Which front diffuser goes with which wing and vice-versa?

We realize that it can be tough to match what rear wing goes best with our front diffusers or what front diffusers to get to match your existing wing. We scoured the internet for rear wings with publicly availably CFD data and used the information to match common applications. We made sure the CFD data provided made sense and made notes below when it was a little confusing. We are here to help.

Here are some BROAD brush strokes to help point you in the right direction. We’re assuming well-constructed splitters, moderate in size with our small diffusers and larger with our large diffusers. We’re assuming a 3-4″ splitter height. We’re assuming fender venting. We’re assuming no rear diffuser. We’re assuming a lot of things but the suggestions below will get you on the dart board. From there you can tweak to get that bullseye.

The most critical detail to note going in, weight distribution is most important! Your drivetrain layout doesn’t really matter, but these examples can be useful. Without further ado; read, enjoy and ask questions!

FWD: 65% Front / 35% Rear Weight Distribution

Small Front Diffusers

APR GTC-200: This little wing is extremely efficient and usable in this application. That being said, it will be at the upper range of its max performance, meaning any increase in front downforce will render the wing unsuitable. DATA

Nine Lives Racing Wang: The data provided by Nine Lives is a little sparse as width isn’t included in their figures. That being said, assuming the CFD is used on a large wing width, the downforce numbers are realistic and leave room for future aero upgrades. Especially when a Gurney flap upgrade is made. A good choice indeed. DATA

APR GT-250: The GT-250 is an excellent match in this application. Not quite as efficient as the GTC-200 but it will still have plenty of extra performance left for increases in front downforce. DATA

Large Front Diffuser-

Nine Lives Racing Wang: I think this wing would work well in this application with a larger Gurney Flap option. There would be a little headroom left for future upgrades. DATA

APR GT-250: The GT-250 is usable in this application with a little room to spare. Because using this wing would require it to run at a higher angle of attack, efficiency drops off slightly. With the Gurney Flap option, this wing is perfectly viable in this application. DATA

AJ Hartman Apex 8 Single Element: A single element, 8″ chord wing with great efficiency. It’s performance is similar to the GTC-300 and Kognition Designs Wing, with just a touch less initial downforce. This makes sense as it has a slightly smaller footprint. An excellent choice for this application. DATA

Kognition Designs: The CFD data on this wing is confusing. The base downforce levels seem realistic but the drag numbers seem too low and its ability to linearly increase downforce at high angles makes me think that everything above 10 degrees should be taken with a grain of salt. Efficient for this application with room to grow in the future, thumbs up. DATA

APR GTC-300: The GTC-300 is a gem of a wing. Extremely efficient and just at the beginning of its usability in this application. What that means is room for large increases in front downforce in the future. DATA

APR GT-1000: Nearly as efficient at the GTC-300 in this application, the GT-1000 might be overkill but it comes with an extreme amount of headroom. This could be the last wing you need for FWD applications, regardless of how much front downforce you make. DATA

AWD: 60% Front / 40% Rear Weight Distribution

Small Front Diffusers

Nine Lives Racing Wang: A good choice to match our small front diffusers in this application. Right in the meat of its performance capabilities, likely pretty efficient, particularly without the Gurney Flap option. Purchasing the Gurney Flap later would give additional room for performance in the future. DATA

APR GT-250: Another great option, with plenty of room for growth, particularly with the Gurney Flap option later on down the line. The headroom on this wing in this application is excellent. DATA

AJ Hartman Apex 8 Single Element: Extremely efficient in this application and with plenty of room for upgraded front downforce in the future. Great fit in this case. DATA

Large Front Diffusers-

APR GT-250: Right at the very edge of what I’d consider usable. Efficiency suffers compared to more modest wing angles. The Gurney Flap option would be mandatory and there is no margin for safety if your aerodynamic balance is too far forward. DATA

Kognition Designs: Because I don’t trust the data above 10 degrees, I would say this falls into the same category as the GT-250 in this application. We have real world usage of this wing working in a similar weight distribution range but I’d be cautious with any front aero changes. DATA

AJ Hartman Apex 8 Single Element: While this wing has less initial downforce than the Kognition wing, at higher angles, it performs better. The data is from a more trusted source as well, so I think it would be a pretty good choice for this application. There is moderate room for performance increase in the future as well. DATA

Nine Live Racing Wang-Dual Element: A good choice for this application as well. My only concern would be the small working range of adjustment this wing has. While there might be some room for future front aero improvement, the window isn’t huge. DATA

APR GTC-300: A good, safe choice wing for this application. Still efficient with room for improvements in front downforce. I like this choice in this application as it has a good cost savings vs. jumping to a multi-element wing. DATA

APR GT-1000: Nice and efficient in this application with large room for future aero improvements. This is the safest wing choice for this weight distribution in my opinion. DATA

RWD: 50% Front / 50% Rear Weight Distribution

Small Front Diffusers

APR GT-250: Safely usable in this application, but beginning to push the efficiency envelope. Headroom on performance is nearing its limit. The Gurney Flap option would be recommend. DATA

Kognition Designs: A solid choice for this application, right in the healthy range of its performance with a little room for future front aero upgrades. DATA

AJ Hartman Apex 8 Single Element: Just like the Kognition wing, but with modestly more headroom and probably more efficiency. DATA

Nine Lives Racing Wang-Dual Element: Right at the beginning of this wings performance, likely leading it to be efficient with plenty of room for more front end performance. The data says this wing is extremely efficient but from other data sources, multi-element wings usually are a tick behind in efficiency compared with a single element foil in its prime operating range. DATA

APR GTC-300: 50/50 weight cars have all the luck. Another great wing for this application. Very efficient with plenty of headroom. DATA

APR GT-1000: The GT-1000 would work efficiently in this application with an absurd amount of headroom for future performance. DATA

Large Front Diffusers

AJ Hartman Fulcrum 14 Single Element: AJ Hartman’s extra large single element wing makes its first appearance. Large, single element wings are great choices for efficiency and a large working range. I’d probably recommend the Gurney Flap option in this application. There is plenty of headroom left, but not as much as the GT-1000. DATA

AJ Hartman Apex 12 Dual Element: This wing falls into a very narrow range of use because it performs very similarly to the Fulcrum 14 Single Element but it’s less efficient and costs more. The only reason to get this wing is if you plan on going crazy with aero in the future as it has the ability to be converted into an Apex 15 Dual Element. DATA

APR GT-1000: Pretty efficient in this application, with a ton of headroom to go. A good, safe choice. DATA

Mid-Engine: 45% Front / 55% Rear Weight Distribution

Small Front Diffusers

Nine Live Racing Wang-Dual: You may have noticed a trend. The more rearward your weight balance, the larger your rear aero needs to be. If you like pushing the envelope, the Wang-Dual is right on the edge of its usability in this application. Keep in mind it’s likely not as efficient as a single element. DATA

APR GTC-300: The GTC-300 can still work in this application, barely, but the cool thing about this wing is how efficient it is at high angles. Important to note, you will have zero headroom for future upgrades if you go with this wing in this application. DATA

AJ Hartman Fulcrum 14 Single Element: Maybe just a hair too big for this application but this wing would be extremely efficient and plenty of headroom for future front end modifications. DATA

APR GT-1000: The wing is efficient, slightly down from the single elements but with an insane amount of headroom in this application. DATA

Large Front Diffusers

AJ Hartman Fulcrum 14 Single Element: Starting to push this wing pretty hard, we’d recommend the Gurney Flap option. That being said, the single element is still very efficient and there is headroom for modest front end aero improvement. DATA

AJ Hartman Apex 12 Dual Element: My thoughts on this wing remain the same from earlier. Very similar in performance to the Fulcrum 12 Single, but less efficient. Only use if the rules require you to or you plan on going crazy with front aero in the future and want to upgrade the base wing to an Apex 15. DATA

APR GT-1000: Well within the ability of this wing, efficiency starts to suffer when working the air so hard. A good choice if you think you’ll be making even more front downforce in the future. DATA

Rear Engine: 40% Front / 60% Rear Weight Distribution

Small Front Diffusers

AJ Hartman Fulcrum 14 Single Element: The most efficient choice for this application. No Gurney Flap option would be needed for it to work well. This means there’s plenty of headroom for future aero mods. DATA

AJ Hartman Apex 12 Dual Element: COPY PASTA FROM ABOVE My thoughts on this wing remain the same from earlier. Very similar in performance to the Fulcrum 12 Single, but less efficient. Only use if the rules require you to or you plan on going crazy with front aero in the future and want to upgrade the base wing to an Apex 15. DATA

APR GT-1000: Really solid choice for this application. Well within the healthy efficiency range of this wing, while still having a stupid amount of headroom to play with. DATA

Large Front Diffusers

APR GT-1000: Amazingly, we haven’t reached the limit of this wing and it shows how versatile it can be. The efficiency is really going to drop off at these levels. To make this kind of downforce in a small package, efficiency more or less has suffer. You can still make more front downforce if needed with this wing, believe it or not. DATA

AJ Hartman Apex 15 Dual Element: Holy mother of god, I want to see the car that needs this wing. It’s probably a little too big for this application but still usable. The efficiency data is a little confusing on this wing, my guess is it will be slightly better than the GT-1000. Take that with a grain of salt. There is plenty of headroom left for crazy front downforce to match this rear wing. Truly a beast! DATA

Notes:

-Convertibles need to choose a higher downforce rear wing due to poor aerodynamics hurting the airfoils performance more than a coupe. Hardtops can fix this problem.
-Have a wing you want us to add? Get us the data!
Contact us with any in-depth, vehicle specific questions!

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