Lotus Elan Central

by **JIMBO** » Wed 07.06.2006, 23:27

Advise please,
I now have a VERY high pitched whisle/screech (yes even worse than the mother-in-law) at aprox, 6000 rpm with about 0.5 bar of boost. At this point the boost drops back but the car continues to Accelerate. I've not noticed this before, and the only change to the car is a new Peco exhaust.
any idea's please.
PS
It's hard to tell if it's a whistle or a screech as my hearing is still recovering from the new exhaust
Jim

by **Dovey** » Thu 08.06.2006, 01:25

Here's an amateur guess: knock.
I'm sure someone will laugh at me in a minute and tell you right :-D

by **Candles** » Thu 08.06.2006, 07:43

Either a leak in the pressure side from the turbo or the bearings in the turbo on the way out. I doubt it is the latter as you'd be burning oil etc first so check all the hoses beyond the turbo for a split. It might be worth driving someone else's to compare.

Candles.

by **Doug** » Thu 08.06.2006, 08:57

Candles wrote:It might be worth driving someone else's to compare.

that's what I keep telling the wife, but she's not given in yet . . .

by **JIMBO** » Sun 18.06.2006, 22:37

Candles wrote:Either a leak in the pressure side from the turbo or the bearings in the turbo on the way out. I doubt it is the latter as you'd be burning oil etc first so check all the hoses beyond the turbo for a split. It might be worth driving someone else's to compare.

Candles.

Hi Candles,
Thanks for your advise. I have checked the hoses and cant find any pressure leaks. The inlet pipe from the airbox to the turbo was loose so I tightened that after cleaning an excess of oil from around and inside of it. The rod from the wastegate capsule was also very stiff so I freed that off. When I checked the oil it was low after only 500 miles. A test drive revealed that the problem is still there.Another sugestion is that the exhaust is causing the problem and I should port the wastegate.
I have searched the site and cant find any reference as to how to go about this. Can anyone point me in the right direction, or would I be better to take it to a turbo specialist ?
Thanks
Jim

by **Dovey** » Mon 19.06.2006, 10:34

Did you have your timing checked before fitting your exhaust? If you didn't then get it done! I won't guarantee it will fix it but it has a good chance and it will help your engine run better anyway. And it's cheap, unlike porting wategates...

Porting the wastegate is a turbo off job. I would say you need to know what you're doing

Try the base timing before you go to a turbo specialist though.

By the way, I'd guess you are using fully synthetic oil and it sounds a bit thin. Try a good semi (10 or 15/40) instead.

by **Monty** » Mon 19.06.2006, 13:22

Jim

It`ll be nothing to do with the exhaust, the only thing u may get is overboost but would not cause the screeching noise. You sure it`s not like a whistling noise which is normal or maybe flutter type noise when u come of the boost?
Try reving the car from under the engine bay to see if u can here it again.

Just hope it`s not the turbo :roll:

ps make sure u`r alt and PAS belts tentioned correctly.

by **RatHead** » Wed 21.06.2006, 23:34

Jimbo

I get this noise that you describe and I have recently fitted the Peco exhaust. Im pretty sure I didnt get it before.

Mine is different though in that the boost does not drop off.

I only get the noise under very hard acceleration.

As regards porting the wastegate - I called a turbo specialist recently (Well Lane Turbo Centre) and asked about doing this. He seemed a little surprised I was considering such extreme measures to solve what he thought on the face of it seems a very minor problem.

by **Dovey** » Thu 22.06.2006, 18:54

Still think it's a timing issue...

Look at ESM's website. To summarise: if you want more boost your engine must be running well and your timing correct...

by **JIMBO** » Thu 22.06.2006, 21:56

Thanks for all your help and advise guy's. This doesn't sound
like a job that can be fixed with a hammer (the only tool I can
use effectively) and so I have booked it into G.S.T. Performance
in Newmarket on the 30th. I will let you know of any findings and
of any fixes. As I am using the car daily ( my BMW suffered a Dukes of Hazzard landing) I use the whistle as an indication to change up or back off. Pitty I didn't back off in the other car !

Jim

by **RatHead** » Thu 22.06.2006, 22:17

It will be interesting to hear what they say Jimbo - keep us posted.

by **GeoffSmith** » Wed 28.06.2006, 19:32

Hmmmmm. Can I join the screaching mother-in-law club as well. I think it must be exhaust related because:
a) I didn't get it with the Supershit chip and MBC - when I first got it and took it to the red line several times :twisted:

b) I didn't get it with the Supershit chip and MBC when the wastegate stuck - left half my tread at some traffic lights and hit the red line before I knew it in 1st and second
c) I didn't get it with the stock chip and MBC
d) I didn't get it without stock chip without the MBC
e) I get it with the Peco

Don't laugh, I've only just opened it up since getting the exhaust as I'd got used to being light on the throttle to avoid fuel cutoff and I've only been tootling down the lanes to work. Time to paint it BRG? :-D

My whistle happens under heavy load at about 5000 rpm upwards. I initially thought air leak as it was soon after removed the MBC, but having read this I'm not so sure.

What about the wastegate oscillating as it struggles to control the overboost creep?

Look forward to hearing back from you on Friday Jim.

Geoff

by **JIMBO** » Wed 28.06.2006, 21:12

geoffsmith wrote:Hmmmmm. Can I join the screaching mother-in-law club as well. I think it must be exhaust related because:
a) I didn't get it with the Supershit chip and MBC - when I first got it and took it to the red line several times
b) I didn't get it with the Supershit chip and MBC when the wastegate stuck - left half my tread at some traffic lights and hit the red line before I knew it in 1st and second
c) I didn't get it with the stock chip and MBC
d) I didn't get it without stock chip without the MBC
e) I get it with the Peco

Don't laugh, I've only just opened it up since getting the exhaust as I'd got used to being light on the throttle to avoid fuel cutoff and I've only been tootling down the lanes to work. Time to paint it BRG?

My whistle happens under heavy load at about 5000 rpm upwards. I initially thought air leak as it was soon after removed the MBC, but having read this I'm not so sure.

What about the wastegate oscillating as it struggles to control the overboost creep?

Look forward to hearing back from you on Friday Jim.

Geoff

And there I was , thinkinking I was all alone in the world with the mother in law from hell. Sorry to hear you have the same problem, I'll let you know the outcome when mine has been looked at.
Regards
Jim

by **GeoffSmith** » Wed 28.06.2006, 21:42

Good luck Jim. I'm sure it's nothing too serious, given the number of occurences.

Geoff

by **RatHead** » Wed 28.06.2006, 22:50

I dont know how I would best describe the sound mine makes. The nearest thing i can think of is the sound you get when you hold a wine glass by the stem and run your finger around the top of the glass.

It is only at high revs and high boost - and I have done a fair few miles in the car since I had the Peco fitted and its not using oil.

I will phone Chris Foulds tomorrow and see what he thinks it could be.

by **GeoffSmith** » Wed 28.06.2006, 22:58

That describes it pretty well Peter, similarly at high revs and boost.

by **Monty** » Wed 28.06.2006, 23:05

Before the Peco, i use to have a open air filter and i could hear the turbo wizzing but it wasn`t a screeching noise and when coming off the boost i got and still get the fluttering noise cause i`ve removed the dump valve which is just the turbo stalling.

by **GeoffSmith** » Thu 29.06.2006, 00:40

I still get the fluttering noise when lifting off. Mine is a lot higher frequency than that and increases in pitch and amplitude from ~5000rpm to 7000rpm.

Why did you remove the dump valve Monty? I thought they saved the turbo and gave better pickup changing gear.

by **Dovey** » Thu 29.06.2006, 00:59

Why did you remove the dump valve Monty? I thought they saved the turbo and gave better pickup changing gear.

Thats the sound of a can of worms being opened :-D

Lotus Elan Central

HIGH PITCHED SCREECH AT 0.5 BAR BOOST

HIGH PITCHED SCREECH AT 0.5 BAR BOOST

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