Citroen C1, Peugeot 107, 108 & Toyota Aygo Owners Club. (Discount code for CityBugStore: C1OC)

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PostPosted: Fri Mar 08, 2019 4:24 am 
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Joined: Sun Oct 22, 2017 2:56 pm
Posts: 132
Location: Hexham
Drives: 2011 107
Bunkey’s Fast Road/Race Development Diary

Hello all and welcome.

This thread is dedicated to publishing the ongoing progress of the development of my 2011 Peugeot 107 which I formerly used to compete in the Scottish Sprint & Hillclimb Championship.

Its my daily a-b, my work van and my race car.

I will detail the trial-and-error, adventures and competitive attainment of the journey -
Everything from engine modification to switch panels to chassis setup and my personal experience with what works and what doesn't.

I won't claim it to be a definitive guide but hopefully it will serve as a source of inspiration and a base of knowledge for those wishing to get the most from their car. I'll be updating the
thread as I write more - there's quite a lot to cover from the past 2 years. Feel free to subscribe.

Like all good writeups I will of course try to keep it detailed, informative and picture heavy.

A brief history:

I was first introduced to the bug back in 2013 when the #3 rod of my mk5 Fiesta ZS decided to make a swift exit through the side of the block. I needed a cheap runabout and found my
way onto the insurance policy for my family's 2006 Peugeot 107, much to the disgust of my adolescent peers. I hated it. In my ignorance it was a car I had resigned to the realm of
dosy old dears and shopping coupons. It was like driving a cheap tin can. Still, I was stuck with it for the time being and persevered. With the windows cracked and a cloud of smoke in our wake
we toured the twists and turns of the Highland's finest b-roads. To my surprise I slowly grew to love the car – its light weight and humble but revvy 3 cylinder promoted a driving style that
demanded precision and the ability to carry speed through the bends; no modern 'overcompensation' or electronic restriction and all the ingredients for a thrilling back road rodeo if you know how
to tango.. This automotive education continued for a year or two (we even managed the odd track day at Golspie's Littleferry Kart circuit) until I resigned the high-milage motor in favour of
something with a little more tread left.


Part 1 - An Introduction To Motorsport

Early 2017

A few years and several cars later I had become discontent with merely putting in hot laps on Forza and decided I wanted to race for real. At the time I was driving a rather lacklustre Corsa D
with a resale value of £3.5k. Nothing quite offered the honest entertainment of that earlier 107 and I decided to sell the Corsa to secure a budget I could allocate to my racing abition. I found
a clean 2011 Peugeot 107 in blue with 33k miles on the clock; 3door, basic trim and no power-to-weight sapping A/C - possibly the best example in the UK at the time - all for just £2.5k; I took
a bus from the Highlands of Scotland to the bustle of north-east Wales to pick it up.

This left me with a solid £1k to prepare the car for competition.


I had already decided on making my racing debut in the Scottish Sprint & Hillclimb series - Its an accessible route into motorsport at just £70 -ish per round and allows everything from your
standard road car to fully aero'd modifications to single-seaters.
Nothing special required except an MSA Non-Race National 'B' license, at a cost of £43, a helmet and a set of overalls.
You can find more info about the series here:

I would compete in several rounds contributing toward the Speed Championship, which consists of a mix of both Sprint and Hillclimb formats,
opting for the standard road car category: Class A1 for naturally aspirated vehicles up to 1400cc.
There is a definitive set of regulations for racing so at this point in the car's life I tried to make it as competitive as possible within the definition of the rule book
- and of course, my remaining budget.

I began by stripping out anything I didn't need and wasn't required by regulation.
Carpet, insulation, spare wheel, engine bay lining etc.


Compulsory additions were:

-Fire extinguisher
-Visible towing points
-Yellow tape to identify the engine earth cable

I think by this point I was about £500 into the budget - The main offenders being the overalls and helmet.

Being a full 402cc's short of the maximum permissible engine capacity it was never going to hold its own in standard form; the rest of the budget was allocated to improving the competitiveness
of the vehicle.

I started with the intake by ditching the airbox -

Playing around with a mock up system built from 60mm plastic down pipe (similar ID to the throttle body mouth where the airbox attaches); I found this freed up the very top end slightly
and improved the throttle response but the gains were barely noticable and it was tight against the bottom of the scuttle panel which wasn't good considering the engine rocks back and
forth on the mounts under acceleration.

I revised the design and settled on a more compact version using a 62-50mm silicone reducer elbow and 50mm OD 45 degree alloy pipe.
The engine actually responded much better to this system with the same improvement to the top end and throttle response but it also boosted the mid-range torque.


I think, in hindsight, the smaller internal diameter had a similar effect to increasing intake runner length -
If you're interested here's a great write up on the effect intake length has on an engine's power curve: ... th-intake/

In addition to the intake system I made a blanking plate for the old airbox (integral to the cylinder head cover) from 2mm carbon fibre sheet, attaching it with countersunk washers and
2 long bolts which pertrude through holes I drilled in the bottom of the box to wingnuts on the other side - Spring washers are a must as the vibration will cause these to loosen over time.

A breather filter was added to the cylinder head cover where it originally vented back into the airbox - Though I'd probably replace this with a pipe to a small catch tank mounted near the
brake fluid resevoir as I periodically find the top of the cover dirty with oil which has escaped from this filter during 'hard use'.


At this point I took the opportunity to remove the bonnet catch and cable pull for a bit of simplicity/weight saving and replaced these with bonnet pins.
This was a job unto itself - To accommodate the pins where I wanted them I ended up cutting away the inner most bolt location for the headlights and used small clips through the locating
tabs fastening the lights to the bumper instead.


The 'anti rattle bushes' are just small lengths of old rubber coolant hose placed over the pins.

I ran a few 0-62 tests comparing this new induction system to the standard airbox. The premise for these were 3 runs 'there' and 'back' along a flat stretch of road, so a total of 6 runs
for each setup. These were all conducted within a 20 minute time period in calm dry conditions on 13/05/17 which included the time taken to swap out the airbox between setups.

These figures were obtained after stripping some weight from the car and adopting the 'racing start' technique of preloading the clutch slightly at about 4k rpm in first gear then launching off
the handbrake (which is probably a bit more aggressive than the manufacturer's standard 0-60 testing proceedure) but still, I think the published standard 0-60 time of 14.2 seconds is a pretty
conservative figure.

The result as follows:

Standard Airbox

There Back
11.33 11.10
11.19 11.03
11.25 11.08

Average: 11.16sec

50mm Foam filter Induction system

There Back
10.88 10.55
11.08 10.92
10.88 10.64

Average: 10.83sec

Next up I replaced the standard suspension with a budget-friendly set of uprated Koni 'street spec' dampers and 35mm lowering springs.


Its probably worth noting here that stripping weight from the vehicle then using lowering springs intended for the standard car will not yield the advertised 35mm lowering - I ended up
somewhere between the two heights - This will also effectively give you a stiffer-than-advertised platform as there is less mass acting on the spring and damper.

As a very rough guide to the handling characteristics and balance of a vehicle (I may get into more detail later): Stiffening the rear in relation to the front offers more oversteer,
removing more weight from the rear of the car than the front has the same effect. Whilst this improves the turn-in and cornering ability, especially on a standard road car with a 'safety'
level of engineered understeer, there comes a point where you can go too far if you don't compensate with a softer springrate - resulting in unpredictable or snappy behaviour.

Having removed just the carpets, soundproofing and spare wheel at this point; the change resulted in a very nimble package. Contrary to what most people believe about uprated suspension,
the car was also a considerably more comfortable place to be - the higher quality dampers smoothing out bumps and road imperfections much better than the standard items.

The eagle-eyed amongst you may have noticed I also went to the trouble of converting the hubs to use studs instead of the standard bolts (no trouble at all really). I actually snapped up a
set of used OZ Racing wheels on ebay for a very good price before I'd even bought the car. These came from an MX-5 which uses the same bolt pattern as the 107 and fit nicely at 14x6.5j,
offering a jump to 175 or 185 width rubber.


For good practice when converting a bolt hub to studs: Be sure to use stud locking compound and not overtighten them into the hub as, depending on the design, the stud can seat incorrectly
on the angled thread instead of perpendicular to the hub face; creating a mm or two offset in pcd at the other end - Not a problem for wheels but an absolute pain in the tits when trying to fit
a tightly drilled slip on spacer - I had to file the holes in mine to squeeze them on.

Another trick I've found when using slip on spacers, the non-hubcentric type without the ridge on which to centre the wheels, is to use copper grease between mating surfaces and tighten
the wheel nuts in stages (40Nm then 80Nm then 120Nm) with the car completely off the ground (jam the brake pedal with a length of wood between it and the seat if you have to).
This ensures the wheel tightens up properly centred avoiding imbalance vibrations through the steering at anything above 50mph. If you hand tighten the wheels then drop the car to torque
them up - as is standard procedure - you WILL have wheel balance issues. Most garages don't seem to understand this or heed instruction so be aware when you have new tyres fitted...

Which rounds out the budget nicely, give or take a bit:

I had the wheels wrapped in some Nankang NS-2R rubber (bad decision but more on that later) and fit a lovely dished steering wheel courtesy of Driftworks to ice this cake.

Kitted out to minimum specification and with a more purposeful feel to the car I was ready to tackle my first event at Fintray Hillclimb..


To be continued...

Last edited by Bunkey on Mon Jan 11, 2021 10:57 pm, edited 1 time in total.

PostPosted: Fri Mar 08, 2019 6:34 pm 
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Joined: Wed Apr 27, 2011 8:31 pm
Posts: 4768
Location: Motherwell
Drives: Citroën C1
Very interesting read!!!!

Looking forward to seeing more of it :wave:

John - Mechanical Guru :ugeek:
Scottish Area Rep
Citroën C1
Alfa Romeo 159 Turismo Sport
Renault 5 Auto

PostPosted: Fri Mar 08, 2019 7:19 pm 
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Joined: Sun Oct 14, 2012 5:19 pm
Posts: 768
Location: Jersey
Drives: C1 VTR. K11 Micra SR
Fascinating reading! I'm subscribed! :)


Drives C1 VTR 2011

Used to drive C1 Vibe 2007

PostPosted: Sat Mar 09, 2019 12:31 am 
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Joined: Tue Feb 15, 2011 9:02 pm
Posts: 968
Drives: PEUGEOT 107
Great write up, enjoyed that especially the improvised guttering induction kit, good luck with your racing all about having fun with our little bugs, and sure you will do that.

PostPosted: Mon Mar 11, 2019 3:56 pm 
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Joined: Tue Oct 28, 2014 4:13 pm
Posts: 217
Location: Europe
Drives: Citroen C1 1.0 2011
Nice :)
Any plans about chiptuning?

PostPosted: Mon Mar 11, 2019 5:48 pm 
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Joined: Sun Oct 22, 2017 2:56 pm
Posts: 132
Location: Hexham
Drives: 2011 107
james kilowatt wrote:
Nice :)
Any plans about chiptuning?

Yes - I've done quite a bit since the events I've written about here (so far).

I think there are other areas to this engine which would be more beneficial to address first - The inefficient exhaust manifold being one.

I have a set of 42mm individual throttle bodies from a GSXR which I'm planning to fit along with a megasquirt module to take care of ignition & fuelling requirements (I think the standard ecu would be a bit limited in this case).
What I don't have is money so its a case of learning to build everything myself - a welder is on the cards then I'll be able to fabricate an inlet manifold on which to fit the ITB's.

I can't afford to simply remap the standard ECU before this point unfortunately.

I'll be addressing all this in future updates as well as other areas to extract performance so stay tuned ;)

And thanks for the comments guys :wave:

PostPosted: Tue Mar 12, 2019 9:48 am 
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Joined: Tue Oct 28, 2014 4:13 pm
Posts: 217
Location: Europe
Drives: Citroen C1 1.0 2011
For the the exhaust maybe you can find an Italian cecam one - used to for the old "c1 cup". Those cars had standard 90hp using a better air filter, this cecam exhaust and ecu reprogramming. By looking at those hardwares parts my guess is that the exhaust makes indeed most of the difference.

PostPosted: Wed Mar 13, 2019 4:27 am 
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Joined: Sun Oct 22, 2017 2:56 pm
Posts: 132
Location: Hexham
Drives: 2011 107
Part 2

First Impressions

So, having raced to prepare the car, I was just about ready to race on track.

Fintray was probably a good venue to start with; a friendly atmosphere and a simple layout.
Not really knowing what to expect, the day was as much about learning the proceedings as it was trying to put in a competitive time.

The track consisted of a long flat drag to the first corner - a near 180 degree sweeping double apex right hander - climbing through a rounded left hairpin with a tricky exit onto an uphill straight,
then into the tight right final hairpin followed by a short blast to the line.


Beside the passenger ride I was offered by the clerk of the course upon my arrival I had never seen the venue before taking to the track for the morning practice runs.

My driving felt a bit reactive/defensive and I was more focused on trying to locate my braking & turn-in points in preparation for the afternoon's timed runs,
as well as which of the 107's ridiculously long gears I should exit the tight uphill left hander in.

Although the layout was simple there were nuanses to the surface camber & grip, the first corner had a blind entry requiring a lot of commitment and the limit was difficult to judge.
Comparing my practice runs it became quite evident how much time can be won or lost on the brakes. Missing the apex by just a few feet on a slow hairpin results in travelling further with a
considerable addition to overall time.

In short - A lot to take in.

Lunch break offered a bit of respite and I familiarised myself with the competition.
It became apparent that the A1 class wasn't hugely populated, my fellow competitors being a 1010cc Hillman Imp running trumpeted carbs & fat tyres
and a similarly spec'd 1275cc Austin Mini.


Judging by the practice times it was going to be tight and with 2 race runs planned for the afternoon we lined up to see who'd come out on top.
Our fastest of these 2 runs would count as our best score and the winner was the driver with the best score in the category.


In the name of consistency I managed a 39.44 and 39.42 respectively.
The Mini couldn't quite put it together - falling just short of the times,
But the Hillman got the power down, rocketing to first with a decent improvement on practice and seating me in 2nd place of the 3.

It wasn't quite a win but I'd kept on the pace - not bad for a first event.


I had anticipated being a little underpowered and over-geared.
Comparing split times after the event I discovered I was consistently a full 2 seconds down by the end of the opening straight and had clawed back over a second in the subsequent corners
to finish where I did.
This was reassuring of my own performance if not the car.

Considering Fintray a successful first event - I packed up and headed home.


The next 2 weeks saw a basic service consisting of oil & filter change and a set of NGK spark plugs.

On the topic of spark plugs: I see a lot of people mention upgrading their plugs to much costlier Iridium units.
It should be noted that Iridium is not the best in terms of performance - it is much less conductive than copper - These iridium upgrades will last up to 3x as long due to the harder electrode
and are less prone to causing pre-ignition with low-octane fuel (not really an issue in the UK) but do not produce as hot a spark as copper plugs - offering no advantage to outright performance
over their cheaper counterparts.
I would go as far as to say the only real benefit the Iridium plugs offer (in this application) is to the manufacturer who can market them at a high price to an area of the consumer market
competent enough to replace their own plugs but not quite as savvy in understanding the properties thereof.

As for oil, the standard recommendation is ACEA A4/B5 class 5w-30 grade oil.

I tend to use ACEA C3 / 5w-40 oil in the hotter summer months when the car sees more use and ACEA C3 / 5w-30 in winter.
The C3 class oils have better shear resistance over the A/B classes: Basically an oil gets thinner over the course of its life due to the moving components in the engine literally tearing the molecules
apart (shearing) - this is especially true at the high engine speed and operating temperature associated with race use or long distance driving; the C3 class oil maintains its structure under these
conditions, offering better protection and lubrication for the engine. Comparing the 2 classes under real conditions I've noticed the C3 oils retain the 'just serviced', slick, free-revving feel to the
engine for a lot longer than the A/B oils which seem to cook and lose that fresh edge after just a few hundred miles of hard use.

Service complete and feeling a bit more comfortable with experience under the belt from the previous round, it was off to Golspie for my first sprint event.


This round would prove to be a real challenge in terms of putting in a competitive performance.
I was pitted against 4 seasoned drivers in 2 well prepared cars at the upper limit of engine capacity for this class -
On a track with long straights interspersed with slow, tight bends.

Acceleration and straight line speed were the key to fast times here.


We were offered 2 timed practice runs in the morning hours. I'd been to the track a year or so earlier but wasn't sure how I'd fare in competition so wasted no time in trying to find the pace.

Comparing the times at lunch, owing to last second braking and good corner exit speed, I'd managed to keep on terms with the 1389cc Corsa driven by David and Alan Munro in 3rd and 4th place respectively.
My times hovered in the ~95second region for the 2 laps, within a second of their ~94second runs.

The Gordon's 1360cc 205 was in a league of its own...

Practice done, we broke for lunch and unfortunately so did the weather.

The afternoon began on a wet track.

I'd lost the corner entry & exit advantage I previously had in the dry and rather predictably got decimated on the straights, finishing my first race run with a 102.49.

A break in the weather meant the track began to dry out; it looked like a dry second run but it wasn't meant to be. Once again the rain started to pour right as I queued up.
The track was a total wash out in minutes and I wasn't able to improve on my earlier time - Ending the day behind the faster cars but happy with the pace considering.


I'd played around with tyre pressures a bit at this meeting - running around 27psi front / 28psi rear - the front-rear balance resulted in a controllable amount of oversteer midcorner with the lower
pressure offering a slightly more progressive loss of grip at the limit; though it was clear I had to address the acceleration of the car...

Upon my return to base I set about on another course of dieting, removing any remaining weight that was reasonably accessible.
Rear wiper assembly, aerial, non-critical heat shielding, headunit & speakers, as well as the door and bulkhead interior soundproofing -
The latter of which was not the easiest of tasks given the wiring loom, pedal mechanisms and plumbing that pass through it.


I rely on this car daily as my primary mode of transport so I didn't want to commit to the time consuming process of removing and refitting fundamental systems for the sake of a few stray bits of
matted fibre - Instead I set about it with an assortment of blades, removing what I could bit by bit.
The only place left inaccessible was the area behind the heater matrix but I was happy enough with what I'd managed to accomplish.


The various airbags also weigh a lot but I think it would be unwise of me to publicly suggest removing these...

Whilst preparing for the next round - a hillclimb event at Forrestburn - a few more bits arrived at my door: A simple nylon gear knob and a brace for the front subframe.
Nothing game-changing but if there's one thing to learn about when striving for success (at anything in life) its that a collection of small changes can manifest as a big gain.
On that note I think being comfortable and confident within the setup of the vehicle can extract a better real world performance from the combination of car and driver than a slight edge to
mechanical performance on paper.
Or in other words - Ergonomic upgrades can be just as beneficial as performance upgrades.

I started by fitting a pedal extension to the accelerator - The standard configuration has the accelerator set further back from the brake for safety reasons. Adding the extension brought the
accelerator in line with the brake pedal and extended it downward, making it easier to blip the throttle with my heel whilst pressing the brake pedal when downshifting into a bend or getting back on
the power without upsetting the balance of the vehicle. You're probably aware this is called the heel-toe technique.

Having measured the diameter when ordering, I then went to fit my racey gear knob..

Damn. Wrong thread pitch.

The knob itself was a nylon teardrop with a cylindrical threaded metal insert held in place by a single M5 bolt at the top. The insert could be removed and was similar in diameter to the non-threaded
lower part of the gear stick with the rubber sleeve.
With the help of an accomplice I cut the gear stick down to what I deemed an ideal height (removing the standard threaded top portion in the process) and drilled a hole in the top, directly down
the shaft, which we tapped to accept an M5 bolt. Wrapping the covered part of the shaft in electrical tape to create a snug fit, I bolted the (now slip-on) nylon teardrop directly to the gear stick.

What we'd fasioned was essentially a crude short-shifter with about a 20% reduction in throw between gears and slop inherent to the design of the ball-and-socket lever mechanism.

If you're suffering with dry and sloppy lever action (consult your GP...) you can easily remove the gaitor and centre trim to access this ball-and-socket joint and pack it out with a thick grease -
I did this with limited success; wouldn't call it a fix but it gave the gear stick a slightly better feel.

Fitting of the lower strut brace was a comparitively simple task - It bolts between the front most wishbone locations on each side, joining them together and thus stiffening the subframe.
Just follow the instructions and (using a few extension pieces to get access from the front of the car) be sure to torque up the wishbone bolts with the weight on the axle.
The brace I used was the powdercoated steel version from Weicher. It actually performed really well with a marked improvement in steering response. Essentially it removes that split second delay
between turning the steering wheel and the car changing direction (caused by flex in the chassis - An important consideration when using stickier tyres), with an increase in feel for what the front
wheels are doing and where the limit of grip is.
My only gripe with the brace was that it hangs below the exhaust with very little clearance: Since the events detailed here and after a few outings with a passenger on crumbling single track roads,
I'd spanked it off the ground under heavy braking hard and frequent enough to bend it back into the exhaust pipe - This caused it to rub and rattle. I was worried the repeated impacts would
eventually damage or distort the subframe where the brace was mounted so decided to remove it again despite the initial improvement it had made to the handling.

In light of the handling improvement I would like to fabricate a revised design with more ground clearance - I'd be keen to make a few of these in TIG'd stainless steel to cover the cost of a welder
if anyone is interested in purchasing one for their own car.. (PM me)

With the next round looming I was determined to improve on my previous efforts. The course looked a lot more technical - A proper test of driving prowess with an emphasis on cornering ability
rather than engine capacity.

Would these revisions be enough to shake up the results at the highly anticipated Forrestburn Hillclimb?

Stay tuned...


PostPosted: Wed Mar 13, 2019 9:30 am 

Joined: Tue Nov 13, 2018 12:20 pm
Posts: 27
Drives: Toyota Aygo
Following this with great interest!

Im using my Aygo for the Toyota Sprint Series this year, as well as it been my daily drive too

There is 2 of us doing so to be fair in Aygo's

I may go down the Hillclimb/MSA Sprint route at some point too as i have my MSA Licence and all relevant equipment to take part.

If your on Instagram we are at @teamaygoracing

PostPosted: Thu Mar 14, 2019 4:33 pm 

Joined: Mon Jun 22, 2015 5:02 pm
Posts: 91
Drives: 2007 107 Urban 5dr
Brilliant reading....looking forward to the next installment!

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