DS3 155 I like to change to about 270hp

[Jamie@SPTuning]

Czar, the larger valves you ran. Did you just have to re machine the existing valve seat or did you change them?

[Superfly Guy]

270 is not a small number, so not your average DS3 driver.

Its an infinesimally small number in comparison to car ownership, even to car owners who have or are thinking of increasing the performance of their cars.

Absolutely no difference to overclocking a computer component, and extra 1ghz is achievable in 20 seconds in the BIOS, an extra 500mhz on top of that takes skill and normally an outlay in £££££, cars are no different and the reason the vast majority opt for a map then maybe an exhaust or air filter. Unfortunately the days of swapping out webber carbs and Escort gearboxes are long gone for all but the extremely dedicated (or retired), for the rest of us, its a map.

Saying all that, I am looking at what to do with my car next, not this time I'm home as ive just spent an inordinate amount of money on a new house, maybe back end of summer will see some lower and stiffer springs and something else with the engine.

[Czar]

Lets hope the pistons hold up- specially number 4 (Was it?)

Cylinder piston 3 was the one that generally failed, this was and is due to the valve phase timing overlap, and the very short siamesed exhaust runner of the exhaust manifold, this elevated the cylinder temperature, which caused pre ignition (knock) in this particular cylinder, and once you get pre ignition from elevated cylinder temperatures and carbon deposit, this will and does result in uncontrollable mixture detonation at the wring time, which leads to in excess of 12 tonnes explosive pressure on the piston multiple times at the wrong times, results in catastrophic piston load stress and failure.

Czar, the larger valves you ran. Did you just have to re machine the existing valve seat or did you change them?

I removed the seat completely, machined a new increased seat size, fit new seats, to accept the oversized valves, and then opened up the throats, extensively.

[Superfly Guy]

So at what point do more robust pistons (and associated components) become a requirement on a tuned THP engine if the ECU program parameter map is sound. When I say point I'm talking a bhp bracket, or is it not quantifiable in that way?

[Czar]

So at what point do more robust pistons (and associated components) become a requirement on a tuned THP engine if the ECU program parameter map is sound. When I say point I'm talking a bhp bracket, or is it not quantifiable in that way?

There is no definitive power output level to which point internal components fail, it's controlling the detonation of the fuel/air mixture at the critical moment which is paramount, sadly with the THP engine and the poor controlling and the amount and speed of which carbon deposit build up happens, the THP engine will suffer from knock, which is detected and recorded as misfires, which is pre ignition of the fuel/air mixture from the carbon deposits retaining huge amounts of heat and continuously glowing almost White hot (picture a blacksmiths furnace) only in miniature, this is what you have, and why pre ignition (knock) destroys the Pistons at will.

Remove the carbon deposit, you remove all pre ignition issues, and the Pistons will live very happily even at elevated power levels, that said, the more power you produce, the increase in cylinder pressures raises, significantly, and this can also lead to pre ignition from the resulting increase in cylinder temperatures, a typical firing cylinder temperature is approximately 650°c this rises to a working exhaust temperature of between 850° -950°c when on boost, and the greater the boost levels, you shouldn't be surprised to see exhaust gas temperatures exceed 1000°c this will now start to give the factory stock Pistons a bit of a hard time, at which point failure should NOT come as a surprise from extreme uncontrollable knock or super knock, as the ECU parameter maps for air pressure, temperature, engine temperature, fuel injection pulse cycles per stroke, and retardation of timing, have NO calculated values for these extremes, and try as the ECU does to control the fuel and timing, one thing it can't do, is control the now elevated cylinder pressures and temperatures from excess turbo boost pressure.

When you compress air it generates heat, so therefore more power = more heat, heat is an engine killer if uncontrolled.

[Superfly Guy]

When you compress air it generates heat, so therefore more power = more heat, heat is an engine killer if uncontrolled.

Cue a larger intercooler.

Nicely explained, thanks.

[Ulrix]

Close finish

Now is most items mounted. Forge intercooler and dump valve, Cobra full flow cat and 2,5" exhaust, a DS3R turbo with bigger kompressor turbin and 2steps water/metanol injection from Devil. Runs realy nice but waiting for the remap.....

Have problem when I like to upload foto so sorry no nice pics.......
Check exhaust at https://www.facebook.com/Ulrix.SE/po...58420590850485
Check water injektion mounted in front of left frontwheel + Intercooler at https://www.facebook.com/Ulrix.SE/po...57499117609299

[Ulrix]

I bought this because it is only cab for hole family, 5 persons.

[albish]

Nice work Ulrix, I am still waiting for my water/meth injection, went for AEM V2 tho... Where u getting it remapped?

[Jamie@SPTuning]

Look forward to the results

[Shiro]

The engine has never ever been any kind of hybrid, nor has the Citroen DS3 Racing THP come fitted with the KO4 turbocharger from the factory, the factory standard chosen turbocharger was the KO3

So my turbo is lying to me?
KKK 5304

[Jamie@SPTuning]

Sure the turbo you have is from a racing???

[Shiro]

Was sold as a Racing Turbo :rolleyes:
Strange :confused: