Write-up: How to determine approx. HP gains from removing weight! - Page 3 - Focus Fanatics
Ford Focus Forum
HomeContact UsAbout UsGalleryDiscussion ForumsMarketplace


Go Back   Focus Fanatics > Ford Focus Discussions > Ford Focus & General Car Chat

Ford Focus & General Car Chat Discussion Forum relating to nonspecific Ford Focus models, car purchasing, auto industry news and any car talk.

Search This Forum | Image Search | Advanced Search    
Ford Focus Tire & Wheels FocusFanatics Merchandise

Reply
 
Thread Tools Display Modes
Old 08-12-2005, 12:41 PM   #21
Taiden
Focus Enthusiast
 
Join Date: Aug 2005
Fan#: 26198
Location: Portland, Maine
What I Drive: 94 Grand Cherokee 55k mi, standard

Posts: 65
FF Reputation: 1 Taiden Good Standing Member
Buy-Sell-Trade Rating: (0)
Quote:
Originally posted by fokuzx3
did i do something wrong?


The Corral - Horsepower Estimator

Your trapspeed was 90 miles per hour
and your vehicle weight was 2798 pounds.

You are making 223203 hp.


That's funny.
__________________
I doubt anyone on a Focus board would be interested, but I'm selling a '94 Jeep Grand Cherokee with 55k miles, all power options and a manual tranny. PM for details. :)
Taiden is offline  
    Reply With Quote
Sponsored Links
Advertisement
 
Old 08-12-2005, 03:50 PM   #22
SVTkonig
Focus Enthusiast
 
SVTkonig's Avatar
 
Join Date: Feb 2005
Fan#: 18768
Location: Beaverton, Oregon
What I Drive: 2002 CD Silver SVT 2 door

Posts: 367
FF Reputation: 1 SVTkonig Good Standing Member
Buy-Sell-Trade Rating: (1)
rotational mass of the wheels only matters for the front two wheels. the rear wheels are considered sprung mass because they're just along for the ride so to speak. sprung mass is silly for the quarter mile unless you're talking hundreths of a second.
__________________
SVT squad # 108

Here's what mommy should have told you to do when you downshift:
1. Step on the clutch
2. Simultaneously slide the shifter into a lower gear and give the throttle a quick, amazingly precise jab to rev the engine to exactly the rpm it needs to be at in the next gear
3. Quickly let out the clutch

Oh sure, It takes a few thousand tries before you get the timing and precision of your jab just right, but the reward is that you no longer suck.
SVTkonig is offline  
    Reply With Quote
Old 08-12-2005, 04:04 PM   #23
Taiden
Focus Enthusiast
 
Join Date: Aug 2005
Fan#: 26198
Location: Portland, Maine
What I Drive: 94 Grand Cherokee 55k mi, standard

Posts: 65
FF Reputation: 1 Taiden Good Standing Member
Buy-Sell-Trade Rating: (0)
Quote:
Originally posted by SVTkonig
rotational mass of the wheels only matters for the front two wheels. the rear wheels are considered sprung mass because they're just along for the ride so to speak. sprung mass is silly for the quarter mile unless you're talking hundreths of a second.
Hmm. The front wheels and the rear wheels are technically connected through the road surface, so I would say rear wheels are considered unsprung mass unless this has already been established elsewhere.

Ideas?
__________________
I doubt anyone on a Focus board would be interested, but I'm selling a '94 Jeep Grand Cherokee with 55k miles, all power options and a manual tranny. PM for details. :)
Taiden is offline  
    Reply With Quote
Old 08-12-2005, 04:15 PM   #24
Carrera26
Focus Fanatic
 
Carrera26's Avatar
 
Join Date: Aug 2004
Fan#: 12237
Location: Gainesville, FL
What I Drive: 2005 Mazda3 2.3/2003 VW Passat GLX

Posts: 2,957
FF Reputation: 2 Carrera26 Good Standing Member
Buy-Sell-Trade Rating: (0)
Considering straight-line acceleration you are still working with the rotational inertia of the rear wheels, even though they are not powered. It would be like dragging a large hoop. The heavier one would still be harder to get moving and accelerate with than a lighter one of the same dimension.

It makes MUCH less difference on the undriven wheels than on the driven wheels in this scenario, but it still applies full force for braking and handling situations.

Also, the test vehicle that yielded the ratio was a 2wd vehicle, so the 3:1 ratio still applies regardless.
__________________
Don't waste another minute waiting on parts, or anything else. Just get out there and start racing! You will suck at first, and you will be slower than many other cars, but the only thing you will regret is not starting earlier...
Carrera26 is offline  
    Reply With Quote
Old 08-12-2005, 09:17 PM   #25
xFOCIx
Focus Enthusiast
 
Join Date: May 2005
Fan#: 23553
Location: Oregon, OR
What I Drive: 2005 ZX3 5spd

Posts: 527
FF Reputation: 15 xFOCIx Great Standing Member
Buy-Sell-Trade Rating: (0)
To call it "hp gain equivalent" is incorrect scientifically and in real life overall performance.

The specific weight is decreased as a function of Δm where power is a constant.
ΔV/Δt is all about specific power, but not so for top speed. Weight is a factor because rolling resistance is a constant x load, but when it comes to top speed, rolling resistance is a distant second to air drag, so reduction in weight to yield specific power comparable to increasing 25hp will not get you the top speed of 25 real hp gain.
xFOCIx is offline  
    Reply With Quote
Old 08-12-2005, 09:22 PM   #26
xFOCIx
Focus Enthusiast
 
Join Date: May 2005
Fan#: 23553
Location: Oregon, OR
What I Drive: 2005 ZX3 5spd

Posts: 527
FF Reputation: 15 xFOCIx Great Standing Member
Buy-Sell-Trade Rating: (0)
Quote:
Originally posted by SVTkonig
rotational mass of the wheels only matters for the front two wheels. the rear wheels are considered sprung mass because they're just along for the ride so to speak. sprung mass is silly for the quarter mile unless you're talking hundreths of a second.
You're wrong. Anything that must be spun up is a rotation mass(flywheel, brake rotors, transmission parts etc). The way mass is distributed matters as well, because it affects rotational momentum.
xFOCIx is offline  
    Reply With Quote
Old 08-12-2005, 09:29 PM   #27
xFOCIx
Focus Enthusiast
 
Join Date: May 2005
Fan#: 23553
Location: Oregon, OR
What I Drive: 2005 ZX3 5spd

Posts: 527
FF Reputation: 15 xFOCIx Great Standing Member
Buy-Sell-Trade Rating: (0)
Quote:
Originally posted by Carrera26
I've heard that you can make 223203 BHP with this chip you can get off of Ebay...
hp applies to braking too. Horsepower is basically drag + change in kinetic energy over time.

When you crash into a tree, an instantaneous rate of acceleration of -490m/s^2 is possible for a very short amount of time and the "peak" hp can easily be 10,000 hp ;)
xFOCIx is offline  
    Reply With Quote
Old 08-12-2005, 10:39 PM   #28
Taiden
Focus Enthusiast
 
Join Date: Aug 2005
Fan#: 26198
Location: Portland, Maine
What I Drive: 94 Grand Cherokee 55k mi, standard

Posts: 65
FF Reputation: 1 Taiden Good Standing Member
Buy-Sell-Trade Rating: (0)
Quote:
Originally posted by itsme
To call it "hp gain equivalent" is incorrect scientifically and in real life overall performance.

The specific weight is decreased as a function of Δm where power is a constant.
ΔV/Δt is all about specific power, but not so for top speed. Weight is a factor because rolling resistance is a constant x load, but when it comes to top speed, rolling resistance is a distant second to air drag, so reduction in weight to yield specific power comparable to increasing 25hp will not get you the top speed of 25 real hp gain.
I'm going to say that this isn't applicable, because top speed isn't concerned, only top acceleration. Top speed is mostly effected by an unflashed ECU, so I don't understand why it would be discussed in the first place.
__________________
I doubt anyone on a Focus board would be interested, but I'm selling a '94 Jeep Grand Cherokee with 55k miles, all power options and a manual tranny. PM for details. :)
Taiden is offline  
    Reply With Quote
Old 08-13-2005, 12:23 AM   #29
Karniv04
Focus Enthusiast
 
Karniv04's Avatar
 
Join Date: Mar 2005
Fan#: 20353
Location: Carrollton, TX
What I Drive: 2004 Pitch Black SVT Coupe

Posts: 298
FF Reputation: 2 Karniv04 Good Standing Member
Buy-Sell-Trade Rating: (1)
Unrotational sprung weight mass equivalent to the ratio of 312:42139 is applicable to the gains of non horsepower drivetrain increase. Now when you take a look at the acceleration equation of 12^mn-bc/3 you can see the results between the differential locations of non powered flywheel. Who knows what capable?
__________________
2004 Pitch Black SVT

R.I.P. 2005 Liquid Grey ST
Karniv04 is offline  
    Reply With Quote
Old 08-13-2005, 11:25 AM   #30
Carrera26
Focus Fanatic
 
Carrera26's Avatar
 
Join Date: Aug 2004
Fan#: 12237
Location: Gainesville, FL
What I Drive: 2005 Mazda3 2.3/2003 VW Passat GLX

Posts: 2,957
FF Reputation: 2 Carrera26 Good Standing Member
Buy-Sell-Trade Rating: (0)
All weight loss gets progressively less important as speed increases though. The increase of performance is directly related to the rate of acceleration. So in 1st gear, say, the improvement is going to be the most prevalent, because the rate of acceleration is the highest. It will drop seriously in each higher gear.

Like with a flywheel, accelerating it from 1000 to 7000 rpm in 3 seconds in 1st gear is going to show much more effect than the acceleration from 5000 to 7000 RPM in 4 seconds in 2nd gear.
__________________
Don't waste another minute waiting on parts, or anything else. Just get out there and start racing! You will suck at first, and you will be slower than many other cars, but the only thing you will regret is not starting earlier...
Carrera26 is offline  
    Reply With Quote
Reply

Bookmarks & Social Networks
-->
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 10:38 PM.


Copyright 2002-2014 FocusFanatics.com. All Rights Reserved : Terms of Use : Privacy Policy : Advertise Information

Focus Fanatics Ford Focus Forum offers many fun ways for you to engage with other Ford Focus Owners from across the world. Whether it be about the aftermarket performance modifications, technical how-to's, European tuned suspension or awesome fuel economy similar to the Acura TLX or Fiesta ST. You can find all Ford Focus and Focus ST related information here. Join our Ford Focus discussion forums and chat with local Focus enthusiasts in your area.