Competition ET vs. MPH

[Bob Wagner]

How do you calculate the difference's?



It someone has a lower ET but also has the lower MPH



what does this mean?



how do you decipher the time slips?



thanks

 

[Jetpilot]

Good question... ... I ran a 12. 26 @ 118 in Muncie yet DD says they ran a 11. 96 @ 110. When I make a run that sports a 110 MPH I am around 12. 75.



Doug

 

[DHRA]

good question

Could be drag, rear gear ratio, tire size, hp, etc.

I ran a 13. 5 @ 102 with a manual transmission, I had 35" tires too... I didn't increase my horsepower any when I switched to an auto. I ran a 12. 98 @ 102 on 30" tires. I dynoed 27 less hp with the switch.

I recently made a hp change and in a hasty shot to the track before I headed to Seattle, I ran a 12. 74@104. 99. I ran ~250 lbs more than I usually do.

Also, I am locking up the converter right off the line, therefore I have seen some really incredible 60' times. My 1/8 mile was an 8 flat, which is great. Before I made the latest hp mods I ran a "no boost" launch and ended up a 13. 7@ 98mph.

In my case, I think the tires helped on the short times, hurt in the big end, the transmission helped everywhere and the lift kills me all over!

 

[83 crew cab]

check out this sight it may have some thing http://www.smokemup.com/auto_math/index.php

 

[Bob Wagner]

HEY!!!!!! 83 crew cab

Thank you very much very nice link and I appreciate it

 

[KatDiesel]

Originally posted by Jetpilot

Good question... ... I ran a 12. 26 @ 118 in Muncie yet DD says they ran a 11. 96 @ 110. When I make a run that sports a 110 MPH I am around 12. 75.

Compare 60fts... ... ... that will tell you alot.



Also I don't remember but what does your truck weigh Doug? I believe the DD truck was 6400 to 6300 lbs.

 

[CUMINNTSTRKN]

bob

try www.prestage.com they have about everything a guy could want.



jim

 

[Jetpilot]

Eric,



The truck came from the factory weighing 6565 lbs. With the mods I have + driver I am estimating between 7050-7100 lbs. 60' times are around 1. 85.....



Doug

 

[Dak - BD Power]

Compare time slips

Doug, compare your timeslips with Keiths (DD) and you'll see that there was definalty a problem with the lights at the Las Vegas track. I'm not dismissing Keith's time, he was the fastest at May Madness without a doubt.



Doug, I would say that you have the fastest time out of the couple of trucks that compete regularly.



CR

 

[michaelmurray]

MPH is a more consistent method of comparing hp. ET has a lot to do with traction and transmission.

 

[DavidTD]

I have always been told MPH in the 1/4 mile is a good indication of HP being applied to the track. Those that can generate equal times with less MPH usually have lighter vehicles with less weight.



My 2500 ran 14. 85 @ 93 mpg in Muncie yet I saw the time slip of a duramax run a 14. 81 @ 88 mph.



Doug, that is one wild ride you have there sir.



Eric - you are still drug free right? Man that is hauling!!

 

[TomGolden]

Originally posted by DavidTD

I have always been told MPH in the 1/4 mile is a good indication of HP being applied to the track. Those that can generate equal times with less MPH usually have lighter vehicles with less weight.



My 2500 ran 14. 85 @ 93 mpg in Muncie yet I saw the time slip of a duramax run a 14. 81 @ 88 mph.

I have only drag raced at one track, and only a very few times. I'm guesing I am right at 400 HP with my BOMBs. I am also 6 speed impaired for drag racing... My best time slip is 16. 9 seconds @ 92. 1 MPH. I have a faster terminal velocity than guys I race with that beat me by 2 - 2. 5 seconds in ET's.



Tom

 

[DHRA]

I agree with Dak, Doug has the fastest street 4x4 that we know of.

Yea David, still drug free. I am excited too, thanks. I have also been told that MPH is hp. Every 1/4 mile calculator out there gives a different reading/calculation. I know what the dyno says (or did say) and I know what counts, and that is who is at the end first, period...

 

[Snow man]

The mph of Jetpilot(Doug) is absolutely incredible,at 118mph. This is an indication that no one else is even close as far as HP,or his transmission is the only one that will hold lockup thru 4th without slipping. His mph is so much higher than everyone elses,it makes me think it may be transmission related to a point. I hope to hit 100 mph,id be thrilled. last time i was at 97 mph,with a race tc,bigger turbo,and bigger nozzles,i should be there. Eric,your runing incredibly fast considering your lifted,tall tires,and all motor.

 

[DavidTD]

I agree, Jet Pilot has LOTS of HP at work.



Eric - I tried the 4wd launch on a 1/8 track. Best was 9. 1 sec with a 1. 88 60 foot. Going back Thursday night to shoot for the 8's.

 

[HVAC]

Vegas Times Smoke Aided

The time vs ET relationship is an interesting discussion. In vegas I ran slower by 3 mph without the Nos and LPG while at the same time dropped 3 tenths off my best time. The reason of course is we had tires that hooked at the line. Adam (driving) was able to hold 8 psi before launching. The 60' time was better by a full second! And yet we were slower on the top end with straight diesel fuel.



I got to see Jetpilot run at Muncie and his handle is appropriate Didn't know who it was at first.

Just kept swinging my neck around and asking "Who the he** was that in the black truck that just crushed [CENSORED]?"

 

[CTHOMAS]

You Dodge boys sure do hook off the line The best 60ft I have had is 1. 905 and ran a 8. 26 at 84 mph in the 1/8 launching in 4wd. How do you fellows get those low 60 ft times. Don't tell I know y'all make more torque,right

 

[DHRA]

new thought?

Could there be a relationship between 12 valve trap speed and 24v trap speed? I can't remember Adam's 12. 6 run's speed. Adam, where are you bro?

Doug 12. 26 @ 118 24V

Nowel 12. 80 @ 112 24V



Myself 12. 74 @ 104. 99 12V

Jeff Garmon 11. 74 @ ??? can you fill us in Jeff?

 

[fest3er]

Might I inject some math here?

I don't think it is simply top speed that wins 1/4s. It is a combination of top speed and how fast you can reach it that determines ETA. Looking at Eric's numbers, I would hav eto say that Eric is accelerating quicker than Doug or Nowel, even though his top speed is lower.

At 60MPH, it takes 15 seconds to traverse 1/4 mile. Suppose you were to reach 90 MPH at 320 feet and maintain that speed for the next 1000 feet; also assume 0-90 was linear, thus an exact average of 45MPH over 320 feet. The resulting 1/4 miles time should be 12. 42 seconds.

If you reached 90 MPH at 160 feet and held it, your ET would be 11. 21 sec.

If you reached 90 MPH at 60 feet and held it, youer ET would be 10. 45 sec.

Now, let's change your top end.

If you reach 110 MPH at 320 feet, your ET would be 10. 16 sec. 110 at 160 feet, your ET would be 9. 17 sec. 110 at 60 feet, your ET would be 8. 55 sec.

By now, it should be clear that the faster you reach your top end, the faster you will traverse the 1/4.

To reach your top end the quickest, you need *lots* of torque at the wheels, and tires that can connect that torque to the ground. Of course, simple thrust would work as well, but then you'd be out of the diesel class, eh?

An engine that makes 1000 HP at 12000 RPM should accelerate my truck
about as fast as my mostly stock 12V does. Well, maybe faster. After all, it *would* be staying in lower gears longer, thus taking advantage of the torque multiplication of those gears.

Have I adequately muddied the issues now?

Fest3er

 

[HVAC]

Stacker

I'm guessin', but I thought Adam was at about 104 and change. Jeff must be in the 114 mph or better to kick down a 11. 74.



I find your hypothesis intriguing. However, I would add this:



-Your truck is tall which makes it hard to mph.

Same is true for Adam.



-My truck is low, opposite effect on the top end.

Jet's truck is simply makin' a lot of power with that huge Nos shot and that B1 turbo.



Another thing about my truck is that we were not locking the converter till OD. We are flashing the converter pretty bad now. I plan to swap the converter soon so we can use lock more. Gotta leap frog ahead of you Stacks!