mopowers
Well-Known Member
2 mins with the Wallace calculator will get you your answer, or close to it.
100 pound loss = how much HP gain???
- Thread starter 318willrun
- Start date
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I've tried, about as ball park as the rest of the internet. 6 - 10 hp per 100 pounds. That for a 1000 pounds, say going from a 4200 pound Fury to a 3200 pound Duster would tell you that 60-100 hp would be needed. So what is it? 60 or 100 hp needed??? Big range there and what you would need to buy to get it....
mopowers
Well-Known Member
Wallace calculator says 12.5 at 3000lb takes 303.6 hp. Whereas 12.5 at 3100lb takes 313.7 hp. 12.5 at 4500 lb takes 455.4 hp. All according to Wallace calcs.
So, ~ 10 hp at the 12.5 second 1/4 mi ET level.
At the 10.0 sec level, 3,000 lbs takes 593 vs 613 at 3100 lbs.
As already stated, the scale IS NOT linear. Define the 1/4 ET or MPH, then you will have your definitive answer. ET-MPH-HP Calculator
So, ~ 10 hp at the 12.5 second 1/4 mi ET level.
At the 10.0 sec level, 3,000 lbs takes 593 vs 613 at 3100 lbs.
As already stated, the scale IS NOT linear. Define the 1/4 ET or MPH, then you will have your definitive answer. ET-MPH-HP Calculator
That is what I was looking at also. But, the faster you go, the more HP it takes to lower the ET. But no matter how fast you go, a 100 lbs should create the same equivalent hp regardless on how much that drops your ET. So, Wallace is really saying X weight and ET = X amount of HP. But, no matter the ET or MPH, what is 100 lbs loss equivalent too in HP gains? If it's 8 hp, I understand that 8 hp doesn't effect the ET slip of a 10 second car like it might a 20 second car. I'm not trying to figure out how HP effects the ET slip, but rather how much hp does it take to equal the same effect as losing 100 lbs
No, It become exponential because the faster you go the harder it is to push the air out of the way. The car has the run through the air. That’s a drag and pressure. The air is pushing against the car. The faster you go toward pressure (air) it increases the need for horsepower exponentially. The same with weight. Air is weight against the car.
While a loss of weight may equal more HP in time, it’s the available power needs to go faster grows huge. As said, this is not a linear thing.
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mopowers
Well-Known Member
Look at the numbers I posted. 100 lbs is equivalent to about 10 hp at the 12.5 sec level, whereas 100 lbs is equivalent to about 20 hp at the 10 sec 1/4 mi level. The scale is not linear. What those numbers tell me is that weight is more important as you go faster.
For ***** and giggles I ran the numbers for an 18 sec car. 100 lbs is about 3 hp at that level. Once again - not linear (diminishing returns).
famous bob
mopar misfit
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
correcto mundo , lets the car move quicker if the traction is there .
My car is an oddball and I think the way I have it setup to 60 foot messes up the numbers. Granted the fact that my class now runs 1/8 mile at every track we race at the numbers were off even before when we did run 1/4 mile. My sons about 100 pounds lighter than I am but we both 60 foot in the 1.26-1.28 area depending on how much horsepower the weather allows for. Between the added torque of running alcohol and 4.88 gears I think that helps tighten the gap and throws the 100 pound factor out the window. Maybe if my car was 3400 pounds instead of 2860 it may make a difference.
DrEamer
I suffer from cars on the brain!
I had to think back where I heard the whole 10 pounds equals a tenth thing, but found an old Hod Rod magazine article from 2003 that mentions it. I'm sure there are older articles, but still most likely one of many sources. Kind of a fun read anyway, since they use a Duster as a example.
https://www.hotrod.com/articles/weight-reduction/
https://www.hotrod.com/articles/weight-reduction/
j par
Well-hung Member
I've tried to have this not linear discussion a million times...
You can only imagine if you spent 35 or more years racing a-bodys that should go 17 or 16 seconds down to 14 or 13 and possibly even one 12 LOL that if I continue down this little bit of weight loss here in a little bit more horsepower there I should have no problem doing 11s or 10s... But I'm sure as anybody knows that has done 11's or 10's.... IT'S NOT LINEAR!!..
Controlling 10 or 11 second traction and suspension become exponentially as well...
318 I know you will do it.. if you're like me and you set your mind to it it's going to get done... but I assure you it's not going to be the linear results you seen in the past.. if this was the case then you could just go the opposite route and not lighten the truck and build it to do an 11-5 and then just start taking bumpers and heater box is off to lighten it up... And end up at a 10.99...
You can only imagine if you spent 35 or more years racing a-bodys that should go 17 or 16 seconds down to 14 or 13 and possibly even one 12 LOL that if I continue down this little bit of weight loss here in a little bit more horsepower there I should have no problem doing 11s or 10s... But I'm sure as anybody knows that has done 11's or 10's.... IT'S NOT LINEAR!!..
Controlling 10 or 11 second traction and suspension become exponentially as well...
318 I know you will do it.. if you're like me and you set your mind to it it's going to get done... but I assure you it's not going to be the linear results you seen in the past.. if this was the case then you could just go the opposite route and not lighten the truck and build it to do an 11-5 and then just start taking bumpers and heater box is off to lighten it up... And end up at a 10.99...
This topic wasn't about my truck, or any car in particular. Everyone keeps talking about ET slips, and the faster you go the harder it is. I know that. I knew that before some people ever made a pass at the track. My question wasn't about ET slips, it was strictly about what a 100 pounds was worth in HP. In other words, if you had two Dusters that each had a 340 and they ran identical. If one gave his buddy a ride that weighed 200 lbs, how much hp would he have to add to have his buddy feel the exact same power as the Duster feels without the buddy? The answer: Nobody here knows.. LOL, so we'll talk on traction, and 10's vs 12's, etc etc... LOL
P.S. - you still have no clue how fast (or slow LOL) I've gone, so don't pretend you do.... and no, you'll never get another ET slip from my past
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That's why I'm kind of done with this thread... LOL. Everyone is bent on ET slips, and the faster you go the harder it is and more hp it takes, and traction. I thought i made the point in my opening post that i was aware of the tenth per 100 lbs. That is why I made the question bigger lettering and underlined it. How much HP equivalency is a 100 lbs loss? LOL 
What this tells me is nobody knows how much hp I have to add to make up for a 100 lbs added. That's fine.
What this tells me is nobody knows how much hp I have to add to make up for a 100 lbs added. That's fine.
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j par
Well-hung Member
Okay what are you disagreeing with...That's why I'm kind of done with this thread... LOL. Everyone is bent on ET slips, and the faster you go the harder it is and more hp it takes, and traction. I thought i made the point in my opening post that i was aware of the tenth per 100 lbs. That is why I made the question bigger lettering and underlined it. How much HP equivalency is a 100 lbs loss? LOL
What this tells me is nobody knows how much hp I have to add to make up for a 100 lbs added. That's fine.
I said the same thing as everybody else basically and I get the disagree button...
just your general blabber about how I don't know that a 17 to 15 isn't the same as a 13 to 11 and blah blah… don't you ever get tired of typing it? Yes, everyone else is typing the same without answer the 1 question I asked. P.S. - you don't know how fast I've been so quit pretending you do. And no, I'll not post another ET slip from my past.
j par
Well-hung Member
You have countless threads on this truck LOL and are currently taking weight off the truck LOL but this isn't about your truck... LOL...
Agree, it's not JUST about my truck, it's about every car I'm working with at the moment.
j par
Well-hung Member
when you quit pretending you've went fast in a body and stop a alluding to it with no time slip to prove it...
j par
Well-hung Member
Don't worry grasshopper you'll get there...
Have fun... LOL… I got my answer, as suspected, nobody knows the answer here either.. It's ok.
j par
Well-hung Member
"when you can snatch the pebble from the Master's hand"
"When you can walk upon the rice paper without leaving a footprint"
....
"When you can walk upon the rice paper without leaving a footprint"
....
j par
Well-hung Member
If this wasn't fun I wouldn't be doing it...
There's no one answer here... most people are only going to know what works for their car because of their experience with it...
There's always a trade-off...
Take for instance trying to make a truck push through wind at 11 seconds as opposed to a duster at the same weight..
mopowers
Well-Known Member
Not sure why this is so hard to understand. Take your scenario above. If both dusters were bone stock 14 sec cars, one that was 200 lbs heavier would need about 15 hp more to be as quick as without the added 200 lbs.
Now, if the cars were both 10.5 sec cars, the added 200 lbs would need about 34 more hp to be as quick (i.e more than twice as much). Maybe an easier way to think about it as a percentage of total hp. In other words, how much more hp - in terms of percentage of the total - is needed to offset an additional 100 lbs. That answer would probably be A LOT closer to constant than the actual hp number. Because as already said - the actual hp # is NOT LINEAR! It depends on how much power you're already starting with.
yellow rose
Overnight Sensation
It's relatively easy to peel several hundred pounds off a 3600 pound car.
It's harder to get a say, 3200 pound car to 2800 pounds.
It's even worse to get cars lighter than that. That's an issue. Then, once you get into the mid 11's, you've got to add weight with safety equipment.
At some point you get the weight you get, and you build accordingly or build what you can and live with the ET.
It's as simple as that. Especially with a limited budget.
j par
Well-hung Member
Now compare that same scenario to a 74 Duster and a 1980 Dodge truck with the same weight doing 10/5...
j par
Well-hung Member
Try giving an answer to post 50?..
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