Turbo normal sound

[Manute]

Hello!

I've been a member of this community since 2003, it's been a while! However I lacked time to connect and I've been absent a few years.

My background is,I have an 86' 951 i bought in a less than perfect state...was not expensive but the poor car was beaten up, eating almost 1 liter oil per 160 miles or so. Imagine...
5 year ago I overhauled it, was a timely and very expensive overhaul, a few times the price of the car, itincluded new piatons with rings, new transaxle, new turbo (k26/6 since I wanted original specs) head work...etc etc. Quite expensive but I got an almost perfect mechanical state, no oil consumption at all and great performance. I also added a lindsey boost enhancer that really did it's job.

More recently I did some maintenace changing part of the steering, new shocks, new clutch pump, etc. This was the last maintenance, 2 months ago. Not cheap also....

So with this background, here is my question related to the topic...

Yesterday was driving through a tunnel, when I noticed the sound ofthe turbo spooling up and down while accelerating. And I thought "how cool the turbo spooling"... But after exiting the tunnel I turned off the stereo and while accelerating, I still heard the turbo spooling up and down...very subtle, a very light " pssttttt.....psssssst". Then i tought "did I heard this before?? Is this normal?" I kept driving and I still heard the very subtle sound of the turbo spooling up and down. When above 3k rpm, I heard nothing, and at the end of the trip when the car was hot, the sound was even more sobtle, almost non noticeable.

So now I dont know if i'm too paranoid about this...I remember when the car was not repaired and i had the original busted turbo that it was quite noisy, but i cant remember hearing it after the overhaul.

So...are you supposed to hear a little bit of turbo spooling on a stock car? Or should you hear nothing? I checked hoses and apparently they are ok, and oil consumption semms normal, almost zero.

I'd like to know if i'm too paranoid or not...what is your opinion??

Thanks!!

[mytrplseven]

I've been restoring an '86 951 for three years now and haven't really run the engine much. But, when I did, I didn't hear a turbo spooling sound. I need to say at this point, one of the first things I did was send the turbo to a local specialist who rebuilt it, including bearings, balancing and seals. It made NO discernable noise.

[Manute]

Thanks 777! Thats why I am worried...I don´t remeber any turbo sound with the new turbo. And I´m not considering it to be faulty with only 13.000 km since new...I´m frightening!

BTW, I love your 951 decoration, Martini racing was one of my favorites.

Thanks for the info!


(P.S. do you fly B-777?)

[Peter Graham]

I can hear the turbo spooling/unspooling on our new-to-us 130K+ '86 951 but there again I am attuned to listening to all the noises older cars make. Realize that is very hard to accurately describe a noise in words to the point where others can diagnose and issue, if any.

Peter

[Manute]

Originally Posted by Peter Graham

I can hear the turbo spooling/unspooling on our new-to-us 130K+ '86 951 but there again I am attuned to listening to all the noises older cars make. Realize that is very hard to accurately describe a noise in words to the point where others can diagnose and issue, if any.

Peter

Thanks Peter, I feel more relaxed if other users with good working 951´s can hear it too

[Charlesberry]

I can hear mine spooling up.

[DannoXYZ]

You may have leaking intake hoses. If it gets worse, you may get some stumbling when opening up throttle.

[Manute]

I checked yesterday main hoses and connections seemed fit. I took a ride and the sound it's more like a howl...like there is a little ghost inside
It's barely noticeable with stereo on, so I think it was always there. I have an aftermarket pressure/vaccum gauge and pressure rises up to 13/14 psi, and when coastin gets down to -20 inhg, so I hope there are no leaks...

Maybe I got a bit paranoid...

[DannoXYZ]

Remove compressor-bypass valve and test blowing into inlet and outlet