Overboost after wastegate porting!

[vi11ain]

After porting the wastegate I put the turbo back into my car on Sunday, took it for a test drive......and experienced overboost, with error code 31!

On the upside, the overboost took a lot more provocation than it used to, so the porting has improved matters a lot and I know that the turbo is working well!

Just, so you know, my setup is as follows:

Peco 2 1/4" exhaust
Piper Precat Eliminator (PCE)
Standard turbo (just reconditioned), wastegate ported using Bosch conical grindstone.
K&N air filter (in standard dustbin housing)
Baily motorsport recirculating dump valve.

I guess that the PCE (which I fitted at the same time as the ported turbo) might have reduced the backpressure further, thus making the overboost conditions worse (originally started when the exhaust was fitted), but I have my doubts about that.

I'm thinking (and hoping!) that the problem will be with a leaking wastegate actuator hose - I guess the only real way to test that is by replacing it and blocking it off from the BCV, so that the mechanical boost limit of 0.41 Bar should be all that it can attain. I'm going to do a run with ElanScan tonight to see what that turns up.

So, has anyone else had to port their wastegate further than the normal 20mm to get boost back under control following an exhaust system change?

Ben

[ailwyn]

I've not heard of anyone porting beyond 20mm.

The wastegate actuator rod does move smoothly and for full travel (about 1") does it? (I only ask as you've not mentioned it)

Check for a blockage or split in the air hose that's going to the actuator.

Running ES should give some clues, at least as to what the ECU is trying to do.

Ailwyn

[Specky]

A code 31 is normally indicates a sticky waste gate...

do the waste wiggle...

saying that I keep getting the same code unported...I Keep spraying WD40 and doing the wiggle, The WD40 quickly burns off,

When I Port the wastgate next week the wastegate will be cleaned up totally



TTFN

[Specky]

one other thing that really helped when doing the waste gate wiggle was some advice from Bristols own fairy... it was to disconect the vacum capsule, this allows the bracket to move forward, closer to the clam and gives you more of an un obstructed wiggle range.

TTFN

[GeoffSmith]

[Specky]

:evil:

I could of said Bristols own Pinky, but that would just confuse matters...

Cheers again Geoff...

TTFN

[vi11ain]

A code 31 is normally indicates a sticky waste gate...

do the waste wiggle...

saying that I keep getting the same code unported...I Keep spraying WD40 and doing the wiggle, The WD40 quickly burns off,

When I Port the wastgate next week the wastegate will be cleaned up totally



TTFN

The wastegate's as loose as a loose thing - the turbo's just been reconditioned and there's definitely no stickiness there - in fact there wasn't any problem with that before it was reconditioned....

I'm going to test the movement of the actuator by applying some pressure to the hose, although the capsule did check out ok when Turbo Developments put their hand pump on it.

I'm keeping my fingers crossed that it's the old pipes.....

Ben

[dapinky]

:evil:

I could of said Bristols own Pinky, but that would just confuse matters...

Cheers again Geoff...

TTFN

Nowt to do wiv me.......



....I aint from Brizzle.

[Specky]

A code 31 is normally indicates a sticky waste gate...

do the waste wiggle...

saying that I keep getting the same code unported...I Keep spraying WD40 and doing the wiggle, The WD40 quickly burns off,

When I Port the wastgate next week the wastegate will be cleaned up totally



TTFN

The wastegate's as loose as a loose thing - the turbo's just been reconditioned and there's definitely no stickiness there - in fact there wasn't any problem with that before it was reconditioned....

I'm going to test the movement of the actuator by applying some pressure to the hose, although the capsule did check out ok when Turbo Developments put their hand pump on it.

I'm keeping my fingers crossed that it's the old pipes.....

Ben

If they've had a play... is the rod set to the correct length?

TTFN

[vi11ain]

The wastegate actuator rod is of the fixed length type, but I did measure it while it was on my living room table - from the face of the bracket to the center of the pin it comes to 98.5mm, which I believe is about right.

I didn't manage to get a helper for Elanscan logging last night, but hopefully tonight I'll get it done.

I'm thinking of disconnecting the wastegate actuator for a test run, so the wastegate remains open fully due to the action of the exhaust gases behind it. Any trace of overboost then would indicate that the port needs to be bigger. I can't think of any problem with doing this as a test - unless someone here can think of something bad that might happen?

Ben

[Andy_J]

Have they put the actuator rod/waste gate actuator back in the right place on the turbo. seem to remember that you could lossen all the bolts on the intake side and rotate everything round

[GeoffSmith]

Interesting observations Andy (and sparked a thought on Max and Andy's problem ) - the capsule position can be changed if all the clamping bolts are released, so it's important for it to go back in the same position. Rotated, it might be difficult to fit with the wastegate being forced fully closed but might better explain an open wastegate.

[paulwatkins]

That is a possible cause, especially if its recently been split for refurbing.


But I dont think this is the case for the - Your thoughts after installing the Everest chip - saga! IIRC someone has been fiddling with the plumbing recently. My monies on that over there.

[bobbrown]

I know this may be a silly question but has anyone actually checked the settings for the waste gate as per the manual?

wastegate1.jpg

wategate2.jpg

I know that the tools may not be available to most people but I am sure something could be made up.
The finger should be easy enough and hand tools should be enough to make one, dial gauge cost about a tenner and you could use a foot pump to get the pressure.

I do not have this problem and it is not going to as my Elan does not have a Turbo.

Bob

[esprit888]

Would that actually work ? I would have thought that due to the design the exhaust gases exiting the turbo would far exceed the backpressure in the system and keep the waste gate closed not open? As for the 'Your thoughts after installing the Everest chip' saga i thought all he did was install the everest ? someone playing with hoses was only during troubleshooting ? Thats a different kettle all together!

I'm thinking of disconnecting the wastegate actuator for a test run, so the wastegate remains open fully due to the action of the exhaust gases behind it. Any trace of overboost then would indicate that the port needs to be bigger. I can't think of any problem with doing this as a test - unless someone here can think of something bad that might happen?

Ben

[vi11ain]

Would that actually work ? I would have thought that due to the design the exhaust gases exiting the turbo would far exceed the backpressure in the system and keep the waste gate closed not open? As for the 'Your thoughts after installing the Everest chip' saga i thought all he did was install the everest ? someone playing with hoses was only during troubleshooting ? Thats a different kettle all together!

I'm thinking of disconnecting the wastegate actuator for a test run, so the wastegate remains open fully due to the action of the exhaust gases behind it. Any trace of overboost then would indicate that the port needs to be bigger. I can't think of any problem with doing this as a test - unless someone here can think of something bad that might happen?

Ben

The exhaust gases come towards us out of the turbo in the picture below, so they would definitely tend to push the wastegate open.

As for the positioning of the compressor housing (on which the wastegate actuator is mounted), that's a very good point, although I noticed that the housing had been marked with a centre punch next to a convenient casting mark, so that would indicate that they've been careful to get the positioning the same. Also, the actuator seemed to be in the correct position when I reconnected it and the housing "looks right". However, I do have detailed "before" and "after" photos, so I'll do some careful comparisons to be sure.

I've got some new tubing now, so I'll replace that as a matter of course. When I get time I'd like to do the test as per the service manual as suggested by Bob - that should settle any questions over the actuator, but disconnecting it altogether (and maybe fastening it open) should sort out questions over the port size.

Ben

tn_After porting 2.jpg

[esprit888]

Oops, my bad, have not had the first coffee of the day yet! plus i REALLY do need glasses now! Wiring it open would remove any doubt but your picture has me wondering about the other saga, has anyone ever had the disc fall off the wastegate arm ? (appears to be a riveted type attachment in the pic not a weld?)

The exhaust gases come towards us out of the turbo in the picture below, so they would definitely tend to push the wastegate open.

As for the positioning of the compressor housing (on which the wastegate actuator is mounted), that's a very good point, although I noticed that the housing had been marked with a centre punch next to a convenient casting mark, so that would indicate that they've been careful to get the positioning the same. Also, the actuator seemed to be in the correct position when I reconnected it and the housing "looks right". However, I do have detailed "before" and "after" photos, so I'll do some careful comparisons to be sure.

I've got some new tubing now, so I'll replace that as a matter of course. When I get time I'd like to do the test as per the service manual as suggested by Bob - that should settle any questions over the actuator, but disconnecting it altogether (and maybe fastening it open) should sort out questions over the port size.

Ben

tn_After porting 2.jpg

[/quote]

[max and andy]

Great photo.

[paulwatkins]

As for the 'Your thoughts after installing the Everest chip' saga i thought all he did was install the everest ? someone playing with hoses was only during troubleshooting ? Thats a different kettle all together!

Maybe my mistake but I was sure there was an MBC involved over there prior to the chip install....... that was in, then out, in? then out again?, hoses disconnected, plugged back in, hoses replaced....or did i imagine that?

The car has to be set back-up to stock, then start from there. I dont think that has been acheived yet.

Sorry for the I should of posted over there

[max and andy]

I removed the MBC before fitting the Everest. I replaced it again for a short run to see if i could find some boost and to check if the Electronic boost control was at fault. I changed the hose as a precaution as it was one of two hoses i had been touching. Andy Sorry