I have just completed my S/C installation on my MX5. This uses ( minimum length ) silicone elbows to join hard pipes for the intercooler. The TB is pre charger so that under closed throttle conditions the system is under vacuum. Despite the minimum exposed length the hoses collapse when warm. The collapse is not complete, the resulting cross section is sort of figure 8. This does not seem to affect driving but my rolling road man says the airflow is compromised to the extent he cannot calibrate properly. Hoses are seemingly good quality multi layer from Viking performance . Is there a form of stand alone ( internal ) spiral wire reinforcement available? Any other ideas welcome. TIA.

Really isn't a great place to use silicone hose. You should be using aluminium hose and silicone connectors. Alu hose is incredibly cheap.

https://www.ebay.co.uk/itm/Universal-2-25Inch-57mm-Alloy-Aluminium-Pipe-Straight-100mm-Brushed-Swaged-Join/183684602555?hash=item2ac4749abb:g:EaoAAOSw Xq5cZHr~


[Edited on 4/3/19 by coyoteboy]

Twin throttle would solve it?

Could you not slide ali tube inside the hoses to reduce the unsupported distance between pipes?

Use ally bends with straight silicone joiners? You could get the ally tubing to butt join eBay Item

Thanks for the inputs. Problem is I cannot get tight enough ali bend to suit due to height of intercooler. This is already on the ground clearance line so I cannot lower it. I am considering a clamshell type tight exhaust bend as an option. Will not look good but should work.

get the intercooler adjusted so the in and out dont need bends?

Well in searching exhaust bends I think I have found the answer. For the benefit of anyone else finding themselves in this position I have found that stainless steel mandrel bends are available with bend radius equal to pipe diameter ( have not found any ali ones that tight ) so that should work for me. Should look ok too. Ebay here I come!

Wind your own coil spring from stiff wire and insert into the silicon pipes?
QED.
Cheers, Pewe10