Drag racer needing a little help on aero.

[MiltonP]

Bumping for an update!  Just read the whole thread and looking forward to the results!

[cold85]

Well we are trying to be back on track in a few weeks we found a crack in the block so had to redo the short block. Pete @HED also spent countless hours on the dyno finding some power
He got it to 1950HP with the 88mm turbo



We also re wrapped the front




And one more vid from a win last year

[El Wayno]

Awesome motor vid. Love the red hot manifolds.

[fastman614]

That would be 330 ft  

The change will be very small at those speeds and the short duration of the run, but Aerodrag begins to influence trap speeds and ET once you get over about 60-70 mph, and he will be going faster than that for about 2/3'ds of the run if he is trapping at 140+

If it takes 20 hp for him to go 60 mph (which would not be unusual for that older body style) it would take 8x that hp to go 120 or about 160 hp, and about 180 hp just to over come air drag at 145 mph.

Larry

It has been a long time since I ran an early Dart (the last one was a 1974 Dart Sport with a 360 V-8, 4 speed, 4.56 gears etc) .....It was a low 12 second car in the 1/4 mile.... speed at about 108 mph +/-.....in ET bracket racing, this was not an issue.... consistency was....


What exactly you have to make it go 145+ in the 1/8 mile has to be pretty good - perhaps a pretty wild combination...

Are obvious body modifications allowed.... like "grafting" a Corvette front nose on to the car (with ALL due respect to our recently departed friend, Neil Thompson) If not, then you may want to take a real good look at the competitors who are out "mph-ing" you.... do they have obviously better aerodynamics than you?... There does come a time when it is time to say -what you see is what you get - at Bonneville, when any of us are suddenly faced with this reality, it becomes decision making time.... (or we get a "classic coupe and sedan" category put into place - resulting in about another 115 or more new classes in which to run....)

If you only have limited body changes at your "disposal", I would say that several of the suggestions - from making sure you have a positive forward rake, that the exhaust is blowing straight toward the rear of the car to an air dam being affixed to the front of the car are all good ideas.....

Good luck and thanx for asking us.... AND... DO let us know what you came up with that helped .... or even what you also tried that didn't seem to help.

[cold85]

Only a slight update we have been testing but having trouble putting much power down.  the car sits about 4 inches lower all around and is not nose high on the other end of the track like it was. Once we get the suspension dialed back we may have an idea how much the changes made.

[hotrod]

Unfortunately lowering the car for aero, changed your weight transfer dynamics on launch, so you are in trade off territory.
You might even go faster by adding a small amount of carefully placed ballast (or relocating components) to put more weight on the rear and to get the bite you need on launch.

Larry

[PatMc]

IMO (I'm only a 9 sec guy)...

Here's the problem I see.  Aero is poor use of time/money at 140 at the drags.

Years ago, we towed the Vette and the Pickup to LACR (rip).  At the time, both has similar power to weight ratios.  Both ran 11.6's? that night (slippery track from dirt blowing), but the Vette would go 121?, and the truck would go 114?  Now the truck has at least 3+ times the air resistance as the Vette so what gives?  The truck was a hair quicker, but about equal.  (It was one of the rare days that I raced against my wife; since we have kids if there is an accident, there is nobody to watch them).

Anyhow, it's the same issue as bad 60's yielding the same MPH as a good 60'.  The TIME you spend at over 100mph is very short compared to the time you spend getting up to 100mph.   Improvements on the big end aren't as effective as improvements off the line.

Spend your money on weight reduction, more data, seat time, 60's, etc.  There are pickups going 140+ at the drags (I'm stuck in the 130's so far), and nobody is going QUICKER with aero changes.  Faster, yes.  MPH doesn't win races.

[cold85]

IMO (I'm only a 9 sec guy)...

Here's the problem I see.  Aero is poor use of time/money at 140 at the drags.

Years ago, we towed the Vette and the Pickup to LACR (rip).  At the time, both has similar power to weight ratios.  Both ran 11.6's? that night (slippery track from dirt blowing), but the Vette would go 121?, and the truck would go 114?  Now the truck has at least 3+ times the air resistance as the Vette so what gives?  The truck was a hair quicker, but about equal.  (It was one of the rare days that I raced against my wife; since we have kids if there is an accident, there is nobody to watch them).

Anyhow, it's the same issue as bad 60's yielding the same MPH as a good 60'.  The TIME you spend at over 100mph is very short compared to the time you spend getting up to 100mph.   Improvements on the big end aren't as effective as improvements off the line.

Spend your money on weight reduction, more data, seat time, 60's, etc.  There are pickups going 140+ at the drags (I'm stuck in the 130's so far), and nobody is going QUICKER with aero changes.  Faster, yes.  MPH doesn't win races.

That is true  but we were doing the aero along with changes to help the 60 but the lowering of the car and moving of weight was to improve the 60. by being nose high and short ladder bars the car wanted to wheelie bad on a good track and moving weight forward to stop that made it spin

[Buickguy3]

  Add gear until it won't go any faster, then add horsepower, when the tires spin, add weight, when they won't spin any more add nitro.
    Doug  [I stole that from a previous post]

[cold85]

Made our first race it was hot and track was not great but made it to the semis car ran 4.93@152
http://www.youtube.com/watch?v=0rAPFcvLL-8&feature=channel&list=UL

pic from last year

pic from race day

still have work on suspension and some other stuff but i think we will go 160 pretty soon

[cold85]

still not 160mph yet but we have the front half back on track
4.71@152