supercharging a clio

[Scougar]

What charger is that?

(I always wonder why the price of SC's is so high considering the low revolutions and a design that has been used on many many engines (even ship engines) for many many years).

Matthew

[MAXIBOY]

[quote="Scougar"]
4) A reliable gearbox that can take the torque developed by the turbo (which I suspect costs uber amounts, prob more than the engine to get a reliable one).

your having a laff. yet to be developed. even the six grand boxes seam to be unreliable with over 250bhp. mine touch wood has been ok so far.

[stan]

I have already turbo'd an N/A A-Series engine with success.

Matthew

Thats the main problem...people "converting" from an engine designed to run at atmospheric pressure, to one which has + atmos pressure.

doing it properly isnt converting...its designing to be that way...as an eg this means revising crown and chamber design to reduce Cr whilst retainign decent squish...NOT fitting a spacer/thicker head gasket....or randomly skimming pistons.

There are lots of design constraints and considerations...far more than most people care to acklowledge or understand.

[Winston]

Charged F3P

[Scougar]

Thats the main problem...people "converting" from an engine designed to run at atmospheric pressure, to one which has + atmos pressure.

doing it properly isnt converting...its designing to be that way...as an eg this means revising crown and chamber design to reduce Cr whilst retainign decent squish...NOT fitting a spacer/thicker head gasket....or randomly skimming pistons.

There are lots of design constraints and considerations...far more than most people care to acklowledge or understand.

I do realise that I was pointing it out so people don't think I'm talking complete bull. I understand the the likely life span of any n/a engine running 9.65:1 compression ratio and 7psi is likely to be very short. I also understand that using the correct cams, dizzy (Especially important for retarding the advance appropriately) etc must be used.

I would never recommend charging a non-charge designed engine because a most of the time the piston rods etc are not designed to take the additional pressure/stress/heat from forced induction not to mention the higher compression ratio.

Matthew
p.s. did you know that diesel are commonly about 22psi compression ratio, and THEN they decided to turbo them! lol Just goes to show how much better the tolerances are on diesels.

[stan]

whats tolerances got to do with it??

Most std rods are good for alot of cylpressure/torque...its RPM that kills rods.

The reason diesel engines can and do run whomping cylinder pressure, and so produce massive torque output, is because the fuel isnt knock limited. Consequently internal components need to be stronger.

The old AER Le Mans 2.0 engines were Cr= 12.5:1 and ran 2.5bar of boost...just goes to show when its done properly, these parameters arent a problem.

as for dizzy...we have ECU's to control ign/fuelling lol.

[Chris H]

larry widmers dragsters of 20 years ago were running staggered cr's from 16 - 25:1 then the charger ramming in air as well.

A 10:1 cr road car with 7 PSi boost when done correctly will produce long lasting reliable power and have good transient response.

This as Craig pointed out is of no relevance.

All out power is dependant on thermal efficiency and mechanical strength, things like engine capacity, lifspan etc are irrelevant.

Forced induction I would limit to turbos as its a damn sight easier and cheaper, chargers to look right start to require nice bracketry, depending on charger and what form of charge cooling if any is used power can be quite restrictive.

Like Ben said no one is willing to put their hand in their pocket to get it done properly

Winston that charged megane induction tract is nasty! Any specs on it though?

[Winston]

No specs

Think it was in this

[Winston]

Derp

Deffo a megane looking at it lol

EDIT BUTTON

[Scougar]

I just wrote a lot of stuff for you stan, but after writing it, it was a go at you. I rewrote it hopefully more structured and more polite.

TOLERANCE. Are you saying tolerance doesn't matter? I wouldn't like an engine built by you. I guess you wouldn't/don't use calibrated instruments for engine building because tolerance isn't important/has nothing to do with it?

PRESSURE. Causes heat, causes det, causes problems. And i would still never recommend to anyone wanting a reliable engine to run a high C/R and high boost because 7psi is still pretty high on a N/A engine. Plus other components are designed to take the abrupt torque developed by a turbo.

RPM. Yes rpm is a killer which I entirely agree, which is why tolerances are important to get right, as poor tolerance is magnified higher up the rev range. Abrupt force (read: mechanical shock/poorly controlled revolutions) is the killer normally, but can be from things like oil starvation as well.

DIESEL. It is compressed to a very high C/R because it NEEDS to be to get a good burn, not because of knock. I brought up diesels purely as a p.s. Please lets not get into a debate about what can be acheived on a diesel engine, as it was only to say that they run 22psi (ish) and THEN run a turbo. It was a point of interest nothing more

OTHER. Other things to consider are cool fuel being injected can cause thermal shock to hot components in the engine. Airrated oil from an engine not designed to cope with higher revs can cause problems.

DIZZY/ECU. Please tell me what you know about the distributors ignition curve on a metro turbo a-series engine. Thanks to WilliamsClio peeps, I now know that the dizzy position does not effect the renaults, but it was an illustration of importance of picking the right parts. So quite frankly, why did you take the piss?

At the end of this, I am here to attain more knowledge about the clio and hopefully give something back to the club. I am not here to try and show how much of an arrogant prat I am, or how much I know. I don't know everything and can never know everything, just like you Stan. I like to learn, and get better, not try and rip apart peoples discussions.

I'm sure I have rewritten and put a few things wrong because I rushed it at work. Please let me know what charged systems you have built and run personally.

A bit peeved and probably misdirected frustation at Stan,
Matthew