Dual Throttle Bodies

[mobymidge]

I am having problems getting my DTB's set up correctly. I have followed the instructions written up by Godless Commie on the Dual Throttle Body thread but I continue to get lots of noise especially under load. I have tried opening up the SC throttle and also closing it down but I continue to get lots of noise. The belt is nice and tight so I don't think it is sqeal from that.

The noise also comes with a high pitch whistle. The combination of noise is enough for people to look around before I pass them.

My set up is as follows;
91 NA 1.6
M45 SC with TR Fabrications fitting kit
Mini bypass valve (vacuum taken from inlet manifold)
Vacuum manifold (central point for all vacuum feeds)
MS1 V3 standalone ECU
BMW vTPS
Bosch 2 wire IAC
TPS and IAC fitted to post SC TB

Any help or advice would be greatly appreciated.

[GBS]

your pre-sc TB is probably more than "cracked" open. Remove any slack in both TB cables.