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TurboZutek

Member Since 27 Apr 2009
Offline Last Active Dec 21 2011 01:43 AM
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Topics I've Started

1.4 Tdci 1500-2000 Rpm... Wobble?

08 January 2011 - 09:23 PM

So, I've noticed something interesting (and irritating) about my MK7 Fiesta 1.4 TDCi, I wonder if anyone has the same;

From 1.5 to 2 kRPM, there's a bit of a judder / wobble in the power output. It's like the car is overfueling / underfueling and the power output isn't nice and smooth. Seems to happen in all conditions. After 2.2kRPM the turbo gets on boost and the power output is fine all the way to the redline.

Car has 17k miles on the clock and is totally unmodified, running BP Diesel. Checked the obvious tyre pressure and wheel balance, of course!

Anyone else had this? Something to flag up at the next service maybe?

Chris...

Tyre Conversion

26 June 2010 - 03:05 PM

So one of the things that sorta annoyed me about my New Fiesta Titanium from day one was its crashing and overly harsh ride quality. It's not the cars fault really, more a poor match of tyres for Scotland's crumbling roads. The factory tyres I'm sure are wonderful on Germany's well maintained Autobahn, but rubbish on Scotland's M8 and A roads. Not only were my teeth starting to suffer after crashing down an uneven and badly maintained road full of potholes, but the rims can actually be damaged too, with one or two chips appearing on the leading edge.

So what to do, given you can never avoid every bad road surface? Well, slightly taller tyres seemed like an idea!

Before:

Posted Image
Fiesta sitting on the factory 195/45 tyres.

After:

Posted Image
Fiesta sitting on new 195/55 tyres.

I had a few reservations, which I'll attempt to address here:

1. Uh, isn't the speedometer out now that you've changed the wheels rolling radius?

Yes, the speedometer always over-reported the speed by 5 MPH, so if I was doing 30 it would read 35. Now it reads 30, so that has actually improved! The speed was checked against my GPS and also on a calibrated kilometre at Kinning Park industrial estate, Glasgow.

2. Does it feel more sluggish now?

Not that I can notice. This was my biggest concern, that I'd loose 'nippyness' for want of a better word, but it's just as quick with the slightly taller tyres.

3. How's the handling?

More or less unchanged - there is the tiny perception of being slightly further off the ground, but really nothing's different. Still grips the road perfectly and doesn't mind being chucked around at all. On less than perfect surfaces the handling is improved, as the car gets knocked off course less.

4. Any unintended consequences?

As the car now sits a little higher, you don't scrape the front airdam on steep inclines or have to slow down quite so much for speed-bumps. Also, these tyres are a lot quieter than the old ones so road noise is reduced a bit too, though that may have nothing to do with the size change. In addition, there is more rubber presented on the side wall of the tyre, hence kerbing is more likely to skiff the tyre than damage the alloy rim now, though I'm very careful to avoid kerbing the wheels anyway.

5. Any bottoming out or arch rubbing?

None found. As a test I filled the car with people, put some weight in the boot and went for a drive - all was fine.

6. So did it actually work?

I would say yes, it has had the intended effect. The ride is FAR more comfortable and hitting rough patches on the road is no longer a ball-breaking experience. The comfort factor is 100% improved.

So yeah, if you find your Titanium is a bit uncomfortable on UK roads, you could do worse than give this a try.

Chris...