Pour info les échanges que j'ai eu avec le fabricant : conclusion c'est normal tu n'as qu'a serrer le V-clamp comme un bourrin ...
"Hello Christian
I have received your e mail regarding your vx220 turbo down pipe fitment from Elise Parts.
I’m sorry to hear your finding it difficult to fit the system.
I have looked at your photos and see that there is distortion on the ring face. We have inspected a complete down pipe we have here and there is also a 0.325mm distortion across the ring face we have never had a problem with this previously as the gasket between the ring face and turbo face took up any deviation in flatness.
As for your second point please do return the 180degree bend to us at the address below so as we can check it in our jigs to make sure the item is correct.
Regards,
Chris Tullett
Hi,
For your information for Z20LET engine application, there is no gasket between the exhaust flange and the turbo flange.
The "airtightness" is done by direct contact of the steel surfaces, this is the reason why the flatness of the flange must be perfect.
The OEM and my former exhaust system were installed without any additional gasket, and I never had any exhaust gas leakage.
You can check this information from Vauxhall
Please advice
Best regards
CCD
Afternoon Christian
In response to your email regarding the “airtightness” I have spoken to a specialist Vauxhall tuner here in the UK that we supply turbo system’s to. They say this is a common problem and they find that they need to do the clamp up very tight to achieve a good seal. They recommend if it still will not seal to replace the clamp.
As for the alignment of the flange they recommend that you get the whole exhaust mounted and all the bolts in place before anything is tightened, this allows the exhaust to settle to its natural position before finally doing all the bolts up.
I hope this helps.
Regards,
Chris Tullett
Dear Sir,
In my opinion all these explanations are not very "mechanical" nor professional for a "specialist" ...
I will try to perform a lapping on your exhaust flange in order to restore its flatness and assume a correct gas tightness with the right torque (8 N.m) applied to the clamp system. (How can you explain there is no leakage on the OEM system when you tighten the clamp system at only 8 N.m)
For the U bent, I will cut and adjust it myself in order to avoid too much stress in the whole exhaust system and save time for the reassembling of my car.
As a conclusion, I am disapointed, because your exhaust system have a good reputation on the forums and for the price I am waiting for a perfect "plug and play".
Best regards
CCD"