AMG 17GT

Great point. Emeric thought so as well. Car did seem anemic at end of run.

I forgot to try the HOLD, switch to manual and shift early method. And I didn't knock down the spoiler. With a little more traction I thing 3 more mph is possible sea level.

jrcart

Nice runs! I was almost spot on when I said you would go 150+/- mph in the 1/2. I believe I also stated the you will usually pick up 20mph or so over your 1/4 mile trap speed...but what do I know

AMG 17GT

Yes JR you were correct, but you said 20-25 mph over and I wanted the latter range

Kreuzfeuer

It's definitely a thing. In general, your half-mile MPH should be ~25 mph more than your quarter-mile trap speed. That "second quarter mile" which makes up the full half goes by very quickly. But if the DA sucks (and it always does at Clayton), then that number could be more like ~20... especially if the track you normally race has a DA of around 600.

That's why MIR is such a fast track. Negative DA is not uncommon in early/late year, so the lower the DA, the more power you make.

And it seems counter-intuitive, but a little spin in the half-mile actually boosts your overall MPH. When I did my runs in 2013, the two fastest MPH readings were from my two worst launches. If I nailed the launch, the speed was one or two MPH slower.

Door mirrors, if they can be folded in, will add ~2 mph to the overall figure. If they can be removed altogether, bump that up to ~3 mph.

The right lane at Clayton is the fastest one, as it doesn't have that unsettling "dip" at the 2,000 foot mark.

Little things add up.

AMG 17GT

Yes that left lane had some water.

Completely missed the mirror folding. Between that and spoiler that could have got me where I wanted. There was a lot of wind noise. Good points. Shiite!

Will be going in September if your around.

Kreuzfeuer

Absolutely!! Although, when the spoiler is doing its work, it keeps the shiny side up...

But if the car is still stable at ~150 w/o the spoiler deployed, then yes -- that would definitely add a few MPH. There was an Ultima GTR running in 2013, he had a HUGE park bench spoiler on the back. He removed it and gained like 7 mph (!!!), but had a pucker moment when he applied the brakes at the end. There's always a trade-off

I'll try my best to make it down there that weekend, even though I'll most likely be spectating. It's absolutely the best venue on the WGF calendar for spectators. Would love to see your car in action

jrcart

Some duct tape over your upper grill opening and tucking your mirrors in and you would have picked up at least 3mph on the back end. I've run so many of these 1/2 mile and 1 mile events I've got all sorts of little things I've figured out. Since these are not timed events you actually want some wheelspin on the front end, wheelspin(to a degree) will result in a higher trap speed on the back end. Still nice runs and right where you should be. It's fun running in a safe controlled environment, just frustrating when spend more time waiting in staging lines than on the track. I attended the first No Fly Zone Half Mile event in California a few years ago, there was only about 50 cars, it was great, I had my CLK BS and C63 BS there a buddy was driving the C63 and I was piloting the CLK, we are able to make 15-18 passes in each car, it was a great time, lots of head to head match-ups lots of run time.

AMG 17GT

****

I'm getting 156 then in September. JB C 63s err John, that's your number.

JB C63S

Challenge accepted. Elevation 163' for me. And I wont forget the spoiler.

Kreuzfeuer

Get your act together and you'll easily nail 158

jrcart

20-25 mph pick up on the back end of the 1/2 is the range you will see for a car with this type of hp. A head wind or cross wind can cost you 3-5mph. As you mentioned DA plays an obvious roll as well but that is minimal in a forced induction powered vehicle. I've run a dozen or more of these airstrip events and I have seen my mph fluctuate from a Saturday to a Sunday by 5mph with no changes to the car. I would not be alarmed that he only saw a 20mph pick up, that is normal and well within the range I would expect.

Kreuzfeuer

Good points, as you said there are many variables that can come into play. It's not as simple as DA -- it's more like DA, weight, coefficient of drag, headwind/tailwind, tape versus no tape, etc.

I'm still learning, hoping to hit a few of the WGF events in 2018 to build a data bank comparing same car in multiple environments. My car will be naturally aspirated so the delta should be pretty wide depending on DA.

Unrelated to speed, but related to WGF -- How did you like the vendor situation at Clayton this year, AMG 17GT? I heard they clamped down on food being brought in, but supposedly they brought in several food trucks.

AMG 17GT

Learning here as well.

There were food trucks and an open grill. Hotdogs hamburger chicken etc. Let's just say I'm bringing my own next time

Kreuzfeuer

Eeeesh, not good. I think their crackdown on coolers was due to waste... but who knows. At the end of the day, it IS a residential private airstrip, and the general public doesn't grasp the concept of being respectful.

If I don't eat that day, is that 1 mph?

jrcart

another little secret is to air up on your tire psi, especially up front. Since the tires will be cold when you make your run you need to air them up to the high end of the range or even above recommended when cold. Rears can get some heat into them if they allow a burnout, but I have been at a few airstrip events that do not allow burnouts.

Kreuzfeuer

That's a no-brainer that I have never once considered... but it makes perfect sense.

Like a dummy, I reduced the PSI in the rear tires to get a better launch (I was in quarter-mile mindset).

Never touched the fronts, so they were sitting at ~32 psi (normal street pressures).

I will definitely remember that for the next attempt.

jrcart

Air them up, less contact patch = less rolling resistance.

Kreuzfeuer

Absolutely. I'm still pissed that I didn't even consider that in two years of attending the event.

AMG 17GT

As I was preparing for 1/2 mile, I didn't want to go low on oil and found that a quart fits under driver rear panel under tire kit ....

emericr

Thanks for all the great tips.
I am not aware of how to not make the spoiler go up. Is that possible?
I don't think I would want to try to manually make it go down while I am hauling down the strip lol

AMG 17GT

Ha. It's just a button that lights up in roof panel. Press and done. And.......... its 1 mph more man!

jrcart

If anything you want the rear spoiler down, downforce = drag. I believe a fuse can be pulled but I am not positive as my Ed 1 had the fixed rear wing.

emericr

I know it's a button on roof panel and I have played with it to make the spoiler stay up but I am not aware of an option to keep it down.

AMG 17GT

Yes so that's what I kept forgetting. So you have to program yourself like a pilot on these runs. Besides pulling fuses, just program yourself to hit red spoiler button after first gear runs when it goes up and it will go down that's all.

emericr

That's what I thought it meant and I am not sure I want to be taking one hand off and my eyes of the runway while I am at full throttle above 75mph to hit and hold the button for 2 seconds to get the spoiler down...
I would rather be 1mph slower but less risk of an accident. Catch my drift