A little fun at Thunderhill...
 

This would be a bad link to click on if you're on dial-up... 85MB

http://www.kamikazeracing.org/dl/ZTr...sion-1mbps.wmv

Looks like a lot of fun!

One of these days I'll get to do stuff like that.

Rod.

Man that looks like it was fun, what was your average and top speeds at that track? I see you had some kind of mesuring device on your windshield, any chance it had a G meter in it? That engine sounds pretty tight and smooth too. Kudo's to you man!

Right on L-dub, that was a treat to watch. Man I wish I could take my Z to a track, and have some fun. Maybe sometime, I will take him to Firebird raceway in Phoenix. And your Z does sound pretty mean. You have the stock 4-speed in that Z? I am guessing that is your 240z in the video. Going by the interior, gauges and such. All in all man good stuff.

Yup, it was my 240z with a set of 15" ZXT wheels running Hoosier R3S04 DOT radials.

I got up to 112 mph on the front straight before the braking zone and on corners pulled over 1.2 Lateral G's according to my G-Tech Pro RR.

I could have gone faster on the straights but I was running stock brakes with AutoZone brake pads. The only 'upgrade' I had was DOT 4 synthetic brake fluid and the brakes were virtually non-existent by turn 5.

The vast majority of my braking was done with the engine and uncharastically good heel/toe work.

It didn't help me when a friend of mine that drives like a freakin' lunatic came up behind me in his 350Z, shook my concentration and my heel slipped off the gas pedal making me hit 2nd gear with about 1200 rpm's doin' nearly 50 mph.

The rear tires slowed up enough that I lost traction and spun off the track in turn 5 denting a wheel...

Unfortunately? I didn't have the camera hooked up for that run. It was quite a spectacular spin into the dirt with dust flying up in the air right in front of the grand stand!

I do try to entertain... :unibrow:

very nice driving!

Thanks KTM! It does help that I used to do a little SCCA Club Racing back in the late 80's/early 90's.

I was taking my apexes a little early, not uncommon for someone who hasn't done any track work in awhile, but my heel/toe work was excellent once the tires got up to their optimum operating temperature and I settled down into a good rythm. I was pleasantly surprised with several good passes throughout the day.

The stock 240Z motor with stock airbox was running extremely well and hummed along beautifully, even at nearly 7000 rpm. The water temperature only got over 210 deg. twice throughout the whole day during a few times where I was working to hold off a more powerful car.

Yeah I will agree, a verry fine piece of driving man. And your 240 still has the duel carb setup correct? Anyway sometime, I still would like to just take my Z on the track. Man I bet it is an ultimate rush bro'. Sorry to hear you spun out your Z. But anything can happen in a race.

I dont know much about track racing but I would really like to do it someday.. but my options are limited around here. It looked like your keeping right up with those faster cars through the turns. Thats true driving skill.

oh ya.. How acurate is that Gtech????

When properly mounted and setup, the GTech is very accurate. Most people don't follow the instructions when mounting them and their numbers are all over the place. The key is to mount it while the car is on a KNOWN flat surface.

Not as easy to do as you might think.

sounds like a dumb question but how do you know if your car is on a perfectly flat surface.. Obviously you could just look but would that be acurate enough? My friend wanted one for his Golf

Just toss one of these down on the cement...

http://www.spartanphotocenter.com/im...le%20level.jpg

http://contractorstools.com/graphics...ser_dot_lg.jpg

http://img.diytrade.com/cdimg/227789...1119166784.jpg

Bubble level is correct!

Although, I put it on the cowl with me in the car so it compensates for the extra weight in the driver seat vs. the passenger seat.

Most concrete garages are pretty darn close to flat if they were poured by an experienced mason.

In my experience, most driveways are NOT anywhere near flat!

Yes, it still has the original '72 dual SU carbs with leaky throttle shafts and everything!

I didn't have the power in the straights, but I could close the gap on the leaders in my class pretty well in the corners.

Nice, this was this past wensday? The 240 sounded great. Your little gijit was kinda in the way of the camera though. Nice vid though. On a side note-Darrell and i saw some of your friends today on the bay bridge . . .posted it in another thread though :)

Yeah, I didn't realize the GTech was in such a bad spot until I downloaded the video from the camera.

Also, a 'friend' stepped on my panoramic racing mirror so, instead of getting a nice peripherial view from the mirror, you just see the top of my helmet... ;(

Time to order a new racing mirror...

It made it fun with no passenger side mirror. My panoramic mirror had such a good field of vision I didn't need the side mirrors before!

Downloading as we speak. We'll see how it is pretty quick.

Gotta love road racing. Since Miller Motorsports Park opened up less than an hour from Nismo and I, I've been jonesing for some open-track seat-time. Road-coursing has been entertaining to me since I could walk. :D

Here are some shots of me spinning out in turn 5!

http://www.kamikazeracing.org/dl/ZTr...0713-spin1.jpg
http://www.kamikazeracing.org/dl/ZTr...0713-spin2.jpg
http://www.kamikazeracing.org/dl/ZTr...0713-spin3.jpg
http://www.kamikazeracing.org/dl/ZTr...0713-spin4.jpg

Crucial. Is it me or does the ass end of a 240, or most Z's for that matter, come out from under ya real easy? You can almost see the "oh sh*t" look on your face. . .

Yup. And I'm running 205/50/15's on the front and 225/45/15 Hoosier's on the rear and I can still steer that thing with the throttle.

Isn't perfect weight distribution fun? :D

It definitely has good weight distribution, but the rear suspension tends to make them handle like a 70's or early 80's Porsche. Very tail happy.

As I am always quoted saying ...

"Ain't nothing wrong with that!" :D

So I'm assuming the initial trip over the rumblestrip dented your wheel?

very nice! i take it that it was your 72 240? if you ever do that in you 82zxt get so more vids! One day i will be out there racing with ya! Dont have to much fun. lol and if you get some more camber it will help with turning in the corners.

I run 225 width on all four corners in my 280ZX 2+2 (yes, a totally different suspension and size of car) and it seems to have just a bit of understeer. I suppose that's the safest for street driving...

If I add more camber, it'll make the back end even MORE tail happy.

There's no factory camber adjustment on the rear of these cars so the only thing you can do is add more camber to the front... ;(

Believe me, the car is setup as well as possible for the track without going to coil-overs.

Just cut your springs and SLAM it! That'll give you camber.... oooh ya, you'll be cool then. Oh and paint a rising sun on your hood. Gotta have that!

hey i gotta q now that were on the subject. my car pushes really bad at slow speed, bleach can atest to this, hes seen it, i got 255's all around, it handles great at speed, just not slow speed, how can i correct it?

Like, slow speed under acceleration? Or you're just turning around a casual residential corner at 25 mph and the front end pushes out?

under accel, and if i really push it at slowish speeds, like 30-50 kph around a 90 degree turn on the street. i got slightly positive camber, would that not help much at the moment (i havent got around to cutting the springs down yet) and the big sway bars 1/1/8 front and 7/8 rear

Under acceleration, you should get slightly positive camber.

But I'll bet it's that big front sway bar. 1" front and 7/8" rear will help get the rear end around.

On FWD cars, because they have such big understeer problems, they usually go with over-size rear sway bars.

I was running -3.5 deg on the front of my Honda with the stock sway bars. When I went to the over-size SI sway bar on the rear, I pulled over 2 deg. out of the camber and got it down to -1.25 deg with the same corner handling characteristics.

so if i lower the front just a little, it would stay more negative, therfore creating less push, plus i need to correct the back, i think im aboot +2 deg camber

I was thinking about this, because I have noticed the same thing with my car since putting on the massive/sticky/wide tires...

I have a lot of negative camber on the rear too, which doesn't help. The camber on the front is perfect because I have the bump steer spacers in there.

So, we all forgot the easiest and cheapest way to get rid of some of the cars tendancy to push at lower speeds...

Drop the air pressure on the front
Raise the air pressure on the rear

This is soooooooooooooooooo overlooked and can make MASSIVE differences in handling.

Just think of how much NASCAR and CHAMP and FORMULA 1 teams play with different air pressure settings on those cars to achieve the results they want...

I'm gonna play with my air presure a little and I'll let you know the results.

Now granted, this is not a "Cure all" but it's probably something that will make a huge difference. Idealy, you would still want to correct any camber or other alignment issues that you have as well.

Rod.

In addition to Rod's suggestions about tire pressures, etc., I'd consider an alignment. Sounds like a toe problem. That has, at least in my case, been the culprit of low-speed pushing.

Think of it - toe-out improves cornering, and toe-in improves high-speed stability. Therefore, if you've got excessive toe-in, you'd have great high-speed stability and the like, but rather poor low-speed handling. On the opposite side of that dime, if you've got excessive toe-out, your car will handle very responsively at low speeds, and become very squirrely at higher speeds.

The following link describes what I'm thinking flawlessly. http://www.ozebiz.com.au/racetech/theory/align.html

Tire pressure is an excellent short term solution, but you absolutely need to get your alignment setup properly so you can run the correct tire pressures for your tires to maintain proper heat range and tread wear.

Get the car to an alignment shop and have them check the straightness of the body. If your body is tweaked, it'll make it really hard to get the right alignment to begin with.

You can adjust your rear alignment in several ways like cutting coils to lower it and add more negative camber, slotting the shock tower mount bolt holes or slotting the rear control arm's to adjust the position of the mounts to compensate for weird alignment issues.

Worst case, you can have ArizonaZCar.com fab you up a set of custom adjustable control arms... ;)

I've found that going with higher profile tires goes a long way toward low speed grip in these types of situations in which nobody has changed the geometry of the suspension to the point of relocating pick up points.

The hard part is getting used to the wallowy feel of the higher profile tires and the finesse required to make a wallower handle (think 300zx in Improved touring).

Many a 240z can pull 1.0g on the skidpad with some good 225/60s.........no need for crazy low profiles that cause wheels to die through normal driving.

This is why most of the front running IT cars still run 60 series tires......well that and the fact that you cannot change diameter from stock.

how does sloting the top of the REAR shock towers help? it wouldnt really effect anything, on the front this is true, but not the rear, and yeah my car is aligned properly, i had it done with all new componants, and i havent hit anything since i had it done, i really need to get rid of that positive camber in the rear, and maybe try the air thing, but im also interested in permenently fixing this. i also find it interesting that others have this problem and its not just me. i never had this prob when i had 225/60/r14 on it. what size are yours now rod? and could it be because our cars weigh so little, the weight is spread across such a vast distance of tire? less psi on the roads surface?

First, slotting the rear strut mount points can make a HUGE difference by allowing you to adjust camber by "leaning" the top in or out. Rear alignment problems are the least recognized and least understood, and can create WICKED poor handling problems if not corrected.

My tires size now is 245/35/ZR18 ... they are some wide, sticky sonsabitches!

I have A LOT of negative rear camber / \ and because of that, the rear wants to stay PLANTED at slow speeds a lot more than it would with... ZERO l l or Positive \ / camber.

L-Dub is on the right track :)

Rod.

Keep in mind though, that your rear suspension camber is completely independent of the shock ... it's an A-arm mounted to the body, with a spring holding it up. The hub is mounted directly to the A-arm, not the shock. Moving the shock's top mount won't do much on a ZX.

Think about how the A-arm moves throughout it's travel and what controls that travel. It doesn't move straight up and down. It's on an inside pivot point and the outside travels in an arc.

By moving the angle of the 'at rest' position of the shock, in essence the pre-load on the spring, in or out will change the at rest camber of the car and more importantly, the camber under suspension compression as it moves through it's arc of travel.

Yeah!
Damn Skippy!

That's what I was sayin'

Rod.

........;)

Thanks for the video. Nothing like a day at the track, looks to be a fast one too, plenty of flow. There is a video around of a Z32 at that same place.