autoinc/dec98/techtips.htm
http://www.youtube.com/watch?v=WTRJm1OAEXc
Any one who has done this have any input. I have other things Id rather buy with $90.
My tests did not look like the one in the link. I had even pulses within 5psi front and rear and all sides. But overall psi seemed low. My scan tool does not support CAN. So no rpm reading, but as stated I do have the new starter.

dannobre

iTrader: (3)

^^ It's no even close enough to get any usable information

If you don't care...so be it....but if you do...pony up the $90

C Ya L8r

Ok Im waiting on bhr for the ignition upgrade.To be honest my power feels good other than when I restart the motor hot (feels like bad heatsoak).I also had the rpms dip low the other day (90deg A/C on). Do you think thats enough reason for the dealer to do the decarb/engine test #01-014-08?

dannobre

iTrader: (3)

If you go in and tell them that it idles and runs rough...and stalls when you are driving it...it should get you a compression/Vac test...and probably the decarb as well...maybe take in a copy of the TSB and very gently ask them to help you out because you are worried.