ITS Downforce Figures?

[VtecBuddy]

Acura must have some of their own data on this. Whether they've actually discussed it publicly or not, who knows.

I'm sure they do, I feel like if the car made substantial downforce, they'd mention it somewhere. Maybe Savagegeese or Jonathon Rivers would be good people to ask about this?

 

[Snugs24]

Ground effects are hard to accomplish, cars need to be quite low for ground effects to be substantial. The Ford GT accomplishes it because it can dynamically alter ride height for the track and get really low. But I can't imagine the ground effects are that substantial on more common production cars compared to the downforce you can accomplish with a big wing or air dam. You also need to make sure the underbody of the car is really smooth which takes a lot of additional panels.

Yeah aero is all about smooth body surfacing to feed the rear.

I'm sure they do, I feel like if the car made substantial downforce, they'd mention it somewhere. Maybe Savagegeese or Jonathon Rivers would be good people to ask about this?

I’m telling you man, it’s American skunkworks lol. Americans don’t talk about ground effects. The diffuser on both generations ford GT’s was an after thought the prototypes had no diffuser then the production versions had massive diffusers.

Having a splitter/diffuser is much more “understated” then running a wing, or so the public would like to have you think.

Europeans and their Valkyries, Sennas, Huayra BC’s, and formula 1’s put it in your face. Americans just don’t talk about diffusers, I’ve noticed that.

Wouldn’t surprise me if the new mustang GTD ended up with a massive diffuser, and became a phenom like the GT’s that preceded it.

No one talks crazy aero here, and I think it’s because we care more about aviation.

I can’t for the life of me find downforce figures for the 2005 GT and it has a smooth underbody feeding it’s massive diffuser at the back.

 

[VtecBuddy]

I do see a 3d model of the ITS online for 150 bucks or so, I guess if someone really wanted to they could try running it through an ANSYS flow simulation haha

 

[creaturemachine]

Also something to note about the rear diffuser. On the Type S it doesn't cover underneath the exhaust or extend as far as it does on the FL5:

Yeah that is not a functional floor or diffuser. It's doing just what it's doing for every other Honda Civic on the road, increasing fuel efficiency.

 

[SolarTrans]

Yeah that is not a functional floor or diffuser. It's doing just what it's doing for every other Honda Civic on the road, increasing fuel efficiency.

Acura says the rear diffuser reduces lift on the ITS. Absent independent testing, I do take their word that it’s functional

 

[optronix]

Acura says the rear diffuser reduces lift on the ITS. Absent independent testing, I do take their word that it’s functional

I tend to agree though... if it's not actively introducing lift then technically it's "functional"... but let's be real we all should recognize it's not a racecar.

I think with this, it's just a "take the win" situation. It's a great car, personally I don't think you really need to try to peel it back all that much.

 

[34631-fk8]

I do see a 3d model of the ITS online for 150 bucks or so, I guess if someone really wanted to they could try running it through an ANSYS flow simulation haha

May I ask where you found this?

 

[creaturemachine]

Here you go guys, a functional diffuser on your average car adds a hefty nine whole pounds of downforce.

https://www.verus-engineering.com/b...-necessary-for-a-rear-diffuser-to-function-76

This is with more of an actual diffuser fitted and not a lumpy bumper cover. So go get your groceries if you want some downforce.

 

[nix6speed]

Here you go guys, a functional diffuser on your average car adds a hefty nine whole pounds of downforce.

Every little bit counts!

 

[SolarTrans]

Every little bit counts!

Better than adding 9lbs of lift!

Also, those figures depend heavily on speed; the faster you go the bigger difference a functional diffuser will make vs a standard rear end

 

[RamVA]

Ground effects are hard to accomplish, cars need to be quite low for ground effects to be substantial. The Ford GT accomplishes it because it can dynamically alter ride height for the track and get really low. But I can't imagine the ground effects are that substantial on more common production cars compared to the downforce you can accomplish with a big wing or air dam. You also need to make sure the underbody of the car is really smooth which takes a lot of additional panels.

Agreed. The car is not nearly low enough, and the underside not smooth enough for any ground effects to be meaningful.

 

[Gansan]

Here you go guys, a functional diffuser on your average car adds a hefty nine whole pounds of downforce.

https://www.verus-engineering.com/b...-necessary-for-a-rear-diffuser-to-function-76

This is with more of an actual diffuser fitted and not a lumpy bumper cover. So go get your groceries if you want some downforce.

Let's at least quote the sentence where the nine pound number comes from:

The downforce increase from adding a diffuser to a dirty floor model was 9 lbs on the overall vehicle, while the downforce on the diffuser itself was 61 lbs.

It seems unlikely Honda engineers would say in interviews they spent a lot of time on the rear diffuser if it was just a bumper cover. The article you linked to was all about how a dirty floor car benefitted from the diffuser MORE than the clean floor. That means we can't completely dismiss it as non-functional because the floor isn't like a McLaren. Looking it up...Honda quotes 63N gain @ 200km/h from the diffuser which isn't a lot but it's still 14 lbs. The car is a road car and not sitting 2 inches off the ground which would be more ideal for ground effects.

Remember also that the aerodynamicists have tweaked the rest of the car the best they can to take advantage of the diffuser they have. They are in the room when the car's being designed and they have the power to do their own tweaks. They aren't tacking on an aftermarket generic one from Rock Auto.

 

[VtecBuddy]

May I ask where you found this?

Here you go: https://www.cgtrader.com/3d-models/car/car/acura-integra-type-s-2024

 

[kjechel]

Here you go guys, a functional diffuser on your average car adds a hefty nine whole pounds of downforce.

https://www.verus-engineering.com/b...-necessary-for-a-rear-diffuser-to-function-76

This is with more of an actual diffuser fitted and not a lumpy bumper cover. So go get your groceries if you want some downforce.

I think you missed some important points by just reading the conclusions and not looking at the data in the table. Comparing the top two rows (Dirty Floor Only vs. Dirty Floor + Diffuser), note that drag was decreased by over 9% (259.5/285.7). I think that's the most important benefit. Lift was reduced by just over 7%, but since they didn't give the loads on the front & rear axles we don't know how the lift reduction was distributed (front to rear). Although one could assume it's mostly at the rear, the underside views show the diffuser affects the pressure distribution far ahead of the rear axle. Of course these conclusions are for a generic model, so the ITS may behave somewhat differently.

Tape some tufts (see https://www.amateuraerodynamics.com/2022/02/tuft-testing-how-to-manual.html) on your diffuser and have someone following take video to see if the flow is attached.

 

[kjechel]

Here you go: https://www.cgtrader.com/3d-models/car/car/acura-integra-type-s-2024

It's got a sunroof!