Date: Fri, 1 Jun 2001 06:31:04 -0800
Reply-To: Mark Keller <kelphoto@ISLANDNET.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mark Keller <kelphoto@ISLANDNET.COM>
Subject: Waterboxer Power vs transplants
Content-Type: text/plain; charset=us-ascii
Thanks to the many responses regarding my question of actual torque and
horsepower of the various alternative power plants vs the waterboxer. I
skipped the TDI because I think it is difficult comparison to fit here.
The engine is very well suited to Syncros according to response to me
and I'd agree.
I searched several sites looking for good data. Most came from:
VolksMotorsports, Dave Marshall, http://www.cobbtuning.com/tech/sohc/,
and Vanagon.com for which I was able to get some useful data regarding
power output in the 3800 RPM range for these engines. I used a fixed
3800 RPM since the automatic van cruises at 65 mph an 3800 RPM.
Therefore this post purports to indicate what amount of power is
actually available when driving at speed.
The basic numbers indicate the horsepower at the crank and wheel for
3800 RPM. I read a good article on Dyno results which essentially says
that +- 5 hp is a pretty tight tolerance, so these numbers can be
argued, but I'm looking at general picture of what to expect.
Engine @3800 Rpm Crank Torque & hp Wheel Torque & hp
Stock 112 ft lb. 82 hp 80 ft lb. 58 hp
Rockers and Chipped 128 ft lb. 94 hp 90 ft lb. 66 hp
Lilly's (low guess) 143 ft lb. 104 100 ft lb. 72.8 hp
Marshall I -4 113 ft lb. 82 hp 80 ft lb. 58 hp
Subaru 2.2 137 ft lb. 100 hp 95.9 ft lb. 70 hp
Subaru 2.5 166 ft lb. 120 hp 116 ft. lb. 84 hp
Subaru flat 6 2,000 ft. lb. 1447 hp 1400 ft lb. 1012 hp
Notes: I used 30% loss per Volks motorsports dyno's. I estimated
Lilly's to be 10 hp more, just on the fact that the chip and rocker dyno
on motorsports doesn't have the headwork or cam, or all the other
modifications . Lilly is probably more but he is at least this in my
opinion. The Subaru is my guess base on torque at 163 ft lb. @ 4400 rpm.
Certainly Ballpark. The six is fantasy.
My thoughts. Well the most surprising thing I came across was the weight
of the Subaru is 262 lb. compared to the 400 lb. of the waterboxer,
which is light. I know the real world difference are probably less than
140 lb., but I actually expected the Subaru engine to weigh more.
Well the waterboxer certainly isn't dead yet. By Putting the Pawter
Rockers on, and setting the timing very carefully and adding a K & N,
you would probably put any waterboxer back into the game for less money
than any other option. The waterboxer dollars start to add for anything
greater, and it's a tough call if a total rebuild in order since so many
intangibles come into play. I'll stab at some intangibles
The waterboxer is a tough reliable engine. Psychologically many are
justifiably weary of it. The problems are really solved, but to bring
your engine into conformance may be to much too bear. Certainly the
power numbers indicate that a corrected waterboxer is good engine among
the other choices.
The inline 4 seem like a good choice for a basic vanagon. It's more
advanced with knock control, I don't known about the weight, with an
iron block, my guess is that it's about the same or marginally the
heaviest among the choices . The power is the same as an un-modified
waterboxer. Personally I'd avoid this engine in a westy if converting.
Why pay the price and not get any more performance. And extra weight,
would actually mean less performance. The Subaru seems best for a West,
less hoses and such, less weight, and at least the same power as a
corrected waterboxer.
The Subaru is an engine that has many strengths and technology on it's
side. My feeling is that it can produce a constant 100 hp. The light
aircraft conversions use the engine at 100 hp constant duty. Looking at
Google search on the engine reveals that the after market is actively
using and modifying this engine in many high performance and
turbocharged areas. If making a war wagon is your speed this is the
motor. These folks are convinced the motor is bulletproof and worthy of
investing their milk money.
Other bit and pieces. I read that the big bore 2.5l has some
compromises to fit into the original chassis, mainly a short stroke, and
questions about reducing headgasket sealing area. The article I read was
on 10 psi Turbo charging it, and they were ok with the issues for what
it's worth. The six is a low production run motor, less than 50,000 in
the years it's been produced.
Thanks for listening.
Sincerely,
Mark Keller
91 Carat
Cowichan Bay, BC