[Vwdiesel] Turbo talks -- ( more qestions ) ????

[Val Christian]

Nice collection of quotes, Loren.  The practical questions remain.
Is there a turbo I can slap on my 91 NA when I rebuild (well rering
and valvejob it) this spring?

And to what benefit? Lower noise would be really nice, but apparently 
not really possible.  More power is nice, but in my opinion, not 
necessary, although my 17 yo son would strongly disagree.

>From what I've heard here, here's the comparison:


		NA		Turbo

Noise				just slightly less, induction noise high

power				increase

life				possible decrease, due to non-turbo
				rated pistons, cooling jets, smaller
				oil pump, etc.

reliability	good		likely good after debug time

starting			little likely change

protection			enhance heatshield


Candidates?			none mentioned

Other options	rebuild injectors
		adjust timing
		modify induction resonation for 70 MPH frequencies
		start using synthetics after rebuild
		consider different transmission (not likely due to cost and
			availability)
		larger wheels, as minor effect substitute for ratio issues	




Val

> 
> In a message dated 1/29/2004 4:00:12 PM Pacific Standard Time, 
> h_hagar at prcn.org writes:
> 
> > Does turbo charging shorten engine life ?.
> > Answer --- resounding yes yes yes. Simple grocery store logic. So if you 
> > bolt on a turbo using your NA engine --expect shorter life.
> 
>  From "Diesel Fundamentals, service, repair" page 124:
>   However, on one four-stroke engine, brake (hp) was increased 37.5%
> over the (NA) engine.  On another engine, the increase was 56%.  Such 
> increase is largely due to: 1) More complete scavenging. 2) Adequate air
> to support complete combustion. 3) Improved mechanical efficiency of the 
> engine.  There is no appreciable increase in friction hp with the increase in 
> 
> output."
> 
>   Page 127: (on efficiency and power increase)
>   It will be noted that at 2100 rpm of the (NA) engine, the hp is 240 hp, 
> while
> that of the supercharged engine is 320 hp.  When aftercooling is added 
> brake hp is increased to nearly 380hp.
>   Improvement in torque and fuel consumption per brake hp hour are also 
> impressive.  At 2100 rpm fuel consumption for that particular engine (NA) 
> was .425 lb/hp hour and the supercharger was .38.  Only a slight improvement
> was attained by aftercooling.
>   Torque improvement for this same engine was 675 for the (NA) engine, 
> 875 for the supercharged engine, and 1025 ft. lb. for the supercharged and 
> aftercooled engine."
> 
>  1980 LA Times: (on Motor Trend/BAE cross country turbo Rabbit run)
> "Volkswagen also said it questioned the wisdom of turbocharging the 
> Rabbit because, a spokesman said, Volkswagen believes the turbo 
> device puts an extra strain on the small diesel engine that might 
> cause a variety of types of damage.
>   BAE emphatically denied Volkswagen's contention.  BAE's president,
>  Robert McClure, said five Rabbits equipped with the company's 
> turbochargers have now logged 150,000 miles each with no appreciable 
> extra engine wear."
> 
>   he goes on to say they offer replacemet warranty to cover costs that vw may 
> 
> refuse to cover.  (something not done much yet, at that time.)
> 
>   There's mention in another article about same or better wear 
> characteristics 
> likely due to the more even loading of the piston rings.  Something I read 
> at Jake's, I believe said that the better scavenging and cooler combustion 
> temperatures contribute to LONGER engine, or at least component life than 
> in a NA engine.  Cooler rings, less soot buildup, less lugging.
>   I've yet to read any article that contributes shorter engine life to 
> turbocharging.
> Lot's of hearsay that it does with NO examples cited but nothing tested or 
> even printed.  The only example I've seen was a nearly holed piston.  Sure 
> the turbo contributed to the severity of it IMO but the CAUSE was a bad 
> injector.
>      Loren
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