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      02-13-2021, 05:07 AM   #5
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KennyP's Avatar

Drives: 2009 Havana E89 Z4 Sdrive35i
Join Date: Apr 2016
Location: Estonia

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7.5 inch is definitely considered to give better air temps, but it requiers some cutting to fit. I was thinking CSF 5" or thicker 5" Wagner intercoolers are a good way to go. COBB itself sells CSF 5" intercoolers and allows running stage 2+ with it. So it is probably enough. There are cheap 5 inch intercoolers on the market aswell but they are all thinner, so already based on that not as good. Build quality, core design etc are other factors where cheap ones probably suffer.

With intercoolers there is a debate on intercooler connections though.. Some say oem connectors become a bottleneck and connections with silicon tube like on VRSF are better. With outlets i assume you have to use silicone tube connections anyway?

Problems with TIAL blowoff or any other big single blowoff come from the vacuum line you run to it from the intake manifold. I have read that oem vacuum line is too small and its recommended to plug oem vacuum line connection on the intake manifold and use a bolton adaptor with bigger connector and run a bigger vacuum line from it to blowoff valve to have it actuate better. If you want to use oem vacuum lines then dual dv valves or blowoffs work better with them. Im not sure on OEM dv-s being that good. they are plastic afterall. I have read that they can leak and so on.

On that adaptor:
2009 35i DCT Havana brown with ivory white interior. Mods: Cobb stage 1, BMS DCI, KW V3 suspension, M3 front control arms, Michelin Pilot Super Sport tires.

Last edited by KennyP; 02-13-2021 at 05:15 AM..
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