HP/Weight Question

Let's assume that you had a car that weighs 3000 lbs and runs 5.00 in the 1/8 mile. If you added 150 lbs to that car how much more hp would it take to make it still run 5.00? Trying to gather some data for an argument.

Joe acording to wallace it take 1247 hp @ 3000 to run 5.00 and it takes 1276 hp to run 5.00 @ 3150 I do not know how accurate that is but it should give you some idea....


Randy

there is no way it would take another 29 hp to run the same time at those weights and expecially at those times i would say you would need atleast 125hp -175hp more to run the same time at that level .

good luck on the argument Joe

Bruno if you think it is wrong please call Wallace and chew his ass and tell him it isn't right, then you can give him the formula for making it right.....or explain why you know it is wrong, but I would make sure you have a clue before you do it.......


Randy

the Coug wrote:Bruno if you think it is wrong please call Wallace and chew his ass and tell him it isn't right, then you can give him the formula for making it right.....or explain why you know it is wrong, but I would make sure you have a clue before you do it.......


Randy

Randy im not chewing any one out ...but i just did go to the wallace site and it said i need atleast 75hp to achieve the same times with the added weight

and it also depends on the other party's involved w/ Joe's argument ...... is this 5.0 car running a small tire?, is he ramping in the power ? it might take alot more power to run those same kinda of times at that level

and you right Randy i dont know exactly what it take sto run those numbers , but i sure as hell know it aint 29hp ..... thats just wrong !!!

FWIW...I have a friend of mine that added 120# (3 bags of salt...lol) into the trunk of a 10.5 car in an attempt to slow the car down...he actually picked up about .07-.08 due to the fact he was able to hook it better.
So, there is something to consider about where the weight is placed as well.

Bruno all I know is thats what it said when I put the numbers in.....they may have a couple different calculators for different specks and they may be off from each other, but Who knows?


Randy

Here is the deal. A car in my class has a 700 ci plus E headed motor and has ran a best of 5.04 at 141. He gets to weigh 2900 this year. I have the 815 hemi and my best so far has been 5.15 at 143. This year I have to weigh 3050 and have been warned that if I go fast I will get weight added. As a matter of fact, last year the rules guy told me that he was just waiting for me to make a good pass so he could add weight. The guy with the E headed motor has complained about my combination since day one.

joe if they do add weight make sure you put it in the rear.....

Randy

Sorry to hear they are trying to get after you like that Joe. Build a better mousetrap and the mice start getting nervous. I say if you are willing to spend the time, effort and cash to build and develop something as nice as what you have, let it run and let the others build to the same level. They can do it if they quit whining and start working at it.

Joe ,I just checked it on the one I use. It says at 3000 it takes 1249.47 to run 5.00, and at 3150 it takes 1311.97 to go 5.00..That's 62.47 which I think would be closer to reality

65-75 hp...........rule of thumb is 25 hp per 50lbs at the 3000lb level.......

Joe as far as power I don't think you have anything to worry about. From talking to you and seeing the videos your problem is getting it to the track. Extra weight may not hurt you if you can bring your timing in sooner and start making bigger HP sooner. Wish I had your problem!

Treeyasoon wrote:FWIW...I have a friend of mine that added 120# (3 bags of salt...lol) into the trunk of a 10.5 car in an attempt to slow the car down...he actually picked up about .07-.08 due to the fact he was able to hook it better.
So, there is something to consider about where the weight is placed as well.

That is a good point, it is possible the car might be faster with the added ballast. Never really know what will happen until you test.

Since you won't know for sure where the "best" place for the added ballast is until you do some testing, I would place many mounts for the ballast at several points on the car, not just in the back. It is possible that the best place for the extra weight might fall somewhere between the I/C & the rear bumper. Or crazy as it sounds, sometimes it might want to be placed closer to the nose, just depends on the car/combo.

Only testing will tell for sure.

If you have it turned down that little bit of weight wont make much diff IMO.

Besides, just go fast enough to beat the crybaby.................put the smackdown on that candy ass.

I know it's not your job to school us, but I would really be interested in your test results if you do them.

This is a good subject.

Generally, weight added between the polar moment of inertia and the rear axle, such as in the back seat area, will give an instant hit and provide a quicker reation time. Then weight added between the rear axle and the back bumper, will not give an instant hit, but the hit will last longer and may help in case you are blowing the tires off after the first couple of slick rotations. There is an experiment that you can do in order to prove this for yourself, it involves an egg carton (dozen) and four eggs. (But it's too hard to explain.)

Charlie

richter69 wrote:Besides, just go fast enough to beat the crybaby..................

Hell yea, don't show your whole hand. Save some back in case they add even more weight to you in the future. No shame in sand bagging now if the "powers that be" are foaming at the mouth just itching to stack more weight on you if you go too fast.

Sounds like the damned Pro Stock weight factoring battles all over again.

c.evans wrote:Generally, weight added between the polar moment of inertia and the rear axle, such as in the back seat area, will give an instant hit and provide a quicker reation time. Then weight added between the rear axle and the back bumper, will not give an instant hit, but the hit will last longer and may help in case you are blowing the tires off after the first couple of slick rotations. There is an experiment that you can do in order to prove this for yourself, it involves an egg carton (dozen) and four eggs. (But it's too hard to explain.)

Charlie

Is this the deal about the bi-polar polar bear that layed a dozen eggs ?

Joe, You have a problem i'm sure any of us would like to also have. beat their a$$es at their own game. That deal sounds like the Chevy guy's at the Truck pulls

Lem Evans wrote:

c.evans wrote:Generally, weight added between the polar moment of inertia and the rear axle, such as in the back seat area, will give an instant hit and provide a quicker reation time. Then weight added between the rear axle and the back bumper, will not give an instant hit, but the hit will last longer and may help in case you are blowing the tires off after the first couple of slick rotations. There is an experiment that you can do in order to prove this for yourself, it involves an egg carton (dozen) and four eggs. (But it's too hard to explain.)

Charlie

Is this the deal about the bi-polar polar bear that layed a dozen eggs ?

but the real ? is did thay tast like chicken or bear.

It seems it's all about the "hit"

jmayabb wrote:Here is the deal. A car in my class has a 700 ci plus E headed motor and has ran a best of 5.04 at 141. He gets to weigh 2900 this year. I have the 815 hemi and my best so far has been 5.15 at 143. This year I have to weigh 3050 and have been warned that if I go fast I will get weight added. As a matter of fact, last year the rules guy told me that he was just waiting for me to make a good pass so he could add weight. The guy with the E headed motor has complained about my combination since day one.

A 700 c.i.d E-460 headed engine is scared?. That is screwed up!.