Date: Tue, 10 Sep 2002 08:18:10 -0700
Reply-To: Mark Keller <kelphoto@HIGHSPEEDPLUS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mark Keller <kelphoto@HIGHSPEEDPLUS.COM>
Subject: Re: Turbo question Water Jacket Seal failure
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Gary,
Gary Lee wrote:
> ----- Original Message ----- >
>
>
> > >
> > Yeah, the location is really stinky for being in the slop for the rear
> wheel,
> > But I think you could tuck up enough, probably by the time it's high
> enough to
> > drain back in the engine oil crankcase, it'll be out of the way of road
> spray,
> > if you ever visited any place where it rained. Seriously though if the
> supply
> > is pressurize would it not just accumulate in the drain hose until it
> reached a
> > gravity drain path back to the crankcase.
>
> I don't know how it would work with the vanagon and whatever turbo is used,
> but past experience has shown that
> I always needed a good gravity drain. If the oil does not have an easy
> place to go, it backs up and pushes past the turbo bearings and you get lots
> of smoke.
>
> > >
> > >
> > > > On the heat issue some research on the inertness and applicabity of a
> > > > silcone compound being used to replace the current OEM VW waterjacket
> > > seal.
> > > > I believe a silcone based waterjacket seal if produced would cure the
> > > > dreaded waterboxer leaking.
>
> >
> > An excellent point. The case threads would need inserts, it not already
> > done. Any chance of augmenting with exterior tensile support? I guess
> it
> > would be a risk with case inserts and hope for the best. The heads
> taking the
> > extra strain might be a deal breaker. With the stress fractures at the
> head
> > boss, and spark plug threads a common complaint, adding boost seems
> unwise.
> > Are the new AMC heads considered an improvement in this respect?
> >
>
> I would be pretty lazy about this whole thing if I did it. I would not want
> to pull and rebuild the WBX, just did that a year ago.
> I was thinking of just doing what I could with the stock engine.
> Personally I think an engine conversion is the way to get more power.
I agree about not trying to making a pony into a racehorse. This light weight
rear engine was a key part of the delivery truck design. The main feature
being aft polar moment. This allowed tires, read lower technology tires, to
turn a heavy vehicle without undue wear. A lot of refinements made this a
quite serviceable vehicle platform, and then a need for a more refined motor.
I'd do the engine conversion to a Subaru, because weight is the real issue.
The inlines are hefty and I believer throw the balance of the vehicle off. I
flew Bell 206 Jet Rangers for the US Military, and am sensitive to improper
weight and balance issues. The Syncro can take an inline diesel, because of
the VC unit and extra front hardware; but every thing else needs all the
consideration you can give it.
I'm curious about the propane conversion, how do you like it, and what kind of
range, and power difference do you notice.
>
>
> >
> > I run a 50 psi system, via an adjustable fuel pressure regulator, so my
> inject
> > duty cycle is lower than stock, I'd just test the motor with boost until
> > leaning occurred, i.e. from .86 volts at WOT and 4400 RPM to less than .5
> volts
> > on the O2, not a real lean. Actually I'm pretty certain the OEM digijet
> was at
> > least 112 hp on the Euro's so maybe my high pressure setup would cover the
> > issue.
> > >
>
> Yes, just try it out and see what happens.
> I'm curious, why do you run at a higher fuel pressure?
I read that higher pressure through the same orifice resulted in a smaller fuel
droplet. The more fuel Droplets, the greater the total surface area of the
incoming fuel charge. This results in a quicker and more efficient burn. So
there is a power increase. The new outboards are ultra-high 700 PSI systems,
for the same reason. Likewise diesels run in the 400 psi range. I was
pleasantly surprised by the gain. Horsepower wise it's not known, but and
extra 5 hp is still and extra 5 horsepower. Also the later digifants are rated
at 5 horsepower less than the earlier digijets. The only difference is the O2
loop. I've noticed when doing open loop testing that the engine more
powerful. The closed loop, has a slight cycle of rich ---lean, that
effectively means you running optimum lean half of the time, and not near
optimum rich, as in power rich, half of the time. Whereas the digijet, can just
run optimum rich or near it all of the time.
This of course is a trivial issue, until you come to a good grade. The O2 vs
open loop test meant almost 4 miles an hour difference. I don't run open loop
unless I'm tuning, but with the added fuel pressure and open loop, the motor
makes more then enough power run at highway speeds, even pulling a 3000 lb
trailer. Here's why,
At high speeds in my automatic, the engine is at 4000 rpm. that's 2000
firing cycles a minute an eight cylinder engine at highway speeds turn near
2000 rpms and has 1000 firings cycles a minute. 1k x 8 cylinder = 8000 firings
a minute. and 2K x 4 cylinder = 8000 firings a minute.
Real world the 4 cylinder piston are slight smaller, and that 8 cylinder
engines often need more than 2000 RPM to pull a loaded van and trailer, my
train weight was not under 7500 lb.. The real trick is that the Boxer can do
this high duty cycle power output for a long time-- especially sweet on a motor
that weight less than 300 lb. fully dressed--Quite a feat!
BTW I did do an open loop stretch from Portland Oregon to Tacoma Washington
pulling this trailer. The van ran 65-70 at will , it was really unnerving to
feel the engine that strong, I just had this sense that I was going to pay for
it. That was two years ago, and the motor had 100k plus on it then. It's still
rock steady and strong as ever. So maybe a Turbo would work ok after all.
Sincerely,
Mark
>
>
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