On Thu, 9 Dec 1999 Shaun.Hendricks@bergenbrunswig.com wrote:
[...]
> Now, I'm not sure I'd go with a twin turbo setup on a 6er. Your gains in
> pressure would be minimal as compared to a large Varible Geometry turbo. The
> VG Turbos also simplify the installation since they don't need wastegates.
> They have a simple pressure relief valve on them, not a wastgate. I'd rather
> have the force of a single large turbo than mess with the balancing headaches
> of twin turbos. The small twin turbo setup would be to eliminate turbo-lag,
> but that's what the Variable Geometry does on the larger Turbos.
>
> I'd talk to Allied-Signal (Garrett) and see what they have to say if someone
> is serious about turbo-charging their dak. Banks is another good turbo, but I
> don't think they have a Variable Geometry unit.
What about the recent discussion regarding the longevity and complexity
of the VNT turbos? Based on that, it seemed almost as if they were more
trouble than they're worth?
I'm just in "sponge mode" at the moment. :-) Reading all I can, looking
for info wherever I can find it... I've got a few books on the way, and
amoung other things, I hope they'll help me with some of the engineering,
and get me familiar with those strange looking turbo maps I've seen posted
on some web sites. :-)
Speaking of web sites, I found this one: http://www.turbocharged.com
Unlike many resources, its actually got prices (wow!) :-) I just bought
the latest issue of 5.0 Mustang magazine because the whole issue was about
turbo'd mustangs, but there wasn't a dollar sign to be found in the
whole issue! It did give me some food for thought though. Anyway, back
to the site... Based soley on the descriptions on this site, I'm thinking
a pair of Turbonetics T4 series turbos would work pretty well on the 318/360.
I don't know for sure, but I'm assuming this is a Garrett T4 with some
modifications by Turbonetics, for reliability and such? Anyway, according
to the description, a single T4 can support 300-550hp, and if you're
doing twin turbos, they will support over 1,000hp on 100-500ci motors. The
next step "down" appears to be their T3/T4 hybrid (where they use a T3
turbine and a T4 compressor), but they only support 250-450hp, and of course,
a plain T3 is even less. (I'm looking for 600-800hp, eventually.) The
next step "up" appears to be the T60, but it seems to be aimed more
towards competition, and its twice as much money.
The T4 looks to be anywhere from $650-$730 each, depending on the
particular wheels and housings you choose. (There are also additional
options for more power and/or reliability.) Anyway, that gets you the
complete turbo assembly including the compressor wheel, housing, and turbine
wheel. Of course, this does not include all the extra stuff you will need
like intercoolers, custom headers, wastgate, bypass valve, custom
intake tubing, fuel management, etc.; this is just for the turbo. I don't
think that's *too* bad though; for a twin turbo setup, you're looking at
under $1500, and when you consider blowers start at around $3K, you can
buy a lot of tubing for the $1500 you saved. ;-) (I've seen another site
that had remanufactured turbos for around $300-400. Remanufactured = same
housing, brand new internals, blueprinted and balanced.) This is all
assuming there is an "easy" way to increase the fuel flow. I'm guessing it
can be done similar to the way blowers (and nitrous) do it, but I haven't
given it a tremendous amount of thought yet. (yet) ;-) I'm planning on
using an aftermarket EFI system though, so I'm not *too* worried about
this. I won't have to fight the computer to get it do do what I want,
I'll just tell it to give me more fuel, and it will. (What a concept!) ;-)
I also came across an interesting little device in my travels; a
boost controller. You can do this already with the VNT turbos, but
for a turbo with a wastegate, you just have a little knob on your dash,
and when you want more boost, you can just crank it up a bit without
even getting out of your seat. Try that with a blower. ;-) (Argh; I
suppose that is going to incite a blower vs turbo war now... Oh well, as
long as I learn something...) ;-)
Oh, BTW, Shaun, could you elaborate on the "balancing headaches" you
referred to regarding twin turbos? I assume you mean keeping both turbos
at the same boost levels? If so, what makes it difficult, and why is it
desireable to have them both exactly the same? (Even if one is at 6psi
and another at 7psi, they both route to the TB, so wouldn't they average?)
Could a single wastegate be used for two turbos? Or is this more a
function of different exhaust properties from each bank of cylinders?
(Wow, I'm incredibly annoying!) ;-) Many thanks in advance, and three
cheers for anyone who has actually bothered to read this far! :-)
-Jon-
.--- stei0302@cs.fredonia.edu ----------------------------------------.
| Jon Steiger * AOPA, DoD, EAA, MP Race Team, NMA, SPA, USUA * RP-SEL |
| '96 Dodge Dakota V8, '96 Suzuki Intruder 1400, '96 Kolb FireFly 447 |
`--------------------------- http://www.cs.fredonia.edu/~stei0302/ ---'
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