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First time at the drag strip, got my times.


Milenko2121

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Well just got back from the drag strip and did two passes. The third pass my drive shaft u joint grenaded :(

 

I was really shooting for 13s and I am close. My second pass was 14.115 at 99.69.

 

First pass is on the left. I got a horrible R/T because I didn't know how the lights worked.

post-26144-0-70110400-1474940843_thumb.jpg

 

Here's videos of the passes

http://youtu.be/eEkHWlQHc9Y

http://youtu.be/3PBfiF4O1xE

http://youtu.be/J0CCbaGx0rI

 

Also, could someone give me an idea on my times on the slip? I've never really understood what to compare it to. Basically, what did I do bad in, and where was I doing ok?

Edited by Milenko2121
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Well, you're having the same problem I am, getting off the line.

 

The 14.1 pass has a much better 60', which is an indication of a better launch than the other pass.

 

If you can get the 60' down, that's where you'll find your 13 second pass. If you compare the two passes you'll see that the same .2 of a second difference from the 60' is pretty much carried through the entire pass. Because of this it seems that your car is working well, once you're past the 60', so get the launch down and you'll be there. I say that it's working well, because there was no additional drop in E.T. after the 60' from one run to the next. Usually if there's anything to be gained throughout the entire run, you'll see approximately 2 tenths dropped off the 1/4 mile E.T. for every 1 tenth dropped off the 60' time (general rule of thumb). This is not shown in your case, so, just work on those launches.

Reaction Time (RT) has zero effect on actual E.T. This is only an indication of how quickly you reacted to the light going green. I usually wait until the last yellow is just turning off and let out the clutch, usually with in the .500 to .600 range when I do this (.500 is a perfect light on a sportsman tree). Reaction time only really counts when you're trying to actually race and beat someone. Some races are won on reaction time alone, when two cars that are so evenly matched make the exact same pass, teh one with a quicker reaction time will win. ;)

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What type of 60ft should I be expecting on street tires?

I think I was just launching at too low of an RPM (around 3k). The 3rd pass where my driveshaft exploded is when I tried launching around 4k.

 

Thanks for the info on the RT. I didn't know that wasn't factored in.

 

I need to figure out my shifts points too. I haven't dyno'd the car and I don't even know where my powerband falls off. I'm reviewing my AFR logs and I was running too rich. Around 10.5 at full boost. So that's definately sappin' some power. I need to dial back my afpr a few turns.

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Oh, you're running boost?

 

Yeah you should be able to hit 13s easily. I was consistently low 13s with a tired L28 and street tires. Although I was running upwards of 17 PSIG of boost, you're probably a lot lower than that.

 

The 60' time is about what I was able to achieve, but I never did get my launch tuning sorted out, I got it close, but not as dialed in as I would have liked. I would launch around 2500 RPM, for best results in my case, I was running a 3.90 diff and ZX 5-speed. I was shifting at 6000 RPM, and would sometimes short shift 1st to 2nd at about 5600 RPM.

 

Are you not able to actually tune the Z31 ECU? That will help open up a lot of power and get you where you want to be.

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Best way to lower the 60' is with a set of Mickey Thompson ET Drag 26X8.5X15 slicks from Summit and a spare set of 15" rims.  Get 15X7 4.5 backspacing Weld Draglites from the local speed shop used hoard or from Craigs list.  You want the dual pattern 4X4.25 and 4X4.5 that the 4-lug mustangs use.  They use special lugnuts that are available from Summit too.  And get a spare driveshaft and a pile of u-joints and get good at replacing them.  A trailer is nice for broken cars too.  With the slicks, start with the air pressure at 20psi until you get used to the way the tires sway at speed (you just have to get used to the car using ALL of the lane).  Decrease the air pressure until you get your best RTs.  My best RTs with a manual trans is with just a little tire spin (not enough to make noise).  If you dead-hook with a manual trans, you will break something.  Auto trans cars do best with a dead hook of the tires and the torque converter does the controlled slipping. To get those times with all that tire spin, you have a good powerplant-nice job!  Be warned, if you really try to lower your RT, you will find weak links in the drivetrain.  And I would discourage you from trying to slip clutch a lot to avoid tire spin: you will just cook your clutch.  Dump the clutch (quick release, not a side step) and let the slicks do the controlled spinning.  That's my way, I'm sure others have good ideas too.  By the way, I wish I had a nice girl in the stands cheering for me that way-nice catch!  Sounds like a keeper.

 

I tried to upload some videos but this website has changed and I can't cut and paste in the link, but go to youtube and search for RebekahsZ or Keith Thompson and you should find some slow-speed videos of my car launching.  Mark a line on your tire and you can slow your videos of the tires so that you can start learning about acceptable tirespin.  Maybe more than you wanted to know, but I love this stuff!  Oh, BTW-my timeslip is from a 1/8 mile, so don't freak when the mph and times don't make sense compared to your time slip, but 60' is 60' on any track of any length.

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post-5903-0-85624000-1407910765_thumb.png

Edited by RebekahsZ
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I did a lot with street tires. If radials I had some good luck running high pressure. 35lbs. As Rebekahsz said control the tire spin but don't burn the clutch. When setting the second bulb use the e-brake to stage. Hold the button in and try to pre-load the driveline. This eliminates the shock load value when putting the power down.

 

When launching the car, release the e-brake all the way (don't need full on braking) at the same time you engage clutch.

 

Tough issue is boost and lag. I was able to get under 2.0 doing this. 1.94 being the best. But that would put you in the 13.6 to 13.8.

 

Practice.

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Do you know how do they define street tire?  At our tracks, a street tire is anything that is DOT rated.  That opens up drag radials and DOT bias ply tires that have a couple of grooves in the tread:  Hoosier Quick Time Pros, Mickey Thompson ET Street, which is their ET Drag bias ply carcass with a couple of grooves in the tread.  Would I drive these tires in the rain - heck no, but they are technically street tires.  On those "street" tires, there are street-legal turbo mustangs running  low 4s in the 1/8.  Check it out, you might find that street tire is defined pretty loosely.  A 2-step really helped my launching, if you aren't familiar with a 2-step, give it a google.  It lets you floor your gas and concentrate only on clutch.  Otherwise, with daily driver grocery-getter tires, the only way I know to control wheelspin is with less power, which means less rpm.  The 2-step really helps with this: you can set your launch rpm.  You can start at 2000rpm and adjust from there: if you spin, lower the rpm.  If you bog or kill it, then raise the rpm.  The 2-step gives you reproducibility-it lets you control one of the hardest parameters to maintain when you are nervous at the line and distracted by the lights.

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E.T. and MPH are not tied together. Most of the time my quickest passes are some of my slowest, meaning the E.T is low, but the MPH is also low, compared to some of my slower passes (E.T wise). Usually this is an indication of one run dead hooking and applying all of the power, while another is slipping at least a little bit, or slipping more than another run.

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Well just got back from the drag strip and did two passes. The third pass my drive shaft u joint grenaded :(

 

I was really shooting for 13s and I am close. My second pass was 14.115 at 99.69.

 

First pass is on the left. I got a horrible R/T because I didn't know how the lights worked.

20140809_014228.jpg

 

Here's videos of the passes

I

 

Also, could someone give me an idea on my times on the slip? I've never really understood what to compare it to. Basically, what did I do bad in, and where was I doing ok?

are you in Las Vegas? Wait for it to cool down also, out elevation and temps suck donkey balls. Edited by Meatwad
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I'm running 225/50-16 Dunlop Direzzas.  They are a high performance summer tire and really sticky. With the right launch set-up you should be able to get your 60' to 2 seconds or less.  That is what you need to target. Then if you get your reaction time down to about .1 second (learning to pace the lights) you can go heads up with other cars.  My first time out my R/T was slow and the car in the other lane was halfway down the strip before I got going.  His R/T was less than .1 and he had a big block that put him in the mid 10's.  Pretty humbling. Improving your R/T won't improve your 1/4 mile time but it will make you more competitive in heads up racing. 

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I'm running 225/50-16 Dunlop Direzzas.  They are a high performance summer tire and really sticky. With the right launch set-up you should be able to get your 60' to 2 seconds or less.  That is what you need to target. Then if you get your reaction time down to about .1 second (learning to pace the lights) you can go heads up with other cars.  My first time out my R/T was slow and the car in the other lane was halfway down the strip before I got going.  His R/T was less than .1 and he had a big block that put him in the mid 10's.  Pretty humbling. Improving your R/T won't improve your 1/4 mile time but it will make you more competitive in heads up racing. 

 

I believe at my track, a perfect is .500.

 

I'm running 225/60-14 BF Goodrich Radial T/A. I believe my issue is mostly the size of my rims. They're 6" maybe 5.5" so I'm not getting full contact.

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A couple of things.  Phantom-what is the treadwear number on the Direzza (that's a great tire), in case his "street tire" class limits him to a certain number?  Milenko212-the Goodrich Radial T/A is a terrible tire from a traction standpoint.  All the hotrod guys run them and I have them on my S10 pickup, and I hate them.  They are awful, and if there is ANY rain on the street I can barely get the truck stopped.  They are very hard compound and last FOREVER, and they look great (why I bought them).  Just about any tire is going to be better than them.  If you go to the local hotrod hangout, look at the cars running the Radial T/A, you will find that underneath the Armorall, they are dry-rotting before they wear out.  I will probably keep the T/As on the back of my truck and just burn them to the cords, but I am just about ready to pull the trigger on some stickier front rubber so I can get this truck to stop better. Stopping or starting, traction is traction.  Also, important to know that traction declines due to age.  About a decade ago, I bought some brand new race tires and put them on the shelf because I had big racing plans.  My in-laws moved in with us, I changed jobs, blah-blah-blah, and I didn't race for several years.  When the smoke cleared and I started racing again, I mounted those tires up and it was like driving on ice.  I walked around the pits doing the fingernail test on my tire compound and with racing tires I had harder tread than the guys with new street tires.  Tires are the stickiest the day you buy them.  Also, check manufacture dates-a lot of discounters have tires on the shelf that are several years old when they get to you.  A 2.0 is a very respectable goal if you are restricted to street tires.  Also, lighten up if you can:  pull your spare tire, jack, tool kit, subwoofer etc out of the car, get lighter seats.  Power-to-weight is cheap horsepower. Finally, let some air out of your rear tires to improve contact patch (cheaper than new rims).  What pressure were you running?  You could easily let the tire pressure down progressively to as low as 15 psi and pick up a lot of contact patch.  I wouldn't do it all at once: if you are running 30 psi now, drop to 25, then 20 and see if it helps.  Finally, what is the track prep like?  Do they spray it down with VHT really good, and how far out from the lights?  I race at tracks that prep well and I can go mid-1.4s, but at other tracks, I'm struggling to go 1.6s.  Traction doesn't just happen, there are a lot of variables.

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Thanks for the info on this tire. I did not know that. They were just the biggest tire I was able to find that'd fit on my 14" rim and keep stock tire diameter.

 

As far as pressure, I was running 30psi. I wasn't sure if I should run less since they're a street tire. I may try the 25psi on my next trip to the track in September.

I've removed all the spare tire stuff and I'm running Sparco R100's. Lightest seat I've ever owned. I can curl them with one arm moderately easy and I'm a light built guy, haha.

 

The track prep was top notch. Even when I broke the driveshaft when I stepped out of the car, my shoes were sticking to the track halfway down. Their clean up crew was awesome as well.

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