??Cobra's over 150mph

Chuck Nickloy · #1 (**permalink**) 05-13-2003, 03:19 PM

With all this talk about HP and how much un control the Cobra has at high speeds, Question?

Has there been, or is there someone, who had done any work on improving the Cobra's ability to stay on the ground "under good control" at high speeds? Is there any stuff??? available?

Chuck

M. Farcus · #2 (**permalink**) 05-13-2003, 03:24 PM

At TWS, I typically see 155+ based on rpm and tire size (speedo isn't accurate) in ERA FIA car...I keep the front low as possible without screwing up roll center and have added a small aluminum air dam under the nose....helps some, but a 90" wheel base car will always be twitchy....using too stiff springs will add to the twitchy feeling.

MF

flipper35 · #3 (**permalink**) 05-13-2003, 03:27 PM

I've seen dive planes on the front but nothing on the rear. Don't really know how well they work. I would think someone could fab a belly pan with a diffuser at the back/splitter in front.

Ricer wing/Civic front body kit? KIDDING!

Shelby (Peter Brock I think actually) made some mods and out came the Cobra Coupe. I've also heard they mada a front spoiler from a Coke machine back in the day.

Chuck Nickloy · #4 (**permalink**) 05-13-2003, 03:36 PM

I have been playing with a couple of ideas revolving around the air dam and the coupe "hole in hood". The nostrils of the Cobra (oil cooler hole and cooling hole) gulp air and float the car, I think.
Would diminshing this function do much? Is is possibe to somehow get some suction under the car to help keep it on the ground and to increase pressure on the tires for traction?

Chuck

Chuck Nickloy · #5 (**permalink**) 05-13-2003, 03:40 PM

MF, do you have a pic of your air dam? Post or e-mail me Please thanks.
Chuck

Doug Axelrod · #6 (**permalink**) 05-13-2003, 03:58 PM

The Oltoffs have a front spoiler for their SPF.
Guys, care to comment?

rocket man · #7 (**permalink**) 05-13-2003, 04:27 PM

By using a fine stainless steel wire mesh, I have been able to cut off the air flow through the front openings and picked up almost 3 mph in the quarter mile by doing so. It also helped the front end from becoming "light" so to speak. I do have a "wing" on the back of my car which greatly assists in keeping the car "planted" as I almost always go over 150 mph on each pass down the drag strip. If the track is really slick, I have even raised to angle of the wing (approx 5 degrees) to assist - and it does. However many of you will probably not want to install such an item - as it does change the appearance of the car, function over form.
Rockey

BANDIT 1 · #8 (**permalink**) 05-13-2003, 05:01 PM

You need to talk with the Olthoffs, they know all...

tyfaim · #9 (**permalink**) 05-13-2003, 07:01 PM

They know all?

RallySnake · #10 (**permalink**) 05-13-2003, 07:03 PM

Hey Rocky,

How about posting some pictures of the Rocket machine? Sounds like quite a ride!

Paul

Chuck Nickloy · #11 (**permalink**) 05-13-2003, 07:04 PM

Rocky,
Can you post some pics???
Chuck

Jahred · #12 (**permalink**) 05-13-2003, 07:12 PM

OK, this might sound dumb, but some thoughts on this.......anybody tried it??

What if you set the hood of the cobra so it is either raised an inch and a half or two or so that trapped air can raise it naturally at high speeds by the same amount.

The "Hood" would be a huge air damn, the increase in slope would decrease wind resistence on the windshield, which is too perpendicular and the opening would prevent trapping of air under the hood of the car.................somebody give that a shot at speed...................thoughts?

John A. Simpson · #13 (**permalink**) 05-13-2003, 09:35 PM

Hi Chuck,

People used to shim the rear edge of the hood open about one inch on cars used for drag racing years ago. Might work on the Cobra, the guys at HDR in Montana have hood vents similar to the mid 60's XKE, maybe they can comment on high speed stability. Here's one of their pictures. Hope they don't mind me stealing a pic for from free press.

rocket man · #14 (**permalink**) 05-14-2003, 07:54 AM

trying to attach a picture

tyfaim · #15 (**permalink**) 05-14-2003, 09:40 AM

John, thats a really nice idea, I like that louvered hood!

Chics LI · #16 (**permalink**) 05-14-2003, 10:11 AM

John,
That hood shot is of my car which Rick uses on his website for HDR. If you check my gallery there is also a front shot showing two small spoilers (actually vortex generators is what they are known as on aircraft). The idea for generators was to disturb airflow going over the hood and direct it to hood scoop, sort of a ram air effect.
The louvers are supposed to serve a duel purpose of allowing more airflow through engine compartment and allowing for additional hot air removal from engine bay.
I haven't had that much seat time due to work schedule and low miles so far on car, engine breakin is still ongoing. Hopefully I will be abl;e to get some help soon which will allow me to use car more. I had hoped to bring it to Carlisle this year but can't take the time off.

Tom S.

Rodney · #17 (**permalink**) 05-14-2003, 11:40 AM

Very sharp Tom.

rdorman · #18 (**permalink**) 05-14-2003, 12:04 PM

It was an attempt to help the cars aerodynamics.

DV makes a rear lip spoiler for these cars. Don't know how well it works but..........

Here are things I have heard work:
- reducing the front intake area. Like the screen idea. That is not the first time I have heard that. I seem to recall some factory racers with no ducts next to the turn signal lamps. Just to big of a mouth!
- give the front air someplace to go (remember the turd?) those little side vents are not going to cut it!
- front air dam as wide as possible to cover up the front tires.
- side skirts
- belly pans
- laying the windsheild back. They even used a trick where there was only one bolt, and it was left loose, and a spring so at speed the windsheild would lay back but when sitting it was at the stock angle
- flip that hood scoop around
- jack up the rear of the hood or mount it with pins that sit above the hood so it will rise up with pressure (better to keep it down in the first place.
- wings, of course! Although a 'tail' might work if it was long enough. Chapperel cobra anyone!
- hard top or wind diffuser behind the driver.
- running with the side curtains in but no top! go figure!
- increase the rake
- putting a Daytona Coupe body on it!!!

Long and short of it, a brick has better aerodynamic charactoristics

You will NEVER catch me doing 150 in mine! Don't know that I have been over 110 yet. I will if I ever take it down the quarter mile though!

Rick

rdorman · #19 (**permalink**) 05-14-2003, 12:08 PM

I forgot to mention that lifting the rear of the hood or louvers at the rear will only help so much. The base of the windshield is an area of very high pressure as well. Granted with no changes the pressure in the engine compartment will be greater than that at the base of the windshield so it will help. Keeping the air out is a better solution. Just an opinion! Haven't done a single one of these things on my Cobra and probably never will. Now if I was building a strickly racer............... Also, the front appears to be a bigger offender than the rear, start there. I have considered building a scale windtunnel and playing with the car. Now all I need is spare time!!
Rick

flipper35 · #20 (**permalink**) 05-14-2003, 01:29 PM

There were some cars with openings behind the mouth, but in front of the hood. Makes more sense to extract air there rather than in a high pressure area.