Performance modifications technical discussion.

[Czar]

Now some of you maybe aware, that I do not own/drive a Citroen DS3, so what am I doing on here ?

I have a great deal of involvement in the Automotive and Motorsport sectors, along with engine technology including, GDI, Piezo and laser ignition technology, and currently as I own and drive on a daily basis a BMW MINI that shares this engine, I thought I might be able to offer some pointers, and help all who are willing to learn about performance modifications and the aftermarket products of which you purchase.

I understand that maybe I might be bashing my head against a wall, and that I can't reach out to everybody, however, I am willing to share, if anyone is interested!

[Dangerousfish]

Now some of you maybe aware, that I do not own/drive a Citroen DS3, so what am I doing on here ?

I have a great deal of involvement in the Automotive and Motorsport sectors, along with engine technology including, GDI, Piezo and laser ignition technology, and currently as I own and drive on a daily basis a BMW MINI that shares this engine, I thought I might be able to offer some pointers, and help all who are willing to learn about performance modifications and the aftermarket products of which you purchase.

I understand that maybe I might be bashing my head against a wall, and that I can't reach out to everybody, however, I am willing to share, if anyone is interested!

The post is appreciated

I'm by no means mechanically minded. I can understand the general concept of vehicle mechanics but when we start getting in to the nitty gritty I tend to get lost.

If you've got some time could you shed some light on some of the things you were going to discuss in Nerd's topic? I'm very interested in the Forge intercooler at the moment due to being a massive fan-boy of theirs. Is there anything that I should know about or any recommendations you could make before shelling out for one?

[Czar]

The post is appreciated

I'm by no means mechanically minded. I can understand the general concept of vehicle mechanics but when we start getting in to the nitty gritty I tend to get lost.

If you've got some time could you shed some light on some of the things you were going to discuss in Nerd's topic? I'm very interested in the Forge intercooler at the moment due to being a massive fan-boy of theirs. Is there anything that I should know about or any recommendations you could make before shelling out for one?

Intercooler core structures and assembly techniques vary considerably, companies are generally in business to make profit, and if maximising profit means sourcing cheaper materials and labour, then this is exactly what business ethics some companies take, and although a particular product is aesthetically pleasing (shiny) the performance aspect of the original product has somewhat been compromised to maximise profit!

When a particular intercooler core is produced using the cheapest tube/fin material arrangement and then glue bond the core together, (remembering that glue is a heat thermal barrier) then the intercooler core becomes a heat sink unit and not a heat rejection unit!

And when your paying for a unit to cool your charge air, you want exactly that, don't you ?

[Dangerousfish]

Intercooler core structures and assembly techniques vary considerably, companies are generally in business to make profit, and if maximising profit means sourcing cheaper materials and labour, then this is exactly what business ethics some companies take, and although a particular product is aesthetically pleasing (shiny) the performance aspect of the original product has somewhat been compromised to maximise profit!

When a particular intercooler core is produced using the cheapest tube/fin material arrangement and then glue bond the core together, (remembering that glue is a heat thermal barrier) then the intercooler core becomes a heat sink unit and not a heat rejection unit!

And when your paying for a unit to cool your charge air, you want exactly that, don't you ?

So with the above in mind have you had any poor experiences with any of Forge's products in the past and would you recommend purchasing from elsewhere?

[Dave Clarke]

The Seat Ibizi/Leon Cupra/R intercooler fits with only slight mounting modifications and is considerably cheaper than the dedi DS3 intercooler.

[Czar]

So with the above in mind have you had any poor experiences with any of Forge's products in the past and would you recommend purchasing from elsewhere?

I personally wouldn't give a particular intercooler brand, the slightest consideration, considering how it is constructed, sadly and this happens all to often, aftermarket intercoolers are marketed by so called "performance specialists" as the one to have by advertising lots of X, Y and Z to the uneducated masses who believe everything that particular "performance specialist" company tells them, when in actual realistic fact, the "performance specialist" company know nothing to very little about the very product they are marketing! I can supply a series of questions to ask, and when you ask the particular "performance specialist" the questions, they won't have the answers, simply because they don't know.

Choosing an intercooler that actually works as intended is all about understanding how an intercooler works in the first place, there is lots of talk about pressure drop (psi) the lower the better, however this is a trade off, you either have a very low pressure drop (psi) usually around 0.5psi pressure drop is the general advertised blah blah, and no heat rejection due to the charge air spending so little time in the intercooler, that any chance of a heat rejection process taking place is negligible, that said, the low pressure drop from the difference between the OEM and the aftermarket intercooler, will be felt as an ever so slight increase in turbo boost/spool response, again you can't have the added benefit of the felt ever so slight increase in turbo boost/spool response and have good heat rejection properties, you either have one or the other!

And the more boost pressure you have the more heat you generate, rendering your advertised low pressure drop intercooler from the "performance specialist" useless.

Just as an example, my intercooler for my BMW MINI cost me £3000.00 and you really do get what you pay for.

[Chris_Blue]

Czen- why some people advise against the Iridium spark plugs?
Something bout the spark being blown out?
OEM plugs are recommended
CBLUE

[Czar]

Czen- why some people advise against the Iridium spark plugs?
Something bout the spark being blown out?
OEM plugs are recommended
CBLUE

Have a read of this post No 35: http://ds3club.co.uk/showthread.php?...ht=spark+plugs

It is possible for the spark to be blown out, common causes are: incorrect spark plug choice, worn out/old spark plugs, failing coil over pack, (in our case), plug wires and coil/s, faulty electrical connectors, cylinder pressure spikes from incorrect timing values and increased turbo boost pressures spikes from incorrect re-map value parameters, and poor control of fuelling from incorrect re-map fuel map trim value parameters, etc etc.

[Bigfeet]

Hey Czar, enjoying your thread and the knowledge you're bringing to the club. Wondering if you could answer a question of mine?

On the THP engine could you explain a bit more about the PCV part, it's function and why there are some issues, it's one thing I have not really got my head around.

[Czar]

Hey Czar, enjoying your thread and the knowledge you're bringing to the club. Wondering if you could answer a question of mine?

On the THP engine could you explain a bit more about the PCV part, it's function and why there are some issues, it's one thing I have not really got my head around.

Thank you for your kind words, I will do my best, so here goes:

Here is the cam cover showing the various sections, and the PC valve flap diaphragm's.



Rear PC valve flap diaphragm in it's natural closed positions.


Rear PC valve flap diaphragm, open (this open position is vastly exaggerated, and will not be like this with it's lid on) showing the port passage exit.


Central sprung pressured diverter.


Diverter diaphragm (ignore the damage)


Underside of Diaphragm and pressure control spring.


Diaphragm direction/pressure control valley.


Central valley separation step


Right hand side, PC valve diaphragm flap, in it's natural closed position.


Valve diaphragm flap open, showing the port passage exit.


Firstly let me explain a little about the PCV, PCV is an acronym for Positive crankcase ventilation, inside the the cam cover there are a few entrapment passages and direction chambers, which do their best to separate the suspended oil particles from the passing vapour, this vapour is then vacuum drawn from the cam cover passageways through a valve flap, the first direction is through the rear PCV line into the intake manifold, next, when the vacuum draw from the turbo (building boost pressure) is greater than the vacuum draw of the induction stroke from the pistons, the rear PCV valve flap is closed, as is the diaphragm in the cam cover, this then changes the direction flow of the vapour, and the vapour is vacuum drawn through the passenger side PCV valve flap into the air intake flow pre-turbo, once off boost and steady throttle is resumed then the vapour is once again vacuum drawn through the rear PCV line.

Now the actual valve flaps themselves are merely free falling self closing rubber diaphragms, there is no spring or piston actuation on either valve flap, however there is a sprung chamber diaphragm, which opens/closes under the vacuum draw from both the inlet manifold and turbo vacuum draw, this dictates the flow direction, and in the later re-designed cam cover allows excess pressure to vent through the inbuilt pressure release sprung valve.

Hopefully this should help explain the PCV system, that said the very latest cam cover for the EP6 DT/S engine, has some slight revisions, to the oil mist guide and entrapment valley's, and the PC valve diaphragms are cylindrical free falling, as apposed to the oblong valve diaphragm flaps, in my images.

[gar074]

Top post, czar - many thanks for such a helpful explanation.

[Bigfeet]

Thanks for that Czar, I take it that issues have risen are from too much oil catching in the system?

[cyclone]

Great pics! Hope that was a bad valve cover!

[Czar]

Top post, czar - many thanks for such a helpful explanation.

Thanks for that Czar, I take it that issues have risen are from too much oil catching in the system?

Your welcome, the issue that is the excessive amount of suspended oil particles within the crankcase windage, vacuum drawn from the engines crankcase, into and passing through the camshaft covers particle separation entrapment system, and finding its way via the rear PCV line to the backs of the inlet valves is poor at best, that said, the later camshaft cover (mid 2010 >) with the cylindrical free falling valves, is a welcomed revision over the early oblong free falling valve arrangement.

[Czar]

Great pics! Hope that was a bad valve cover!

Thank you, yes the camshaft cover was from an engine I destroyed in testing.