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Old 26-03-18, 12:15 PM   #1
fritzvis
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Default Engine performance 1Z audi 80 cabriolet

Hi,

This winter I bought an 1Z audi 80 Cabriolet 90pk (1.9 tdi). I gave the engine a good service this winter:
- new oil and filter
- new air filter
- new belts (timing, waterpump belt, alternator belt)
- new radiator
- new waterpump
- new intercooler
- new coolant sensors
- new thermostat
- fresh coolant
...
The car has 185000 miles on the clock.
There is no excessive smoke from exhaust, there are now weird noises from engine... car start's on first turn of key and idles very smooth...
So now I tested it's performance (for what it's worth ) and came to bit of a surprise...
Normally car should reach 60miles/hour at about 14 seconds. It took my car 21 seconds
What could be reason of this loss of performance? It could be turbo, but shouldn't there be a lot of smoke from the exhaust? EGR valve? Injectors? ... Any toughts are welcome before I start breaking down the engine... How can I check different componants for malfunction? thanks for all the help...

Last edited by fritzvis; 26-03-18 at 12:21 PM.
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Old 26-03-18, 04:56 PM   #2
spink
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fuel pump timing checked?
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Old 26-03-18, 05:19 PM   #3
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Inlet manifold can get restrictive due to build up of crap?
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Old 26-03-18, 05:24 PM   #4
fritzvis
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Inlet manifold can get restrictive due to build up of crap?
Due to EGR valve? Is it a lot of work to disassemble and check/clean if needed?
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Old 26-03-18, 05:39 PM   #5
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Do a pressure test on the turbo output under boost with an accurate gauge.
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Old 26-03-18, 05:39 PM   #6
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Quote:
Originally Posted by fritzvis View Post
Due to EGR valve? Is it a lot of work to disassemble and check/clean if needed?
I'm not sure, but the tdi I owned before was noticeably better than the one I have now. The previous owner of the first one had replaced the manifold with a spare one he had "de-gunked".
I need to give mine some love and this is one of the jobs to do!
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Old 26-03-18, 05:43 PM   #7
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Quote:
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What could be reason of this loss of performance?
How about chance that gasket between steering wheel and drivers seat is suboptimal for the car in question? I, for example, am quite sure I won't get out 8 seconds out of my golf, despite it should be capable of that - simply because I'm not drag racer and I don't know what is the optimal acceleration profile for it.
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Old 26-03-18, 05:46 PM   #8
fritzvis
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Quote:
Originally Posted by msh View Post
How about chance that gasket between steering wheel and drivers seat is suboptimal for the car in question? I, for example, am quite sure I won't get out 8 seconds out of my golf, despite it should be capable of that - simply because I'm not drag racer and I don't know what is the optimal acceleration profile for it.
A 7 second difference I'm a licenced rally driver... that doesn't make me quick... but 7 seconds
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Old 26-03-18, 08:31 PM   #9
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7 second difference here is just 50% increase in time; something like if I would clock my golf at 12 seconds instead of 8.

I've seen videos of how diesel fans accelerate in their cars in drag race - I don't know about you but I'm not sure if I would like to do something like that - first, roaring engine at high rpm at start, then start with spinning tyres, then acceleration with shift points @ 4k or above. Did you tried your acceleration like that?

If you really care about performance of your engine, I would suggest you to see how much boost does it have and/or put it on dyno.
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Old 27-03-18, 05:08 AM   #10
fritzvis
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Quote:
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7 second difference here is just 50% increase in time; something like if I would clock my golf at 12 seconds instead of 8.

I've seen videos of how diesel fans accelerate in their cars in drag race - I don't know about you but I'm not sure if I would like to do something like that - first, roaring engine at high rpm at start, then start with spinning tyres, then acceleration with shift points @ 4k or above. Did you tried your acceleration like that?

If you really care about performance of your engine, I would suggest you to see how much boost does it have and/or put it on dyno.
That's true I did it a more gentleman's way but still a 50% difference is questionable... I think it's a good thing to check boost and EGR...
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