Mazda 6 Forums banner
61 - 80 of 239 Posts

·
Registered
Joined
·
1,369 Posts
Discussion Starter · #61 ·
I feel like if you could lock the intake cam to fully advanced you could probably get relatively aggressive with boost. Bottom end components would probably be the only point of weakness, but as of yet that's only speculation. We'll see what comes out as far as bolt ons. Power seems to be my only point of contention with what is already an amazing car and from what I hear from other I think were all on the same page.


Sent from AutoGuide.com Free App
Bottom end is designed pretty strong from what I've seen... The trans would be my #1 worry, and MAY be why Mazda limited the power a bit in our cars instead of tuning it to the max potential. :/
 

·
Registered
Joined
·
747 Posts
Not sure if this is going to be a big deal but I'm about to dyno my car. My buddy races alfa ramoes and has his own personal dyno machine. Hopefully will do it sometime soon.
 

·
Registered
Joined
·
1,998 Posts
So, it appears Orange Virus Tuning has updated their webpage and included some dyno plots.

The one I've attached here is for the 2.5G Skyactiv in our Mazda 6. It has three different setups plotted and the website doesn't say what 2 of them are but the one with the biggest numbers is described by OVtuning as follows:

"...is a Mazda 3 2.5L with Intake / header / full exhaust, both were tuned on 93 octane pump gas. The 2.5L exceptionally exceeds in a very dramatic jump in torque and horsepower. Along with that, the Skyactiv really picks up in the top end, and has a nice flat torque curve through the entire RPM band."

Assuming a standard 10% drivetrain loss for a MTX...that's 226hp and 233lb-ft torque at the flywheel, which is darn close to my original speculation of what was possible of 220hp and 230 lb-ft of torque.


So there is the answer to the question posed by this thread!
 

Attachments

·
Premium Member
Joined
·
1,422 Posts
Very impressive. Have we confirmed that the ECU is switching from Atkinson to Otto at a lower spot in the rev range? I have a hunch this is where a lot of the added power is coming from.
 

·
Registered
Joined
·
488 Posts
Sideways! You're still around? I thought you abandoned the 6 in lieu of something more powerful?

Either way, good to see you're still posting. Loved your creativity!
 

·
Premium Member
Joined
·
1,422 Posts
Sideways! You're still around? I thought you abandoned the 6 in lieu of something more powerful?

Either way, good to see you're still posting. Loved your creativity!
Lol! Thank you! Yep, still around. I don't post as much, but I still watch all the active stuff. My 6 was wrecked, but I still love them and will probably in one of them again in the near future.

I'm back to this car as my daily for now.
 

Attachments

·
Super Moderator
Joined
·
18,359 Posts
@solar365 Those are awesome numbers to see. I agree that this car would be far more exhilarating if it were in that range. Thanks for the info!
 

·
Registered
Joined
·
1,998 Posts
Sweet baby Jesus. That kind of power would put this car right where it needs to be. Any more speculation as to what would be the weak point in the system tough? An added 50lb-ft of torque may be enough to find it.
Also it is highly probable, since it was a mazda 3, that it was the ATX, which with roughly12% drivetrain losses per a stock mazda6 ATX dyno run, that would be 229hp and 236ft-lbs of torque. I'll find out which it was when I talk to the OVT guys. UPDATE: Confirmed I will be the first MTX skyactiv 2.5G tune so the above Dyno is for an ATX. Wow, 230hp and 235lb-ft of torque is pretty good. I guess I'll be finding out if the MTX and clutch can handle this. I'm hopeful that I have the same basic transmission and clutch as the diesel which is good for 300lb-ft of torque rating.


Notice the max RPMs on the dyno plots. All of them run nearly to 7k. Way above the 6.2k stock fuel cutoff.

I agree that you are getting closer to playing with fire here. Although really the gains an a percentage basis aren't too extreme. But somebody needs to run some calcs on piston speed before just bumping the redline to 7k. (EDIT: it's 23.3 meters per second) Piston speeds could be close to a Honda 2k at 9k rpm...(EDIT: 25.2 highest of any production car. Current Honda Accord 2.4 is 22.46 meters/sec! -6800rpm for 99.1mm stroke) And the engineers did comment they removed as much weight as possible from engine internal components to maximize efficiency. I don't know if that means there was excess material in areas that didn't need it before or if the engine internals are simply designed to a lower strength margin than before. I hope it is the former and not the latter.


Engines are designed for maximum fatigue life, not 1 time peak loads, so they should have extra capability if you almost never drive hard or run to redline, but I intend to drive this car for at least 60k, and I'm running to redline on a pretty frequent basis. I wouldn't want to go above 6.5k (EDIT: A piston speed of 21.7meters/second) for a redline and don't want to go above the hp an torque this tune will provide, ending up with a slipping clutch or blown engine.


I think 220hp and 230lb-ft of torque will be just fine. At 3050lbs my car will be as fast or faster than its peers with V6 and turbo 4s except maybe the Honda and Camry by a few tenths.


But this does make me question why would you hassle with an e-supercharger if you are already at those power levels? Trying to break something. For sure if you have an MTX your clutch wouldn't handle it and there are no high performance clutch options available. I could see somebody doing an e-supercharger with everything else stock, so they can keep factory sound levels. That would make sense, but I don't think it is wise to push this engine to say 250-280hp and 280-300ft-lbs of torque with all the mods for that dyno plot plus an e-supercharger. That's really, really pushing it, but somebody inevitably will do it.
 

·
Registered
Joined
·
1,998 Posts
Very impressive. Have we confirmed that the ECU is switching from Atkinson to Otto at a lower spot in the rev range? I have a hunch this is where a lot of the added power is coming from.
I don't know.


I intend to have a pretty thorough discussion with the OVT guys when getting my tune, so I'll let people know what I find out.
 

·
Registered
Joined
·
1,319 Posts
this sounds like a zoom zoom boom moment eminent.
 

·
Registered
Joined
·
1,369 Posts
Discussion Starter · #72 ·
solar, solar, solar!!!... LOL.

100% interested in a tune now... and effects like MPG (just because LOL)
230HP is MUCH better :D
Looks to be right on par with what he had speculated before about 200WHP being the gain level.
 

·
Registered
Joined
·
462 Posts
Sadly, the graph posted will not relate what so ever to our cars. The Mazda3 Skyactive 2.5 has a totally different exhaust manifold than ours.
I believe the one tested was an early model with a replacement manifold.
Our setup looks totally different and while it looks great and the design was made specifically for evacuation/heat removal, it also has an ugly, power robbing cat plumbed into it.
The majority of 6 owners here wont touch that manifold and will only be at most replacing the rear muffler. It would be nice if someone would make a system that gets rid of at least the second cat (high flow replacement) and a straighter flowing street-able (not overly loud) system with zero drone.

Don't get me wrong though, I'd be happy to be second in line for this tune but I fully understand that without a full engine back exhaust the numbers he posted are something we as "6" owners will never achieve.

I'd be super happy if I'm made to eat my words though!!!

Solar: is that graph shown wheel or crank HP?
 

·
Registered
Joined
·
1,998 Posts
Dave,
The graph is at the wheels.

The quote I included from OVT is that the entire exhaust was redone, including headers, so the essence of your statement could be valid, but I don't think there is any difference in the factory 2.5 skyactive headers between the 3 and the 6. They both have the same emissions requirements and should have the same supercomputer designed 4-2-1 headers with a precat shoved in there at the end of them. The factory specs for hp and torque are the same.

It really depends on the car to see what difference aftermarket headers make (5-15hp), and that was always vs a stock cast iron manifold, LoL. I know the guys at dynotronics said the factory headers are hurting top end performance which isn't too suprising since the headers are for minimizing knock for two of the cylinders and would be tuned for fuel economy/torque not top end power, but still, maybe only 5hp?

Look at the rpm of peak power from the plot illustration its basically at the factory redline. A bunch of that could be attributed to the shorter aftermarket intake and the tune, but likely some of it is a top end tuned custom header.

So real world I would think with the factory headers the 2.5G would make about 215-220hp max instead of 225-230 and about the same peak torque as the plot.
 

·
Registered
Joined
·
1,998 Posts
If you want to know whats really cool about this engines potential is that 230+ lb-ft of torque from a naturally aspirated 2.5L gasoline engine. That's a specific torque of 94lb-ft/liter. That is off the charts! And it's just a 4cylinder! not a V8 or V12 or Inline 6 that are known for their torque.

Per wikipedia the highest specific torque for a natural aspirated gasoline production car engine in the world (including truck engines) was the last BMW M3 that came with a naturally aspirated inline 6 at 86 lb-ft/liter. And I don't recall BMW M3s getting 26/37 mpg.

I realize it isn't fair to compare a modded engine (although the core engine is untouched) to factory engines, but that still very impressive any way you slice it.

So when somebody asks you what's so special about Skyactiv. That's what you can tell them. Power of a gas engine, torque and fuel efficiency almost like a diesel, and no turbo funny business. Just the way I like it. All motor baby!
 

·
Registered
Joined
·
1,998 Posts
this sounds like a zoom zoom boom moment eminent.
There was an automotive journalist that once said "I had an epiphany that engines invariably run their sweetest right before they explode".

That's because combustion efficiency is great for power, and the engine will sound awesome, but it's stressing the components until that tiny crack/flaw in the piston, connecting rod or pin, or crankshaft that's been there since day one starts growing at a rapid clip until it fails in a dramatic display of fracture mechanics and metal fatigue in action.

So you have to ask yourself, "How big are the initial microscopic cracks in your engine's components?" Are you feeling lucky? LoL
 

·
Registered
Joined
·
560 Posts
I am so friggin confused...did the original OVtune thread get deleted from when we voted @solar365? I can't find it! I would be very happy with 220HP! I Would definitely add an SRI vs CAI if tuning though.
 

·
Registered
Joined
·
66 Posts
Easily worth the money for the tune if it gets those gains and is safe. I want to see and hear that Supercharged Skyactiv-G that they have. Would love to the see the dyno of that.
 

·
Registered
Joined
·
1,998 Posts
All,
-I have no updates. I provided my contact info via PM on the 5th of December and haven't heard back. OVTunings last log in to the site was this morning for the first time since the 5th, so hopefully they have my info and will be shipping the kit soon.
-The thread for that is here: http://forum.mazda6club.com/mazda6-atenza/333241-mazda-6-2-5l-skyactiv-ecu-tune-review-request.html
Go to www.ovtuned.com to see the dyno plots they do have, one of which is the MZR 2.5 with the esupercharger. The skyactiv would only be stronger especially in the lower rpms.
 
61 - 80 of 239 Posts
Top