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  1. #1
    desperado's Avatar
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    MSX150 -- a few test results

    I have been testing a few setups on my MSX150 since the beginning of the year. Overall, I have improved the top speed performance by around 5mph. Below are speed results achieved with different setups. All tests were done at the same location and were measured with a Garmin GPS. Although time consuming, I performed each test with 1 setup change at a time to understand the effect of what I was doing.

    In achieving top speed gains, I have noticed a degradation in hookup. Although the ski will now do 65mph consistently, I feel I'm at a point where I need to trade-off at least 1mph to regain hookup and increase the fun factor in less than perfect water condition.

    One conclusion I have to draw from all the testing is that the oem impeller does a very good job both from a low end & top end perspective. Nujet impellers had the best top speed performance, however were not as strong as swirl designs for low end performance. In my opinion, the oem impeller modified with +1* degree at the trailing edge should be as good as I will ever get from any other currently available impellers. That being said, I still look forward to testing a Nujet 5.5 or perhaps a Solas Concord 14/20.

    The challenge with the turbocharged Weber is to avoid loading the engine too much at engine rpm below 6,800 and loading it enough at wot while running additional boost. On that subject, I have reasonnable experience at increasing boost on Bosch Motronic based ECU's and the ME7.4.4 on the MSX150 & 110 is very challenging to bypass & modify for extra boost. I have been able to increase boost by 2psi over stock.... but beyond that, the ECU always find a way to regain control of the absolute boost by closing the ETB. Anyway, 2psi additional is ok (total is now around 16.5psi) and translates into an rpm increase of around 300rpm from stock.

    Here are my test results. Please understand I do not pretend or imply having the absolute truth or being an expert.... I just thought I'd share part of what I have learned.
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  2. #2
    Moderator beerdart's Avatar
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    Good stuff keep it up...

  3. #3
    Rocky_Road's Avatar
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    Great to see this!

    Any idea what would have been the result of changing the thermostat, without removing the exhaust deflector? Or...vice versa?

    And...what does it mean "intake fresh air"?

    I printed out your chart...hope that you don't mind.

  4. #4
    800AMSOIL4U's Avatar
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    I would love to see pictures of the fresh air intake and what you call the exhaust deflector removed. Thanks for all of the info.

  5. #5
    ph2ocraft's Avatar
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    Quote Originally Posted by desperado View Post
    I have been testing a few setups on my MSX150 since the beginning of the year. Overall, I have improved the top speed performance by around 5mph. Below are speed results achieved with different setups. All tests were done at the same location and were measured with a Garmin GPS. Although time consuming, I performed each test with 1 setup change at a time to understand the effect of what I was doing.
    Awesome to see somebody pick up the ball and take a run with it.


    In achieving top speed gains, I have noticed a degradation in hookup. Although the ski will now do 65mph consistently, I feel I'm at a point where I need to trade-off at least 1mph to regain hookup and increase the fun factor in less than perfect water condition.
    Are you going to experiment with an AAT and see if you can keepyour 1MPH and increase your hook up?

    One conclusion I have to draw from all the testing is that the oem impeller does a very good job both from a low end & top end perspective. Nujet impellers had the best top speed performance, however were not as strong as swirl designs for low end performance. In my opinion, the oem impeller modified with +1* degree at the trailing edge should be as good as I will ever get from any other currently available impellers. That being said, I still look forward to testing a Nujet 5.5 or perhaps a Solas Concord 14/20.
    Have you tried to taking some material off the nose cone area as well? Don't quote me but I think some of the guys were taking off like .040??
    I recall it was for better hook up while they were still increasing top speed.

    The challenge with the turbocharged Weber is to avoid loading the engine too much at engine rpm below 6,800 and loading it enough at wot while running additional boost. On that subject, I have reasonnable experience at increasing boost on Bosch Motronic based ECU's and the ME7.4.4 on the MSX150 & 110 is very challenging to bypass & modify for extra boost. I have been able to increase boost by 2psi over stock.... but beyond that, the ECU always find a way to regain control of the absolute boost by closing the ETB. Anyway, 2psi additional is ok (total is now around 16.5psi) and translates into an rpm increase of around 300rpm from stock.
    That's pretty cool, my Bosch rep was told you couldn't get in to "fool" the system or make changes without the system correcting it. Great to see you could at least make some change, especially for 300 RPM. Care to share the secret??

    Here are my test results. Please understand I do not pretend or imply having the absolute truth or being an expert.... I just thought I'd share part of what I have learned.
    Thanks for sharing, GREAT stuff!

  6. #6
    ph2ocraft's Avatar
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    Quote Originally Posted by 800AMSOIL4U View Post
    I would love to see pictures of the fresh air intake and what you call the exhaust deflector removed. Thanks for all of the info.
    My guess is seat off. If that's so, it seems like some more holes in the boat would be in order.
    Exhaust deflector...Resonator or waterbox?
    Last edited by ph2ocraft; 07-27-2008 at 09:19 AM.

  7. #7
    desperado's Avatar
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    In regards to the above...

    Fresh air intake involved taking one of the two 3" vent hose and routing it directly to the turbo compressor inlet. This is a direct routing to outside air and the whole circuit prevents any hot air from the engine bay enterinig the intake tract.... the only exception are two 3/8" holes at the bottom of the ducting system to eliminate any water that could eventually enter the 3" duct.

    The exhaust deflector I'm talking about is the small black aluminum deflector which bolts to the transom (outside) and is retained by two 1/4" bolts. Not clear what the performance gains are but definately a more direct exhaust flow path.

    Thermostat: just do the 160* degree thermostat modification. Running the oem 180* degree thermostat is more fuel efficient but at the expense of increased detonation potential, hotter combustion temperature and leaner fuel setting. In addition, you will immediately decrease your engine bay temperature by 20* degrees. From a performance perspective, turbocharged engines are safer with lower coolant temperature. The right thermostat to use is the one used on all 2007-2008 Polaris FST snowmobiles.

    The extra boost on the Bosch Motronic can only be achieved while the engine is operating in open loop, meaning under high load. The reason for this is because the ECU uses two boost pressure sensor which is somewhat uncommon but very smart to manage turbo lag. The principle is that the ECU monitors the boost pressure delta between the pre and post throttle body assembly.... and corrects the turbo boost to preset values programmed in the ECU. If the delta between these two intake areas is outside the ECU expected value, then either an overboost code is triggered or an error code is logged into the ECU memory. Once this operating principle is understood, a good tuner will conclude to leave the boost alone and at factory settings at all times except during open loop operation, that is at WOT. To design a good system to achieve this goal, a parallel boost controller must be installed and connected to a throttle switch which turns off the oem boost controller at WOT and turns on the parallel boost controller at the same moment. The great thing about this design is it enables the engine to run totally stock at any power levels other than WOT.... whcih is where you need the power anyway. There is one specific with the ME7.4.4 compared to the M7.4.4 (among others).... the electronic throttle body versus the mechanical throttle body on the snowmobile version. The reason I mention this is the extra design challenge proposed by the electronic throttle body: it will close and reduce boost if it senses a boost spike over an expected value. I found a solution to this: a boost delay timer... . The principle is when I press the throttle to the bars (wot), the boost goes to the stock expected value which is about 1 bar or 14.5psi.... for 2 seconds.... then an electronic timer switches on the parralell boost controller and voilà... 16.5psi or 300rpm extra! Without the boost timer, the boost would go immediately to 16.5psi and the ECU would close the ETB thinking there is a boost spike issue to manage. As I said before, Randy from Watcon sent me many goodies to test and to thank him for that I will send him the detailed schematic of the above -- he'll be free to share/sell/do whatever with it.

    Al.... I'm not too sure I understand your comment about the nose cone and the 0.040" shaving.... care to elaborate?
    Last edited by desperado; 07-27-2008 at 11:07 AM.

  8. #8
    SPEED KILLS, BUT YOU GET THERE QUICKER Keddano's Avatar
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    Very Good Research,Thanks for sharing. As I posted in my Project thread.I have a ride plate down at Jim's Performance being reworked.I'm planning on sending it out to a few guys that will do side by side comparisons. Some boats with Jim's modded plates have picked up,up to 4 mph. You might want to look at truing your hull up too for some more Free MPH's, My 150 hull was pretty straight from the factory,compared to alot of hulls I've seen.

  9. #9
    SPEED KILLS, BUT YOU GET THERE QUICKER Keddano's Avatar
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    Randy is getting in some more of these in the near future. Which would address the rear exhaust deflector you mentioned.
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  10. #10
    AWA Member 32DegH2O's Avatar
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    It will be interesting to see what a NuJet 5.5 will do. You mentioned hook-up and low end issues with the NuJet. These can be modified to correct the problem and be made to be as good as the swirl design...yet maintain the top end performance.

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