do88 Performance Intercooler – BMW 135i / 1M / 335i (E8x / E9x, N54 / N55)

OVERVIEW

The factory front-mount intercooler on the N54 and N55 135i, 1M and 335i heat-soaks fast once boost goes up. The do88 ICM-350-S is a stepped-core aluminum replacement with continuous welds and 3" (76 mm) hose connections in place of the factory quick-clicks.

Core volume is 124 percent larger and frontal area 75 percent larger. On a 335xi N55 that was otherwise stock, do88 measured outlet air at 43 °C against 58 °C, and 13 hp more at peak with a Stage 1 tune. It comes with a 2.5" aluminum J-pipe that works with the factory charge pipe or any aftermarket pipe made for the factory J-pipe.

SPECS

• Aluminum stepped core with continuous welds; 3" (76 mm) hose connections
• Core volume: 15,517 cm³ vs 6,933 cm³ OE — about 124 percent larger
• Frontal area: 1,151 cm² vs 658 cm² OE — about 75 percent larger
• Airflow at 0.15 bar (2.18 psi): 498 CFM vs 354 CFM OE — about 41 percent more
• Outlet air temperature: 43 °C vs 58 °C OE (do88 testing)
• Peak power gain: 13 hp on a 335xi N55 with Stage 1 tune
• Replaces OE 17517540035, 13717590304

PARTS INCLUDED

• 1 × do88 ICM-350-S intercooler
• Reinforced silicone hoses
• 1 × 2.5" (63 mm) mandrel-bent aluminum J-pipe
• 1 × plastic air guide for the top of the core
• Bolts, washers, clamps and installation instructions

TECH RESOURCES

• Required extras: none — the factory plastic air guide is trimmed to fit the larger core, and the supplied top air guide closes the gap.
• Installation instructions (do88): ICM-350-S N54/N55 intercooler installation instructions (PDF)
• Installation notes: remove the front bumper, unclip the OE quick-connects, remove the OE intercooler and trim the OE air guide per the instructions, then fit the do88 intercooler, J-pipe and hoses.
• Pairs well with: the do88 N54 (TR-270S) or N55 (TR-290S) charge pipe.
• Tuning: pairs with the MHD Super License – BMW N54, MHD Super License – BMW N55 (E-Series), JB4 – BMW N54 and JB4 – BMW N55 (E-Chassis).
• No CARB EO is published for this part — off-road / competition use only in California.
• Price is for the item only; labor is not included.

PART NUMBER

• ICM-350-S — do88 Intercooler, BMW 135i / 335i N54 / N55

VEHICLE APPLICATIONS