For: 4-stroke superjet - benefits to intake and exhaust upgrades without upgraded ecu map?

[segmentlime]

I have been looking at the Riva Stage 1 upgrades for the 4-stroke Superjet.

I have a Kommander intake grate.

1)Any performance benefits to installing just the Riva intake and exhaust upgrade kits without getting the ECU map flashed with RIVA Stage 1 using Map Tuner? Any numbers for such with 93 pump gas?

2) What would adding the Stage 1 map flash add to performance with 93 pump gas?

3) Any other (maybe more reasonably priced) options for getting a stage one type ECU map installed?

4) Riva has an exhaust kit whereby you drill out some mesh on the intake manifold opening and then add a billet hose connector piece. Do you think same performance benefits could be achieved (and save some money) by simply drilling out the mesh and skipping the billet piece?

5) The marketing material for the Solas Yamaha 144mm Concord Impeller claims improved performance at both the low and high ends. This seems somehow counter intuitive. Do you think this is the case? (And if so, how do figure they manage this because it seems like impeller configuration changes usually improve one end with a sacrifice at the other?) Do you think there would be value in the impeller change alone?

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[Big Kahuna]

Different strokes

Rodney Dangerfield working his new Yamaha Superjet, last weekend. I rode it a couple sessions and I have some initial thoughts. Since purchasing, Rodney's done a few tweaks to his ski: Rideplate Grate Exhaust mod Pole spring RIVA rear sponsons Throttle return spring removal These pics were...

www.x-h2o.com

Read through this.

 

[segmentlime]

Thank you for the thread link. I have read it carefully and follow that one. That is a great thread but doesn’t specifically cover the questions I raised. It seems they did the intake and exhaust engine upgrades at the same time as the ECU flash; the flash is by far the single most expensive part of this, and so my questions were about potential value, if any, of the other changes without the new map?

Also, it seems they used the Riva kit for the intake ribbon delete, and I have that size hole saw so was asking if just skipping the billet connector and just cutting out the mesh could work?

As well, I guess I do not understand how any impeller change could improve both the low end and the high end all else same, so i was hoping someone could enlighten me on this?

 

[kevbo]

If it turned more rpm it could make more thrust and go faster. Our two stroke engines with a tuned pipe cant turn more rpm without changing the pipes length so there is more compromise. The new Superjet cant be made much more powerful unless there was a simple factory governor that could be bypassed. That is unless some kind of supercharger was installed. The aftermarket needs to wring every cent out of their customers just to survive. Thats why there is so much simple bolt on crap available.

 

[segmentlime]

If it turned more rpm it could make more thrust and go faster. Our two stroke engines with a tuned pipe cant turn more rpm without changing the pipes length so there is more compromise. The new Superjet cant be made much more powerful unless there was a simple factory governor that could be bypassed. That is unless some kind of supercharger was installed. The aftermarket needs to wring every cent out of their customers just to survive. Thats why there is so much simple bolt on crap available.

yes, more rpm would mean more thrust and go faster, but would this not be the case for any impellers not designed to optimize the low end?

Sorry to keep asking the same question, but what I still do not get is how changing the shape of an impeller alone can yield improvements to both the top and bottom ends?

 

[kevbo]

If the impeller was a better shape it could provide more thrust for a given amount of torque at a certain rpm. This could provide better acceleration and a higher top speed. I have recorded higher thrust levels at low speeds with all concordes and swirl type large hub impellers but never higher top speeds. Over the years most of the improvement has been low speed pump priming. That was an area where old straight pitch impellers suffered the most while they still went fast. We tend to go faster with a little more pitch because standup pumps run above the waterline so the inlet water is less dense at high speeds.

 

[motobehrens]

The ECU flash and the impeller are where you'll see your gains, and should be your first engine related purchases. The intake and exhaust hardware aren't necessary. Your Kommander grate is about 1mph faster on top end than the more aggressive grates.

 

[bored&stroked]

If its a MAP based engine and not MAF, then doing the mods without tuning could hurt the engine from running lean.
On sportbikes, even just an exhaust will cause issues these days without tuning. They already run them at the edge of lean for emissions.