Anyone ever find a drag coefficient for our cars?

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Ponydrvr72

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No I havent either, but i know a 70-J code Torino was the first factory car to break 12 seconds with out any Mod's,and is listed as the second fastest factory car of the era behind the 427 Cobra.

 
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Mostly curious, but I've never seen one.

To add to the question, what is the top speed verifed by GPS that anyone has seen in a 71-73 fastback?
This site estimates it at 0.5 which is not great. Can't vouch for accuracy.

http://www.automobile-catalog.com/make/ford_usa/mustang_1gen/mustang_1gen_mach_i/1971.html
Where is the boss ? hehe...1971 Boss 351 jumped from a standing start to 60 mph in 5.7 seconds and ran the quarter-mile in 13.6 seconds. In a Motor Trend test from 1971...Stock it beat the big block 429's...Plus im not sure where they figured out the top speeds..But thats all relevant too who orderd it with what rear end gears ...lol...They need to show..This car with this gear..ran this fast."Or should" seems like they just doing a little math and no research....lol...351 4v with a 275 is going to have a better top speed than some one with a 3.25 like mine...Btw..Mine all stock as a rock would run 130 mph before i ran out of rpm's..With original factory carb and manifiold.

 
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Ponydrvr72

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LOL. My Jeep Cherokee is nick named 'the flying brick'. Only a parachute would make the drag coefficient worse.

I owned a 78 Jeep cherokee 360-2V,holly carb, dana 44's. was one of the best sounding stock engines i ever heard. broke the frame in a few places on a logging road,then the tow out by my friends F-250 finished her off.:(
 

Mister 4x4

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Before I became a member of the '71-'73 movement back in Aug 2010, I was getting ready to finally put a '78 Wagoneer's AMC 360 into my '80 CJ-7, along with an '82 Wagoneer's TC-727.

Let's just say I got distracted, since the 360's still on the engine stand. :D

 
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When I was in college, I found a book in the library that discussed traction and hydroplaning. Part of the research testing was done with a 71-73 Fastback--can't remember what year specifically. But pictures in the book showed the car at speed from a "human perspective" as well as from the "road's perspective". The human perspective photo is how I knew it was a Mustang and it was labeled as "130 mile per hour test pass" or something to that effect. Next to it, was a picture of the tire contact patch over a piece of glass of the car passing at 130mph. Couldn't tell you the name of the book anymore or how I stumbled onto it--especially since I studied "Business" in college.

 
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Neat memory there!

Aerodynamics not withstanding, I have the gear ratio and power band peaking just about right for a top speed of better than 150 mph. But without a legal place to run a top speed test, I've been too timid to break 135. It was still pulling hard, but the front end was heading toward being a bit on the spooky side.

 

Mesozoic

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Ummm, this is slightly incriminating, but worth mentioning. Regardless of what the drag coefficient of a '71-73 Mustang actually is, I logged 172 mph on a local road somewhere in southern Arizona. I was not alone either, my friend and I were both tuning our 4R70W transmissions, particularly the overdrive gear and lockup behavior in 4th gear. I was actually shocked! There was plenty more gear and power left to go, but that was as far as I pushed it in order to tune my lockup converter scheduling in 4th gear.

I was particularly surprised that I was able to out-accelerate my friend's Falcon with a turbocharged 302, similar weight. Speeds were recorded using an onboard Garmin GPS unit since tuning requires better accuracy than my stock speedo.

As one of my co-workers has said before, it's possible to make absolutely anything fly, regardless of how bad the aero is on it (I work at an aircraft design and development firm).

 

Finmach

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MuscleCar Review "25 Fastest Fords" article

Specials;

'65 Shelby 427 12.20 / 118 (slicks

'70 Boss 429 12.30 / 112 (slicks

"stocks":

1) '62 Shelby Cobra 260.......12,90 @ 114..........4 spd.

2) '66 Shelby Cobra 427.......13,20 @ 110..........4 spd.

3) '68 Cougar XR7 GTE 428...13,23 @ 103,39.....C6

4) '69 Boss 429....................13,27 @ 107..........4 spd.

5) '70 Torino Cobra 429 scj...13,30 @ 106..........4 spd.

6) '71 Torino Cobra 429 scj...13,30 @ 106..........4 spd.

7) '71 Mach 1 429 cj............13,40 @ 105...........C6

8 ) '63 Marauder S-55 427....13,40 @ 105,7........4 spd.

9) '70 Boss 302....................13,43 @ 103,22.......4 spd.

10) '68 Mustang 428..............13,56 @ 105,62......4 spd.

11) '63 Galaxie 500 2dht 427..13.60 @ 107..........4 spd.

12) '69 Mach 1 428................13,69 @ 103,4........C6

13) '70 Mach 1 428................13,80 @ 103...........4 spd.

14) '71 Boss 351...................13,80 @ 104...........4 spd.

15) '65 Shelby AC Cobra 427..13,80 @ 106..........4 spd.

16) '64 Shelby AC Cobra 289..13.80 @ 112..........4 spd.

17) '69 Shelby GT500 428.......13,87 @ 104,52.....4 spd.

18 ) '69 Cougar ht 428cj.........13,93 @ 102,38.....4 spd.

19) '69 Cyclone 428cj.............13,94 @ 100,89......C6

20) '69 Fairlane Cobra 428......13,96 @ 101..........C6

21) '64 Galaxie 500 2dht 427...13,96 @ 106,80.....4 spd.

22) '70 Cyclone Spoiler 429scj..13,97 @ 100........4 spd.

23) '66 Comet Cyclone 390......13,98 @ 103,8......C6

24) '65 Mustang ht GT 289.......14,00 @ 100.........4 spd.


PS. I've got the drag cofficiency somewhere in my files. Was used & determined by some drag team back the good ole day. I'll try to find it.

 
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MotoArts

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"stocks":

1) '62 Shelby Cobra 260.......12,90 @ 114..........4 spd.
Or, so they say :s

Dad's 260 Tiger only mustered, IIRC, a 16.4-ish @ somewhere in the mid-80 range back in the early '80's. Close ratio toploader (way too tall 1st gear for launching), a whopping 150 advertised HP and near zero traction didn't help... wound up the springs and wheelhopped BAD if it actually did get any (needed Traction Masters). With it's current (ahem, installed in the early '90's) Dunlop "big" rubber on it, it won't spin tire. Period.

A 15.99 woulda been cool that day.

I'll have to dig up that Keystone Raceway time card. It's probably still in the console.

Car was so stock at that time, probably still had its original antifreeze :)

And that I can vouch for.

Good stuff, all. Neat topic. I imagine that the vertical taillamp panel on our '72-73's added more drag than any other component.

Wonder if someone like Dark Horse Racing or any Bonneville racers has any info to view? Would be interesting to see, just for fun.

 
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Jeff,

When I went back to the local Tech College to take the upholstery class the teacher in the automotive repair was into Bonneville racing. His car was a Mustang II not one of our Mach 1's. He was a member of the 200 mph club and his engine was like 235 ci. He held the record for the CI class he was in. He was running a GM engine that was made up of donated parts from racing friends in NASCAR.

With the correct added equipment I would think a 71 - 73 could go over 200 easily with a strong engine and correct gears. Don't forget they run special tires for high speed they have very little tread to make them not go crazy with the thick tread walking you see on street tires. The street tires tend to throw the tread off at high speed.

He is the guy that really proved to me that the NASA scoop design works. He had friends that work at Ford in Atlanta at the wind tunnel. They gave him the shape to use to incorporate a NASA scoop into his Mustang II. The hood he was running had one of the tall scoops like the Pro Mod guys run. So he went to Bonneville and took both hoods. He made some passes with his old hood and it was doing just fine. He runs a programmable fuel injection not a carb. He took the Pro Mod hood off and put the NASA hood with the scoop flat on the hood similar to the 71 - 73 and made another pass and melted the pistons out of the engine it got so much more air. So the NASA hood design does pull more air in than the tall hoods if done correctly. Don't know if ours is correct or not but you could tell with some sensors and high speed runs.

I don't want to read an article about someone crashing in Tenn. after hitting a possum.

There were high speed trials just south of Charlotte in Laurinburg, N.C.. They ran over 200 mph there but I think it got closed down in 2012. It was a WWII air force base. You might do some checking with ECTA the East Coast Timing Association on where you run safe, they ran the events there. The company I worked for had a division there called Scotland Mfg. made heavy truck oil filter cases, deep draw.

Your tires and wheels have to be approved to run in any of the trials here or Bonneville. I help build a streamline for Bonneville. You have to do several low speed runs on the short track to show the car is safe. Slow is over 100 and gradually work your way up. You cannot just go and take off down the main course. I have personally never gone over 170 and that was in Nov. at the Charlotte track it felt slow. They told me it always does until you hit the wall. When I started to pick up my speed they pulled me into the pits and did a tire check before I made it to 170. Just getting the feel of the car when time was up.

David

 

Duncan Mach72

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Regarding the aerodynamics, the shallow angled rear window/deck coming smoothly off the roof and the flat rear panel are absolutely the best parts of the car. The worst is almost certainly the massive amount of grille/intake above & below the front bumper. Also the underside of most cars is usually bad for drag as its so untidy, so lowering the front or having a deep spoiler is always good because you are keeping too much air from getting under there.

I plan on blocking up the lower intake on mine with some aluminium sheet. Painted black it should be pretty much invisible in there. Also I have a grand plan to lower the front edge of my cheapo aftermarket fibreglass spoiler a little more, probably with say a 2" deep lip of aluminium then fair this back to the lowest point of the valance or even (preferably) back to the rad support. A lot of cardboard templates required!

I think Finmach got confused between aerodynamic drag & drag racing...that's excusable in his case!

I'd love to have the nerve to run my car over 150mph but it hasn't got the gearing, I think 125-130 will be about it and also I don't have tyres that I can trust at the moment.

 

captthundarr

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We, my wife Amy and I race standing mile land speed time trials under the East Coast timing Assc. ECTA. She drives, We currently hold 5 records in several classes. Top speed last year was 180.577 in our '91 camaro CD .34. Anyone wanting to run over 135 on "street" tires let me know so as I can get some life insurance on you, not a smart thing to do. The ECTA did run at Maxton, NC but lost the lease and the surface was falling apart. We currently run at the air port in Wilmington, OH. 2miles of like new concrete. They have a class for those who want to just make some runs without trying to break records. It is called Time Only, TO. Registration has just opened for the first race of this year. Butt loads of fun. Look up the ECTA for info. Rules are tight but it's for your safety. BTW .5ish CD is about right.

 

Mesozoic

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If I hadn't done the 4R70W, I would've most certainly done a Tremec 3550 or TKO manual transmission. The overdrive gear is one of the best mods you can make to your old Mustang. Just need to make sure that your transmission selection can handle the power and torque!

The sheetmetal blocking sounds like a very good plan. I'd be interested in seeing what you come up with. I recently taught myself how to design parts in Solidworks, which has made cutting metal on the waterjet infinitely simpler.

 
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