Jump to content

Spoilers vs diffuser vs wing


wvumtnbkr
 Share

Recommended Posts

Can anybody help with my mental waffling?

 

What should be on the back of our racecars?

 

Spoiler:

Pros - Easy to make - easy to adjust - works okay

Cons - draggy - not efficient

 

Diffuser:

Pros - works well - not a huge drag penalty

Cons - difficult to make correctly - may be difficult to determine max efficiency

 

Wing:

Pros - works well - not a huge drag penalty

Cons - difficult to make correctly - may be difficult to determine max efficiency.

 

 

What say the hive?  How would you "dip your toes" into the aero world?

 

We have an airdam on the front of our car (mostly for proper cooling of the engine).  I was thinking that a spoiler is easy to make and may compliment the airdam.  At the same time, is it worth some sideskirts and chopping up the rear bumper?

 

Do you think we would even notice a difference?

 

Is going the "full monte" with airdam, splitter, flat underbody, diffuser, and wing worth it?  Can you get 85% of the way to these results with airdam, spoiler, sideskirts, and rear bumper massaging?

 

 

Car is question is the amazing 1987 Mazda Rx7.

 

 

racecar wgi cropped.jpg

Link to comment
Share on other sites

Do you feel like you need more rear downforce? A long rear spoiler laid down at about 10* will actually cut drag, but not add a lot of downforce (think pro-mod drag cars). I think you'd see a net drag reduction and an overall increase in downforce if you blocked those tires off...

  • Like 1
Link to comment
Share on other sites

Looking forward to the responses.  I'm coming to the conclusion that my previous assumptions on aero devices/modifications in this series were wrong (I'm man enough to admit it). For 20pts, a splitter/wing combo might be the best points spent towards reducing lap times.

 

Link to comment
Share on other sites

We are noticeably faster through the corners with our big fatty wing, air dam and splitter than any other miata,, and most any other car in the west

 

Just added side skirts but didnt do data to really know for sure since we drove on RS4's for the first time as well.  Love the RS4's btw.

 

We are planning on Diffuser next and maybe one day a flat floor.  But with that comes thermal challenges.  @Hi_Im_Will is the resident expert of going "full retard" on aero and its benefits/difficulties

 

 

Link to comment
Share on other sites

I always like a rear end message...  wait never mind.  

 

Id go the route of wing and add splitter to the air dam.    A diffuser is cool , but not sure it does much without going the full flat bottom route.   Flat bottom is effective but creates some heat problems and is a maintenance pain in the butt.  (Have extra stuff to take a part to work on anything 

 

Just sneak it into Will's shop it'll get aero' up before he even notices it's not his car. ;)

 

Edited by JDChristianson
Link to comment
Share on other sites

Just now, Bremsen said:

Looking forward to the responses.  I'm coming to the conclusion that my previous assumptions on aero devices/modifications in this series were wrong (I'm man enough to admit it). For 20pts, a splitter/wing combo might be the best points spent towards reducing lap times.

 

Do aero right and you have more speed for no more fuel, vs adding power.  Aero should also make the car more driveable vs more power can make the car a handful

  • Like 1
Link to comment
Share on other sites

  • Technical Advisory Committee

if you add rear downforce, you are going to have to add front downforce.

 

At RA this year, our wing was so good that we had to put it at a negative angle to keep it from overpowering our splitter.

 

Now we have 6 more inches of splitter, and the wing is STILL at a neutral AOA. 

 

I seriously miscalculated the efficiency of the airfoil I selected.    

 

 

Dont do any diffuser work if you dont also do a full undertray.  

 

Easy button is +splitter+wing

 

As with everything though, the car is a system and making changes in one place will cause you pain in another - you just woln't know where until it shows up at a bad time....

 

 

  • Like 2
Link to comment
Share on other sites

2 minutes ago, red0 said:

Since chumpcar has no aero limits,  why are people running such small wings?

 

Shouldn't the setups look more like this:

 

maxresdefault.jpg

Someone should so that we can get a bit of a limit in the rules.  ?

 

I think there should at least be a rule limiting width to no wider than the car and maybe limit to single element and how high a wing can be.  

  • Like 1
Link to comment
Share on other sites

39 minutes ago, ross2004 said:

Do you feel like you need more rear downforce? A long rear spoiler laid down at about 10* will actually cut drag, but not add a lot of downforce (think pro-mod drag cars). I think you'd see a net drag reduction and an overall increase in downforce if you blocked those tires off...

What do you mean by block those tires off?

 

They don't actually stick out from the car (....much).  They are pretty flush.

Link to comment
Share on other sites

  • Technical Advisory Committee
16 minutes ago, red0 said:

Since chumpcar has no aero limits,  why are people running such small wings?

 

Shouldn't the setups look more like this:

 

maxresdefault.jpg

 

Why?  because this is W2W racing and not Time Attack

 

If I thought I could run that splitter and have it last 24 hours without getting run over, I woulda built it.

  • Like 1
Link to comment
Share on other sites

  • Technical Advisory Committee
20 minutes ago, Huggy said:

 

Why?  because this is W2W racing and not Time Attack

 

If I thought I could run that splitter and have it last 24 hours without getting run over, I woulda built it.

 

In the past we have gone multiple years with 0 contact, its not like it happens often. 

Link to comment
Share on other sites

We changed everything all at once without quantifying a single thing independently. The car is fantastic in the corners but we have a gigantic drag penalty. Not sure whether it was the tires or the aero but this thing is crazy fast through a high speed corner now and small adjustments to the wing have a dramatic effect on balance and under/oversteer tendencies, so we our guesswork wasn't awful. Probably the best 20 points you can spend but it is a lot of work.20170922_165021.thumb.jpg.9e7091a7dc6aed8fd9e690bea4969ea8.jpg

 

  • Like 2
Link to comment
Share on other sites

1 hour ago, ross2004 said:

Must be an optical illusion, the front and rear's look like they're hitting a decent amount of air.

Well, how much is too much?  An inch?  Half an inch?  I can roll the fenders and pull them out if it's worth it!

Link to comment
Share on other sites

  • Technical Advisory Committee

Another 240sx showed up at VIR with wing and spliter ,we use to run very close times .. I caught them during my stint and we ran together for many laps they definitely had an advantage in the corners but I would walk back by them and pull a few car lengths on the front straight ..  Finally schooled him in traffic and walked away ..  Talking with them after the race they asked how we had added power and I said we had not changed a thing and were running 4 year old tires ..  the next race I saw them all the aero was gone . When you don't have enough horsepower to begin with the drag penalty is to much to overcome .... just another thing to consider ...

  • Like 2
Link to comment
Share on other sites

Spoiler at less than 30 degrees or so reduces drag, air dam reduces drag, splitter and wings increase drag while adding down force, haven't read up on diffusers yet. I don't think I'm smart enough anyway.  I opted to reduce drag as we don't get passed much in the corners. BTW what do you all think of a maximum tire section width of 205mm?

Link to comment
Share on other sites

55 minutes ago, Eman911 said:

BTW what do you all think of a maximum tire section width of 205mm?

 

I think it penalizes the heavy cars which are typically running a V8 which already are in the penalty box on fuel consumption.  Might as well just write Class D cars out of the series.  How about making a rule for 2.5 gallons of fuel capacity allowed per engine cylinder because that is what I would like to have?:lol:

Edited by Ron_e
  • Like 2
Link to comment
Share on other sites

2 hours ago, Eman911 said:

Spec 155/80r13s!

 

36 minutes ago, mender said:

By all means, go right ahead and run them; I'll stick with 255s. :P

 

Agree.  I think from now on people should have to run their recommendation for 20 races as long as they fit within the current ruleset to prove/disprove their particular theory and how much fun it will be.  @Eman911 for the win.  Once they work off their banishment they are allowed to make another stupid recommendation.:D

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...