ourxseven

iTrader: (1)

i'm considering a body kit or lip while I get the '89 vert freshly painted and a little rust repair . I've searched the threads and found lots of opinions on the looks and fitment , but nothing really on the effects on handling. I get the vert over 180 km/hr ( 110 mph) quite often and its stable as hell stock

anyone have any technical info or other experience on how these actually help or hurt handling ?? .......... or are they just all show

brooklynfc3s

iTrader: (1)

just get a front lip and some side skirts. the s5 rx7 was a really good looking car.

AWD-RWD racer

iTrader: (5)

i have yet to modify the body on my fd. but i did put a body kit on my 98 subaru (veilside) and it felt a little quicker, and it showed in my 1/4 mile time.

Black91n/a

It'll all depend on the kit chosen. More open area in the front will likely mean more drag, a lower airdam or the addition of a lip can help reduce drag and increase front downforce. It all depends on the kit chosen.

Madrx7racer

the exact details on the drag the kits cost but I like to use a bit of common sense:

i expect thiese kits to increase drag due to their surface area:






One could argue that the companies that made these kits took an increase in drag by these kits but that's would be an assumption on our part..........

I have this kit on my car and I chose it because it followed the stock lines but honestly I don't know whther or not drag has been increased......not all of us know or have access to a wind-tunnel to actually test anything out.





Mine:



Here is a stock front end for visual comparison




At this point very few ppl can claim any sot of airflow benefits from their body kits ( I know a couple of ppl that claim to have taken their car to a windtunnel) but for the most part it is an aesthetic modification............

I can claim that the larger brake ducts on my kit help more, or the angle of the kit makes me gain a bit of downforce at higher speeds but that would be an innacurate assumption.

So, to answer your question: no, there is no way to confirm or deny any aerodynamic benefits of aftermarket bumpers....let alone knock-offs.

SMonty

How much of a difference are you talking? did you remove bumpers? I highly doubt a body kit made your car faster. unless it the stock bumpers were 50 pounds heavier.

PvillKnight7

iTrader: (16)

all show- dont be a ricer, keep it stock

HeyITZthatFC

Don't think so.

Black91n/a

There can be soem real benefits from a bodykit, but most are mostly for show. Having larger openings is good for cooling, as you'll get more air going through the radiator, oil cooler and intercooler if you've got an FMIC. Having a lower airdam and a lip can gain you some much needed front end downforce (well decrease in lift).

My dad put a spoiler on his Mk I GTi and says that he noticed an increase in top speed (not that it was very high to begin with). It was pretty much like the S4 sport one, almost any wing or spoiler will increase drag though.

Flash

iTrader: (2)

This is all going to depend on what you buy. In Japan, they call their body modifications "Aero Kits"... while in the US they are more commonly referred to as "body kits".

I read an interview recently with the Owner of C-West from Japan. They own their own wind tunnel testing facility and they have proven that the addition of their kits increase down force and higher top speeds. I forget what track, but with a stock integra and the c-west body kit, they could reach 10 mph faster on that tracks longest straight-away. Basically they proved that with only body mods they increased the top speed due to better air management.

There is a really good book about the history of porsche, and in it they talk a lot about making the 911 stable aerodynamically. Obviously, the faster you go, the more your car wants to lift off the ground (your car is shaped like a wing, more surface area on top). They found that at over 150kms, the car was lifting up to the point of 100+ pounds up force in the rear and I don't remember how much at the front. So they redesigned the front end to create downforce and out a spoiler on the rear.

Then there is the JGTC series in Japan. In the GT 500 and GT 300 classes, the cars are restricted to 500 and 300 hp respectively. The cars are supposed to look as much lik the actual base car as possibly, but it is in these series where you see awesome aero kits actually in use. These are the real deal. It's these cars that the serious companies make their public sale kits from.

So yeah, if you buy crap from out of the back of a truck, you could have stock or worse performance. If you buy proven quality aero kits, there is a huge difference.

Madrx7racer

makes sense.....the only problem now is finding all this data...........and you have to also consider that the knock-offs ( like the corksport BORDER copy I have) might not be exact copies so the knock-offs might not have the same aerodynamic benefits as the original Japanese Front, sides and rear ends.

raptor22

A well designed body kit will decrease drag and, in some cases, give some downforce.

It really isn't that hard to create a nice lip and sideskirts that will improve performance...and small design changes really won't hurt much. Basically, the lip has 3 purposes:
-Keep air from going under the car...which decreases drag and lift
-Direct some of that air up into the radiator for better cooling
-Give you a little downforce by pushing air upwards

Although testing helps optimize the performance, any shape that does the things above will help.

However, the difference really won't really be too noticeable. A 10% decrease in drag and a bit more high speed stability would be considered a pretty successful result. Which means that, for most FC's, you would probably get an extra 10mph added top speed and an extra mile or two out of a gallon of gas on the freeway.

Where you really see gains is in a full body kit, properly designed underbody panels, and a really nice rear diffuser. If it were all tied in correctly, you would get quite alot of suction on the bottom of the car, and a considerable amount of downforce without any drawbacks.

As far as wings and spoilers go, the drag could go either way. Some of them help bring up the stagation point behind the car, so that the air flows more smoothly off the back. However, as a general rule, they add drag...and the bigger and higher the spoiler, the more drag it produces. On top of all that, most people that want a big gaudy wing don't even consider the fact that any downforce will only act on the back of the car, and may actually hurt the high speed handling.

--Alex

Madrx7racer

theclosest thing I have found for improved aero has been this:

RE-A rear CF diffuser and S4 wing


You can't go wrong with RE-A aero products.........I've asked shineautoproject regarding thier copies and if any kind of testing was done but I believe I was told they were exact copies.


Honestly this shouldn't be an issue until you're turning your DD into your auto-cross car.........

pengarufoo

Because solo2 autox really gets up there in mph making aero matter alot, you know those parking lots allow for some serious triple digits.

You'd be doing alot better thinking about the weight of the body parts rather than their aerodynamic effects if you're worried about autox performance.

Black91n/a

The biggest problem I see with body kits is the rear bumpers. A lot of kits have really low rear bumpers, and all that does is act like a parachute. It'd be better to close off the area under there, or cut a chunk out of it to let the air escape.

PvillKnight7

iTrader: (16)

You can easily go 10mph faster with any number of minor mods. RX-7s are made for speed and will not become unstable at 130mph. A body kit on a DD is rice.

RE-Amemiya

+1!

PvillKnight7

iTrader: (16)

oh...and screw mpg.

that is all

Black91n/a

That explanation of downforce generation is crude and inacurate. Front airdams, splitters and undertrays produce downforce by creating a low pressure area under the nose of the car, which "sucks" the car to the ground.

For lots of aero info look here:
http://www.advantage-cfd.co.uk/News/...-Releases.html

ourxseven

iTrader: (1)

thanks all, some good stuff in there

just a little better than ...... that kit looks hella sick

keep it coming, looks like a small lip ( like the mazsport S5 lip) might help and not screw up what the mazda designers did so well.