Hi! I just got a stage 3 ecu tuning for my rx-8 and the power is great just until 6.5-7k rpm then it feels like that it's really struggling to reach redline, the company who did the tuning never experienced this before and they have remapped 8 different rx8s with perfect results they told me that it's either that the exhaust isn't getting out or that the engine isn't getting enough air

what I have done to my car so far is new coils, new spark plugs, new wires, its a stock exhaust with decat and removed the stock muffler!

Would really appreciate help if someone might have an idea what's wrong..

 

Do you have an running logs of the tuned ecu so we can get an idea of where trims are at, AFR's, etc?

 

Stage 3 ECU tuning? What exactly does that mean in terms of your car?
Generally, when you reach "stage 3", there are other significant hardware changes to a vehicle (stage 1 is usually just software).

6-7k is around the point that some of the intake valves trigger so that's one thing to check into.

 

Hmm

 

Fuel/air ratio is at 1.022 (bank sensor 1) at Cruise says My torque app, mas air flow is at 160g/s when full throttle

Stage 3 meaning in free flowing exhaust, and free flowing intake + ecu software! I have the stock air intake though since I always read on the forum that it's barely upgradeable, is it my intake that's lacking behind after ecu software?

 

Is is possible that its something else than the intake/ exhaust? Since they never had an issue tuning rx8's

 

Stock Exhaust on these cars is small, remember that. You'd be looking at Headers, a real midpipe (BHR, Racing Beat - Either one is awesome.) and a real 3'' back exhaust. As far as intake goes, you aren't wrong about the stock intake being pretty good. You COULD go AEM, but that restricts you to doing things like... not going through drive through car washes and keeping away from puddles.

 

My symptoms is like on this video! Like it wants to rev out faster but it just can't..

What do you think is my best bet since header, intake and exhaust aren't cheap parts at all haha! And the tune is supposed to give 30hk and 30nm just feels like that a 2.5 inch (stock) exhaust should be enough for under 300hp

 

I think your best bet is to properly diagnose/troubleshoot the problem rather than throwing money at it.

But, hey, it's your money so spend away.

If you're going to post data, you'll need to post a full data log, not just one snapshot in time. See if you can log AFR, fuel trims, MAF, RPM, timing, coolant temp, intake air temp, throttle position... Hell, just log everything. Take it from idle to 9k a few times.

The sensors will vary wildly depending on conditions and right foot.

Exhausts really don't get you very much and it's not necessary to re-tune for the overwhelming majority of them (mostly because they don't do a whole lot that would push engine performance outside of OEM expectations). A catback will do almost nothing. A cat delete or high-flow cat might get you a measurable improvement but you probably wouldn't feel it in a blinded study. You've got to go with a pretty aggressive setup from exhaust ports to tailpipes to see an improvement (check out the BHR long-tube header).

Some (most?) intakes actually hurt performance (intake pulse tuning, turbulence around the MAF, etc). Some teams racing RX-8's use the OEM air filter which tells me A) that they have the stock intake, and B) that it's unlikely to be a major restriction.

There are ports in the intake that open at different RPMs.
Secondary Shutter Valve (SSV) 3750 RPM
Variable Fresh Air Duct (VFAD) 5500 RPM
Auxiliary Port Valve (APV) 6000 RPM
Variable Dynamic Effect (VDI) 7250 RPM.

If either or both APV or VDI are malfunctioning, it could cause the loss of power that you're seeing.

Read this thread.
https://www.rx8club.com/series-i-tec.../s-dais-24649/

Mazda tuned the ever loving crap out of the intake system and there isn't much to be gained there in a naturally aspirated setup.

 

Yea you're right feels like it's something else that's the problem, anyhow I just uploaded the data from all the sensors that I can even track and went redline 2-3 times aswell! I don't really know what to look for to be honest haha.. (Open the file in Excel its organized and easy to see everything there)

 

Is this an auto or manual '8?

If it's manual and you went to redline then your data have serious issues because the highest reported RPM is only 6735. You're over 2k short of the real redline.

It it's an auto then some of the things I wrote about S-DAIS don't apply. And also, you're chasing a unicorn.

 

I noticed that aswell, weird huh? It's manual and I did rev to 9k but it didn't/couldn't get that data

 

Any idea what I should do? This came after the tuning, before it was driving without any problems.. Should I take it back to the tuning company and make them "untune" it and see if the problem goes away?

 

It's worth a shot. If they are worth a damn they will have your factory tune saved and it should be a few minutes to switch it back.

 

I'll give it a shot I will keep you updated as soon as I've talked to them/fixed the tune. I really appreciate all the help from you!

 

Lol no. This tuner is clueless/malicious. Take it back so they can go back to stage 1 or whatever.