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Post by slittlewing on Dec 1, 2022 17:45:52 GMT -5
Lovely workmanship on your build!!! Looks fantastic. Your aluminium welding is lovely too.
I would try to drill out that cheap adapter to at least 4mm, before fitting a valve or regulator (for my 2.5” jetbike I used a 0-4bar propane reg on a large UK bottle).
Cheers
Scott
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Post by The Lazy Destroyer on Jan 6, 2023 23:51:00 GMT -5
Lovely workmanship on your build!!! Looks fantastic. Your aluminium welding is lovely too. I would try to drill out that cheap adapter to at least 4mm, before fitting a valve or regulator (for my 2.5” jetbike I used a 0-4bar propane reg on a large UK bottle). Cheers Scott Thanks for the kind words! I was able to work on it tonight. For anyone using a “QCC1” type adaptor like I pictured earlier, to connect a BBQ tank, the check/safety ball inside can be removed by drilling a 1/4” hole on the downstream/outlet side, until the drill bit reaches the ball. Then the spring and ball can be removed. I drilled the inlet side to 11/64” (4.30mm). Be careful as going any larger than that will risk breaking the nipple portion that extends out that pushes on the BBQ tank valve to open it. But 11/64” leaves enough meat on it to look ok. I tested the fitting to the tank and that internal check was what was preventing me from getting flow out the tank when there’s no significant back pressure. I do plan on having a needle valve at the engine to control throttle so it may have worked with the check ball in place, but I didn’t want to risk it or have that setup prevent flow rate. I also got the flame tube and injector done as well. Using 8 holes about 1/16” in side shooting outward at the primary holes. |
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Post by The Lazy Destroyer on Jan 7, 2023 15:07:49 GMT -5
Just an update: it runs!
Holy smokes it is loud.
Could only get two short runs since I forgot to charge the battery for the oil pump and oil pressure started to drop to the boost pressure level so I shut it down. And I have to work on starting procedures to be smoother. But no problem with the BBQ tank as it can really push some fuel in there.
Trying again tonight. But seeing it self sustain on first try was very nice.
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Post by racket on Jan 7, 2023 16:32:54 GMT -5
Congratulations :-)
Always good to get that first spoolup done
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Post by The Lazy Destroyer on Jan 8, 2023 13:25:57 GMT -5
A few quick videos for reference. First run. My throttle adjustments were pretty sloppy so the run was a bit erratic. I gave it just a bit too much fuel at the end and the boost pressure spikes and popped off the intake tube. It happened pretty fast. Run was I think around 8-10 psi (ended at 20+ something) but I can't recall exactly. First run: www.youtube.com/watch?v=OtsSQB1fQecSecond run. Shows the gauges. Easier start and sustains at 6-8 psi boost. T3 about 900-950°F (I did not have my T4 hooked up yet). Includes short walkaround showing the smokeshow ... just some WD40 on the bare steel sections burning off I guess. I briefly ran it up to 10 psi then back down, then shut down when I saw my oil psi was low. Battery powering it was weak, needed a recharge, so I stopped there. Second run: www.youtube.com/watch?v=nii3qnkdu4AThird run. Recharged the batteries and gave it a longer run. Hooked up T4 on the display. Played around with lower and higher boost levels. Seems there is a sweet spot around 5-10psi it likes to run at (based on T3/T4) but anything lower than 5 starts to run hotter (almost 1200°F) and I wasn't sure what is too hot so I tried to keep it at 1000°F and lower. Lowest I saw was about 900°F. Youtube killed the quality but you can kinda make out the temps in the video. It's a 30psi boost gauge so all the larger tick marks are 5psi increments. At 3:25 I run it down to 2ish psi to see what it does at a lower throttle, which it ran ok but the temps climb up to 1150 so I ran it back up to 5 psi to verify temps would drop back. Then shut it down. Third run: www.youtube.com/watch?v=430_9heJvF4 |
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Post by turbinenjoe on Jan 8, 2023 14:03:56 GMT -5
Congratulations for the successfull runs!
Very clean and tidy build.
Did you consider powering it with a 12V power supply for testing around the house? It can be annoying to be reliant on a battery.
Regards
Matthias
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Post by racket on Jan 8, 2023 15:36:54 GMT -5
Looking good :-)
We generally don't measure T3 as its "safer" to measure T4 as we don't want a thermocouple going through the turbine wheel , T3 can go up to 1450 F , so T4 ~1200F is probably high enough for your turbo.
P2 of ~5 psi is a normal idling pressure , any lower and its easy to get into difficulties .
Oil pressure needs to be higher , 45 psi -3 Bar will flow enough to keep the rotor cool as well as rotor dynamics under control .
A good progress and a tidy build :-)
Cheers
John
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Post by The Lazy Destroyer on Jan 8, 2023 16:30:20 GMT -5
Congratulations for the successfull runs! Very clean and tidy build. Did you consider powering it with a 12V power supply for testing around the house? It can be annoying to be reliant on a battery. Regards Matthias Thanks! I may end up doing the power supply method. I forgot to charge the battery before I tested the jet and assumed there may be enough juice for a few short runs. But a power supply would probably eliminate the hassle. |
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Post by The Lazy Destroyer on Jan 8, 2023 16:46:22 GMT -5
Looking good :-) We generally don't measure T3 as its "safer" to measure T4 as we don't want a thermocouple going through the turbine wheel , T3 can go up to 1450 F , so T4 ~1200F is probably high enough for your turbo. P2 of ~5 psi is a normal idling temp , any lower and its easy to get into difficulties . Oil pressure needs to be higher , 45 psi -3 Bar will flow enough to keep the rotor cool as well as rotor dynamics under control . A good progress and a tidy build :-) Cheers John The oil is something I need to look into. I set the pump to about 40-50 psi before the start, I did a fair bit of testing with the oil system and the oil pump will run up to 50-55 no problem for a long period of time, on it's own (no jet running). But when the jet was running yesterday, after about 30 seconds or so the oil would slowly start to get frothy in the tank, visible in the sight glass. It also seems the oil return line is spraying into the tank when the jet is running (indicated by oil on top of the fill cap which is normally would never do. Smoke is in the oil tank also when it gets frothy. The oil system always has that slow steady stream on the return line on the tank when running on its own, but doesn't appear to be like that at all when the jet's running. It's a cheap journal-bearing turbo, I'm guessing when the jet is running there is pressure pushing through into the oil/bearing area and making the oil in there frothy. And the frothy oil is causing the pump to lose it's ability to maintain good pressure. It drops down to about 20 psi or so when it gets frothy, another reason my runs were kinda shorter because it seems like something I need to correct somehow. The pump is a basic automotive fuel/oil pump. I put in very lightweight oil because I wasn't sure it was capable of pumping thicker oil, so there's 0w16 in there now. Should I try a thicker oil? The oil pump feeds to the turbo using the fittings provided with the turbo, and the oil inlet fitting for the turbo still has the small orifice. The return line goes to the tank and returns above the oil level. Oil tank holds about 2 qt |
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miuge
Veteran Member
Joined: March 2014
Posts: 200 
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Post by miuge on Jan 8, 2023 17:14:39 GMT -5
0W16 is very low viscosity oil and as it gets hot pretty quickly your pump does not have enough flow capability to maintain higher pressure. EFI fuel pump as seen on your setup is not recommended for such use either. Switch to let's say 10W30 oil which can stand the heat better and upgrade your oil pump to something else if cannot cope with it.
The pop which caused the intake tube to come off seemed more like "flameout" and re-ignition to me?
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Post by The Lazy Destroyer on Jan 8, 2023 23:26:39 GMT -5
0W16 is very low viscosity oil and as it gets hot pretty quickly your pump does not have enough flow capability to maintain higher pressure. EFI fuel pump as seen on your setup is not recommended for such use either. Switch to let's say 10W30 oil which can stand the heat better and upgrade your oil pump to something else if cannot cope with it. The pop which caused the intake tube to come off seemed more like "flameout" and re-ignition to me? I was a little worried about the pump I had. I’ll flush and refill with thicker oil and try again. And look for a oil pump like the gear pumps with metal heads. I’ve seen small 12v gear pumps made for oil on Amazon and EBay that seem affordable. |
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Post by The Lazy Destroyer on Jan 9, 2023 12:08:36 GMT -5
The pop which caused the intake tube to come off seemed more like "flameout" and re-ignition to me? Ahh maybe so? It happened pretty quick and at the time I thought it was from the P2 going past 20 psi. But looking back it almost happened after I closed the propane valve, which I probably closed to fast. Would that be a flameout? I’m pretty new to this so you’ll have to bear with me  I tried to be more smooth with the propane on the runs after that, which seemed to help a lot. I need to add a needle valve on the propane line. |
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Post by racket on Jan 9, 2023 14:48:18 GMT -5
You might need to flare the ends of the tubes a bit so that the clamps hold better , or fit a tie bar to prevent blowoff.
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Post by slittlewing on Jan 10, 2023 15:20:32 GMT -5
Ideally if you can weld on pre fabricated swaged tube ends, it would also help prevent the hose blowing off. I had to do this on my jetbike after a similar issue. Degreasing the steel tubing, using a fresh “sticky” silicone joiner and having a small gap also helps. Pic below Cheers Scott  |
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Post by The Lazy Destroyer on Jan 11, 2023 18:19:16 GMT -5
Wondering if that frothing in the oil is from boost pushing through the journal bearing. I am noticing very slight side to side play on the turbine and compressor wheels. It’s very slight, and the tips of the blades are not touching the housing, but I can feel a slight wiggle. I assume that’s bad :/
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