Yanje

Ok, i know that many body kits enhance the aero dynamics of the car's body..... but most would be a little bit heavier, right?

I'm just wondering does body kits such as MS slow u down (street racing, or drag racing)?

titaniumgrey

the bigger hole in front gives the engine better cooling , so maybe there is an advangtage , I don't know , just my opinion. But I know kits from mugen are wind tunnel tested.

RX8Bliss

i have never known a body kit to be performance unless it is significantly lighter than the stock body. some argue that its more aerodynamic but you'd have to be travelling mighty fast for you to even notice any difference. in fact there are quite a few kits outthere that make the car less drivable after you install the kit - ie. more vibration, more noise, etc.
the ms kit imo is more looks than anything else. i'm sure the spoiler might add some downforce and the front might help the cooling, but the car will never be driven fast enough to use the downforce and the cars cooling is decent as it is.
most kits are for looks anyway. otherwise performance bodykits should be onepiece carbonfiber. man, that'd be just awesome and super expensive

dcfc3s

Of all the kits out there, I would reckon the MS kits would be functional and look good at the same time. I know the kits they made for the 3rd gen were wind tunnel tested - there's even pics of it floating around.

The majority of body kits are simply made to look neat. Aerodynamics is a VERY picky science, and most companies aren't going to invest a lot of time and money into that - much easier to sculpt something that looks good and get it out the door.

I do know that Steve Kan had a Veilside kit on his 3rd gen back in the day - removing the spoiler added like 5-10mph in the quarter mile, so it was definitely adding drag up top.

Mazda traditionally has done their homework when it comes to aerodynamics.

Dale

Gord96BRG

Actually, VERY FEW of the body kits out there enhance the aerodynamics of the car. The larger grill openings increase drag - the purpose of a larger grill opening is to increase cooling of the engine when you're generating more heat than a stock engine. Air flow through a radiator and engine compartment is always 'dirty' as far as aerodynamics are concerned - you want as little airflow going through as will provide just enough cooling, and no more. So much for nearly ALL the replacement bumpers, including MazdaSpeed's! The side sills may have some airflow benefits - but only if they're properly wind-tunnel tuned, otherwise they can just as easily cause more drag and disruption of the airflow than reduction. Since it's highly unlikely that anyone except perhaps MazdaSpeed ever puts their body kits in wind tunnel, that leaves out almost all the kits as far as side sills. For wings - a lip spoiler can reduce drag and 'spoil' some of the rear lift over the car. A wing almost always results in increased drag, but will provide some small downforce (actually, it's just a reduction of lift - no wing will actually overcome the rear lift to the point of providing real downforce).

In terms of slowing you down - in a straight line, more drag always slows you down. All of the body kits will slow you down. Going around corners - reductions in front and rear lift will improve handling, so there's the trade-off for the higher drag slowing you down on the straights.

Regards,
Gordon

bureau13

I doubt the SpeedSource racing team would be using the MS kit if it didn't help in some way.

jds

Japan8

Actually... both in the Mazdaspeed brouchure from the dealer for the 300 car limited edition and in the review of the specifics of it in the RX-8 Sports Magazine it is clear that the aerodynamics are significantly improved. The designer of the MS kbodykit is the original head designer of the RX-8 exterior. The entire MS kit has been wind tunnel tested and inaddition to better cooling it provides better downforce. Yes even that new rear-end is giving some aerodynamic benefit!

Yanje

hmmm. thx for the input guys, appreciated that..... still pondering whether to install a M.S. kit.

thought the kits do more than just better looks.

Gord96BRG

That's exactly what I said (I also said that the MS kit is probably the only one that's seen the inside of a wind tunnel). Better cooling, more drag. Downforce always is at the cost of more drag. In a straight line - downforce doesn't do anything for you, drag hurts you.

The SpeedSource racing team could be using the MS kit because they're getting paid to use it, but also because they find the trade-offs for better cornering are worth the higher drag. They go around corners much harder than any of us on the street do, you know! In terms of street racing or drag racing (the original question) - those are straight line acceleration contests, and any body kit will just slow you down. Even if it's just a small degradation, they most certainly will not make you faster!

Regards,
Gordon

JSE RX-8

yea there will be some extra weight on the car but when it comes to drag racing, the car stock doesnt put out great numbers on the track. you can easily make up the weight by putting on new tires and rims and added some N/A mods like an intake and exhaust and headers and downpipe. that could even the weight but i may be wrong. either way, track time isnt going to get any better unless you F/I

epitrochoid

spoilers can provide downforce, just as the wings on an airplane generate lift. they say some f1 cars can drive upside down over 200mph. even the awful wing on a wrx sti bends down at high speeds from the force.

Gord96BRG

Depending on wing configuration, an F1 car generates enough downforce to drive upside down (say, in a tunnel) at as little as 80 mph. Total downforce at higher speed can be as high as 3000 or 4000 pounds (the car by itself weighs 600 kg, or about 1320 lbs). BUT the coefficient of drag for a high-downforce config is over 1.5, whereas the stock RX-8 Cd is around 0.3 - ie the F1 car would have 5 times as much drag. Even in a low drag, low downforce, high speed wing setup, the F1 Cd is still about 0.9 (3 times the RX-8). Consider that a McLaren F1 ROAD CAR could hit 240 mph with ~600 hp, yet a McLaren MP4-19 Formula 1 racer (with a much smaller frontal area) needs 900 hp to hit about 220 mph in it's lowest downforce configuration - the Formula 1 racer needs much more power to overcome the much greater drag.

So - as I pointed out earlier, downforce doesn't come for free - it (almost) always comes with more drag. Since the force from aerodynamic drag increases with the square of the speed, it takes much more power to move your car through the air at the same speed if you're running more downforce/drag. Downforce slows you down in a straight line.

Regards,
Gordon