2006 Civic Coupe Aero Mods

[JacobLeSann]

Noted. Never thought about trash bags.

+1 on Temperature gauges. It’s kind of off-putting reading some of the earliest “grille block” threads on this forum where they just rely on the OEM coolant gauge and call it a day. I’m pretty sure that’s part of how I blew my first engine. Heck, I noticed my civic’s gauge doesn’t show any difference from 79-110 Celsius. Misleading.

[JacobLeSann]

Latest prototype. In my head, I’m imagining the front of an S2000, but in reality it’s not as nice. I still have no magnehelic gauge, so I plan to use tuft testing as well as playing with the car to see how high coolant temp rises. It’s already winter here which doesn’t help my testing.

After saying I’d leave it, I instead shaved the edges down on the ductwork. Reasoning? aerohead said so.

[JacobLeSann]

freebeard, do you know anything about the radiator design on a VW XL1? Perhaps somebody has seen the car in a museum or something? It looks like it’s designed to vent radiator airflow right out the bottom.

[freebeard]

Not a VW that I have owned

It appears to be as you say. You can see a duct in the underbody that feeds the vent.

What I find interesting are the pieces that shroud the wheel wells. 11, 16 and 27 are obvious, but 41 is on top of the bally pan so ????

[JacobLeSann]

Quick tuft test with “nose job” bumper and the original coroplast undertray I made. Looks very good, I didn’t see any issues although my camera is rough. With this setup at 100 km/h, my water temp was holding at a consistent 86 degrees Celsius.

I did a test on the same route in the same weather, after removing the undertray. This brought water temperatures up to a consistent 88 degrees Celsius.



I pulled over quickly and stuffed my sweater in the radiator duct. Back on the road at 100 km/h, the water temp began to slowly rise, and then it peaked at 103 Celsius before the fans kicked in. I pulled over and removed the sweater. The fans were able to pull air in and lower the water temp.

The ductwork seems to be functional, using the testing I have available. It is currently -3 to -5 Celsius outside. I noticed only one mystery in testing, and that was my intake air temp rising quite a bit. I wonder if the intake box is designed to pull exhaust air from the grille.


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The car is on the lift now, as I’m doing maintenance/checking before another big trip. I took some brake drum plugs off my parts car and realized that it has some underbody paneling. Sweet! That should be plug and play.



(Upside down, whoops)

For comparison, here’s the rear underbody of my car:



Improvable? I’d say so.

[JacobLeSann]

Driver’s rear wheel well. I made a very solid corplast structure to fill in the bumper gap behind the wheel, which improves the OEM rear undertray.



Passenger’s rear wheel well. I did the same job, but this time I gave good space for the exhaust pipe and muffler. When I first modified a car’s underbody, I had covered the whole exhaust with aluminum flashing. I didn’t exactly feel any issues, but it was a gamble of carbon monoxide poisoning and overheating. This time I’m leaving it open. There are two 10mm bolts in the frame rail, so I used those for mounting.



A laid-back photo of the ensemble. Both structure are as solid as the OEM undertray, and I did not make any holes into the unibody.


What’s next? Rear extension/separation edges? A diffuser?

Time will tell.

[aerohead]

HONDA used to shoot for 100-F year round, to aid fuel vaporization. A thermo-vacuum valve would operate the air bypass valve above the metal chimney, surrounding the exhaust header, which makes the hot air available for mixing with the 'cold' air charge entering the snorkel to the filter element, from its 'ram-air' entrance in the radiator bulkhead.

[aerohead]

If you want to, you may completely wrap the entire exhaust system with insulation of your choosing, and then install a 100% belly pan and diffuser.
Dr. Teddy Woll, of Daimler-Benz/ Mercedes-Benz has advocated for this.
Mercedes won't do this, on account of cost, and potential 'challenges' when servicing ( under warranty ) a 'production' M-B ( Code for fewer corporate profits, if they were the only automaker to do this ).
You're not constrained by outside 'bean-counters.'

[JacobLeSann]

aerohead,

I don’t understand fully what you’re saying about the cold/hot air temp mixing in the inram system. I’ll report back once I fully get it.

As for your second post…hmm…I suppose it is possible to cover it up. My main goal with this design is *not* to drill holes into the unibody, so I want to see how much I will end up covering up. If it is doable without much cost/effort, then I may just go ahead.

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P.S.

I plan to make a large separation edge horizontally along the bottom of the rear bumper. I’ve noticed that on most ultra-aero cars that the rear diffuser doesn’t come out far from the bumper surface. Is the a pedestrian safety thing? Is it a pointless endeavour? I can provide images to better explain my question.

[JacobLeSann]

Here’s my current progress. I’ve finally found some appropriately priced aluminum rivets. I took two undertray panels of my 2009 coupe and made them fit. Coroplast panels are riveted to these two pieces, and zip-tied to a few holes I drilled into the flange on the rocker panels. I figured there wouldn’t be any issues drilling into this area.