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Mazda MZR 2.5L version - ATTN Dave!

Last Post 12-31-2009 10:05 AM by yo vanilla. 9 Replies.

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sticky667

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west covina

07-20-2009 10:32 AM
So I've been cruising the world wide web and was checking out the new 2009 Mazda 6. It appears to be using a newly designed 2.5L, 89mmx100mm engine. Dave: How similar is this engine to the QR25? Would any of the internals be interchangeable? tks Jeremy

eyesoreracing User is Offline

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12-11-2009 03:50 PM
Um.... no. -Dave

Mark_F

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12-12-2009 04:46 AM
Bore Stroke Ratio a little off? Not that you listed it wrong, just that same with the 2.3L. Longish stroke.

eyesoreracing User is Offline

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12-12-2009 01:23 PM
I guess I'm not understanding what parts the OP thought might be interchangeable. If you aren't hip to the corporate polygamy that determines how things like parts commonality between the Genesis Coupe, EVO, and SRT-4 came to be, then you might assume this kind of interchangability could pop up out of nowhere. After all, large parts of a Mazda6 engine can interchange with a Mercury Mariner or even a Ford Ranger, so anything's possible, right? Turns out, no. The QR25DE and MZR-L5X have no common ancestry, though. Nissan and Mazda don't play together. -Dave

sticky667

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west covina

12-12-2009 02:34 PM
i guess i was a little vague.. being that it's 89mm and 100mm stroke.. if the bore pitch is similar and this is really a stroked 2.3L to 2.5L.. possibly the 2.3L crank can be modified for a less expensive destroking option for the QR.. obviously a few factors like the pitch and bearing sizes are key. and then piston options should be similar and hopefully mazda has a thicker ringland than the thin nissan ones..

smartbomb

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12-12-2009 02:44 PM
Anything would be better than a QR.

boogerboy72 User is Offline

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12-12-2009 04:08 PM
Posted By smartbomb on 12-12-2009 04:44 PM Anything would be better than a QR. i lol'd.

yo vanilla User is Offline

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Appleton, WI

12-30-2009 04:27 PM
Posted By smartbomb on 12-12-2009 04:44 PM Anything would be better than a QR. I don't know, I'm not all that fond of my Mazda6's engine (2.3 version). 'Course I wasn't terribly fond of my old QR's smack you in the face rev limiter either. Mazda wins in fuel mileage though.

eyesoreracing User is Offline

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12-30-2009 07:52 PM
What year is your Mazda6? The early ones (first 2 years) had terrible throttle response and were really weak off the line. Partially the throttle response is due to intentional throttle damping to reduce engine mount windup, but the early cars were really bad because they ran EGR at idle and had too tall a final drive. After the first facelift they were much better. QR25 is still more powerful, though. If you really want to see what a naturally-aspirated MZR should feel like, go test drive an MX-5. They're really a sweet motor when they aren't tuned for 87 octane and front-drive. -Dave

yo vanilla User is Offline

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Appleton, WI

12-31-2009 10:05 AM
It's a 2003, we bought it new then. Don't get me wrong, it gets my wife to work in time and all, and it's been perfectly reliable for all its 65K miles. But yes, the throttle response is a little dim-witted and it's not that smooth through the powerband, nor at idle for that matter.

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