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Post by azwood on Feb 23, 2019 5:31:25 GMT -5
Hi Aaron Yeh , the bushfire season has been a bit of a bummer this year , now we've got high winds as well , by next week theres supposedly easterly winds with showers so maybe OK if I can dodge them . On my bike I used a needle valve with a throttle cable arrangement in place of the handle , this was only possible because of the "pressure differential valve" in the system which provided a constant pressure drop across the throttle irrespective of supply pressure/flow , by adjusting the size/diameter of the throttle cable disc on the valve handle I was able to produce a "sweet" throttle at the handlebar . On my karts I used more of a carburetor needle type arrangement that closed off an oriface to reduce the dump back to tank to increase fuel flow to the engine . Cheers John Yeah that's what I had in mind but where do you get something like that did you make it. |
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Post by racket on Feb 23, 2019 17:26:57 GMT -5
Yep , I made the one on the GT6041 kart and the one on my "Two shaft kart" had the "metering body" from an old Volvo car fuel injection system .
The bikes setup used a small hydraulic needle valve , 1/4" BSP threaded ports , it only required around half a turn of the spindle to provide enough throttle control from idle to full , the handle replacement was a disc of alloy with a groove for the throttle cable .
Cheers
John
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Post by azwood on Feb 23, 2019 17:39:17 GMT -5
Yep , I made the one on the GT6041 kart and the one on my "Two shaft kart" had the "metering body" from an old Volvo car fuel injection system . The bikes setup used a small hydraulic needle valve , 1/4" BSP threaded ports , it only required around half a turn of the spindle to provide enough throttle control from idle to full , the handle replacement was a disc of alloy with a groove for the throttle cable . Cheers John Ok thanks jhon I just see problems with the pwm. |
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Post by racket on Feb 25, 2019 18:38:29 GMT -5
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Post by madpatty on Feb 25, 2019 19:26:31 GMT -5
Congrats on the successful spool-up.
Cheers.
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CH3NO2
Senior Member
Joined: March 2017
Posts: 455 
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Post by CH3NO2 on Feb 25, 2019 19:28:34 GMT -5
The video looks fantastic but I can't really tell what all the meters are measuring. So far it looks like its running well at low P2.
How do you rate it? Is it doing what you want?
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monty
Senior Member
Currently being spanked by mother nature.......
Joined: September 2018
Posts: 400
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Post by monty on Feb 25, 2019 19:44:36 GMT -5
It lives!!!
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Post by racket on Feb 25, 2019 19:46:33 GMT -5
Hi Guys
Yep , its up to design Pressure Ratio of 3.5:1 .............all up ~6.5 minutes of run time before the engine started sucking air from the fuel tank .
I'm still getting a big difference between the two thermocouples ,so some fueling issues , though the T2 minus T1 figures are looking pretty good with calculated efficiencies in the high 70s to 80% .
Theres some discrepancy between my P2 gauges , but one is picking up from the diffuser exit and the other is connected to the propane start gas manifold and its picking up static pressure from just inside the flametube hole that the propane injectors feed through.
Despite several minutes at high temps the turb wheel is only showing a bit of "blueing" of the shiny surfaces .
Spoolup was very quick , I was up to nearly 34,000 rpm before I knew it and disconnected the starter , the better gas delection from the exducer has made a big improvement with a higher idle with the old fuel setting , I think I'll be able to cut he starter at 25,000 .
I'm slowly working throug this vid and another of just the gauges to get an idea of whats happening ............... but I'm a happy guy , she's getting closer :-)
Cheers
John
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Post by racket on Feb 25, 2019 19:48:08 GMT -5
Hi Monty
Yep , she's alive ...............thanks to your help with the bigger wheel , its behaving more like a "normal" engine at last :-)
Cheers
John
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Post by turboron on Feb 25, 2019 21:33:45 GMT -5
John, ready happy that you succeeded in getting your baby to walk upright. Now that she is walking we are looking forward to her learning to sing.
Thanks, Ron
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Post by racket on Feb 25, 2019 22:23:06 GMT -5
Hi Ron
Might be time to put a bit of backpressure on her ;-)
Cheers
John
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Post by racket on Feb 25, 2019 23:45:05 GMT -5
Hi Guys
I've been going through the "numbers" and noticed that my "hot" thermocouple has changed sides , its now where the "colder" one was ...............something strange has happened , maybe a fuel manifold problem , though it checked out OK with some propane prior to assembly , but >200 C degrees difference between one side and the other is cause for concern :-(
It seems that fuel flow rates are less at the different P2 pressures than previously , so thats a plus
Cheers
John
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Deleted
Joined: January 1970
Posts: 0
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Post by Deleted on Feb 26, 2019 3:41:34 GMT -5
 Wonderful John, am so pleased she is running, and for a good long time Wonderful All The Best Andy
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Post by racket on Feb 26, 2019 4:04:26 GMT -5
Hi Any
LOL.............your engine is getting so close to completion , I've had to get my finger out and crank her up , it was an overcast damp morning without any wind so nice and safe to give it a go.
Still issues with the thermos which I find hard to understand as nothing was changed with the fuel manifold .
It was nice to see her winding the P2 gauge around the dial :-)
Cheers
John
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Post by enginewhisperer on Feb 26, 2019 4:19:45 GMT -5
awesome stuff!
that must be a relief!
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