I just wanted to dispell the myth that cutting a better 60' will reduce your trap speeds. I hear all the time "...yea, but if you cut a better 60', your trap speed will go down..."In fact, trap speeds will slightly increase if the better 60' time was due to better driving. but spinning tires on purpose to increase trap speeds WILL NOT WORK! The faster you get to the 60' in seconds, the faster your travelling when you get there in MPH.
The basis of the myth is on some people's observation that reduced 60' times due to better tires and/or lower tire pressures decrease trap speeds. This IS TRUE for the most part, although it's not a certaintly. The reason trap speeds decrease when switching to better tires is because rolling resistance increases. Softer, stickier tires are harder to roll at speed than hard, non pliant tires.
Let's say driver A is a mediocre driver who can cut a 2.303 second 60' time and trap 86.43 mph. He is disgusted with his ET of 15.93, so he lets his friend, driver B, take the wheel for a pass. Driver B cuts a bit more respectable 2.203 60' time and traps 87.99 mph. Hmm, no other changes to the car, just driver input on launch. Neither one missed a gear, and both driver's went through the traps at the top of 3rd gear. Interesting, but the story is a bit misleading because in real life, I was both drivers. Just needed a couple passes to warm up. Both of those passes were on the same day, back to back, no changes in weight, or driving technique, exept on the launch.
Here's another example.
Last year my best 60' with Azenis tires on the 100 shot was 2.238 with a trap speed of 103.59 mph. With no other changes except bfg drag radials, my best 60' was a 2.031 with a trap speed of 103.57. So even with stickier tires at a lower pressure, trap speed was only reduced .02 MPH. And on an interesting side note, I forgot to disable the VSS on that run. On a backup run with the VSS disabled, I cut a 2.078 60' time with a trap speed of 105 mph. Hmmm, I could have gotten a better trap on that other run I guess, even with the stickier tires. That's why I say it's still not a certainty.
So for all you who insist that trap speeds ALWAYS go down with better 60' times, you are just plain wrong, and I have proof in my timeslips. There may be an occasion where that happens, but only due to increased rolling resistance, and/or driving variances in the last half of the track.
I wanted to write this post for some time, but it didn't bother me enough until the recent post where people were arguing about this very subject in the top 5 lists thread. If you disagree with me, that's fine. But I don't want or need a bunch of bs and hearsay to litter this thread. Show proof or keep it to yourself.
*Disclaimer---I'm not trying to create another myth in place of the one I am debunking. trap speeds might go down in some cases as I stated, I'm just saying it's not a given that they will. They might stay the same, go down, or go up. There are many more variables in driver technique, and weather conditions that can skew results. But the change in trap speeds due to 60' times are completely negligable compared to those other variables.
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I agree with you, out of 8 runs.. my best ET had the highest MPG to go along with it with.
i have some time slips that i messed up the launch bad.. like 2.7 bad.. and still got 110mph with some launches as good as 2.2 and got 110mph trap speed.
but the argueing never ends on j-body.org
-DJ
Great point, that's why formulas to figure out horsepower by 1/4 time goes off trap speeds not et.
2000 Turbo Z
Speaking of which, here's a great calculator. I've been to a chassis dyno and this calculator was within 2 Hp of the actual number, although I might have been a couple pounds off since I was estimating how much gas I had for that run.
http://www.smokemup.com/auto_math/hp_mph.php
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^^ im not a member.. you think you can check my HP?
wieght 2400
trap speed 113
drive train loss, i dont know, its a 5 speed with solid bushings all around and tight suspension, lightened flywheel, no a/c condensor.
-DJ
DJ Ruiz (DJClueless) wrote:^^ im not a member.. you think you can check my HP?
wieght 2400
trap speed 113
drive train loss, i dont know, its a 5 speed with solid bushings all around and tight suspension, lightened flywheel, no a/c condensor.
Your car only weighs 2400 lbs? Shiat, no wonder you're trapping 113! My car weighs 300 lbs more than that (of course it's fully loaded) Anyway, says here you're putting down 235 Hp to the wheels, only 4-5 more than me (that will change as soon as I install this!!!!!!)
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Bwhahahahahaha! Maybe I need to do some weight redux too!
At an estimated 15% drivetrain loss, that puts your flywheel Hp at 276. About 4 under what considered a dangerous power level for a stock bottom end on an Eco. If anything, tuning should be your best friend right now, and no more boost until you're built!
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nitro..>quit bein a fag about a post i put up<
Jordan, quit being a disrespectful newb. Oh, and prepare for a ban, a$$hat. Calling me names in every one of the threads I post in is not going to get you on anybodies good side.
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Its not my fault u have to comment on everyone of my posts.
nitro: good post.
I kinda feel like driver A
15.958 @ 88.201 stock, still getting @!#$ty launches...
jordan bjerke wrote:Its not my fault u have to comment on everyone of my posts.
Grow up, kiddo, You've got alot to learn before you start opening your mouth around here. Besides, you only have one thread so far, newb.
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Im sorry bout bein an ass. As you can tell im really stubborn.
my cars slow but ill throw in my .02 and agree with you to some extent
2.2 OHV 5spd.....
my best 60' of 2.465 gave me a 82.27 trap
compared to my 2.515 i pulled last time had a 83.70 trap
looking over my slips, about 75% of the time when i cut a faster 60' my trap speed is slower (only by VERY little).....however like i said the other 25% of my runs go the other way, but in the end the faster 60'=faster 1/4 mile
Jordan, I was once a hyper 15 year old too, ya know. I can let it slide, even more than once. Take some time to read up in various forums and soak up some info. You can usually tell who knows what they're talking about by looking at their experiences. For instance, I'm experienced with nitrous use, and drag racing. Some others are suspension and autoX guru's. While others still are turbo guru's and so on. To get along on this site, it's important to know the "rules of engagement". I wasn't trying to be a dick when I told you you were posting in the wrong forum. It specifically states on the top of the page of this (racing) forum that street racing or who would win thread do not belong here, but in the VS forum. Learn to navigate this site the way it was meant to be used, and you'll do just fine. And also expect to get your share of "newb initiations" and all the internet razzing / flaming that goes along with it. Sometimes people answer "who would win" threads. But usually it gets answered by the suggestion to go find out for yourself by actually racing the guy. I put my two cents in if I think it's intruging enough. But (no offense) trying to guess which 17-18 second car will win between two equally slow cars isn't gonna get great responses around here. I'll be seeing you around, and I promise not to give you too hard a time unless you really deserve it, lol. Now let's get back on topic and stop the threadjacking!
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Good Post Nitro, I couldn't stated it better myself.
Opening up your exhaust might allow you to run 12's without any other changes.
But I have to stress how important suspension tuning is on a drag car.
You don't have to give up your street ride quality to get good ET's, But you do have to stop chassis squat and dive.
Tein has Super Street Dampers with rebound and compression adjustment and ride height adjustment. They aren't available yet, but these would be a sound investment in your car.
When you tune coilovers, find a racing shop that has corner weights and try to balance your car the way you race it with your weight simulated in the front seat.
On the subject of slower trap speeds with better 60fts, its possible but harder with drag radials because they don't have the same issues that bias-ply tires have when you run them low on air pressure.
9 times out of 10 slicks will slow your trap speed down until you find an air pressure setting that not only gives good short times but doesn't drag the car down on the top end. Your ALIGNMENT has alot to do with it as well....
1995 Plymouth Neon Highline - Magnum Powered!
wow, my first time at the track i cut a 2.2 60'
Quote:
^^ im not a member.. you think you can check my HP?
wieght 2400
trap speed 113
drive train loss, i dont know, its a 5 speed with solid bushings all around and tight suspension, lightened flywheel, no a/c condensor.
hey dj, how did u get yoru car to 2400 lbs?
my 2004 base model weighs 2600lbs without me in it.
John ^ I would go read his novel of a registry for his 97 eco project. lol i just did
