Mercury 409 MPI
 

Mercury's new 409 MPI claims to have a flat plane crank, I'm curious what advantage that gives to a boat. I also see in the pictures what looks like a Holley EFI throttle body...?
I wonder if this means Holley will be able to interact with smartcraft/vessel view stuff.
Wonder if anyone knows more about it?

You might be able to spin it faster. What are the specs for operating max rpm range? I'm not convinced this is a replacement for a big block.

Pretty sure this is their 383 with some more cubes and a new crank.

Industry-Exclusive Flat-Plane Crankshaft

what! Need some more specs if anyone knows

O advantage in this application. Sub 6000 rpm small block chevy. Different noise is all.
Look up / google search flat plane crankshaft v8 advantages.

I rather wish they’d spend 5 $ and a few minutes times to make their sbc exhaust manifold water passages line up to their risers.
:rolleyes

https://www.offshoreonly.com/forums/...ng-issues.html

Performance 400 horsepower 5000-5800 RPM Exotic idle quality Great acceleration Flat-plane crankshaft 150# lighter than 8.1L Speed gains with Bravo One X

Technology ECM 555 SmartCraft 10-pin harness Engine Guardian MPI fuel injection Mechanical throttle & shift

Black-X valves Dry joint iron exhaust Heavy-Duty iron block Forged crank, pistons & rods Shaft-mounted roller valvetrain Full System Fresh Water Cooling Heavy-Duty Eng. oil & PS fluid coolers

Single-point water drain 3-year limited warranty 25W-50 engine oil Long-life coolant Remote oil filter 87 octane fuel

985 pounds. List price $33,425, available next month.

All that For a 400hp 383 ? Nutz !
Damn.
IMHO as always.

Need to get rid of that single point drain system

Another thought; how are they building a motor without CAT's these days? Would be great if they could, but don't see how.

Maybe this is technically a remanufactured engine and not subject to catalyst requirements?

I also noticed that the Quicksilver 8.1 and the 540 Mag stroker are no longer available. Looks like this is your Mercury sourced replacement for big blocks with a warranty.

8.1 has been gone for a while.

Im not super familiar with flat plan crank engines, but I didn’t think they churned out much torque when compared to a similar cross plane crank motor?

and someone repowering a “classic” is going to spend $33k on a 400hp motor that sounds cool, but looks like crap? What are they smoking up there?

I’m confused…

“Rated at 400hp, the 409 MPI Bravo engine is designed to replace non-catalyst 6.1L, 7.4L, 8.1L or 8.2L sterndrive engines in 21- to 31-foot single-engine boats and 28- to 38-foot twin-engine boats built before 2010 (prior to 2008 in California).”

See more here:
https://www.mercurymarine.com/en/us/news/quicksilver-introduces-all-new-409-mpi-bravo-engine-a-repower-option-for-classic-boats/

and especially:
http://goqcrew.com/introducing-the-n...-bravo-engine/

They make more torque because the firing order makes exhaust scavenging more efficient. The only downside is vibration so they are typically used in shorter stroke applications.

More coin than Bam sells their blue 520's for???

Just found this in addition to;
”Typical required modifications include new engine mounts, adjustments to exhaust components and regearing the sterndrive unit to compensate for the 409 MPI engine's higher rpm range.”


https://cimg4.ibsrv.net/gimg/www.off...a9d504cd8.jpeg

Not exactly a drop in replacement, eh?

33k for that or 30k for this.

Gee tough choice,(sic) how many year warranty on the Merc? The LT4 is 3 year.
https://marineenginedepot.com/new-62...-airpac-620-hp

It aint running on Reg with 10:1

How much torque does it make since it is being compared to the 8.1?

it lust 650 at 3600 rpm

The new 409?

Is this a GM small block or the Merc produced piece that replaced it sometime around 2015?

I am sure this is an all in house Mercury block, etc. so that when you have an issue you get to buy parts from Merc for 10 times the cost of normal sbc parts.

I think pretty much all of Merc's current offerings are in-house, likely for that exact reason.

Says needs gears changed in outdrive, therefore not near as much.

would be cool if they mention cubic inch and other particulars. Just mosrky marketing ‘hype ‘ terms at this point.

Not that it matters i guess because way too much money for the end result.

Really seems they hate inboards and i/o’s and wanna just churn out outboards. IMHO

Pretty sure I could build 2 650 hp BBC for the asking price......:D

My guess is it is the MERC produced. Link below says 4.035" bore and 4" stroke. So sort of usual Gen 1 small block combination.
Which the new 2015 up MERC 6.2 seems to be a near identical copy of.
409 Spec Sheet

He had to mean the LT4.
I didn't find any dyno charts or torque specs on the new Quicksilver 409.
Because if the 409 makes 650 lb-ft at 3600??
We definitely need to see that.

In Quicksilver yes.
Mercury still has the 8.2L/502 in³.
Uncertain if they'll sell those for repower or not?

Can you sell just crank? Or the whole bottom end? Price?

Is it any cheaper for flat plane crank engine to be built by mercury or others?

No I quoted from the 620 hp wildman listed

Round table, Genuine question, not sarcastic - typing can look that way, who cares about flat plane stuff in a 400hp sub 6000 rom small lock chevy ? I’ll go one further, 500hp sub 7000rpm small block chevy ? Rpm dependability and power is not an issue of small block chevy’s..

Sure, the new top Corvette engine choices now have flat plane cranks. Why ? At that level, it’s still a ‘just because’ more than really anything.

A 33k 400hp sbc in marine trim is just craziness. What would it be with Cat exhaust ? 40k ? More ? Jeez.

SB,

I'm betting there's more than a handful of guys on OSO that could easily build a N/A BBC that will put out at least double that HP for WAY less than that asking price, or a blower motor that will triple that output pretty easily within that asking price.

As has already been mentioned, it wouldn't be hard to build TWO 400+HP SBCs for that price. Hell, a while back, I found a 383 on CL (didn't buy it) in the 500HP range, fully dressed for street, minus exhaust, with all new parts, including the block, for $7500.

Seems pretty egregious to me.

Thanks. Brad.
(937)545-8991

The exhaust scavenging benefit of a flat plane crank is not trivial. It would be worth 35 ft lbs of torque on the LT5 I recall.

The only trick is keeping the vibes in check.

It’s always been a billet crank proposition. It would be cool and unique if they have tooled up a production one.

In a boat with standard wet non tuned cast iron manifolds ?

Decent article on flat plane cranks for anyone interested in this stuff:

https://www.enginelabs.com/tech-stor...e-crankshafts/

Won't know for a while, not in the parts lookup yet. I can't imagine that it would be cost effective.

Wondering if any connection what so ever to newest Z06 Vette.
Only other thing I have heard domestically with flat plane crank.
Coincidence?
Doubt it, but still wonder...

I was asking about the new 409 since it is being compared to the 8.1 engines. Smaller cubes, higher rpm, less torque I'm sure. Not sure it is a good replacement.