Date: Tue, 05 Dec 95 14:32:09 CST
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: Joel Walker <JWALKER@ua1vm.ua.edu>
Subject: Road Test 1984 SA Oettinger Microbus
Oettinger Microbus
CAR, June 1984
The big story is a 30 per cent increase in both power and torque.
But the nicest feature is the way it's delivered ...
If we leave aside turbos - now the "in" way of increasing the muscle
power of an engine - the traditional performance conversion involves
pushing the power band up the rev scale, to obtain more top-end zing
at the expense of low speed pulling power. The closer to competition
specs you take the motor, the narrower its power band and the rougher
its character. But, of course, there is another kind of conversion in
which the motor's breathing capacity is stepped up, in conjunction
with its torque, so that its potency is upgraded without distorting
its output curves.
FREEING LATENT POWER
If this type of exercise is carried out skilfully, in conjunction with
a judicious increase in capacity, the power and torque latent in the
basic design are freed to do a bigger job and the fuel consumption
penalty can be minimal - perhaps only applicable when the extra
performance is actually used to do more work than would be possible
with the standard engine.
Such a conversion is offered in the Oettinger Microbus now available
from Lindsay Saker - developed to meet the demands for livelier
performance experienced mainly on the Highveld, where the power loss
associated with altitude makes the standard vehicle significantly more
sluggish than it is at the coast. Priced at plus/minus R18400,
depending on the equipment specified, the Oettinger Microbus conversion
was developed by Oettinger in Germany using their own specialist
components and provides a striking example of what can be achieved,
at a price.
For R19575, for example, you get alloy wheels, a tow bar and a custom
paint job. Our test vehicle had been equipped with two sunroofs:
a (larger) vinyl covered unit located amidships and a smaller,
electrically operated unit in the front section of the vehicle. The
smaller one was made of plexiglass with a trimmed inner panel and its
control button was placed on the dashboard, to the right of the steering
column.
The test vehicle was also fitted with a Sanyo hi-fi and an ultra-sonic
anti-theft system incorporating a remote control unit that we found more
irritating than useful. It embodied three significant improvements
recently introduced by VWSA - a chrome luggage retainer frame similar
to the unit used in some earlier Microbuses, a new grill with twin
halogen headlights and the latest upgraded paintwork, which featured
dark brown in conjunction with cream, highlighted by gold striping.
The big story is the Oettinger engine conversion, which lifts engine
power by an impressive 29,8 per cent from 57 kW at 4600 to 74 kW at
4800 - only 200 revs higher - while boosting torque by 29 per cent
from 141 N.m at 2800 r/min to 182 N.m at 2500 - even lower down the
rev scale.
In short, the Oettinger Microbus boasts a power to mass factor of 51,67
W/kg, compared to the standard vehicle's figure of 39,8. But while the
performance figures are impressive, they tell only half the story. The
really nice thing about the bus is the smooth and balanced manner in
which the extra power is delivered - it is every bit as docile and
tractable as the standard vehicle.
TRACTABILITY TARGET
This was the objective of the tuning exercise, which increased the
capacity of VW's boxer four from 1915 cc to 2120 cc by increasing the
stroke from 68,9 to 76,4 mm, while keeping the bore the same.
Oettinger first made their name as crankshaft specialists and their
Microbus uses a special crank, hand machined from a single billet of
chrome-moly steel and incorporating fully webbed counterbalances.
Special pistons (incorporating similar Heron combustion chambers to
those in the standard engine) lift compression from 8,6 to 9,8:1, and
while valve timing is unchanged, breathing capacity is increased by
employing a high lift cam.
The standard Pierburg twin-choke carburettor is retained, with suitable
jettings, and the lubrication system is given an oil cooler,
thermostatically controlled to "cut in" at 89 degrees C.
Brakes, driveshafts, gearbox and clutch require no changes and the
vehicle's good ride and deft handling characteristics remain the same.
STARTLING IMPROVEMENTS
When we tested the water-cooled 1,9-litre Microbus in our August 1983
issue, the performance improvement recorded over its predessor - powered
by a 2,0-litre air-cooled engine - was quite dramatic. The improvements
now notched up by the 2,1-litre Oettinger vehicle are quite startling,
as shown in the following table:
1,9-litre 2,1-litre
Acceleration (secs): Microbus Oettinger Microbus
0-100 km/h ....................... 22,8 15,34
1 km sprint ...................... 41,0 36,95
Terminal speed (km/h) ............ 115,8 136,8
Top speed (km/h) ................. 131 153
Fuel Consumption (litres/100km):
60 km/h .......................... 7,57 8,14
80 km/h .......................... 8,77 9,07
100 km/h ......................... 10,90 10,66
TEST SUMMARY
So the Oettinger vehicle is much livelier on the road, while consuming
much the same amount of fuel, although when it is driven hard and the
additional kilowatts are being really used, its thirst can be expected
to rise fairly steeply.
Driven fairly hard in mainly suburban usage, the bus recorded 13,4
litres/100km overall. But with a switch to about 50 per cent out-of-town
driving, the consumption fell to 12 litres/100km and this would indicate
a cruising range of well over 700 km.
For the man requiring a really deluxe minibus with luxury equipment,
an impeccable finish and build quality and ample performance, it would
be hard to beat.
Its biggest single attraction is that it retains the balance and
tractability of the original vehicle, while delivering 30 per cent more
power and torque and involving no additional complexity from the
maintenance viewpoint.
Comparable results - possibly even slightly superior - might have been
obtained by developing multi-valve cylinder heads, a technique enjoying
increasing popularity in both Europe and Japan and with which Oettinger
has plenty of experience. This idea was apparently considered for the
Oettinger two-litre Golf GTi, then dropped because of the servicing
complexity it would have introduced.
"Keep it simple" was the preferred route - with everything within the
scope of the ordinary VW mechanic, or capable DIY man. The results
confirm the wisdom of this decision.
SPECIFICATIONS
ENGINE ENGINE OUTPUT
Cylinders .......... four, Max power ISO (kW) ..... 74
horizontally Power peak (r/min) ..... 4800
opposed Max usable (r/min) ..... 5400
Fuel Supply ........ Pierburg Max torque (N.m) ....... 182
twin-choke Torque peak (r/min) .... 2500
downdraught
carburettor
Bore/Stroke ........ 94 / 76,4 mm
Cubic capacity ..... 2120 cc
Compression ratio .. 9,8 to 1 STEERING
Valve gear ......... hydraulic Type ............ rack and pinion
tappets Lock to lock .... 3,75 turns
Ignition ........... coil and Turning circle .. 10,7 metres
distributor
Main bearings ...... four
Fuel requirement ... 98-octane Coast
93-octane Reef
Cooling ............ water, electric fan
TRANSMISSION WHEELS AND TYRES
Forward speeds ..... four Road wheels .... pressed steel
Gearshift .......... floor Rim width ...... 5,5J
Low gear ........... 3,78 to 1 Tyre size ...... 185 SR 14
2nd gear ........... 2,06 to 1 Tyre pressures
3rd gear ........... 1,26 to 1 front ........ 210 to 230 kPa
Top gear ........... 0,85 to 1 rear ......... 260 to 290 kPa
Reverse gear ....... 3,67 to 1
Final drive ........ 4,86 to 1
Drive wheels ....... rear
BRAKES SUSPENSION
Front ............... discs Front ......... independent
Rear ................ drums Type .......... upper & lower
Hydraulics .......... dual circuit wishbones, coils,
Boosting ............ vacuum anti-roll bar
Handbrake position... floor Rear .......... independent
Type .......... diagonal trailing
arms, coils
MEASUREMENTS CAPACITIES
Length overall ...... 4570 mm Seating ...... 8/10
Width overall ....... 1845 mm Fuel tank .... 85 litres
Height overall ...... 1960 mm Luggage trunk .. 1015 cubic dm
Wheelbase ........... 2460 mm Utility space .. 1920-4935 cubic dm
Front track ......... 1570 mm
Rear track .......... 1570 mm WARRANTY:
Ground clearance .... 190 mm 12 months unlimited km.
Licensing mass ...... 1432 kg TEST CAR FROM: Lindsay Saker
KEY FIGURES:
Maximum speed ............. 153 km/h National list price ... R 18 400
1 km sprint ............... 36,95 secs
Fuel tank capacity ........ 85 litres
Litres/100 km at 80 ....... 9,07
Optimum fuel range at 80 .. 937 km
*Fuel index ............... 11,79
Engine revs per km ........ 2092
(* Consumption at 80 plus 30%)
TEST RESULTS: VW MICROBUS OETTINGER CONVERSION
MAXIMUM SPEED (km/h): ACCELERATION (seconds):
True speed ............ 153 0 - 60 ................ 5,98
Speedometer reading ... 168 0 - 80 ................ 10,42
(Average of runs both ways 0 - 100 ............... 15,34
on a level road) 1 km sprint ........... 36,95
Calibration: .. 60 70 80 90 100 Terminal speed ........ 136,8 km/h
True speed: ... 56 65 75 85 94
FUEL CONSUMPTION (l/100km): OVERTAKING ACCELERATION:
60 ................... 8,14 3rd Top
70 ................... 8,48 40 - 60 .... 4,26 9,84
80 ................... 9,07 60 - 80 .... 4,62 7,98
90 ................... 9,80 80 - 100 ... 5,70 8,52
100 .................. 10,66
BRAKING TEST:
>From 100 km/h INTERIOR NOISE LEVELS:
Best stop ............ 3,7 Mech Wind Road
Worst stop ........... 4,71 Idling .... 62 - -
Average .............. 4,15 60 71 - -
(Measured in seconds with stops 80 75 78 87
from true speeds at 30-second 100 79 82 89
intervals on a good Average dBA at 100 ..... 83,3
bitumenised surface) (Measured in decibels, "A" weighting,
averaging runs both ways on a level
road: "mechanical with car closed;
"road" on a coarse road surface.)
GRADIENTS IN GEARS: GEARED SPEEDS (km/h):
Low gear ........... 1 in 2,6 Low gear ....... 31
2nd gear ........... 1 in 3,8 2nd gear ....... 57
3rd gear ........... 1 in 6,89 3rd gear ....... 93
Top gear ........... 1 in 13,4 Top gear ...... 138
(Calculated at engine power peak
- 4800 r/min)
ACCELERATION
GRADIENT ABILITY km/h secs
Low gear ........... 21 per cent Low gear ....... 30 3,0
2nd gear ........... 15 per cent 2nd gear ....... 60 6,0
3rd gear ........... 8 per cent 3rd gear ....... 94 14,0
Top gear ........... 4 per cent Top gear ....... 130 30,0
Max torque ......... 2500 r/min Max. speed: 153 km/h
PERFORMANCE FACTORS TEST CONDITIONS
Power/mass (W/kg) net ...... 51,67 Altitude ...... at sea level
Frontal area (sq m.) ....... 3,62 Weather ....... fine, windless
km/h per 1000 r/min (top) .. 28,68 Fuel used ..... 98-octane
Test car's odometer ... 6291 km
CRUISING AT 100 IMPERIAL DATA
Mech noise level ........... 79 dBA Acceleration (seconds):
0-100 through gears ........ 15,34 secs 0 - 609 mph .......... 14,97
Litres/100 km at 100 ....... 10,66 Maximum speed (mph):
Optimum fuel range at 100 .. 797 km True speed ........... 95,1
Braking from 100 ........... 4,15 secs Fuel Economy (mpg):
Maximum gradient (top) ..... 1 in 9,09 50 mph ............... 31
Speedometer error .......... 6 per cent 60 mph ............... 27,2
over <note: Imperial gallons>
Odometer error ............. 1 per cent
over
Engine r/min at 100 ........ 3487