boost lag and fuel economy question

[newsh]

How would you check N75 for leaks?

While I wait for MAF hose I will go over PCV system and check the valves and piping again.

Air pressure and soapy water

[hunker7]

Thanks. I will do boost test once I get MAF hose, and I'll check exhaust for blockage in a mean while.

[hunker7]

Cars bad performance is much more noticeable when engine is completely cold. When accelerating car judders ever so slightly.

[hunker7]

So. I have got her running pretty good now, missing about 0.3/0.4 bar. I've boost tested and there are no leaks whatsoever.

Mostly I can feel that something isn't right at higher loads, so I am suspecting middle silencer as it has asbestos in it and it gets all wet.

Rather than opening it up and welding it I am thinking to just replace it with straight pipe.

Before I'm buying pipes and fitting I have 2 questions.

What size is the piping I need, and does the rear silencer have asbestos in it too?

[UrS4boy]

What size is the piping I need, and does the rear silencer have asbestos in it too?

I doubt that there is any asbestos in any of the exhaust components. Asbestos would not have passed TUV requirements in Germany.

Now fiberglass, that is another story, especially based on this photo originally posted by someone here:

BTW - if you are running cats (which you should), they might be clogged.

[hunker7]

On both, A100, and last S4 I opened cats and they were fine, and problem was with the middle silencer, so that's where I want to start.

So both middle and rear boxes have fiber glass in them?

[Vorsprung durch Technik]

Your in for a nice surprise when you get the car up and running well Janis,she should easily do 30 - 31 to the gallon on a run keeping up with the traffic which will include the 50mph roadworks nonsense we all have to endure on the M1.I just got 475 on a whole tank with occasional blast with the display saying 5 miles left.

I'm sure you will get it sorted soon.

[hunker7]

It's very close, I can feel it.

Went to London to see my parents on Friday and she returned 28mpg(tank method).

Leaving London yesterday, I thought I'll drive sensibly at around 60mph and fuel economy wasn't any better than driving at 80mph?

[UrS4boy]

So both middle and rear boxes have fiber glass in them?

Unfortunately my X-ray vision is in the shop on re-call at the moment.

However, based on the photo I posted and experience with aftermarket mufflers ("glasspacks") going back to 1967 (well before you were born ), I would say

"Yes, they both have fibreglass in them. That is the material of choice by most muffler manufacturers, including Leistritz who were probably the OE manufacturers of the UrS exhaust system"

[hunker7]

Thanks Dave!

I'll start making list of parts to delete both mufflers

[Vorsprung durch Technik]

It's very close, I can feel it.

Went to London to see my parents on Friday and she returned 28mpg(tank method).

Leaving London yesterday, I thought I'll drive sensibly at around 60mph and fuel economy wasn't any better than driving at 80mph?

Well thats good considering what i read previously. The 60mph and 80mph thingy sounds about right to me on normal roads going up and downhill.If it were a dead flat for miles you would get better fuel consumption at 60 for sure. About 75 seams to be the most fuel efficient on our roads,less strain on the engine to get up hills as the RPM's can cope with maintaining momentum without altering the timing in the ECU as it would do on load at 60. I just drove mine 800 miles up and down the M1,M6 and M40, 400 thursday and another 400 saturday.I'v actually done over 5,000 miles since i bought her in June.I just love driving it. Coming back from ADI the other week and almost out of fuel i took it extremely easy and got 34 mpg!

Good to hear your getting there.Oh and the engine bay looks awesome!

[Henkjan]

carefull with the fiberglass, wear good breathing protection. fibreglass that has been exposed to high temps is nearly as bad for you as asbestos

[hunker7]

Well thats good considering what i read previously. The 60mph and 80mph thingy sounds about right to me on normal roads going up and downhill.If it were a dead flat for miles you would get better fuel consumption at 60 for sure. About 75 seams to be the most fuel efficient on our roads,less strain on the engine to get up hills as the RPM's can cope with maintaining momentum without altering the timing in the ECU as it would do on load at 60. I just drove mine 800 miles up and down the M1,M6 and M40, 400 thursday and another 400 saturday.I'v actually done over 5,000 miles since i bought her in June.I just love driving it. Coming back from ADI the other week and almost out of fuel i took it extremely easy and got 34 mpg!

Good to hear your getting there.Oh and the engine bay looks awesome!

And you're running some 3 meter wide tyres too right?

I remember getting 32mpg in my old S4, so I'm sure when I fix the issue it'll be fine

carefull with the fiberglass, wear good breathing protection. fibreglass that has been exposed to high temps is nearly as bad for you as asbestos

I don't plan to open them up, just take off and replace with straight pipe

[Vorsprung durch Technik]

And you're running some 3 meter wide tyres too right?

I remember getting 32mpg in my old S4, so I'm sure when I fix the issue it'll be fine

Yeah steam roller tyres Lol. I have never felt so secure in any car than with this one! Awesome cars!

[hunker7]

Yeah steam roller tyres Lol. I have never felt so secure in any car than with this one! Awesome cars!

I am looking at upgrading to 18s at some point with at least 235 tyres, as I feel that would improve handling