wolfdragon
Senior Member
Joined: April 2011
Posts: 287
|
Post by wolfdragon on Apr 24, 2011 0:37:31 GMT -5
I have been lurking the DIYGT yahoo group and was told to come here , so here I am
I am planning on making a small GT with the hopes of putting a freepower turbine behind it later....
As this is my first attempt, I am wanting to not break the bank on the first shot...
I understand my first turbo choice was very poor (bad inlet outlet area mismatch), but I think I have found a suitable victim:
ebay item 150456535909 $140 Compressor 2.00 x 3.00 0.50 A/R 57 Trim Turbine 2.58 x 2.25 0.64 A/R 76 Trim
Which gives me a Turbine OUT Area vs Compressor IN area of +21%
Being a cheap no-namer I know that I will have to go easy on it...
Sanity check on whether or not it "should" work please? (It's 1:30am...)
Thanks in advance, Wolf
|
|
|
Post by racket on Apr 24, 2011 16:59:12 GMT -5
Hi Wolf
Just checked it out on Ebay , looks OK , single port turb scroll , thats good :-)
Its a 44 Trim comp ( good), not the advertised 57 Trim which isn't that good for a GT .
Yep , don't put too much backpressure on her and keep temps down to 1450 deg F for a turbine inlet temp , or ~1200 F TOT . and keep rpm below 110,000 , maybe even only 100,000 initially just to be on the safe side , this is an inexpensive turbo so will probably not be as strong as a regular turbo ....................max P2 of 15 psi gauge pressure to start with to give a bit of a safety buffer .
DO NOT fit a jet nozzle onto the engine until you've run it several times and have collected reliable operating data that indicates it will be safe to start putting backpressure on the engine
Happy building :-)
Cheers John
|
|
wolfdragon
Senior Member
Joined: April 2011
Posts: 287
|
Post by wolfdragon on Apr 24, 2011 17:56:47 GMT -5
How do you know it's a 44 trim? Obviously there's a bit of experience to tell but it's still a curiosity.
As for taking it easy on her... I plan to monitor Ts and Ps at all stages as well at some intermediary steps for grins and giggles. I will be using one of my trusty embedded microcontroller boards with a fistfull of analog inputs and digital I/O to monitor (an eventually control this thing). But yes, I plan on taking it nice and easy and getting a good map of stable parameters before I start putting some back pressure on the system.
Thanks Wolf
|
|
|
Post by racket on Apr 24, 2011 19:45:23 GMT -5
|
|
wolfdragon
Senior Member
Joined: April 2011
Posts: 287
|
Post by wolfdragon on May 26, 2011 19:45:50 GMT -5
does the equation change for the turbine? (it looks like it should be EX/IN to keep small/large and thus make sense for some funny number I am getting)
|
|
|
Post by racket on May 27, 2011 0:17:57 GMT -5
Hi Wolf
Its always the smaller diameter squared, divided by the larger one squared , multiplied by 100 .
Cheers John
|
|
|
Post by turbochris on May 29, 2011 9:14:31 GMT -5
the good part here is if you're up at 1:30 playing with turbines then you have the correct amount of obsession. Pretty soon you'll be "angle grinder masturbating" like the rest of us.
|
|
|
Post by Johansson on May 29, 2011 9:29:30 GMT -5
Second that! ;D
|
|
|
Post by Richard OConnell on May 29, 2011 21:06:53 GMT -5
the scary part is that it has been around 1:30am for 35 days now according to your message.
|
|
wolfdragon
Senior Member
Joined: April 2011
Posts: 287
|
Post by wolfdragon on May 30, 2011 10:19:00 GMT -5
yeah I don't usually have free time during the day to work on stuff and I usually hit the board after I have had a chance to put some time in the GT, which is always after work...
But it's memorial day and I get that day off
|
|
wolfdragon
Senior Member
Joined: April 2011
Posts: 287
|
Post by wolfdragon on Jun 13, 2011 0:23:51 GMT -5
I need to resize the pictures for posting, but here's a vid of my combustor section, just a rough firing test with the shop vac and a tiny propane tank on a ball valve.
Injector is a sintered stainless pneumatic muffler, figured it would probably be a decent place to start before I tried to flatten some tubing and whatnot.
Details are posted in the vid description on youtube.
By the way, what was the howling sound it did before the bottle started to freeze up and lost pressure? It was louder than the video makes you think it was...
|
|
|
Post by ernie wrenn on Jun 13, 2011 8:09:42 GMT -5
Excellant burn... I like the stainless muffler idea, kinda original..
ernie
|
|
wolfdragon
Senior Member
Joined: April 2011
Posts: 287
|
Post by wolfdragon on Jun 13, 2011 8:23:07 GMT -5
I'll have to post pics of the whole combustor after I resize them, 5.1megpix is just excessive for data space
I was a bit surprised to not see a blue burn, I will hook up a proper propane grill tank when I get a chance to get in the garage again.
I am thinking that the run wanted a lot more fuel, will see if I can't map out lean and rich ends of the spectrum.
Also, is the amount of swirl excessive? When it was really cooking there was still a 1/2" air gapbetween the fire and the flametube wall. I doubt I have unburned fuel exiting the FT ( fire was maybe an inch out the end of the tube during the hottest part of that run). When I would slam the fuel open, the flame would extend out a few inches and then suck right back into the FT...
|
|
metiz
Senior Member
Joined: April 2011
Posts: 297
|
Post by metiz on Jun 13, 2011 9:56:58 GMT -5
Build's realy starting to get of the gorund, good work. The howl you hear was probably the flame "locking in" to the fundamental frequency of the pipe (correct me if I'm wrong here John(?))
|
|
|
Post by ernie wrenn on Jun 13, 2011 15:08:20 GMT -5
once you cap the end and start building pressure the flame burn will change dramaticly.
Ok john... Let's get the EXPERTs opinion...
ernie
|
|