Getting my 1st 300R V8 this week.

**mjw930** · 07-24-2018, 05:55 PM

Originally Posted by kct11

How much extra can you really get with a tune on a n.a. motor with out making other changes. I would imagine it's like any other tuner for a gas automobile motor. Like 15-20 on a 400 hp motor. Big tuning gains happen with forced induction.

and let’s not forget your warranty is toast.

**engineermike** · 07-24-2018, 05:59 PM

Originally Posted by Radiant

I read somewhere that the case is designed to run really high and have less drag than a 3L sportmaster when properly set up. Seems the boat is already 2 mph faster than the 300xs setup from the initial report. The 300 Verado boats slowed down with the bigger cases cause they are being pushed through the water. That is not the case here. Only thing here is the need to run a bigger prop because of the bigger case...

Correct. The water inlet on the hdsm is lower and further back than the 3.0 sm. This allows for higher running, which offsets the larger bullet. The larger case is to fit bigger gears for longevity and durability reasons, which we the consumer like as well.

https://www.screamandfly.com/attachm...1&d=1503497432

http://www.mercuryracing.com/wp-cont...ster-Front.jpg

**Rigaud** · 07-24-2018, 06:26 PM

Originally Posted by kct11

How much extra can you really get with a tune on a n.a. motor with out making other changes. I would imagine it's like any other tuner for a gas automobile motor. Like 15-20 on a 400 hp motor. Big tuning gains happen with forced induction.

Like with N/A car engines usually you can get 7-10% more on most engines with a good tune. Some less depending on the engine block, heads, etc... design.
At 300 H.P. stock and the torque this engine produces already, it`s impressive as is. 4-strokes have come a long way, just like 2-strokes when I remember 115 or 140HP was a big deal.

**kct11** · 07-24-2018, 08:05 PM

Originally Posted by Rigaud

Like with N/A car engines usually you can get 7-10% more on most engines with a good tune. Some less depending on the engine block, heads, etc... design.
At 300 H.P. stock and the torque this engine produces already, it`s impressive as is. 4-strokes have come a long way, just like 2-strokes when I remember 115 or 140HP was a big deal.

From what I remember looking at tunes for a gas na motor, say on a Corvette, was boarder line waste of money. If you wanted to change parameters and get small gains that's what they were good for. Last time I seen a hot rod show it was full exaust kit, fresh air kit, dyno tune for like gain of 20.
I would say my 2017 yz450f is pretty dialed in now by Yamaha to make very good power. I can buy a tuner for it, but you don't seen any hp gains with them. You buy the tuner to change the power delivery and that's about it. Oh, you can check run time too.
The people that are banking on aftermarket making hp for their 300r in stock form will have to find additional reasons to validate the investment.

**engineermike** · 07-24-2018, 09:35 PM

Originally Posted by engineermike

Correct. The water inlet on the hdsm is lower and further back than the 3.0 sm.

Note that wildman ran the 300r 2-3/8" above the pad. What do the 3.0 sm's run? 1 to 1-1/2 above?

**Chaz** · 07-25-2018, 12:04 AM

Well I have read how people are going to turn up the boost .. on an engine that is naturally asperated .

That this is going to be a 10 cylinder , V-12 Pppfftttt .. why stop there ..

They would be foolish to not offer a 1.62:1 gear set . But then , when they wrote the prop book that said that a 24" wheel was the most efficient . If so , then they were idiots for not following interdepartmental findings , add one more tooth to the pinion and offer a 1.48:1 cog and get the wheel down where its happy .

Tunes ? Anybody try sending a 2014 and newer box in to have the limiter raised ?
Ahhh .. sorry , no can do . Talk to someone who's been to .. no talk to a 2018 -2019 tech seminar instructor and see if he speaks of any new firewalls put in place

Torque , they put the meat of the power where everybody rides around at anyway. Touch the gas a little , feels like ya get a lot , and ya do !
Only problem with flat torque curves is they fall off abruptly on top when they run out of breath .
Putting that new 300 on a light boat with a 1.75 gear and then going out and looking for top end numbers reminds me of when I put a 706 cubic inch motor in a light weight rear engine dragster . It would have went just as fast towing the motorhome and trailer down the track … food for thought .

**powerabout** · 07-25-2018, 01:52 AM

Do any of the 4s Mercs have a eprom chip with the map on it or have they tightened it up and buried it in the ecu like BRP?
Is it a Motorola or their own?

**Rigaud** · 07-25-2018, 06:01 AM

Originally Posted by kct11

From what I remember looking at tunes for a gas na motor, say on a Corvette, was boarder line waste of money. If you wanted to change parameters and get small gains that's what they were good for. Last time I seen a hot rod show it was full exaust kit, fresh air kit, dyno tune for like gain of 20.
I would say my 2017 yz450f is pretty dialed in now by Yamaha to make very good power. I can buy a tuner for it, but you don't seen any hp gains with them. You buy the tuner to change the power delivery and that's about it. Oh, you can check run time too.
The people that are banking on aftermarket making hp for their 300r in stock form will have to find additional reasons to validate the investment.

Yup.
Small gains on N/A motors.
Power band distribution via a tune is the difference. My Audi A3 has the R32 motor (3.2L VR6 24v) Stock 250hp, ECU flashed tuned 265hp. DSG transmission can be flash tuned as well but not done. It's very different but where talking road vehicles with a tune versus outboards on boats with far more resistance to forward motion.

**powerabout** · 07-25-2018, 06:31 AM

with the vertical car engine as an outboard there are a few compromises re inlet and exhaust plumbing, not to mention one gear

**mjw930** · 07-25-2018, 07:10 AM

Originally Posted by powerabout

with the vertical car engine as an outboard there are a few compromises re inlet and exhaust plumbing, not to mention one gear

The new 4 strokes are not vertical car engines, they are a clean sheet design intended for outboard application before the first cast was made. Outboard design by nature place intake and exhaust constraints due to packaging so I’m not sure what point you are trying to make aside from stating the obvious.

**skydog** · 07-25-2018, 07:41 AM

Yup never tuned any na motors but every forced induction is done right out of the gate with meth HUGE GAINS!! 400R on the way and the ecu to Whipple before i even start it lol!!

**AZMIDLYF** · 07-25-2018, 10:07 AM

I'd have to think that a cam change is a bit more user friendly than port grinding as far as power band timing. Electronics will be the sticking point surely.