Modding my ds3 hpi 90 11 plate

[Andrewgilbert93]

Hey guys I've recently brought a citroen ds3 hpi (90)and I'm looking at upgrading a few
parts on it firstly I was looking into getting a remap but was thinking was it worth getting
a decat and upgrading the air filter ? Possibly even getting a bigger turbo fitted (but what turbo??)
Then I was thinking of getting it lowered but what's a safe low ride I was thinking 30mm but then
I'm thinking is that low enough ?? If anyone could point me in the right direction it would be more then grateful !!

[BenS]

Remap is a top option, should pop the 90 up to 120ish.

By decat I assume you mean DPF delete? Just bear in mind it'll fail MOT or any roadside checks by police.

With regards to air filter, Torque7 have made a GSR induction kit for the diesel. Only single figure bhp gains but improves the sound. Alternatively, look into Pipercross or K&N panel filters.

Turbos I'm not too sure about, as it's a diesel and I don't know what options there are about.

Lowering can go up to 40mm I think, but then speed bumps and ramps become an issue. I'd say try adjustable coilovers so you can easily switch ride height.

While you're looking at mods, an exhaust might appeal to you too. Small power gain and whatever kind of noise you want

[Andrewgilbert93]

Thank 's for the reply I would love to be running it as round 130+ ideally.. ow right I heard if I had a dpf it would fail an mot? As I've got it booked in on Tuesday night have to give them a call and double check it
Yeah I've been looking at exhausts just undecided on they type of one I want .. I want something quite loud and sports like.. as for coilovers I've got a pair from my old c3 I was wondering if they would fit on also ??

[BenS]

Yeah without the DPF you'll be chucking a load of particulates and other goodies out the back, and unless you have a garage willing to turn a blind eye to the emissions tests, it will fail spectacularly.

However, if you do remove the DPF you will definitely free up a whole load of power, so if you were to accidentally lose your DPF the day after your MOT and miraculously find it again the week before your next MOT, then chances are you'll get away with it.

[BenS]

Loud exhausts - look at Bastuck or Milltek (although both very expensive). Next step down in price would be Cobra and Scorpion probably, then Powerflow or a custom unbranded one. For maximum noise, lose the centre silencer too, and just keep a small backbox.

If the C3 is the same generation as the DS3, i.e. has the same headlights, then the coilovers should fit as they're the same chassis. Wikipedia has a good article which shows all the cars running on the same platform.

[MrT]

The mot test for diesel is just a smog test not actually an emissions test, so it won't fail, physically if u replace the cat/dpf with a pipe the tester can fail you but if you gut and remove the internals from stock cat/dpf and refit then visually they can not fail you,
Dvla/vosa have claimed to be able to tell on roadside if you have decatted but Yet no news has surfaced of any such equipment being used..

The main thing to remember here is once the cat/dpf is deleted you will have the car remapped to code these out and up the power too, this is now down to the person doing the mapping, if he keeps the fuel trims in check so car doesn't over fuel too much on wot ( wide open throttle) then you shouldn't have too much of a smoke show behind you,
If your car chucks out a load of black smoke then you are likely to be pulled but if it doesn't then it's a very rare chance you get pulled...

[BenS]

I would have thought without the filter to remove the particulates, then regardless of fuel ratios you'd be putting some extent of blackness out the back.

I've heard of people with petrol cars failing MOTs even with high flow cats, I'm surprised the diesel checks aren't very rigorous. Especially after the VW fudge-up!

[MrT]

Petrol cars get an emissions test , testers Rev the bollox of the car while measuring emission, I know this as my mate owns an mot station and all my spare time is spent there tinkering..
Diesel cars emissions test is more of a smog test, probe is inserted into exhaust and engine given a small Rev, that's it, done.
As for the extent of particals, put out by diesel cars after a decat it depends on fuelling, vw cars over fuel like there is no tomorrow, hence the particals and black smog chucked out the back, My bmw 330d has no dpf as it was made before dpfs were made law, and cat has been removed plus car has been remapped, and it barely chucks out any black stuff, not unless I really get on the loud pedal and even then this will only happen once when I push it hard after driving gingerly for a few weeks, once the soot has been chucked out there is no further black stuff , well not at a least for few weeks,
I was having a chat with my mate the maps bmws, about my next stage 2 map and he said with stock injectors if I push the car close to 300 bhp, tho it is achievable the car will chuck out black stuff every time I floor it as injectors will be pushed to almost limit,
However if I get hold of some 335d injectors then I can push the car closer to 340bhp before I see smoke.. Only catch is those damn injectors are around 270 quid plus vat each and I need 6 of the buggers, guess I might get a hybrid turbo instead and push the car to around 320 with stock injectors instead..lol

[Shiro]

The coilovers from a C3 will not fit, different diameter
You bought the wrong diesel for big mods, the HDi 110 has the way better gearbox.

[BenS]

Thanks MrT, that's some good insight into what goes on behind the scenes! I wonder how long it'll be before the diesel testing regulations get made a whole lot stricter...

[monkeynuts]

I have a 115bhp derv and with a Jamie map its doing 150-400 and believe me it pulls like a train

I think if you change things like turbo's etc you could end up spoiling the drive

[MrT]

150 bhp is probably the limit you can get to on stock intercooler as any higher you would be getting a lot of heat soak through the intercooler and lose power.
Yiu will find if you did a few hard power runs back to back the car would feel a bit held back once it gets hot. So a larger intercooler would benefit in the sense that you can sustain boost pressure longer as it dissipates heat better. Also the benefit would be few more horsepower and perhaps a little more lag lower down rev range.
As for changing turbos , on these small engines a hybrid turbo would benefit as it spools quicker but a larger turbo would require more force to turn and hence need engine to work harder to turn. Which pushes power band up but may gain bigger bhp figure ... having said so this is or theoretical as we dont know how much bhp these little engines will make before going pop..
And perhaps what jamie maps these too is safest limit and shouldnt be pushed further unless you have deep pockets.
Changing turbo would change charachter of the car but for good or bad that depends on what route you take.

[MrT]

Just to add. If you do fit a larger intercooler you will need a remap to make use of it..

[pmk]

Additionally if you remove the DPF technically the MOT would be a fail, so if you are involved in an accident your insurance might be invalid.

[MrT]

Additionally if you remove the DPF technically the MOT would be a fail, so if you are involved in an accident your insurance might be invalid.

Agreed. Like any undeclared mod its always a gamble. Insurers can refuse to pay out because of a sticker.. let alone a serious mod.