Prototype high flow belly pan finished and tested
 

Here it is.
https://www.rx7club.com/forum/attach...postid=1202712
https://www.rx7club.com/forum/attach...postid=1202723
https://www.rx7club.com/forum/attach...postid=1202739 https://www.rx7club.com/forum/attach...postid=1202749
https://www.rx7club.com/forum/attach...postid=1202767
https://www.rx7club.com/forum/attach...postid=1202775

If you have looked at the stock belly pan here are the modifications:
1. The lower lip is extented by 2" and angled more aggressively to scoop up more air.
2. The upper panel is angled to create a larger front opening and to increase the airflow speed via ramming effect.
3. There are now 2 rows of upper panel vents instead of 1. 3 sets of 2 1" vent openings have been extended to 2 sets of 6", 5", 6" vents (more than 5x the original flow x-section). The vent angles are also modified to be near perpendicular to the radiator (increase the flow effectiveness)

The aerodynamics have been tested up to 150 mph. At highway running speeds the average water temp is 8-12 deg F lower. (depending on speed and ambient temp).

looks like you made it outta the same material as the fake vomit people use for gags.

would you be able to extend the sides so that it reaches behind the wheel? i don't know what that might do and how it affects it , but most japanese companys that sell the undersweep have it this way.

luigi

It looks like the first good belly pan besides the stocker. The flat sheetmetal ones are junk.

Did you make this part or have someone else make it? PM me back if you can.

Thanks,
Jeff

That's pretty awesome.
Looks like fiberglass.
What are your plans for production process?

It could be done, but not sure why you would want to. It would be kind of awkward, the sway bar is in the way (check the last picture).

I did the redesign, and a friend (familiar with fg work) did the mold work.

Depending on the amount of interest out there, we will probably run a set of 20 the first go around. The finished product will be shipped fully assembled.

AND the big question, to get cooler tempts it will cost only ??? fill in the blank please. ------------

Yes, what will it cost?? Sounds good to me so far though. I'm interested.

The price should be $120.00 to $160.00 plus shipping depending on the quantity of each run. The time should be around 10 working days from the first determined production.

Just a point of interest. For those who are interested in show car items, we are going to have a carbon fiber (clear epoxy resin finish) version for $250.00

are you able to make one for people with FMIC's etc? or would that be a huge pain considering having to make the another mold. I ask because normall the radiator is in a different position from stock.

Danny

Nice job. Good to see people developing new products/different ideas for our cars.

HAHAHAHHA! What a piece of shit!

It sure is great to know there are some novice engineers (or should I say Profiteers?) that are ready to selll anything to anybody in the name of performance.

I guess Trex, this guy, is smarter than the Mazda engineers..........with their wind tunnels and cad cam stuff - even in 1990. Jeez, Mr. Chin, you really should check this out!

Tested to 150 mph? In your dreams.

If ANY of you guys buy this shit you
deserved to be raped!

HAHAHAHA! Talk about "cobbled"! Best laugh I've had in months!!!

Add me to the list of people interested in purchasing one.

I guess PT Barnum was right.

Ron, I thought you were all about some ghetto mods.
Trex, I can't see that lasting very long. As many times as I've heard something smack or scrape the bottom of my car, that fiberglass will just shatter.

Dood, I AM. But I don't try to pretend they work at 150 mph and then try to sell them to noobs. But hey, it's a free country and god bless all the hacks.

BTW, if you looked at my car, from ANY angle you would never know anything is Ghetto. (OK, maybe the exhaust if you crawled underneath)

I'm not trying to flame this guy, but you need to have somewhere for all of this "extra" air to go to make it work. Although my experience in aviation and laminar flow dynamics is rather limited to 22 years as an Airframe and Powerplant Mechanic and two plans built airplanes from scratch under my belt I still have a lot to learn.

Oh, what the hell. I am flaming him!

It's always funny to see idiots come to life on this forum. First of all, I do not claim to be smarter than the Mazda engineers, but then again, it's the same engineers that made the plastic ast that breaks apart and a precat that acts like a turbo heater. That been said, I'm sure there will be plenty of people with nearly a decade of experiences on the FD who will love to support your devotion to the perfect Mazda engineers. Oh have you also told Pettit how stupid their aluminum ast is yet, or Greddy for their rediculous one piece elbow. Is
The stock air channels in the belly pan was designed to provide sufficient airflow for STOCK configuration and nothing more. As anyone who have done the fmic mod will tell you, there is sufficient increase in the airpath resistence that the stock radiator position will no longer provide enough heat dissipation. Therefor, one common solution is to move the radiator to a vertical position, as required by all FMIC kit manufacturers (Apexi, Blitz, Greddy etc.) or are they all stupid as well, since they are tell you to move your radiator, contrary to where the Mazda engineers have placed them? For those people who prefer to leave the radiator in the stock position the reduced air flow is now a problem. The solution, increase airflow from below the radiator.
By the way, I hold a BE EE from MIT and MS comp sci from Princeton and currently working for Honeywell as a senior software control engineer, so don't tell me about "their wind tunnel and cad cam stuff", what is your almighty engineering background in making such a rude and crude rebuttal to the novice engineer?
I welcome any constructive criticism in my design modifications. That is how things get better, that is also why there is always an engineering team working on a design. Read through the original post and agree or disagree with each of the modification points, provide logical reasoning for the disagreement. But refrain from making juvenile comments on something you know nothing about.

I will answer your question. First, I had the car up to 150 mph, so has many others. I had to take the car up to that speed to make sure that there is no adverse lifting effect caused by pressure build up. And as you so fondly pointed out, I don't have a wind tunnel in my garage.
Second. If you bothered to read through the original post (line item 3.), the larger opening that collects the "extra" air is redirected through the larger (and extra) vents which are 5x larger in surface area than the stock vents, toward the radiator (isn't that the whole point of the exercise?)

As I have already stated, this is a PROTOTYPE, it has not been prettied up. There is such a thing called paint.

What does an Airframe and Powerplant Mechanic do? Design & engineering work, or is it the airplane equivalent of a general car mechanic?

Not sure what you run over. The prototype have been on my car for over two months and 1800 miles. I have driven over everything from the interstate to gravel. Given the direction of travel (since velocity is a vector, x being the horizontal running along the direction of travel, and y being perpendicular to the road surface) any object with enough force to crack the belly pan would have to come from extremely high velocity impact (lower velocities cannot create enough kinetic energy to inflict such damage). At normal highway speeds ~ 70-80mph the vertical velocity would be no more than 10~15 mph, that is not near enough force to crack the belly pan. I will however, concede to scraping, that is unavoidable. I have studied my own stock belly pan and I can assure you, there are plenty of scraps.

Although I applaud your efforts, I am always leery of mods that are done which may adversely effect the aerodynamics of the car at speed.

Driving the car at 150 MPH and noticing no changes in the steering or handling may give the impression that the car is safe with the mod at speed but what would really convince me is if you had some numbers on lift. I do not believe to measure lift a wind tunnel is required but it would require a fifth wheel with a device which can measure downforce(I am not sure what the name of the device is or how much it would cost to rent or buy).

[QUOTE]Originally posted by Trexthe3rd
[B]

I will answer your question. First, I had the car up to 150 mph, so has many others. I had to take the car up to that speed to make sure that there is no adverse lifting effect caused by pressure build up. And as you so fondly pointed out, I don't have a wind tunnel in my garage.
Second. If you bothered to read through the original post (line item 3.), the larger opening that collects the "extra" air is redirected through the larger (and extra) vents which are 5x larger in surface area than the stock vents, toward the radiator (isn't that the whole point of the exercise?)

Look man, I don't begrudge anyone doing prototypes of anything - it's all good fun. But just exactly what is the exercise here, more cooling? You can only "ram" so much air through the radiator fins, and then they cavitate and become less efficient.

Flow dynamics is a tricky and strange science, even with a wind tunnel and super computers.

I guess my problem is that you are quoting prices for your finished "product" already, and you are sucking along lots of guys in the process who think this will make them go faster, run cooler and be cooler - for a price.

But, like I said, I've got a lot to learn.

There is nothing but road construction, and chopped ass roads wherever I drive these days. When my car was new to me, I went over a few speed bumps that caught me off gaurd, and smacked the hell out of the frame rails. Everything was alright, but that would have been enough force to crack fiberglass.

I do not have the pressure roller for testing the down force differences between stock and my modifiec belly pan. I am also wary of the adverse effects on the aerodynamics of the car, that is why I could never agree with any of the other belly pan mods that have come along. I took the car up to 150, and felt no steering degradation. I have had slight wheel misalignments and caused the car to be wobbly at 120. This may not be the be all and end all prove, but for me (not planning on making too many 150+ runs down the interstate, not sure how many of you are?) it is sufficient.

I would have to say that all the track guys (and I thought you were one of them) are interested in any ways of keeping the engine temp down. All the road race guys see at least 140+ regularly on long straights.