Re: Excessive braking calculation?
[Re: 340Cuda]
#2735589
01/22/20 01:28 PM
01/22/20 01:28 PM
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Joined: Jan 2003
Posts: 20,179 Park Forest, IL
slantzilla
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 20,179
Park Forest, IL
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If there was no smoke, no excessive braking as said above.
That said, it's really hard to knock off a lot of ET just slowing and braking at the big end. I've scrubbed 30 mph off a 130 mph bike and only lost .3. Trying to slow down a fast car over a second is a big order.
"Everybody funny, now you funny too."
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Re: Excessive braking calculation?
[Re: SportF]
#2735595
01/22/20 01:43 PM
01/22/20 01:43 PM
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Joined: Dec 2005
Posts: 11,579 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,579
Fulton County, PA
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He was too far down track when he tried to get it slowed down predictably. Obviously he left after you. His tactics were lousy. He should have caught you mid-track somewhere and fender raced you.
If the results don't match the theory, change the theory.
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Re: Excessive braking calculation?
[Re: CMcAllister]
#2735618
01/22/20 03:00 PM
01/22/20 03:00 PM
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Joined: Jan 2008
Posts: 1,212 Minn
SportF
OP
pro stock
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OP
pro stock
Joined: Jan 2008
Posts: 1,212
Minn
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I was 10.50. He was relatively new to the car, and I believe, but don't know, it was the first time at that track.
I had heard his previous 2 time trials were both spin fests, so when I found I was matched with him it wasn't with regret. He had already told me the car was high sixes capable, but turned down for this track, max et limit of 7.50. So, I am guessing the 8.0 dial was guessed, with some spin thrown in.
If you use a Wallace calculator the 7.86 is way off from the 140.56mph. His 1/8 mile mph was 150.05, which in the calculator shows up to be a 7.18 at 185. Also, his 1000 foot was a 6.427 and the calculator shows that to be a 7.80 and 170mph.
So, some speed was scrubbed, when did that happen, in the last 300 feet? And, has somebody who runs that kind of ET, how hard on the brakes does that take?
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Re: Excessive braking calculation?
[Re: nss guy]
#2735670
01/22/20 07:58 PM
01/22/20 07:58 PM
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Joined: Jan 2008
Posts: 1,212 Minn
SportF
OP
pro stock
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OP
pro stock
Joined: Jan 2008
Posts: 1,212
Minn
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That I don't recall, but I don't believe so. He didn't come around after the run, and getting mine ready for next round I didn't look him up (although he was basically across the pit road from me). I had went over to talk to him when he fired the car up to pull it out of the trailer. I basically said that he had the badest sounding car on the property, and it was at that point he told me the car was capable of high sixes. I don't believe there was any dragsters that fast there that day, but as I said, the track has a 7.50 max et anyway. This was a 69(?) Firebird with a blower, a go to town kind of blower, on a tube chassis. I'm sure it was the fastest car there, and the fastest I have ever run.
Last edited by SportF; 01/22/20 08:00 PM.
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Re: Excessive braking calculation?
[Re: SportF]
#2735726
01/23/20 01:46 AM
01/23/20 01:46 AM
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Joined: Aug 2003
Posts: 43,195 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,195
Bend,OR USA
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My N/A single dominator carb E85 motor in my 2750 Lb. S/P bracket car has ran 8.864 at 148 + MPH all out and then by upping the 1st to high gear shift RPM(powerglide tranny) from 7000 RPM to 7300 RPM ran 8.886 at 150.+ MPH My message is once you get near 150+ MPH HP comes into play a lot the last 300 Ft. in the 1/4 mile For him run that quick at 140 MPH tells me he was on the brakes hard before the finish line, not just off the throttle only
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Excessive braking calculation?
[Re: J_BODY]
#2735810
01/23/20 11:59 AM
01/23/20 11:59 AM
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Joined: Jan 2003
Posts: 19,367 Las Vegas
Al_Alguire
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 19,367
Las Vegas
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How about this answer. Since you really have NO IDEA what the car can or wqas actually going to run you have zero clue as to how much MPH he killed. Suffice it to say if he was going 150 at the 1/8 he killed PLENTY of MPH. You could say he would EASILY gain 35-40 mph on the back half, typically dragsters do not have the back half mph of a door car why the wide margin I stated is 5mph.
Jay while I agree with you that running it to 1000' is preferable there is NO WAY a car going 7.0/190 is killing 5 tenths in the last 320'. He is simply covering to much ground to quickly, at those speeds he is likely covering 260-270feet per second at the 1000' cone.
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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Re: Excessive braking calculation?
[Re: SportF]
#2735860
01/23/20 03:06 PM
01/23/20 03:06 PM
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Joined: Feb 2005
Posts: 20,175 PA.
pittsburghracer
"Little"John
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"Little"John
Joined: Feb 2005
Posts: 20,175
PA.
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Before keystone started running my class 1/8 mile my buddy wth a car that could run 4.60’s in the 1/8th would let off at the 1/8th or 1000 foot stripe and coast the rest of the way. That way he still got the 1/8 the mile info he needed and could still race without packing a chute. He got pretty good at dialing the car that way. Lol.
1970 Duster Edelbrock headed 408 5.984@112.52 422 Indy headed small block 5.982@112.56 mph 9.42@138.27
Livin and lovin life one day at a time
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Re: Excessive braking calculation?
[Re: SportF]
#2736402
01/25/20 06:27 AM
01/25/20 06:27 AM
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Joined: May 2008
Posts: 5,399 Aurora, Colorado
451Mopar
master
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master
Joined: May 2008
Posts: 5,399
Aurora, Colorado
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If you have the speed at 1,000 ft, you can calculate the average breaking G-Force in the last 320 feet. Example Initial velocity @ 1,000 ft (estimate) 170 MPH Took time to go from 1,000 feet to 1320 about 1.441 seconds Average deceleration would have been about -1.1762 G? That seems pretty hard braking, but if he was just 160 MPH at 1,000 ft, that is only -0.5435 G ? Here is the calculator I found: https://www.omnicalculator.com/physics/acceleration
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