Splitter Diffusers / Additional Front Grip
 

Has anyone messed with splitter diffusers yet? I modeled up and 3d printed a couple that are roughly similar to what Professional Awesome sells: https://professionalawesome.com/prod...iffusers-pair/

Attachment 151300

I printed mine in two pieces due to the limits of my Prusa.

However, now that I've pulled my splitter and have started considering where they'd fit I think it'll be hard to fit two and maybe one large one in the center is best. Another thing I've done is space the splitter down an inch below the bumper, then fill the gap with garden edging then sealed the bumper/edging to the bumper with tape. I don't want to go the full distance with a full height airdam out of HDPE yet (https://www.speedwaymotors.com/Color...0-Ft,1557.html). I've noticed one particular S2000 has added it lately, and I am guessing it works pretty well.

Ideally, a full height airdam would be used to cover the tire frontal profile, but I will be doing it by riveting a metal support with captive nuts to the bumper edge. Sheet metal attached to the bumper and splitter edge will be used to block the front profile and support the outside of the splitter, rather than using rods.

Anyway, it seems like there isn't much grassroots aero stuff floating around in S2000 world. Has anyone tried anything that has made a noticeable difference, and if so would they mind posting some pictures and going into detail a bit?

Long story short, I am heavily lacking front grip in fast corners while only running my NLR wing at 2* so I've started looking for solutions.

I'll have analysis of something similar on my site pretty soon.

To add even more front downforce, look into dive planes and wheel gurney flaps.

Excellent, I look forward to it. :)

I think the dive planes can be a phase two of what I was kind of planning. Phase one was to just block off the frontal area of the wheel, kind of like this. It looks extremely draggy to my eye, but I do not know much about aero, and I am GUESSING it is better than open wheel.

Attachment 151298
Attachment 151299

We use the PA ones on our car and while I don't have data to show they work, the car does have a lot of grip and the ever reliable butt data logger says they helped.

Another group 3D printed some of these with PLA and had some issues with them melting from the heat under the hood, so that's also something to be aware of.

if your just going for hpde stuff i did a hammerhead front splitter with end plates and it added a ton of front downforce. the rear edge of the exposed sides i used angle aluminm to act as a gurney flap and over all i went from my j's wing at ~1-2* with still a rear bias to having to bump closer to 4-5* to balance out the feel. i planned to do diffusors but didnt get around to it last season. make sure your splitter can take you jumping on it and some serious load. i talk to mike lewin of professional awesome quite a bit and the diffusors can easily double or more the frontal downforce over a flat blade design. im working on a full fiberglass 3-d splitter for next season and the classing restrains me to a max of 5" from oem body so the hammer head design is getting ditched
https://cimg3.ibsrv.net/gimg/www.s2k...89ee8804a2.jpg

one other important note is you will be introducing alot more air into your wheel wells. you need to adequately vent off the additional airflow otherwise you will be doing more harm than good. as you can see i have vented the tops of my fenders in preparation for the diffusors that should have been done last season. simply venting the top of the fender will work but ideally you would want more than just one set of small vents to do the job, something like a j's/spoon fender or something along those lines would also aide in the removal of excess pressure

For wheel well venting we did this to our car. We don't know if it's working as expected yet, we haven't done any focused testing, but I think it looks awesome, and if it looks awesome it HAS to be faster. Right?
https://cimg3.ibsrv.net/gimg/www.s2k...3dd65ce1fc.jpg

i took picks at rd.5 because i may steal the idea haha

you also have fender vents up top :p

fyi cheap fender vents on ebay, look up mustang universal hood vents. they fit pretty well and cost like $16 from china

https://www.ebay.com/itm/Universal-C...73nX:rk:1:pf:0

Steal it. I plan on doing some flow vis testing next weekend to see if it's actually doing anything, I'll share the results good or bad.

We do have boat vents on top. They're ugly, I want to try to 3D print something that looks a little nicer, in black.

just buy the ones i linked... its just so cheap to even bother making something lol. i have plans to test something else first. we'll see if it works out. if not the angle grinders coming out

Splitter diffusors are no joke. On the DDESS' car that won street class in november SLB, the addition of those tunnels added enough front downforce to shear the sheet metal splitter mounts (replaced with dev sport)

I would run the splitter without them first, and see if you have enough wing first. We found he had barely enough with the type 7 voltex at max angle, which is way more drag than a non boosted car can make use of.

I have had spats on my car for a while. There is a high speed drag advantage for sure.

I would strongly urge you do find your splitter height and drill a locator pin hole for a small self tapping screw through both halves of the devsport bracket. The slide bolts can move and the splitter finding some angle on the track will result in a lot of drag, then the splitter hitting thr ground, then no more splitter.

Thank you for the warning, I drilled some locating holes this evening. Added advantage is it is easier to pull off / put back on since you don't have to mess with lining up some sharpie marks. :) Also started doing some cardboard aided design for spats. How did you attach yours and what material did you use?
I think I have enough wing, it is a 68" 9Lives with the Emissive endplates. I have a few ideas to test at NASA Arizona Motorsports Park in a week (front will stay as-is plus spats), then I will likely have a couple of front diffusers to test for NASA Chuckwalla in February.


Thanks for the heads-up on the PLA getting melty as well, I definitely printed mine in PLA so I'll print in PETG before attaching anything. I think you are all right that the hood / fender venting is another low hanging fruit area and you're making me reconsider being completely against doing it..... it would be nice to have a car that is one color again. :rofl:

Dave linked some good videos and I really do think that a curved design that draws from the center area of the splitter and forces air into the tire area might be one of the better options we have based on common existing mount (DevSport) location. I'll draw something up this weekend because I think a large diffuser like I printed can only really be run in single configuration and in the center of the car based on places that they can fit and have an area to deposit air. I'd be curious to see where others have mounted the Professional Awesome ones.

Strong likelyhood ill be at CVR with NASA in Feb as well.

Are you running TT? If so any splitter features basically stuffs you into TT3. TT4 requires a flat splitter.

If you send me your diffuser files and rough estimate of how you're mounting them I can run them in my S2000 model, probably this weekend. Give you a rough estimate of before/after.

PLA can handle about 120 degrees in my experience. You can up that a little by heat treating them in your oven at the glass temp, or even coating them with high temp paint. Since you already have them, throw them on and give it a go.

Thank you, PM me your email address and I will send over the full version, rather than chopped up. I also plan to model an L-style diffuser in the next couple weeks.

No TT this year for me (most likely), just the UMS Time Attack that runs alongside NASA Arizona. Basically no rules other than 100TW tire and classing is Weight/HP, 10.0 - 14.99 is where I am sitting -- 90hp down or 900lb overweight based on what I have because I am unwilling to ballast for a 'fun' competition.

The Viper ACR front splitter ended up with 12 distinct diffusers; Chrysler was a little desperate to get downforce to match the large rear wing.

https://cimg1.ibsrv.net/gimg/www.s2k...ce34fce088.jpg
https://cimg0.ibsrv.net/gimg/www.s2k...66b4841f95.jpg

I need some confirmation on appropriate venting locations.

I was thinking of printing a similar large duct like Chibo has and mounting it in the center of my splitter in between some Dev-Sport brackets and having the end of the duct rise vent right in front of my radiator, see pictures below:

Some questions
-Will this create a pressure zone that reduces the effectiveness of my radiator?
-Will venting into the engine bay in front of the radiator negate the downforce effects since it will be venting into an "enclosed" location?

http://i67.tinypic.com/2lkpwmv.jpg

Don't vent it in front of the radiator, vent it behind the radiator, as far back as possible per rules. Your idea would create a huge leak path that would reduce your front downforce gains, produce a lot of drag, and suck your high pressure air underneath the car instead of through your radiator (reducing effectiveness). The goal is to accelerate the air and reintroduce it into clean flow. We want to move the air away from the high pressure zones, not into it! That is why flat underbodies are so important. With these diffusers, I would try and seal the radiator as much as possible from the splitter.

Right now I have my splitter all the way to the front jacking point. I ran a 15"x10"x3" center diffuser on the rear of my splitter CFD and got 30% more front downforce, with negligible drag penalties (simple model of course).

^Thanks! I'm going to scratch that idea then and see if I can get some much smaller ones made for the L&R sides that curve to the outer sides of the wheel wells.

Splitter 2.0 with diffusers is my spring project. I'm intending to run the newer PA curved diffusers to the wheel wells, and I'm considering adding straight diffusers to the side areas that extend beyond the sides of the bumper, to kind of function like small wings. I may experiment with additional diffusers into the engine bay, behind the radiator (hood is already vented). My current splitter already extends to mid-way along the oil pan but I may need a stronger rear support design than I currently use if I add a diffuser back there (rear is held in place with rubber wellnuts in the subframe).

I'm also considering the best way to tackle a flat floor. The exhaust is the challenge, since it hangs below everything else. The flat floor either has to be spaced down below the frame, or has to have cutouts for the exhaust. I plan to use wellnuts into the existing frame rail holes to mount whichever design I come up with.

the most important question for guys thinking about going flat floor. How do you plan to jack up the car? =)
i've been thinking about this for awhile for my other car, and I can't seem to find a good/practical solution for this.

easy. cut a slit in the flat bottom at the jacking points. thats what im gonna do.

Air jacks. Kidding... Kinda..

Yeah, I intend to leave gaps at the side jack points, or I may alternately reinforce the floor at the jack points and mark the locations under the floor. My splitter extends beyond the front jack point, but I simply heavily reinforced the splitter at that location so that I can jack the car up from the front jack point with the splitter sandwiched between the jack and jack-point. That way I can easily get the front of the car up without removing the splitter. I do have to have the front tires on ramps to reach the point, of course, even with a low-profile jack.

Found this on the internets. You'll note the two smaller outer diffusers, but the inner two are huge.

Attachment 151039

I wonder if there is an advantage to front downforce to allowing extra air under the middle of the splitter, or if that only benefits the rear diffuser at the back of the car by feeding it additional air?

^ It actually creates more front downforce. The simple goal of the splitter diffuser is to increase the velocity and mass of the airflow underneath the splitter. The more air flowing at faster speeds means an increased low pressure zone beneath the vehicle. The lower the pressure you can get beneath the splitter, the more downforce to be had.

The only reason they aren't full width is that there is an engine, radiator, suspension, and steering in the way. Purpose built cars move the steering and suspension high and move the radiators to the side. LM Prototypes and some unlimited time attack cars end up with a front wing outright.

I know the diffusers on the trailing edges of the splitter function, I'm just talking about the little kicked-up lip in the middle of the front edge. Seems like it just packs extra air the car, like the opposite of an air dam. But if it works, why not use it across the entire front span of the splitter?

I'm going to guess there is an underbody tunnel and that feeds it, I'll see if I can find more pics from that car

any one have tech write up on how air jacks work? can't find much information on it, and huge price difference between different vendors.

what car is this from?
would be interesting to see a side view to see the height different of those 2 diffusers.

i wonder what those square cut outs are for.

This came out today, there is some good info, he says the simple diffusers can double or triple front downforce.


I modeled up my splitter in case anyone wants a cheat sheet to start from. The front blade curve is not to proper shape because I was too lazy to measure multiple points, so the arc is just a three point based on the center measurement and the side measurements.

https://i.imgur.com/PnQUqHnh.png

The front blade curve is not to proper shape because I was too lazy to measure multiple points, so the arc is just a three point based on the center measurement and the side measurements.
This is what it looks like - 15/32" Birch

Main supports are DevSport mounts with a locating hole drilled. Side supports are some eyelets run up to a piece of aluminum bolted on over the front bumper supports under the headlights. Splitter sits an inch under the front bumper height, this: is used as an airdam to cover the gap between the splitter and the bumper. I seal the airdam to the bumper with a strip of duct tape, not that it really needs it. Bolts coming from the top can bolt into T-Nuts, bolts coming from the bottom should be elevator bolts. AP1 bumper fake duct cutouts are covered with aluminum sheet and some tape for now.

Attachment 149799
Attachment 149800
Attachment 149801
Attachment 149802

Improvements for the future involve maybe getting around to testing the diffusers, adding a couple supports in the rear of the splitter so I can pull it up and create some diffusing action, maybe 3d printing some angled shims for the DevSport brackets to get specific splitter angles, and definitely trying some sort of spats to cover the tire frontal profile.

So, i'm full of all sorts of good ideas on paper, and I am king of shitty execution... Got two of these printed at work. I vinyl wrapped everything for a "smoother" finish and lead into the elements. It's pretty awful execution, but hopefully the downforce is enough to overcome all of the extra drag that i've added (and net me a reduction in laptimes).

I'm going to get to test this at Chuckwalla - back to back testing - with and without splitter elements. Last time out, first week of February was a 2:03.2.
The difference will be fresh NT-01 versus 1-track day NT-01s - and the splitter elements below. I'll be going next week. I will also have ST42 brake pads on the rear versus ST43 (had a sticky caliper that wore out my left rear super fast - got a caliper on overnight order on the way...).

On to the pictures.




https://cimg4.ibsrv.net/gimg/www.s2k...336c8e1a87.jpg
https://cimg5.ibsrv.net/gimg/www.s2k...aa7c357296.jpg
https://cimg6.ibsrv.net/gimg/www.s2k...ac6825fcbd.jpg
https://cimg7.ibsrv.net/gimg/www.s2k...e6526a78b7.jpg

You might want to look at the Flo Vis thread before your tests. It would be interesting how some of the protrusions (the support and the edge of the diffuser) affect airflow.

I'm too dumb to interpret what any of that means and make any useful changes following my observations. Also, I don't want to have to deal with trying to clean all of that shit off of my control arms and other suspension components, so, no thanks.

Or, was your intended message for me to sell my S2k and buy this https://www.racingjunk.com/GT/183076...&from=search#5?

I think what he was trying to say if i understood correctly was to countersink your diffusor. The bump or little lip from the mounting face and tape is going to cause air seperation which will negatively impact the functionality of the diffusor. Your diffusors also have a pretty steep curve. Mellowing them out may also aid in keeping the airflow attached and achieving better results. Either wayits great to see the diy project

Yeah. I knew what he was saying. Anyway, counter sinking into wood takes a lot more expertise than I have. So, I just added more material to the splitter in the form of ABS sheets, to give a smoother lead in into the ducts.

I tested it out yesterday at chuckwalla, in much warmer weather, with a lot more traffic (excuses), and didn't make up any time versus my last time out. However, I definitely will note an increase in downforce up front. The back end would wash out before the front mid to corner exit at medium to higher speed turns. I dialed in a bunch of extra angle into my GTC-200 that has risers and extra large end plates - I don't think it produces enough downforce, and now i'm just making a ton of drag. I'll likely have to upgrade to a larger wing to really make the best use of this splitter. I'm looking at a GTC-250 wing. In any case, it definitely makes more downforce.

https://cimg8.ibsrv.net/gimg/www.s2k...daa07a6cb9.jpg
https://cimg3.ibsrv.net/gimg/www.s2k...38bc8c3102.jpg

Yessssssss

Sorry, I meant to reply to your PM. Hopefully our Chuckwalla schedules line up sometime here by the end of the year.

look into the 9lr wing (nine lives racing) deffinatly a decent bup in performance over the apr gtc-200 at a fraction of the cost of the gt-250

I have one, with the emissive endplates. I really like it a lot, but it definitely sticks out and is definitely 'full racecar'.

I like there mount, and they also have a chassis mount.

Thanks for the suggestion. Looks effective, although i'm not a fan of the extra extension down the back of the trunk and the extra drilling that will require - not that my trunk won't already look like swiss cheese after switching to a different wing...

@Chibo If you can PM me that cheat sheet im planning to make my own splitter also.