Results of latest gmtech mods- YAY!!!

[gmtech16450yz]

Haha. I'm easily excited.

I did make a few more changes that had positive results though, I thought I'd pass them along.

In an effort to match the rpm and outputs of both engines closer, instead of re-pitching the port engine a little more aggressively, I decided to open up the nozzle on the starboard side instead. Stock was roughly 85mm, I opened it up to 86.5mm. If the average difference in my engines was =/-300rpm, that 1.5mm change made the difference more like 100rpm. I'm going to take the starboard nozzle to 87mm and most likely leave it there. My boat is a CARB model btw, the port engine runs fine up to a max of right under 7800rpm so far. Yesterday with the starboard nozzle opened to 86.5mm the engines were topping out at +/-7750 and 7650. My goal is to "tune" the nozzle so they both top out at a consistent 7500-8000rpm. I'm close.

Here's the other mod I did to the jet/nozzle area that I think was another positive change. If you look in the turning part of your jet nozzles, you'll see a couple of vertical bumps or ridges on the sides. If you turn the wheel, you can see that the jet stream will hit those bumps and get diverted/obstructed somewhat. I believe what the engineers were trying to do there was to bend the jet stream towards the side more, presumably helping with steering control. The watercrafts don't have those, which also tells me it must have been to aid steering on the boats. My thought was this... Why would you want something that obstructs the jet stream to aid steering after you put the Cobra Jet fins on to drastically improve steering? With the Cobra Jet fins, steering is NOT a problem, so if removing those bumps or ridges lessens steering, so what.

So I removed them! lol. And guess what? The boat loses less speed when turning and corners F'ing hard!!! This 212 now turns so d@mn hard that even after telling us what he was going to do, my son cranked the wheel full lock when going 50mph and my wife ended up in my lap when she slid across the back seat! And she was trying to hold on! I was holding onto the grab handle as hard as I could when he whipped back the other way and I thought I was gonna rip the handle out of the fiberglass! Crazy. Oh and with the intake grate mods I did, this boat HAS NEVER CAVITATED ONCE. You can leave the throttles wide open and do whatever manuevers you want, it will never cavitate or over-rev. Ever.

The other "mod" I did was to swap out the plugs with Iridium's. The stock plugs in the '17 1.8's are NGK 6668 LFR6A's. They're V groove standard nickel plugs, 5k resistors, heat range 6 and a stock gap of .035" or .9mm. Yamaha specs on the gap are .8mm to .9mm. I went with NGK 5468 SILFR6A11's. They're fine wire iridium's with a platinum ground electrode. Still the same 5k resistor and heat range 6, but the stock gap is wider at .043" or 1.1mm. I left the gap stock, knowing that the iridium plugs will be able to fire at a larger gap ok and the coil on plug ignition system in these Yamaha's should have enough overhead to be ok with the higher voltages. The risk on bumping the gap and voltage requirements is that it's harder on the coils, only time will tell me if it matters in this application. I doubt it will be a problem.

I'm not one to say "Oh my god the power is so much stronger and smoother with these plugs!!!". haha. A change like this is VERY hard to notice, even for somebody like me with decades of engine tuning experience. It's more of an attention to details thing. It "should" make a difference, and the difference "should" be positive. Can you feel it? I'm not sure, the engines in these boats run really well anyway. Maybe they're smoother? Maybe they're a little more responsive? Like I said, it's really hard to say definitively with stuff like this. My personal experience says it's a worth while mod to do and you may or may not "feel" a difference.

The other mod I did was to change the cr@p tires on the trailer. That mod IS noticeable and SHOULD be done on any trailer that's actually being used. There's only one reason why Yamaha/Shoreland'r puts the size and type of tires on these trailers... money. The tires are junk and the load range is marginal at best. I think I'll make a new thread for that story though.



In this picture, the "bumps" I'm talking about are the parts that are brightly lit that look like ( ) on the side of the turning part just past the nozzle opening. I ground those off with a porting tool. You could use a round sanding drum like people have used to open the bore of the nozzles too.

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These pictures show after I ground the bumps off the sides...

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[Julian]

I noticed that you loaded the photos to the media album and linked them here....did you know you can drag and drop photos into your post (multiple at a time!)...

Interesting mods....some arrows on the pics pointing to the bumps you are referring to would help me understand what you are talking about there...

 

[Julian]

I'm not one to say "Oh my god the power is so much stronger and smoother with these plugs!!!". haha. A change like this is VERY hard to notice, even for somebody like me with decades of engine tuning experience. It's more of an attention to details thing. It "should" make a difference, and the difference "should" be positive. Can you feel it? I'm not sure, the engines in these boats run really well anyway. Maybe they're smoother? Maybe they're a little more responsive? Like I said, it's really hard to say definitively with stuff like this. My personal experience says it's a worth while mod to do and you may or may not "feel" a difference.

I'm a complete engine tuning moron....can you help me understand how a spark plug can help with the performance of the engine? I would think that if it is sparking and detonating the gasoline, that is the only thing it needs to do. Wouldn't it be really noticeable if it wasn't detonating (fuel in exhaust)? I'm not being a jerk here...just trying to understand how a better/different spark helps.....

 

[gmtech16450yz]

Hi Julian, thanks for the replies!
Yeah ever since photobucket wrecked the internet I've been in a state of mishmash with my pictures! I got a godaddy domain and was going to use it for storing pictures I then link online in forums and whatever, but I got sidetracked and never finished setting it up. So when I started putting pictures on here I just uploaded them to the media section first, not realizing I can drag them into the thread itself. Thanks for giving me the heads up! I really have to go back and set up my photo storage website so I can have a central place to upload to and link to since photobucket will never get ransom money from me.

On the spark plug thing... It's not a jerk or a dumb question at all. You're right, for the most part if the plug is firing and the charge is igniting, it doesn't make a huge difference. That being said, you can effect the combustion with the spark though. In the "olden" days, "indexing" plugs was a common thing for hot rodders to do. It was simply rotating the plug in the head so that the ground electrode wasn't shielding the charge. It was good for a few hp's if you did it right. The iridium to the standard plugs are a similar situation. The standard V groove plugs have a really large ground electrode and positive electrode. They can block the proper ignition of the charge. The iridiums firing area is exposed as much as possible to avoid that. That's just one factor, the gap is another. Changing the plug gap can change the way the engine runs. Too small of a gap can cause a rough idle condition. Too large of a gap can misfire when the mixtures are very lean because the coils can't provide enough voltage to jump the gap. (The voltage needed to jump the gap is way higher when the mixtures get leaner.) A larger gap that the coils and combustion pressures can handle can produce more power because the higher spark voltage does a better job of quickly igniting the mixture. Remember this too, a single cylinder misfire at 8000rpm might not even be felt. A cylinder that just didn't get a "solid" spark to fire the mixture but it wasn't a full misfire won't be felt, but will result in loss of power. Make sense?

 

[Neutron]

What intake grate mod are you refering to?

Are you opening the inside diameter of the actual steering nozzle? And how are you machining it?

 

[gmtech16450yz]

BTW, my next mod... Adjustable pitch!!! I'm determined to figure out how to blend the watercraft outlets that have adjustable pitch to the boats. I'm sure it can be done, there's too much that's the same between the PWC pumps and the boat pumps. I know I can do it, I just have to get time to do it. Right now I'm concentrating on my "other" Yamaha I just bought...

 

[gmtech16450yz]

What intake grate mod are you refering to?

Are you opening the inside diameter of the actual steering nozzle? And how are you machining it?

The intake grate mod I did is in a thread I made with something about "taboo" in the title. I'm not opening the diameter of the steering nozzle at all, it's already really big, maybe even too big compared to the PWC parts. And I'm using porting tools, but you can use whatever you have to grind off the "bumps". A sanding drum on a drill would work.

 

[Neutron]

What did you open to 86.5?
I see the removal of the "bumps"
But not your mod you first referenced

 

[swatski]

@gmtech16450yz This is so much fun reading your posts!!!!
I just found this new thread, gonna be my reading for the night!

You never considered L13 cones, did you.
I must do your intake grate mod.

I'm running new Mapturner X reflashes and having a lot of fun. RIVA's Jesus is writing and "massaging" new tunes for our N/As, we have tested 4 or 5 already.
I'm almost ready to write this up, maybe a couple more tests/outings, should be interesting for some of us.
But cool one point is - we have a tune now that will make my impellers slip in the hole shot! Not a huge amount of cavitation, but definitely is there - due to extra power/torque. Now I just need to harness that!


EDIT: @gmtech16450yz reading you post, I'm surprised you didn't index the plugs, too, LOL.

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[Speedling]

I took the dremel and polished up all the bumps and ridges in my pump pretty early on. I didn't notice much of a difference, but I was more considering a full throttle scenario which it didn't really change.
I wonder though, if less resistance in the pump would increase the mpg of the boat due to less resistance? It wouldn't be huge, but hey, more cruising distance the better!

 

[swatski]

What did you open to 86.5?
I see the removal of the "bumps"
But not your mod you first referenced

Here is the "bump". I must admit - I never noticed it.


I'm pretty sure @gmtech16450yz is boring the venturi nozzle to 86.5mm
That works very well, I've done it before while tuning the L13s. I'm currently running stock, but that is definitely a mod to try - for a killer hole shot.

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[Mainah]

I have an idea to improve performance on the 1.8l NA CARB models that seems right up @gmtech16450yz and @swatski alley. The CAT for the carb models is a tube with a flange around the middle. The tube sits inside a double bell shaped housing that bolts together with the flange in the middle. This sits under a cover at the rear of the engine. From parts diagrams it appears as though the CAT could be removed and the housing put togehter without it.

The first issue with doing this would be the post CAT O2 sensor. Perhaps a simple O2 spacer would resolve CEL or Connext warning message issues but those spacers are known to be hit or miss. Perhaps a simple resistor cap on the O2 wire could solve as well but again those are hit or miss. Better yet custom engine tunes could alleviate the warning and perhaps even work better on CARB engines making use of the pre CAT O2 sensor data. 14:1 is test tube optimal but hot and humid days will affect that so perhaps run a high octane gas and a little rich in the middle of the summer with a custom tune as an example.

The second issue could be flow if the cat tube is removed. Given the skills and knowledge that @gmtech16450yz has already demonstrated my guess is that he could whip up something to solve that in short order.

Improved intake and exhaust, custom fuel maps, higher rev limit, and small pump improvements should equal a noticeable improvement in overall performance.

 

[njmr2fan]

Yes! Definitely what @Mainah said!

 

[swatski]

Improved intake and exhaust, custom fuel maps, higher rev limit, and small pump improvements should equal a noticeable improvement in overall performance.

Very much so!

I don't know much about the 02 sensors and any potential there, the exhaust itself has not been a target of any successful mods making positive difference (not more noise) - that I know of (in 1.8 engines).

(EDIT: reading about "TJ exhaust mod" - I could be wrong about the above)


I have been beyond impressed with the RIVA's support for the Maptuner X team. Well, one man team that is - Jesus Garcia. In his words: “Of course I can make a lot more there… but the point is to keep it really really safe and no stressing for cruising.”
He is really taking the Maptuner experience for me to a whole different level. Part of it could be they are trying to do something for the 1.8 N/A recreational crowd, very under-served/underdeveloped (in comparison to SC). Not easy!

I asked Jesus about installing AFR gauges. His point was - I can do it - but in that NA engine, w/ no extra parts or modified parts like injectors, Cams, etc, there is not much need for it. Rather, we just kind of try things and move on - when he is making incremental changes. One interesting thing he mentioned was that he finds "torque tables" in 2013+ ECUs - that was not there before.

Basically, Jesus is looking at it from the perspective if there is room for improvement while keeping reliability. He likes to patiently move step-by-step, which I really like. They have also offered to get Impros to repitch my props as we move along on optimizing the maps.

I'm still not sure how fast I want to spin (what should be the target max RPM). With no boost to gain, the benefits from spinning faster are very limited, and those engines make most torque/power around 7,800 RPM. So - that seems to be a good number for max RPM (while pushing the rev limiter up - so the limiter does not actually kick in at 7,800).

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[Mainah]

Very much so!

I don't know much about the 02 sensors and any potential there, the exhaust itself has not been a target of any successful mods making positive difference (not more noise) - that I know of (in 1.8 engines).

I have been beyond impressed with the RIVA's support for the Maptuner X team. Well, one man team that is - Jesus Garcia. In his words: “Of course I can make a lot more there… but the point is to keep it really really safe and no stressing for cruising.”
He is really taking the Maptuner experience for me to a whole different level. Part of it could be they are trying to do something for the 1.8 N/A recreational crowd, very under-served/underdeveloped (in comparison to SC). Not easy!

I asked Jesus about installing AFR gauges. His point was - I can do it - but in that NA engine, w/ no extra parts or modified parts like injectors, Cams, etc, there is not much need for it. Rather, we just kind of try things and move on - when he is making incremental changes. One interesting thing he mentioned was that he finds "torque tables" in 2013+ ECUs - that was not there before.

Basically, Jesus is looking at it from the perspective if there is room for improvement while keeping reliability. He likes to patiently move step-by-step, which I really like. They have also offered to get Impros to repitch my props as we move along on optimizing the maps.

I'm still not sure how fast I want to spin (what should be the target max RPM). With no boost to gain, the benefits from spinning faster are very limited, and those engines make most torque/power around 7,800 RPM. So - that seems to be a good number for max RPM (while pushing the rev limiter up - so the limiter does not actually kick in at 7,800).

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My thinking is that more gain can be had with the CARB engines. In my previous head to head testing with one CARB and one non-carb boat it was on a rather cool and low humidity day. I do think the CARB boats bleed off more power and top end as the heat and humidy increases compared to the non-CARB boats. I have a CARB boat. My top end rpm when cool and low humidy is right about 7600. When hot and humid that drops to 7300.

The rare earth metal honeycomb is certainly restricting air flow and holding more heat in the exhaust and the same time. If the O2 sensors are wideband there is a bit that could be done with fuel mappings to improve performance while maintaining fuel economy . Given the other items that are 5v on the computer it is not a stretch to think that the O2 sensors could be wideband. A simple check of the O2 output wire with the engine running at different rpms will tell us for sure. Just adjusting the stock tune on a carb boat with o2 sensors alone might be enough to improve performance.

I am by no means an engine expert and while I could try my suggestions myself my results may be limited by my experience which is why I am just throwing it out there for anyone willing to give it a try. Also down the road when the honeycomb degrades or o2 sensors go bad it will be nice to know if we can find a way to do without $800 cats (also the reason cutting the honeycomb out from the middle of the cat for testing is not a great idea) and $150 post cat O2 sensors.

I would love a faster boat for a fun top speed blast once and a while but I do like knowing that I get slighty better cruising fuel economy.

 

[swatski]

My thinking is that more gain can be had with the CARB engines. In my previous head to head testing with one CARB and one non-carb boat it was on a rather cool and low humidity day. I do think the CARB boats bleed off more power and top end as the heat and humidy increases compared to the non-CARB boats. I have a CARB boat. My top end rpm when cool and low humidy is right about 7600. When hot and humid that drops to 7300.

The rare earth metal honeycomb is certainly restricting air flow and holding more heat in the exhaust and the same time. If the O2 sensors are wideband there is a bit that could be done with fuel mappings to improve performance while maintaining fuel economy . Given the other items that are 5v on the computer it is not a stretch to think that the O2 sensors could be wideband. A simple check of the O2 output wire with the engine running at different rpms will tell us for sure. Just adjusting the stock tune on a carb boat with o2 sensors alone might be enough to improve performance.

I am by no means an engine expert and while I could try my suggestions myself my results may be limited by my experience which is why I am just throwing it out there for anyone willing to give it a try. Also down the road when the honeycomb degrades or o2 sensors go bad it will be nice to know if we can find a way to do without $800 cats (also the reason cutting the honeycomb out from the middle of the cat for testing is not a great idea) and $150 post cat O2 sensors.

I would love a faster boat for a fun top speed blast once and a while but I do like knowing that I get slighty better cruising fuel economy.

Wow, I just looked at it - the first two parts of the CARB exhaust have entirely different architecture!
In terms of mods, I was really thinking of the third part - with water boxes and resonators.

Also, the "TJ exhaust mod" does not apply to boats as we do not seem to have the secondary box they are deleting.

I do plan on testing "cruise fuel consumption" with various tunes vs stock etc., I have little doubt this will be improved.
But I'm not at that point, yet. Still trying to get more power, and then corresponding pump mods to harness it. Gotta bring more ballast for wake surfing!
(if I keep this boat for next year)

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[swatski]

If you look in the turning part of your jet nozzles, you'll see a couple of vertical bumps or ridges on the sides. If you turn the wheel, you can see that the jet stream will hit those bumps and get diverted/obstructed somewhat. I believe what the engineers were trying to do there was to bend the jet stream towards the side more, presumably helping with steering control. The watercrafts don't have those, which also tells me it must have been to aid steering on the boats.

I could be wrong, but I would think those ridges are meant to force "straightening" of the steering nozzles (after a turn) - basically if you where to release the steering wheel in the middle of a turn - the boat will straighten itself up - quicker with the ridges.
I like the idea of shaving those off!
I don't think I will be able to keep up with you, @gmtech16450yz.

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[gmtech16450yz]

Cool discussion and thoughts guys!

On the exhaust mod ideas... Haha that was one of the first things I did was to look at the parts catalog pictures between the CARB models and the rest of them! Yes, the cat looks like it would be super easy to just take out and bolt the two halves back together. There are several reason why I DON'T plan on doing that to this boat. Here they are-

First is I know enough about catalytic converters to know that you can make good power with or without them. My 800+ hp roadster was making that power through STOCK cats. The restriction caused by the cats in this boat application is inconsequential. The physical size of the cats in relation to the amount of exhaust volume going through these engines at WOT/full rpm tells me there's not much to be gained by removing them. And if you simply remove them without "fixing" the exhaust flow, you can cause WAY more power robbing turbulence by removing them. (Which is why "gutting" cats on cars is a stupid idea.)

Second, you can hang out on the back deck while trolling and not gag from the exhaust fumes. The only time I'd actually want to smell the exhaust by removing the cats is if I was running E85. Burning corn smells awesome! (But that's another chapter.)

Third is actually heat, something that was mentioned already. Cat converters create heat in the exhaust. A common misconception is that heat in the exhaust is a bad thing. It's actually not. Having an exhaust system where the exhaust cools off too much before it gets to the tailpipe is a bad thing. Cold air is heavy, hot air is light. Hot air is easier to push out of a pipe than cold air. So having a cat converter heat up the exhaust (or at least keep it hotter) before it has to wind it's way out of the piping is actually a good thing.

The last factor is that although I am ABSOLUTELY not a tree hugging greeniac, deleting cat converters just isn't worth it as far as what it does to the air quality. The possible power advantage is just not worth the price. I actually don't have a problem with the fact that all boats sold in this country will eventually have cat converters. They are a very effective way of cleaning up emissions and modern cat converters do not rob the kind of power that they used to.

A lot of these mod ideas, for me at least, fall under the "slippery slope" category. If I did any mods like removing the cats, I ABSOLUTELY would be monitoring mixtures. And if all I could do is monitor them and not "tune" them (edit the fueling/VE/speed density calibrations), that's like being a cop without a gun. Pointless. For me, for now, I'm not starting into that kind of engine modding because I know the ONLY solution for me would be to ditch the Yamaha engine management system altogether and switch to a Motec or Delphi system. At that point, we're talking about spending at lest $8k to possibly gain a tiny bit of power over what Yamaha has done with the tuning of these engines.

BTW swatski, be careful with that tuning without also monitoring mixtures. I would NOT do any kind of tuning without either monitoring the stock sensors or adding in my own widebands and logging them. Boats run under very different conditions than cars. You can get away with a lot more in an automotive situation than you can in a boat situation. You're trying to optimize efficiency at WOT/7800rpm/full loads. If the mixture is off, those engines are not going to be happy for very long. And even if all he's doing is changing ignition timing, ignition timing most definitely effects mixtures. Just be careful is all I'm saying.

BTW, the reason I didn't try the Lucky 13 cones is simply bang for the buck. At $600+ for the cones, what I did by opening up the nozzle diameter comes very close to the total change the cones would do, and it cost $600 less. Simple as that. If the cones were like $200 or less, I might have "tuned" the pump flow that way. It's basically optimizing vacuum, flow and pressure. You can do it by intake flow changes, impeller pitch changes, cone lengths or nozzle sizing. They're 4 different ways to roughly accomplish the same end results. If one of those changes is free and accomplishes what you need to change to a decent degree compared to another approach, I'm all over that! My intake grate mod and the nozzle size change were both free and resulted in eliminating all cavitation and almost perfectly matching engine rpms through the range. I'll spend the money if I need to, but it's nice to get results for free too!

Also, on the exhaust, I did do another "mod" to it actually. I removed the resonators and shortened the exhaust hoses a few feet in the process. I also removed the silly rubber fingers in the exhaust outlets. WTH are they supposed to prove? lol. They certainly aren't going to "seal" any water from coming in, maybe they're to keep small fish from swimming into the exhaust, idk. Anyway, I didn't remove the resonators for power, I did it because I couldn't hear the exhaust. Now at least it sounds like it has engines.

 

[swatski]

Boats run under very different conditions than cars.

And that is EXACTLY why I'm paying these guys $1.5 for a tuning job! Because that's all they do, is jet skis.

Not sure how much more CAREFUL could I possibly be? LOL.

I don't mean to sound defensive at all! But I also do not want to give the impression I'm being a total yahoo. I decided this was not a DIY job, and those guys (Jesus/RIVA) have basically perfect track record - I am not aware of a single instance of an engine tuned by them for recreational purposes blowing up. At this point I think I have a better chance being stopped by my timing chains breaking than the Maptuner X Stage 1 tunes blowing something up.

I also worked with the Vtech Swedish crew before, I think Jesus is even more conservative.

I'm pretty sure they would happily sell me their RIVA AFR gauges if Jesus felt those were needed, I already asked for it. I would lie if I told you he is doing ignition tables only, or not, this or that. I have no idea what he is doing!

But - he is generally considered one of the best in that industry, along guys like the Dean's team, and I am positive he would not want to risk their reputation by trying to get more out of a N/A rec boat engine than he safely could!

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[swatski]

BTW, the reason I didn't try the Lucky 13 cones is simply bang for the buck. At $600+ for the cones, what I did by opening up the nozzle diameter comes very close to the total change the cones would do, and it cost $600 less. Simple as that. If the cones were like $200 or less, I might have "tuned" the pump flow that way. It's basically optimizing vacuum, flow and pressure. You can do it by intake flow changes, impeller pitch changes, cone lengths or nozzle sizing. They're 4 different ways to roughly accomplish the same end results. If one of those changes is free and accomplishes what you need to change to a decent degree compared to another approach, I'm all over that! My intake grate mod and the nozzle size change were both free and resulted in eliminating all cavitation and almost perfectly matching engine rpms through the range. I'll spend the money if I need to, but it's nice to get results for free too!

The cones are more complicated than that I'm afraid. The twin Yamahas generally have no cavitation issues under normal operation conditions - zero. At least as far as well sealed pumps are concerned that do not suck air. Singles - different story. Wake surfing with a ton of ballast - also different story.

(I'm using cavitation and "ventilation" terms interchangeably here)

The L13 change a lot more than the venturi opening - also change the volume, in an adjustable fashion, and there is no question those can reduce cavitation under certain scenarios such as hard hole shots, running with a ton of ballast, or running on one engine.
Here is what those look like - in relation to the OEM cone - the size difference is not subtle:


There are no good reasons to use L13 to gain just the top speed, at least in my opinion. The fastest skis all use those, but it takes ridiculous amount of time/effort to dial/tune everything in. Great tool if one is into it though!

However, the L13 are awesome in fighting cavitation/ventilation and increasing the pump efficiency. Along boring the the venturi, steering nozzles, and pitch adjustments.

@gmtech16450yz I think in your boat, under current load conditions, I would venture to guess you would not be experiencing much cavitation with the factory setup. These boats generally do not cavitate/ventilate in turns.

In my experience, the cavitation issues become completely apparent once you push it, for example:

1. try a hard hole shot with a single engine boat, especially with an aftermarket impeller pitched for speed etc.
   
2. or a twin loaded with surf ballast

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