red6speed

I hit 146 one time getting to redline in 5th gear and still pulling and had to slow down due to traffic approaching (rather quickly!). Did this with 100% stock 03 except had OEM wing on it, did this help to create downforce? I thought it felt extremely stable for that speed..any thoughts?

bug230

146mph + traffic = dipshit!

SiGGy

the spolier is for looks only...



doing 146 in traffic with shitty/undersized stock brakes is stupid... not to say it would be smart with better brakes... but the cls wont stop well from that speed...

mantis23

It raises your drag coeffecient.

BlueCLS6

Not sure on the CL but a lot fo atermarket spoilers actually reduce the drag coeficcient. It keeps the streamlines flowing straigh and smooth rather than running down on the trunklid creating friction.

03CLsPunisher

it does not help, only looks nice. it actually might make the aero worse.

Jens H.

Like most spoilers it is there solely for decoration ,A lamborghini Countach as an example could not attain top speed if the factory spoiler was installed .It simply added too much drag .Although some spoilers will add downforce most (including ours) lacks the needed shape to really accomplish anything useful other than decorative purposes.


Jens

RUF87

True, most wanna be sports cars spoilers are mostly for looks. They add weight and drag for the most part.

Most really don't add much benefit until your over 100 for the most part.

Ruf

bigman

and in order for an aftermarket spoiler to really make any difference, it would have to be designed in a wind tunnerl with our car to really make a difference.

red6speed

Wow from the looks of it, the spoiler is useless, thats what I thought but just wanted to pose a simple question about it, do not however appreciate the uneeded flames to my post simply because some people are too pussy to test their 30K car. I did not feel that I needed to go into the details since that wasnt the question and I was not trying to brag, but the "traffic" was about .5 miles ahead and already doing 80 mph, this was done on a morning on a highway surrounding Nashville that has nearly NO traffic at all, ever. I would challenge anybody to find a better spot for high speed testing that is straight, built for high speed driving, and has nearly no traffic, besides a race track. Also, my stock tires are factory speed rated to 149, but I bet we all knew that anyway. The brakes stock are fine for slowing down, no fade at all from that speed. Grow up and stop critisizing everybody elses "accomplishments" without knowing the whole story, this sort of deriding seems to be all too prevalent on this forum that is supposed to center on cars, modifications, and people doing things with those aforementioned cars.

EricL

I'm not too sure that the spoiler is doing "nothing." (This is my opinion.)

At a minimum, it is cleaning up the boundary layer air at the back of the car and the reduction in turbulence will help the lift at the back. You might get more help with lift at front AND back with the car lowered.

As for the "safety" issues: The braking distance goes up in relation to the SQUARE of the velocity (unless you are running a F1 car with aero devices). The distance to stop from 150 MPH can be over 600 feet depending on brakes, surface, wind velocity/direction, etc, etc.

1killercls

I got mine SANS Spoiler.

Red-CL

03CLsPunisher

btw, the spoiler(areo package) on the G35 is tested in a wind tunnel and it reduces the CD.
"Drag hinders motion. It can diminish the power of the strongest engine and dull the driving experience. So the G35 Sport Sedan was sculpted with clean, purposeful lines. Air was channeled over, under, and through the car until the coefficient of drag was reduced to a mere .26 with the Aero Package (.27 without)."

"There is a force that seeks to pry your car from the road. Its name is "lift" and the G35 Sport Sedan was obsessively finessed to reduce its influence. And, with the addition of the Aero Package, eliminate it altogether.* Go ahead and fly, but do it with all four wheels on the ground."

"Function and form strike a perfect balance with the optional Aero Package. It includes a functional rear spoiler and underbody diffusers that reduce the vehicle's overall lift to zero and drag coefficient to .26. We couldn't imagine a more dramatic finish to the car's silhouette. "

ok you get the point

Jens H.

Well you found your answer the spoiler is probably just decoration but it does look nice .

Testing your 30 k car on public roads that are probably limited to 65 MPH could be hazardous to your license and the other occupants on the road .I am certain you took some precautions such as insuring you were more or less alone on the road and wore your safety belt .However driving at the speeds you indicated is a blatant violation of state law and as such not an "accomplishment" .

This is a public forum and as such if you choose to post a question it is hoped that someone will be able to give you some answers however if you choose to post about ultra high speed road antics you will also earn the ire of those who feel your "accomplishment" smack of out and out foolishness.

We all take chances with our cars after all it is human nature to be curious about this most favored of man's inventions but do realize that there are those who would rather you try your machine out in a controlled environment such as a race track instead of a public road where these people may have friends or family sharing the road with a person seeking to discover the real limits of a particular machine .This is not flame friend just some observations .

Jens

red6speed

I perfectly understand your points and appreciate your concern, as such, I have my own concerns about this sort of stuff, that is why I only did it once, and have never even been close to attemping it again, recognizing all of your points and completely agreeing. I felt that that particular run was the least risky of the possibilities, and I was proved correct on that attempt. Yet note however, that I did choose to put the word accomplishments in quotations, signifying that I do NOT view my top speed run as such (as others surely may), and thus my anger with the people with pointless flames having nothing to do with my question and who would rather hear their own uninformed minds blabber about something tagential to the topic. And yes, this is unavoidably a public forum, and therefore has the inherant fault of hearing what every person has to say, regardless of experience or knowledge.

Jens H.

Well public forums are both blessing and curse .Like I said I am sure you were cautious in your effort .Having personally driven on the unrestricted Autobahn in Germany (will be going again in February) I can certainly understand the curiosity about top end performance .Sometimes these forums can be frustrating however oftentimes they are an interesting reality check because people will speak their mind .

Jens

pimpscls

nice 146 mph how long did take u to stop, and btw i think the spoiler is fo show

RUF87

Dang! I knew there must have been a reason for all those speeding tickets. I thought I was still in Germany. I mean with all the BMWs, Mercedes, Audis. etc around these parts . . . :P

And note, even though there are sections of the Autobahn that are unrestricted, there are common sense rules that come in to play. Such things as weather, traffic or road conditions may warrant that you maintain a safe speed. So you can still get ticketed for failing to maintain a safe speed.

But is sure is fun to press the gas and let it rip on those nice stretches . . . until some Porsche, big Bimmer, Benz or othewise blows past you . . . and your doing 220-230

Ruf

Jens H.

Germany still maintains it's no speed limit autobahns in many sections however the recommended road speed is set at 130 KPH.All other countries in Europe enforce speed limits on the their highways .Interestingly enough recent changes in Austria and Switserland have brought about possible increases in speed limits on their highways from 130 to 160 KPH. Can't wait to move home .

Jens

JRock

Which one's home for you? I always thought you were Skandinavian. Guess that's just cuz a guy named Jens I grew up with in high school was from Sweden.

Jens H.

I was born in what used to be called West Germany in a small city in the north called Holzminden .A lot of people think I am from Sweden but I was only there on vacation .I did live in Denmark for some time in Copenhagen .

Jens

JRock

awesome

NSX-Tuner

Regardless what some numb skulls claim, the OEM spoiler does provide some down force at high speeds.

Jens H.

In order for a device like a spoiler to work it must have the correct shape and angle to provide any measurable downforce .I might be a numbskull (I never claimed to anything else so why not a numbskull ?) but even this numbskull can see that a CL spoiler has no real airfoil shape nor is it installed in any fashion that could provide any sort of useable downforce .But it does weigh about ten pounds so it does add some weight to the trunk so maybe that could be defined as downforce??????

Jens

Titand19

is there really traffic in Nashville, or are you just making an excuse cause your spoiler didn't let you go any faster?

EricL

Jens, a spoiler -- as exists on the CLS -- can remove lift and thus increase downforce. Just straightening the airflow around the rear of a car can help reduce lift. As such, it doesn't need to have appreciable angle -- or need a specific contour -- relative to the air stream to act as an "anti-lift" device.

The following paragraph taken from "Race Car Design Tips" could be useful:

"..Worse still, once the air makes its way to the rear window, the notch created by the window dropping down to the trunk leaves a vacuum or low pressure space that the air is not able to fill properly. The flow is said to detach and the resulting lower pressure creates lift that then acts upon the surface area of the trunk. This can be seen in old 1950's racing sedans, where the driver would feel the car becoming "light" in the rear when traveling at high speeds. See the diagram below."



If you put a "flat" wing at the rear of the vehicle, it will generally reduce the drag AND lift. The 92-93 Maxima SEs has a factory spoiler of design similar to the CLS (with add-on spoiler) and it did help reduce rear end lift (I owned a 92). There are more examples as well... The example of the G35’s spoiler (reducing drag) should prove instructive as already pointed out in an earlier thread.

Finally, here is a longer article on a couple of other cars and might be of some interest to some members:

http://www.autospeed.com/cms/article.html?&A=1055&P=5

Note: the page contains a lot of pictures of airflow around a WRX and LS400.

“…In three-box cars (ie booted sedans) it is always the case that most of the action is around the back of the car - especially in the transition from roof to boot. Gently sloping rear windows will allow attached flow to be retained onto the boot lid, while C-pillars that are curved in plan-view will aid the flow of air from the side of the car onto the rear glass (and then down onto the boot lid). A clean exit from the top of the boot lid will reduce drag further, while boat-tailing (the car narrows at the rear in plan view) will also reduce the size of the wake if the sideflow remains attached.
From a lift perspective, flows that wrap over those upper curves tend to create lift (the vast majority of sedans have a positive rear lift co-efficient, with advertised "downforce" improvements more often meaning "reduced lift"!). However, if the attached airflow can be retained on at least the trailing end of the boot lid, wings can be effectively used. Otherwise, a spoiler that disrupts the attached flow around those upper curves is a better bet


There are no SIMPLE right or wrong answers regarding this issue...

civic4982

uhhh still pulling? I thought speed gov. stopped at 146 MPH?

NSX-Tuner

One numbskull to another...

Close examination of the OEM rear spoiler will reveal the following:

• Top surface is nearly flat with a very slight curve front-to-back
• Bottom surface is very curved.
• It has a tear-drop shaped cross section, fattest on the leading edge.
• It's mounted like an upside-down airplane wing.

Its shape qualifies as an airfoil so it will provide some aerodynamic down-force. Granted, it doesn't have the ideal shape. Also, it's mounted flat when it should be at a much steeper angle. Never the less, it will provide some down-force at high speeds.

Jens H.

Ah so like I said I am nothing more than a numbskull LOL but I read that book that was quoted as well and I have one other little tidbit I forgot to mention .I asked in school when i had the chance to speak to guy who has the delightful title of "model engineer" .Model Engineer is Hondaspeak for" guy in charge of this car ",I asked him then (few years ago) about the spoilers they offered on the CL and the TL."Just a decorative item" he said .I guess I should have said that in the first place .One of the advantages of going to Honda schools is that the engineers like to pop in every now and again and you even get them on the phone from time to time when problems arise .If there is time they entertain questions like this from us mechanics .

Jens

mrsteve

iTrader: (1)

red6speed

Wow, this thread has proved to be informative, with viable points on either side of the argument, I do agree that the wing appears to be a quasi-airfoil, and being a pilot myself, will tend to lean toward the useful nature of this wing while noting that it is not that efficient or built correctly to provide the most downforce, but the shape does not lie and given my aero courses from the Navy, I can't help but feel that at 140 there is enough air flow to actually do something, given its design.

As for the speed governor, I did read that it was governed at 146, I was still pulling at 144 when I decided to let off, I assume that I hit 145 or 146 given the reaction time of looking down at the speedo while watching the road, so I really don't know if it is governed, anyone topped out a 6 speed? But yes, I was in fifth gear near redline, don't know if 6th gear would have pulled more (especilly because of my crappy spoiler )

Nashua_Night_Hawk

As note by EricL, and cls6sp03, the shape of the rear spoiler is like an inverted airfoil (wing). Thus, one can conclude that at extreeme speed say above 120 MPH, this will act to reduce lift as opposed to the natural job of an airplane wing to increase lift!.

Now, for low speed ( <120 MPH) it is "Just a decorative item" as noted by the Honda Engineer. That is true too.

Therefore, both side of the coin are true.

Finally, does it reduce lift and drag or only lift? I lean to the fact that it reduces only lift.

If you check Nissan 04 Maxima documentation, the rear spoiler, "a small flat lip" (part of the Driver Prefered Package) will reduce the drag coefficent from 0.30 to 0.28. Does it reduce lift, maybe not. However, reducing drag coefficent is more useful than reducing the rear lift since it would improve MPG and top speed and has a positive effect each time the maxima is moving.

Nashua.

Jens H.

well if somebody wants to loan me their CL/S i will be glad to do some actual testing in February .I'll be over in Europe (Switserland and Germany) so I will have some time to do some road testing at 120 plus to see if the car feels any better .I would prefer a car with Brembos I am not so sure about the stock stuff at those road speeds .


Ok Ok just kidding

Jens