When I first purchased my Rx-7, about 3 months ago. (What a glorious summer this has been) it had no radiator ducting whatsoever. The complete undertray was removed in the suspected addition of a new front bumper.

Not knowing much about cooling theory, I figured that this lack of ducting wasn't really a big deal. A few weeks later I met Andy (GooRoo) and Damian (Damian). I soon learned the potential heating problems I would face if I ever wanted to take my Rx-7 to the track! (For those who don't know, it's nearly impossible for any non-track Rx-7 owner to see Damian's setup, and not instantly want to start tracking their car.)

Long story short, with the help of Andy's "Shop" here in the Twin Cities, Damian designed and crafted a ducting solution for my Rx-7 on the eve before my first track day in Brainerd.

I'll cut to the pictures. I must first say that the car is pre-wash, so she's normally not that dirty.












And here is a short movie that gives you a walk around of the ducting.

http://www.bentarnowski.com/Rx-7/undertray/MOV01959.MPG

At first I was really sad when I learned that we didn't have any big Rx-7 shops in Minnesota. I don't feel so bad anymore, because with friendly guys like Damian and Andy, I'm confident that I have more expertise near me then I will ever need.

I'll let Damian chime in with his comments about the materials he used if anybody is interested. Expect the same quality when he starts producing his splitter combo in the coming months.

-Rotary for the win

 

Wow, that looks very functional. Glad to hear things are moving forward, Ben.

I've been lazy about doing this and need to work on sealing off my radiator better. Good job!

 

very nice!

 

Badass. Great job!

 

so have you noticed your temps better on the highway?

 

Great post, video and pics! Thanks!

 

that looks great!! thank you for the ideal, i'm goin to try that on my seven
Timmy

 

My temps on the highway are so low that I thought my gauge was installed improperly. I notice a HUGE difference. The only problem is I installed my temp gauges post-ducting, so I don't have a good idea of what my real numbers were before. I'll record some numbers tomorrow on the drive to work.

-Rotary for the win

Here is another pic of her all cleaned up and waxed after my ducting photo session.

 

looks good, I will be doing the same with my v-mount this winter when I install my oil coolers....I just need to find a place that sells aluminum sheets here in AK...

 

Wow that looks pretty good.

I need to fab something up for my setup too.

 

Good job! Just think how much cooler things would be if you had a vented hood.

 

What material did you use? It looks like some type of laminate.

 

i am deffinatley interested in some details on this. looks Great!

 

Did you put some foam in the opening on the passenger side where the piping is?

Tim

 

Great job

 

Great project, I want to do the same!

I have another idea, why not add a piece just behind the radiator down to about the swaybar level to create a low pressure zone behind the rad to help pull air out (see pic)?? Good idea? I saw it in another car's custom ducting project and they tested the temps and it helped.

 

nice job! looks like you guys got this down pat!

 

Bad idea. All that will do is create drag and turbulence, not a low pressure zone. By smoothing out the airflow under that area, he's already helped create something of a low pressure zone in the area behind the radiator. You help create a low pressure zone (I say "help", because that's not all that's involved) by speeding up the airflow over the area, not slowing it down.

 

Well I thought a raised edge would create a low pressure zone right behind it. That's how most vented hoods create a low pressure zone to pull air out, by having a raised edge right before the actual vent.

Maybe in my drawing it appears too big, could be just a little lip. Besides, the swaybar and related hardware are right there already creating turbulence...

 

A low pressure zone is created by airflow moving faster over a given area, but there's a lot more factors besides that. The airflow moving over the curvature of the hood (if it's smooth up to that point) is enough to create a low pressure zone over the vent. These vented hoods that have a "raised edge right before the actual vent" are just for appearance.
So then what difference will a "little lip" make if the swaybar and related hardware are already in the airflow creating turbulence?

 

With a dedicated duct supplying ram air from the front of the car to the radiator a lip under the radiator would be useless for cooling purposes.

My stock front end and stock radiator cool very well with nothing other than fences added to the sides of the nose inlet so that any air entering the mouth cannot escape without passing through the radiator. Cheaper and more effective than just bolting in a bigger radiator as everyone always insists you must.

I experimented with a large forward extending lip as well and it also improved cooling but I don't need it except for the hottest of track days (100+ degrees).

 

These temps were recorded about about 40 mins of highway driving this morning.



Also, I ran into a little American muscle on the way home. This guy got a big thumbs up. We were only able to play for about a mile or so due to traffic and reasonablness. Forgive me for having to put the camera down to try to catch him!

http://www.bentarnowski.com/rx-7/undertray/MOV01968.MPG

My next step is to put up some bug guard type stuff to prevent too much from being sucked into the opening!

-Rotary4tw

 

damn my temps seat at 180 but its also a autometer gauge so it might be off but i'm going to try this ducting tip. thanks man helpfull post

 

Rotary4tw - i think your tstat might be stuck open or possibly modded with holes.

 

This may be the case. Right now my sender is mounted on the top of the housing, so the readings may not be 100%. I'm planning on threading a new spot down where the automatic sender is located.

I did let the car sit the other night, and watched the temps rise. When it hit 210, the fans came on, so I know it's accurate.

I'm also hopefully installing a PFC this week, so I should have something to cross reference the water temps with.

The oil temps stay pretty low unless I'm sitting around a lot or doing some really spirited driving. The other day in traffic outside the metrodome on a Friday night I was sitting at about 210 d for both water and oil.

I'll keep you posted on the PFC numbers when I get her operational.

-Rotary4tw