After some help last week from the kind memebers of Scoobynet, I've finally made my own detcans to see whether the activity I'm seeing on my knocklink is anything to worry about or not.

I'm not ashamed of sounding stupid here when I ask "what does det sound like?"

In other words what noise am I actually listening for? I know I'm listening for something unusual, but what?

Can anyone describe it?

LOADS of people "talk" about det on here but I bet only a small percentage actually KNOW what it sounds like from first hand experience,through det cans rather than from being TOLD what it sounds like.

I'm looking for the best description that any of the experts out there can come up with.

Thanks in advance.

 

Best bet is to listen to it on someone elses car.

This is quite useful.

As is this

Andrew...AKA the man of the 2MB favorites folder...

 

Nice one Andrew, thanks.

Unfortunately the sound card on my PC is broke and I'm waitng for a new one. LOL. Typical.

I'll have to look at theses Links on my mate's PC.

Cheers

Rich

 

Rich,

sorry to hear that you have a problem.

Det will sound like a 'tinkling' noise - almost like broken glass being dropped onto a metal plate.

I think it will be pretty clear when you hear it - any odd sounds above the noise floor of the engine running could be det. The worse it gets the louder it will be.

Best to run around for a while off-boost so you can get to hear what the engine and valve train sound like. Say up to 4000rpm without booting it. Then try again on boost.

Rannoch

 

Cheers Rannoch,

I'm not certain I'm actually suffering from det. I think the activity I'm seeing is something else, background noise etc etc, so I just wanted to make sure.

Rich

Edited to add the strange thing is that I have run all summer with little or no knock activity anmd now the cold weather has come, the activity has increased. Seems a bit paradoxical.

[Edited by RICH WILD - 10/28/2003 9:22:22 AM]

 

Things could have leaned out now that the air is cooler/denser/moister?

Andrew...

 

Drawing pin dropped in an empty tin can.

If it's bad the tinkling will almost sound like a crackling. As you retard the ignition, or lower boost the det will deduce, as it fades it will become quieter and more intermittant, like "tink......tink............tink..tink..tink....... tink" almost random. Changing things safer still, and you may just hear one or 2 plinks as you go through the revs.

You are not listening for completely regular events that go up and down with revs under zero load. You should be able to hear the injectors ticking quietly (sounds like relays switchings), and possibly the cam followers tapping (slow in comparison to engine revs.

You need to get some heat into the engine bay and really work the engine for a time to get accurate results, or you may get det in 5th gear climbs that you weren't expecting.

 

Cheers for that Pavlo,

Andrew, no I doubt it. EGT's are fine (about 625 max in downpipe) and Lambdalink is on highest green on boost. I've also recently upped the fuel pressure to 3 bar at idle from being at standard, so the car should be running richer if anything

Rich

 

Found out what the "odd" knocklink activity was last night.

It was the first signs of my gearbox expiring.

Last night KABOOM! bye bye 3rd gear.

Knocklink did an impression of Blackpool when it happened.

Oh well, back to the breakers yard.....again.

 

Rich,

No way!!!!

Which one was this, your 96 or 97?

In consilation at least your getting no det though



Iain

 

Rich,

As a matter of interest where in the rev range did you get the extra knocklink activity, what did it look/sound like?

Are you going for an STi box?

Andrew...

 

Hi Iain,

It's the 97. The 96 has no engine in it. I have 2 Subarus and now I can't drive either of them!

LOL, yeah at least I have no det though

Andrew,

That's why I didn't think it was det, hence the reason for me checking wit the det cans. It was totally random. Sometimes it would do it, other times it wouldn't, mainly high rpm (above 6000), sometimes lower, but always on full load.

Was slapping it about last night up to 1.6bar to try to force it to det so we could hear it

next thing POW! my mate said "oh ****, I heard it then" I said, "no you didn't, that's my box, I can't get a gear!".

I'm getting another UK box for now, a later one though, I like the ratios for motorway cruising and top end. STi just too short with the 4.44 and my measly 7000rpm redline.

Going for a STi box on my white chunk when it finally gets it's engine back in, as that won't be a daily driver, so I'm not arsed about it doing 10000rpm@70mph.


Cheers

Rich

 

You used to be able to hear det/pinking quite clearly on old A series mini engines. You put the car in a high gear and booted it at low revs - you couldn't mistake the noise for anything else. I'm not sure if this is the same noise as det on turbo engines though?

F