1/4 mile - the eBay T3/T4 Chinacharger again
 

Last year the car went 12.98@106. Boost was 12-13psi in the midrange then dropped to 10psi. Someone didn't have the ebc set up properly.

This past saturday night:

-2540lbs going down the track
-Almost corded, 2003 build 225/50-15 BFG drag radials, 29psi, BACKWARDS (forgot that they are directional)
-It was humid - altitude density 1975
-MBC
-Tell tale showed a max of 14.9psi, no real datalogging
-Button to run on WG (7-9psi) for the launch
-OTS Koni's: front-full soft, rear-full hard
-before the run the peanut gallery was talking smack about lame and slow Miatae.

1.8905 60'
12.56@113mph

R/T .4339 (this is significant because it was a pro tree)

No in car video but I think there were 3-4 external cams going. I'll post when I get them since it might be the best burnout I've done - in this car.

Nice run.

Wouldn't you want the suspension in the rear softer so that it squats?

dvcn,
I know you run WI, but what are you using for engine management? Are you still on stock internals?

I can't wait to see the video.

Good job.

Ive never been into drag racing, but Ive done quite a bit of work with road racing suspension, so I may be wrong about this, but I think that 'squat' is something that it to be avoided for off-the-line traction.
Im not really sure why though, haha. I know a lot more about traction once the car is moving.

You do want squat for weight transfer and to not shock the tires. The bad part about squat is that it gives us more negative camber. What happened last year (noticed it while watching video shot from the back) is that the car squatted then when it rebounded the tires spun. Could be that boost hit at this point too or a combination of both.

The OTS Koni's are rebound adjustable only. So I wanted them to squat then slowly rebound to keep the weight transfer as long as possible. Kind of like the 90/10 drag shocks except on the other end, backwards and not as good!

I was going to set the camber and toes to zero but I had autox the next day.

Engine management is the ultra lame Wolf 3DV4. It has an internal MAP sensor that is going bad. I've been too lazy to wire up the external GM 3 bar in its place. It's on of the reasons why I held back from turning up the boost and doing more runs.

Yup, same '96 stock motor with 203k miles on it. It does burn some oil but adding in some 15-50 really slows down the consumption.

Fuel and timing are very conservative. I probably wouldn't knock w/o the WI. It is just insurance and to keep the carbon from coming back. I was overly rich on the fuel, 11.2-11.3 almost all the way down the track.

I can't wait to see the video too!

Camera angle 1. They missed the burnout, makes me sad. To be fair, the GSXR-750 was late on the lights, had a bad 60′ and let off around the 1,000′ mark. Still, it was fun and makes for a great video!

I hope the burnout video shows up someday.





Timeslip:
Attachment 203440

They were running a .400 pro tree that night.

nice run man

Squat is bad, when your car squats its because you are transferring torque into your suspension causing it to compress. when the rear lifts it is actually the tires pushing into the ground.

Nice, Lev should bet some tips from you :giggle:

Great run, your 60' time is great and judging by the video, it pulled hard all the way through.

Ryan and I were standing behind Craig's car in the staging area on this run; he did a great job. The burnout was also very cool :bigtu:

Craig's level of performance on his 'low budget' kit is very commendable, and inspirational.

It's not so much that squat is good but that it is going to happen if you have a vehicle with a suspension.

I agree with you but what goes up must come down. After the midpoint of the rebound cycle there will be less force on the tires, reducing the amount of traction. This effect would be worst on an underdamped system (rear shocks set on soft). That's why I was going for overdamped (rear shocks on hard). Just trying to make transients happen slow enough to be insignificant.

and so far..... LUCKY!

The problem with independent rear suspension (IRS) cars in drag racing, is that there is a pause between the time you dump the clutch, and the time the car moves forward. There is a lot of suspension travel in IRS cars, and it takes more time for the car to travel downward (squat). Once the car stops moving downward, than the car will start to move forward. During this downward movement, the clock is ticking away.

Ever notice that straight axle cars have a quicker ETs than IRS cars (assuming they both have the same power to weight ratio and or similar trap speed) Straight axle cars do not loose that time squating.

There are other problems with IRS cars when it comes to drag racing, but they can be improved with the right set up.

that's a great 60ft! i don't see anything wrong with a china charger. i know of and have or have had many cars with them. used in drag,road,drift, and street use. all have lasted many years. the cars that are still around have had them for over 3 years now, and still running strong. we have a crx demo car for our shop on a china charger running 12.1 @113mph on 9 psi. gonna be at SAR soon to see what it does at 15-18 psi! my personal galant vr4 has one too. after my turbonetics turbo's seals went out, i figured, what the hell, if it lasts a year at the price i paid, it was worth it. that was back in 2005! i've run 26psi on race gas and daily drove it @ 18psi on pump.

Agreed that IRS isn't the way to go for drag and that there are a lot of dynamics going on. Straight axle cars do squat too though. Was just trying to make an excuse for running the shocks on stiff instead of soft. If possible, I'll set the camber to zero next time.

(for people who haven't been down the 1/4) I never drop the clutch. It's bad for a lot of reasons. Shocking the driveline is hard on parts and is more likely to spin the tires. After staging I'll let the clutch out until it barely engages to take the slack out of the driveline. Then I'll push the clutch in just a bit. Having the clutch pedal just below the engagement point keeps pedal speed down and reaction times more consistent. On the launch I slip the clutch for about 10'. Reduces the chance of bog, doesn't shock the tires and doesn't hurt the driveline.

If you are trying to get a good ET shallow stage and don't worry about reaction time.

What shop?

A friend is bring out his 550awhp Evo out to SAR next week, might go watch him run. I'm not going to run again until I install the new MAP sensor and can turn up the boost and tune it more aggressively.

it's a car audio shop called competition sound in corpus christi tx. we sell performance parts and accessories also though. it's good for me, i get a deal on any parts i need, plus i get to drive the crx at drag and road racing events, and occasionally, i do a few auto-x too. it's a fun car, it only weighs 1950lbs. and made 238whp @ 9psi. and hopefully close to 300 at 15-18psi. we'll dyno it soon. for road course events 7-9psi is plenty though.

I would agree that setting the rear shocks to a harder setting would be the way to go. Can't prove it though, because my shocks are not adjustable. I have adjusted my front and rear wheels to point as straight as possible and gained considerable mile per hour at the trap. It was the final adjustment to put my normally aspirated car in the 13s. Try it, I think you will be pleased with the results.

Sure straight axle cars squat, but the squating distance and time is shorter than an IRS.

I do have a question. What spring rates do you have on the rear? I always thought that having a higher spring rate would correct the problem of excessive squating.

I didn't think it would do enough to go through the hassle of changing the alignment. What was your toe/camber settings before and after and how much of a difference in traction, ET and mph did it make? Did you just set the toes to zero and the static rear camber as close to zero as possible? I will definitely do it next time.

Spring rate? Having a highly developed SSM car :laugh: I have stock springs in the back with NB top hats. I forgot about those. Part of the reason for previous traction problems may have been from hitting the NA bump stops.

It would have been in the stock location. It may not have been set correctly from factory, because the car was hard to push by hand. I used plumb bobs and a straight edge on the floor. I measured the distance between the front of the wheel and the back of the wheel to the marking on the floor. I adjusted it until the distance was the same (front and back). After the adjustment the car was easier to push so it just took less power to propel it down the track. I do not think it helped or hurt the traction.

The car went from 14.0's at 94.something mph before the adjustment, to a best of 13.89 at 96mph after the adjustment.

It may not help you much if your car is close to zero, but it is worth a try.

I doubt that the NA stops would hurt you much, it never hurt me. I have run a best 60' of 1.71 when the car had nitrous.

Good luck

Im not bashing you shock settings just making sure everyone understands that it should not be your goal to squat at all. It is very difficult to get away from in IRS cars, and set up to drag is about the only thing its good for. If you look at a car with a really good drag set up it will not squat at all. YouTube - capri drag launch check out this link, other than almost flipping over backwards his rear seems to be set up right. in the slow motion you can actually see the rear tires push down into the asphalt as soon as the torque is transfered and the tire actually compresses, not the suspension. Here is another good one right around the 41 sec area. http://www.youtube.com/watch?v=ryDYY...eature=related Just to note both cars are strait axle cars but both are set up fairly well, and show a good launch. even with the entire weight of the car they dont squat.

That car does squat. At 9 seconds into the video notice that the tire disappears into the wheel well, you can only see wheel. When you run 8-12psi on a tall soft sidewall tire, I'll argue that the tire becomes part of the suspension.

Anything that is not solid has to compress/rebound at some point, it's just the nature of things. I'm not saying that it is good or bad. It just happens.

I totally agree that IRS is not the way to go for drag racing. I agree that the stock architecture of the miata suspension is not set up for drag racing. I also agree that squatting and lifting the front/front wheels is energy that is not used to make the car go forward.

I am just reporting what has worked/not worked for me. As with everything, I am just one data point out of thousands (millions).

Your set up is working pretty darn good.

As for the IRS/straight axle issue, I would think that with more people trying different things, one could go real fast with the IRS. Hell, it is what came with the car, might as well maximize the performance.

You also have to look at the type of tires those cars are running in the videos. Not to mention that those are more purpose built cars setup for drag racing. Every Miata owner that I have met runs their car at the strip the same way they run it on the street.

Im not trying to say anything bad about your results or set up. I dont even have any for my miata. I was just stating what is and is not correct for a launch so others dont get confused or go the wrong way with how they try to get there car to launch.

This is the statement that caused my concern, not your set up or time.

My comment was concerned with weight transfer.

ahem hey guys we are kind of shitting on this thread of kickassness maybe if Joe or someone with mod powers is watching we can shift the drag racing technique discusion to a new thread. Seriusly lol we are quiviling over symantics here.

I'm done, I'm not on this forum to discuss drag racing. I was just trying to help

Yes, lets stop the flow of interesting information. I'm not into drag racing (obviously) and am quite happy to have my assumptions challenged, hence why I'm reading/posting. Why would a mod need to moderate this?

its not about being against the flow of info but we are detracting from the original post. Moving the discusion to another thread would clean things up imo.

dvcn
when you say corded do you mean the tires are shot? The mile per hour you have posted is enough to put you in the 11's. That is damn good. How tall is that tire, and what gear ratio are you running? What is your shift and max rpm? Have you ever considered running slicks?

The tires have a build date of 2003. They are pretty much useless unless you REALLY heat them up(Still waiting for the line lock video so you can see my definition of heating tires up). The tires are bald with slight evidence of tread on the outside 3/4" of the tire. They are 225/50-15 BFG old style drag radials. I'm running a 4.10 Torsen out of a 96 and a 6sp(thanks Ben!). The rev limiter is set at 7300, the shift light at 7000. I was watching the wideband so hard that I hit the rev limiter twice on the run which didn't really help the ET.


I would run fresh drag radials before slicks, they stick amazingly good. I'm not making nearly enough power to require real slicks. I had an NA 1985 RX-7 that ran a 13.53 on 205/60-14 Nankangs. With Mickey Thompson ET Drags, launching on the rev limter at 9300rpms I ran a 13.7. It's embarrassing to bog. There are people running in the 8's with drag radials so they are sufficient for most street cars. Besides, it's fun to drive 90 miles round trip to the track and get 26mpg+.

ApexOnYou is the man. He ran that 11.99 on street tires. Amazing. Check out his videos and what he has done. Breaking into the 11's is serious.

I have been running the Nitto drag radials, and have gone pretty fast with them. I hate the tire hop I get with them however. I can literally feel the car shaking apart. Do you experience that problem? Maybe I should try a different brand.

You are producing plenty of power and torque to use slicks.

I run slicks on my car now, and it is smooth as silk when I launch. My car is not nearly as fast as yours, but I get great 60' times. I have had some bog, but I can correct it by adding air preasure in small increments until the car spins just enough to keep it in the power band. I get the best 60' times with a tiny bit of spin. I have always gone faster on slicks than on drag radials. Practice and patients is what it takes regardless of what you use, but slicks seems to be the user freindly of the choices, as long as the tire is sized correctly. Small cars need small tires. I consider using drag radials as advanced drag racing. It is more of a challenge to get them to work properly.

The best part of drag racing is the kick in the ass feeling you get at the launch with a tire that works. Try it sometime.

Another video, same run but different angle. The two miatae that line up before me are SSM autox friends. Left lane is a bone stock MSM and the right lane is an NB w/ coldside blower (and probably a burnt valve, it's way down on power).

The burnout wasn't nearly as good as I thought it was. I'll do better next time.




Video was shot by a friend who autox's his 500whp sleeper S2k. It was his bachelor party at the track.

Awesome vid. I think a lot of people don't realize how hard it is to ride a bike fast. Still an awesome win.

Great video. Not a bad burnout either.

I am suprised that they allow bikes to run against cars at your track. They are not allowed at the tracks I have been to here in Florida. I guess it is a saftey issue.

There is nothing better than beating a motorcycle. It is usually pretty hard to out run one.

What are you talking about?! It was a cool burnout.

Speaking of which, what is the etiquette with the burnout water box at SAR? They made me drive around it. But then can I back up to get the rear tires wet?

Gobs of them are there every time I have been, everything from stock UJMs to slammed turbo busas. In fact I have run my 1997 ZX-9R there before, stock configuration. Best I could do was an 11.01.

It is SUPER hard to launch a bike. People look at the 1/4 mile times in the magazines and think that they can ride like a pro and hit the same numbers. A long time ago I think the magazines used Peewee Gleason to do the track tests. Kind of like hopping into Scott Pruett's car and expecting to turn the same lap times.

I've only launched bikes on the street. It resulted in wheelies or wheelspin and every single time it was slow and ugly.

If you look at the timeslip, the guy would have passed me at the stripe if he stayed in it. I think by the 1,000' mark he was just demoralized and let off. There is no way my car can stand up to a GSXR-750 unless an idiot is riding it.

I'll post up the burnout I did in my 1st gen RX-7 during a burnout contest, it'll make this burnout look like a 3rd gear chirp!

I put up some info on the local autox site as a primer. (you already know this, this is for any first timers) An excerpt:
I drive around the water, back up into the water box, spin the tires 1-2 revolutions just to get them wet then roll forward. I try not to splash water up into the wheel well. (in the video, note that they put water in the waterbox only AFTER I did my burnout) When they give the burnout signal I set the line lock and do a 2nd gear burnout. If I'm being an ass I'll shift to 3rd before releasing the line lock to see how long I can carry it out then slam on the brakes right before the staging lights.

My drag racing bro-in-law felt it necessary to remind me that burnouts are not for show. I agreed and told him that they are for fun!

I have been to a track where they discourage radial tire (not drag radial) cars to go in the water box. I have no idea why.

If I recall, most cars go around and back in. I guess it is to keep the front tires dry.

Good burn outs are absolutely for show, and part of drag racing awsomeness.

word launching a bike is hard, best my lil vf500c ever pulled was a 7.8 1/8th mile felt like i was on the verge of pulling wheel the whole run twas awesome. The burn out was pretty decent man GJ.

Absolutely it is hard, unless maybe you have a 20 foot swingarm on a slammed bike. On a normal sport bike, it is a fine line between bogging the launch, getting it just right (front tire just off the pavement) or back-flipping.

The back-flips do happen. I have seen one in person, and it is not pretty. The rider broke his foot.

a trap speed of 106 is not good for 11's....

You misread the thread. He went 113 on that pass. He went 106 from a previous setup. Go back and check it out.

I'm thread jacking. It's ok right? Here are some half decent burnouts from the car I had prior to the miata.


The last segment is a burnout contest that I came in 2nd place. Maybe it's because I ground 2nd gear, who knows.

Can you thread jack you own thread?!

Pretty impressive burnouts. Get checked out for cancer! ::laugh:

That's awesome Craig....What do you have under the hood of that RX7?

Street port (mild compared to what the PR folks do) four port 13B, Holley 650DP (modified....), Racing Beat manifold, custom manifold spacer to convert to open plenum, full RB exhaust, RB aluminum flywheel, clutch and pp. Dual MSD 6AL's, direct fire/wasted spark to the leading spark plugs, trailing fired through distributor. 13.54@102mph

Shortblock cost $350 in parts to build. 1984 rotors and eccentric shaft, 1982ish side housings, 1976-78(?) rotor housings. Five apex seals at the minimum spec, one well below.

The motor was built just to run long enough to be the guinea pig for the future turbo setup. After minimal NA tuning it ran pretty well considering the quality of the parts. After severe abuse and shifting (and sometimes launching) at 9300rpms (made great power after 9500 but just felt bad spinning it that high with less than stock parts) one of the apex seals cracked. The turbo setup was never installed.

Could have rebuilt the motor within a couple of days but was demoralized. Sold all the turbo bits and parted the car out. Lost all self respect and bought a POS salvage title miata. :D

Not that anyone asked but there are two things I'm happy with. My stock 84 GSL-SE, 207k miles on the stock engine, tons of Racing Beat bolt ons and the ignition setup above - ran a 14.38@93mph.

With a stock S4 (1986) 13B installed and the same setup as above, car lightened to 2420lbs going down the track - ran a 13.96@97mph.

First night down the track in the miata gave a 17.02@80mph. Painful!