Escaping boost??

[clarky5150]

Morning all. Was wanting to run this by the more experienced in Elan turboness
I currently have an issue with hessitation in power when on boost having just recommissioned the car since purchase. I have scanned through the various posts regarding base idle, CAS, MAP, coils etc but everything on the car, tickover, off boost performance etc is fine.
I have however noticed the following which im sure my last elan (which was four years old so quite some time ago) didnt do.
On boost i hear a fairly loud whooshing noise under and to the rear of the car almost like a continuous dump valve being activated. The car has an aftermarket stainless exhaust which is slightly bigger bore i believe than standard. I have wiggled the gate and my boost guage shows constant pressure when on boost.
Could this be a leak on the intercooler piping causing the stammering or is the noise normal?

Any help would be appreciated afor i start tampering with timings etc in this cold and rainy weather.
Ta.

[Alan_C]

The boost gauge is very unreliable, so don't pay it too much attention, but what is it indicating when on boost? A more reliable way of knowing what your car is doing is to provide an Elanscan of a logged run, read through the Elanscan topics for more info. There shouldn't be any real whooshy noise when on boost, you'll hear the turbo spool up though, and get a reading on the boost gauge, but from what you describe it does sound like escaping pressure? Could be a split high pressure pipe, loose hose clip, puntured intercooler? The boost gauge should read about 0.6 BAR on max boost, if you're loosing pressure I'd expect it to read lower?

As for hesitation when on boost, most probably ignition related, check the condition of plugs, leads and coils. Could you describe the hesitation in more detail, does the car misfire, pop and bang etc when on boost?

[clarky5150]

No pops bangs or farts just a feeling of holding back on full throttle. The boost guage reads .6 bar and is giving a steady reading. The noise is definately not spool up but does sound very much like escaping boost.

[GeoffSmith]

I had the clip break on the pipe to the plenum and it hissed on high boost (before it gave way completely and it hissed all the time). Remove the turbo inlet pipe at the filter and blow... there should be no leaks but if there are you should be able to find out where they are.

















































Then go an look in the mirror!

PipeBlow.gif

[scottswatches]

this sounds exactly like the problem i have been experiencing. I've changed plugs, leads coils and CAS assembly with no difference. I'll check the turbo pipes today/tomorrow and if i find anything i will post the images

[chetepongo22]

I have been feeling the same.Like scaping boost only in full throttle.I also changed a stainless steel exhaust a little bigger but only the last section of it, I did not think this could influence the turbo. This week I will visit my mechanic and we will try to fix it or find why it is...

[Alan_C]

I found my high presure leaks by removing the turbo inlet pipe and fitting a rubber bung into the turbo with a hole bored in it. Plugged an air line in it and blowed in air (engine not running of course). Not so much that the pipes blow off, but enough to see if there are any leaks, you'll hear where they are if you have any.

[tigerdog]

I found my high presure leaks by removing the turbo inlet pipe and fitting a rubber bung into the turbo with a hole bored in it. Plugged an air line in it and blowed in air (engine not running of course).

Hats off to you - this is one of those incredibly elegant solutions that causes one to ask "Why didn't I think of that?"

[GeoffSmith]

I found my high presure leaks by removing the turbo inlet pipe and fitting a rubber bung into the turbo with a hole bored in it. Plugged an air line in it and blowed in air (engine not running of course).

Hats off to you - this is one of those incredibly elegant solutions that causes one to ask "Why didn't I think of that?"

... and for those without compressors!