30ft motion twin 400r

[AZMIDLYF]

That is why I had previously stated that 32 psi was alarming. Granted, it is inter-cooled but those boost levels will definitely test its durability. Boat motors are run a lot harder and for longer periods than autos. With that said, I am still disappointed in only getting 400hp from it. There was mention of import 4cyl motors earlier making power. You put 30-32 psi through one of them and you are pushing in the 600-800hp range. So what gives?

[Instigator]

That is why I had previously stated that 32 psi was alarming. Granted, it is inter-cooled but those boost levels will definitely test its durability. Boat motors are run a lot harder and for longer periods than autos. With that said, I am still disappointed in only getting 400hp from it. There was mention of import 4cyl motors earlier making power. You put 30-32 psi through one of them and you are pushing in the 600-800hp range. So what gives?

Cars (and bikes) have multi speed transmissions so their motors are not loaded nearly as hard as an O/B w/one gear.
Stick an 800 hp ricer in 5th at a light and see what it does when it turns green.

[Risco]

Absolutely agreed and was going to post similar. From what I see/read, a highly loaded, recreational/automotive application is typically limited to 5 - 7 lbs.

32 on pump gas is unheard of in my world.

I was thinking the 400r were direct injected so i thought you could get away with more boost but there not there efi so i have no idea how unless the compression is super low. But your right its hard to make a motor pull for 1000rpm to 7000

Side note the 5.0 coyote motor on 9psi put down 800rwh stock internals

[mjwalters]

Do we know for a fact that 32 pounds is the normal boost?

[BC Black Max]

Anyone have a service manual for the 400R?
It would interesting so see what the recommended service intervals are on

Valve adjustments, oil changes, timing chain adjustment, de-watering the cooler etc. There is no doubt it is a more complicated power plant then naturally aspirated 2 strokes.

Boost over 15 psi is a lot. 30 plus is tonnes for a supercharger!

[2jz]

32psi is nothing. Very low compression ratio and timing makes it possible to run on pump gas. Other things to consider its a small stock inefficient supercharger that moves very low volume of air CFM. Higher CFM less boost to make same horsepower

[AZMIDLYF]

So what are you hoping to achieve then? You drop compression, retard timing, and then put a half ass SC system on it? Oh, and make it weigh over a 1/4 ton in the process. Still not very convincing.

[mjwalters]

I just read an article over at offshore only, it states nor tech has hung 60 400 horse motors so far this year, and mystic has sold 27

[Toffen]

Hi!

A Vrod 350 Sci has 15 psi at WOT. I have one

its been the best engine I ever had too. I have been through Johnson 3.6 GT Offshore, Promax 300 SVS and 2 x Merc 2.5 EFI SS engines.

Cheeers, Toffen

[Risco]

I just read an article over at offshore only, it states nor tech has hung 60 400 horse motors so far this year, and mystic has sold 27

Thats amazing. Boy do i love mystics

[2jz]

So what are you hoping to achieve then? You drop compression, retard timing, and then put a half ass SC system on it? Oh, and make it weigh over a 1/4 ton in the process. Still not very convincing.

At the end of the day Mercury doesnt care what anyone of us things about what the 400r weights,cost, or how much boost it takes to make 400hp because it wasnt intended for us.To date i know of only one person on this forum buying one even more reason not to care. im sure boat owners with 3-4 400r on thier transom would be singing a different note about how much power they have, how great it feels and wouldnt care what we thought about it also. The fact still remains its 400hp that we all want to have on our boat so learn to live with it and move on because nothing is going to change with the design, or weight of motor.

[joneill]

I think it's great that you are trying them and hope you get the boat where you want it.

[Spectre Powerboats]

Out of curiosity, how is Caldwell doing with his CNC 2.5 blocks?

We are a small percentage of Mercury's market and they are in it to make money. Why not try and get with some of the very talented machine and casting shops out there and manufacture "Race only" motors to get around the EPA's BS. Just a thought and what kind of money do you think it could be done for? I think it would be hard to get it all done for $20K. That is the powerhead, mid and gearcase. JMO. Also, how many guys are going to spend $20k to buy these to make it worth the shop guys time to tool up for it? I would love to see new 280's again. I would be good for a few a year on new Talons.