Today's Test-n-Tune session: 1/4-mile

[RebekahsZ]

Beautiful day today. Trailered down to Alabama International Dragway for my first taste of 1/4-mile with the LS2. Car ran great. Videos and time slips added tomorrow. My goal with this car has been 7.0 at about 100mph in the 1/8th and 11.0 at about 125mph in the quarter. I have been unhappy with the 3.90 diff (26" tires) in the 1/8th, but my drag racing calculator suggests that the 3.90 should be great in the 1/4-mile. The calculator was right! I'm going thru the traps in 4th gear just as the shift light is illuminating, but before hitting the rev limiter. A few passes with the shift light set at 6200 showed me that I'm too darn slow to stay off the rev-limiter, so I decreased my shift light to illuminate at 6000rpm: bumping the rev limiter stopped. Also gradually increased 2-step from 2500 to 3000 and finally to 3500. Car hooked fine at 20psi in the tires, but as I increased the 2-step rpm, I lowered the air pressure to 16psi to soften the sidewall and allow more twist. No handling problems today, although the slow down ara of the strip was very bumpy. 9 passes today - no carnage so far. Met my goal of 125 on the first run of the day, but the 7.0 1/8th time continues to elude me.

 

Best run of the day: The last run of the day - I quit on a high note!

RT: 0.014 (perfect tree at this track is 0.000 instead of the usual 0.500)

60': 1.520

300': 4.607

1/8: 7.141 @ 97.53mph

1/4" 11.055 @ 126.28mph

 

Motor will remain totally stock - I was the slowest car at the track today, but I was also the only one that didn't break. Would love to have some different ratios in the tranny - 2nd gear is here and gone so quickly!

IMG_0914.MOV

Edited November 11, 2012 by RebekahsZ

[Snailed]

Very nice 60ft. Do you drive this on the street too?

[RebekahsZ]

Hell yeah! Thanks for the kudos. I'm going out when I log off to swap the slicks and skinnies for Khumo street tires on RBRs. Hoping to work in it some today with my 15 year-old daughter who just got her learners driving permit. I'm putting my truck in the shop this week to figure out why the heater isn't getting hot, so I'll be DD-ing the Z all this week. A few weeks ago I drove 3 hours each way to Birmingham in the Z-car and drove back in a driving rain. These motors are so sweet - not really all that loud just on the headers if you keep the rpms and load down. I need some door bars if I wanna be NHRA legal, but I real dread how that will kill my desire to drive it to work, dinging my shoes eveytime I step over the bar...

Edited November 11, 2012 by RebekahsZ

[Snailed]

Ah that is very cool. 126mph street cars are fun Those motors really are pretty civilized if you don't hammer on them. Nice sounding when they are cracked open too. Anyway, keep wearing out tires with that thing! It's good inspiration for those of us who are wearing out jackstands.

[RebekahsZ]

2-step rocks. Car was fairly consistent for a manual trans. I am not immune to red-lighting. Timing system is based on a 0.000 for perfect reaction time.

 

Run RT 60' 330' 1/8-mile/mph 1/4-mile/mph

1 .502 1.586 4.748 7.324/95.12 11.304/125.24

2 .041 1.584 4.683 7.207/96.95 11.119/126.31

3 -.004 redlite 1.605 4.737 7.275/96.74 11.225/125.68

Stopped and got a cheeseburger

4 -.136 redlite 1.619 4.738 7.293/94.92 11.284/124.55

5 .076 1.627 4.762 7.300/98.73 11.271/125.27

6 .155 1.582 4.703 7.241/97.74 11.170/125.96

Stopped and watched for a while

7 .054 1.572 4.758 7.348/96.07 11.321/125.05

Increased 2-step from 2500 to 3000

8 -.026 redlite 1.610 4.701 7.235/97.03 11.159/126.06

Increased 2-step from 3000 to 3500 and dropped air pressure from 20 to 16

9 .014 1.520 4.607 7.141/97.53 11.055/126.28

Put it on the trailer and headed for home

Edited November 11, 2012 by RebekahsZ

[SUNNY Z]

Killin it Keith!

 

Whats the car weigh?

 

Glad to see I'm not the only one who came up short of 10's this year! haha

Edited November 12, 2012 by SUNNY Z

[RebekahsZ]

I weighed it about 15 years ago and it weighed 2160 without me in it with about 1/2 tank of gas. Haven't gotten it on any scales since then. I weighed 40 pounds less back then, as well! I think I'm gonna add some door bars to the roll bar to try to get closer to being NHRA legal - not looking forward anytime soon to adding a SFI rated bellhousing, since I've been all over the clutch lately - it is like a cancer I can't get away from! Both of those will add some weight. I think for this winter I'm gonna just try to get it autocross-ready and more reliable/easier to work on. Maybe next year I'll add a nitrous kit to be used in high gear for bragging rights only - I think it will just add variability and make bracket racing impossible. I bet that will get me into the 10s., but goes against my desire for trouble-free operation. I have no idea of what kind of "tune" my car has. How much performance can a computer "tune" be worth? I don't want to make anymore speed in the first 60' - I want to keep the axle system intact. Any more speed I make, I want to make after my last shift, so that's 3rd gear in the 1/8th and 4rth in the 1/4. Would you consider 10.999 "in the 10s?" I'm closer to the 10s in the 1/4 than I am to the 6s in the 1/8th.

[SUNNY Z]

Good grief - and people say MY car is a go-kart. Yours is like 800# lighter! which makes the numbers add up now. Maybe I'll put mine on a diet this winter..... if only i knew where to trim the fat.

[RebekahsZ]

I think this biggest diet pill to swallow is you gotta start light with a 240z instead of a 280z. Its been a long time since I weighed it - that's probably not accurate anymore. I can't remember if I had the roll bar in then or not, my drag wheels and tires are a lot lighter than what I had on it then. Don't remember which seats I had in it or what state of undress the interior was in (I had some boat anchor seats in it once, but they sure were comfortable; I now have 14-pound seats in it). I've got a carbon hood right now that is about as heavy as a piece of typing paper. Bumpers and grill are gone, windshield wiper motor is gone, but is coming back, no undercoating, only paint on the floors, minimal stereo system, no real exhaust right now either. I don't know if coilovers save any weight, 1" swaybar up front, none in back. Now R200 instead of R180, don't know how the CV axles weigh out. Still have my stock spare tire installed since it is in the back of the car, battery is in back, too. Your car is nice enough to take a girl in a date - they would run from mine. Your car can go a lot faster than mine, you just gotta get more chances. You can't get any practice if you break an axle every time you try.

[RebekahsZ]

Got some videos cut down into small enough files to post.

Burnout.wmv

Steele Video1.wmv

Steele Video4.wmv

Steele Video5.wmv

IMG_0914.MOV

[RebekahsZ]

Check this photo of my tire wear pattern. The inside 3 inches look twisted and by the wear markers I am getting lots more wear on the inside of the tire. This is with 0.4-degrees POSITIVE static camber. From the videos above, you can see lots of rear suspension working. One of this winter's projects is to find some kind of rubber wedges to jam into the coil springs to further eliminate squat.

[wfritts911]

Your car is nice enough to take a girl in a date - they would run from mine.

 

If they run from yours...I'm in trouble lol. It does attract every redneck within a 1/4 mile radius though.

 

Its too bad I'm on Linux and don't have any software to play those videos. But you were so close to 10s. I think if you could launch a little harder you could get it, one really hot burnout and a good launch and shifting. Definitely looks like you have some serious squat/camber going on from that picture. Were you spinning any with the 2 step at 3500? I bet you could have just turned it up and either ran 10s or broke axles like the rest of us lol.

 

And I am jealous of your weight, the guy I bought my car from said he weighed it in a 24xx when it still had the L28 turbo in it. I figure I have lost a bit of weight from that point, but not much. Running 11 flat on a stock LS2 is awesome. Unfortunately I'm not sure I will be doing anything but adding more weight in the future.

 

Is this going to be your last time running this year or are you gonna try to squeeze in another visit or two before the season comes to a hault?

 

-Will

[240z72]

Awsome videos Keith! Love the cockpit view. I want a two step now hahahah!

[RebekahsZ]

I'm calling it quits for the season. The only place that is reliably open is the 600' track. All the others, you get ready, wrench all week and then they are closed due to cold or rain, or just the threat of rain. California dreamin'. Did you know there are 3 dragstrips in Hawaii? Anyway, as soon as my truck gets the heat fixed I'll be starting on converting an open 3.54 to a CLSD. Then exhaust. Then heat and wipers, etc, etc. Gotta quiet this thing down so I can do some autocrossing in the spring - hoping for a trip for that back to Little Rock, so we'll have to buddy-up. SCCA Solo II folks are serious about not losing their parking lots, so they don't tolerate noisy cars. It is amazing how much work it takes for each 0.10 in the 1/8th or 1/4-mile. Simply beating on the car just results in a car that is beaten up. When I start dragging regularly, I'll probably move the 2-step down rather than up. It sucks to go home broken and it sucks to delay racing to clean up oil - track is crappy all night and everybody hates you for bringing your wimpy car to the track instead of putting in a Powerglide and a 9-inch before flirting with the big boys. My daughter loves to quote one good-ole-boy who commented on my car at the track: "That car is bayed ayss!"

Edited November 14, 2012 by RebekahsZ

[Snailed]

Check this photo of my tire wear pattern. The inside 3 inches look twisted and by the wear markers I am getting lots more wear on the inside of the tire. This is with 0.4-degrees POSITIVE static camber. From the videos above, you can see lots of rear suspension working. One of this winter's projects is to find some kind of rubber wedges to jam into the coil springs to further eliminate squat.

 

What is the toe like in the rear? I wonder if it's changing a lot under acceleration. Too bad you can't easily dial in some anti squat...

[wfritts911]

I understand on not wanting to break, I definitely agree that breaking is no fun(Been there a lot lol), I just can't seem to stop pushing the car to try and get those lower times. Guess thats why I finally said forget the IRS after reading everyone elses issues. The only way to go fast reliably is a solid axle, and I'm tired of always worrying about what is going to break next. Dropping a tenth is a lot easier when you are running 13s instead of almost 10s.

 

Ya I'm glad you didn't come up to autocross this year, my exhaust would not have flown with an actual SCCA event. The one they do up in Rogers, AR no one cares, everyone thinks its awesome lol. It will be quiet before next season. I'll have to see how my solid axle setup can do compared to a IRS LSx Z car.

 

Snailed, I don't think Anti-squat is definied in the Z car dictionary.

 

-Will

[Zfan1]

Sweet times, my 240Z with a first gen 385 runs high 10's to low 11's. I am pulling the motor and swapping in an L76 6 liter with LS3 heads and intake, DOD Delete and a cam, size yet to be determined. Transmission will be a 4L80E with 3600-3800 9.5" converter. Hoping for mid 10's on motor and mid 9's on the spray.

 

Your Z is damn light, mine weight 2850 with me in it!

[RebekahsZ]

I really need to weigh it again - those numbers are from memory almost 20 years ago, so they should be viewed with caution. I think SUNNY Z is just trying to justify why with a stock motor I'm ALMOST as fast as he is! I'm sure he'll clean my clock soundly once he gets some driveline reliability. He's a better driver with a better car.

 

I need a mentor to spoon feed me on how to set up a nitrous system for use only when racing for bragging rights. I still plan to try to bracket race on motor only with a 2500 launch rpm on the 2-step. Anybody want to talk me thru it and wade thru some stupid questions? If I'm thinking about it I should do it before taking the car for a tune in the spring.

[SUNNY Z]

I think SUNNY Z is just trying to justify why with a stock motor I'm ALMOST as fast as he is! I'm sure he'll clean my clock soundly once he gets some driveline reliability. He's a better driver with a better car.

 

I need a mentor to spoon feed me on how to set up a nitrous system for use only when racing for bragging rights.....

 

You got that right! I signed up for some dyno time - sometime in the near future, TBA, so we'll see what it REALLY makes.

 

Better car/ driver.... psh

 

Start Here for nitrous info: http://ls1tech.com/forums/nitrous-oxide/1242567-spark-plug-info-jetting-faqs-all-nitrous-info-read-me.html

[RebekahsZ]

Driving car to Arkansas just crossed into Mississippi where the roads are dippy.