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SJRwake

So I have some technical questions for those master mechanics out there. I understand a great deal of how internal combustion engines work and know most of the facts about the PCM 409 and 450 engines. My question is a bit more in depth though as I seek to understand the difference in these two engines better. WHat is the actual different in them. I have been told that the 450 is just the 409 on a tune. If that is true, is it just a ECM tuner that have on it or is there actual mechanical differences. Is the VVT change in the 450 and are different injectors used? What are the actual differences in the 2 engines and whats to stop someone from turning a 409 into a 450 if its just tuning? Also for both engines with them having high compression ratios(but not force injection) would it be better to run higher octane to avoid predetination vs the recommended base 87?

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ahopkinsVTX

This isn’t meant to sound sarcastic, but I’d run the recommended octane. 

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Infinitysurf

I have a 2014 PCM ZR409, been an awesome engine with zero issues. As far as the differences between the 2 engine, I am not positive on all the details but know the 450 shares the same base 6.0L platform as the 409, pretty sure the 450 has a hotter cam and perhaps some other small mechanical differences (could you find out by comparing the service manual parts breakdown?). I have read that tunes are not possible for these engines due to some kind of programming lock placed by PCM, I know some people tried re-tuning the Raptor platform since they had/have a base engine that is rated 400/440 and everything I read (on the TigeOwners forum) indicated that trying to tune the Raptor 400 into a 440 was not successful. I only know what I have ready on this subject tho so nothing above is reliable info

When I initially got my boat, I tried the high test 93 ethenol free for a summer and then switched to 87/89 ethenol free after learning that 93 does not necessarily mean its better for or creates more power than 87... regardless, for me there was zero noticeable difference on power (the timing on these engines is not manually adjustable) seems like these 2 engine platforms are not tuned to really benefit from the higher octane, PCM just tunes them for the 87 from the jump (personally I appreciate that savings at the pump). Since then I have used mostly 87 ethenol free since I have a station very close to me at a great price and have had no problems whatsoever during last 5yrs.  I have heard that perhaps the higher octane is slightly more fuel efficient....and I would guess that there is some torque increase from the higher octane but if the "extra" power is literally not noticeable, then why spend more to fill it up?

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shawndoggy

The pcm 450 is the same as the 409, save for a hot cam and a tune.  While PCM generally tunes their motors to work fine on 87, I've been advised by pcm directly that high octane is recommended for the 450 (91 is apparently OK if that's all you can get, even though the manual says 93).

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SJRwake
19 hours ago, Infinitysurf said:

I have a 2014 PCM ZR409, been an awesome engine with zero issues. As far as the differences between the 2 engine, I am not positive on all the details but know the 450 shares the same base 6.0L platform as the 409, pretty sure the 450 has a hotter cam and perhaps some other small mechanical differences (could you find out by comparing the service manual parts breakdown?). I have read that tunes are not possible for these engines due to some kind of programming lock placed by PCM, I know some people tried re-tuning the Raptor platform since they had/have a base engine that is rated 400/440 and everything I read (on the TigeOwners forum) indicated that trying to tune the Raptor 400 into a 440 was not successful. I only know what I have ready on this subject tho so nothing above is reliable info

When I initially got my boat, I tried the high test 93 ethenol free for a summer and then switched to 87/89 ethenol free after learning that 93 does not necessarily mean its better for or creates more power than 87... regardless, for me there was zero noticeable difference on power (the timing on these engines is not manually adjustable) seems like these 2 engine platforms are not tuned to really benefit from the higher octane, PCM just tunes them for the 87 from the jump (personally I appreciate that savings at the pump). Since then I have used mostly 87 ethenol free since I have a station very close to me at a great price and have had no problems whatsoever during last 5yrs.  I have heard that perhaps the higher octane is slightly more fuel efficient....and I would guess that there is some torque increase from the higher octane but if the "extra" power is literally not noticeable, then why spend more to fill it up?

these are great points you make, so a higher octane actually burns slower and is designed to reduce the possibiliy of knocking due to its slower and less sensative combustion ratio. it takes a higher compression to actually explode and that eliminated the possibility of pre detination which causes knocking. so the engine does have sensors on it that should identify if an explosion is off timing and then will pull the timing back on the cams to adjust for the explosion to absorb some of the shock and eliminate knocking. i talked to a PCM technician and tho the 409 is tuned for 87 it will protect your engine over time on higher octane. 

The technician also told me that PCM does lock there ECMs and will not allow aftermarket tuning. only thing you could do is buy a 450 ECM all together and plug it into a 409 engine.

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