2020 ar190 IATs and other questions

[JohnJameson]

-Bought new in May
-30 Hours now
-Do all my own maintenance with service manual
-First boat, I'm coming from an LS3
- Immediately regretted not going boosted
- Will upgrade in a few years but for now...
Ribbon delete with Riva spacer is done, looking at doing an intake but my concern is how hot the engine bay gets.

I'm not so worried about more airflow, I want to get the IATs down. At least with any other engines high intake temps and it will start to pull timing. Is that the case here or am I not getting something? After running wot I can barely put my hand in the bay, it can't be helping that little engine sucking in all that hot air.

I'm pretty decent at mild fabrication on cars and I don't plan on spending a ton of money because I understand any gains are going to be unexciting at best, however I'd like to try. Anyone ever tried pulling air from somewhere else?

I was thinking maybe through the compartment where the existing airbox is, towards the front, and creating some type of duct high under the bench seat on the port side. It stays dry there and would get "colder" air. Then putting heat reflective tape on the portion in the engine compartment leading to the throttle body.

One concern was all the tubing might restrict flow, but i think with an aftermarket filter, the flow combined with colder air might offset the added length of pipe? What do you all think?

-Other question is about the lack of general engine information that is displayed. Does yamaha have a proprietary plug that allows for diagnostic information as well as temperatures? OBD2 ports in cars are standardized and you can plug in a Bluetooth reader, download an app and display it on your phone or tablet. Does that exist or is that fantasy land in boating?

I have seen all of the tuners that cost $400, is there a cheaper option to just see how hot the air or oil is?

Sorry for the lengthy post, thanks everyone!

 

[2kwik4u]

SO.....it's a different world in a boat. It takes VERY large gains in engine power to notice seat of the pants increases. Basically, the juice is rarely worth the squeeze here. Even extensively modified supercharged boats are only seeing 6-10mph increases on the top end. I think @SamCF can speak to that. He has the fastest boat on the site that I know of. I think top speed is around 62mph currently, and a I've seen other reports from factory spec'd 195's in the 50-52mph range. The loading on a boat is so much different than that of a car, it's hard to explain.

To directly answer some questions;

You can certainly reduce the IAT some by moving the inlet outside the engine bay, however the temp difference is minimal. It might 120-130deg in the engine compartment, and 80-90deg in ambient air. The engine bay of your boat is significantly cooler than that of your car due to heat rejection to the lake instead of being rejected to the air surrounding the engine. Gains might be minimal at best I suspect. Might gain some consistency from it though. You have a blower in the engine compartment that will reduce the temps in there slightly. I run the blower when pulling a tube, dunno that it helps but it makes me feel better.

There might be some small airflow increases to be made. Many people remove the airbox completely and put a filter right on the throttle body. I've seen a couple DIY piping endeavors as well. I suspect the gains are minimal, and even a 10% increase (highly unlikely) is only ~1.8hp on this engine. It's both small, and already designed remarkably efficient, so gains will be also small. You also need to contend with water intrusion. Not just from lake water entering at speed, but also from wet passengers coming aboard, and torrential rain storms attacking the boat while under way. K&N used to make a "watersock" that would help with this, but likely add as much restriction as the cooler temps took away.

@swatski did some tuning work with a 190 and the MapTunerPro or some device like that. I can't remember all the parameters he could see, but I remember there being more than what is available on the dash. I have significant tuning experience in cars, and have never dove into the boat enough to really know what is available in there and what isn't. I've poked around the engine enough to know there is a temp sensor, and a knock sensor. I suspect there is an EGT sensor in there as well, but haven't confirmed it. With engine temp and knock you can tune pretty significantly, if you could find a way to get a wideband sensor in the exhaust stream (that isn't covered in cooling water), then you could tune AFR and timing pretty decently. Again, not sure what kind of gains there are to be made there though.

If you look back at swatski's posts you can find his review of the MapTunerPro-X, as well as a LOT of data on tuning the impeller pitch for max speed on his SX190 a few years back. His conclusion was that the best part of the MapTuner was the throttle response, and the best all around impeller was the stock one.

YMMV, but if you're looking for speed, a N/A Yamaha with a tower isn't it. Find an older 212SS (twin 1.8s in a towerless 21ft hull), or an SX192 (supercharged 1.8 in a towerless 19ft hull) if you need that speed.

If you want to get some more CONSISTENCY from your N/A 19ft'er, then get an L13 cone, seal the intake tunnel, delete the ribbon, and toss a generic K&N on there. My boat with those mods (minus the K&N) will run a consistent 40mph with or without people/cargo aboard, and will drag a wakeboard from a deep water start with 8 adults and two cooler on board. It's a great all around boat, but it's not fast.

For instance........A good buddy has a 24ft TriToon w/150hp Merc on it that will run 32mph WFO. I can sometimes get into the low 40's on calm days. We raced over about a 5mile stretch on Sunday. He made it to the cove fast enough to get the engine shut off, and was tossing out an anchor when I showed up. I had to slow a few times for wakes that he didn't, and I lose speed in the turns and he doesn't. SO I'm clearly not winning any drag races.

 

[2kwik4u]

@2qwik4u
Thank you so much for the detailed response! That makes a ton of sense about water horsepower vs wheel horsepower.
Do you use all three spacers with your L13?
You have effectively talked me out of the air intake venture. I'm going to start running the blower fan too, never thought of that. Thanks again for taking the time with the reply!

My intent wasn't to talk you out of it. I don't want to squash innovation, or prevent you from modding your boat as you see fit. I just want your expectations to be realistic.

I'm currently experimenting with what spacers I run. Spent the last two seasons with all 3 spacer in. Currently running with the red one removed. Might pull another one before we go out on Sunday and see what it's like. Only pulled about 7500rpm on the drag race with my buddy on Sunday. Wondering if I can "un stuff" the pump a little and get some revs back. Had a decent load as well, and a pretty big head wind Sunday, so top speed was down to ~38-39mph. I can usually get 42mph from her if I can get all 7800revs.

All 3 is a safe bet on the L13. Then tune from there.

My lost revs are a good indication of how the engine performance has changed over the course of the year. Early spring I was able to get ~7,750 revs. Lake temp (which governs engine temp to a small amount) was around 68-70deg, and air temps were similar. Sunday lake temps were 82deg, and air temps were in the low 90's. SO, 20deg swing in air temps, and 12deg swing in coolant temp, and I lost ~200rpm. SO....we might be able to correlate somewhere, roughly, around 100rpm per 10deg IAT change, or so. If you can drop the IAT's 40 deg (say engine bay is 120, and you can get 80deg air in there), then you might pick up ~400rpm. On the big end, this might be 2-3mph. Maybe? Might have some effect on the mid range as well, but that is MUCH harder to quantify.

Another thing to change your understanding of boat engine dynamics......Boats engines are FLOW LIMITED. That means that the top RPM of the engine is typically limited by available power and airflow, NOT the artificial rev limiter in the ECU. This means that so long as you can reach peak RPM, additional flow and power at that RPM will not produce additional speed. There is no variable transmission to increase top speed if more power is attainable. RPM = Speed, fairly linearly (some non-linearity comes from pump flow characteristics, but is outside this discussion), so if you want to go faster at any significant level, then you need to repitch the impeller. The current impeller is shaped to create a good "all around" mix of acceleration, and top speed. It places the peak loading near the top of the rev range for a stock boat. This "single speed" transmission limitation in a boat is part of the problem with getting more speed/power out of the stock setup. The head room is not spectacular, as the system is already pretty closely optimized.

You'll find the same thing in propped boats. You have to repitch to get faster speeds, and then you loose acceleration. Then larger motors have lower gear ratios in the drive units to account for similar pitched props on larger boats. It's really an interesting dynamic, and honeslty quite fascinating how much work has to be put in from the factory to match the power requirements of a hull with the power output and delivery system of a driveline.

Most of swatski's gains in speed came from increasing the limiter, and repitching the impeller. This led to unfavorable results on the low in (bad cavitation, or slow acceleration). He was able to eek out a few more mph (I think he pushed his SX190 into the 50's at one point, I'll have to go back and look), but it became somewhat unusable as a family boat for tubing, skiing, etc. If memory serves me, this is why he settled on the stock impeller with L13 cone and sealed tunnel as the best "all around" impeller setup for a N/A 19ft boat at sea level. I know because of his research, many of the 24ft guys now run the 19ft impellers (they're slightly longer, giving them better "grip" against the water).

 

[JohnJameson]

Man that makes a ton of sense! I never thought about how the water temp is the coolant, and that working with iats is a limiting factor in timing.

Also the transmission correlation is super interesting. Makes me wonder what someone could invent to solve the propeller issue... maybe one that changes shape with rotational force. Very interesting limitation though. There has to be a solution, seems like propeller technology has not advanced in a long time.

I'm going to brainstorm the intake problem though.
Requirements would be:
-Low cost
-Easy install
-Almost no drilling/cutting
-Coldest ambient air
-No more risk in water being taken in

I'm going to start with your recommendations and work from there. I know at least being able to monitor ambient air vs intake air, water temps, barometric pressure, altitude, and the rest will help.

I wonder how do real tuners measure cavitation and ventilation? I'm loving the problem set.

 

[JohnJameson]

What do you mean seal the intake tunnel?

 

[dyfanf]

one other consideration in moving the intake into the passenger compartment is increased noise. I love a good intake growl on my Italian twin motorcycles, but it seems we're all trying to quieten down the noise in our boats! May not be a concern for you. We all have our own goals and desires, and a lot of times just something to tinker on/with is enough to make you happy! Have fun!

 

[2kwik4u]

What do you mean seal the intake tunnel?

Here's what I did. Others have gone much further.

https://jetboaters.net/threads/hero-or-zero-resealed-my-jet-pump.17845/

 

[2kwik4u]

Man that makes a ton of sense! I never thought about how the water temp is the coolant, and that working with iats is a limiting factor in timing.

Also the transmission correlation is super interesting. Makes me wonder what someone could invent to solve the propeller issue... maybe one that changes shape with rotational force. Very interesting limitation though. There has to be a solution, seems like propeller technology has not advanced in a long time.

I'm going to brainstorm the intake problem though.
Requirements would be:
-Low cost
-Easy install
-Almost no drilling/cutting
-Coldest ambient air
-No more risk in water being taken in

I'm going to start with your recommendations and work from there. I know at least being able to monitor ambient air vs intake air, water temps, barometric pressure, altitude, and the rest will help.

I wonder how do real tuners measure cavitation and ventilation? I'm loving the problem set.

I have thought several times of running a water injection setup on the intake. These work exceptionally well on boosted applications to cool the compressed air after a turbo/supercharger, and we have a GIANT reservoir to pull from so the limitation of capacity is removed. I'm unsure how well this would work on the slower velocities and lower pressures in an N/A platform. Not much literature online about using this method in vehicles, much less in boats. It would be an expensive experiment, and requires better instrumentation on the engine to really know if it's a benefit or not.

I think, if I was to plumb a new intake on my AR190, I would pull air from behind the port side rear platform seat. There is already a hole there, it would keep the intake noise somewhat low in the cabin, and it has a low chance of ingesting water while underway, or while raining. Would need a louvered cover to keep casual splashing out from kids and such, but otherwise would be a decent choice. Be very little cutting/drilling to be done, and if you don't like it, it's hidden from sight until you open the engine hatch.

In terms of variable pitch impellers, this is a real possibility. The same tech that is used to control pitch on a turbocharger could be used here. I think there are a couple of barriers to entry from an OEM perspective though. Cost, complexity, and control. For "most" people, it's another one of those systems that is overly complicated and provides only a slight benefit. The cost to implement the system would be extraordinarily high, and there are a ton of pieces/parts/etc to break and malfunction. Large vessels (like cruise ships) use variable pitch props already. They were introduced to allow control at low speeds, and increase efficiency at higher speeds. This compromise was worth millions of dollars in fuel savings, not just 10mph more on a pleasure craft.

I made a comment in another thread, and it would fit here perfectly.....I would love to see someone take a 1.8L N/A engine in something like an SX190, then add some forced induction and a proper fuel management system. I have suspicions that the engines between the SVHO, and the HO are the same engine, and possibly the same internals. I suspect a regular HO 1.8 could take 10-12lbs of boost, and survive just fine. Assuming you had good engine control and monitoring. Something like the Holley standalone EFI system would be nice. It would require a number of custom parts, most notably a new exhaust manifold and fuel injector rail. It's nothing I haven't been a part of building in the past on automotive applications. It would require a pretty significant repitch on the impeller, and I suspect that 155mm pump would be the limiting factor in that setup overall. Yamaha moved to a 160mm pump in the 195's and 275's for a reason, I would wager they found the same limitation in R&D on those boats.

If you really want to go fast on the water, check this build out. He's one fo the guys from Roadkill, and also a HotRod Magazine Editor (or was at some point).

Just don't ask me to take the family out in it.

 

[JohnJameson]

one other consideration in moving the intake into the passenger compartment is increased noise. I love a good intake growl on my Italian twin motorcycles, but it seems we're all trying to quieten down the noise in our boats! May not be a concern for you. We all have our own goals and desires, and a lot of times just something to tinker on/with is enough to make you happy! Have fun!

That's a great point I had not thought of, I am doing sound deadening and that would increase the noise.

 

[JohnJameson]

Internals look to be the same. Why not just slap a supercharger on and re flash?

 

[SamCF]

Internals are not the same. Lower compression pistons, different cam and much larger fuel injectors in the SVHO. 10 psi on a stock NA motor would be a quick boom.

 

[JohnJameson]

Good to know, thanks for the detailed explanation. I know the juice is not worth the squeeze but has anyone done a complete engine swap to something totally different? Just used the hull?

 

[Inthrustwetrust]

My 240 engine compartment gets pretty toasty. There really is very little airflow back there. Blowers on might help. A cheap semi easy thing to try would be just to put a fan under the seat in the storage compartment to try and push some air back and get the engine bay cooler. Might not work but for a couple bucks and a little wiring it wouldn’t be super heart breaking if it did nothing.

I don’t think the gains would be anywhere near worth it, but next level air cooling would be to cut holes with intake fans and pipe air directly back there. This would avoid the worries of getting water in the engine air intakes.

I don’t see variable pitch props coming to pleasure boats. I know little about boat props but a bunch about airplanes props. Variable pitch adds a lot of cost, parts and maintenance, i think it would be a massive challenge if not impossible to get a variable pitch impeller because of how small the impeller is. In airplanes oil pressure changes the pitch, and all the mechanical stuff that controls pitch is in the cone, I don’t think you could get a small enough system in a impeller cone that could handle the stress.