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How much of a power up can you expect from a new pipe??

Discussion in 'Technical and Troubleshooting Torque' started by robsalvv, Jun 7, 2006.

  1. I have two dyno charts for my ZX9R.

    One dyno run in the 2005 summer of my fully stock 2002 zx9R showing 126HP peak.

    And one done yesterday, with the bike in kerker slip on guise - no other mods. The chart showed 146HP peak.

    Though there's been an increase in power, and though I'd love to claim a 20HP bragging right for a slip on... 20HP increase seems a bit unrealistic.

    How accurate are dyno's?

    9R's are carby'd bikes. Could the weather conditions and configuration affect carby performance that much?? i.e., hot summer day stock bike versus brisk winter day sports muffler bike?

    Spose I should do a dyno run with the old pipe while it's still brisk for a true comparison...



  2. Only way to get an accurate comparison is to try both configs on the same day.

    I had the old girl on the dyno and got 97.6 and a year or so later after a major service and a K&N filter got 102. I'd say that's not unrealistic but the time and conditions varied so it's a guestimate at best how much actual change the filter made.

    Still, you have more HP than me so be glad...bastard ;)
  3. 1. - Air Filter
    2. - Exhaust system
    3. - Power Commander

    well that's what the sign said at Dynoverks ..........
  4. Seems a bit off to me.

    Was it the same dyno? Does it have the correction factor value they used on both of your print outs? An operator error may have been made there. Best to stick to the same dyno so that direct comparisons can be made, but not so in your case.

    Different weather conditions wouldn't alter the power by that much, even less with carbs. At best with just a slip-on you could probably expect another 5 or so hp up top and improved low-mid range (and a lot better noise!).

    I'm not too familiar with zx9's but more importantly than peak power, you should look closely at the A/F ratio after the changes. Some bikes alter dramatically even with just a muffler change, but if the operator was on to it, he would have fiddled with the carbs.

    Like deyago said, best if both runs are done on the same day. Does the bike go better? That's all that really matters.
  5. Just a vague stab in the dark, but was it even the same dyno? Not only do individual machines vary, but there are different types of dyno which will report differing numbers... for example, an eddy current dyno will give a much lower hp figure than a dynojet based unit.

    As suggested, you really need to do a back to back stock vs slip on to get a better picture. With tuning, you might get 5 to 10hp with a slip on - 20hp is above what most full systems 'claim' to produce.

    As for powercommander - unless you want to run multiple maps, remapping your stock ecu is a much cheaper and effective solution. Also one less thing that can fail at the worst time :)
  6. Different dynos, different conditions, different engine temps all help in getting varying results.
  7. Same dyno folks at Race Replica in Brooklyn. And they were dyno power runs to trace the power curve of the bike, rather than dyno tuning runs.

    Deyago... mate believe me, I am glad :)

    Lotus, Ninja 9R's don't have ECU's and maps... it's a carb'd bike so there are no map adjustments... but it's a fair suggestion for injected bikes.

    I agree that 20HP is a really big ask from a slipon... hence my question about the accuracy of dyno's.

    Anyway... at least I have a chart that I can use for bragging rights... 145HP! :) Nothing to sneaze at!!

    ...providing I ignore an article like the one here:


    which is all about dyno accuracy... and how results can be fudged. The impact of atmospheric conditions is interesting...
  8. Rob Ive had figures thrown at me for a can and headers on a Bandit 1200,of same same,up to 20hp bolt on performance,depending on can of coarse.They didnt mention air filter or rejetting and they werent selling me anything. :-k
  9. By itself, 145rwhp from a ZX9R, even with a slip-on pipe, seems pretty optimistic.

    20hp extra will give a noticably stronger seat-of-the-pants push. When you first had the new pipe on, did the bike feel like it was pulling dramatically harder with a wide open throttle?
  10. Cathar, not sure how to define "dramatically", but it definitely was a very noticeable power increase... and all I was really after was a bit of extra noise.

    Win - win. :grin:
  11. Movin, bandit12's are bit different to the majority of bikes in that the exhaust system is extremely restrictive and the engine is in a very understressed state of tune.

    It's true that a full system and minor breathing mods can gain you more than 20hp on these bikes. The earlier bandit 12 model yields a higher power gain over the later model type.

    zx9's (and most sports bikes) won't respond to mods as favourably as the big bandit as they are usually already in quite a high state of tune.
  12. you might very readily see 20hp from a dud to a new chain.

    Biggest response from an untuned pipe on a carbied bike would be the weight reduction.
  13. how big of a change were the atmospheric conditions?

    Stinkin hot to freezing cold + the can may do it.
    Its all about getting a bigger bang in terms of HP, thats why Nitrous works.

    Dense air coupled with a non-restrictive can may add say 13HP (estimate for illustrative purposes) on the day.

    Then you put the standard can on and run it on an unusually hot day, the result will sway away from what the bike would usually put out HP wise and be down a couple of horses, lets say 7HP.

    Theres your 20HP difference.

    So if the bike and conditions were neutral, one day your down on HP, the next your up, the difference looks a lot bigger on paper.
  14. "dramatically" as in power-weight wise, an extra 20hp would be the same sort of effect again as jumping from a ZX6R (~105hp) to your ZX9R (~126hp). You say you've just gone and doubled that difference. That's the sort of "dramatic" difference I meant. You'd feel like you'd just gone and upgraded from a 600cc bike to a 900cc bike again.

    When I first jumped onto the R1 (142rwhp) from memories of my VTR (110rwhp), that extra 32hp was a mind-blowing difference, at least until I got accustomed to it.
  15. ...in that case it wasn't dramatic... just very smile inducing noticeable.

    At any rate, since the kerker went on, the free revving nature of the engine has been unleashed. It just loves getting to the red line in a hurry.

    I think the atmospheric conditions and some dyno error explain the value of the apparent power up.

    But you've all confirmed that a can alone [except for a wheezy big bandit] should not result in a 20HP increase.


    Ciao for now.