john banks

Switching headers about and ended up with a medium pitched squealing noise over 10 PSI but drives fine. The noise only happened after about 20 miles driving but now everytime, if anything not the first time after going on boost for a few seconds once warmed up but every time thereafter. Pitch does not change with revs or boost, but its volume is boost related. Not the turbo, intercooler, intercooler hosing, dump valve as swapped them all to see. All the joints from manifold to downpipe are tight and double/triple checked. However, switched the headers without new gaskets because I was on the hop and has been OK before. Hoping this half ar$ed thing is the reason as it would be very simple, but odd that tightening made no difference. Gaskets really should be one use but I was unprepared.

Wondering if I have ported the OEM headers a bit far, but only took out to the soot lines. Will need to have another look. Can't see/feel/hear any blowing. I did put the uppipe in a vice to smooth off a few rough bits, but only tight enough to hold it, hopefully not to crack it. There is an expansion bit in the headers too which I will need to look at.

Thought about going to the rolling road to put it under load to try and hear where it was coming from as it is a bit baffling.

Any suggestions from nuts and bolts gurus or anyone appreciated. Anyone had similar before? Asked a few folk and they all seem baffled. We thought it was the turbo originally, but thankfully not

Oh the woes to getting a fast(ish) car

Don't think it is the inlet pipe since we did not disturb it and I can see no leaks.

[Edited by john banks - 9/8/2002 9:07:15 PM]

UkLegacyT

John, i had the same problem when i put my original system back on for its mot.
it was the turbo to downpipe gasket fluctuating. looked fine, everything tight, but when i changed the gasket it was fine. thought it was my turbo at first.
it was really loud squeal.

ian

doing quite a few bits to that motor now eh

john banks

Just been out with the laptop and sound recorder, but the recording is useless. I'll change all the gaskets and see then. Hope it is that simple.

ustolemyname??stevieturbo

iTrader: (1)

Plug up ( get someone to cover it , and not with their hand ) the tailpipe, then any leaks should become apparent at tickover, unless it really takes some pressure to make them leak.

UkLegacyT

hopefully, good luck

re the headers. i ported mine to the soot lines. think they ended up going from 38mm (original) to 45mm. no probs with mine.

john banks

Stevie, the presumed leak is one of those nightmare ones that you can't reproduce in this way - it needs substantial engine load. Silent as a mouse when revved with the tailpipe covered.

The amount you ported Ian makes me feel happier...

Stevie, just seen what you wrote about not using the hand - might be better if it is bunged up properly with a rag then.

[Edited by john banks - 9/8/2002 10:03:53 PM]

Pavlo

Hmm, bleeding s'net is slow.

Oh the quest for power. Headers on, headers off. Headers are fabulous, headers are hmmm, not sure.

John man, you're a bleedin nightmare!

I'll give you £50 for your headers so you can buy some gaskets!

Gaskets probably the problem, I don't think they like being torqued up with different headers etc. Although 1 set of gaskets used for each type might work.

paul

john banks

Headers were very nice with the TD04L hyrbid because boost was never far away and the top end was the impressive upside. With the VF hybrid it is a bit too lacking low down. So they were matched to my driving style with the TD04L but not with the present turbo.

ustolemyname??stevieturbo

iTrader: (1)

I just meant so that you didnt get burnt. I ported mine too, and have no probs, altho was careful not to take toomuch off. Didint measure, but I took mine to pretty much the lines on the gasket/soot all round. UK maniolds are slightly different to UK ones, but any damage should be visible. I have re-used old gaskets loads of times, but thats not to say, there couldnt be a gasket problem somewhere.

ustolemyname??stevieturbo

iTrader: (1)

So what manifolds are leaking, and why have you changed them??

john banks

The original ones. Changed because the aftermarket ones were a bit laggy with a bigger turbo. Objective achieved except the leak.

ustolemyname??stevieturbo

iTrader: (1)

You changed from std manifolds from tubular? or from tubular to std? or from tubular to ported std??? Im lost!!
Either way, which worked best for you?

Andy.F

Headers - Standard to ported standard to tubular back to ported standard.
Turbo - Standard to hybrid TD to hybrid VF

With most permutations in between

ustolemyname??stevieturbo

iTrader: (1)

Cant you make up your mind?????

Pavlo

I suspect the tubular headers have left their impression on the gasket, making it unsuitable for the cast headers. New gaskets ought to do the trick if they are leaking.

paul

David_Wallis

Id love to see someone bung my hks hiper with their hand

David

Pete Croney

John

Its definitely a gasket. The sound is created in the same way as you can make a noise by holding a blade of grass between your outstretched thumbs and then blowing on it. The raspy sound is the gasket vibrating in the escaping airflow.

It could be anyone of them, including the turbo outlet gasket.