Zetec Tuning
There are several versions of the Zetec engine, the 90bhp 1.6 fitted in the Si, the 105bhp 1.8 fitted in the XR2i 16v, and the 130bhp 1.8 that came in the RS1800. The difference between the 105/130bhp 1.8 units are that the 130 has different camshafts and a larger throttle body. It also has a different ECU and oil jet sprays off the main gallery. To buy the parts from Ford will cost over £1000 and for this price there are much better ways to increase power.
Companies like Interpro (01454 412777) and Dunnell Engines (01449 677726), who specialise in Zetec tuning, offer cams and throttle body packages, Interpro's kit consists of fast road cams, an uprated throttle body and a reprogrammed ECU chip. Cost is around £1000. More power than an RST (a standard one anyway...), and no lag!
A good place to start is an exhaust and air filter, panel filters are cheap and can gain a few bhp, much better, for around £50-£100 is an induction kit, a cone shaped filter with induction pipe drawing cold air into the engine. The Zetec is one of the most receptive engines with power gains of 9bhp claimed by K&N, and they also makes a nice induction roar as air is sucked in. Best used together with an exhaust, the air/fuel ratio will need to be altered as the airflow to the engine is increased. K&N are the most popular for around £80, also available from RamAir, Jetex and Pipercross.
Exhaust wise, The Zetec engine is very quiet, which of course is no use at all. Due to the XR2i / RS1800 valence cut-out, tailpipes of up to 100mm / 4" can be fitted, so there's no excuse for anything smaller, although Si's, or cars with different bumpers will need some modification. Magnex (£270) and Scorpion both manufacture systems that fit from the cat back, Scorpion produce a "Group A" full system (£350) with a 2.5" bore that claims power increases of 6bhp. 4" backboxes are available from OMP, Scorpion and Magnex (£100ish).
The normally aspirated Zetec is not that receptive to chipping all that well, RS Turbo, £250 chip = 150bhp, XR2i, £250 chip = 115bhp. More for "driveability" than power, picks up better at lower revs and improves torque. Turboboost offer an EEC-IV/V chip which is cheaper than a superchip though. The Zetec engine is more reliant on the ECU than the CVH, and any modifications such as cams will require the ECU reprogramming to take effect. New to the market is the Unichip, a device that sits along side the Ford ECU and intercepts signals, alters them then passes them onto the engine.
A number of companies produce twin spark plugs that ignite the fuel better, K&N's double platinum's are £7.50 each and Splitfire offer standard for £6 each or platinum at £10 each. Changing the ignition leads can make a difference for a small outlay, Magnacor, Splitfire and K&N all produce them for around £20-£50.
Gas flowing, porting and polishing cylinder heads can release a fair bit of power, but the cost is high, typically around £400 exchange.
Getting a decent increase in power means switching to alternative forms of fuelling, either Carburettors or Throttle Bodies. Carbs are cheaper but difficult to set up and are not particularly smooth when cold. 45mm DCOE's are about £250 each, an inlet manifold (£120), throttle linkage (£50), filter (£80) and fuel pressure regulator (£17) are also required. Burton Power and Dunnell Engines supply complete kits for around £600-£2200 depending on what parts are used. Power gains are around 20-35bhp depending on engine capacity for a standard engine, rising to over 200bhp for a 1.8 with new cams, ported head, modified inlet manifold, Dunnell's own ignition system and high lift valve springs.
The most increasingly popular way to get big power gains on the Zetec is to turbocharge it. There are now more companies than ever producing turbo kits, and the development of the Focus WRC and Cosworth, both of which use Zetec turbo engines, has given tuners a lead to follow. The kits start at £1000 for one based on the T2, which is designed to provide a useful gain with minimal lag. Performance Engine Services' (01162 663833) kit consists of forged low-compression pistons, an uprated head gasket, modified gasket and sump, gas-flowed head, piper cams and a modified turbo housing, cost is around £2500, power around 200bhp.
Engine Transplants
There are several engines that can be fitted into the Fiesta. The most common engine to fit is the Fiesta or Escort CVH Turbo unit, these are cheap and easily available and many tuners cater for them. Newer engines available include the larger Zetecs, the RS2000's I4 and the Duratec V6 from the Mondeo, Cougar and 24v Probe. Cosworth lumps can also be made to fit.
Fiesta Frenzy 400bhp Turbo ZVH Engine
0-60 in less than 4 seconds, 1/4 mile 13 seconds, as featured in Ian Howell's RST, Performance Ford, Aug 1998.
Two litre Zetec SE, DOHC 16v bored to 2.1 litres. Mahle forged, low-compression pistons with Teflon skirts, Carillo con rods with ARP big end bolts, custom-profile Kent FZ1802 cams with vernier pulleys, lightened and balanced clutch, crankshaft and flywheel assembly. Gas-flowed, ported and polished cylinder head with large inlet valves, de-shrouded, knife-edged inlet ports, Raceline inlet manifold and custom ally plenum chamber with integral bell mouths. Jenvey 45mm throttle bodies, reshaped combustion chamber for low compression. Sodium filled exhaust valves with port face adapted to fit S2 Escort RST exhaust manifold, T3.5 hybrid turbo with 360' thrust bearing, Escort Cosworth inlet housing, Volvo (er..) Turbo wastegate housing and Garrett -31 actuator, Bailey Motorsport DV25 dump valve and 0.63AR exhaust housing. (pause for breath...) Pace custom chargecooler, polished cam cover. Weber-Alpha ECU and wiring loom, Bosch 400 blue injectors, 3bar map sensor. Pipercross Sapphire Cosworth cone filter, custom 3" downpipe and exhaust system with Scorpion silencer box and DTM-style twin upswept tail-pipes. Standard five-speed 'box with adjusted gear ratios, AP Racing paddle clutch.
Cost: If you have to ask...
From: Fiesta Frenzy (01522 778787)
Severn Valley Motorsport Zetec Turbo
Produced as a demonstration exercise and fitted to a Ka. The current power output stands at 450bhp, but a nitrous kit is fitted to the car to give 650bhp.
photo (c)1999 www.Auto-eXtreme.com
4-cylinder 1998cc twin cam Zetec 16 valve, 8mm wire-ringed and stress relieved block, lightened and balanced flywheel, ported, polished and gas flowed head, fully counter-balanced crank, high-lift Piper cams and solid lifters, Vernier pulleys, larger cam followers, Mahle forged pistons, H shape steel connecting rods, enlarged inlet valves, RS500 throttle housing, WRC P8 Pectel distributor-less injection system with twin amplifiers, Bosch 400 injectors, SVM custom programmed ECU, twin throttle response units, twin GP A fuel pumps, T35 turbo with 360-degree thrust bearing, pre-turbo oil cooler, Samco silicon hoses, three-port breather system with alloy tanks and braided hoses, Pace GP A intercooler, Pace triple-core alloy chargecooler system, Pace twin-row alloy chargecooler, two gallon scoop tank with twin aftercooler, F1 Teflon chargecooler pipes and fixings, ERL Aquamist water injection system, RamAir induction kit.
From: Severn Valley Motorsport (01952 432139)