Full Bore start – Strange banging noise?

[tsteenholdt]

Would any mechanically orientated PistonHeads readers be able to explain the strange banging noise I get when giving my Impreza Turbo a “full bore” start? (6-7,000rpm and drop the clutch).

Sounds like somebody hitting a sheet of corrugated iron with a metal hammer. Engine/gearbox banging against mountings? Some sort of clutch judder? Anybody got any ideas? Seems to have no detrimental effect but is rather loud.

PS. Yes, I know this type of activity will not do the car a great deal of good, but sometimes just can’t resist giving annoying Golf TDi drivers and the Max Power brigade a thorough pasting at the traffic lights

[trefor]

Which garage do you use?, I'll buy shares in them now ...

[manek]

OUCH!

I don't know much about Imprezas but, like all cars they will respond to such unsympathetically rough treatment by reverting to kit form. So I'd suspect it could be axle tramp, buckled/busted wheel bearings, UJs, driveshaft, gearbox -- in fact, anything in the transmission train between flywheel and tyre contact patch.

>> Edited by manek on Thursday 30th May 18:04

[ninja_eli]

Get the car looked at before you do any further damage to it. Could stop yourself from saving a load of cash if you don't.

[yertis]

yep I'd agree with all of the above. 4WD doesn't like this kind of abuse at all, because (obviously) the drive train can't shed the excess power in wheelspin like 2 wheel drive cars can. Also I think the Scooby gearbox is a bit weak - or so I've been told.

[.mark]

Sounds like your trying to get 4WD Spin? I would imagine - and I have been known to do this only once that the fastest getaway is be gentle with the revs/powertrain and get the car rolling, when it is plant the loud pedal and blow them all away?
I'm sure Messers Humphries & Heath could give you a more technical descrpton.

[adrianr]

Best case you have a loose exhaust mounting somewhere.

AdrianR

[moleamol]

Whatever you do, get it checked out. I've got a 300odd bhp Integrale that is fully sorted. I have made mistakes in the past by not paying enough attention and ending up with a £2000 bill. It could be anything, the clutch, one of the diffs, engine mountings, but whatever it is you don't want it to let go.

Just do yourself a favour and get a pro to have a look at it for you. They are not gonna charge for that and the repair could save you a tonne. And do you really need to drop the clutch at 6k for TDI's and MAX power 1.2 boys, slow take off then stand on it, works for me. Then you can save the clutch for the 6k starts against the cheeky TVR/Porsche type fraternity :P

[Paceracing]

I've heard of this before. It only occurs apparently on cars which run Shell petrol.
A quick fix is to gently ease the car into reverse at around 70 MPH and then quickly dump the clutch with around 6,500 RPM. Apparently you never get that clonking noise coming from the engine again!

Jas.

[McNab]

Thomas, you've knackered it, so sell it - tomorrow or sooner