Stock 2016 AR192 top speed runs

[haknslash]

Did a few top speed runs today while the boat is still stock. I've sourced a SVHO intercooler so just waiting on the guy to get back with me. Boat was with just me (230 lbs) + gear.

First run was with the bimini stowed and just after launching the boat, so no heat soak on that run.
Second run was a little later in the day with bimini deployed and with heat soak.
Third run was at the end of the day heading down the river with the current. Top speed was nice even with bimini deployed.

All in all not bad but it will be nice once upgraded IC is in.

 

[Olin]

Interested in any gain you may get with the new IC. Be sure and post. Please post before and after rpms and speeds.

 

[Shannon]

Cant wait to see your results.. I hope some day I will locate one these SVHO intercoolers.. Look on ebay and green hulk daily... I hope it all works out for you!

 

[WildBillF1]

Those are pretty good numbers. Since I got the boat in June, the fastest I've seen is 43 mph. Air temps have ranged between 107* and 118*. Water temp on the river has been 76* and water temp on the lake has been 84*.

I'm anxious to see how much improvement you get after you install the new intercooler. I'm still shopping for one too.

 

[Olin]

That's about right. We see the upper 40's to 50ish initially. If we stay at full throttle the speed drops down to about 42 and the rpms drop to 6800 sometimes as low as 6600. The engines ECT (engine coolant temperature) sensor will report a reading of 250*F and if you shoot the head with a temp gun it'll read anywhere from 250*F to 280*F. Very hot for an engine that uses water as a cooling medium. However, the IAT (intake air temp) sensor reports a value of 130*F to 135*F. Cool enough to make decent horse power. You can open the engine hatch about half way and anchor it in place and remove the air inlet hose from the air box and let it lay off to one side and it'll regain everything. The ECT still shows a value of 250*F and the IAT still shows a value of 130*F. Nothing changes there but your getting a denser initial charge with no pressure drop across a filter. It'll run at WOT rpms and stay there. The down side, they won't pass a leak down test. The engines aren't clearanced to run at the temp they're reaching. RIVA RACING sells a cooling upgrade kit and thermostat deletes. I have no experience with them. I'm trying to run into someone that has installed them on a boat and is scanning the electronic package to see the improvement if any. The thermostats are rated at about 143*F and should be fully open at 150*F I would think. If the flow through the engine is high enough you shouldn't see 250*F values from the ECT even if the water temp is 100*F. There is quite a difference between 100*F and 143*F. Enough of a difference to have enough exchange to keep the engine operating temp at or just above the thermostat rating if the flow rate is high enough to dissipate heat as quickly as it builds. Mercruiser and Volvo Sterndrives have thermostats rated at 165*F and at WOT rpms (4400-5200) they're either running at temp or about 10* higher. Same water, same day, same time. Heavier boats and bigger engines. 212*F is the magic number here, without a pressurized system. If there is someone out there that has installed the RIVA RACING cooling kit on a boat and has verified the performance using a laptop, tablet or other please post.

 

[texmo02]

Olin, your analysis makes it seem like the engine cooling is deficient, not the intercooler. Do you, or anyone else, know what the engine uses to decide to limit rpms? Those who have added a dedicated intercooler cooling line have as a side effect improved the engine cooling - I wonder which part is helping more.

 

[Olin]

ECU tracks engine rpms, boost, oil pressure, engine temp, knock. Any one can trigger rpm reduction. Knock will usually get some timing retard and extra fuel thrown in. I can look into it more. I know the engine temp is also tracked as a gradient, so the rise time or rate is tracked.
That's correct about the cooling. As long as the engine stays at regulated temp it'll run. Once it leaves regulated temp it'll start slowing. The hotter it gets the more noticeable the loss of rpm and speed. I haven't seen the ECT readings go above 250*F myself and I've ran WOT for twenty miles. These have electronic throttle bodies and I haven't seen any throttle reduction occur when this "slowing" is going on.
I've done some specified tests for Yamaha, that's how I know about the engine hatch being raised and locked into position. Taking the intake tube loose at the air filter housing I discovered on my own. Nets about another 150 rpm, average. And that's regardless of the position of the engine hatch, up or down. I've also created a fuel cooler using a five gallon bucket and about 25 feet of 3/8" copper tube and using ice as the cooling medium. Haven't hooked it up to a boat yet but we ran water through using a water hose and the exit temp was in the upper thirties Fahrenheit. Have done this before for a customer that raced a ski. Really changed the character of the ski. It was his first win in racing. But we weren't having any engine temp problems either. Eager to try it on a 192 anyway. Like to see what some really cold fuel will do for these hot engines.
I noticed that the RIVA cooling kit has another cooling line coming off the cover for the screen located on the pump. Would have to bore a hole in the boat to plumb this line through. Absolutely doable. Would look a bit peculiar. But if it worked that'd be great. Trying to figure out where they plumb to on the engine or if they create another passage for extra water.
Well, have to hit the hay. Tomorrow brings another day in the recreational marine industry. Safe boating.

 

[haknslash]

I'd be careful with those RIVA cooling mods. It seems cooling is finicky and you can get gas in oil if you go overboard with cooling mods. Bunch of stuff about it on the greenhulk forums regarding cooling mods and GIO.

The cooling line you see coming off the strainer block is a dedicated water line for the intercooler. Check out the sx192 mod thread and you'll see some run a dedicated line to their IC.

 

[DBamaC]

I just sent payment for my SVHO intercooler. Might be able to get it installed and to the lake for testing before the end of the season!

 

[Olin]

I'd be careful with those RIVA cooling mods. It seems cooling is finicky and you can get gas in oil if you go overboard with cooling mods. Bunch of stuff about it on the greenhulk forums regarding cooling mods and GIO.

The cooling line you see coming off the strainer block is a dedicated water line for the intercooler. Check out the sx192 mod thread and you'll see some run a dedicated line to their IC.

That's interesting. Sounds like they're running so cold they aren't coming up to temp. Wonder if it has to do with RIVA's thermostat delete and their cooling kit where they are replacing the water jacket anode with a fitting? Can't do that on an EPA engine. Gotta have temperature, just not way above boiling. I'm sure they met spec at regulated temperature. Everyone else does.