21 Hustler

Mercury Racing typically quotes horsepower at the prop whereas the regular Merc division quotes HP at the crank. Curious the difference between the 3 motors? I think the 350 SCI produces 350HP at the propshaft, so probably more than that at the crank. It is hard to find info on the 400 and 400R if its at the crank or propshaft. Wondering if the 400 might be say, 400 at the crank, 375hp(or less) at the prop therefore not that large of a jump over the 350 SCI.

the 400 seems to have a rev limit of 6800 and the 400r at 7000, that is kind of odd if they are both listed at the same HP, unless that extra 200 RPM brings the propshaft HP up to 400hp on the 400r

The 400ROS on the mercury racing site is clear its 400HP at the prop shaft. I have triple 350 SCI's, other than the ego stickers and some bells and whistles, is there much difference in HP especially between the 350 SCI and the 400? If I am only getting 25 hp per motor extra, is it even worth it?

any info would be great!

Unlimited jd

From what I understand, they make the 50 hp difference but mostly from increased rpm. Also you have to run 93 to see that increase. 87 or 89 will rock the knock sensors and detune a bit.

21 Hustler

since they are both based off the 2.6L Inline 6 block. Would you notice any difference in planing off or better acceleration/power in the 30-40mph range while cruising? Any change in the torque curve around those levels or is the only real difference at the top end, which on a CC with 10+ people on it, the extra 2 MPH is rarely even reached because its just not safe with that many people on board.

Wondering do I upgrade my trip Mercury Racing 350 SCI 2012 model years to new 400r's. If there is no difference until I hit 6800 rpm's, it kinda sounds pointless other than having a warranty.

Am I looking at this incorrectly? I know the 450 is a V8, now that would make a difference in torque, but that isn't in the cards.

Unlimited jd

I have experience with both motors but in completely different hulls so I can’t say for sure. What kind of boat is it? Is it a brand that for resale most will want the 400’s regardless? The 300 v8’s will have more torque and mid range than the current 350’s

21 Hustler

Its a 38ft Statement Center Console. I wouldn't do it for resale though, I am sure people would want 400's over 350's for resale, more for the sticker though. But that doesn't justify spending tons of money upgrading. Boat goes about 70-72 depending on load. If 400's only improve my top end to 74-75 and are the exact same performance wise getting from 0-40mph or 25-50mph then I don't see the point. If it will plane off faster or be noticeable around cruising range, usually cruise at 40 mph, then it might be worth it. Looking like the 400 is the same as the 350 sci until you get to 70mph which is when the extra speed is attained, which in my case is about twice a summer for about 3 mins total does the boat go above 60mph, the passengers just aren't into that.

I see what you mean about the 300 v8 and the 450 v8 making a large difference due to v8 vs I6. Do you happen to have torque graphs for these motors, im curious.

thanks!

Toffen

Hi!

I have a 400R on a Phantom 25. Before I used a 350 Sci. The 350 Sci pulls harder on to plane and has little stronger midrange. But from 4,000 rpms the 400R shift attitude. Really responsive.

My boat ran 81 mph with the 350 Sci with a REV4 25 prop. With the 400R I managed 86 mph with the same prop. Currently 89 mph with a Max 5 prop.

I spoke to people at Nor-Tech and they lost a couple of mph using 400 compared to the 400R.

Cheeers, Toffen

21 Hustler

thanks for the input. If I have a 10-12k lb center console where most of the boating is done with 8-10 people and from 0-45mph. I am looking for better planing off and more midrange power (25mph to 45mph when needed). In that case, it sounds like the 350 SCI is better than the 400r. If I wanted top speed, which I don't, then 400R is the ticket. That is interesting that Nor-Tech had that result, any idea why? Does the 400 produce less power at the prop than the 400r?

From my research, it almost looks like I would be better served with a V8...300's or 450's. The 350 SCI is better for my boating style than a 400R. 450's would be great because its a v8, but a waste of money cause I don't need the top speed.

ALL_IN!

I'm new to center console boating (at least owning one). I've got 3 - 400r's on the new boat. I just can't imagine needing the speed in a cc. If you're running from a storm or have an emergency trip back to dock/ramp, then I get it.

First day we took the boat out, I just about blew everyone out of the boat - I was driving it like my old 42/700 boat! lol <40mph is a much better speed in a cc from an entertainment/enjoyment perspective.

Terry