inh

Does anyone know of some proven ways to improve the aerodynamics of an 88-91 CRX? I remember reading that the Mugen kit was supposedly wind tunnel tested to improve the aero, but does anyone know of anything else?

Also, does anyone happen to know the frontal area of a CRX? I know the coefficient of drag is .3

What I've learned so far...

88-91 CRX and CRX Si Coefficient of Drag is 0.30
88-91 CRX HF is .29

I estimate the frontal area of a CRX to be:
19.46 feet^2

based on 85% of width (1675mm) x height (1270mm).

Please check that though, because I am horrible at math


From an article about the Honda Insight:
http://www.hondanews.com/categ...s/246
"At highway speeds, the airflow around a vehicle becomes turbulent. Turbulent air generates considerably more drag than smooth-flowing (laminar) air. In addition, as speed increases, the power required to overcome turbulence-induced drag rises exponentially. To combat the effects of drag, Honda engineers designed the Insight's body to be highly aerodynamic. Its 0.25 coefficient of drag (Cd) is one of the lowest of any mass-produced automobile in the world. In comparison, the Honda Civic Hatchback, with roughly the same 1.9 square-meter frontal area as the Insight, has a Cd of 0.36, and needs around 32 percent more power to operate at the same speed as the Insight."

and

"At the very back of the Insight, the teardrop shape is abruptly cut off in what is called a Kamm back (a distinctive design feature also shared by the Honda CRX). The Kamm back takes advantage of the fact that beyond a certain point there is little aerodynamic advantage to be gained by rounding off or tapering and extending the tail section of an automobile, so one might as well abruptly truncate it at that point. The Kamm back is a design feature that has been incorporated into many high-performance automobiles and racing cars over the years."

About the Kamm back:

"Kamm Back
Named for the German aerodynamicist W. Kamm, who discovered that drag begins to increase after the rear of a car's cross-sectional area is reduced to 50 percent of the car's maximum cross section. "

Big thread on aero:
https://honda-tech.com/zerothread?id=812942

Info on some NSX aero:
http://asia.vtec.net/beystock/....html

Modified by inh at 4:34 PM 9/25/2007


Modified by inh at 4:39 PM 9/25/2007


Modified by inh at 4:43 PM 9/25/2007


Modified by inh at 5:13 PM 9/25/2007

CRX Toad

You could tape up all the cracks between bumper, lights and hood. Remove windshield wipers.

What are you trying to accomplish?

inh

I would like to avoid using tape and the like, im looking for a more permanent solution.

The end goal is to see how fast she'll go on the salt flats.

So far, I know that the rear bumper is one hell of a parachute, so I plan on replacing it or making a cover for the underside so it wont trap air, and i've read that building a cover for the wipers would help, though I'm sure removing them would be best.

Would routing air from those vents on either side of the radiator opening in the bumper help? Like, routing it using hoses to help cool the brakes, and then providing a way for the air to exit out the rear of the fender?

CRX Toad

Well don't need brakes at the salt flats so I wouldn't do that your just creating more drag.

If it is a salt flat car you could do one piece front end. If you want it to be street legal you will have to get creative at best.

What class are you shooting for?

inh

Not shooting for any class or anything. I want to see how fast she'll go, and I damn sure dont want to attempt it on the streets, ya know?

I know (think?) the CRX already has some decent aerodynamics, I'm just wondering what can be done to help em out a bit, but still stay street legal.

inh

Any suggestions guys? I'm trying to keep it clean looking and street legal..

How about some aero resources?

Crx dude

for the salt flats you really cant keep it street legal. how fast do you plan on going? you have to go really fast for aerodynamics to really make differance. One thing you can do is put holes in the back bumper to allow air to pass through and a one piece front end. just my .02 cents

Ass$nyper

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Crx dude &raquo;</TD></TR><TR><TD CLASS="quote">for the salt flats you really cant keep it street legal. how fast do you plan on going? you have to go really fast for aerodynamics to really make differance. One thing you can do is put holes in the back bumper to allow air to pass through and a one piece front end. just my .02 cents</TD></TR></TABLE> Areo starts playing a factor at about 60 and gets more important the faster you go.

Easiest and cheapest will be a areo tuned front lip.

Adding some down force on the front will be your first step.

I know a few guys have done high speed runs in these cars so give a search a try.

inh

i want to see how close to 200mph i can get...

Ass$nyper

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by inh &raquo;</TD></TR><TR><TD CLASS="quote">i want to see how close to 200mph i can get... </TD></TR></TABLE> 20 year old... aiming for 200 in a crx... I'm already doubting this thread.

eh worse to worse I posted what I can.

inh

...about to return from iraq with lots of cash i want to spend on my car...

500-600 whp B20 is enough to get close, I just want to do all I can

Ass$nyper

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by inh &raquo;</TD></TR><TR><TD CLASS="quote">...about to return from iraq with lots of cash i want to spend on my car...

500-600 whp B20 is enough to get close, I just want to do all I can</TD></TR></TABLE> You'll need alot more cash then you think, trust me.

Friend of mine is over 30k for 200 in an F-body camaro. A car that stock does 182 on the flats.

Either way, best of luck.

Crx dude

nobody mentioned that he's gonna need a big dirty triple deck spoiler j/k

Ass$nyper

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Crx dude &raquo;</TD></TR><TR><TD CLASS="quote">nobody mentioned that he's gonna need a big dirty triple deck spoiler j/k</TD></TR></TABLE> A spoiler will help, I remember a drag guy, with alot of power gaining 3 mph from an areo tested wing.

Crx dude

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ***$nyper &raquo;</TD></TR><TR><TD CLASS="quote"> A spoiler will help, I remember a drag guy, with alot of power gaining 3 mph from an areo tested wing.</TD></TR></TABLE>
denitatly would but it would have to be the right spoiler and not a jc whitney special.

inh

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ***$nyper &raquo;</TD></TR><TR><TD CLASS="quote"> You'll need alot more cash then you think, trust me.

Friend of mine is over 30k for 200 in an F-body camaro. A car that stock does 182 on the flats.

Either way, best of luck.</TD></TR></TABLE>

Im not going for 200mph as my end all goal. I'm just seeing what things I can do to help it along and see how close I can get.

I was also hoping to compile some info on improving aerodynamics on CRX's, because I haven't see any info of that type anywhere..

Ass$nyper

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by inh &raquo;</TD></TR><TR><TD CLASS="quote">

Im not going for 200mph as my end all goal. I'm just seeing what things I can do to help it along and see how close I can get.

I was also hoping to compile some info on improving aerodynamics on CRX's, because I haven't see any info of that type anywhere..</TD></TR></TABLE> Ah ok, well try searching a ton and reading in the RR/AX forum.

I know alot of the faster track guys have some areo work done.

inh

will do, thank you =]

94 Supra TT

I have done some engineering work on a land speed motorcycle. A 100ci turbocharged v-twin pushing 380rwhp.

Their main concern on the aero side is downforce, and getting more downforce may increase your coefficient of drag. So you might want to look into that and maybe adding weight.

You get to a point where you have the soo much power, and your spinning your wheels fighting for grip.

So if your starting from scratch, work on getting reliable power.

inh

Updated my first post with my findings for tonight =]

Also started looking in to coast down tests. When I'm back stateside I want to do my best to do before/after coast down tests to determine effectiveness of any mods =]

edit:

just saw the above post.. Hopefully, traction isnt too big of an issue, but I hope with an LSD and some speed based boost control to have most traction issues taken care of, though I can see what you mean about issues at higher speeds...

njn63

The mirrors are a huge source of drag so eliminate them. Also close up all gaps as much as possible (make the gap between fender/hood smaller to prevent air flow).

I remember reading tips from a Geo Metro (of all things) that went pretty fast at Bonneville but I can't remember right now what magazine that was.