Underbody diffuser?
#1
Wobbles09
Thread Starter
Underbody diffuser?
Has anyone else seen one for our car or am I the only one doing this? I've designed one in 3dparticular and now progressing to a cardboard test model
#2
Wobbles09
Thread Starter
#4
Wobbles09
Thread Starter
No mine is a whole underbody in sections, I researched the perfect angle for the rear and such, spent a great deal of time taking multiple measurements. I can post pictures tomorrow when I get back on my computer. This is still in development but support would be appreciated lol
#6
No mine is a whole underbody in sections, I researched the perfect angle for the rear and such, spent a great deal of time taking multiple measurements. I can post pictures tomorrow when I get back on my computer. This is still in development but support would be appreciated lol
We modelled the diffuser with symscape caedium but had some problems finding the right angle\mounting points since the exhaust must be covered or "integrated" in the design. Since the first is cheap and the latter is not we obviously went for the first!
Looking forward to seeing the pics!
#8
Wobbles09
Thread Starter
Nice! Did you go for a 4pcs complete underbody? (front - center L\R - rear) That's what i've done.
We modelled the diffuser with symscape caedium but had some problems finding the right angle\mounting points since the exhaust must be covered or "integrated" in the design. Since the first is cheap and the latter is not we obviously went for the first!
Looking forward to seeing the pics!
We modelled the diffuser with symscape caedium but had some problems finding the right angle\mounting points since the exhaust must be covered or "integrated" in the design. Since the first is cheap and the latter is not we obviously went for the first!
Looking forward to seeing the pics!
#9
Space is your enemy here...
Think about the exhaust. Will the diffuser be underneath it?
Moreover, transmission and midpipe are on the way. It's better to leave them "Open", hence my 3\4 pieces underbelly comment![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
EDIT (Just read your comment)
9.5°? We ended up with an optimal angle of 12° but our idea was to use the exhaust itself as a hanger for the diffuser, thus making it "longer".
Very nice design anyway!
Think about the exhaust. Will the diffuser be underneath it?
Moreover, transmission and midpipe are on the way. It's better to leave them "Open", hence my 3\4 pieces underbelly comment
![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
EDIT (Just read your comment)
9.5°? We ended up with an optimal angle of 12° but our idea was to use the exhaust itself as a hanger for the diffuser, thus making it "longer".
Very nice design anyway!
Last edited by bse50; 09-10-2011 at 08:36 AM.
#11
Wobbles09
Thread Starter
All of the full underbody designs I came across had the entire bottom convered, there was a tunnel for the exhaust with a little extra clearance but it wan not "open". Leaving sections open would defeat the purpose of trying to enhance the airflow under the car
#13
Wobbles09
Thread Starter
My car has already been lowered 2.5 inches all around so i sit very low already, And this design was for me to show my skills and produce something I cannot find on the market. I have a few friends with 8's also that would be interested in it. If its successful I would like to market it. I have also toyed with the idea of using it to mold a cf version instead of having to weld all the features. Still, this design is only days old
#14
The fact behind my suggestion is that our exhaust runs extremely hot and already heats up the transmission above a "safe" point when tracking the car. Even a couple of naca ducts and exhaust vents wouldn't be enough! You might even start a fire there.
![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
Now I see the 9.5° angle anyway, my car is less lowered than yours.
#15
SARX Legend
iTrader: (46)
Nice work, I wish I could use Solidworks.
Rotr8 is working on something similar and sifu has a rear diffuser already but no rear under body.
It's a nice concept but encasing the exhaust in it is not a good idea. A rotary exhaust runs much hotter than a typical piston engines exhaust.
Edit: bse50 summed it up.
Rotr8 is working on something similar and sifu has a rear diffuser already but no rear under body.
It's a nice concept but encasing the exhaust in it is not a good idea. A rotary exhaust runs much hotter than a typical piston engines exhaust.
Edit: bse50 summed it up.
#17
Wobbles09
Thread Starter
If temperature is an issue, additional air ducts can be created and incorporated into the design and the 9.5 degree is just the angle of exit above horozontal, my car doesnt sit at that angle lol
#20
I know that your car doesn't sit at 9°, i just stated that my car sits higher than yours so i had to use a different angle (around 12°) to make the diffuser effective.
#21
SARX Legend
iTrader: (46)
![TX](https://www.rx8club.com/images/icons/tx.jpg)
Yeah, you are about the 500th noob to make that statement and never back it up. Besides Hinson is allegedly a bunch of crooks (busted for having stolen cars in their shop), I doubt that kit will ever be finalized.
#22
Wobbles09
Thread Starter
EDIT I'm not a noob, if they dont have a design I can go elsewhere, with an engineering background im sure i could figure things out if i had enought time. I do plan on putting a piston enigine in my car for multiple reason just like i do plan on having a fully functional diffuser shortly. I shouldnt have to defend myself haha
#23
SARX Legend
iTrader: (46)
![TX](https://www.rx8club.com/images/icons/tx.jpg)
EDIT I'm not a noob, if they dont have a design I can go elsewhere, with an engineering background im sure i could figure things out if i had enought time. I do plan on putting a piston enigine in my car for multiple reason just like i do plan on having a fully functional diffuser shortly. I shouldnt have to defend myself haha
Don't take noob as a negative insult, it's just what you are for now. Everyone was a noob at one point and for now you are still a noob despite your educational/work background.
I am sure you could figure things out but I doubt you will. It's just one of those things, people come in all the time saying they are going to do this and that and 99.9% of them never do ****. The piston engine into the RX-8 is nothing new but I have yet to see a streetable RX8 with a proper piston engine and I highly doubt you will be the first person to do so. The guys from Pakistan (why I don't know) have done some swaps but they are seriously lacking in power, and fit an finish.
Take a look at all the threads started about doing LS swaps and then show me one that is actually running and being driven. The only one I know of that was even close, was trashed.
Last edited by 9krpmrx8; 09-10-2011 at 09:23 AM.
#24
Registered RX8 Nut
iTrader: (11)
Any and all underpaneling will help, it doesnt have to be perfect. Obviously the more you can cover and the smoother the air flow, the less drag and more downforce you will produce. But at what cost? If you cover the entire exhaust, you will be in for a world of hurt.
Heat sensitive components.
1- Engine. You need to get hot air out of the engine way. This is usually done out the bottom. You can and should panel under the engine with a louvered panel. This will smooth out the airflow and help evacuate the air past the engine, into the transmission tunnel area. Beat rush makes a nice piece. A little pricey and a little heavy, but a good design. Notice the S2 rX8's have a under engine panel. Adding a vented hood also helps get heat out.
2- Transmission. As long as you get some air passing by the transmission, you will be ok. But if you panel from the engine straight back accrossed the trans and dont let it breath, it will get hotter and could suffer. I suggest Naca Ducts to bring in fresh air at the bell housing, louvers under the trans and naca ducts post trans.
3- Differential. Even without underpaneling the diff will suffer from excessive heat if driven hard in excess of 30-40 minutes straight. This is largly due to the close prximity to the exhaust pipes. My suggestion and plan for my similar project is to leave the exhaust pipes open. This will create a tunnel for the air to flow through and keep the exhaust from cooking the diff and the underside of the car. I might even suggest going one step further and where possible actualy creating a half tunnel around the exhaust to smooth out the airflow. When the exhaust moves to the center of the vehicle, under the driveshaft, you could leave it open or cover it and use naca ducts to let air in and louvers or naca ducts to get air out. As the exhaust passes near the diff, I might had a heat shield to protect the diff. Not sure how much room will be in there, but its an idea worth looking into. You could also panel around the diff but not directlty under it. Again, need to physicaly get in there and see what space is available.
4-Lastly, the mufflers. The issue I have here is that if you panel below it you will trap in the heat and cook your trunk and bumper. I have 2 ideas both envolve the existing heat shield above the mufflers. You can either leave everything open under the mufflers and connect the paneling the one side of the heat shield and the otherside to the diffuser, or you add additional heat shielding to protect you bumper and panel under the mufflers using louvers to help heat/air escape. I like idea #2.
I plan to use a small guage aluminum. Only needs to be thick enough that I can wield in naca ducts and louvers.
For my diffuser, I have just gone with the mazdaspeed rear. It might not be the perfect diffuser but it is an improvement. Additionaly, is rounds off and raises the bottom of the rear bumper. Something adding a diffuser to a stock bumper wont do.
I look forward to see progress on thse projects.
Last edited by Highway8; 09-10-2011 at 09:36 AM.