Cutting the exhaust on an optimax?

[skywalker26v]

Can you cut the exhaust on a 2006 250xs optimax? Or will it screw up the computer? I want this baby to scream like a cut out 2.5, but dont know if it can be done. Anybody know?

[Stitch King]

While cutting the can on a 3.0 L EFi was a no brainer because they ran rich anyhow, the Optimax is a different story.

The Optimax uses a Motorola 555 processor to run the fuel, air and spark system. What that means is that it's much "smarter" than the old 16 bit processors the old EFI system had. As a result the fuel curve is much more accurate and much closer (read LEAN) to a Stochiometric mix than before. That's why they get better mileage :)

Unless someone can supply data on pyro readings before and after cutting, if it were mine I would proceed with caution.

Whether or not the computer will convulse, I'm not sure. The computer is operating in an open loop. Basically a preset bunch of values. If it frees up a bunch of air flow and the MAP sees that who knows if it will freak. All depends on the range that's programmed.

Ken

AKA....know it all

[Jay Smith]

I would feel OK with altering most any Mercury engine BUT an Opti....

They (OPTI's) are VERY finicy and I would'nt suggest it...

[espen]

In theory the great thing of the optimax system is that it makes a stratifyed charge around the spark plug that have a rich mixture. The outside can be just air . The advantage could be that it can run lean total mixtures without detonations or overheating .
We all need some more info on tuning the optis , would be great if you would try to cut the exhaust and post the results. But maybe you would ruin your engine who knows.....

[WILDMAN]

While cutting the can on a 3.0 L EFi was a no brainer because they ran rich anyhow, the Optimax is a different story.

The Optimax uses a Motorola 555 processor to run the fuel, air and spark system. What that means is that it's much "smarter" than the old 16 bit processors the old EFI system had. As a result the fuel curve is much more accurate and much closer (read LEAN) to a Stochiometric mix than before. That's why they get better mileage :)

Unless someone can supply data on pyro readings before and after cutting, if it were mine I would proceed with caution.

Whether or not the computer will convulse, I'm not sure. The computer is operating in an open loop. Basically a preset bunch of values. If it frees up a bunch of air flow and the MAF sees that who knows if it will freak. All depends on the range that's programmed.

Ken

AKA....know it all

Talk english boy! Us dumb old guys ain't got ANY idea what you is sayin!

[Skatin]

If it frees up a bunch of air flow and the MAF sees that who knows if it will freak. All depends on the range that's programmed.

Does the Opti have a MAF sensor????? I wasn't aware of that..

[Euroski]

I don't think the 300xs has a MAF. I think it's all calculated by the ECU with data from the TPS and MAP sensor(s)? Will need to dig out the 300xs manual...

[Skatin]

I wouldn't think the outboard environment would be very good for a MAF. To dirty and wet with oil and water etc...

[espen]

In my oppinnion the reason for better fuel milage in optimax are :
1:Fuel injected after the exhaust port are closed.
2:Better atomisation and faster burning mixture because of the pre mix of fuel and air from the Compressed air /fuel mix tru the air injector.
3:Lean burning capability because of stratifyed rich mixture close to spark plug.
4:Individual cylinder fuel and spark advance .

They need the hefty ECU to controll the 12 air and fuel injectors and 6 ignition coils, sequential ! That meens at a certain rotation crank angle the ecu fires these outputs , at an other trottle angle or rpm the angle where the outputs are fired are changed.

No MAF or Manifold Air Flow sensor on this engine , its just a speed /density system that uses manifold pressure and rpm to find the spot on the look up maps where to collect the opening times of injectors.

On a opti engine you would need something to measure the fuel mixture inside the combustion. Maybe you will get a reading at high rpm WOT from pyros on a opti.

[props4u2]

As espen stated, there is no maf sensor on the opti's. The 555 ECU has not been used on the opti's since 2000. I can't remember what the current PCU is called but it is far advanced technology over the 555.


Lee

[skywalker26v]

Thanks for all the responses guys. The bad ass in me wants to hear that scream of a twisted up 2 stroke, but the conservative side in me doesnt want to lean out and melt down my new engine!:D I guess if I wanted to hear it scream, i shoulda kept the old V8 Johnson on it, but unfortunatly it made my scream out loud more than it did! haha But you know, Im glad I finally asked, because I've always wondered. I felt like it would be a great disscussion starter in the forum too. P.S I think it is still a 555 processor because I have an old copy of powerboat from 05, and they still talk about the 555

[Laker]

Can the fuel pressure be adjusted on an Opti?

[espen]

I think its always possible to crush the fuel pressure regulator to increase the fuel pressure or change it to a adjustible one . I think have heard of programmable fuel pressure regulators to ....changing the fuel pressure to adjust to a changed volumetric efficency. There was a Italian company that offered raised rpm limmits to 200xs optimax engines , they had the ecu cracked and got 20-30 hp more at the top adjusting the fuel and rpm limmit .
Just had a look at MAD efi and Wayne Taylor are making a 20" mid with rear exhaust for the 300xs :-)

[Stinky]

An 06 XS uses PCM03 ECU. The 08's use the PCM07 ECU.

Fuel pressure is set by a tracker valve to be a value above the air pressure.
Trust me, you DO NOT want to start messing with the pressures unless you have the ablity to re-cal the entire ECU.

XS's use a map sensor. Will not adjust properly to a cut can.

Hope this helps.

:cool:

[Stinky]

There was a Italian company that offered raised rpm limmits to 200xs optimax engines , they had the ecu cracked and got 20-30 hp more at the top adjusting the fuel and rpm limmit .
:-)

Without changing something else on the engine (cut heads, porting) they did not gain 20 to 30 horse by adjusting anything in the ECU.:rolleyes:

:cool:

[blkmtrfan]

Without changing something else on the engine (cut heads, porting) they did not gain 20 to 30 horse by adjusting anything in the ECU.:rolleyes:

:cool:

Were they able to get it to spin up higher?

In other words will the 2.5 opti spin up if the rev limiter was removed or does it hit a "RPM wall" that can't be passed with the opti induction system?



What about constucting a "dual induction" system.

Conventional EFI in the front half that you only use at higher RPM and then the opti system on the back half for low and mid RPM???

[Stinky]

A 2.5L opti will spin higher than a 3.0L.

But it has nothing to do with the injection system.

The "RPM wall" in direct injected emissions motors is the depth of the combustion bowl and the inability to scavange the deep bowl at high RPM.

:cool:

[blkmtrfan]

Thanks for the reply


The "RPM wall" in direct injected emissions motors is the depth of the combustion bowl and the inability to scavange the deep bowl at high RPM.

So the "dual" system won't work either ;)

[Stinky]

Thanks for the reply



So the "dual" system won't work either ;)

Not for a true emissions motor. If, however, you were building a high HP, high RPM motor, with a good fuel economy in cruise, it would have advantages, but would not pass emmisions.

Oh, and Yamaha has a patent on the duel injection concept.:rolleyes:

:cool:

[blkmtrfan]

Thanks again :)


Oh, and Yamaha has a patent on the duel injection concept.:rolleyes:

Have they built one, or are they just trying to keep everyone else from building one?

[Stinky]

Thanks again :)



Have they built one, or are they just trying to keep everyone else from building one?

There is really no reason for anyone to build one. The gains on an emissions compliant motor is not worth the expence, and there's no reason to build a non-compliant engine.

Its one of those patents that has no reason. (at this time)

:cool:

[Fish]

thank you stinky, great info.

[espen]

<TABLE class=testopiccolo cellSpacing=4 cellPadding=4 width="100%"><TBODY><TR vAlign=top><TD>The "RPM wall" in direct injected emissions motors is the depth of the combustion bowl and the inability to scavange the deep bowl at high RPM.
Thanks stinky ,great info , thats why the air pressure is increased on the 200xs to make it work at higher rpms ?
Espen
Below from the company www.turmax.com (http://www.turmax.com):

MERCURY 200 XS


On request of some racing teams we developed the file for Mercury 200XS with the very good results.
By raising RPM quantity only in RPM limiter TURMAX has tested the 200XS engine on the engine test system and has recorded 198 Hp at 6800 original RPM and 179Hp at 7200 RPM.
By re-programming the original ECU, without operating on the engine, TURMAX has succeeded in getting 210Hp from 6700 RPM up to 7200 RPM!
The highest increase (+30Hp) was obtained at 7200 RPM.
Smart Craft and the connection with Mercury tester diagnosis remain unchanged and no runaway speed is signalled (for further details please get in touch with TURMAX at <?XML:NAMESPACE PREFIX = SKYPE /><SKYPE:SPAN onmouseup="javascript:skype_tb_imgOnOff(this,1,'0',false,16,'');return skype_tb_stopEvents();" class=skype_tb_injection oncontextmenu="javascript:skype_tb_SwitchDrop(this,'0','sms=0');return skype_tb_stopEvents();" onmousedown="javascript:skype_tb_imgOnOff(this,2,'0',false,16,'');return skype_tb_stopEvents();" id=softomate_highlight_0 onmouseover="javascript:skype_tb_imgOnOff(this,1,'0',false,16,'');" title="Call this phone number in Italy with Skype: +39024403428" onclick="javascript:doRunCMD('call','0',null,0);return skype_tb_stopEvents();" onmouseout="javascript:skype_tb_imgOnOff(this,0,'0',false,16,'');" durex="414" context="+39 02 4403428" IamRTL="0"><SKYPE:SPAN class=skype_tb_imgA id=skype_tb_droppart_0 title="This is a Italy phone number. The country code cannot be changed." style="BACKGROUND-IMAGE: url(C:\DOCUME~1\Espen\LOKALE~1\Temp\__SkypeIEToolbar_Cache\1f2ea9f97276da0aaf6cc66e3f75b0e7\static\i nactive_a.compat.stat.w16.gif)"><SKYPE:SPAN class=skype_tb_imgFlag id=skype_tb_img_f0 style="BACKGROUND-IMAGE: url(C:\DOCUME~1\Espen\LOKALE~1\Temp\__SkypeIEToolbar_Cache\1f2ea9f97276da0aaf6cc66e3f75b0e7\static\f amfamfam/IT.gif)"></SKYPE:SPAN></SKYPE:SPAN><SKYPE:SPAN class=skype_tb_imgS_stat id=skype_tb_img_s0></SKYPE:SPAN><SKYPE:SPAN class=skype_tb_injectionIn id=skype_tb_text0><SKYPE:SPAN class=skype_tb_innerText id=skype_tb_innerText0>+39 02 4403428</SKYPE:SPAN></SKYPE:SPAN><SKYPE:SPAN class=skype_tb_imgR id=skype_tb_img_r0></SKYPE:SPAN></SKYPE:SPAN> or by e-mail)
Price is 1,500.00 €
<TABLE class=testopiccolo width="100%" border=1><TBODY><TR vAlign=top><TD>Price is 1500,00 €</TD><TD></TD></TR></TBODY></TABLE></TD><TD>http://www.turmax.com/db/foto/nautica/me$cons$mecons_200xs.jpg (http://www.turmax.com/sito_ing/marine_racing_dinamica.php?id=9#)</TD></TR></TBODY></TABLE>

[blkmtrfan]

Interesting website espen

http://www.turmax.com/

Thanks for the link

They show ECU mods for pretty much all of the Mercury Optimax products as well as the Verados, but the only one they listed the actual HP increase for was the 200xs. I would be real curious to see the results for the other motors....

Stinky, do you know anything about these guy and their work?

[Stinky]

<TABLE class=testopiccolo cellSpacing=4 cellPadding=4 width="100%"><TBODY><TR vAlign=top><TD>The "RPM wall" in direct injected emissions motors is the depth of the combustion bowl and the inability to scavange the deep bowl at high RPM.
Thanks stinky ,great info , thats why the air pressure is increased on the 200xs to make it work at higher rpms ?
Espen
Below from the company www.turmax.com (http://www.turmax.com):

MERCURY 200 XS


On request of some racing teams we developed the file for Mercury 200XS with the very good results.
By raising RPM quantity only in RPM limiter TURMAX has tested the 200XS engine on the engine test system and has recorded 198 Hp at 6800 original RPM and 179Hp at 7200 RPM.
By re-programming the original ECU, without operating on the engine, TURMAX has succeeded in getting 210Hp from 6700 RPM up to 7200 RPM!
The highest increase (+30Hp) was obtained at 7200 RPM.
Smart Craft and the connection with Mercury tester diagnosis remain unchanged and no runaway speed is signalled (for further details please get in touch with TURMAX at <?XML:NAMESPACE PREFIX = SKYPE /><SKYPE:SPAN onmouseup="javascript:skype_tb_imgOnOff(this,1,'0',false,16,'');return skype_tb_stopEvents();" class=skype_tb_injection oncontextmenu="javascript:skype_tb_SwitchDrop(this,'0','sms=0');return skype_tb_stopEvents();" onmousedown="javascript:skype_tb_imgOnOff(this,2,'0',false,16,'');return skype_tb_stopEvents();" id=softomate_highlight_0 onmouseover="javascript:skype_tb_imgOnOff(this,1,'0',false,16,'');" title="Call this phone number in Italy with Skype: +39024403428" onclick="javascript:doRunCMD('call','0',null,0);return skype_tb_stopEvents();" onmouseout="javascript:skype_tb_imgOnOff(this,0,'0',false,16,'');" durex="414" context="+39 02 4403428" IamRTL="0"><SKYPE:SPAN class=skype_tb_imgA id=skype_tb_droppart_0 title="This is a Italy phone number. The country code cannot be changed." style="BACKGROUND-IMAGE: url(C:\DOCUME~1\Espen\LOKALE~1\Temp\__SkypeIEToolbar_Cache\1f2ea9f97276da0aaf6cc66e3f75b0e7\static\i nactive_a.compat.stat.w16.gif)"><SKYPE:SPAN class=skype_tb_imgFlag id=skype_tb_img_f0 style="BACKGROUND-IMAGE: url(C:\DOCUME~1\Espen\LOKALE~1\Temp\__SkypeIEToolbar_Cache\1f2ea9f97276da0aaf6cc66e3f75b0e7\static\f amfamfam/IT.gif)"></SKYPE:SPAN></SKYPE:SPAN><SKYPE:SPAN class=skype_tb_imgS_stat id=skype_tb_img_s0></SKYPE:SPAN><SKYPE:SPAN class=skype_tb_injectionIn id=skype_tb_text0><SKYPE:SPAN class=skype_tb_innerText id=skype_tb_innerText0>+39 02 4403428</SKYPE:SPAN></SKYPE:SPAN><SKYPE:SPAN class=skype_tb_imgR id=skype_tb_img_r0></SKYPE:SPAN></SKYPE:SPAN> or by e-mail)
Price is 1,500.00 €
<TABLE class=testopiccolo width="100%" border=1><TBODY><TR vAlign=top><TD>Price is 1500,00 €</TD><TD></TD></TR></TBODY></TABLE></TD><TD>http://www.turmax.com/db/foto/nautica/me$cons$mecons_200xs.jpg (http://www.turmax.com/sito_ing/marine_racing_dinamica.php?id=9#)</TD></TR></TBODY></TABLE>

The 200XS ran stock air and fuel pressures. (80 air, 90 fuel)

3.0L XS motors went to 95 air, 110 fuel for better penetration of the plume. This helps in all areas of calibration, from idle stability to high rpm missfire. It is not an aid to scavanging. (removal of the burnt gasses from combustion)

You CAN NOT gain 20 to 30 HP from calibration alone on a 200XS.

[blkmtrfan]

You CAN NOT gain 20 to 30 HP from calibration alone on a 200XS.


Did you already try that :D

[Stinky]

Did you already try that :D

Many, many times.;)

:cool:

[Stitch King]

Sorry for the confusion....I corrected my original post typo from MAF to MAP. Have thought about trying to add a MAF though....

Can anyone confirm which chip they are using in the ECU? All of the stuff I've looked into on these told me Motorola 555.

[Stitch King]

Here's what's needed to program Motorola 555-565 Chips. Because we don't have a standard OBDII port like cars (that I know of) you gotta go in through the BDM.

Wherever it says "car" in the lit substitute "outboard motor".

http://www.autosvs.com/product/?p=136

Last I looked the whole kit with computer interface was about $7000.00

[Stinky]

Can anyone confirm which chip they are using in the ECU? All of the stuff I've looked into on these told me Motorola 555.

An 06 250XS has the Motorola PCM03 ECU.

[Stitch King]

Stinky,

Are you refering to the PCM (complete module assembly) Model number or the Processor (chip) inside of it? I've been refering to the chip.

Everything I see says the processor (chip) is 555.

Here's another BDM programer link. Go almost to the bottom of the list and you will see the 2 entrys for Mercury. One is for the I/O's and the other looks like it's the outboards. They say the Motorola ECU has a 555 chip in it too.

http://shop.diagt.com/product_info.php?products_id=447

[Stinky]

Stinky,

Are you refering to the PCM (complete module assembly) Model number or the Processor (chip) inside of it? I've been refering to the chip.


http://shop.diagt.com/product_info.php?products_id=447


I was refering to the PCM.:rolleyes:

:cool: