Cooling lines through tunnel Options

[East coaster]

I thought I’d give some real world feedback on my cooling lines (Subaru powered) I ran through my center tunnel. When researching this option I saw a lot of posts stating that it would add heat to the cabin and I was concerned about that, but decided I wanted to go this route and find out for myself.

I’ve now put about 500 miles on my car through some of the hottest summer weather I can remember and I have to say I have zero heat transfer in the tunnel. I didn’t do anything to insulate the tunnel itself, but I did insulate the tubes passing through it. I used 1-1/4” alum tubing for the runs and I covered the tubes with a quality pipe insulation from McMaster Carr. I used one piece of insulation and ran both tubes through it. This took up less room in the tunnel vs two individual pieces of insulation and just fit better.

Here’s the insulation I used:



Here’s the tubes as the enter the tunnel:



Well, I just wanted to post this for others who might be contemplating a through tunnel run. I was almost swayed from this based on what some thought would be a problem vs real world feedback from those who’ve done it. I’m not taking a shot at those who shared concerns, but wanted to give some feedback after running in some wicked summer heat.

[Craigers17]

So I'm guessing that since the Subi is a cable shifter, and the shifter is on a raised pedastal, that you no longer have shifter cables or wiring harness in the original tunnel area? (also obviously no more shift rod) How about fuel lines?.....are they still in the tunnel with the coolant lines?

I like the idea of routing the coolant lines through the tunnel like you've done....not only does it provide protection vs. being exposed under the car, but it also looks a lot cleaner. Very nice!

[East coaster]

So I'm guessing that since the Subi is a cable shifter, and the shifter is on a raised pedastal, that you no longer have shifter cables or wiring harness in the original tunnel area? (also obviously no more shift rod) How about fuel lines?.....are they still in the tunnel with the coolant lines?

I like the idea of routing the coolant lines through the tunnel like you've done....not only does it provide protection vs. being exposed under the car, but it also looks a lot cleaner. Very nice!

Correct, cable shifter. The cables and the harness both go into the tunnel at the rear where the tunnel flares out on each side. There’s room for coolant tubes, cables, and harness. My fuel lines run through the passenger side heater tube, so I’m not heating my fuel.