JUIC3D

So I had a disappointing night last night at the track and I'm trying to make sense of what it was exactly that caused the decline in performance.

How much effect does a 10-12mph headwind at the track have on a car that routinely does 10.9-11.1@~127?

I'm not one to make excuses for my driving or the car not performing, but I am curious to know if that headwind is something to consider when the car doesn't run the times that I'm expecting.

Thanks in advance.

Dave-T

I would say that the head wind of ony 10 mph would have very little effect on ET and mph. How different was the DA and BP from before and what about your 60 foot times.
This is a stick car?

JUIC3D

Ya, 6 speed manual.

DA was very similar at +800 feet but the air was different. It was very cool last night but also very damp as evidenced by the layer of dew on the car and the 80% humidity.

My previous best of 10.8@128 was in the same DA but with a little warmer air and a higher barometer.

Dave-T

How did you do last night. The dampness and high humidity is a killer. I have raced at E-Town on nights when the DA was going down significantly but I was slowing due to the high humidity and dampness.

JUIC3D

Last night was bad. The best I could get was a 10.9@126 on a 1.6 60'. I was trying out my new MT Drag radials for the first time and I thought for sure I'd see a new personal best but that wasn't the case.

BLOWNALKY01

Justin,

It's been my experience that an 11-12 sec car would lose .1-.2 and 2 or 3 mph in those headwind conditions. The caveat being that my experiences in these circumstances were never in anything as aerodynamic as a C5. Additionally, this experience also would have been in automatic equipped cars. I would think that your setup would lose a little less than this.

Jack.

P.S. I am only addressing the possible headwind ramifications here.

JUIC3D

Thanks for chiming in Jack.

I need to go back and review my data logs and see what exactly was going on with shift points, launch rpm, etc, but I was too tired and frustrated and just went to bed.

So you're saying the better aero of the C6 would lend itself to reduced impact from a moderate headwind like that? The American flag that is flown next to the staging lanes was at full flap all night long and I was constantly checking to see if the winds would shift for just a second so I could make a pass but it never changed.

BLOWNALKY01

Sorry about that Justin. I've been following your posts for a little while now but somehow I had it in my head that you had a C5. And yes, that has been my experience. The sleeker the design, the less affected by wind.

Jack.

JUIC3D

Good stuff Jack. Thanks for the responses. It wasn't to terribly windy last night but it was definitely a steady 10-12mph in the wrong direction.

BLOWNALKY01

Drag racing can deffinately make you scratch your head sometimes, can't it? The answer is there somewhere, it's just not always easy to find. So many variables, and fleeting weather variables are no help.

Jack.

LS1LT1

I have found headwinds to be sort of a double edged sword with a C5 or C6. It will almost always effect trap speeds, as much as 2mph depending on how strong the gusts are and the car's power level.
But on the upside it's also forcing a little more (cooler?) air into the air filter/motor as it goes down the track as well which could give one at least a small burst of power increase as well.
Given the choice I'd take a dead calm day/night (or a tail wind of course ) but a little headwind is not going to totally destroy a pass.
I can clearly see a 10-12mph headwind taking a 10.8@127mph car down to a 10.9@126mph so your car seems to be right in line and still runnin' good.

JUIC3D

Thanks for the encouragement

I would assume I'm not alone in the feeling/thought/frustration that accompanies a night when the car doesn't perform as you expect it to.

I just want to know and understand how all the variables work together to give a final result and this forum never ceases with the teaching. I thank you all for that.

ajrothm

+1

My old vette EASILY looses 2mph in a 10mph head wind..... I drag race sportbikes as well and I easily lose 1-2 on them as well.....One of which traps 168 ish....

Wind is a killer.....

On the other hand, high humidity I have yet to see a big difference on my cars/bikes or even the DA.... We have had -500 DA and it was so foggy at the end of the track you couldn't see the shut down area... You KNOW it HAS to hurt performance but....I have yet to see it on the slip.... Yet if the baro pressure starts dropping, the DA will drop fast and I can lose 1 mph from the beginning of the night til the end of the night...

Weird stuff goes on in drag racing for sure...

pit-man

I'm in north Florida and I see the same loss on days that seem similar. I bet the humidity was higher that day + the head wind.

Pitt

JUIC3D

Here is the DA for the 2 days at the times that I ran.

The baro and humidity are noticeably different.

pit-man

Wow...78% humidity is terrible (and 68% sux). You need to run that thing in some 40+ degree air and 40's for the humidity.

I had to look at those again...man that is lousy weater. I caught a good Canadian blast and had roughly 48/48 and a Barometer reading of 30.4

JUIC3D

I can only dream of conditions like that.