I've been interested in buying this silver 2005 RX-8 with around 80,000 miles on it for a few weeks now.

The seller claimed to me that the car goes in for regular maintenance, and that last month the car "passed" its compression test.

When pressed further for actual numbers she called her dealer and they gave her a flat number of 7.5 with no units. I told her I needed to know both average compression numbers for each rotor in order to feel comfortable buying the car.

Instead of asking the dealership's service technician herself, she gave me his number and I talked to him today. He is convinced that only one number is needed with Mazda's special compression test kit for rotary engines. He said that there is no need for two numbers, even though I know that is blatantly false.

I know what ranges are acceptable for compression ratios on the 8, but I was just curious if any of you out there have had similar experiences. Is the dealer averaging the two rotors? Is there some test kit that isn't the usual one i've dealt with /seen that only gives one read?

Thanks guys. I searched for this topic and did not find any threads describing this experience I've had. If there is one, I'll delete this thread and pose my questions there. Thanks again for being such an insightful community.

 

Uh. 7.5 is low, passing, but low on the passing spectrum. Alright, apparently my ideas are wrong but whatever. It's still passing, just... meh.

 

RX-8 Help

 

Take it somewhere else? Buy the handheld tester for $350 and do it yourself?

I don't mean to be one of those sexist, girls don't know anything kind of guys, but I would not buy a rotary from a chick. No way

 

Trust me, I've read this, and then I've read this again.

The point of me posting this thread wasn't that I don't understand compression tests, what to expect, and their bands of failure. I needed to see if anyone else had the same experience at some point and found that it was the dealer's ****-up.

At this point I think it's pretty clear this dealer doesn't know what they're doing.

 

Yeah, I considered asking her to take it elsewhere but she wants me to pay for the test in full and I told her upfront I won't do it.

It's not worth the $300 tester in my honest opinion.

 

Well then this can play out a couple of ways. One, you buy the car with the useless info you have and get lucky. Or two, you buy the car with the useless info you have and kick yourself in the *** for making a multi thousand dollar mistake all because of $200. Option three, you don't buy it.

 

I'll take option 3 for $0, Alex.

 

Since any RX8 you buy should be tested, there is a procedure in the Mazda shop manual for what happens in a compression test. If they want to argue, they can argue with that.

 

A word of caution about dealer compression tests. After talking to a Mazda master mechanic about rx8s and compression issues, the dealerships might not give correct results. The tech I spoke with, told me that both of the dealerships he worked for did not have functioning rotary compression testers, and since rotaries haven't been made for awhile, the dealerships see little incentive to replace malfunctioning testers. To top it off some techs are idiots about renesis.
an example.
A friend and I decided to pickup a rx8(our 3rd Rx8) to turn into a track car. It was super cheap because the compression was failing according to a dealership. We planned on rebuilding the engine as part of our budget. It took a long time cranking engine over to start it up cold. hot starts were slow, but it started faster than when engine cold. The starter cranked over this car unusually slow, unhealthy starter slow. It cranked over way slower than my friend's Rx8 that has the original low output stater. So, I installed a new starter, and we are not rebuilding the engine, problem solved.
Did we get lucky? You bet we did. Our other two cars did have to have the engines replaced/rebuilt.
So, when seeking a compression test, ask a ton of questions and have test results in hand. most importantly find shops that have a reputation of rotary know how.

 

Man this post makes me sweat bullets. I was interested in another car that the owner is graciously getting tested tomorrow at a reputable dealer that he has had work on his other rotaries.

I just really hope they do the test correctly and that the numbers come back ok, because I have my heart set on this one. Manual, cleanest RX-8 I've ever seen.

For anyone interested, I told the lady with automatic 05 that I was no longer interested and she almost seemed relieved. Something fishy was for sure going on I feel like. Just food for thought.

 

Autos aren't as fun as 6 speeds anyway.

 

Alright guys, I've been through at least 30 sellers at this point and I just can't seem to get lucky. Every test I have done comes back with a failing rotor. I can't spend any more than $9k-ish on this car in order to have some spill over for maintenance and such.

Is my price range just too low to find an 8 with decent numbers? Even like 06's priced at $7k have been coming back with failing compression or just complete unwillingness to get the numbers for me. I'm sort of at a loss here

 

That sucks, but hang in there. Surely someone has had their motor replaced recently, making an older cheaper car with good compression.

 

Automatic!?!? How was that peice of information not in the original post?...

 

I was just more concerned with the dealer only giving me a single number, and then having the audacity to argue with me about it.

I'm fully aware automatic rx-8's last even less than their manual counterparts.

Btw, I'm pretty sure one of the two rotors on that car was failing, and that's why the dealer was only disclosing one number. The seller dropped her price to like $3k.

 

You could buy mine. We've got an RCTV05 and would be willing to test for you again. Drove it from Baltimore MD to Denver CO and have put 5k miles on it in total this year? something like that. Tested healthy.

 

You want six numbers. Two sets of three - one for each face of two rotors. Assuming the numbers are normalized.

 

If you have the tester and you don't mind taking the time for me, I would be really grateful. PM me with the details on the car if you're serious. Thanks for the offer!

Yep. That's why I was so shocked when a Mazda certified dealer only gave me one number, but I'm pretty sure they were covering for the seller for whatever reason. Maybe they genuinely didn't know what they were doing but at this point that seems unlikely.