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2008 BMW 130i Manual
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194 Posts
Discussion Starter #1
Car has been running fine since i got it a couple of months ago, but this weekend after a long drive to wales, it starting making a slight knocking sounds when accellerating above 4k revs in 1st and second gears.

Any ideas what this could be? Bad batch of fuel?

The car is going in for an ECUtek remap on friday as i am pretty sure it doesn't yet have a UK fuel map. Would this contribute to knocking?

Any other ideas?
 

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Registered
2008 GRB 20th anniversary 6 MT
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6,572 Posts
Do you mean pinking? (sp?)
 

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Registered
2008 BMW 130i Manual
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194 Posts
Discussion Starter #3
No, its not like the high pitched pinking/chirping sound that i've heard before in cars. This is more like a faint knocking/tapping.
 

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2008 BMW 130i Manual
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194 Posts
Discussion Starter #5
Difficult to say. Sounds like something internal in the engine/drivetrain as its more of a dull knocking rather than distinct. Gets proportionally louder the more you press on. Doesn't seem to do it when the engine isn't under load tho. I don't really want to push it too much to investigate further in case something is causing damage!

Car idles perfectly and until you accelerate hard it runs like dream at cruise on the motorway so i'm a bit stumped.
 

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Mad Englishman.
MY06 Forester STi 6MT
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4,157 Posts
Difficult to say. Sounds like something internal in the engine/drivetrain as its more of a dull knocking rather than distinct. Gets proportionally louder the more you press on. Doesn't seem to do it when the engine isn't under load tho. I don't really want to push it too much to investigate further in case something is causing damage!

Car idles perfectly and until you accelerate hard it runs like dream at cruise on the motorway so i'm a bit stumped.
So definitely
a) from the front..?
b) not from the suspension..?
c) only when going in a straight line..?
c) happens regardless of whether car is hot or cold...?

Probs a dumb question, but have you checked the oil...?
 

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Registered
2008 BMW 130i Manual
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194 Posts
Discussion Starter #7
So definitely
a) from the front..?
b) not from the suspension..?
c) only when going in a straight line..?
c) happens regardless of whether car is hot or cold...?

Probs a dumb question, but have you checked the oil...?
a) yes
b) no, i'd say it was definitely related to drivetrain
c) haven't traied accellerating hard round a corner yet
d) haven't tried accellerating hard from cold, always been fully up to temperature before pressing on. If anything, maybe worse the hotter the car is.

Oil level is fine, but double checked after i first heard the knock.
 

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2004 Forester Sti 6 MT
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723 Posts
I'm guessing transmission or suspension. Pretty difficult to troubleshoot these over the web as location, type of sound, volume all lead to different conclusions. Suggest you take it to a decent specialist if you are worried. Doubt it is the engine pre detonating as I assume you run it on Vpower or equivalent?

Seems we posted at the same time...I would just take it easy until you find the cause. Assume it happens only under Wide Open Throttle not just partial acceleration?
 

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Registered
2008 BMW 130i Manual
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194 Posts
Discussion Starter #9
I'm guessing transmission or suspension. Pretty difficult to troubleshoot these over the web as location, type of sound, volume all lead to different conclusions. Suggest you take it to a decent specialist if you are worried. Doubt it is the engine pre detonating as I assume you run it on Vpower or equivalent?

Seems we posted at the same time...I would just take it easy until you find the cause. Assume it happens only under Wide Open Throttle not just partial acceleration?
I appreciate its not easy to diagnose, my main concern is that its something that wasn't present before and as i've not changed anything on the car i'm hoping its not something serious in the engine.

Was really just wondering if anyone else had heard of anything similar.

Its not just under wide open throttle, it seems to occur whether i'm accellerating enthusiastically or gently once it hits about 4000rpm.

Anyone recommend a good specialist that i can get to from north London?

Cheers guys, appreicate the advice.
 

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2008 GRB 20th anniversary 6 MT
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6,572 Posts
Don't know of anyone in London but Bulldog Subaru at Twyford are well respected.
You'd probably need 1h to get there though.
 

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Mad Englishman.
MY06 Forester STi 6MT
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4,157 Posts
Both Charlie & Simon @ SRR will let you know if it's something to be concerned about on Friday matey before they start anything. Both are experts at noises - especially the wrong kind. They won't run it if there's the slightest concern don't worry.

If you're still going I'll pop along too. :biggrin:

If you're down this way try Dan @ Surrey Subaru Specialists, or Stew at TFS Racing. Both will give you a pretty good idea of whether it's anything to be worries about matey, and both are VERY familiar with Foresters !!
If you like I'll see if either is around to pop over to SRR while you're there.
 

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2004 Forester Sti 6 MT
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723 Posts
Both Charlie & Simon @ SRR will let you know if it's something to be concerned about on Friday matey before they start anything. Both are experts at noises - especially the wrong kind. They won't run it if there's the slightest concern don't worry.

If you're still going I'll pop along too. :biggrin:

If you're down this way try Dan @ Surrey Subaru Specialists, or Stew at TFS Racing. Both will give you a pretty good idea of whether it's anything to be worries about matey, and both are VERY familiar with Foresters !!
If you like I'll see if either is around to pop over to SRR while you're there.

If you are going over to SRR and you have an appointment with JGM then there's your answer! I expect these guys have seen and experienced more on these cars than almost anyone.
As an aside, I asked Bulldog Twyford to check out a clunk when I took it for a service. They confirmed that 'Yes there is a clunk!' but had no idea what it was. Fixed it myself in the end by putting a bit more preload on the coilovers.
 

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Mad Englishman.
MY06 Forester STi 6MT
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4,157 Posts
Just got back - a very good afternoon. Nice of Don to pop over too, and good to meet you Ben.

I'll let you break the good news.

:biggrin:
 

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Don, King of the parts diagram
MY11 WRX STi Sedan 6MT
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5,886 Posts
A nice little mini meet. :biggrin:

Ben, the wait was worth it I would think.

Was it an interesting drive home?
 

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2008 BMW 130i Manual
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194 Posts
Discussion Starter #18
Cheers guys, good to meet you both and lots of knowledgeable advice.

The knock seems now to have subsided...or maybe its just lost in the noise of the new boooost! Feels like a lot more than a 40bhp hike, would recommend a jolly green monster remap to anyone considering. Took me from 274 to 313bhp without much effort at all.


Now I just need to consider the virtues of my oh so quiet exhaust versus the much more purposeful types that Don and NDS have got on their beasts!
 

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Mad Englishman.
MY06 Forester STi 6MT
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4,157 Posts
I say that's not bad from a "standard" FSTi:woohoo:

Bet you have a replacement panel filter though at least :cool:


On the fuel issue Ben (Ben was running BP Ultimate), I don't know whether you noticed how Charlie and Simon picked up on that so let me elaborate.
Towards the end of your mapping session when they had the map more or less complete, they did 2 power runs back to back after a little rest to allow the engine to cool.
On the 2nd of the 2 runs your FSTi made significantly less power (~10bhp) which was when they asked about the fuel through the windscreen. What they were picking up on was that the engine was most likely retarding itself on the 2nd run due to an increase in air intake temps, through the heat generated from the first run. V-Power (or a better fuel than Ultimate) would normally have overcome this, so when they saw it happen they guessed you were running "shoddy" fuel. Normally Simon could maybe have done something about it by giving the turbo a bit more blow in the mid-range, but as he was maxing out his parameters (hence the pill mod) you saw the consequential dip in performance.

Still, a flippin good performance though...and welcome to the 300 club :bananapartyhat:






 

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2004 Forester Sti 6 MT
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723 Posts
I recall quite a few people mentioning that BP Ultimate is not as suitable as Vpower for Subaru's. I wonder why that is? When I picked up my car for the first time I had to go BP Ultimate as I was running out of fuel and there were no Shell garages around. I recall it 'felt' a bit rougher than when I put in Vpower, but could be imagination.
Anyhow, well done on the map and good news they never found anything serious in the 'clunk'.

Could you see any of the airshow from SRR? I got back from Holland around 16:30 and saw the red arrows as I drove down the M3 from Heathrow.

Al
 
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