What's a good 1/8th mile time?

[deevergote]

Shuddap... just because I'm the mod here doesn't mean I know everything!

I have no experience with 1/8th mile tracks, and I don't know what a good 1/8th is. I know 1/4 times, and I can easily understand and judge performance based on those numbers, but 1/8th times are meaningless to me. I know there are quite a few people on the board here who only have access to 1/8th mile tracks, and I can't seem to put their times into perspective! When you say you did the 1/8 in 9 seconds, I have no idea whether that is good or not!

So, what's the scale? Where do CB7s generally fall? Like, the F22 1/4 times range from 17 to high 15s... H22 times from mid 15s to mid 14s... stuff like that... where does that all fall in the 1/8th?

[That1guyN8]

I'm really glad you brought that up because I get sooooo confused with 1/8 times. Like you said, 1/4 times are easy to understand.

1/8 times =

[Backfire32]

im not sure but i know that i hit 10.5 on my old setup, IHE and auto tranny. hit 10 flat tonite on t3 at 7.8psi, and i suk at launhing with trying to get traction.

[accordtunerx]

there's no real formula for calculating 1/4 time from 1/8th mile time since everyone's trap speeds vary when it comes to 1/4 mile runs and every car performs different at different speeds. but generally.. a 9 second 1/8th mile time means somewhere in the 14-15 second 1/4 mile range from what i've seen/experienced. for example, i've gotten 9.7-9.8 1/8ths with 15.0 1/4 times.

what i sometimes do to get a ROUGH estimate of where a car is at in the 1/4 mile from an 1/8th mile time.. is take the 1/8th mile time and divide it in half.. then add THAT number to the original 1/8th mile time. depending on whether that original 1/8th mile time is really low or really high.. i'll determine how much to give or take off in either direction. for instance, if a car runs a 10 second 1/8th.. i'll add the 5 and then some.. so probably somewhere in the 16's. however, if a car is running 8's.. i'll add the 4 and leave it alone.. it's probably running in the 12-13's. BUT if its running 7's or something.. i'll add the 3.5 and then actually take OFF some..

ALSO the tenths of a second make a huge difference in this case since its on a smaller scale.. so the difference between an 8.5 and a 9.0 could be as much as a second. so keep that in mind.

meh.. but this is just my inaccurate measurement. there are so many variables here, but i'm happy with a ballpark figure. you really have to just make good guesses.

anyone know of a more accurate or mathematical way? i'm kinda curious myself

[deevergote]

I figured someone would read it that way... I tried not to make it sound like that!

I know that some cars, like turbo cars, will have faster 1/4 times relative to their 1/8 compared to NA cars, since their power comes on later. I don't think there really is an accurate way to find the 1/4 from the 1/8.

I'm just asking what an accurate range for the 1/8 is for our cars.


For example, using what I know... I know that a mid 16 to a mid 15 in a fairly stock CB7 is pretty decent. I know that 15 to 14 is decent for an H22. 14-13 for an F22t, and 13 and below for a proper H22t with traction
I can rattle that off the top of my head, and when I hear that a CB7 with IHE on an F22A1 ran a 16.4 (93twodoorLX's most recent) I know it's not too bad!

[93twodoorLX]

1/8 mile means nothing to me also but i was at the track the other nite and i hit 10.5 which is my best to date, and that is with hard launch and wheel hop but i turned out my best 1/4 mile to date also which was im ashamed to say 16.401 isnt that bitch that i was a blink away from 16.3, keeping in mind that i was fully furnished and had all kinds of shit in my trunk, if i were to strip i would prolly lose like 150lbs so im shooting for 16.0 and lower and i still have stock clutch, suspension, f22a1, and nothing but I/H/E and the relative humidity was 100% according to my track slip...sorry to get off topic i was just waiting to get that out and no one else cares lol

edit: reading just pwned me i didnt see that deev mentioned my time sorry

-sean

[ACCLUDE91]

For your 15 sec 1/4 mi. pass that you said you got a while back, your 1/8th would be somewhere around 10sec. Maybe longer since that H22 has more topend power than the anemic single cam F-series. I'm guessing your trap speed on the 1/4 woulda been somewhere around 92MPH or so and the 1/8 speed shoulda been like 60-something MPH. The 1/8th isn't a good test to see how fast your car is cause it's just not enough time and and distance to really open her up and see what she's got. It's more like to test your reaction times and to practice launching without losing traction.

[MRX]

i only scanned through these posts but thats not a good way to calculate 1/8th mile times guys.

:Bell rings: Ok everybody take your seats. We'll begin with the calculation from 1/8th mile ET's to 1/4th mile ET's today. A great way and solid way to calculate 1/8th to 1/4th mile times is to multiply the 1/8th mile time by 1.56 for normal n/a cars and as low as 1.53 for forced inducted cars. That hundreth of a difference stems from your top end power meaning 70mph+. If your an n/a person and have substantial bolt-ons and are making considerably more power than stock you can use 1.55 as your number.

Now, my last recorded time in the 1/8th was a 9.24 back in like december. Multiplied by 1.53 and 1.54 i could have pulled off a 14.13-14.22 at that time. JamiePatterson the guy with the h22 w/bolt-ons and a 75shot was running an 8.08 on slicks. He himself was using the same method of calculating i was and we both came up with a 1/4th mile of about 12.4-12.6. Simply put, if you don't misshift or have something fall of the engine then using 1.53-1.56 as your multipliers is a great way to judge ET's.

Something most ppl forget is the trap speeds. If you've noticed any of my posts about ppl's track times i always ask for the trap speeds. The trap speeds can damn near tell you the power to weight ratio of the car no matter the ET. My 1/8th mile traps were about 75-76mph. Well with this number you can pretty much add 20-22mph depending on top end power to that number and get my 1/4th mile trap speed. So basically on my very best run i would have pulled a 14.1@98mph. Its pretty much known that if you can break 79-80mph in the 1/8th or 100mph in the quarter then you can break 13's with a good launch, traction and excellent shifting.

A Mustang 5.0 i ran was doing 8.98's@79mph in the 1/8th...in the quarter he was doing 13.9's@101mph.

A GSX i ran was doing 8.7's@82mph...he ran a 13.5@103mph

(waxed them both by the way ...badly )

And to prove the theory on trap speeds...JamiePatterson got a 8.08@88mph i think and 2point6 had like 8.1'-8.2's@86-87mph. 2point6 ran 12.7's@107-108mph and had 247whp...Jamie dyno'd at 256whp or so meaning he'd run better times at faster traps and it all makes sense.

In conclusion add roughly 20mph to the trap speed and multiply the ET by 1.53-1.56 depending on power adders. Also remember that some ppl can't keep traction or can't launch so if your one of these ppl don't get discouraged with your times! I've misshifted and ran 10.3's before at 76mph! That same trap got me low 9's. So this means don't go around racing ppl that trap 90mph or above no matter what their times are unless you've got some SERIOUS power. Thank you, class dismissed.

[ACCLUDE91]

So this means don't go around racing ppl that trap 90mph or above no matter what their times are unless you've got some SERIOUS power.

I will be one of these people soon enough....just a little more tweaking.

Great write-up and explainations. I think that's exactly what deev was looking for.

[deevergote]

Actually, I wasn't looking for a conversion at all... just an idea of what a good 1/8th time is. It never hurts to learn more than I bargained for though! Thanks Antoine!

Now that I know the conversion, it all makes even more sense to me!

[Backfire32]

damn antoine, u need to run the 1/4 or 1/8 so u can give us turbo f22 guys a idea on what we should be around when running them. the cars u beat ran 8.8 and 8.9! and u killed them bad! i really am curious on what u will run. i know that the wrx i ran claimed that he ran 9.2's in the 1/8 and i was pulling pretty hard on him in 4th,.

hurry up and run the 1/4 on ur current setup foo!

[MRX]

can't the manifold is cracked and leaking so bad i couldn't even trap above 77mph@10psi when i was doing 76@6-8psi the first month i got it running. And that 6-8psi was still 30whp under where i had it

[MRX]

More factual data for your calculations

On each of these setups take the quarter mile time and divide it by the eigth mile and you'll get about 1.53-1.56. Then add 20-22mph on top of the 1/8th mile trap speed and check it against the actual quarter mile trap speed.


B16 with i/h/e/etc. on 75 wet shot and slicks

0-60 Foot ET: 1.870
1/8 Mile ET: 8.074
1/8 Mile MPH: 86.984
1/4 Mile ET: 12.612
1/4 Mile MPH: 107.524

WRX wagon with FP green turbo

0-60 Foot ET: 1.71
1/8 Mile ET: 8.138
1/8 Mile MPH: 85.05
1/4 Mile ET: 12.798
1/4 Mile MPH: 104.63

EG with H23 and i/h/e

0-60 Foot ET: 2.00
1/8 Mile ET: 9.1
1/8 Mile MPH: 74
1/4 Mile ET: 14.2
1/4 Mile MPH: 97

h22 prelude with cams, clutch, and V-AFC

60 Foot 2.308
1/8 ET 9.716
1/4 ET 14.929
1/4 MPH 94.23

60 Foot 2.300
1/8 ET 9.613
1/4 ET 14.828
1/4 MPH 94.03

60 Foot 2.400
1/8 ET 9.727
1/4 ET 14.937
1/4 MPH 94.17

60 Foot 2.420
1/8 ET 9.711
1/4 ET 14.928
1/4 MPH 93.89

60 Foot 2.501
1/8 ET 9.891
1/4 ET 15.109
1/4 MPH 93.91
^^^notice that his trap speeds basically remained the same no matter how bad he launched.^^^

STI with a K&N Panel, TBE, and Cobb AccessPort EM

0-60 Foot ET: 1.765
1/8 Mile ET: 8.255
1/8 Mile MPH: 83.25
1/4 Mile ET: 12.990
1/4 Mile MPH: 103.28
^^^even tho it pulls 12's...i wouldn't hesitate to race him from a roll based on his trap speeds.^^^

notice how both the AWD's get great times but don't trap all that high. Thats the beauty of AWD and 1.6-1.8 stock 60fts.