New exhaust

Hooversquirrel

Hooversquirrel

Dedicated Member
Joined
Jul 31, 2018
Points
29
Location
Oxford
Model of Z
Z3 2.8
Recently had a new stainless steel exhaust fitted to my pre-facelift 2.8.
The OEM 20+ years old back-box was finished and the Cat and midsection was a cheapo replacement ‘ to get me back on the road’.
Opted for a high flow Cat in the, perhaps mis guided fear, that it would be more likely to pass emissions after reading various stories that cheap non OEM Cats often struggle to pass emissions test.
I really don’t like the sound of the exhaust, but realise that there’s little that can be done about that now. The other thing that’s disappointing is how the new exhaust has changed the power delivery of the car. Anything other than very cautious application of the right foot results in a disappointing ‘take off’ and it’s only once it’s above 2.5-3k rpm that it starts to become more ‘normal’.
Can I get it tuned/ re-mapped ( not that I really understand what this means!) to smooth out the power more evenly across the rpm range?
 
Engine set-up and exhausts are not really my forte. But I have to say it seems very surprising a new exhaust would have such a severe impact.

How many miles have you done in it with the new exhaust? I'm wondering if what's actually happened is the DME has adjusted it's adaptations (tuning) to try and compensate for the ropey old exhaust. And it's not yet reset itself for the new exhaust and the feedback it's getting from the O2 sensors. You can reset the adaptations manually with INPA or it will do it itself but not immediately, not sure how quick, might be anything between say 10 and 100 miles.

I'd also read the codes off in case you had some existing issues which have been brought to the fore by the new exhaust. Or indeed any new errors which might just have been triggered by the new exhaust.
 
If the exhaust was from a stainless steel exhaust centre couldn't you go back to them to see if they could change the sound and check the issues you are experiencing ?
 
Thanks for the replies.
The exhaust was fabricated and fitted by MIJ Exhausts in Wallsall rather than being an off the shelf item.
Since it was fitted it’s done approx 60 miles so perhaps/ hopefully I’ll find a change once it’s done a few more miles...
Encouraging to hear adaptions could be reset if it doesn’t reset itself with time.
Unfortunately I don’t have a code reader but even if I did, would I expect to find any if there is no warning light showing on the dashboard?
 
@ Bampz hummm, I did ask for it to be ‘as quiet as possible’ and was told that this was impossible as these are performance exhausts and achieving a sound akin to OEM was just not possible ( not that I had it replaced for reasons of improved performance) I was told that with time it would quite down somewhat once it had done a few hundred miles....we’ll see!
 
Yes, you may get something of relevance without the engine light. For instance if the DISA valve was knackered that wouldn't throw the light. And the DME has a 'developing' fault status it keeps to itself until the fault has been noted x times before logging fully and turning the dash light on.

A code reader is a good investment for any Z3 owner. This is a popular one. You will need to buy a round 20-pin adaptor and plug into the bonnet connector if you want the full range of codes. But engine codes can be read from the under dash connector as supplied.

https://www.amazon.co.uk/MAOZUA-Latest-Creator-Diagnostic-Compatible/dp/B011KMS2VA

The code reader is good to have anyway. But of course you may find no codes and you may find you're engine is 100%. It's just what springs to mind to look at but it could as yet be nothing other than the exhaust itself or mistake in installation.
 
mrscalex said:
Yes, you may get something of relevance without the engine light. For instance if the DISA valve was knackered that wouldn't throw the light. And the DME has a 'developing' fault status it keeps to itself until the fault has been noted x times before logging fully and turning the dash light on.

A code reader is a good investment for any Z3 owner. This is a popular one. You will need to buy a round 20-pin adaptor and plug into the bonnet connector if you want the full range of codes. But engine codes can be read from the under dash connector as supplied.

https://www.amazon.co.uk/MAOZUA-Latest-Creator-Diagnostic-Compatible/dp/B011KMS2VA

The code reader is good to have anyway. But of course you may find no codes and you may find you're engine is 100%. It's just what springs to mind to look at but it could as yet be nothing other than the exhaust itself or mistake in installation.
Click to expand...
Does that code reader work on 2.8 prefacelift Robert, if so I would be interested in one as the BMW scanner is pretty useless
 
Sean d said:
Does that code reader work on 2.8 prefacelift Robert, if so I would be interested in one as the BMW scanner is pretty useless
Click to expand...
I'm pretty certain it's acknowledged that earlier pre-facelift cars have some issues with most types of reader, hand-held, INPA or BMW Scanner. I've only become aware of that recently. But I struggle for a definitive position on this as I've never worked on early cars. My experience is all later pre-facelift and facelift.
 
Sean d said:
Does that code reader work on 2.8 prefacelift Robert, if so I would be interested in one as the BMW scanner is pretty useless
Click to expand...

They don't work on my cars Sean. I bought one a few years back and found they only do partial reads on pre facelift cars.

I bought a Foxwell NT520 Pro and it works great. Mine cost me £150 from Foxwell. They have uk sellers but the uk price is nearer £180 but they say they offer personal product support.
 
We get diagnostic questions and queries quite regular and may be we could have a "diagnostics / diagnostics tools" section on the forum so that help is easier to find? @GazHyde
 
Jack Ratt said:
We get diagnostic questions and queries quite regular and may be we could have a "diagnostics / diagnostics tools" section on the forum so that help is easier to find? @GazHyde
Click to expand...
We already have what I feel to be too many forum sections as it is @Jack Ratt, but I'm always happy to sticky any really useful threads.
 
mrscalex said:
Engine set-up and exhausts are not really my forte. But I have to say it seems very surprising a new exhaust would have such a severe impact.

How many miles have you done in it with the new exhaust? I'm wondering if what's actually happened is the DME has adjusted it's adaptations (tuning) to try and compensate for the ropey old exhaust. And it's not yet reset itself for the new exhaust and the feedback it's getting from the O2 sensors. You can reset the adaptations manually with INPA or it will do it itself but not immediately, not sure how quick, might be anything between say 10 and 100 miles.

I'd also read the codes off in case you had some existing issues which have been brought to the fore by the new exhaust. Or indeed any new errors which might just have been triggered by the new exhaust.
Click to expand...

Think your theory was right, now that I’ve done another 150 miles things have gradually improved, I’m a lot happier now!
 
You must log in or register to reply here.
Back
Top