Reverse the airflow in L400 intercooler?

[tonydca]

Based on the performance recommendations of several forum folks, I'm looking to replace my flexing fabric-esque intercooler air hoses on my L400 with some solid (metal) ones.

The existing fittings on the intercooler are about 1-5/8 to 1-3/4 inch ID, and getting custom tubing made and bent to shape to replace exactly the existing hoses is looking like it might be a bit costly/tricky.

The current airflow path runs out of the turbo housing, thru one hose into the bottom of the intercooler, then from another hose out of the top of the intercooler into the intake manifold.

I was noticing however that I can run up out of the turbo and into the *top* of the intercooler with just a single 90-degree bend.

Similarly, if I judiciously use a few short segments of the existing hose, I can run from the *bottom* of the intercooler to my intake manifold with a second 90 degree bend.

The net result would replace about 90+% of my intake hoses with metal, using only a pair of $19 2" mandrel-bent EMT conduit pieces from Home Despot. Schweet!

Functionally, however, it reverses the flow of air through my intercooler. I can't think of a reason why this would be a bad thing to do, but anyone else think otherwise?

Thanks,

Tony.

[mararmeisto]

Fluid dynamics: the muffler or resonant chamber at the intake would not function properly and you'd have disrupted air flow and greater noise from the engine bay.

Difficult dismantling: unless you move the fuel filter, it is going to be EVEN MORE difficult to change the fuel filter with hard tubing instead of flexible. You'll have to completely disconnect the intercooler instead of just moving it to the side.

Limited performance increase: not sure that hard tubing would give that much of a performance boost over the soft tubing. At only 125hp, the losses in the tubing are probably nominal.

Positioning: greater performance would be achieved with hard tubing AND relocating the intercooler from the top of the engine to the front. Look at the example of any sports car to see the intercooler is at the front, perpendicular to vehicle-travel, not ABOVE the engine where all the rising radiant heat from the engine is going.

[tonydca]

Fluid dynamics: the muffler or resonant chamber at the intake would not function properly and you'd have disrupted air flow and greater noise from the engine bay.

Difficult dismantling: unless you move the fuel filter, it is going to be EVEN MORE difficult to change the fuel filter with hard tubing instead of flexible. You'll have to completely disconnect the intercooler instead of just moving it to the side.

Limited performance increase: not sure that hard tubing would give that much of a performance boost over the soft tubing. At only 125hp, the losses in the tubing are probably nominal.

Positioning: greater performance would be achieved with hard tubing AND relocating the intercooler from the top of the engine to the front. Look at the example of any sports car to see the intercooler is at the front, perpendicular to vehicle-travel, not ABOVE the engine where all the rising radiant heat from the engine is going.

I like your input. My thoughts are:

- I am unaware of any such muffler/resonance-tuning setup on my vehicle, but interesting point. Downstream of the turbo, there is just hose/intercooler/hose/intake manifold. As far as airflow disruption, I'd think any laminar qualities would be shot to hell by the internals of the intercooler anyways.

- Fuel filter removal - good point; I was actually more concerned about making sure the air filter was still removable. I'd be attaching the hard tubes with a pair of worm gear hose clamps, so not that much more effort to just pop them off

- Limited gain. I have no benchmarks to argue this, but want more to make sure that the hosing isn't limiting the quantity of air available to the engine. Increasing the ID of the air hoses from 1.625" to 2" allows for a hair over 50% more airflow. I'd still be limited by the size of the fittings on the intercooler/turbo/manifold, but I'm figuring it wouldn't make things any worse.

- Positioning. I agree 100%, but I don't know if I can suqeeze one in down there. I'll have to have another look...

Cheers for the thoughts - I appreciate the feedback.

Tony.

[madmazda]

I did mine in copper piping,,,, the upper one MUST be done in 1.5 inch piping as the wiper arms will touch anything larger.... I did the longer on in 2 inch copper piping as well and what a difference in power.... highway speeds the ole girl just ticks away now just waiting on my k and n filter to come next week then I'll be good to go