See, that's bad logic. The temperature close to the ground is always hotter than air two feet off the ground, unless the ground is frozen or wet or something. Heat radiates off of what is emitting it, that means that the hot air near the radiating body rises to a cooler region. Air further from the road is cooler than air close to it in dry conditions.

Agreed, which is why not having a splash tray will cause your ac core to get heat soaked quicker. I think a lot of it has to do with packaging, reliability, driving conditions, etc. Having it point forward will have it pull air that is not heated from the radiator area but will also make the air box get dirty quicker. Making a turn down into the bumper opening will avoid grasshoppers in the airbox, but could make for higher intake Temps.

My last tank was 17.7 mpg. That's a big difference but I also kept the traction control on the whole time.

Agreed, and two feet of the ground is somewhere near the top of my engine and the hot air radiating and rising off of your engine is much hotter than the air radiating off of the road, hence why the cold air intake drops below the engine bay closer to the road

The under tray keeps the hot air (been through the radiator) from sneaking back in front of it in slow traffic. This issue is also the reason for the foam around the radiator mod.

The lower pickup is because, at low speed, there is a trapped volume inside the nose that guarantees that any hot air will be sucked in first, either through the tube, or the VAFD opening.

Close to the grill is the coolest air. The Racing Beat intake is the best for this. It mounts to the grill. The rest of it is the subject to debate, but the Duct is a definite win.

I moved the intake pickup and posted the info on my site. It was getting pretty late after trying to fix my broken headlight and removing the light reflectors from my foglights so I basically used a subaru bracket and some 3" universal auto ducting to relocate the pickup. It really needs to be a little forward so it's not in the turbulent heat mess when the fans are on but even still, prior to this it wouldn't have been possible to see intake temps less than 15 degrees above ambient on the freeway.

http://www.uniquemotorsports.com/wp-...2-47-04-AM.jpg

http://www.uniquemotorsports.com/wp-...2-38-21-AM.jpg

http://www.uniquemotorsports.com/wp-...2-47-11-AM.jpg

Results: Highly recommend it. While there can still be a 40 degree spread between the outside air and the intake air, it’s overall much better. Prior to doing this, I would not be able to get close to the ambient air once the car was warmed up. Now it’s about 15 degrees over in flowing traffic and 25 to 30 degrees over in heavy stop and go in town traffic. One more thing to note is by replacing the "preheater" tube like this, I think the intake temps will actually improve with the VFAD reconnected.

Here is a link to the write up I posted on my site along with a lot more pictures.

Rx8 Airbox Mod – Lowering Intake Temperatures | Unique Motorsports

Thanks for the pictures, and especially for the temps. I need to start watching those again and see if the tubing will help over just having the box open and maybe re-directing air upwards..

Thanks again

Thanks for all your well done posts. I just got the 8 in march and still doing "fix mods". Your post regarding "congrats on the 8" has helped me a lot. I still haven't pulled the plugs, aside from that, insulating around the radiator and A/C reprogram, I pretty much did everything you mentioned. Fixing the threads for the ESS, I managed to scratch my cornea... wear safety glasses when taping threads under a car kids.

I'm moving into my new garage this weekend, I'll update this thread when I get a chance to modify the intake a little more. Most likely, I'll mount it forward a little so it's cool when the fans are on and hook the VFAD back up.

i updated this. Here are the highlights I posted on my site.

Changes I wanted to make

-Hook VFAD back up, allowing the main pickup to be the relocated intake
-Move the pickup tube forward a little so its out of the turbulent air produced by the radiator fans

Results: With the pickup moved, I now see the following temperature differences.

Stop and Go Traffic – Intake temps are usually 20-25 degrees higher than ambient.
Free flowing Traffic – Intake temps are usually 10-15 degrees higher than ambient
Freeway – Intake temps are usually ambient to 5 degrees higher than ambient

The bracket

https://cimg8.ibsrv.net/gimg/www.rx8...cce3e2f183.jpg

The bracket installed

https://cimg0.ibsrv.net/gimg/www.rx8...023a2aef67.jpg

The end result

https://cimg9.ibsrv.net/gimg/www.rx8...cab0c69003.jpg

don't hit any deep rain puddles ....

Nice... But I echo the deep puddle concern. Nice work on the bracket.

I don't see me fording any creeks deeper than 8 inches. If I do, I can floor it to initiate the vfad. It's also turned a little, behind the bumper plate to help keep out rain, dust, grasshoppers, etc.

It's not necessary to reinforce that you have no idea about the situation ...

Oh god, the damage that will do.

For some perspective, if you drive through a puddle at 4500RPM, your engine will attempt to suck in and compress about 100 liters of water into 10 liters of water in the span of one second.

Don't forget that water is incompressible.

That would be bad. There is no direct path though to the intake, it's not a ram air setup as it's behind a cover. I would actually have to submerge the entire front of the car at which point, the intake box is not perfectly sealed where it goes through the core support so it wouldn't be able to suck up water anyway.

Another interesting point about this is I moved it down and forward so it would be out of the turbulent air from the cooling fans. I have since installed a Koyo radiator and now when the cooling fans finally kick on, they don't create that turbulence of hot air in the front bumper opening.

I have my radiator all insulated with pipe insulation, heat reflective material on my intake and airbox, and a fully sealed up Racing Beat ram scoop connected to the stock intake. My intake temps are usually about 10 off ambient when driving around. Obviously when sitting still its going to go up.

Great write-up and pics for your handy work. I personally see very high intake temps but that it because I have an AEM intake that has to be a short ram, since the previous owner was in a front end accident and the support beam is bent backwards so I could not install the "S" curved piece that goes from inside the engine bay between the beam and the firewall and put the filter outside of the bay. I see temps of 143-149 while driving and then 150-160+ when sitting at idle with no airflow. I saw one up to 175 yesterday when the outside temp was 92 degrees out.

I just have the VFAD connected as it came, but with a short ram intake instead. I like this idea of the intake tubing/accordion style and planned to see about ripping out the VFAD system and capping the manifold and route my filter where it is supposed to be outside of the engine bay but use the accordion to wedge between the bent support mean instead of the metal piping that came with the intake. Would basically make it like yours but with a filter on the end of the accordian hole.