ET@MPH

[70bigblockdodge]

7.22 is et at the first mph clock, at 594 feet. (Correct answer).
Edit: roughly .5 sec to cover the last 66 feet.

Hear I thought the track was being helpful.
Makes sense after you point it out.

 

[TN Mopar]

You can use the paper method on DOT tires.
Start high pressure 28 maybe and on a really smooth surface (garage concrete floor is great) try to put paper under outside edge. Keep lowering pressure until the paper does not want to go under anymore (shoulder of the tread is on ground). That's about right pressure and you can vary a couple pounds in each direction.
Uncle Tony did a video on this if you need a visual to understand my poor wording.
More air pressure my give you some tire slip if your having trouble getting up in rpms out of the hole. Fine line before it breaks traction and spins, but that's half the fun is experimenting.

This is great!
Thank you!

 

[Dan64]

7.22 is et at the first mph clock, at 594 feet. (Correct answer).
Edit: roughly .5 sec to cover the last 66 feet.

Well, I just learned something, thanks.

 

[33 IMP]

Hear I thought the track was being helpful.

They are!
When I started racing, you got e.t. and mph if you were lucky. (Electronic pen at the time shack, written down by somebody in the tower. )
You just had to hope you could read it.
Reaction time? What's that? 60 foot? Why would you want that?!?

 

[33 IMP]

I still might be able to find an original Irwindale electric pen time slip..... if the ink hasn't faded away, since the early seventies, lol.

 

[33 IMP]

90 mph is 132ft/sec. So at 90, cover 66ft in a half second, EXACTLY what your slip shows (kinda cool, actually.).

 

[TN Mopar]

I'm glad I posted this
I've learned quite a bit

 

[Cranky]

I'm glad I posted this
I've learned quite a bit

What's your car's combo? Rear end gear is pretty important for 1/8 mile racing. In the 1/4, if you don't have enough gear but a good top end, you can usually run past the opponent on the top end. Hard to do that in the 1/8 mile.

 

[33 IMP]

The 2.33xxxx at the bottom is sometimes listed as M.O.V., .margin of victory. It's the difference in e.t. between the cars, with reaction time added (or subtracted) in, During a real race with dial in, the handicap is figured in too.

 

[TN Mopar]

What's your car's combo? Rear end gear is pretty important for 1/8 mile racing. In the 1/4, if you don't have enough gear but a good top end, you can usually run past the opponent on the top end. Hard to do that in the 1/8 mile.

440 10.7:1 compression .509 Purple shaft Cam Eddy RPM aluminum heads Eddy Torker II intake Thumper 850 billet Carb
727 auto with 3000 RPM Stall
8.75 rear end with 3.91 gear Mickey Thompson ET Street R radials P255/60r 15 (27")
Car weighs 3800 pounds

 

[Cranky]

440 10.7:1 compression .509 Purple shaft Cam Eddy RPM aluminum heads Eddy Torker II intake Thumper 850 billet Carb
727 auto with 3000 RPM Stall
8.75 rear end with 3.91 gear Mickey Thompson ET Street R radials P255/60r 15 (27")
Car weighs 3800 pounds

What is your shifting RPM and what RPM are you crossing at? I'm thinking you could probably use more gear and maybe a lot more but if you are also using your car on the street, you probably won't want to...

 

[TN Mopar]

What is your shifting RPM and what RPM are you crossing at? I'm thinking you could probably use more gear and maybe a lot more but if you are also using your car on the street, you probably won't want to...

Since this was my first trip with this engine I was shifting at 6000
and I dont know my RPM at the finish line
But I wasn't shifting into third until the race was almost done so I am sure its low

but this is a street car
Not a daily driver but I drive her all over avoiding the Interstate

My race Car had a 513 gear in it so I understand it needs more gear for the 1/8th

 

[Dan64]

I entered your tire( 27”) ,your 3.91 rear and the 727 gear ratios and this is what Wallace calculator came up with. You can get lost on that site for hours playing with this stuff.

 

[dvw]

Here is a screen shot of a close to ideal run at 90mph according to Wallace. The second chart is based on the 7.72 ET. Personally I find their 300 and 660 times a little optimistic. But they give you a better idea of what to strive for.
Wallace Racing - Automotive Calculators
Doug

60 Foot	1.66
330 Foot	4.81
660 Foot	7.55
660 MPH	90
1000 Foot	9.93
1/4 Mile ET	11.97
1/4 Mile MPH	110.70

60 Foot	1.70
330 Foot	4.91
660 Foot	7.72
660 MPH	88.05
1000 Foot	10.15
1/4 Mile ET	12.23
1/4 Mile MPH	108.30

 

[dvw]

I put this in a seperate post. This screen shot breaks down exactly what is happening in a bracket race time slip.
Doug

 

[padam]

Really close to my runs last fall
#3 was my all time best I think.

 

[padam]

The last time I ran the quarter was pretty close too.
I think after this I went from 28” rear tires with tubes to 29.5”, without tubes.
Seems like the et should have got worse with taller tires, but maybe the car has too much gear (4.56.)

 

[padam]

Didn’t mean to hijack your thread, and sorry for being “post my time slips guy”, but I need something to get me motivated to climb under my car.

 

[dvw]

We've found a loose converter will reduce ET more than a lower gear in most cases. So the taller tire reduces gear but may not slow it much.
Doug