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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


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