FAQs: After Market Perfomance Mods Ford Fiesta ST150 XR4

Read Part 1 and Part 2 here.

FAQs relating to our performance exhaust manifold, unichip, Stage 1 Kit and camshafts for the Fiesta ST150 / XR4.

1.  I've got a question about the 4-2-1 manifold for Fiesta ST150. Does it fit without any modifications on the rest of the exhaust? How about the flex pipe in this setup. I saw many other manifolds fitted with one and with this one I do not know how it would not crack over time without one.
Yes our SWR exhaust manifold will fit using the rest of your standard system. It comes with a quality spring loaded knuckle, which is like a flex but better. We found that flex sometimes starts disintegrating inside over time and can starting blocking the exhaust gasses.  We have been using the spring loaded knuckle for many years now with no problems at all.

2.  I have recently been looking at your Stage 1 and 2 tuning kits for the Fiesta ST150.  You suggest a free flow 180mm x 500mm rear silencer and I am currently unable to find a supplier of one. Do you know the manufacturers name for the rear silencer?  As well as this has anyone ever run a Unichip in UK climates as the requirements for the map may differ slightly due to the differing locations.
You don't necessarily need to run a 180mm x 500mm free flow silencer.  Any free flow round or rectangular works.  The bigger the silencer, the quieter it is.  The stock standard system works perfectly.  It's only if you want that last 1 or 2 HP that you need to fit a free flow.  The Unichip is mapped perfectly for any conditions. The ST150's Siemens Ecu has a built in altitude compensator.  I sell kits to customers inland here in South Africa at over 1000m above sea level as well as to customers on the coast, and they work perfectly.

3.  I just bought a Fiesta XR4 recently and upon looking for some performance gains I came across the Stage 1 performance upgrade.  Is there anything I need to also do along with these parts being installed?
You don't need to do anything special.  The kit is easy to fit and you can keep your existing standard exhaust system after the SWR header.

4.  Does the 4-2-1 manifold for the ST150 fit directly to the stock catalyst or does it need to be modified to fit?
It does not fit.  You can fit a Sportcat.

5.  What sort of intake (cold air) do you recommend to suit your Stage 1 kit and can you supply it with the kit?
I don't supply intakes, but what works really well is a cone filter like K&N or Simota.  You fit it to the throttle body using silicone pipe and a couple of clamps.

6.  Your branches look great but would like to confirm the rest of the system.  Once I have bought your front section manifold what would I still need to buy for the rear section?
Seeing as you are at altitude, rather keep the system the standard 54mm right through.  Otherwise you will lose mid to low range torque.  At aĺtitude you lose around 18% power compared to the coast, so going bigger won't help.  The middle resonator is already a free flow unit, so keep that.  You can change rear box to a 180mm dia x 800mm long round free flow unit.  That is the biggest that will fit and not too noisy.  You will only need one cat fooler.  My performance manifold comes with the lambda sensor bung for the oxygen sensor closest to the engine.  You don't need a cat fooler for that.  On the exhaust system after the standard cat there is a lamda sensor bung.  You keep that and screw the cat fooler in there.   You can fit a K&N they are good.  Or a Simota.

7.  I've seen that you have the stage 1 upgrade kit for the ST150.  Ultimately I would prefer to do the stage 2 ST190 upgrade. Is it better to do the stage two when you get stock again or can I do the stage one and then just buy the extras when you get stock? Is the unichip mapping different or is it just the cam that gets added?
You can do stage 1 first. When you fit cams for stage 2 then you can courier your Unichip to us and we have the stage 2 map fitted.

8.  Will the headers come with a new manifold gasket ? I'm assuming if the pipe diameter is the same a standard gasket will do the job?
It doesnt come with a gasket because you can reuse the original gasket.  It is a steel gasket. Yes keep the original diameter of your system, don't go bigger.

9.  Regarding your exhaust manifold for the ST150, will my engine light stay on after fitting? You recommend not increasing the diameter of the exhaust but will a 57mm diameter cause a loss of power as opposed to the stock 54mm?
Yes the engine light will come on. You can fit a cat fooler. A 57mm exhaust is fine you will not lose power. The 54mm gives a little more mid range power and torque especially if you live at altitude where you lose 18% power due to less oxygen.

10.  I've a question about the Unichip installation in the Fiesta ST150.  Is it inside a box (fuse or EMS) in the engine bay or in the cabin somewhere?
The Unichip comes with its own wiring loom which is quite long. The wires get joined to the wires at the back of your cars ECU in the front of the engine bay. Then the loom is brought back through the rubber grommet on the firewall behind the cubby hole. The Unichip is then plugged in. It is nice and cool there. It is easy to fit. It comes with a little bridge plug, so if ever you want to convert your car back to standard, you just unplug the Unichip and plug in the bridge plug and everything is configured back to standard.