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  1. #1
    CLASSIC MUSCLE's Avatar
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    Installed RIVA Thru-Hull & Lost Speed?

    My 14 FZR went from 69.4 stock to 72.7 with only SCOM and RIVA Power Filter. I was very excited with the gain from those 2 parts and dropped it off at dealer for 10 HR service and installation of RIVA Rear Exit (didn't want to cut on hull myself). Picked ski up tonight and it ran 71.6 will full tank and best I could muster was 72.0 with 2/4 bars. Was totally surprised to actually lose a little speed by doing this mod, I was expecting to gain speed, not lose it! Still have to put on the ribbon delete and haven't touched the prop or plate yet. I'm shooting for high 70's on the stock ECU eventually. Don't have my tach installed yet so I don't know peak RPM's. Is this too much exhaust for the ski right now?


  2. #2
    lets race.... mikeFZR's Avatar
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    Exhaust gains are lower in the RPM range. Not that you should lose speed from the mod, but I just wouldn't expect anything on the top end. Let me ask a couple questions though to clarify: your max speed (ever) is 72.7 right? Have you ever been able to duplicate it? or do you typically run high 71s - low 72s? if thats the case, I suggest you re-try a couple speed runs. Im not very familiar with the SVHO (I have a SHO myself), so the exhaust could have put you on the limiter which may cause you to loose speed. Sounds like you need a tach.

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  4. #3
    CLASSIC MUSCLE's Avatar
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    Yea, before I was hitting 72.5 pretty consistently with 1-2 bars and peaked at 72.7 the other morning. Air temps were 5 degrees cooler that morning than what I had tonight (75 vs 80) and humidity same. I will say that tonight I started my runs with 4/4 bars and the fuel load seems to really suck speed out of this ski. I ran 71.6 with 4/4 and got up to 72.0 on 2/4 bars before calling it quits. I suppose it's possible I could match the 72.5-72.7 run if I go back out in the morning and run with 1/4 bars again. So basically you're saying that exhaust really doesn't give you more top end speed, correct? So if I run the same speed as before this mod that's kinda expected?

  5. #4
    Branden's Avatar
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    It's hard to see what is a loss or gain if you don't do things on the same day especially a mod like that. Weather conditions and changes can cause a fluctuation in performance. I know my ski and slamdcoops neither lost or gained any rpm changing exhaust around

  6. #5
    Site Admin Green Hulk's Avatar
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    Your ski can lose/gain a mph on any given a day due to ambient temp changes, barometric pressure changes, etc.
    Exhaust won't give you more speed unless you are running high boost/high RPM and even then the gains are small. The biggest gain is that sweet sound


  7. #6
    lets race.... mikeFZR's Avatar
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    Quote Originally Posted by CLASSIC MUSCLE View Post
    Yea, before I was hitting 72.5 pretty consistently with 1-2 bars and peaked at 72.7 the other morning. Air temps were 5 degrees cooler that morning than what I had tonight (75 vs 80) and humidity same. I will say that tonight I started my runs with 4/4 bars and the fuel load seems to really suck speed out of this ski. I ran 71.6 with 4/4 and got up to 72.0 on 2/4 bars before calling it quits. I suppose it's possible I could match the 72.5-72.7 run if I go back out in the morning and run with 1/4 bars again. So basically you're saying that exhaust really doesn't give you more top end speed, correct? So if I run the same speed as before this mod that's kinda expected?
    Ya I would say as long as you are running the same speed you're OK. As others noted, it could be a number of factors.

  8. #7
    TyH2009's Avatar
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    Need some sound clips!

  9. #8
    CLASSIC MUSCLE's Avatar
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    Thanks guys, I'm feeling better about it now. Going to try and duplicate the conditions of my previous best run and see if I can match that speed. As for the sound, it's great. Nice rumble at idle, little to no unbearable drone, and just makes the ski sound more muscular. It's actually a little quieter than I expected as you can't even really tell the difference at like 5,500 RPM and above. From 2,000 to 4,500 it puts out a nice authoritative note though! I went this route because people were all complaining about the drone of the Free Flow.

  10. #9
    when I bought my 2015 FZS it ran 70.4 all stock (water was 78 air 80) then I checked it again when the water was hot (water 83 air 93) and it ran 68 but as it turns out I think I put regular in it by accident (too many beers) so I ran all that down and put 93 in it and it ran 70.1 in hot water / air (water 87 air 100)

    all of these checks were with a full tank of gas and the ski is still all stock

  11. #10
    CLASSIC MUSCLE's Avatar
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    I might have jumped the gun with this post. Went back out tonight with 2/4 bars and ran 73.1 peak speed with 72.5 mph being a good average. I've learned that these FZR's do not like a full fuel load. These skis really are temperamental when you're trying to get top speed. I had no idea some extra fuel weight made this big a difference! Very happy to say I didn't lose any speed with the exhaust, it was all "user error!" Need to get my plate to Jim, delete the ribbon, and get my Solas on. What do you guys think I'll be running after that?

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