New Aritcle - thoughts on a Mercury Racing 3.4-liter R-series engine

[John S]

Did the 300XS have warranty? I'd assume so, because there are a ton of big brand bass boats with them. Which is odd, because I think they shared the same Motorola electrics. Can't remember if my gen 1 200XS had warranty. The XS ROS was such a a great motor, shame it didn't sell well.

Of all the "Race" motors, I wonder what the big seller was. I'd assume the 2.5 Promax and 300 XS?

[David]

The 300XS had a warranty. The Gen 2 200XS was sold until around 2015? For me the 200XS was a great Promax replacement. It would not have been enough for someone used to a 280 or 260.

[PanRonnie]

You can still have a lot of fun with 200Hp engines


And still get a free mouthwash

[PanRonnie]

The LS2 is a close match to the 3liter 150 in bore, stroke, valves sizes
https://gmauthority.com/blog/gm/gm-engines/ls2/

since you would run a vented proppelor low end torque is not really needed so you could cam up to maximum availeble horsepower
so if the 6 liter LS3 with slightly bigger valves makes can get to 541 horsepower would 270 out of the 3 liter block be possible?

[Chaz]

There is no reason that you can't make 100 hp / Liter and still be reliable .. with not much work.

Keep in mind that Mercury sells motors to anyone who has the money and wty's them. Even if the guy can break an anvil with a rubber mallet. Of course they come out of the box half asleep ...

It's like the old days of hot rodding. You either do it yourself (no aftermarket) or buy motors from the mother ship that put out 50% of what they should be capable of.

[PanRonnie]

Megasquirt just put out a new affordable ecu for it
https://www.diyautotune.com/product/...mini-ecu-only/

[Chaz]

I saw that. Looks good .... cept for :
No peak + hold injectors
Only 4 ignition drivers
No wiring harness
02 is $200.00 more

It would be just right for the 150 hp 3.0L

[PanRonnie]

The 150 uses high impendance injectors and runs 2 ignition outputs doing dis coils
You could change that to COP ignition or wasted COP
The engine does not have a camshaft and does injection in two stroke mode (every 360 dgr an injection)
You could add a cam sensor and let the fuel puddle on the intake valve as long as possible
With the 24-2 tooth pattern it's almost plug and play

[David]

Yes, 200HP on the right boat can be a lot of fun.

Does one necessarily lose low end torque when tuning for high rpm power? That used to be a nostrum. Can variable valve timing and lift (and other complexities) overcome this?

[Tcatrett]

I have a 150 pro xs. I'm just waiting for the backordered 162 gears for the sport master. Gunna give y'all some stock results soon.

[PanRonnie]

Yes, 200HP on the right boat can be a lot of fun.

Does one necessarily lose low end torque when tuning for high rpm power? That used to be a nostrum. Can variable valve timing and lift (and other complexities) overcome this?

Yes but it adds complexity and cost

[PanRonnie]

I have a 150 pro xs. I'm just waiting for the backordered 162 gears for the sport master. Gunna give y'all some stock results soon.

You could contact jarod about doing an article about it
He was trying to squeze as much speed out of his allison with a 150

[Greg G]

Lightweight cowl from the APX would not be an option, they are full carbon and extremely expensive.

You start talking about remapping ECU's, you steer away from your point of "off the shelf parts". Everything else takes time and money and I will ask you again- who is lined up to buy a 500+ lb V6 that would be maybe 100hp less than a 300R?

Just catching up on this thread so apologies Petey. You make a very valid point on using the lightweight carbon cowl from the APX 200.

The MSRP on it from Mercury is $9,460, while the 225 V6 fishin cowl is $2,997.

Your point on ECU remapping is not valid. An OEM can remap an ECU for close to nothing as they have all the programming logic completed and in house. Motor mounts and 4.6L Sporty are already available so no design time needed at all which is why I loosely use the label "off the shelf".

Someone would have to hang the 3.4 V6 225 R motor on a scale to truly know what it weighed "all in" with fluids and no one has ever done that so far. All S+F and Greg T knows for a fact is that the V8 300 R weighs 561 pounds and is taller.

[Petey]

Your point on ECU remapping is not valid. An OEM can remap an ECU for close to nothing as they have all the programming logic completed and in house. Motor mounts and 4.6L Sporty are already available so no design time needed at all which is why I loosely use the label "off the shelf".

So you're saying there is already a "225R" ECU map out there and the only thing they would have to do is flash it onto boxes? No development or testing needed?

[PanRonnie]

So you're saying there is already a "225R" ECU map out there and the only thing they would have to do is flash it onto boxes? No development or testing needed?

That would be the easy part, having different hardware parts on an assembly line makes more of a challenge
225 hp is 225hp you could make the ignition a bit more agressive but other than that it's not rocket science
Finally got hold of a seperate mid to test my engines or hopefully a test mule