turbomarc
Junior Member
Joined: May 2015
Posts: 56
|
Post by turbomarc on Jun 11, 2015 18:46:31 GMT -5
I reckon that shrapnel is probably casting remnants from high quality construction methods If you want to change turbo I can donate a Mitsubishi TC06 turbo which has a smaller compressor and larger turbine than your ebay one - and is proven to work nicely as a DIY turbine. Otherwise I have a couple of larger truck turbos that could work nicely, but so far I found it difficult to provide enough starting air to spin them up! It always seems like a good idea to get the air to swirl around the combustor, but apparently it tends to cause uneven flow and more problems. Putting the inlet pipe away from the primary zone seems to help keep flow nice and even around there too. Hi Andrew, Cheers for the offer, I'll see how things pan out with the current turbo. But with the larger truck turbos how much larger are we talking here? Not that I'd be jumping on them right away, but just curious, like I mentioned I would like to go bigger down the track. John, thanks for the pics of the CC entries I had a bit of a think about it but I should be able to come up with something, I'll get it down on paper, and see what you think. Cheers, Marc
|
|
turbomarc
Junior Member
Joined: May 2015
Posts: 56
|
Post by turbomarc on Jun 10, 2015 20:10:26 GMT -5
Hey John, I found that page last night and joined, but I need to have my account approved by the people that run it before I can get access to the files and pictures. Yeah, not good having metallic flakes, but stuff it, I shall press on, I gave it a decent clean out, will still run it, and after a few fire ups pull it apart and keep an eye on the situation. Smithy, yeah with my extremely limited knowledge and near non-existent calcs, I'm extremely happy that it starts and runs. But as you said I'm happy to iron out as many issues and getting running as best I can while learning along the way. That way later on I will have some hands on experience and feel bit more confident to move on to a larger project later on. Just curious with the combustion chamber and where the air enters it, is there a optimum spot in relation to the flame tube that I should put it?? Closer to primary, secondary or tertiary?? Also I assume that it would be beneficial to make the air enter in such a way that it will swirl around the flame tube to help aid even flow?? Similar to a swirl pot for of design? Yeah I'd be happy to meet up for a test and tune day once mine is back in action, be good to have someone have a close look and get some more feed back. Cheers, Marc.
|
|
turbomarc
Junior Member
Joined: May 2015
Posts: 56
|
Post by turbomarc on Jun 10, 2015 5:20:06 GMT -5
Hi Marc Turbine wheel is a tad small for the sized compressor inducer ( mass flow) , we generally require a turb exducer with ~20% greater area than the comp inducer if we want to have adequate flow area out of the comp to allow the comp to flow at its best , you really need a turb exducer of ~64 mm to better match your 58.2mm inducer . Are those bits of "shrapnel" metalic ? Or are they carbon flakes from an oil leak from the turb seal forming coke behind the heat shield ? As for "comprehensive guide/rules" we had some "Rules of Thumb " in the Files Section over on the Yahoo DIY Turbines Group Cheers John John, i don't like my chances of getting a larger rear wheel or exhaust housing, would probably be cheaper to just buy a new turbo, i think i might just try and make the most of what i've got for now, while i cut my teeth on this and do my homework in preparation for maybe a larger frame turbo later down the track. There is a minor amount of the "shrapnel" that is metalic, that was the first thing i did was to get it all together then run a magnet thru it. Yahoo groups are still around??!?!?, Will endeavor to look them up and get reading. Thank god for the semi wet weather in Sydney today, afforded me a early finish from work, got the reducer cone welded up, as well as the new combustion chamber, i'm pretty chuffed, no grinder, only finished both inside and out with a wire brush after welding
|
|
turbomarc
Junior Member
Joined: May 2015
Posts: 56
|
Post by turbomarc on Jun 10, 2015 2:57:44 GMT -5
what are the comp and turb wheel dimensions , also the turb scroll A/R , there could be a mismatch of sizes that is causing some of those temperature problems. Hi John, I just remembered this earlier post of yours and thought while i have it apart i'll get some measurements for you, hopefully you can see something i can't, and it has a A/R of .63 As i mentioned earlier it's a ebay spec turbo, so the fact that it is still spinning is a bonus from here on out, but after i removed the exhaust housing, i rotated the small cover for the bearings and seals and it felt as if it was full of sand, after much fiddling around i seem to have got it all out thru the 1mm gap between the cover and the core housing. As you can see in the circle, the grit and shit that came out, it can't be a good thing. Now i know it might be a bit late in the game, but, majority of this build has been from rough guides i found online and some guess work, is there any comprehensive guide/rules to doing builds like this, as i'm really starting to think about perhaps another one, a bit more refined that i can try and make some thrust with, as opposed to just making noise and flames like i am now. Cheers, Marc.
|
|
turbomarc
Junior Member
Joined: May 2015
Posts: 56
|
Post by turbomarc on Jun 9, 2015 0:16:10 GMT -5
New pieces arrived today..... Cylinder that will become my new combustion chamber, and the pressed conical section for the transition from flame tube to exhaust housing of the turbo
|
|
turbomarc
Junior Member
Joined: May 2015
Posts: 56
|
Post by turbomarc on Jun 5, 2015 4:47:21 GMT -5
I figure, to make the collar seal on the flame tube properly, i would need to cut the dome section off the extinguisher, weld the collar in, then reattach to the rest of the tube, and after all that, still be stuck with the disrupted flow issues due to the vena contracta effect. So i might as well make a new combustion chamber, i got in touch with a local fab shop to do the rolling up of the steel today, should hopefully pick it up next week some time. It will be a slightly larger diameter, with the reducer to the turbo flange a removable section, and should flow a lot smoother than the current design. But where i have the inlet from the compressor housing, is there an optimum spot where it should enter the combustion chamber?? I noticed my current one blows straight in on not much of an angle, should i be trying to have it come in on an angle to encourage the air to swirl around the flame tube similar to this? Or it doesn't matter as much, as long as the air gets in there?? Cheers Marc.
|
|
turbomarc
Junior Member
Joined: May 2015
Posts: 56
|
Post by turbomarc on Jun 4, 2015 8:06:12 GMT -5
This is rediculous, in a good way.
One question for the likes of yourself and smithy, where exactly would you be able to take it out for a run??
|
|
turbomarc
Junior Member
Joined: May 2015
Posts: 56
|
Post by turbomarc on Jun 4, 2015 7:07:54 GMT -5
|
|
turbomarc
Junior Member
Joined: May 2015
Posts: 56
|
Post by turbomarc on Jun 3, 2015 4:46:27 GMT -5
Appreciate the offer Smithy, but should be sweet, i have made the fuel rail fairly long for the reason being, using compressor quick release fittings, and it should have the fitting about 100-150mm away from the combustion chamber depending on final location of the injector, and i will route the hose far away from heat sources, most likely thru the inside of the frame.
1mm drill bits, made by the devil, snapped two, got one hole drilled.... I guess if it was easy everyone would do it.
|
|
turbomarc
Junior Member
Joined: May 2015
Posts: 56
|
Post by turbomarc on Jun 3, 2015 1:12:42 GMT -5
Yeah, nice, the premade hose i got from the gas shop is the same thread as the air fittings, co-incidence, i think not!!! Should have the new fuel rail done tonight
|
|
turbomarc
Junior Member
Joined: May 2015
Posts: 56
|
Post by turbomarc on Jun 3, 2015 1:05:41 GMT -5
Yeah, all good, i might be able to out source some rolling, see how things pan out.
Plans fell thru using my mates beaver to cut a thread the full length of the fuel rail, but of improvisation, just drilled the centre out of some threaded bar.
Might be a bit of a stupid question.... What are your thoughts on using air compressor quick release fittings for gas??
Only reason being my current gas line is copper pipe, and doing this will allow movement on the gas line so i can adjust the position of the fuel rail.
|
|
turbomarc
Junior Member
Joined: May 2015
Posts: 56
|
Post by turbomarc on Jun 2, 2015 21:56:44 GMT -5
Thanks Chris,
I'll endeavor to see if i can make that idea blend, being its right in the base might make welding a bitch of a job, not impossible, just harder, might also be yet another good reason to make a new chamber from scratch, because one thing that i think could be done better in hindsight is where the air enters, maybe have it on more of an angle to encourage a smoother swirling effect around the flame tube.
Cheers, Marc.
|
|
turbomarc
Junior Member
Joined: May 2015
Posts: 56
|
Post by turbomarc on Jun 2, 2015 21:48:40 GMT -5
Hi Marc, Good to see your onto it....for the fuel injector, many people just use a long bolt with a hole drilled down from the threaded end through the center for the fuel inlet, but not right through the head end, maybe 1-2mm short of right through, then drill your 1.0mm holes from each hex face so they meet the center hole. Personally I'd start with slightly smaller hole in the hex, maybe 0.7mm, you can always easily make them larger if required, it's a bit difficult to make them smaller after they've been drilled..! Positioning of the fuel nozzle outlet can also be a bit hit 'n miss, might even pay to make it adjustable via a sliding mount maybe...doing a run and inspecting where the flame front starts and adjusting your setup to suit...just thinking out loud. With your welding skills I'm sure you could easily come up with a solution. I can't weld to save my life... You could always just make up a few different sized injector units ranging from ~0.5mm up to 1.0mm and experiment a bit....there's no hard and fast rule as each turbine build is slightly different even if they look the same. Smaller holes with higher fuel pressure tends to work well. We eventually would like you to run on liquid fuel such as diesel or kerosene as propane can become a tad expensive and it's a pain to constantly have to fill your propane bottle at the nearest petrol station. 20L of diesel will cost ~$25-@30 and last quite a while with your smallish turbine. When you get to the point of doing a few runs, I'd be happy to pop over and point or nod at things. I believe Andrew (enginewhisperer) is not too far away as well...maybe we could make an afternoon of it..! Cheers, Brett. Yeah, that's a good idea for the different sized jetting, as well as an adjustable fuel rail. Going to visit a mates workshop this afternoon, see if i can get my hands on some half inch tube, and chuck it thru the beaver, then i can have a running thread from end to end, then it is just a matter of having one nut inside, and one outside of the flame tube, and then adjust until desired result is achieved. As for jetting, nuts are cheap, isn't hard to grab a handful, put a cap on one end then just swap them over without having to remove the fuel rail each time. But i really can't see me being able to drill less than 1mm, i just don't have the equipment to deal with such precision, i think even with 1mm i will have to be ever so gentle with my hand drill, i doubt my pedestal drill chuck would even grasp a 1mm drill bit. For the time being as you said Smithy, gas is very forgiving, so for now i might just stick with it till i feel happy that i have got it sorted out and then progress into running a liquid fuel. Also diesel is "free" being a truck driver, 20l here and there is nothing in the grand scheme of things, but i also have a mate that has said if i need any Jet A1 he can supply me with a bit. Chris, yeah, i will be addressing that gap while it is all out at this stage, just build up the material on the end of the flame tube, test fit, grind, test and repeat until sorted, but the downside to that is, i'm still left with the domed end of the combustion chamber that will still leave me with that Vena contracta effect. Enginewhisperer, you wouldn't happen to have a sheetmetal roller by any chance would you, after finding out about the Vena contracta effect and how the domed end isn't the best way to funnel air efficiently into the exhaust housing, im considering making a new combustion chamber to suit my current flame tube. Happy to throw cash your way for the effort if it's something you could do. Test day sounds good, i live in Penrith, but work at Thornleigh so im up there six days a week. Thanks for the help thus far to all involved, much appreciated. Cheers, Marc.
|
|
turbomarc
Junior Member
Joined: May 2015
Posts: 56
|
Post by turbomarc on Jun 2, 2015 5:08:15 GMT -5
Wow, thanks for clearing that up for me finiteparts, yes I am more accustomed to a IC engine. I got home a bit early today, got some time to pull it apart and survey the inside of the combustion chamber, i'm a complete rookie, but i know when things aren't right. Appears as if i had some flames out of three primary holes, in one particular area. As mentioned earlier, can clearly see why copper wasn't the best choice, tho after having higher than average temp, and the occasional green flame, it's in better condition than i was expecting. On the inside of the combustion chamber, mixed feelings, was expecting to see heat colouration, just wasn't expecting to see it where it is. Made me start questioning had i lined the flame tube up right, was it off centre, but i ruled that out. Also, one issue that Smithy diagnosed on the weekend, was the fuel rail and where the holes are positioned, he mentioned that for best results, same as someone else mentioned earlier in this thread use some pipe with a nut on the end with 6x1mm holes, one on each face of the nut to give the 60 degree separation for a even distribution of gas. I used some of my finest mspaint skills to illustrate roughly what i think should be the new fuel rail, any advice would be welcomed. So plan of attack is to just change the fuel rail, and remove the jet nozzle restriction, see if that helps bring the temps down abit. Cheers, Marc.
|
|
turbomarc
Junior Member
Joined: May 2015
Posts: 56
|
Post by turbomarc on Jun 1, 2015 20:51:31 GMT -5
Nah smithy I wasn't around, as I said I would have liked to stay, but I had to take off about five minutes after speaking with you.
Yes, fuel rail and nozzle removal are the first two jobs, tho while I have the flame tube out I might as well try and get rid of the gap between the combustion chamber and the end of the flame tube.
|
|