FWD and rear wings, a road racing question.

It's something that's been in even more question since the 2001 release of "The Fast and The Furious" and the global impact it had on the import/sport compact scene. 19 years later and tuners are still throwing massive wings on everything they can get their hands on. The time attack crowd....well those autox folks that are still too scared to go W2W racing love them even more than the tuners.....

Anyways....my knowledge of fluid dynamics and aerodynamics is about 3 on a scale of 1-10. There are opinions all over the internet on whether or not FWD cars need rear wings or not. My question is, what is the best style wing for a FWD endurance racer? We currently run this mid-80s NASCAR style plexiglass lip spoiler that we can make minor adjustments to. I honestly feel the aero drag outweighs any cornering benefits that might be seen from this. Does a FWD car with 200whp need a rear wing? If the answer is yes, what's the best style to go with? 

We've seen some benefits with the front splitter as it has helped with diverting air into the brake ducting and we see much cooler brake temps during pit stops, brakes don't cook themselves, and less fade over long runs. 

In the mechanical grip department, I try to keep things in the rear loosey goosey. It helps with rotating around a corner and reduces the fwd plowing effect (which the CD5 chassis doesn't really suffer much of). 

We never had any lose rear end problems with our 220 hp 3000 lb SHO, in 10 years of Lemons, Champ, or WRL. It has stock body other than a cut out in the hood for radiator outlet. 

You're cost to benefit ratio might be not worth it, but I see straight line stability as the only real reason to run any wing. That means a wing with end plates on it. Doesn't need any kick ups, angle, or wickerbill, just end plates. You'll be amazed as how much the car picks up because you're forcing air over the profile and just not letting it go everywhere.

Yes, they'll benefit as long as you plan on going around corners. "FWD cars don't need wings" is only looking at one part of vehicle dynamics, and that's the odd case of a car struggling for traction under acceleration while going fast enough to get the aero working.

Trunk mounted lip spoilers are a pretty high drag way to make downforce. A wing would be a lot more effective. Get a real wing (I don't know what "style" that is, but they don't sell it at Autozone) and start cranking in downforce. At the same time, work on the front end to keep the car balanced. When lap times start going up, stop. This has been going on since well before F&F, it's been going on since racers discovered that wings make cars faster :)

 I set my aero up to have a little more rear downforce and then set the car up to be a little loose with mechanical grip. Makes it easy to rotate in slower corners but stable in high speed corners.

Ranger50 said:

You're cost to benefit ratio might be not worth it, but I see straight line stability as the only real reason to run any wing. That means a wing with end plates on it. Doesn't need any kick ups, angle, or wickerbill, just end plates. You'll be amazed as how much the car picks up because you're forcing air over the profile and just not letting it go everywhere.

A wickerbill is a bit of a cheat, it's a way to get more downforce without a big drag penalty. Or, turn that around and you get less drag for the same downforce. "Angle" is a fundamental part of tuning a wing.

You're basically just looking at a wing as a drogue chute. It's not :)

FYI, the wing on my car was worth 2 seconds on a 63 second lap with a 45 mph average speed. Most of that gain was on the high speed sweeper which is almost exclusively about lateral grip and not about the ability to put down power.

Dayum Keith, how'd you know I purchase all my racing parts from Autozone? 

You're also right in the fact that F&F had little to no impact on the increase of wings/spoilers on FWD cars in the early 2000s. Do you think if I put a rotary wing on the top of my car and ran it in the opposite direction of the leading edge would I gain some downforce that way? 

Joking aside....this is what we're currently rocking.  We've got the mechanical grip part sorted. It handles very well with the double wishbone, LSD, and spring/shock upgrades. There is very little understeer for a FWD car and the big rear sway bar helps rotate the car. If we can gain anything in the aero department through a different piece of hardware....well that's the knowledge I'm looking for. 

Hmm, a reverse autogyro. Now that's an interesting concept. I'm surprised it hasn't been done in Lemons.

F&F definitely had an effect on tooners in the early 2000s, but I don't think they affected racers. Racers already knew :)

So, yes. I think you can gain quite a bit of grip and possibly less drag by putting a proper aerofoil on there. The old Car Of Tomorrow wings were a bargain for a short period of time, but the supply dried up. 9Lives will probably sell you a chunk of extruded wing, or you can even DIY one as has been done at several levels on this forum already. You'd probably have to extend the front splitter and possibly even add canards to get the balance you want. 

In reply to DirtyBird222 :

What's the height [and width] of that spoiler, and the angle you usually set it at?

Also, what track/configurations do you generally run at?

{edited to add a dimension request}

Dirty Bird: You could use the hardware on the car to start doing the cost benefit number crunching. At your next event - If the spoiler is adjustable, document the angle and run a few laps. Then bring the car in adjust the angle up/down ~5degrees, and run a few more laps. repeat until one of the following happens: You run out of adjustment, the car becomes undriveable, or you get tired of pitting and adjusting. Collect all your angles/lap times/driver comments in one place and plot it up to see if you can see any trends. If the car get undriveable because of lack of front grip, but your laptimes are still getting better, then you need more front downforce to balance it out (and the car will get faster again). You are going to sacrifice some laptime to collect all the data, but you cannot really start figuring out how to optimize the car without some sort of simulation, and the cheapest simulation you can do with a car and hardware you already have is to run laps.

The general trend is toward more downforce, because you are increasing you average corner speed, without making too much of a dent in your top speed. That results in lower laptime/faster lap average speed. Even a simple deck spoiler like yours provides enough downforce to make the car faster in the corners. The real trade off is that you will now start moving down a path that requires more work/planning/spending to make the car "better".

If you really want to start getting some numbers for the aero impact of your changes. have a teamate time the car through a segment of the track with lots of cornering time. You will see a significant change in cornering times as the settings are adjusted. If you have the track layout data and a good long corner (like Keith mentioned about his local track) you can work backwards with some approximations to get the grip change and then the effective aero change.

I designed a pair of wings for JG's F500 car a few years ago using freeware/opensource and was able to generate a design that netted ~600 pounds of downforce on a 900 pound car at 60mph. Yes the aero can be significant, even at relatively low speeds.

Keith Tanner said:

Trunk mounted lip spoilers are a pretty high drag way to make downforce. A wing would be a lot more effective. Get a real wing (I don't know what "style" that is, but they don't sell it at Autozone) and start cranking in downforce. At the same time, work on the front end to keep the car balanced. When lap times start going up, stop. This has been going on since well before F&F, it's been going on since racers discovered that wings make cars faster :)

As it happens, I've actually been messing around with tweaks to an "generic aluminum amazon wing" to improve its performance. 

In reply to DirtyBird222 :

A rear wing is definitely worth it on an FWD road race car. You lose a few MPH down the straights but the gains through high-speed corners more than makes up for it over the course of a lap.

For reference, we took a cheap plastic copy of an APR wing, filled it with 2-part polyurethane foam, and put it slightly below roof height on the trunk of our 180whp Honda. The car went aorund 1.2 seconds on a 1:15 lap on NJMP Lightning from the wing alone. When we added the splitter it went even faster.

Also worth mentioning: As a good friend once said - "The setup that makes a FWD car dominate in auto-x also makes it terrifying at high speeds."

I'm no expert, but it stands to reason. You want the car to rotate in tight, low speed corners. Not so much at an 80mph "kink."

I drove my ZX2SR on several tracks at speeds up to 115mph and 60/90 moh corners with just the little factory spoiler and never felt any instability.