Discussion in 'Cars' started by AYOUSTIN, May 31, 2017.
IF this guy is street legal...so can you be!
Lol I've debated zip tying an airhorn to the cage facing out the window before
Honestly this car is not that wild compared to some of the stuff that is street legal in this state.
"Street legal." All good when you have an uncle's, neighbor's, cousin that can write off on inspections.
Also PM me addresses if you want some CDR love.
Does that include me?
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No really it's like lights windows belts and horn for a safety inspection here emissions are separate but you can get a tag and drive around paying the fine. I drove my last car 18 months on a failed emissions. Every three months you go fail and pay your $14 and they send you on your way
Got the new splitter almost all designed. I just need to confirm some dimensions and make some small tweaks. Decided to make this one a project for school since we've got a cnc router that can cut 4x8' sheets so I'll be making it out of a 4x8' sheet of hdpe. The aluminum air dam is just a sheet that can be bought from McMaster (actually everything in the model except the hdpe can be bought on McMaster) and it's riveted to L brackets that are riveted to the splitter. The vertical elements on the end are bent sheetmetal and are bolted to the splitter with nutserts on the bottom so there's no nuts to fall off. After I get it made I'm probably going to line the air dam with some rubber trimming so there's no sharp edges. I'm pretty excited to get this made as my current splitter is pretty trashed.
Lol @ $14. Such a serious punishment.
Are you concerned about sag? Considered rounding the sharp bends (as it starts going to the rear) to remove the stress concentration?
No, it'll be mounted the same way as my current one. 6 mounts total, 2 connect the outside edges of the curved section to the frame rails, two cables hold it up on the eyelets in the front and connect to the crash bar and two brackets mounts the rear of it to the subframe.
All the sheetmetal has radii at the bends. I may throw a radius on the splitter edges but I'm not concerned about it being stressed. The material is stronger and has more flexibility than the alumalite my current one is made of.
How far from the ground will this end up?
Since this car is not really for the street I would consider making it lower and stick out further.
If you are concerned about being too low you could put on replaceable skid blocks
The current one is about 4" off the ground, maybe a hair more. This should be just as low. If I wanted to make it lower all I have to do is make new frame rail brackets which is just bent up aluminum strips and make the cables a bit longer so it wouldn't be hard. I did consider adding a few more holes to rivet some aluminum sheet to the bottom of it on the sides because it does scrape a lot there.
The current splitter sticks out about 3" and tapers into the countour with the bumper at the edges so it doesn't stick out at all on the sides. The new one sticks out 5" all the way around the air damn so there's a good amount more horizontal area for the stagnation pressure to work upon and there's the vertical elements on the ends that should also help. My reason for 5" is I don't know how much of a difference this is going to make over my current splitter but I think it should be decent. I'm honestly just guessing at most of this, my knowledge of aero is pretty much me reading on the internet and listening to podcasts of guys who design aero. I did design the splitter to be pretty modular so if I decide that 5" isn't enough all it takes is a few keystrokes to make a new one that extends further.
Next year I'm hoping to start competing in global time attack and the rules on aero is pretty open for the class I'll be in (limited class). The only big stipulations that I have to keep in mind for limited class is:
- No flat underbodies
- Splitters and diffusers can only go to the axle centerlines
- Barge boards can only go 12" in from the pinch welds
- Exhaust must exist past the front axle (minus wastegate dumps)
- Dog boxes are allowed
- Tires must be 80 treadwear or higher
- They don't state whether aftermarket subframes are allowed or not. They aren't in the class before limited, but they are in the class after limited
- The chassis is free reign forward of the front strut towers and rearward of the rear strut towers, so tubing it is allowed.
Front aero matters much more than rear aero on evos because they tend to plow at higher speeds and gaining rear downforce is pretty easy compared to front downforce. After this season I'll probably start looking into getting canards, making a diffuser and barge boards. I doubt I'll have the money for dog gears and frankly I don't think I want a dog box as they're an absolute cunt to drive on the street. And fortunately/unfortunately the treadwear rating has been bumped down from 100 to 80 this year which is nice because most guys were still running 200 treadwear RE-71s because they're stickier than every 100 treadwear tire but still kinda sucks because the only 80 treadwear tire out there is Hankook TDs which are good tires but not exactly easy to purchase and don't offer a ton of sizes.
Lower is better, anything you can do to reduce the amount of air under the car will help with front down force.
Ideally it would be zero but obviously you are limited by track topography and suspension travel. For competition I would make the splitter out of something like plywood that is cheap and easily replaced so that you can be too low and scrape but just slap on a new one when needed.
I do remember reading that from an article. Something I couldn't find much on was AOA for splitters. Do you have any recommendations?
The hdpe that I'm making it out of is just a 4x8' sheet that can be bought at menards for $30 and I think it'll be stronger and have more give to it than plywood. I'm debating cutting out two or three to have backups so I don't have to find someone with a router large enough to make more after I leave school.
I have no real answer but my understanding of splitters is that they don't work like wings where you need an angle to generate down force. They generate down force by exploiting the natural high pressure area at the front of the car to push down on the splitter and to keep the high pressure air from spilling under the car and generating lift.
The real answer I think is related to suspension, you need to have enough of an angle so that you minimize the likelyhood of getting the bottom exposed and picking the car up. Yours is too small to flip the car but could send you off course if you say hit the curbs at the top of a crest.
I don't know if they come near you but the thing that started getting me to understand basic aerodynamics was going to a then American lemans series race, the pits are wide open and very laidback. You can get very close to the cars and look at how they are approaching aero.
I was actually leaning on a stack of corvette tires while watching them work on the car. That's how laid back it was.
Got my Hardrace spherical LCA bushings in the mail today. Quality seems pretty good considering how cheap they are compared to the rest of the spherical options. The stiction on them seems decentish, they definitely required a bit of persuasion to move the first time but after that they freed up a bit and move fairly easily now. I plan to pack in some CV grease on the bearings when I put the control arms back in the car to hopefully keep dirt away from the bearing and extended the life of them a bit.
I recently got some spherical bearings like that for the mustang, same thing as far as the bearing being so tight it could barely move. It will break in and be fine.
Get some rubber seals to keep the grease inside those bearings and further protect them from the elements and road debris.
Which bearings did you get for your mustang? I've been looking into it for Monday, but haven't made a choice yet.
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Steeda upper diff bearing.
We have an s197 so solid axle fail/win. The bearing along with J&M control arms are going on next month to hopefully loosen up the rear a bit more. All mustang suspension parts are trash except for a select few, so it was a tough decision for us too.
Don't you have the s550 with IRS?
Yes I've got the S550. I've been looking into the vertical link and lock outs for the rear irs.
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