Veloce Raptor

And, in one post, Mark contradicts himself & validates my point.

PS: I understand WC quite well, sparky.






Professional Racing and Driving Coach

chris walrod

In Pro Atlantic, the car is weighed with driver. This is a result of the series making the cars as equal as possible (ala Danica P when she raced Atlantic).

Then there is the creativeness as to where to stick ballast, we specified this as well. Ballast must be placed at the driver CG, transversely on each side of the drivers belly button (using spec ballast plates in a spec location provided by the racecar constructor) therefore eliminating the advantage of a horse jockey driver.

multi21

But Chris, let's say a driver is heavy enough that he doesn't need ballast and is 20# over the minimum required post race weight in an Atlantic. What would the extra 20# translate to in lost time on a track such as Laguna with elevation changes and heavy braking zones?

BC

You don't even know the half of it man.

BC

Perris? I should go check that out. K1 speed in Carlsbad looks like a 28 or 29 fast lap. I was lapping at 30.5. Electric carts (laugh, I know - but its fun)

Miramar speed circuit, closer to my house, is a 29.9 fast lap on the new configuration. I just broke into 34. These are gas karts, however, which have less torque.

Veloce Raptor

OK, now you've gotten me thinking about Danica's belly button.







Professional Racing and Driving Coach

TrackDays247.com

FWIW (not much, maybe my butt isn't well trained) I can't notice a weight difference on track unless it is above 100 lbs.
Then the transitions seem a bit more wallowy, and the wheel effort increases.

1982 514HP 930 track car.

chris walrod

With a car such as the current Atlantic chassis that has tons of DF, at Laguna, lets say, lap time hasnt been much different between the heavy weights and the ballast users. That said, a short twisty street circuit certainly favors less weight.

Its hard to quantify this as all drivers (and teams) are of a different caliber. Given equal cars and driver talent, 20 pounds is significant.

Now that said, lighter weight is, perhaps, more sensitive in a lighter racecar as its a larger % of the sprung mass.

mark kibort

You didnt read post #10 did you?
You pushed the apple cart down the hill, not me.

Ill give you the cliff notes, since you are consistant with your level of comprehension.

If we are talking the same total weight cars then you are right, but if not then......... You came back with ..........." Not true". In the end, you were talking same weight, different distribution (center of mass), but since you made the statement of my post not being true, I assumed you were talking about driver weight over equal car vehicle weights.

In otherwords, I said you are right as long as we are talking driver and car weights. If not, (like Indy) its not true as a heavy paul tracy would have to run against a Danica Patrick and the overall weight would be unfair.

mk

Here the two original posts . VR vs MK



VR's Original Post:
Quote:
Originally Posted by Veloce Raptor
In an SRF or open wheel/formula-type car, driver weight is a major factor. In a sedan-type car, not so much, unless the driver is 500 lbs, IMO.



Then, my response:
Quote:
Originally Posted by mark kibort
Only if the class weight is with driver like speedGT/Touring. But, in Indy, look at the advantage Danica has with being 90lbs vs 200lb guys! 100lbs trying to get to 220mph is significant, in either a HP measure or rear wheel Torque!
(not to mention cornering and braking)
They should toss Mika into Danicas car for her races to make it fair for the big men of the series.


Then, VR came back with:

Um....not true. A hugely heavy drover is much worse for center of mass, etc. than ballasting to the same total weight, or than a light drover in very lightweight or underpowered cars, IMO.










What we have here is a failure to communicate!

Robert Henriksen

That's why we fitted a dry break fuel filler to our enduro 'spec' racer ford And a larger fuel cell, which meant we moved the drover 2" forward...

srf506

Hey Robert,
Moving the driver 2" forward in an SRF would probably give you a huge improvement in handling over the "stock" SRF, unless the additional fuel weight offset the gain? We used to run the 24 Hours of Moroso. Fun time. SRFs were like the LMP cars out there. Most of the other production-based cars might pull us on the straight, but we'd definitely get 'em under braking and in the turns. Additionally, we were so much more reliable than most of the others we spent a lot less time in the pits.

Most race engineers will tell you that the driver is the biggest PITA they have to design around. (Aerospace engineers say the same thing about pilots by the way ;-) ). You have to have a man-sized hole right in a place where the chassis really could use the stiffness which drives suspension compromises, the weight is up too high and it's in the wrong place for weight and balance, and you have to include a lot of clap-trap and compromises to keep him safe and in control.

dmwhite

lol, he's tubby but not THAT big...not that i have any room to talk

Veloce Raptor

He's "big boned". You...you're just...you.







Professional Racing and Driving Coach

M758

In theory the 250lbs driver will always be slower than the 150 lbs driver. The reason could be a straight 100lbs weigth difference or 100lbs of less than optimal ballast.

Now we don't race in theory so in practice is it much much more complicated. The best way to limit the advantage is to make class weight car + driver. In this way both cars could race at the same weight (maybe). If they do then most differences are eliminated, but what remain is were the 150lbs driver can put ballast to improve the car.

So in the end the 250lbs will never have an advantage, but rules and good planning can minimize most of the disadvantages. If you can get the disadvantages less than the driver variation you are looking good.

quickxotica

Yes, I was there on Saturday. First time ever. I only ran the Yokahama track. One 15min practice session, then a 20 min race. My best lap was 27.80s. I'm 6'1" + 175lbs. Only been on a kart twice in my life.

But...since my fastest lap occurred on lap-25 of the race, after 674 picograms of sweat had evaporated off my body, we can conclude that weight is more significant than hydration using the formula u = Wr^17 + (1/P), where P = pearshapedness. Q.E.D.

PS: Yes I had too much coffee this morning. But my first paragraph is true, and I agree it is a nice facility.