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Project Fuel Injected Turbo FZR250, half

Discussion in 'Your 250cc Projects' started by Mike Green, May 9, 2020.

  1. Mike Green

    Mike Green Well-Known Member Premium Member

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    Power should increase, plus hot intake air causes an increased risk of detonation. A really easy test to illustrate why power increases is to get a 2L plastic milk bottle, slosh a bit of boiling water around inside to heat the air, tip it out and screw the lid back on. Run cold water over the bottle. It will collapse to 1/4 of it's original volume.
     
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  2. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Or that time I unscrewed the fuel can to let it vent in the heat, nipped it back up without thinking and came back to it crushed when I remembered I'd closed the cap whilst it was relaively hot...
     
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  3. Mike Green

    Mike Green Well-Known Member Premium Member

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    I've been messing around with my TIG welder trying to do half decent welds on 2mm aluminium. After most of a bottle of Argon, and hours watching YT videos, I more or less have it sorted out. Good enough to stitch something together anyway. Hopefully "the force" won't be so disturbed in future when I'm TIG welding. Getting a tack across both edges to start turned out to be a real challenge for me.
     
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  4. jmw76

    jmw76 Well-Known Member

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    TIG welding Aluminium is an acquired skill. Satisfying when you do a good weld though. I am certainly a long way from an expert. The main trick is to make sure everything is clean to start with. That initial tack can take some time to master without blowing holes in everything. When I started out, I often found that I wasn't using enough current, for fear that my work was all going to end up in a puddle on the floor. I also found I got better results with a bit more bias towards the cleaning cycle.
    Put some pics up of your progress so far.

    Peter.
     
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  5. Mike Green

    Mike Green Well-Known Member Premium Member

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    totally agree on being too cautious with the current. I'm now in the "lots of current and go for it" camp. I also have the balance a bit on the "cleaner" side. My practice pieces are a big mess with my experimenting so just a bit too horrible to put on line, except maybe on the "I can't weld for ****" FB page. I spent a couple of hours this arvo mocking up the plenum between the throttle bodies and the bottom of the intercooler core.
     

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  6. Andych

    Andych Moderator Staff Member Premium Member Contributing Member Dirty Wheel Club

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    If they are your welds on the 2nd pic you dont have to worry... they look fine. Not stacked dimes but who really cares.
    I delved into aluminium welding recently fixing my Golf Cart, wasnt pretty.....
     
  7. Mike Green

    Mike Green Well-Known Member Premium Member

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    I just fused the lip of the stubs into the surface of the plate. No filler rod so no stacked dimes. Plenty of penetration so I reckon it's as strong as it's going to get. Using my mate's rotator would have made it look pretty good
     

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  8. Mike Green

    Mike Green Well-Known Member Premium Member

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    Talking to my mate Kev today about welding and fitup of the 2mm plate to the intercooler. We got talking about types of Tungsten we are using. I do have pink which has been fine and I have bought a packet of white(zirconiated) 1.6mm which supposedly is ideal for AC so good for aluminium. I've tried them but to me they seem just a touch small for the combination of amps and balance with a relatively large ball forming. I leaned towards 2.4mm, pink because that was all I had that size. They seemed to work OK only forming a convex curve end on the point. Kev handed over a packet of 2.4mm zirconiated tungsten because he had no plans on using them. I'll give them a test run tomorrow. I also borrowed Kev's rollers as I want to get nice even curves on the 2mm plate when I'm making the chambers on the intercooler. I'll also make the cooling air ducting to the intercooler a bit nicer if I can make nice curves. Time to start cutting and shaping 2mm aluminium tomorrow.
     
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  9. jmw76

    jmw76 Well-Known Member

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    Never used anything other than 2.4 tungstens as that is what my torch is set up for.
    Mostly use white but have used red when in a rush and too lazy to change tungstens. Doesn't seem to be a big issue at the end of the day. Also when the tungsten getsa hot the colour coding disappears. So when you swap them around you can easly loose track of what type of tungsten you are using.
     
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  10. jmw76

    jmw76 Well-Known Member

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    this is what my welding work looks like these days. still not super pretty, but more than adequate.
    weld.jpg
     
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  11. jmw76

    jmw76 Well-Known Member

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    Tube is 100mm with 3mm wall. plate is 9.7mm. Gussets are 6mm. I have to wind up the current on my welder for this. The torch gets bloody hot after a while requiring a few breaks during the process.
     
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  12. gregt

    gregt Well-Known Member Premium Member

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    Mike, going back a ways, the first plenum chamber I made for the blown 500 Kawa was in 2mm alloy.
    It was destroyed by the inlet pulsations of the 180 degree twin running at 15psi boost.
    Next version was in 1.6mm mild steel - which survived. Incl a couple of heavy backfires on starting which opened the
    pressure release/safety valve
    If we'd continued with that bike the next step was to get a local to do us a carbon fibre plenum as we were told it would be more resistant to pulsations.
    The inlet pulsations in your 180 twin are an order of magnitude smaller than the 500 - but watch for any splitting.
     
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  13. gyro gearloose

    gyro gearloose Active Member

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    what size core is that? i spent many hours tracking down small bar and plate core... eventually found some at a good price, but by then i had already hacked up a cheap extruded one... meh, even OEM ones can be welded to once the (plastic!) tanks are pulled off. just not so easy to shorten...
    someone once mentioned industrial epoxy... never tried it!

    welding ali is easy yet fiendishly tricky. my main issue is the shakes... hidden, never be seen again? perfect. feature weld, critical? grind it out and leave it for a week until it wants to behave itself... theres no point pushing once it goes wrong!

    and the slightest of drafts will cause hours of frustration.

    can take a lot of playing with settings. my main gripe with mine is lack of footpedal. but my last one did have a pedal, but rather than limit to what was set on the panel, it would go "full range". not nice at 30A doing paper thin stuff! so, you win some, you lose some...

    can get away with ramp/slope times, to a degree. takes practice...

    so, no footpedal but i have frequency, clean area width... and clean area depth?
    seems mine controls just how much current it delivers on each side of the AC waveform, not just duty cycle...
    i like running 110Hz, "A"... low frequency tends to penetrate more but stay in place, high frequency gets rather "fluid" yet shallow... usually 30/70 on the width. havent played with depth enough yet and no-one else seems to have it...

    then theres simply sharpening the electrodes!

    can weld ali with an old buzzbox stick welder. its scratch start, its hard... but it works? sometimes it seems worth learning to gas weld the stuff... (le-dan!)

    other than certain jobs where the extra elements are needed... a rods a rod. some light a bit easier and some deteriorate a bit faster... for most part you wont notice the difference. pushing boundaries, they start to become apparent.
    my local shop only sells thoriated and zirconiated anyway.

    wha? lanthanium, cerium?
    bunnings sells a multipack...

    as for pulsations, fatigue, and ali... theres the "oilcan effect" of large flat surfaces... always worth embossing a flat surface for plenum chambers subject to pulsation... hammer/press grooves in, a cross, a circle, whatever... something to shorten any potential tuned length and aid rigidity...

    it isnt the thickness that matters, its the high frequency vibrations, the cycles of stress.

    anyone else notice FZRs get a harmonic drumming sound on the top of the tank? and wondered why they have that square embossed there?
     
    Last edited: Apr 27, 2024
  14. Mike Green

    Mike Green Well-Known Member Premium Member

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    An interesting conversation in the garage this arvo. We were talking about compressor maps and how the IHI RH31B turbo won't be getting near the efficient part as there simply isn't the air flow happening at the boost. More air needs to flow but the little engine won't let it. The thought was to bleed charge air to increase airflow through the compressor. This would only be done once boost was made so would not effect the rate at which boost was made. I'm thinking it could be the way that boost is controlled and the wastegate could be eliminated completely. Something like a blow off valve which opens once the desired boost pressure is achieved. All the exhaust gas would pass through the turbine all the time. Until close to the desired boost all the charge air would enter the engine. If the turbo was more closely matched to the engine there might be a chance of over revving the turbo but with this little engine I doubt it would happen. There will still be a restriction to flow resulting in pressure(boost) just that there will be a lot more airflow. I won't try it just yet but I will fabricate a small flange on the intercooler plenum where a BOV could be mounted later.
     
  15. gyro gearloose

    gyro gearloose Active Member

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    SURGE!

    thing i see as the issue here is the volume of gas feeding the turbine is far less than the volume of gas passing through the compressor.

    um. did i ever link to the billet compressor wheel for the vz21/rhb3? there was also another compressor housing and slightly larger wheel, VQ29 iirc, that fits but the wheel needs its superback trimmed by 1mm. unfortunately you want to go the other way, less airflow!

    sounds like youre one step away from going anti-lag...

    delving into areas i dont wanna delve into...

    excess air... can blow it out the back... can heat it up and blow it out the back... fill in that "void" left behind as you rapidly vacate the area...

    can stuff it into small combustion chambers to keep turbines spooled up... AND dump it out the back... bear in mind that certain fighter planes gained extra thrust from the exhaust and radiator...

    if you cant use it for power directly, then at least try and use it to assist the power you have aerodynamically?


    but if you start thinking of getting rid of the compression stroke altogether... youve gone too far!

    or have you?
     
  16. Mike Green

    Mike Green Well-Known Member Premium Member

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    Got the kitset plenum ready to go. If I'm completely honest with myself I've probably been procrastinating a bit getting this together due to doubts about my welding ability.

    Bit of a funny comment yesterday when I mentioned using cardboard to mockup air ducts and stuff that I was doing CAD - Cardboard Aided Design.
     

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  17. Mike Green

    Mike Green Well-Known Member Premium Member

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    Welded, sort of. It won't come apart as I made sure of as much penetration as possible. I had to practice repairing a hole in one corner. I backed out of it just a tad late and ended up with a hole. I need practice making pedal adjustments as I have difficulty when it starts getting hot. I back off a bit and end up with it getting gooey. It's also inconsistent but part of that will be me pissing around with different, or no, filler rod. Plenty of practice ahead before this is finished
     

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  18. jmw76

    jmw76 Well-Known Member

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    Your welding is looking fine Mike.
     
  19. Gen

    Gen Well-Known Member

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    More thinking like a gust of air, complete with methanol saturation, under pressure Build mk 2
    Match Port plenum2 002.JPG
     
  20. Mike Green

    Mike Green Well-Known Member Premium Member

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    Made a bit of progress with the intercooler. the top tank is finished and the throttle body to core plenum is tacked on until I sort out how I'm doing the connection to the turbo.
     

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