Ford Escort Mark IV RS Turbo Series II
Ford RS Turbo Series II

[MK4 Escort Series 2 Turbo Image] [MK4 Escort Series 2 Turbo Image]

[MK4 Escort Series 2 Turbo Image] [MK4 Escort Series 2 Turbo Image]

The RS Turbo Series II car was based on the previous Escort the RS Turbo Series I. The engine was incorporated into the new shape Mark IV Escort, with some small changes to make the car more acceptable to normal road use. Unlike both the RS1600i and RS Turbo Series I this Series II RST was produced in both RHD (Right Hand Drive) and LHD (Left Hand Drive) configurations.

The 1600cc CVH engine and gearbox had the following revisions over the Series I unit:

Even with these various engine improvements, the engine still produced 132 bhp at 5750 rpm (250 rpm lower than the Series I engine.) Similarly the maximum torque of 133 lb/ft was produced at 2750 rpm, again 250 rpm lower.

Suspension changes included:

One of the complaints about the previous Series I RS Turbo was the brakes were underpowered. Hence the brakes were improved for this model. Not only was mechanical Anti-Lock Braking System (ABS) employed both the front and rear brakes were also uprated. The front brakes were now 260mm x 24mm discs, although the rear brakes were retained as drums but enlarged to 229mm x 44mm.

The cast alloy wheels were also re-designed but retained the same size 195/50 x 15 VR low profile tyres on 6J x 15 inch wheels. The standard equipment tyres were either Dunlop D40's or Pirelli P600's.

The car gained colour matched rear spoiler and wheelarch trims. Unlike the previous white only colour the vehicle was now available in:

Both a cosmetic addition and practical one was the twin bonnet louve vents. These helped improve the air flow into the engine compartment and were also a nice styling feature.

Again for this revised RS Turbo, standard equipment included:

Colour coded aerodynamic spoilers front and rear, and side skirts improving the airflow over the vehicle.

Long range driving lights were mounted above the front bumper.

Front Recaro (grey and red fabriced) bucket seats, with adjustable head restraints and extending leg supports.

For 1989 this Series II RS Turbo had some minor changes:

  • The badge became an outline rather than solid text.
  • Front heated screen became standard specification.
  • The trim fabric changed from Daytona to Zolda, which was grey, red and blue.
  • The roof lining went from dark grey to light grey.

    For 1990 this Series II RS Turbo had some minor changes:

    Tilt and Slide FFSR (Factory Fitted Sun Roof), Electric windows and mirrors, Central Locking, Heated Front Screen and Tinted Glass, became standard equipment.

    The rear spoiler was re-designed with the side edges wrapping over. The front spoiler was also re-designed.

    The only options became the Metallic Grey paint, power amplifier and on board fuel computer.

    The Series II RS Turbo was produced until 1991, when the Ford RS Escort Cosworth based on the new shape Mark V Escort replaced it. The Fiesta RS Turbo and Sierra Sapphire 4WD Cosworth were also still in production at this time.

    FORD RS Turbo Series II Tuning Guide

    The RS Turbo is a serious car as a base for tuning. There are a number of simple and not so simple modifications that can be made to increase the power output of the vehicle.

    [Turbo and Actuator Image]

    A standard RS Turbo Series II should run with approximately 8psi of boost pressure. This is the setting at which the wastegate starts to open to allow excess boost pressure to bypass the turbo. By simply uprating the turbo actuator a higher boost pressure can be run as long as this boost pressure does not go above the over boost control sensor setting. The over boost setting depends on which boost control unit the engine is using. The later RS Turbo models allowed a higher boost to be run of about 10.5 psi. The Motorola boost and ignition control unit is located behind the cockpit ventilation intake unit and is to the left of the Bosch injection control unit. It has a single boost pressure sensor pipe leading to it. The control is via a Motorola MC68701 8-bit micro-controller. The later model boost control units have a "hash diamond heart" logo visible on them. These were fitted to the 1990 spec RS Turbos. By fitting a 10.5psi actuator the engine should increase its output at the wheels from 130bhp to around 145bhp. To increase the boost above the default over boost setting the microprocessor settings will need to be modified. A chip is needed to run the boost above the default over boost setting of the boost control unit. There are many different manufacturers of chips: Graham Goode Racing, SuperChips, BBR, Collins Motorsport. With a chip an uprated actuator can be used to allow the wastegate to open later and hence run the turbo at a higher boost pressure. It is normal to run the boost at around 1bar (15psi) but the standard engine can be taken further than this if a higher pressure copper head gasket is used and turbo that can blow higher pressures. The ignition mapping can also be changed by using a new ECU chip in the Motorola ignition and boost control unit. The Motorola unit takes the engine speed, water temperature, air intake temperature and boost pressure as inputs. The output is ignition timing and boost control via the Amal valve. Advanced chip manufacturers also change the Bosch injection parameters. The Bosch electronic control unit is located behind the brake master cylinder on the bulkhead and controls the KE-Jetronic fuel injection system. A setting of 2% CO (carbon monoxide) at tick over is retained. A chipped RST with 15psi of boost will be producing around 165 to 170 bhp at the front wheels. The Amal valve is a crude method of boost control. It operates by diverting boost pressure away from the wastegate actuator and hence can safely increase the turboboost. The valve is fail safe, hence it is powered to divert boost away from the actuator and to the airbox. If power is removed or the wire is broken,the Amal valve will close and all the boost pressure will be passed to the actuator. There are three pipes which attach to the Amal valve, each pipe is identified by a letter on the Amal valve, C(middle) comes from the turbo housing, W(top) goes to the actuator, R(bottom) goes to the airbox. The purpose of the Amal valve is to increase the build up of boost but not allow the overboost control to operate. Hence as boost builds up to a pre-determined level within the boost control ECU the Amal valve will be powered, diverting pressure away for the actuator. When the boost reaches a certain level for engine speed and throttle position (load demand) the boost ECU will remove the power to the Amal valve and the wastegate actuator will be used to control the boost pressure. The operation of the Amal valve will usually result in the boost overshooting the pre-set value of the actuator as the boost initially comes in. The overall steady state condition boost pressure is not affected by the Amal valve for constant engine speed and load. A simple two stage boost control, high and low, can be implemented by using a switch to the Amal valve and stronger actuator. If the Amal valve is powered the turbo will operate in high boost mode, if power is removed the turbo will operate in low boost mode. The Amal valve can be configured for variable boost using a simple mark to space ratio device which can pulse the valve on and off for varying lengths of time. When higher boost pressures are used it might be found that some of the older turbo inlet and exit hoses are not up to the job. The turbo creates a lower than atmosphere pressure as it sucks in the air from the air filter. On older or perished original inlet hoses this can cause the rubber to collapse as the turbo starts to suck harder. This will cause the engine to either produce lower outputs or to cut out until the rubber has opened up again. To solve this problem fit uprated silicon hoses. Make sure when purchasing these they are totally silicon and not just cheaper silicon coated rubber versions. A must for all tuned or non-tuned RS Turbos is a replacement K&N Air Filter The replacement panel filters are a similar price to the standard Ford items and have a longer life. If a replacemnet panel filter is fitted the air box can be cut out to aid air flow. For tuned engines is it better to use a cone type K&N Air Filter 57i with a cold air induction kit. Not only does the cone filter allow a greater air flow but also allows the engine to run a cooler air infeed. Remember the cooler the charge on a turbocharged engine the higher the power output. Typically for every 1 DegC lower the intake charge can be made for a 100bhp turbo-charged engine the output is increased by approximately 1bhp. A must for all highly tuned RST's is a larger intercooler. As described previously the intercooler sits between the turbo air exit and the engine inlet. Its purpose is to cool the compressed air charge before it enters the engine. With higher boost pressures the standard intercooler fails to reduce the temperature of the inlet air sufficiently and becomes a restriction point. Bascially by fitting an uprated intercooler the inlet charge temperature can be reduced allowing the engine to produce more power. Remember the more air you can get into the engine the more fuel you can inject hence the more power you produce. One of the problems with the RS Turbo is the room tuner have to use in the tight engine bay. This does not help to keep the engine cool and adds to the problem of fitting a larger intercooler. A way around the space problem is to replace the air-to-air intercooler with a Pace chargercooler. This relies on a air-to-water radidator which uses its own water feed and small pump to keep the extra air-to-water heat exchanger cool. The RS Turbo has a engine safety feature built into the induction system. A charge temperature sensor monitors the air temperature just before the thottle position sensor, if this increases about the critical point of 68DegC the boost control unit lowers the maximum boost to 3psi. The only way around this feature is to let the engine cool down or get the charge temperature lower by fitting a charge cooler or larger intercooler. It is recommended either Champion C57C or C59C or NGK Competition spark plugs are fitted. The gap on these should be set to 25thou before fitment. Higher boost pressures can actually blow out the spark if the gap is not set correctly. Also ensure the ignition timing is set to 12 degrees BTDC with the vacuum/boost pipe removed from the sensor and blanked. This allows the ECU to run 16 degrees BTDC on vacuum and 8 degrees advance on boost. These parameters are for standard ECU settings. Another simple but not cheap modification is to fit a big bore exhaust. Well known makes are: Magnex, Scorpion and Mongoose. All allow a greater and less restricted exhaust gas flow, with a much improved engine note! Similarly with the K&N Air Filter this allows the engine and turbo to run slightly cooler. Once the above modifications have been made it is recommened to fit an uprated cam. Two well known makes are suitable: Kent or Piper. Both companies make uprated CVH cams designed for the RS Turbo. Also note that the CVH engine is renowned for wearing camshafts at an alrming rate. Hence even a replacement Ford item on a engine with over 50,000 miles would show power improvements. It is common to also to replace the hydraulic lifters at the same time as the camshaft, these can become noisy on older engines. Note the above modifications would take a well setup RS Turbo to a front wheel output of close to a max power of 195bhp. Although a dump valve in itself will not increase power it reduces the effects of turbo lag between gears. When the turbo has fully spun up and is pushing its maximum boost to the engine when the throttle is closed during a gear change the turbo will start to push against a dead end. This causes the turbo impeller to loose revs and spin down. When the next gear is selected and the throttle again opened the turbo will need to spin up to its boost pressure again. By fitting a dump valve the turbo can keep spinning since the valve is releasing the built up pressure to atmosphere. This hence reduces the lag of the turbocharger and allows the power in the next gear to come in much quicker. Note: During very severe driving and higher boost pressure the dead end effect of a closed throttle can cause the turbo impeller to shatter due to the high pressure it creates. Quite often with an uprated engine it becomes apparent that the clutch is not up to the job of transmitting all the new found power to the gearbox. This is even more of a problem of cars with higher mileages and original clutches. It is recommened that a new uprated item is fitted. To achieve over 200bhp the RS Turbo engine requires a higher fuel input. There are two options for this: modified Bosch KE-Jetronic ECU or fifth injector. A fifth injector comes in at higher boost and revs and lets the fuel system supply more petrol to the engine. Make sure the fuel filter is in a good state of repair as an old or blocked filter can restrict the fuel flow to the injector system. When running higher than standard boost levels often a boost gauge is fitted to monitor the boost levels. Nomad Racing can supply a range of gauges and fitting kits including boost pressure, oil and water temperature. [Cutback Turbo Shaft Wheel Image]

    When higher boost pressures are used it is recommended a turbo with a 360 degree thrust bearing is fitted. This allows better lubrication and support for the turbo and hence longevity. A hybrid turbo allows faster turbine spin up and hence reduced turbo lag but at the same time allowing the turbo to hold onto full boost at higher engine speeds. A hybrid turbocharger generally uses a cut-back exhaust shaft wheel. Different compressor wheels and exhaust turbines can be matched to the original turbo housing to achieve higher boost pressures and volumes. Ideally the new turbo needs to be matched to the engine boost and power level required. Hybrid turbochargers can be purchased from: TurboBoost, Turbo Technics Real power hungry tuning fans also tend to fit a water injection system, such as Aquamist. This system injects a spray of water into the inlet of the engine which cools the charge and combustion temperature. For the ultimate hit fit a overbored 1900cc low compression block. All the previous tuning tips have concentrated on squeezing ever more power out of the standard 1600cc engine. Once all other avenues have been explored then why not uprate the standard block to 1900cc? At the same time it is recommended to fit an uprated copper head gasket to allow boost pressures above 15psi. Ideally oil temp should not go over 100 Degree C, but 80 to 90 is ideal for best performance. A temperature of over 130 Degree C spells engine damage. It is the fall in pressure due to the lower viscosity that causes the damage - CVHs need 45 psi ideally and start to blow big ends at about 35 psi or lower under hard use. Hence for tuned RS Turbo's it is best to fit a good quality oil cooler to ensure the temperature and pressure stays within acceptable limits. All good tuning projects also include brakes and suspension improvements. A must for a tuned engine is a uprated braking system. As a minimum it is recommened that fast road brake pads such as Mintex 1144 or the newer developed Ferodo DS2000 are fitted. Better still are drilled and/or slotted front disks. Even better still are larger front disks with uprated Cosworth calipers or AP four pot calipers. A simple mod is to use braided hoses and higher specification DOT4 or DOT5 brake fluid. If the engine is tuned it is also a good idea to uprate the standard suspension components. Running higher boost pressures on a standard suspension setup will really push the car. One of the best modifications is to fit top adjustable Spax dampers with lowered and uprated springs. Any more than 25mm lowering and the ABS system will need adjusting to re-tension the ABS belts. To enhance the handling still further it is best to fit polyurethane or nylon bushes to all suspension components. The original Ford rubber ones will perish and deteriorate over time adding unecessary movement to the suspension components. The front anti-roll bar mounts and Track Control Arm to anti-roll bar bushes are easily replaced and will greatly tighten up the front end. The rear bushes are all harder to replace! Strut braces can be fitted to the front and also rear turretts to stiffen up the body. Be careful of purchasing cheaper items particularly for the front since poorer quality items may not fit very well. Ensure all turbo pipes are routed properly around the front strut brace.

    Here is an example of a tuned RS Turbo Series 2.

    FORD RS Turbo Series II UK price guide (Sterling) 

    
Condition       Excellent   Good    Average

Sterling          6000      4500     3500

Add 500 Sterling for the 90 spec model.

It must be noted that prices have increased in the UK during 1997 and 1998!

    Note: The Series II Turbos where produced on C to H-registration plates in the UK.

    For further details see Vehicle Registration Plate Guide.

    NOTE: For turbo longevity it is recommended that the RS Turbo along with all other turbocharged RS models run with fully synthetic oil. These types of oil give the necessary engine protection for the high temperatures attained in turbocharged vehicles. The following viscosity synthetic oils are recommended: 5w50, 10w40, 15w50, 10w60.

    The RS Turbo Series II was based on the XR3i and standard Escort Mark IV of the time. Further details of which can be found in the Ford Escort 1986 Workshop manual.

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