Stage 2 imuk 8550 vs stage 2 8500

[mikeman]

Hey guys, I am currently running Stage 2 8500 tune with a repitched stock impeller on a 22 rxtx and rear ram intake hitting 82 mph as my best speed so far at roughly 8300 rpm. I was wondering if there would be a noticeable difference if I were to remove my flame arrestor and run the Stage 2 IMUK 8550 tune? Is it worth the hassle? any downsides?

My understanding is it allows full boost to get to the engine and stops the filter from stealing roughly 1 lb of boost.

Other mods: riva catch can, riva sponsons, intake manifold girdle, upgraded intercooler tubes

[troyheb]

I dont know if any one has ever done back to back testing to see if there is any improvement. I have always looked at it this way. If you do it your self it does not cost anything but a couple of hours and it will not hurt anything, so why not.

[mikeman]

I dont know if any one has ever done back to back testing to see if there is any improvement. I have always looked at it this way. If you do it your self it does not cost anything but a couple of hours and it will not hurt anything, so why not.

Some people claim that the hull doesn't have enough air to allow for the increase in air volume unless you are cutting air holes into your hull. So I guess I am wondering if that is correct if I would see a difference without cutting the holes. I also cant help but think that Seadoo has the Flame Arrestor there for a reason.

[troyheb]

You are not increasing airflow by removing it, only allowing all of what is there already, to get into the motor.
Think of like another filter. What do filters do besides filter, they restrict.

[1tommygunner1927]

Hey guys, I am currently running Stage 2 8500 tune with a repitched stock impeller on a 22 rxtx and rear ram intake hitting 82 mph as my best speed so far at roughly 8300 rpm. I was wondering if there would be a noticeable difference if I were to remove my flame arrestor and run the Stage 2 IMUK 8550 tune? Is it worth the hassle? any downsides?

My understanding is it allows full boost to get to the engine and stops the filter from stealing roughly 1 lb of boost.

Other mods: riva catch can, riva sponsons, intake manifold girdle, upgraded intercooler tubes

82 mph @ 8300 rpm with the flame arrestor still in the intake manifold? I'd leave alone and just ride!

[PPDJ]

Hey guys, I am currently running Stage 2 8500 tune with a repitched stock impeller on a 22 rxtx and rear ram intake hitting 82 mph as my best speed so far at roughly 8300 rpm. I was wondering if there would be a noticeable difference if I were to remove my flame arrestor and run the Stage 2 IMUK 8550 tune? Is it worth the hassle? any downsides?

My understanding is it allows full boost to get to the engine and stops the filter from stealing roughly 1 lb of boost.

Other mods: riva catch can, riva sponsons, intake manifold girdle, upgraded intercooler tubes

I have a 2022 RXTX with Stage 2 8500 tune also with stock impeller and am not getting anywhere close to 82 mph. Where are you located and at what sea level. Curious on what your stock impeller was re-pitched to.

[1tommygunner1927]

Some people claim that the hull doesn't have enough air to allow for the increase in air volume unless you are cutting air holes into your hull. So I guess I am wondering if that is correct if I would see a difference without cutting the holes. I also cant help but think that Seadoo has the Flame Arrestor there for a reason.

The flame arrestor provides for a more even airflow to each cylinder. Without it, air flow is not evenly distributed to each cylinder: Stage 2 IMUK tune vs Stage 2 tune.

[mikeman]

I have a 2022 RXTX with Stage 2 8500 tune also with stock impeller and am not getting anywhere close to 82 mph. Where are you located and at what sea level. Curious on what your stock impeller was re-pitched to.

I brought it in to a guy to repitch to get the rpm at the proper range. I'm not sure what numbers it's repitched to, he did it once checked it then tweaked it again and got the ideal range of roughly 8300 at wot. Sea-level of where I got the 82 was 60 meters above sea level (197 ft). This was dash speed not GPS, on my go pro it recorded only 80 mph. This is with seat on. It was a bit humid that day and i was running 91 octane. 195 lb rider. If you haven't repitched the stock impeller then my guess that's whats holding you back. The tune + repitch + air intake should get you there.

[mikeman]

The flame arrestor provides for a more even airflow to each cylinder. Without it, air flow is not evenly distributed to each cylinder: Stage 2 IMUK tune vs Stage 2 tune.

This is good to know, thanks for the info!

[ptscon]

Unless someone posts back to back logs showing RPM gain without the flame arrestor I have a hard time believe that removal improves anything.

Unlike Yamaha, the Sea-Doo flame arrestor has a huge surface area for incoming air to pass through. Plus, as mentioned earlier, it may provide for more even air distribution between cylinders.

[1tommygunner1927]

Unless someone posts back to back logs showing RPM gain without the flame arrestor I have a hard time believe that removal improves anything.

Unlike Yamaha, the Sea-Doo flame arrestor has a huge surface area for incoming air to pass through. Plus, as mentioned earlier, it may provide for more even air distribution between cylinders.

I'm sure Jesus at Riva has the answer you seek. It will need fuel and ignition tweeks per cylinder without the FA.