Holset HX50 Supermoto Jetbike

[jetric]

  
  Hi Scott,
 You can try heating your oil up by using one of those paint stripping heat guns by blowing the hot air through your oil cooler with your oil pump running (your oil cooler is a effective heat exchanger). On the very early design of my DIY engine I did weld a 20mm pipe horizontally straight through my oil tank so I could attach a blowtorch to one end of it to pre-heat my oil, this worked quite well, but as the engine became more refined it became unnecessary for me to pre-heat the oil as when I used to do the runs at Santa Pod with the kart by the time I had got to the start line the oil was sufficiently warm and holding a steady good pressure. I've never had any problems due to lubrication and always used Mobil 1 motorsport 10W60 oil in my jet kart and my brothers jet kart. 

 Richard S.

Feb 5, 2021 14:03:28 GMT -5 slittlewing said:

Well I tried the Ebay heat pad with disappointing results. The aim was to get the oil circuit as hot as possible for the purpose of mapping PWM required to produce a given pressure. This will need programming into the ECU so it automatically controls the pressure correctly based on oil temp, as the oil thins during running.

The cheapo Ebay pad got way too hot and caused the silicone to smoke. It was so hot that attached to the oil tank, it burned the nice new paint job off 😡 I can’t repaint with the engine fitted so will have to vinyl wrap the damaged area. It feels like it was probably designed for US 120v Ac rather than Uk 240v

I then attached a lighting dimmer switch to run it at lower power. This stopped the pad smoking but after the oil travelled through the long circuit (pump, cooler, filter etc which were all cold) at low flow rate due to being choked by the turbo bearings, it hardly increased in temp.

So I will abandon this and try and map the oil as the engine warms up instead, once I get it running. I can control oil pump PWM on handlebar pot for now. I have also changed ECU code from dynamic oil pressure demand (P2 + 2 bar) to 2 bar during starting and 4 bar During running.

ECU has been reprogrammed to try “one button press” start and a ramp on the initial fuelling. Second handlebar pot controls idle fuel pump PWM at the moment.

The bike is ready to do static testing once again, once the UK is out of lockdown!

Cheers
Scott

[slittlewing]

Thanks for the suggestions John and Richard!

It seems you get what you pay for in this case, and my £7 Ebay heat mat is now in the bin.
Very good point about the heat exchanger (cooler) and heat gun, I might give this a go. I would have to be careful as my cooling fans are just plastic PC fans and my electric heat gun can output pretty high temps, don’t want them to melt haha.
I assume Richard that you are using either a pressure reg or bypass on your oil system meaning the pump speed remains high even when the oil is cold? With the 10w60 and my pump dead headed against the restrictive turbo, the oil pump motor was pretty much stalling on 10w60 and therefor hard to control compared to 0w30. Whether this oil is too thin when hot remains to be seen!

The vinyl wrap arrived quickly and I have sorted the paint damage to the oil tank.

I tried my ECU code, but didn’t want to spark the plug (in case some residual fuel in the lines ignited) so I attached the HT lead to the chassis. Upon testing the nee start routine, the 30kv spark unit obviously put a big spike back through the board and it killed the small transistors feeding the high side drives, causing all to run at 100% with no demand. ECU is removed again to replace the components.... trials and tribulations!!

Cheers
Scott

[jetric]

  Hi Scott,
  I use a electronic closed loop system to control the oil pressure on the Kart engine via a pressure transducer and a PWM to control the speed of the oil pump motor, this way I am not wasting any of the limited electrical power that I have on board the Kart.

 Richard S.

Feb 6, 2021 18:47:17 GMT -5 slittlewing said:

Thanks for the suggestions John and Richard!

It seems you get what you pay for in this case, and my £7 Ebay heat mat is now in the bin.
Very good point about the heat exchanger (cooler) and heat gun, I might give this a go. I would have to be careful as my cooling fans are just plastic PC fans and my electric heat gun can output pretty high temps, don’t want them to melt haha.
I assume Richard that you are using either a pressure reg or bypass on your oil system meaning the pump speed remains high even when the oil is cold? With the 10w60 and my pump dead headed against the restrictive turbo, the oil pump motor was pretty much stalling on 10w60 and therefor hard to control compared to 0w30. Whether this oil is too thin when hot remains to be seen!

The vinyl wrap arrived quickly and I have sorted the paint damage to the oil tank.

I tried my ECU code, but didn’t want to spark the plug (in case some residual fuel in the lines ignited) so I attached the HT lead to the chassis. Upon testing the nee start routine, the 30kv spark unit obviously put a big spike back through the board and it killed the small transistors feeding the high side drives, causing all to run at 100% with no demand. ECU is removed again to replace the components.... trials and tribulations!!

Cheers
Scott

[racket]

Hi Scott

Instead of the heatgun use the better half's hairdryer , more volume less peak temperature .

With your oilpump , run it on full power and have a pressure relief valve .....................for me ,"KISS" is essential when it comes to lube ..........LOL, and most things :-)

Cheers
John

[slittlewing]

Ah yes Richard I remember your closed loop controller now, it’s a neat little unit!

Good idea about the hairdryer John, that’s worth a try!
Funnily enough I was looking at ausjets use of a pressure reg for oil the other day and the details about the large bore “GFB” unit. It looks nice but they are quite expensive! Given i have the things I need to do PWM control and space on the bike is rather limited, I will try and proceed with the current setup for now. Once I have the temperature compensation mapped it *should* look after itself, fingers crossed.

Cheers

Scott

[racket]

Hi Scott

At times I've used automotive oilpumps for pressure relief and as a remote oil filter , 2 jobs in one item .

Maybe look at modifying one of these , www.ebay.com.au/itm/Oil-Pump-Ford-FWD-Courier-Escort-Fiesta-KA-Orion-XR2-1-0-1-1-1-3-1-6-OHV-engine-/310110483185 , even a secondhand unit could work with a few mods as you're not concerned about pumping efficiency

Cheers
John

[turboron]

Scott, check out the Oil Pumps thread under General Discussions tab. Wannnbuilderuk has a post on his use of the Ford Escort pump Mobil 1 motorsport 10W60 others. I am modifing a similar Nissan pump.

Thanks, Ron

[Sweetenough]

Hi Scott, to bad the the heat pad ruined the paint job.
Mine are hot so you can not really touch them when in operation (they are installed on an unpainted aluminum tank) but they seem to have some kind of built in overheat protection.
Notised this when I was suppling the heaters through a socket powermeter. Maybe that function was not included in yours...
Just out of curiosity, what mapping do you do against oil temperture?
Looking forward to a start-up of the bike soon.

Kind Regards
Thomas

[slittlewing]

Thanks for the info on oil pumps, if this was a larger build I could consider it but the Marco up9 I am using is quite a nice compact unit and has the grunt to produce huge pressure when required. At 20% PWM it is producing 4 bar with cold 0w30 oil!

I am sure I can control it well, I just need to sweep through the range of temperatures it will see during running hence the heater pad (or hairdryer).

Thomas to answer your question about control, I will note down the PWM required to produce say, 4 bar at temperatures between say 0 and 80degC and plot this on a graph. Apply a best fit line and then write the equation into the arduino code. The arduino then reads the oil temp during running and uses it to apply PWM accordingly. This is the “feedforward” part of the control.
Additionally I have a PID control that can be applied on top of this to close loop control. Of course this all sounds a bit complicated compared to a mechanical pressure regulator but.... it shouldn’t be that bad in reality

Cheers
Scott

[Sweetenough]

Aha, "feedforward" now we are talking!
Have not got that far on the Jetoped, "only" using PI controllers.
Thanks for sharing Scott.

Kind Regards
Thomas

[slittlewing]

Hi All,

I finally managed to get the bike reassembled and test it. 
I had a friend turn me another new spark boss on his lathe to suit plugs of a different type/length and I tig welded it in earlier this week - all so I could use my 2kv “hot spark” system.
Amusingly despite testing fine at 12v, with a fully charged battery the ignition unit blew, also damaging the relay pcb. 

I didn’t want to wait several weeks to put another 2kv unit together and test it etc....So I modified my old spark unit, removing the “gap tube”. It was previously suggested on here (enginewhisperer) that this might be the source of my emc woes and that has proven 100% correct!

Onto the test:


The new start routine I had programmed into the ecu worked perfectly second time, when I tried letting it light/pop first before adding air impingement (previously I was adding air first). The speed of the spool up took me by surprise somewhat!!

I tweaked oil pressure manually with increasing temp and noted the PWM needed as it warmed up. Next time I may try PID control.
The new thermocouple measuring units were much better, I saw 633degC on TOT at 2.1bar P2 (max throttle)

The mechanical changes I put in place to fix various leaks and issues look to have worked thankfully.

In terms of performance, clearly this turbo is flowing 20% more air as per the increased wheel sizes, also given this running was done with a 17.5GPH nozzle instead of 13.5 with old turbo (both fed at 10bar). The bottom of the combustor is also glowing much hotter than before! It melted my groundsheet haha.

I am wondering whether to go up again, now to a 21.5GPH nozzle to try and get more P2 (obviously pushing the TOT higher) Or whether to leave it as-is given the TOT will increase with afterburning. Any thoughts welcome!

Cheers

Scott

[ausjet]

Looks great! Can’t wait to see it on the road. Just no parking in any dry fields 😂 do you have control of your afterburner fuel pressure/pump speed?

[Sweetenough]

Looking great! The fastest spool up that I have ever seen :-)
Nice to see that it perform so good after all your modifications!
Is the bottom of the combustor made in carbon steel? Looks really hot, might consider changing to stainless? So it does not melt during operation.
Hope to see some afterburner soon :-)

Kind regards
Thomas

[wannabebuilderuk]

Mar 14, 2021 10:24:28 GMT -5 Sweetenough said:

Looking great! The fastest spool up that I have ever seen :-)
Nice to see that it perform so good after all your modifications!
Is the bottom of the combustor made in carbon steel? Looks really hot, might consider changing to stainless? So it does not melt during operation.
Hope to see some afterburner soon :-)

Kind regards
Thomas

I'm pretty certain Scott is using stainless for the c/c lid but I agree that looks a bit too hot compared to the rest

[racket]

Hi Scott

Looking good , nice spoolup :-)

I think I'd leave the fueling as is for now and see what happens with A/B activation , your "oversized" A/B nozzle might be allowing extra mass flow when running "dry" , once the A/B is alight and putting more backpressure on the engine the mass flow may reduce and your temperatures rise , you've already gone up ~30% with the fuel nozzle size which should be providing more than enough fuel for the larger comp , that's if the fuel pump/controls are allowing it to do so .

How are your fuel pressures compared to the "old" ones with the smaller nozzle ??

That red hot combustor cap will cool down a bit once you're mobile ;-)

Cheers
John