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Topic: 2.5TDi turbo (Read 741 times) |
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derekmiles
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Posts: 3
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2.5TDi turbo
« on: Mar 13th, 2005, 6:07am » |
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I have a great Granada Scorpio TDi 2.5 and it's in top condition.
The turbo comes in at about 2.2k which I understand is about correct.
This means that I have to get into quite high speeds before it (the turbo) becomes useful.
I would like the turbo to kick in at about 1.4 to 1.8K.
Questions;
Can I contact someone at the Ford Technical department about this ?
or....
Does anyone have any advice or information available?
Kind regards to all. Derek Miles.
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LiverpaulH
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Re: 2.5TDi turbo
« Reply #1 on: Mar 14th, 2005, 10:01pm » |
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Derek
You are right it sounds right and is usual for a turbo to kick above 2000rpm rather than before. There are good reasons for this esp as it's better for engines in the long term to run at higher revs than to be laboured below 2,000.
You should consider yourself lucky, i have reached 4750 rpm and the turbo on mine doesn't even stir   .
Time for a visit to the doctor for the car I think  !!
Paul
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Still hankering after a new scorpio- Aus BA Falcon, 5 years later and I still love it!
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richardcoles
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Re: 2.5TDi turbo
« Reply #2 on: Mar 15th, 2005, 3:19pm » |
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Hi Derek,
I read with interest your question regarding 2.5 TDI VM diesels. I have an Scorpio Ghia automatic 2.5 diesel, which I have had for nearly five years, and in all that time I could not tell you when the turbocharger “kicks in”. Further revving the engine up whilst stationary will probably not even lift the boost pressure off zero. What I can say is that if the turbo is not working you will be belching out black smoke, however with the computer sensors it may limit the fuel and thereby not allow excess fuel to be given.
What you are asking to be done by some electronic adjustment is not possible. Turbochargers are as well all know are driven by exhaust gas however the turbo output is not linked to the revolutions of the engine. The turbocharger output is linked to LOAD on the engine. The greater the mass of gas passing through the turbocharger the greater the compressor output i.e. the larger the boost pressure. At low speeds the boost pressure is very low as the mass of gas is low and fuel injected is low, the whole thing is proportional and worked out by the designers on the drawing board however you can change the power output of the turbo charger by changing the nozzle box before the turbine blades and or changing the diffuser ring on the compressor side. As an ex Marine Engineering Chief Superintendent I have done it, but you tread a fine line between improving the performance and causing the turbocharger to “stall” and on large (20,000 bhp) engines this can be a little un-nerving if you are stood alongside it when this phenomenon occurs.
Car engine turbocharger will be a compromise to give power over a wide range of loads whereas marine engine are usually set to give the maximum boost at the top end power. I used to look after a small ship driven by an eight cylinder 2,500 bhp engine running at 600 revs; this engine had no air boost pressure up to 540 revs (about 60% full load power with the ship under weigh) at this time the exhaust temperatures were well over maximum. Then the turbocharger would become “choked” with exhaust gas, as the engine revs were increased further. The boost pressure would then rise from zero to 15 psi within the space of a minute and down would come the exhaust temperatures.
At sea we used to clean our turbochargers i.e. water wash the exhaust side and clean the air side with ACC9 cleaner, both done whilst the ship was under weigh, this would keep the blower working on maximum performance. Remember however that we were burning heavy viscosity fuel (380 cst) whereas our cars burn clean distillate fuel.
I used to have a Ford Serria with a Peugeot 2.3 L un blown engine and it produced 68 bhp. The Granada I had was fitted with a Peugeot 2.5 L blown engine and it produced 95 bhp. The main difference between the two was the acceleration. The power increase through turbo-charging is about 20 to 25%. Marine engines can be blown to increase power by up to 40% however this brings problems at light loads.
Final word, when your turbo stops working you will know as the power will be right down. I would just accept it’s running and ensure you have a clean air filter etc. and leave well alone.
Regards
Richard
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derekmiles
Newbie
I love YaBB 1G - SP1!
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Re: 2.5TDi turbo
« Reply #3 on: Mar 17th, 2005, 6:12pm » |
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Many thanks to Paul and Richard for the in-depth reply.
The information given will be useful to many of the members using a turbo assisted engine.
However, it seem such a pity that when in fifth gear, the boost dosn't come in until a speed of 68 is reached (or thereabouts) !
I must say that I have impressed many with acceleration
when the boost comes in, in the lower gears. It certainly pushes us back in the seats and heads to be forcibly rested on the head restraints.
Again my thanks to both
Derek Miles.
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