DIY_EFI Digest V5 #107

[Ken Thompson]

From:
Kevin Jaeger (Ken's Associate)

Bernd,

I apologise for my apparent heaviness of comment in relation to your
statement "K-Jet would be OK for boat". I have had 3 friends killed in 3
years due to boating accidents. I have a thing about reliability on the
water. I was not over impressed with the state pathologist having to dissect
a good friend, just so they could conclude he died by drowning. So I guess
the way I answered had more to do with that, than K-Jet on a boat, but I
stand by what I have said about K-Jet, not being suitable for a boat.

If Clair's engine was to be fitted to a beach buggy, I would have made no
comment. Now if we are talking boats, one needs to be sure that the system
is absolutely reliable, if not don't use it or recommend it.

All pleasure boats induct the spray of salt water (ocean going), it is the
nature of the beast. If the boat in question is for use in a fresh water
lake, filled with 4 feet of water, then this is all academic, as Clair will
never have to swim home, she can walk. No Salt Water Crocodiles in Canada
that I know of. I guess a 3 foot child would be in trouble if she / he had
to walk home, across a 4 foot lake?

I am sure you could do a great job rigging up a K-Jet that would function
wonderfully on the water (the first day). Two weeks later, I will bet the
second days fun will not be as much fun. One can construct well designed air
boxes, centrifuges etc and salt spray is still going to be induced. Seizure
of the actuator, the arm roller etc is likely to be a problem (air valve
arm). Might be fine the day of commissioning, but put it away and come back
in two weeks, rust will be a problem. Benz' and others you mentioned have
got pretty good air filtration systems, but I do not see one system in
amongst them, that could double as a watercraft water excluder (for want of
a more suitable description).

Who cares if Lucas' A/F ratio is not perfect, never said it was. It can be
set up pretty good www.kinsler.com Lucas was used in Formula One on down,
was very big in boats. A pleasure boat is more like a performance engine
than a street trim BMW. Not much stop start driving or gear changes. If 3000
RPM is where it will be driven, would be nice to tune for max torque there.
The Lucas (Triumph) bodies do lend themselves to simple set up for tuned
length runners. After a day on the water, give the each port a spray with
non waxing, dewatering compound. The Triumph runners would have plenty of
velocity to purge any water that would be inducted. The velocity in the
nooks and crannies inside the K-Jet main box (I call it this, for those not
familiar with K-Jet) would not be great, based on the cross section area of
parts of it. You know what happens when a carburettor induction manifold is
badly designed? Fuel separation, uneven combustion etc (carbie V8s now),
sump dilution, bla, bla, bla. You have seen the crap that collects inside
K-Jet's air / fuel reg. with normal driving?

How / where will air / fuel reg be mounted on boat?

At what temp will it operate at?

Under the bonnet, it operates at under bonnet temp, less what ever cooling
effect may come from fresh air, depending on where air is tapped. Remote
mounting on Clair's motor would be an interesting exercise. Check operating
temp of box in the car, then on the boat. This will play a part as to how
quick the thing will rust out. I get paid to come up with quick fixes, we
have a new sports car customer in the US who kicked butt at the opening
Sebring race meeting. We sent them a pile of stuff that we believed would
work on their sports car. Never seen their car. Experience said it would
work and it did. They told us, after the event that they had never gone to
Sebring with such a strong engine. Head temp and associated factors will be
the biggest problem for any future development, as not much more can be
squeezed from their kind of engine. How did we know what we sent them would
help them? This is called "been there done that".

I stand by what I have said, no amount of 250,000 trouble free km over the
road will convince me that K-Jet will function perfectly on water on it's
second trip out.

Try this :
Pull the air cleaner off your Merc. Jam the throttle at 2,500 RPM. Stand
back with a kero cleaning gun with the pick up hose in a 205 litre drum of
salt water. Direct the spray toward the engine and run the experiment for
half an hour. Shut everything down and come back in two weeks. Pull the air
valve box apart and inspect all parts.

The LUCAS throttle bodies on the other hand consist of a butterfly and shaft
and ram tubes if one has opted for tuned length runners. A rev and a squirt
with CRC down each throat would be the sum total of post service required on
our Lucas system, but I think with K-Jet user would always find himself /
herself reaching for his / her tool box.

My previous comments were all about reliability on the water = safety.

If your Merc stopped in a lion park, someone will rescue you, provided you
do not attempt to walk home. If your boat stopped, due to a K-Jet fuel
system failure, you may not be rescued and a swim home, may not be possible.

The pic is not a Lucas system, it is Autronic. The turbos are Garrett ball
bearing
type, which by the way reduces back pressure for a given boost on the same
compressor. This should be a factor to consider, with the on going
discussion
on turbo charging and water injection.

Regards,
Kevin.














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