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Tuning intro
Contents:
This page is provided 'cos I got bored and thought I'd run through a few basics as they were (roughly) taught to me. Please mail me if I've written a crock 'o rubbish again :o)
[tuning? engine swaps???]
The basic principles behind tuning are creating a bigger "bang" from the controlled explosion of the air/fuel mixture in the cylinders.
There are many different ways of doing this, including turbocharging, free-flowing the intake and exhaust systems, and supercharging, to name a couple of broad areas.
Generally, people tend to follow one of three major routes when tuning their engines, at least in Fiestas it seems:
- The first is tuning the existing engine. Putting an airfilter, exhaust, maybe some engine and head work in the mix, maybe with a re-work of the fuelling (for example a larger carb or an ECU remap), giving you a healthy power hike on your own engine which you know runs well.
- The second is to swap the engine for a larger capacity and/or newer engine which starts off with a higher standard power output, for example the CVH turbo or a Zetec. The benefits of this include being the relatively low cost of a complete conversion compared to major tuning work on your existing, smaller engine. The downsides include not always knowing how good the new engine is going to be unless you can hear it running. Maybe you'll move onto stage 3 later on...
- The third route is to junk the old engine, fit a new engine, and tune the nuts off it - turbocharging a normally-aspirated Zetec, for example, or fitting a CVH turbo lump out of an FRST or ERST and then tuning it up well above standard power are common examples with Fords.
[first principles]
No matter which type of category you fall into, you need to take note of the following:
First up, you need to have a good condition engine if you want reliable power. Tuning an engine with, for example, worn rings (smoking all the time), leaks, low compression, or worse a completely sick engine, for example a warped head or cracked block, is pointless. The first step with tuning is to start with a healthy, well maintained engine. Otherwise, it's effectively money down the drain.
This is one of the reasons many people choose to bin their existing engine and, while the engine bay is empty, go up an engine size or two. It's worth remembering that many of the Ford engines were made in differing capacities but the same mounting hardware, for example the 1.0, 1.1 and 1.3 HCS engines are all interchangeable, as are all the series 1 and 2 Zetecs. Likewise the CVH engine was available in 1.1, 1.3, 1.4 and 1.6 variants (I won't mention the 1800 Sierra engine, since it's really no better than the 1600 for stock power, and tuning it is a lot more expensive and a lot less common).
For a variety of reasons, manufacturers don't usually produce their family cars with their engine's best power output at the top of their list. Restrictive exhausts and intake systems sap power in order to maintain driveability, reduce noise and emission levels, and keep costs down. One example of this that springs to mind is the XR2i 16v and RS1800 Fiestas, both of which used the same exhaust despite the 30bhp power hike. This is where free-flowing principles come into operation...
[freeflowing]
I use this term loosely, and I won't go into specific details, since I'm not claiming to be a tuner and many tuning companies have differing opinions on how to get the best power from an engine. Basically, free-flowing is the job of making more air and fuel enter and leave the cylinders, and doing so more quickly, to allow the engine to do more work in the same space of time over a standard engine, in effect producing more power.
Things to consider:
- Bigger is not always better - especially true of n/a exhaust systems, where bore size needs to be a certain calculated amount to release the best combination of torque and power. Whereas a restrictive exhaust may sap top end power and make the engine feel more sluggish, an exhaust with too little backpressure will have poor driveability as it will be gutless lower down the rev range.
- Cone air filters which take air from the engine bay are massively overrated - you can often get the same power hike claimed from a cone filter by fitting a free-flow panel filter and reducing the stock inlet system's restrictions, with the added benefit that you don't suck hot engine air in when town driving. Note that a cold-air feeds which are just a pipe dropped down under the front bumper and pointed roughly in the direction of the filter do practically nothing for cold air supply as the time when they are most needed (i.e. when the car is moving slowly), there is usually not enough airflow to push air up the pipe and into the filter.
- De-catting (catalytic converter removal) - often produces a "revvier" engine by reducing the restrictiveness of the exhaust, but will almost always result in an MOT failure due to emissions. See the n/a Zetec Tuning guide for more information on what to expect if you remove your cat.
- Fuelling - it's important to match any modifications which improve airflow to an increase in fuel supply to the engine - best done with a set-up.
- Cams - aftermarket cams are widely available for most engines and increase engine power by changing how far the valves open, and how long for. Various stages of cam profile are available, ranging from the mild road cam which can often be fitted on it's own with little or no other modofications for a better power curve, right up to wild racing cams which don't produce power until they hit 5,000+rpm and require extensive modifications to the engine to suit. Most road-going cars have cam kits available in a "fast road" profile which are suited to light headwork, and a free-flowed induction and exhaust system.
- Headwork/engine work - a good tuner will be able to grind out excess metal from your engine's intake and exhaust tracts in such a way that the fuel/air mixture flows into the engine far better than the standard design allowed. This, coupled with a well-chosen cam, can produce far more power than any other single modification if done properly. If done badly, you can lose power, which is why it's always a good idea to know basically what you need by asking around, reading tuning books, etc, beforehand.
- Setting everything up - once you have made your modifications, the engine is likely to be having kittens because of the changes in it's fuel/air characteristics. This is usually best sorted with a rolling road setup and, for ECU-managed cars, a custom-mappable management chip which modifies the fuelling and ignition maps. Companies such as Superchips provide off-the-shelf chips which just plug into your ECU and are mapped with certain modifications in mind, but you will almost always find that you can gain more power and driveability from a more expensive custom-mappable chip set up, such as the UniChip.
First route - tuning
For people who go the first route (tuning the existing engine), the basic points above cover most of your options. Off-the-shelf exhaust systems and cam kits coupled with a custom chip or carburrettor set-up on a rolling road can give your engine a good power hike and keep insurance premiums down.
If you own a Zetec, please have a look at Adrian's n/a Zetec Tuning guide.
Second route - engine swaps
Much more fun, and you learn much more without necessarily having to learn how to rebuild an engine. On this site we have a lot of information about what engine you can fit in what. For Fiesta, Ka and Puma owners especially, we have the Fiesta engine conversions guide. This information is also broadly applicable to Escorts and Focus models as well - if it will fit in a Fiesta engine bay, it'll definitely go in an Escort or a Focus!
Third route - big power
This route takes in the best of the first and second categories - you get a better engine than you already have, then you make it even better. Maybe I've made it sound too simple here, since there are people currently working on breaking records with Zetecs, and turbocharging the latest Ford engine, the Duratec, which we will be running an article on very soon ;-)
Our ZVH and Zetec Turbo guides should start you off with some ideas for big power.
| Disclaimer: Please note that the information contained in this article is intended only for guidance purposes and you should always consult an experienced tuner before shelling out your money. |
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Please mail me if you spot an error, omission, or something just plain dodgy. Also take a look at the disclaimer at the bottom of the page :o)
Although every care is taken to avoid errors, neither the site nor myself can be held responsible for any errors or omissions contained on any part of this site.
If you have any queries, good advice from the peeps who have done this before can be had by posting a question on the Fiesta Turbo forums. More information on engine conversions can also be found at Mark Stewart's Fiesta Projects site. |
[links]
Puma Racing general tuning guide
An excellent and far more in-depth study of the tuning information outlined above. If anything written on PumaRacing contradicts what I've written, trust them! :o)
Fiesta engine conversions guide
A run-down of the various engines you can fit in your Fiesta to gain the best power. Information also applicable to Puma and Ka.
Zetec tuning guide
What you can do to gain power from your Zetec, right up to 200+bhp 2.0L tuning.
Zetec turbo guide
What you need to know if you want to turbo your zetec engine.
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