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Old 7th June 2006, 02:28   #16
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Quote:
Originally Posted by Jatt
is there any way by which we can SET the CHarging of TURBO before
it is actually charged.
i.e if the Turbo is charged at 2500RPM, can it be made to charge at 0 RPM
or Atleast less than 2500 RPM??

eg: indigo n Fiesta have 1.4 Turbo Diesel Mills.
-indigo Turbo charges at 2500rpm
n
-Fiesta Turbo charges at 0 rpm
Turbo chargers are engaged at every rpm ...even at 0rpm but the whole function of a turbocharger is to force extra air using the exhaust gases to spin the mechanical turbo fan...hence unless there is enough gas pressure to spool the turbine there isnt any boost provided! It is simple, even if the turbo charger is engaged at 0 rpm it isnt producing any boost coz the turbine is dead at that time...morover for what good reason would anyone require turbo boost at 0 rpm???

JFI: Boost controllers can be used to electonically minimise or increase the boost pressure to the inlet...provided there is enough spooling at the rpm where you want to increase or decrease pressure.
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Old 7th June 2006, 08:33   #17
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Quote:
Originally Posted by byramshroff
This is slightly off topic but its been annoying me for some time--
Lets say for example that the turbo of a skoda RS is set to 1.5 psi of boost and it is increased to 1.8 or even 1.9 psi what detremental effects will this have on the engine?
Its just a question of how long the engine will last.....

Generally speaking, for the same engine if you keep increasing boost, the life will come down.

In extreme cases, the head might blow off, or the piston can crack, overheating problems etc.

In most cases, the engine will start losing compression, and need an overhaul much earlier.

It is very important the engine gets more fuel along with more air at higher boost. If mapping/carburating is not done properly, they can run very lean, and heat sieze.
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Old 8th June 2006, 14:32   #18
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Quote:
Originally Posted by The Wolf
Turbo chargers are engaged at every rpm ...even at 0rpm but the whole function of a turbocharger is to force extra air using the exhaust gases to spin the mechanical turbo fan...hence unless there is enough gas pressure to spool the turbine there isnt any boost provided! .
hence the development of VGTs or Variable Geometry Turbos.

These VGTs change the profile and angle of the vanes depending on the engine speed and load and are controlled by a micro processor.

This will ensure that there is sufficient boost presure even at Low rpms and will eliminate turbo lag.

Already seen in some high end BMWs / Mercs / Audis..
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Old 8th June 2006, 18:14   #19
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Quote:
Originally Posted by epyupc
0 RPM means Engine OFF. Nothing including turbo will spin.

By charging the Turbo, I presume you mean the turbo is spinning and supplying air to the intakes at higher than normal (1atm)
Also by 0 RPM, I think you mean "Idle RPM".

A turbo is nothing but a small fan or "windmill". This 'fan' is placed in the exhaust, and it will spin because of the exhaust air force.
This spinning is used to push more air into the engine intake (using an impeller)

You will notice that at idle the exhaust air will not have enough 'force' to spin the fan.
So it is diverted onto the fan only when it has enough force. This is usually 2000 RPM and upwards.

Generally speaking, the earlier the turbo kicks in, the less boost it can provide. I've never heard of any vehicle that provides boost at idle....
Hi epyupc,

I wasn't aware that turbocharging concept was so simple... But again this raises many questions in my mind.

1. Then why is turbocharging not being a offered in all the diesel cars, atleast these might help the diesel cars to come close to their petrol counterparts as far as performance is concerned.

2. Again in one of the threads I had read that it is better to idle the TC car for sometime atleast before switching off the engine so that the TC unit cools down.... But then how is the idling of engine help in cooling the TC of a car.

Regards
Sumit
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Old 8th June 2006, 20:04   #20
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Yeah, Concepts are always simple .
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Old 8th June 2006, 20:18   #21
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Could add my 2 cents:

1) Turbo charged vehicles tend to have forged internals to handle the additional stresses
2) Turbo spool up is dependent on the size of the exhaust vane and the exhaust volume and velocity. Smaller exhaust vanes tend to spool faster (reduce lag) but tend to give limited amount of boost.
3) Amount of boost produced is controlled by a wastegate (mech , electronic) and max boost is dependent on the turbo size.
4) More boost means more air / oxygen thus will require more fuels else it will run lean and destroy the engine
5) Idling before shutoff on turbo engines is quite mandatory as it allows the high spooling turbo to wind down and not allow the oil to cake on the turbine shaft causing premature failure
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Old 9th June 2006, 09:43   #22
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Guys....
...got this thin in mind about turbo chargin....why not connect an air compressor to the intake....instead of an impeller.....the compressor can run usin a d.c motor or somethin...so that we can control the boost needed which is the main idea....Turbo gurus...some light on this please!!!!
sorry people if its a really stupid idea...
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Old 12th June 2006, 09:45   #23
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Hi Guys,
Excuse me if it is too basic a question.
Is there a gadget to measure the health of the Turbointercooler in my Scorpio CRDE?
Pls advice .
Thnx.
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Old 12th June 2006, 14:45   #24
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Quote:
Originally Posted by angelfire
Guys....
...got this thin in mind about turbo chargin....why not connect an air compressor to the intake....instead of an impeller.....the compressor can run usin a d.c motor or somethin...so that we can control the boost needed which is the main idea....Turbo gurus...some light on this please!!!!
sorry people if its a really stupid idea...
There are a couple of companies selling rip-offs like this on the net. I think the point lies in the amount of boost (and ultimately the power) a D C motor powered air compressor can generate versus the power it consumes for the same.
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Old 22nd June 2006, 17:58   #25
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Psycho has is got all covered but i wud like add a bit more explanation!


PRADEEP KUMAR : Measure the health of an Intercooler?

In simple terms Intercooler is a radiator kinda think and all it does is cools down the intake (charged/compressed) air from the Turbo and direct it into the Intake manifold/header.

Lets the air expand into the Intercooler chamber and cools the charge and thus make it denser before letting in into the engine.

angelfire Jatt
tsk1979 is right!!!
Electric Supercharger/ Turbonator : Its a joke, i mean the electric supercharger. Till now there have been claims but no ultimate product. to generate a boost of 5psi, the electric supercharge must spin at around 20K rpm (a general view) and to make such a device and to power it is really tough.
Turbonator is not a complete joke but it wont provide 35Bhp... Its a vortex generator. The air entering the Device come out of it in a swirl, which will help a proper mixing and combustion in the valve chamber and cylinder respectively. Some aftermarket high end Cold air intakes and High flow intakes have this kinda stuff on it( not the fan but the filter acts like a vortex generator).
Heard that the fan in turbonator has a chance to break and fall of into the intake... do i need to say more.

byramshroff
1.5 to 1.8 psi boost wont do anything.. a decent boost shud be around 3psi onwards.. high end applications have more than 23psi of boost..
epyupc
And Increasing the boost beyond a certain limit on a turbo'ed car will definitely reduce the life span. I am not aware of scoda and not worked on it, but if the boost is electonically controlled and can be modified a small increase of boost pressure will give ur a performance gain and wont hamper ur car. But always make sure u keep and eyes on the engine temperature and related guages.

sumitdongerkery: The cost to do that, and space contraints to an extend is the reason why many diesel enginers arent turboed

Older model turbo's especially in diesel engines needed to be idled before switchin it off. becoz the OIL that run in the bearing(the lubricant inside the turbo) is also unsed as a coolant. So if the vehicle is switched off immediately the flow of oil stops inside the turbo and doesnt have a chance to cool at all. Hence the caking effect, and turbo gets screwed over time.

Now a days u tend to see seperate coolant and lubricant in the turbo. Even water is unsed as a coolant.

w 12

But u shud have added porsche to the list!!!
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Old 22nd June 2006, 19:37   #26
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Quote:
Originally Posted by byramshroff
This is slightly off topic but its been annoying me for some time--
Lets say for example that the turbo of a skoda RS is set to 1.5 psi of boost and it is increased to 1.8 or even 1.9 psi what detremental effects will this have on the engine?
The turbo boost pressure is set based on your engine design and the ability of the mechanical elements to withstand the increase in stress..

if you increase boost pressures without proper knowhow, you will damage the engine..
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Old 22nd June 2006, 19:45   #27
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[quote=general_neo]
Older model turbo's especially in diesel engines needed to be idled before switchin it off. becoz the OIL that run in the bearing(the lubricant inside the turbo) is also unsed as a coolant. So if the vehicle is switched off immediately the flow of oil stops inside the turbo and doesnt have a chance to cool at all. Hence the caking effect, and turbo gets screwed over time.

Now a days u tend to see seperate coolant and lubricant in the turbo. Even water is unsed as a coolant.


Even now it is safer to idle the vehicle for atleast 20 secs before shut off..

The turbine in the TC runs at 200000 RPM and there are chances that the impeller inside the compressor cracks down destroying the TC..
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Old 22nd June 2006, 22:37   #28
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Quote:
Originally Posted by headers
Quote:
Originally Posted by general_neo
Older model turbo's especially in diesel engines needed to be idled before switchin it off. becoz the OIL that run in the bearing(the lubricant inside the turbo) is also unsed as a coolant. So if the vehicle is switched off immediately the flow of oil stops inside the turbo and doesnt have a chance to cool at all. Hence the caking effect, and turbo gets screwed over time.

Now a days u tend to see seperate coolant and lubricant in the turbo. Even water is unsed as a coolant.

Even now it is safer to idle the vehicle for atleast 20 secs before shut off..

The turbine in the TC runs at 200000 RPM and there are chances that the impeller inside the compressor cracks down destroying the TC..

Yes brother!!!

Its always safe to idle ur car for few a min or so before u switch it off... no matter latest technology or older ones!!!!

Last edited by general_neo : 22nd June 2006 at 22:47.
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Old 23rd June 2006, 16:17   #29
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guys... what company are we talkin about????????? we dont like to get misinformed ... i would roll with laughter if someone told me the the turbine spooling @ 0 rpm... with what ??? errrr maybe u whistle into the turbine and you wear your red chaddi outside
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