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  1. #1

    1100 zxi d1 or d2 stinger modification

    never been in this forum but i hope u guys are more technical than others forums.

    i am planing to modify my stock exhaust system and add a stinger to the pipe to improbe my top end by adding a fitting and a 200 main jet, will install a jetworks set to open arround 5000 rpm.
    i need some advice on water routing and fitting placement as good as other modifications to the exhaust.

    does any body know how to modifcate the stractor/pipe hose to dry the water box and bypass the water to the manifold, i saw it before i n one forum but don't find it anymore.
    any advices and pics are apresiated. thank you.

  2. #2
    raiderx72's Avatar
    Join Date
    Jul 2007
    Rocky Hill, CT
    ZXiman's used to be on pwctoday exhaust mods had a 70mph zxi.. This was not written by me nor have i done it but i hope this helps.

    The 1100ZXi exhaust system is adequate for stock power levels and actually works quite well. However, once you modify your ZXi, you will want to address the exhaust system question. There are a couple of aftermarket (single pipe) exhaust systems on the market. I have tested them each of them. Yes they improve power. Unfortunately the question is not how much power increase is available but rather, where the power improvement is coming from. In my testing 80-85% of the power gain came from a $25.00 timing advance plate (6 degree advance). The other gains were mostly the result of careful manipulation of water being injected into the pipe. In my opinion, not worth the $900-$1100 asking price. You can add the same water "manipulation" features of the aftermarket systems to the stock system. I have what I call the Dominator 2 (D2) exhaust modifcation for the 1100 Kawasaki applications, which does not use a timing advance plate, but rather, makes power from the exhaust system and not advancing the timing as part as the "exhaust" question. It is a well known fact that the exhaust manifold on the 3 into 1 single pipe exhaust as used on three cylinder personal watercraft, is by far the biggest bottleneck as far as performance and horsepower is concerned. Due to design features built into the manifold, it is not only very restrictive, but also inhibits "multi-port plugging" (a quasi-pseudo exhaust scavenging which occurs on 3 into 1 systems). Since there are three exhaust ports opening or closing at any given time in the cycle, there is no such thing as a "tuned" pipe 3 into 1 system because one port may be opening, one port may be closed and another may be opening or closing, all at the SAME time. Basically the "sonic sound wave" never makes it back to the exhaust port and is wasted. So, think of your big 3 into 1 exhaust system as just a big "muffler".

    How do I modify the stock system to improve power you may ask? I extensively modify the exhaust manifold so that there is less distance needed (between each exhaust port) to be travelled to "plug" each cylinder.This is done by reducing the "deflectors" within the manifold. I open up the manifold port runners 2mm and the manifold "collector" up to 3mm and match the headpipe to the top of the manifold. I then install a 150 Keihin main jet to the main chamber jacket, which is under the 1/4" "L" bend brass fitting (the hole just needs to be tapped), and I by-pass some water which comes from the stator cover to the pipe fitting. To improve holeshot & mid range acceleration and to facilitate more overall flow, I enlarge the "stinger" section of the pipe from 54mm to 57mm. I then add a dedicated 3/8ths water line to the stinger (reducing size down to 1/4" line where it connects to a 1/4" brass fitting) and tap in a Keihin 200 main jet. I use a 3/8ths Jetworks valve set to open at 5000 rpm. The overall effect is that for roughly $400.00, you can pick up as much as 15-18 peak horsepower (and about 200-225 rpm) while increasing torque from off idle to peak rpm. Our race pipe is loosely based on the D2, but is designed with acceleration in mind. Performance bewteen the aftermarket pipes and the modified OEM one is very similiar, except that the increase in power is from the EXHAUST and not an increase in timing advance.

    The OEM 1100 waterbox is more than adequate for stock level performance, but as you increase power can be modified to flow better and manage water better at any given rpm range. The easiest way to get a slight increase in performance and to reduce back pressure would be to take a 1" holesaw and cut a hole in the rear baffle. As far as my full waterbox modification that we sell here at PE, we actually cut the box in half, make additional changes to the flow through tubes, baffle and exiting tube for a 75-100 rpm gain. But the 1" hole in the rear baffle will offer an increase in performance you can feel and it is free. Just don't cut a hole in the exit tube while cutting the hole in the baffle (easy to do if you are not careful, because there is very little room between the baffle and the exit tube).

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