Good Luck to the Z Racers at the Solo Nationals!

[fp280z]

My first run on Thursday:

http://www.vimeo.com/1803106

As I mentioned in the comments, it was all downhill from there. My big mistake on this run was braking way too much at the end of the chute going towards the final left hander and finish. I fixed that on subsequent runs but I never got the slaloms right again after this run. As it turned out, all of my Thursday runs were within a half a second but they went in the wrong direction (each one slower).

I've got a video from Friday also but I've got to trim it down since I forgot to turn the camera off. That was the run where the car broke.

-Rick

[jmortensen]

One other minor thing for anyone thinking of adding a spoiler. I pushed through a rule change that allows the spoiler to over hang the body at the rear of the car. That becomes effective for 2009. I didn't fully read the rule and put my spoiler on the rear of the hatch and then realized I had to add a "bumper" to make it legal... The bumper was styrofoam and duct tape and will be dropped in the trash very soon! Picture with the spoiler and styrobumper attached...

NICE WORK!!! I had been figuring on having to have the spoiler mounted way up on the hatch to prevent it from extending past the body of the car!

[tube80z]

Well we got that ole P car and Evo this year. However the Evo did get me on Friday and I drove my but off. So, my Z will go through some changes in the coming year. Lower, spoilers and what ever I can bend the rules, I mean follow the rule book. Andy Craig, glad to see you hanging out there.

I'm assuming you've seen some of the discussion going on over at HybridZ. Take a look at some of the low friction swaybar mounts and modified rear control arms. Locally those have made enough of a difference people can feel it.

In back to back testing we found the rear spoiler was worth .5 of a second on a 47/48 second reference course we use. The speeds may be a little higher than some autox events and that may skew the results some. But there is some time to be found in aero for these cars even at autox speeds.

Great to see you guys doing so well in the Zs.

Cary

[gira]

Unbelievable. Mucho congrats to John, Andrew and Tom for keeping these old cars going so fast. I am hoping you haven't taken all the Z Karma I am going to need to beat the damn WANKELS at the Runoffs in a couple weeks. I am also glad that in SOLO, the SCCA hasn't allowed Mazda to pay their way in and dominate everyone in some of these classes. Our runoffs engine is finished today and it makes more torque than last year. We'll try some new gearing and we're going to be lighter this year. I think we have a good chance to win and a great chance to podium.

Way to go Z racers!

Greg Ira

05, 08 SE Div National Champion E Production

[Pablo]

Greg good luck at the Runoffs. Just got home from Daytona today, great time considering. Found the tire wall on turn 7 overtaking a car on cold tires {don't this again} not bad at all kept on going, turned a 26.3 on Sat. then on Sunday blew the old clutch second lap of the morning race was confident was going to able to get a 25 or high 24. the suspension is definute giving me more confidence. See you guys at Daytona in May GOOD LUCK

Edited September 28, 2008 by Pablo

[JTZ23]

Plenty of Z Karma to be had, Good luck Greg, give em hell!!

JT

[tholt29]

Yesterday I conducted a highly scientific test to measure the downforce of the 10 inch spoiler at roughly 60 mph...

I duct taped a digital cornerweight scale under the hatch and propped the hatch open by about 1/4". Zeroed the setup and took a couple of passes across the site... The final result... an incredible 24 lbs of downforce at the rear of the hatch... The scale did have a pretty slow response time but it did appear to level out at that range.

I'll have to do a little math to figure our what that would be at the wheels, but I suspect it will remain unimpressive. FWIW, it still looks mean and was enough to scare John into believing he needs one!

Tom

[jmortensen]

I think opening the hatch even 1/4" is going to throw those numbers off quite a bit.

For reference: http://forums.hybridz.org/showthread.php?t=121877

Granted these tests were done at 80 and extrapolated up to 100 mph, but a 5.25" rear spoiler generated ~105 lbs downforce at 100 mph. (50 lbs downforce and removed 55 lbs lift). Unfortunately you have to look at aerodynamics as a package, and that car also had a chin spoiler so that will affect the total aero balance as well as the front or rear downforce numbers taken individually.

[Carl Beck]

That would be 24 lbs of downforce PLUS the weight of the hatch that you Zero'ed out.

Think about it... the downforce measured would stay at 0 until it was greater than the original weight of the hatch the corner measure was holding up... since the corner measure was sitting inside the car...

FWIW,

Carl

[tholt29]

I don't know that I agree with that logic Carl...

If the hatch weighs 20 lbs and I zero'd the scale with that weight resting on it, every additional pound of aero downforce would be displayed on the readout. It would not take 21 lbs of downforce to show up as 1 lb...

Tom

[fp280z]

Hmm. Since the hatch was not latched I could also see some side effects of the airflow through the windows of the car pushing the hatch up. This would skew your numbers down, no?

-Rick

[tholt29]

I did tape the hatch closed so that it would not lift, but even if the hatch were latched the airflow inside the cabin is effectively the same and any internal lift would still be there so the net downforce is still 24 lbs.

I still think the biggest flaw with my crude test was the slow response of the scales. It's just a single datapoint and if anyone ever tries to do another round of tunnel testing, I'll be glad to send my spoiler for evaluation. I would love to see some better test data on it. For now... this is the best I can do.

Tom