Top end Bonneville straight line speed poll

[learical1]

Everybody knows that one of the big advantages to the 'Bird and Daytona was the wing.  It added stability to the cars on the high banks at Daytona and Talledega, allowing faster lap times.  However, in a straight line, the drag created by the wing and its supports probably slowed the Mopars down slightly.  So, at Bonneville, which of the aero cars would give the highest top speed?   I gave you a choice of engines on the FoMoCo products, because while the tunnel-port 427 may not have had the 'off the corner' torque of the Boss 429, they were very similar in overall horsepower.  I also gave everybody a chance by including the SuperBird and Talladega, when most schools of thought lead us to believe that the Daytona was superior to the 'Bird and the Spoiler II was superior to the Talladega in a straight line. Please give your reasoning.  

[learical1]

I chose the Spoiler II with the Boss 429.  This car often sat on the pole at the big tracks.  I'm not sure if the Boss 429 is really superior to the 427 tunnel-port in top end performance, but I believe it has more potential, so I went with the Boss '9.  However, if I was building a Spoiler II for Bonneville, I'd go with the tunnelport just because it's an easier fit.

[41husk]

I voted for the Daytona, first to break 200MPH, and I like them best

[Ghoste]

I voted Daytona because I think its package is slightly better than the Plymouth and I think the Fords had about hit their max on the big ovals.  I think had they gone much faster they too would have been looking for extra downforce at the back.

[Indygenerallee]

OOOooh That's a tough one....... Daytona with a elephant of course!!! 

[tan top]

Daytona  , but superbird is the next closest  , had almost as good aero as the daytona , but not quite

[learical1]

Just a reminder:  downforce keeps you 'glued' to the track.  Up to a certain point, the more downforce you have, the less you have to slow down for the corners.   Too much downforce = increased drag = slower speeds.  Not enough downforce = no traction in turns = slower lap speeds.  But I'm talking straight line, ultimate top end 'Bonneville' kind of speeds, not lap times.  I changed the thread title to make things a bit clearer.  I also allowed for vote changes, in case you change your mind.
BTW, I'm waiting for Doug S (aero426) to chime in.  I'd like his take on this.

[learical1]

And I'd really like C5HM's opinion, too!

[Ghoste]

I'll stay with my answer for now.  My reasoning for it being that while agreeing on the downforce and drag, remember the wing on the Mopars adjusted so you could set it for the right amount of downforce.  The shape of the Ford at speed was going to eventually create lift in my opinion which would be worse for straight line.  Now your question taken literally, as set up for NASCAR makes it a different thing.  I'm taking your question to mean NASCAR ready but running on the salt with minor tweaking to set a record for straight line top speed, NOT which car is faster in a straight line if you drove it right from Talladega to a salt flat with no changes.

[hemigeno]

A couple of dumb question here:

Aren't most of the participants' top speeds significantly limited by their vehicle's traction?  Seems like you're going to need a certain amount of downforce to keep the rear wheels planted even while going in a straight line - meaning a properly balanced package of nose and wing on a Daytona probably still gives it an edge.

Also... didn't the #71 Daytona (the actual car now owned by Tim W.) and Bobby Isaac set new speed records at Bonneville after the '70 season was completed?  If I'm not mistaken, don't some of those records still stand?  I'd be interested to know if the Ford/Mercury aero offerings were sent to the Flats back then also.  From what I remember from talking with the (now late) Harry Lee Hyde Jr., the #71 still had more speed to show -- but exhaust leaks and time kept them from doing more.  They broke the exhaust after a spin during one of Bobby's runs.

I haven't really heard Bonneville stories from any blue oval teams, although they may have done a whole lot and have maybe even broken some of the K&K team's records too.  

[odcics2]

If you go by the HP of the engines and the drag numbers in the real world, I bet it would be close between the 426 Daytona and the 429 Mecrury.

Keep in mind the wing is adjustable for downforce - just enough tilt to keep the tires on the ground...
The Merc would need the rear spoiler tweaked to maximum performance. (note: not lowest drag, nor max. downforce, but a combination)

It's a fact that a wing produces less drag for the same downforce as a rear spoiler.

429 had an edge on top end HP, since it was a newer design.   Daytona has lower drag - per aero tests run by Ford!! (and can be seen on the DSAC web site)  

Glotzbach ran 199.466 to grab the pole for the first Talladega race in the #88.  LeeRoy Yarborough was a close second.  Neither car competed due to the tire boycott.

 
This is a good question!  

 

[learical1]

Now your question taken literally, as set up for NASCAR makes it a different thing.  I'm taking your question to mean NASCAR ready but running on the salt with minor tweaking to set a record for straight line top speed, NOT which car is faster in a straight line if you drove it right from Talladega to a salt flat with no changes.

Yeah, I could have worded it better.  I just didn't want anyone to think I meant stock street cars.  A 351 W Spoiler II isn't going to cut it.  I should have said something to the effect that you take 6 early 1970 NASCAR Aero cars (with side glass),  set them up to go in a straight line (no worries about turns), and let them loose at Bonneville.  Which car will have the highest 'flying mile' speed?

[odcics2]

A couple of dumb question here:

Aren't most of the participants' top speeds significantly limited by their vehicle's traction?  Seems like you're going to need a certain amount of downforce to keep the rear wheels planted even while going in a straight line - meaning a properly balanced package of nose and wing on a Daytona probably still gives it an edge.

Also... didn't the #71 Daytona (the actual car now owned by Tim W.) and Bobby Isaac set new speed records at Bonneville after the '70 season was completed?  If I'm not mistaken, don't some of those records still stand?  I'd be interested to know if the Ford/Mercury aero offerings were sent to the Flats back then also.  From what I remember from talking with the (now late) Harry Lee Hyde Jr., the #71 still had more speed to show -- but exhaust leaks and time kept them from doing more.  They broke the exhaust after a spin during one of Bobby's runs.

I haven't really heard Bonneville stories from any blue oval teams, although they may have done a whole lot and have maybe even broken some of the K&K team's records too.  

The car used at Bonneville was not NASCAR legal.  It was a USAC sanctioned run.  

[hemigeno]

The car used at Bonneville was not NASCAR legal.  It was a USAC sanctioned run.  

I understand that completely... the #71 in salt flats trim had no driprails and other non-NASCAR modifications.  No one said anything (initially) about NASCAR rules applying though, I thought...  

[learical1]

A couple of dumb question here:...

Also... didn't the #71 Daytona (the actual car now owned by Tim W.) and Bobby Isaac set new speed records at Bonneville after the '70 season was completed?  If I'm not mistaken, don't some of those records still stand?  I'd be interested to know if the Ford/Mercury aero offerings were sent to the Flats back then also.  From what I remember from talking with the (now late) Harry Lee Hyde Jr., the #71 still had more speed to show -- but exhaust leaks and time kept them from doing more.  They broke the exhaust after a spin during one of Bobby's runs.

IIRC, what hampered Bobby and Harry more than anything else in 1971 was poor salt conditions.  Ideally for endurance runs at Bonneville, you want a 10 mile circle to run on.  That is almost like running in a straight line, the curve is so gradual.  Well, the salt was too wet in places to allow a true circle that year, and Bobby had to run a 10 mile flat OVAL, and he drove it like a dirt track, letting the back end slide out.  That does slow you down a bit. 

And, if you move all your ballast weight to the rear of a Spoiler II, you'd probably have more than enough traction for 210 + MPH.

[Ghoste]

As speeds increase though the blunter nos of the Mercury is going to come into play more and more.

[odcics2]

Now your question taken literally, as set up for NASCAR makes it a different thing.  I'm taking your question to mean NASCAR ready but running on the salt with minor tweaking to set a record for straight line top speed, NOT which car is faster in a straight line if you drove it right from Talladega to a salt flat with no changes.

Yeah, I could have worded it better.  I just didn't want anyone to think I meant stock street cars.  A 351 W Spoiler II isn't going to cut it.  I should have said something to the effect that you take 6 early 1970 NASCAR Aero cars (with side glass),  set them up to go in a straight line (no worries about turns), and let them loose at Bonneville.  Which car will have the highest 'flying mile' speed?

Hemigeno  - He added the "NASCAR" AFTER your comment and prior to mine!    

[Redbird]

Running under SCTA-BNI rules at Bonneville in 1970 in the Production class the contest is just between 2 cars, Superbird-Daytona. For the simple reason that one had to race with an engine design that was available in the car raced. For example Superbirds and Daytonas could have a Hemi or a wedge; 440, 426, 413, 400, 383, 361, 350 or even a destroked b-block, or stroked Hemi, B, or RB. Can't run a 340 in those cars in Production Class.

This means that a Mercury would get a 351 family motor and a Talledaga would get a 428 family motor. That is why there aren't any records by Ford bodies in the SCTA-BNI Bonneville record books in the Production class. A back in the day time puts Lindsley's Plymouth or the #71 car pretty much equal in top speed, Lindsley's car being a lot more stock-especially the front spoiler.

Today with the mega dollar motors in a SCTA-BNI rule car, the 426 cars win, because the rules are the same; in a Production class you have to run a "family" motor. Engine development is a lot better for the 426. Bring your wallet.

Stepping up in classes where a motor swap is allowed, back in the day the 2 hemi cars or a 429 Mercury. Engine development+aero for the 3 cars I think would be about equal at that time.

Weight is not your enemy at Bonneville. Aero, traction, and horsepower are. Fill any of the 3 cars with lead weight and their traction is about the same.

The rules are why it would be very hard for the tribute #71 car to get a record. Front end modified makes it a Competition Coupe. Not even close to a Production, Altered, or Gas coupe classification.  Record for CC is about 250 MPH in A class motor. Modified quarters would make it ineligible for the Competition Coupe class and a time only car. Mostly to say a very cool car.

NASCAR back in the day at the flats, 429 Mercury, 426 Superbird or 426 Daytona.

NASCAR 1969 or 1970 body today, either of the 426 cars, strictly because of engine development.

Just my opinion.

[Aero426]

The Spoiler II was a bullet on the ovals.   I don't think one has ever been run on the salt.     But I bet it would run very well. 

[odcics2]

Here is the Ford wind tunnel info from the DSAC website.  Larry Rathgeb has stated the hemi in the Engineering Daytona put out 575 hp during the 200 run.  These figures from Ford support that. 

[Ghoste]

Is that top speed an average lap speed or straightaway?

[tan top]

interesting thread  

Is that top speed an average lap speed or straightaway?

thats what i've always wondered !! with that chart  , think  could be lap speed , caculated by time !!
not straight line speed ,  pure speculation now   , but if you had a arrow straight strip of black top ,  10 miles long !! no power / speed  robbing   banking   etc etc wonder what the top end for all the cars would be , even the C500

what it comes down to as we all know  , is  can the motor make enough power  to pull  X amount of rpm  ie 6500 or 6600 6800  (((((  think ( not sure ) at the time that was the max safe limit sustained RPM for a Hemi ))))))   , with   2.94  or 2.76  rear gears  + tire hight ,  in high gear , ( fourth )  if the motor  not making enough power to turn that RPM in a given body style , & there is no more power in the motor  ,   make  the car cut through the wind better !

wonder what would of happened ir the Areo cars could have run with  twin four barrels

[Ghoste]

I've wondered because did they not obtain higher lap speeds at Chelsea's much larger than average oval?

[hemigeno]

I've studied the doc that Greg/odcics2 posted before, but something just jumped out at me...

How-in-da-heck did Ford get their hands on a Daytona to use in their wind tunnel on August 3, 1969, when the only one shipped up to that point was maxwellwedge's car (414619) that went to the Toronto Car Show?  The next one didn't leave Creative Industries of its own accord until 8/16/69.  Did one leave Creative's back lot late one night and get returned before the next morning?  

[Ghoste]

Maybe that one is the theoretical data test?