LotusTalk - The Lotus Cars Community - Reply to Topic
Thread: what's everyone's aero pkg look like? Reply to Thread
Title:
Message:
Trackback:
Send Trackbacks to (Separate multiple URLs with spaces) :
Post Icons
You may choose an icon for your message from the following list:
 

Register Now



In order to be able to post messages on the LotusTalk - The Lotus Cars Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










  Additional Options
Miscellaneous Options

  Topic Review (Newest First)
09-15-2016 07:27 AM
kfennell
Quote:
Originally Posted by RideMooch View Post
You can run one in Modified (DM or EM)... Don't know about XP, but I dont see any allowance in the Prepared rules. XP is weird though. Find a rear photo of the BWR XP car.
I did, that was my research into XP Easier then reading the rule book. Now back to the book to figure which of those is appropriate...
09-15-2016 07:00 AM
RideMooch
Quote:
Originally Posted by kfennell View Post
What class can I run in with a diffuser? It looks like it is even banned in XP? Sorry I just searched for diffuser and thought I was in a different section then I was.
You can run one in Modified (DM or EM)... Don't know about XP, but I dont see any allowance in the Prepared rules. XP is weird though. Find a rear photo of the BWR XP car.
09-15-2016 06:53 AM
kfennell What class can I run in with a diffuser? It looks like it is even banned in XP? Sorry I just searched for diffuser and thought I was in a different section then I was.
09-15-2016 05:40 AM
RideMooch
Quote:
Originally Posted by kfennell View Post
My reading shows a 25" diffuser with strakes a minimum of 6" apart is allowed, my diffuser meets these rules (difflow railer I think), can anyone show me I am wrong?
It does look like the GRP wing above would NOT be AX legal in any class?
Where are you getting that diffuser rule? SSM rules do not allow diffuser change from OE.
copied and pasted SM rules on aero below. If doesn't say you CAN do it, you can't.

Quote:
Originally Posted by SCCA SM rules
K. Aerodynamic Aids: Wings may be added, removed, or modified. Non-OE
wings may only be attached to the rear deck/hatch area behind the center-
line of the rear axle. The total combined surface area of all wings shall not
exceed 8 sq. ft. (0.7432 m2) as calculated per the Wing Area Computation
in Section 12. The number of wing elements is limited to 2.
Wings, and any component thereof, may not extend beyond the vehicle
width, as defined by the outermost portion of the vehicle doors, less mir-
rors, door handles, rub strips, and trim. In addition, no portion of the wing
or its components may be more than 6.0” forward of the rear axle, more
than 0.0” beyond the rear most portion of the bodywork, or more than 6.0”
above the roofline of the vehicle, regardless of body style. For convertibles
and roadsters, the highest portion of the windshield frame will be consid
ered the highest portion of the roof; however, a convertible or roadster uti
lizing a hardtop will use the highest portion of the hardtop as the roofline.
Reinforcements to the wing mounting area may be used, but may serve no
other purpose. Body panels to which a wing mounts must remain func
tional (e.g., trunk lids and rear hatches must open). Wing endplate surface
area is limited to 200 sq. in. (1290.3 cm2) each and limited to a maximum
of 2.
Except for standard parts, wings designed to be adjustable while the car is
in motion must be locked in a single position.
Canards are allowed and may extend a maximum of 6.0” (152.4 mm) for
ward of front bodywork as viewed from above. No portion of the canard
may extend past the widest part of the front bodywork/fascia as viewed
from above. Canard area will be measured in the same manner as wings
using Section 12. Canard area may not exceed 15% of total wing
allowance. The sum of canard area and rear wing area may not exceed the total
wing allowance.
L. Front splitters are allowed and shall be installed parallel to the ground
(within ±3° fore to aft) and may extend a maximum of 6.0” (152.4 mm)
from the front bodywork as viewed from above. Splitters may not extend
rearward past the centerline of the front wheels. No portion of the splitter
may extend beyond the widest part of the front
bodywork as viewed from above.
Aerodynamically functional vertical members, such as splitter fences
or endplates, are not allowed.
09-14-2016 11:16 AM
XHILR8N! Attachment 1010786
09-14-2016 10:49 AM
glagola1 For SSM, there is no allowance for replacing or adding a diffuser. That means you can't touch oe... not even to fill the hole.

I'm not versed on the XP rule set.
09-14-2016 09:08 AM
kfennell
Quote:
Originally Posted by kfennell View Post
Diffusers are banned in SSM? Did not know that, I guess XP for me then? I don't even have the OEM anymore.
My reading shows a 25" diffuser with strakes a minimum of 6" apart is allowed, my diffuser meets these rules (difflow railer I think), can anyone show me I am wrong?
It does look like the GRP wing above would NOT be AX legal in any class?
09-14-2016 08:48 AM
cyow5
Quote:
Originally Posted by acslater View Post
Very cool, I get where you're coming from now. My next project is going to be to extend the fences on the diffuser too - crazy that it yielded such an awesome improvement in that piece, even with the center section stalled out!
Yeah, I am looking at using something consumable like a heavy rubber or polycabonate since they'll scrape on everything. Another option I am looking at is hinging it at the front of the extension so it can deflect upwards. That's the trickest, but the others are easier.
09-14-2016 08:42 AM
kfennell
Quote:
Originally Posted by RideMooch View Post
I'd love to fab a splitter for my car, but then I can't get in my driveway and I still street drive it a lot. And unfortunately in SSM an aftermarket diffuser is verboten.
Diffusers are banned in SSM? Did not know that, I guess XP for me then? I don't even have the OEM anymore.
09-14-2016 08:40 AM
acslater
Quote:
Originally Posted by cyow5 View Post
Right, the diffuser in this case was heavily underutilized. Aero is all about package and not components, so you just have to try and see (or run a proper sim on a supercomputer). Catching something like ride height, wing type (OE exige style in their case), etc, and you can achieve weird results. I am building my entire package around the diffuser, so that's why it is important to me. Look at the downforce of the wingless 458 and you'll see the virtues of underbody aero. I am also adding vertical extensions to my side skirts (just got the UPS notification they arrived!), extensions to the diffuser strakes, and cut inlets in the front splitter (recall that splitters consequently reduce underbody airflow). I also am going to add oil cooler block-offs and a contoured underbody which is will work great with the vertical skirt extensions.
Very cool, I get where you're coming from now. My next project is going to be to extend the fences on the diffuser too - crazy that it yielded such an awesome improvement in that piece, even with the center section stalled out!
09-14-2016 08:38 AM
cyow5
Quote:
Originally Posted by acslater View Post
@cyow5 , seems to me this paper makes an argument for a higher-mounted wing, up to a certain point. But higher was MORE efficient than lower-mounted wings. The caveat to that was that the exhaust was running THROUGH the diffuser and stalling it out, meaning that there wasn't interaction between the wing and diffuser. That's not the same as saying that a low-mounted wing with an effective diffuser is more efficient than a high-mounted wing with an effective diffuser.
Right, the diffuser in this case was heavily underutilized. Aero is all about package and not components, so you just have to try and see (or run a proper sim on a supercomputer). Catching something like ride height, wing type (OE exige style in their case), etc, and you can achieve weird results. I am building my entire package around the diffuser, so that's why it is important to me. Look at the downforce of the wingless 458 and you'll see the virtues of underbody aero. I am also adding vertical extensions to my side skirts (just got the UPS notification they arrived!), extensions to the diffuser strakes, and cut inlets in the front splitter (recall that splitters consequently reduce underbody airflow). I also am going to add oil cooler block-offs and a contoured underbody which is will work great with the vertical skirt extensions.
09-14-2016 08:33 AM
acslater FWIW, ReVerie generally says that as high and far back as possible (under given rules) is the rule of thumb for mounting a wing, and that compound wings are only effective if their twist has been designed specifically to suit the airflow over the vehicle it's being installed on.
09-14-2016 08:30 AM
acslater @cyow5 , seems to me this paper makes an argument for a higher-mounted wing, up to a certain point. But higher was MORE efficient than lower-mounted wings. The caveat to that was that the exhaust was running THROUGH the diffuser and stalling it out, meaning that there wasn't interaction between the wing and diffuser. That's not the same as saying that a low-mounted wing with an effective diffuser is more efficient than a high-mounted wing with an effective diffuser.
09-14-2016 08:23 AM
RideMooch
Quote:
Originally Posted by acslater View Post
As far as diffuser, you should be able to at least run an above-exit exhaust and close the exhaust hole, right? From what I understand, the oem exhaust tips coming through the diffuser have been shown to render it effectively useless. (You may have already done this, can't tell from your picture)
Haven't done that yet, but it's high on the list (PPE header, catless test pipe, BOE QS); however, I seem to recall the way the rules are written you still cant close off the OEM hole in the diffuser. Maybe glagola knows the answer to that.
09-14-2016 08:20 AM
acslater
Quote:
Originally Posted by RideMooch View Post
I'd love to fab a splitter for my car, but then I can't get in my driveway and I still street drive it a lot. And unfortunately in SSM an aftermarket diffuser is verboten.
As far as diffuser, you should be able to at least run an above-exit exhaust and close the exhaust hole, right? From what I understand, the oem exhaust tips coming through the diffuser have been shown to render it effectively useless. (You may have already done this, can't tell from your picture)
09-14-2016 08:19 AM
cyow5
Quote:
Originally Posted by RideMooch View Post
You mean this ORE wing? can't tell how it's mounted but looks like its just on the trunk lid which doesnt seem very secure or effective. Also doesn't look like they're marketing this, but it's a one off.
Right, it is just a one-off but still my favorite I've seen. I spoke with the owner of that car and it seems well-done. Also, think about the static physics and you'll find that you do not need to mount directly to the chassis as long as whatever you mount to can support it.

I always prefer efficient results over brute force, so I lean towards low/rear mounted wings. Clean air is great for a constant cross section wing, but remember our cars have underbody aero. Mounting low and rear pulls more air through the diffuser. The wing works less effectively since it does not have clean air, but you can get the same downforce with less drag. Again, see this paper for some really neat (and often counter-intuitive) insights

http://www.abendanio.com/Manuals/Aut...rodynamics.pdf

His book also goes into a little more detail on the results. Another interesting point, the Exige is not a true fastback design since it has the wire mesh back there, so the aero isn't nearly as clean as, say, Phil's true fastback.

09-14-2016 08:17 AM
RideMooch
Quote:
Originally Posted by lotus90 View Post
I recommend front air splitter. it helps with down force and protects front clam. I run front air splitter and difflow diffuser. I find the car feels more planted.
I'd love to fab a splitter for my car, but then I can't get in my driveway and I still street drive it a lot. And unfortunately in SSM an aftermarket diffuser is verboten.
09-14-2016 08:11 AM
lotus90 I recommend front air splitter. it helps with down force and protects front clam. I run front air splitter and difflow diffuser. I find the car feels more planted.
09-14-2016 07:50 AM
acslater +1 for Phil's swan neck design. I'm running Reverie aero all around with their tallest stanchions, but I plan to eventually go frame-mounted.



So far, no issues with the wing overpowering the mounts or putting any cracks in the clam even at 135 mph

By the way, one comment about wings, and specifically the APR GTC200 (which really is a great deal): if you mount it high enough that it's in clean air, the compound design diminishes the effectiveness since the wing will have different stall speeds along its length.
09-14-2016 07:30 AM
glagola1
This thread has more than 20 replies. Click here to review the whole thread.

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

 
For the best viewing experience please update your browser to Google Chrome