NEW PRODUCT! RIVA Sea-Doo Exhaust Race Plate

[Deanoo]

NEW PRODUCT! RIVA Sea-Doo Exhaust Race Plate

Has anyone done back to back testing?

Wouldnt this cause more unwanted heat since the plate is not water cooled?

[Green Hulk]

Has anyone done back to back testing?

Wouldnt this cause more unwanted heat since the plate is not water cooled?

These have been around for over a decade, nothing new. They give around 60-80 RPM and they reduce exhaust gas temps.

[ptscon]

Jerry do you know if Riva has EGT monitoring in the works for Maptuner? Curious they would include EGT ports since you basically need a stand alone ECU to make use of those.

[1tommygunner1927]

Has anyone done back to back testing?

Wouldnt this cause more unwanted heat since the plate is not water cooled?

I can measure under seat heat via MoTeC ecu temps. The only instance of increased heat in the hull is after shutting off the engine and everything heat soaks.

[ptscon]

The spacer is between two water cooled parts, head and exhaust manifold, so they act like giant heat sinks to draw heat away. I have not noticed extra heat in the engine bay on my old ski that had the spacer.

[r1goombah]

instead of the exhaust gases burning and making a hard left into the manifold, the spacer ads an extra inch a half so the gases can straighten out before turning, think of it like a throttle body spacer just for the exhaust,

[ptscon]

Wonder why there are no real equal length headers on the market. Too expensive for the gains?

[Green Hulk]

Wonder why there are no real equal length headers on the market. Too expensive for the gains?

Because they would have to be water jacketed which makes them incredibly expensive. The prototypes that were made were always springing leaks causing all sorts of issues.

[1tommygunner1927]

Wonder why there are no real equal length headers on the market. Too expensive for the gains?

A custom water jacketed header would cost $4500+, and would only benefit those running a turbo, not to mention packaging and support for the weight of a turbo. Best suited for maximum efforts in drag racing, not rec skis.

The stock exhaust manifold with a spacer works very well within the confines of a stock hull for supercharges and turbos alike for recreational skis. That said, there is a limit to how much turbo boost one can safety make using the stock exhaust manifold. What that number is I do not know for my sized turbo.......yet.

[Forcefed1986]

A custom water jacketed header would cost $4500+, and would only benefit those running a turbo, not to mention packaging and support for the weight of a turbo. Best suited for maximum efforts in drag racing, not rec skis.

The stock exhaust manifold with a spacer works very well within the confines of a stock hull for supercharges and turbos alike for recreational skis. That said, there is a limit to how much turbo boost one can safety make using the stock exhaust manifold. What that number is I do not know for my sized turbo.......yet.

I wouldn’t worry about the factory Exh manifold in a turbo application. Generally, the restriction is always the exit on the turbo volute and the Exh wheel. Not the manifold or pre turbo piping. Larger runners and collectors just tend to slow velocity and kill spool/response.

FWIW I made 1000ish crank HP on 2” piping (per bank) pre turbo on a 370” V8. That’s 1.8” ID piping per bank on 3 liters per bank. I can’t see the factory manifolds being much of a restriction on a 1.5 liter. At least not for the power/boost most would make.

[1tommygunner1927]

I wouldn’t worry about the factory Exh manifold in a turbo application. Generally, the restriction is always the exit on the turbo volute and the Exh wheel. Not the manifold or pre turbo piping. Larger runners and collectors just tend to slow velocity and kill spool/response.

FWIW I made 1000ish crank HP on 2” piping (per bank) pre turbo on a 370” V8. That’s 1.8” ID piping per bank on 3 liters per bank. I can’t see the factory manifolds being much of a restriction on a 1.5 liter. At least not for the power/boost most would make.

Whatever the "pressure ratio" (PR) is in my turbo, it can be measured and datalogged. I don't know what that number is for my turbo, but I intend to find out. As you probably know, if the PR is too high, bad things can and do happen.

[Chefrey]

I spy-..


Picked one of these up solely for the ease of O2 sensor install. My 2016 rxt260 has a molded in water neck that is in the way where most people tap the exhaust manifold so I couldn't easily install the sensor there. Figured if I'm going to have to pull the manifold either way might as well make it easy and gain a couple rpm!

[Forcefed1986]

Whatever the "pressure ratio" (PR) is in my turbo, it can be measured and datalogged. I don't know what that number is for my turbo, but I intend to find out. As you probably know, if the PR is too high, bad things can and do happen.

Sure, I datalogged exh. back pressure as well.

What I’m saying is even if you changed to a 3” primaries with a giant collector pre turbo, your back pressure wouldn’t change much, since that’s not the bottle neck that dictates exh drive pressure. The turbo is.

As an example, my orig. kit was 2.5” off the manifolds pre-turbo into a T4 1.10 housing and a 75/83 exh wheel. Same engine with 2” piping off each manifold to the turbo flange. Switched to a 1.32 T6 housing with an 87/96 wheel and the overall system back pressure was LOWER and my response time “spool” wasn’t noticeably changed. The higher velocity exh gas allowed me to run a larger turbo without it being a lag monster and made more power per pound. Went from over 2.4:1 BPR to a 1.8 at the same 20lbs.

[1tommygunner1927]

Sure, I datalogged exh. back pressure as well.

What I’m saying is even if you changed to a 3” primaries with a giant collector pre turbo, your back pressure wouldn’t change much, since that’s not the bottle neck that dictates exh drive pressure. The turbo is.

As an example, my orig. kit was 2.5” off the manifolds pre-turbo into a T4 1.10 housing and a 75/83 exh wheel. Same engine with 2” piping off each manifold to the turbo flange. Switched to a 1.32 T6 housing with an 87/96 wheel and the overall system back pressure was LOWER and my response time “spool” wasn’t noticeably changed. The higher velocity exh gas allowed me to run a larger turbo without it being a lag monster and made more power per pound. Went from over 2.4:1 BPR to a 1.8 at the same 20lbs.

Good info, thanks for sharing it. My turbo uses a .64 AR turbine housing but a .85 AR is available, and with a V-band.

[Cagedup]

Because they would have to be water jacketed which makes them incredibly expensive. The prototypes that were made were always springing leaks causing all sorts of issues.

I have always wondered that, but this makes sense.