Merc 400/400R RPM limitations

[DRAG]

Hi guys. Long time reader of group but first post.

I've flashed my 400 Verados for a higher rev limit and am about to get different props to try to get some more speed. Does anyone know a reasonable rpm limit for these engines? What is the stock rev limit on a 400R?

Thanks.

 

[stoker2001]

the 2.6L 400R has spec Rev limit 6400-7000 from mercury.who did flash,i thought NOBODY was doing that now that Mother Merc sued or threaten too

 

[lake p.a.l.]

I'm FAR from any kind of expert. I believe you want to delete this thread now. I've heard mother M e r c is attempting to sue everyone & anyone associated with those activities, just like Kev said. Good luck

 

[lake p.a.l.]

Hopefully nobody quotes his original questions

 

[n2otoofast4u]

Mercs going to have to deal with it. This is like Ford/Chevy/Dodge saying they are going to sue they aftermarket tuner guys. If you own the fkn motor, and are comfortable with voiding the warranty, then by all rights you tune the fock outta that thing!

 

[HST4ME]

Fuck mercury, all the technology to run these stand alone has been out for a long time, this includes the new motors.

 

[JUSTWANNARACE]

Mercs going to have to deal with it. This is like Ford/Chevy/Dodge saying they are going to sue they aftermarket tuner guys. If you own the fkn motor, and are comfortable with voiding the warranty, then by all rights you tune the fock outta that thing!

There is absolutely nothing Merc can do except for cancel distributorship/factory dealer to anyone that has offered flash. As they can choose who they sale to..

And other than that.. they can do nothing! if I buy the motor IT IS MINE I can do with it as I want!!

 

[JUSTWANNARACE]

I'm FAR from any kind of expert. I believe you want to delete this thread now. I've heard mother M e r c is attempting to sue everyone & anyone associated with those activities, just like Kev said. Good luck

Cant happen!!

Is there a statement in a contract when you buy a motor about that other than "warranty"? If not merc is pissing in the wind!!

 

[HST4ME]

I remember in the early optiflop days when I figured out to stack washers under the tps mounts so the sensor wouldn't flake out. Do what you will.

 

[JUSTWANNARACE]

I remember in the early optiflop days when I figured out to stack washers under the tps mounts so the sensor wouldn't flake out. Do what you will.

Interesting.. was it binding up when tight? Some of the Yamaha atvs we have had to do the same thing with. They would bind the "swing" if tighten to spec. Put a washer behind it and it would work fine.

 

[lake p.a.l.]

There is absolutely nothing Merc can do except for cancel distributorship/factory dealer to anyone that has offered flash. As they can choose who they sale to..

And other than that.. they can do nothing! if I buy the motor IT IS MINE I can do with it as I want!!

Guys I fully understand what you are saying. To each their own. I know there are ways to flash every computer etc. Best of luck to everyone

 

[HST4ME]

Hi guys. Long time reader of group but first post.

I've flashed my 400 Verados for a higher rev limit and am about to get different props to try to get some more speed. Does anyone know a reasonable rpm limit for these engines? What is the stock rev limit on a 400R?

Thanks.

I've seen some turn 7500. The data logging showed that they are at the end of rope there boost efficiency wise. To get much more from them you're going to have to get creative internal parts wise.

 

[Matt Mead]

This is interesting. So would it make 450 hp if spun up to 7500, thus making their 450 offering look redundant? Can't possibly have the smaller cheaper motor make as much power as the bigger one, lol. Funny they got sue happy.

 

[HST4ME]

This is interesting. So would it make 450 hp if spun up to 7500, thus making their 450 offering look redundant? Can't possibly have the smaller cheaper motor make as much power as the bigger one, lol. Funny they got sue happy.

No. The 400s are making some pretty good boost at that point and due to port, cam and blower size/efficiency the party is over. The v8 is a much better motor.

 

[Matt Mead]

Then I don't understand the suing part, because besides voiding the warranty what the heck else is the problem? It's your motor. They don't want the reputation of them popping from too much revs/hot boost left and right? So what, let people modify stuff. Just because there are 9 billion blown Honda K series motors and Mazda rotaries lying around doesn't mean people will stop trying to modify them.

 

[Bullhead bully]

Stock RPM and computers were read by Mercury Racing after this run.
With extended warranties.

I would never screw with these things. They’re too perfect bone stock. If you need more power by a bigger engine.

 

[HST4ME]

Then I don't understand the suing part, because besides voiding the warranty what the heck else is the problem? It's your motor. They don't want the reputation of them popping from too much revs/hot boost left and right? So what, let people modify stuff. Just because there are 9 billion blown Honda K series motors and Mazda rotaries lying around doesn't mean people will stop trying to modify them.

There were guys playing with the 400's on this side of the country on smaller boats. The enthusiasm fizzled out after finding out there isn't much left on the table. The reflashing was popular on the lower hp veradoos that could be bought cheap to get them into the 350 range.

 

[Bullhead bully]

There were guys playing with the 400's on this side of the country on smaller boats. The enthusiasm fizzled out after finding out there isn't much left on the table. The reflashing was popular on the lower hp veradoos that could be bought cheap to get them into the 350 range.

Very true ! The 400R was a good stopping point for the 2.6 liter motor. Good power and stil reliable.

Bottomline the 400R changed performance outboards forever. Put us in the four-stroke performance outboard world. It was only matter of time.

 

[DRAG]

Thanks for the replies guys. I think Merc was slapping shops more because of all the EPA stuff. These 400s are not 400Rs...but its the same engine, lower rpm limit. I have friends that flashed their 350s and saw 8mph on some pretty hefty boats. I know early on when the mid 30 foot cats were trying to become the fastest and that battle was going back and forth, some of them had flashed 400s...it is what it is. Performance boating, you'll have guys trying to "turn stuff up"....kinda goes with the territory. I already have them flashed so was just wondering if anyone had RPM experience first hand before I change props. Thx again.

 

[n2otoofast4u]

Please report back your findings. I’m curious how this shakes out.

 

[Markus]

There is a shop over here that still does the work.

440hp from a 400R, if I remember correctly.

Merc dealers are not allowed to touch any PCM-modified engines. If they do as much as replacing the stickers on the cowling, they can get kicked out.

There is a lot of money on the table given the differences in price. Add to that the warranty expense.

 

[BajaMike]

STOP FLASHING IT. Put it back to factory settings. You said you are new to it. You just fucked up your warranty. You over rev it reduce your engine life. Boating is fun, unless you fuck up your motor. You don’t think Mercury knows what they’re doing? Dumb….dumb.,,,dumb!

 

[HST4ME]

Fuck Mercury, flash the shit out of them.

 

[n2otoofast4u]

STOP FLASHING IT. Put it back to factory settings. You said you are new to it. You just fucked up your warranty. You over rev it reduce your engine life. Boating is fun, unless you fuck up your motor. You don’t think Mercury knows what they’re doing? Dumb….dumb.,,,dumb!

This is about the most LAME comment I have read in a long while.

If everyone went with this theory, who would push things to the next level. If someone has the financial means, and the technology to make it happen, why wouldn't you do it? Stock is boring!

 

[Doc]

Thanks for the replies guys. I think Merc was slapping shops more because of all the EPA stuff. These 400s are not 400Rs...but its the same engine, lower rpm limit. I have friends that flashed their 350s and saw 8mph on some pretty hefty boats. I know early on when the mid 30 foot cats were trying to become the fastest and that battle was going back and forth, some of them had flashed 400s...it is what it is. Performance boating, you'll have guys trying to "turn stuff up"....kinda goes with the territory. I already have them flashed so was just wondering if anyone had RPM experience first hand before I change props. Thx again.

If you have already flashed the computers and don't care then I would look into boost tubes and cowling intake scoops. Those will probably help with the flash more imho.
You have to remember that more rpm past the 7k doesn't mean more power always. The Sc has rpm limits to where you can over spin it and it becomes inefficient, due to heat soak. The tubes and scoops will provide more air for the mid range which you should feel more.

From what the little I have heard and read the 400 was pretty close to being "maxed out" in it's current state and honestly was impressive. You have a straight 6 cylinder supercharged 7k rpm making 400hp on pump, that's no slouch in my eyes.

 

[BajaMike]

This is about the most LAME comment I have read in a long while.

If everyone went with this theory, who would push things to the next level. If someone has the financial means, and the technology to make it happen, why wouldn't you do it? Stock is boring!

If you got money to blow, go ahead, over rev your engine. I know I’m a lame old bastard, thanks for reminding me.

 

[BajaMike]

If you have already flashed the computers and don't care then I would look into boost tubes and cowling intake scoops. Those will probably help with the flash more imho.
You have to remember that more rpm past the 7k doesn't mean more power always. The Sc has rpm limits to where you can over spin it and it becomes inefficient, due to heat soak. The tubes and scoops will provide more air for the mid range which you should feel more.

From what the little I have heard and read the 400 was pretty close to being "maxed out" in it's current state and honestly was impressive. You have a straight 6 cylinder supercharged 7k rpm making 400hp on pump, that's no slouch in my eyes.

Keep it stock, like ”lame” guys do. Because you can run at 7000 rpm, doesn’t mean you should do it all the time.

 

[Doc]

D

Keep it stock, like ”lame” guys do. Because you can run at 7000 rpm, doesn’t mean you should do it all the time.

Guess it depends on how and where you boat.

When we would do dam runs we ran the boats hard. It's impressive how these outboards can run high rpm for long periods of time without issues.

Back to Drag initial question, if he's out of warranty or doesn't care I would get better airflow to the engines to take advantage of the tune. The cowls limit airflow and it's been proven by many already. Throw in some bigger boost tubes and his mid range should increase greatly if it's a quality tune.