X'es and R's

[Wild Bill]

How much more performance does a 300R have over a 300X? From what I have read here they seem to have more performance

[river rocket]

The X performed great. It was an awesome motor that still holds it own today. The XS replaced it, but didn't make it to the level of the X in performance. The R, in many applications, meets and exceeds the performance of the X. Looking at it from the lens of boats built today, I would take an R over an X on modern performance boats (few made today and most are bass/fishing/flats boats for smaller boats or offshore fishing and big cats/tunnels). The R is a heavier motor, has a lower limiter, no 15" aftermarket option, and larger diameter gear case. In some applications it may not be the best fit.

[mikesufka]

I never did it, but didn’t the DCR kit put the “XS” back to “X” territory for performance ?

I ran both 300 Promax & 300XS on the same boat with same set up and props ( Spectre 30 ) - noticed zero difference in performance - was quite disappointed.

Ran 300X on my Skater 28 - the X is a great motor !

MDS

[river rocket]

Yes, the DBR kit made an XS nearly an X and R. It also made an XS an X in oil consumption and gas as well. LOL.

It was also a good way to toast a compressor if you didn't put your own mental limiter in place. After testing one, I wouldn't run an XS without DBR.

The below video makes that comparison with the R. Funny thing is, I had an X when I bought the Allison. If I would have been big into testing at that time, I could have all 4 motors on one boat at one point. It would have made this video complete.

https://youtu.be/gzDuYAF7ihU?si=JTeqelL0DjT2AYMX

[Wild Bill]

Well, I have a 300X on my 21 Daytona, Obsession. I was thinking of a repower and would be disappointed if I put a 300R on and the only thing I would get is an empty wallet. I know the 400R should work because they weigh the same as the blower motors Randy puts on the Liberators. What I want is the ability to blast through the hop zone on glass water and take three people and a cooler over 100mph any place and time. And run 115-120 mph by myself. I don't think a 300R would do it.

[Speed Jr.]

Well, I have a 300X on my 21 Daytona, Obsession. I was thinking of a repower and would be disappointed if I put a 300R on and the only thing I would get is an empty wallet. I know the 400R should work because they weigh the same as the blower motors Randy puts on the Liberators. What I want is the ability to blast through the hop zone on glass water and take three people and a cooler over 100mph any place and time. And run 115-120 mph by myself. I don't think a 300R would do it.

Your 21 probably won't be the best candidate for either motor, especially the 400r since it has such low free board. Having owned both a 300R and 400R on Liberators, the 300R is faster in all situations with the exception of a long stretch for top end speed. The torque of the V8 really shines with heavy loads and low-mid range. Although the R would surely be better than what you have, any 330hp motor would struggle to give you exactly what your demands are. Most those who didn't see performance gains when switching to the 300R are those who just bolted one on at the same engine height with the same prop as the prior motor. They new motors need hydraulic jackplates and completely different props. I picked up 8 mph on top and probably 10mph when full load on the 21 when switching to the 300r. I think the 400R L 6 is a great motor, but not worth the extra weight it comes with. It's a slug at low speeds compared to the 300R. I can't say enough good things about the 300r, which also runs on 87 octane. It's a fantastic platform.

Jr.

[river rocket]

I agree with Larry and will add that you need at least a 450R to do what you want. Great deals on 450’s right now. For either the 450 or the 400 you will need to re-rig the boat. It’s around $4-9k depending on if you do power steering with DTS stuff. The 300r on the other hand drops right in for the most part.

[Z06man]

i DID A dbr hood and the tune did not get close to a 300X

I never did it, but didn’t the DCR kit put the “XS” back to “X” territory for performance ?

I ran both 300 Promax & 300XS on the same boat with same set up and props ( Spectre 30 ) - noticed zero difference in performance - was quite disappointed.

Ran 300X on my Skater 28 - the X is a great motor !

MDS

[Z06man]

I have done a couple of 300X to 300R there is some gains on a 32 Skater from 300x to 300R gained 3 mph and would carry a load better. Brads triple 300x to 300R gained about the same. And they are doing it on 87 octane and a lot less fuel.The new 400 v-10 might be a better option 87 octane 6600 RPM They are 5.5 inches taller but they work well.They will kill a non tuned old l6 400R.

[mikesufka]

I have done a couple of 300X to 300R there is some gains on a 32 Skater from 300x to 300R gained 3 mph and would carry a load better. Brads triple 300x to 300R gained about the same. And they are doing it on 87 octane and a lot less fuel.The new 400 v-10 might be a better option 87 octane 6600 RPM They are 5.5 inches taller but they work well.They will kill a non tuned old l6 400R.

Can't wait to try mine

MDS

[wagoetzmann]

Who tunes l6 400R's now......have one I would like to get tuned.....

[PaulR]

This is a little off topic, but I just bought a new 300 ProXS with a TM case for my South Bay 24ft tritoon sport, I replaced a 200 I4 that ran 37mph. Just curious what kind of gains I should expect from you guys that know a lot about these motors and what the difference is between the 300R and the 300 ProXS?

[Wild Bill]

I would guess 45-50

[mikej]

We have tested the same exact boat (30 Spectre) except for different years with pairs of 250XS, 300X, 300XS with DBR stage 2 and 300R's. The 300R is a torque monster and I am a believer in the Mercury 4 stroke program on larger boats. I would take the 300R over any 2 stroke Mercury made on a twin engine cat application.

[Wild Bill]

I was kind of worried about the weight too. I know my boat has four inches less freeboard, but it has 14.5 inches set back now and I would guess with a 400R it would need to be about 8 inches. Whatever Randy would recommend. That would have to help some. Why can't they make a 400 V8 that runs on premium? I don't think that would be difficult.