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Message-ID: <4BA1878D.6010804@gmail.com>
Date: Wed, 17 Mar 2010 20:53:17 -0500
From: Dave <david.staten@gmail.com>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Turbo Considerations....careful, its long
References: <list-4168879@logan.com>
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Chris... turbo's develop LOTS of heat... LOTS... they make lots of it on 
the front end compressing air (your intake charge could be 200 degrees 
or more from compression alone.. so you need an intercooler, which adds 
weight.. and complexity (popoff valve, plumbing).. then on the back end, 
instead of your 1800 degree exhaust going straight out an unobstructed 
tube you are going to take it, make this chunk of iron glow red hot, to 
the point its right on the limit of sagging/melting into failure, and 
make those gases spin a small wheel at over 100,000 rpm's.

It needs LOTS of oil, LOTS of insulation, LOTS of intercooling and lots 
of thermal shielding of the cowling, fuel rails, lines, wires.. If 
something can "see" the glowing red hot turbo housing or manifold, 
expect it to be damaged by radiant heat...
...
...

Or you could just increase your engine displacement by 50% and run 
everything at the same limits you would have with the NA 13B. A chunk 
more weight, but MUCH LESS complexity, several less genuine failure 
points, and a much more forgiving installation.

Who you want playing front linebacker for you in the superbowl? A 
quarterback hopped up on coke to get the most performance out of him? or 
some 300 lb linebacker who can play the line all day without breaking a 
sweat.

Thats one of the reasons when I spec'd things out for us years ago, I 
was pretty emphatic about a LIGHT turbocharging.. if not simply 
normalization..

Dave

Chris Barber wrote:
>
> I have been surfing the net 'til my eyes blur. I have read the 
> archives, which tend to topic shift just a bit <g>. I am all but ready 
> to pull the trigger on my turbo and wastegate purchase as, hopefully, 
> my welder will have my manifold ready soon. I have been using an Asian 
> knock-off turbo to this point for planning/spacing etc, but it should 
> be about time to get the actual flight stuff. I have learned a whole 
> lot about turbo operations and theory, however, The problem is, the 
> more I tend to get informed the more overwhelmed/confused I get.
>
> I could just punch in the info from John Slades set up. A Turbonetics 
> T04E-50 big shaft tangential with P trim and a Tail 46 wastegate. This 
> is also very close to the turbo the Grrrls are using (different Aspect 
> ratio, 9.6 v 1.15) Current pricing for the T04E is about $1100.00. It 
> is about $400 more with ceramic bearings....heck, point of 
> confusion...do I need ceramic bearings.....it cost more....it must be 
> better, right?;-) Also, there are widely varying prices on what seem 
> to be very similar, but not exact turbos. Drives me crazy not 
> completely understanding if the differences matter in my usage.
>
> The TiAL wastegate is around $500.00...ah, but a "Performance" 
> brand wastegate is "only" about $350 (I must have spent about ten 
> hours reading various forums on the glory of TiAl verses 
> Performace...yeah, at home recovering from surgery gives you this type 
> of net time). Heck, for that matter an ebay Asian knock off is only 
> about $80...tempting, but NO! (but hell, for all I really know, the 
> Asians may be making one hell of a solid wastegate...just figure this 
> is the wrong place to put blind faith...but for that matter, the 
> Performance wastegate may be made in China anyway <heavy sigh>
>
> When "they say" wastegate is 46...is that 46mm and if so, where 
> exactly is that measured? I do know now, sortat, that a 
> larger wastegate is better for controlling lower boost and even kinda 
> understand why so the MUCH cheaper TiAl 38 is not in the picture here.
>
> The problem with just punching in John's info and running with it is I 
> don't have the understanding to be an informed buyer. While price is 
> NOT the controlling factor, it pains me to just throw money at 
> something in a blind manner IF there may be viable options. When it is 
> all said and done, it may be punching in John's numbers. I know he and 
> the Grrls did their homework. I do NOT want to reinvent the wheel but 
> I would like to know why the spokes are made out of wood, so to speak.
>
> I was reading about a 20b using a Garrett GT4088 Journal Bearing Turbo 
> 1.19 A/R - which is selling for $899. Then there is Dave Leonard who 
> makes reference to a, IIRC, BNR turbo. Don't know anything about that 
> brand....I have at least heard of Garrett but do not know if 
> the GT4088 would do for a 13b that it would do for a 20b.
>
> When I look up the Turbonetics, while the part number I list is the 
> T04E, the returns include the T3/T4 combination designated in the 
> profile. Uh, I was thinking that meant is was a hybrid, which, as I 
> understood it, we do not want. Or, does that have some other meaning 
> that I am unaware? Is there a secret handshake that I do not know 
> about? I have read the info on choosing a turbo on the various 
> websites, but there is much information presented that presumes a base 
> I obviously do not have <sigh> and also geared to auto needs. As a 
> rule, I really do not care or need fast spool up.
>
> It is my understanding that turbo selection is both art and science. 
> Nice if it is your passion and you live for learning every nuance, 
> however, I am just trying to understand the "standards". Great thing 
> about "standards", there are so many of them...and in this case I am 
> beside myself trying to figure out how the standards to one 
> manufacture transfer to another.
>
> I am not looking for huge power gains...yeah, we all seem to say that. 
> But a bit more power, esp on take off (gee, have I heard that 
> before?????) and of course, normalizing, would be sweeeet. Especially 
> in my heavier Velocity. Al G did it with a 20b in the same kit 
> airframe. However, that ship has sailed for me.
>
> Actually, that brings up another issue I have been curious about. Why 
> so much preference to a relatively hard to find and expensive 20b over 
> a turbo??????? I noticed it routinely in the achieves. I understand 
> the 20b is more powerful out of the box and the conventional wisdom 
> seems to say the 20b is simpler...tubo's add complexity. Well, the 20b 
> does have an extra moving part <g>....but, unlike the turbo option 
> the 20b does not do much for you in thin air, the turbo does. Also, 
> a 13b turbo install would still seem to be lighter than a 20b N/A 
> install. What am I missing or do we just really like the cool factor 
> of the 20b (no disagreement there from me).
>
> I once again throw myself at the mercy of the collective wisdom for 
> edification. While y'all pine away on it all, I will be confusing 
> myself further doing some more surfing and remind myself of the other 
> questions I meant to ask.
>
> As always, thanks.
>
> All the best,
>
> Chris Barber
>
> Houston, GSOT
>