A Message to Riva racing ... hope this post finds you and finds you well

[yam240sx]

Manufacture a Bolt on SC kit for the 1.8 l yamaha engine !! there are so many out there that it could be super profitable $ for you ... get to work ! manufacture , prototype , test , show before and after specs of hp/torque ..sell us the complete kit with all harwdware and hoses and directions !

thanks .

 

[NewBoater]

Our boats are not built for crazy high speeds above 65. And what would we spend 10-15k for a kit to gain 5-10mph? I’m good with 52 for a top speed out of my 360hp. But to each their own!

 

[yam240sx]

lets face it our boats are dead below 4500 ..

 

[2kwik4u]

Our boats are not built for crazy high speeds above 65. And what would we spend 10-15k for a kit to gain 5-10mph? I’m good with 52 for a top speed out of my 360hp. But to each their own!

Supercharger on a 190 would be a big deal. Gonna be $10k to get the hard parts in the engine bay, a tune in the ECM, and a new impeller to handle the power.......But then I could just get a 195

 

[Wake_Dude]

Sheeett.... Quick-spooling-adjustable-boost-water cooled turbo FTW!

 

[yam240sx]

well i guess im behind the times ...https://www.youtube.com/watch?v=JG1s3gIfcNY has anyone installed this or these ?

 

[yam240sx]

only problem is turbos are all high rpm power ... we need low end boost ...SC

 

[Wake_Dude]

only problem is turbos are all high rpm power ... we need low end boost ...SC

Not necessarily. The right sized turbo can start spooling close to 1K rpm and can put out enough boost to for the extra power down low. They can also be computer controlled to bleed boost at higher RPMs. They can literally be tuned any way you like. A properly tuned turbo setup would absolute destroy a supercharger; especially in a 4 banger.

 

[anmut]

I'd be more interested in a bolt on surf pipe. @Cobra Jet Steering LLC when are you making one?!

 

[FSH 210 Sport]

Not necessarily. The right sized turbo can start spooling close to 1K rpm and can put out enough boost to for the extra power down low. They can also be computer controlled to bleed boost at higher RPMs. They can literally be tuned any way you like. A properly tuned turbo setup would absolute destroy a supercharger; especially in a 4 banger.

That is absolutely correct. Diesels make full 35+ psi boost at 2000 rpm. Back in the 70’s F-1 cars were running a stock 1.25 liter BMW block and were making 1200 hp in qualifying trim and 900 in race configuration, and there are no parasitic losses with a turbo charger. It appears the RIVA system has taken care of the heat issue with their water jacketed exhaust piping and oversized water over air CAC.

 

[2kwik4u]

@FSH 210 Sport The parasitic losses is an interesting topic/concept. In reality it takes the particular amount of energy to create a particular amount of boost. A supercharger uses crank hp to create the boost, while a turbo uses the otherwise wasted thermal energy from the exhaust stream to produce boost. The losses are LESS with a turbo, but they are not completely negated. The back pressure created between the exhaust valve and the drive turbine are significant, and rob some level of power.

Also, a typical misnomer is that turbo's are top end power and SC's are low end power. The centrifugal supercharger used on Yamaha engines is of the same design as the "cold side" of a turbo. It's a radial flow compressor. The stock supercharger is driven from a gearset off the crank, while a turbo would be driven by a turbine in the exhaust stream........Anywho....Turbos will, in general, move the power band DOWN the rev range, while superchargers will typically move the power UP the rev range. This has to do with the compressor shaft speed, and how in a supercharger it is linked to crankshaft speed by belt or gear, and a turbocharger shaft speed is NOT linked directly to crankshaft speed. So you can generally get a greater shaft speed earlier in the rev range with a turbo as compared to a supercharger.

This DOES NOT include roots/twin screw style blowers. Those are NOT centrifugal devices, but rather positive displacement pumps and work on a completely different set of principles. Those will typically create a "flatter" boost curve, and will deliver boost from just over idle to redline in a VERY linear fashion as (assuming boost is no bled off otherwise) boost is dictated by the ratio of compressor volume to cylinder volume, and rotation rate mismatching.

I've been forced induction/gearhead for decades. I LOVE this stuff. Took a couple classes in college as electives on EFI control theory, engine design fundamentals, and application based prime mover selection. Super fun stuff

 

[Wake_Dude]

@FSH 210 Sport The parasitic losses is an interesting topic/concept. In reality it takes the particular amount of energy to create a particular amount of boost. A supercharger uses crank hp to create the boost, while a turbo uses the otherwise wasted thermal energy from the exhaust stream to produce boost. The losses are LESS with a turbo, but they are not completely negated. The back pressure created between the exhaust valve and the drive turbine are significant, and rob some level of power.

Also, a typical misnomer is that turbo's are top end power and SC's are low end power. The centrifugal supercharger used on Yamaha engines is of the same design as the "cold side" of a turbo. It's a radial flow compressor. The stock supercharger is driven from a gearset off the crank, while a turbo would be driven by a turbine in the exhaust stream........Anywho....Turbos will, in general, move the power band DOWN the rev range, while superchargers will typically move the power UP the rev range. This has to do with the compressor shaft speed, and how in a supercharger it is linked to crankshaft speed by belt or gear, and a turbocharger shaft speed is NOT linked directly to crankshaft speed. So you can generally get a greater shaft speed earlier in the rev range with a turbo as compared to a supercharger.

This DOES NOT include roots/twin screw style blowers. Those are NOT centrifugal devices, but rather positive displacement pumps and work on a completely different set of principles. Those will typically create a "flatter" boost curve, and will deliver boost from just over idle to redline in a VERY linear fashion as (assuming boost is no bled off otherwise) boost is dictated by the ratio of compressor volume to cylinder volume, and rotation rate mismatching.

I've been forced induction/gearhead for decades. I LOVE this stuff. Took a couple classes in college as electives on EFI control theory, engine design fundamentals, and application based prime mover selection. Super fun stuff

Perfect explanation! Great post!

EDIT: I'd love to rip the supercharger off this engine and run a turbo setup. I can machine/fabricate all of the mechanical parts to exceptional degree; however, EFI tuning is not my strong suit. Someday I'll get around to playing with it. We'll see....

 

[yam240sx]

Perfect explanation! Great post!

EDIT: I'd love to rip the supercharger off this engine and run a turbo setup. I can machine/fabricate all of the mechanical parts to exceptional degree; however, EFI tuning is not my strong suit. Someday I'll get around to playing with it. We'll see....

how much is their kit ? and will it work in our boats ?

 

[FSH 210 Sport]

how much is their kit ? and will it work in our boats ?

A Lot!

 

[1WetBoat]

That turbo kit proved to be cost prohibitive and it was dropped from mass production. Several turbo setups for our motors but they are all pretty much custom. No real drop in kits out there to replace the supercharger.

 

[3 green tornados]

I don’t want to go faster, I want to be able to move more ballast at 10-11 mph. Maybe I just need different impeller?

 

[OrangeTJ]

I don’t want to go faster, I want to be able to move more ballast at 10-11 mph. Maybe I just need different impeller?

Drop in a Cummins and be done with it. Or if you're too lazy for that little shade-tree project, shallower pitched impellers could do the trick, at the cost of higher cruising rpm and lower top speed.