stevie
Junior Member
Joined: November 2020
Posts: 55
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Post by stevie on Jun 30, 2022 22:30:31 GMT -5
dude.
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Post by racket on Jul 14, 2022 4:08:43 GMT -5
Hi Guys
Bit of an update , the comp was posted off to get tested for material composition two weeks ago ................it hasn't arrived :-(
Postal Servive will start investigation in 3 weeks time , so alternative arrangements have been made with the spare wheel which we'll get tested and depending on its composition a decision will be made to proceed or not .
So sitting around doing nuthin'.
Cheers John
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praendy2203
Veteran Member
Joined: August 2020
Posts: 160
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Post by praendy2203 on Jul 18, 2022 15:22:45 GMT -5
Hi John,
That was not expected.
I hope, they will find the package.
The wheel is scrap, but worth to know the "ingredients"
Andy
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Post by racket on Jul 18, 2022 17:13:46 GMT -5
Hi Andy
They finally "found" it , and its gone for testing :-)
Cheers John
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Post by racket on Jul 18, 2022 21:05:13 GMT -5
Hi Guys Whilst waiting for the comp issues to sort themselves I thought I'd have a look at water injection , its been a very long time since I did , theres now a lot of inexpensive misting nozzles available as well as pumps . I purchased a set of 10 X 0.4 mm oriface nozzles and their mountings off Ebay for ~$AU15 , and made up a "spray ring" ~8-9" dia , just big enough to fit around the outside of the inlet bellmouth . On mains pressure of ~40 psi the system flowed ~600ml/min , so I hooked it up to the water injection pump I had on the 12/118 engines interstage upstream of the freepower wheel , its good for 150 psi , but the "open" flow rate of 8 lpm proved too much when the restriction of the misting nozzles were placed downstream making the pump "pulse" as the internal overpressure switch kept cutting the power, at 150 psi the flow should have increased to ~1200 mlpm Bit of video youtu.be/lpQbxYqOlH0 I think I need to go to the large oriface sizes , either 0.6 or 0.8 mm to provide enough water flow , the engine probably needs a couple of lpm . Cheers John
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Post by racket on Jul 26, 2022 0:14:55 GMT -5
Hi Guys
Rotor is off to be balanced, Andrew sent up the spare comp wheel, which was a nice tight fit on the turb quill , turb exducer now at ~45 degree angle , it'll be interesting to see how it performs, hopefully it won't take long to get balanced , I'm keen to fire her up again , got my 20ltr drum of fuel brew made up today.
The "dead" comp tested as 2618 alloy , I guess the small superback of only 6 mm on the comp wasn't sufficient to cope with the 4.5:1 pressure ratio runs ............it stretched :-( it probably needs at least a 10 mm superback , the original TF15 comp that came with the CHRA had a 12mm superback , most of the KTS TF15 comps have 10 mm or more and are machined from stronger 7075 alloy
Cheers John
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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 Jul 26, 2022 8:50:05 GMT -5
The "dead" comp tested as 2618 alloy , I guess the small superback of only 6 mm on the comp wasn't sufficient to cope with the 4.5:1 pressure ratio runs ............it stretched :-( it probably needs at least a 10 mm superback , the original TF15 comp that came with the CHRA had a 12mm superback , most of the KTS TF15 comps have 10 mm or more and are machined from stronger 7075 alloy Cheers John John,
2618 is quite a bit stronger than 7075 at high temps. I can't remember the exact numbers, but at piston temps (400 F) it's something like 4X stronger than 7075. 7075 loses most of it's strength at higher temps. I'm not sure where the crossover point is. 6061 has the same problem, it also becomes very brittle over time at elevated temps. 2618 and 4032 Al alloys were both developed for aircraft pistons. Still used for that, diesel, and high performance piston applications. They both get stronger over time with exposure to heat, but the strength at room temp is low compared to higher strength alloys. It's deceiving though since the high strength alloys are so adversely affected by temp. 2618 is not necessarily a bad choice for a comp wheel. At 4.5/1 you may need some kind of cooling, or a TI wheel. A larger super back certainly won't hurt.
Looking forward to some progress for somebody somewhere! I'll post an update on my thread...not much excitement unfortunately.
Monty
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Post by racket on Jul 26, 2022 18:15:37 GMT -5
Hi Monty
Perhaps they use the 7075 because its less prone to erosion from the water injection used on tractor puller turbos that these larger KTS wheels are being used on , I don't know .
I'll be testing at 4:1 PR in future , and if theres still problems , I'll need to go searching for something stronger .
Yep , its been very quiet here on the Forum , I think there are too many Youtube videos available telling people "all they need to know ??" about building an engine
Cheers John
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Post by racket on Jul 27, 2022 1:10:28 GMT -5
Hi Guys New 10 X 0.6mm oriface mist nozzles arrived and fitted to water injection manifold . Spray rate is just under 2 lpm with pump working continuously unlike with the smaller 0.4mm nozzles Video youtu.be/ippGW2o2WI8Cheers John
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Post by racket on Jul 27, 2022 20:37:59 GMT -5
Hi Guys Started mounting the water injection manifold to the starter "spider" Not sure about the nozzle " approach angle" to the incoming air , I can always swivel the nozzle mounting pieces around so that all the spray goes "down the throat" , I'll give it some "forward" spray to begin with to hopefully improve the time available for cooling the air from evaporation ................trial and error required Cheers John
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Post by racket on Jul 27, 2022 20:39:40 GMT -5
OOPS where did my pics go
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slittlewing
Senior Member
Joined: November 2017
Posts: 458
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Post by slittlewing on Jul 28, 2022 15:56:52 GMT -5
Hi John,
Great work on the water injection mods/R&d and glad I managed to reignite your interest in it! I am keen to see your results and fingers crossed your next comp wheel does the distance 👍👍👍
She will be up and running in no time!
Cheers
Scott
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Post by racket on Jul 28, 2022 16:58:51 GMT -5
Hi Scott
Hopefully I don't need to wait too long for the balancing to be done , then a couple of days to get the engine back on the teststand and rig up the water , I'll try and be a tad more restrained in future , a quick run up to 4:1 PR dry ,then water added , then a wet run to 4:1 to get data before hitting the water for comparison numbers .................heh heh , thats the plan , hopefully I can remember to stick to it on the day :-)
Cheers John
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Post by racket on Jul 29, 2022 17:45:20 GMT -5
Hi Guys With the engines front comp cover mounted to the test stand I've been able to sort out mounting the misting manifold to the starter spider and get plumbing to the pump which is now wired up and mounted on the shelf underneath . Things are getting a little crowded Cheers John
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Post by pitciblackscotland on Jul 30, 2022 11:15:12 GMT -5
Hi John, will you be able to read the temp gauge when the water mist is on Cheers, Mark.
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