Intercooler bypass

donutV70 · Post by **donutV70** » 15 Feb 2022, 11:14

Hey guys, i had a small accident, everything is fine except the intercooler is cracked badly on the bottom.

I was curious what your thoughts were on doing a TEMPORARY bypass of the intercooler Ie. turbo directly to throttle body.

My situation is i am 4hrs from home and am able to get a used intercooler there for about 40 buck while where i am now a salvage yard wants 230.

My biggest concern here is high intake temps causing pre-ignition and damaging the engine

Post by **abscate** » 15 Feb 2022, 11:16

Maybe bypass and pull off the connector from the turbo control valve?

donutV70 · Post by **donutV70** » 15 Feb 2022, 11:20

wouldnt it be possible to overboost without the TCV?

Post by **BlackBart** » 15 Feb 2022, 11:55

Can you drive it 4 hours on very low boost? Very light throttle, stay out of boost where possible. Just limp it home. The intercooler is just working to lower intake temp, so if you're not loading it up, it could be you can avoid any detonation issues.

We once cracked our 850 intercooler, and it would barely run with an open system like that. Boost / no boost / extremely rich. 4 hours would be murder.

donutV70 · Post by **donutV70** » 15 Feb 2022, 13:47

BlackBart wrote: ↑15 Feb 2022, 11:55 Can you drive it 4 hours on very low boost? Very light throttle, stay out of boost where possible. Just limp it home. The intercooler is just working to lower intake temp, so if you're not loading it up, it could be you can avoid any detonation issues.

We once cracked our 850 intercooler, and it would barely run with an open system like that. Boost / no boost / extremely rich. 4 hours would be murder.

thats the thing this will hardly run so i dont think i could make it run long enough to limp it home without doing a bypass of the intercooler, are there any ways to force it into low boost or no boost?

Post by **Chuck W** » 15 Feb 2022, 16:36

Pretty sure he means to drive it easy with the IC bypassed.

You'll be fine with it bypassed if you keep your foot out of it.

Post by **abscate** » 15 Feb 2022, 18:12

I will let the turbo experts comment on this, but I believe the wastegate operates by the actuator applying pressure to hold the wastegate closed, if you disconnect the electrical, no pressure will hold the waste gate closed, and it will dump the boost, therefore running no boost!

to be confirmed, corrected by Chuck below

Post by **Chuck W** » 16 Feb 2022, 08:44

Boost pressure opens the wastegate. No boost signal keeps it closed which means all the boost. The recirc valve opens under vacuum, such as when you let off of the throttle while under boost. This allows the boosted air to be rerouted back to the front of the turbo, instead of having it slam into the closed throttle plate and then try and stall the turbo compressor wheel.

Just bypass the intercooler and drive it easy.

Post by **foggydogg** » 16 Feb 2022, 21:34

I'm really confused. If the intercooler is broken, doesn't that mean all the boost vents to atmosphere ?

Post by **BlackBart** » 16 Feb 2022, 22:14

Yes. The computer is completely confused, it will barely run. But if he can connect the upstream hose directly to the downstream hose and bypass the intercooler, it should run normally unless the intake charge gets too warm.