Handling Dynamics... !!

Post by **uvamosk** » Thu Feb 09, 2006 7:00 am

Here is a good question for you to all ponder..

Is it better to have a car that is light but has horable weight distrubution..

Or is it better to have a car that weights more but the weight has been shifted to the back of the car to = a 50/50 Distrubution...???

I ask becuase i was going to buy a carbonfiber hood, and hatch and so on then i got to thinking about the days when i Owned a Hatchi and how everyone tried to make them 50/50 instead of just light... So i was thinking it makes for better handling...

So that lead me to think why not just get the hood, leave the hatch move the batt. and try to keep the car even...

Post by **crzycav86** » Thu Feb 09, 2006 7:06 am

It really depends on what you're comparing.

How heavy are the cars you're comparing and what's the weight distribution for each?

Post by **Iamjohnhayes** » Thu Feb 09, 2006 7:11 am

well a light car would accellerate faster and would allow later braking, where as a 50/50 would allow for easier / more predictable car control.

also keep in mind a lot of carbon s13 hatches recomend using a new piece of rear glass that is made of a light weight acrylic. not using the acrylic can actually lead to cracking your new carbon hatch. plus that huge piece of glass is heavy

Post by **uvamosk** » Thu Feb 09, 2006 7:28 am

Im comparing the 240sx I think they are 2600 to 2700 lbs ... I want a all round handling car.. not a super light drag racer that has the tendancy to want to swing the rear end becuase its to light... lol I already have more power than i need back there trying to swing it anyway... lol O and well noted on that IamJohnhayes...

Post by **Structure240sx** » Thu Feb 09, 2006 9:10 am

totally the wrong forum for this

to make the post worth it

i doubt you will feel a difference doing any of this. you would have to entirely strip the car of everything you dont need to feel a difference. saving 50-100lbs wont be too noticeable.

Post by **nissanfanatic** » Thu Feb 09, 2006 1:53 pm

Most race cars shoot for a 40/60 weight distribution.

Ideally, I'd like to be around 45/55. It encourages the car to oversteer a little.

http://en.wikipedia.org/wiki/H...ution

Post by **Nismo_Freak** » Thu Feb 09, 2006 2:08 pm

nissanfanatic wrote:Most race cars shoot for a 40/60 weight distribution.

Ideally, I'd like to be around 45/55. It encourages the car to oversteer a little.

http://en.wikipedia.org/wiki/H...ution

Weight distribution is not communicable in terms of chassis tuning.

Something that has a short wheelbase will want a more centralized weight, whereas a longer wheelbase car may opt for greater polarity or possibly an uneven weight distribution.

Within a 240, you will think you are doing alot of rear end weight removal when in actuality there is more weight to be lost in the front of the car. Use the driver as the polar center of the car. Anything in front of you is forward weight, and anything behind you is rear weight.

Typically when removing weight from the car you want to remove it from the extremities the most. Extremities being the highest or furthest points on the car (bumpers, hoods, roof, etc.). This weight has the most effect on handling and weight transfer in general. Reducing the polar momentum will net better feel than will removing alot of "dead" weight. Consider items on the interior of the car as dead weight, as are sway bars, exhausts, etc. Reducing the weight of these items has little to do with the handling of the car. They are either well distributed (exhaust, carpet, etc.) or they are below the center of gravity (sway bars, etc.).

In terms of acceleratory force, you want to reduce the amount of mass that is accelerated. Items that are final in relation to force multiplication (chassis, hoods, etc.) are the last place to start. The best place to start is at the flywheel and work your way back.

Reducing the weight of the car negates certain popular modifications such as 300ZX brakes and big wheels and tires, both of which add alot of unsprung, rotational weight which is the worst form of weight, and the tires typically drop the torque multiplication.

Dropping alot of weight here and there will net a faster car, but you will make a car that is less stable and harder to drive. It might be physically faster, but in the hands of an unexperienced or unadaptive driver it can be slower.

Post by **uvamosk** » Thu Feb 09, 2006 2:31 pm

So with that read, I can say that in a 240sx I will want to do hood, hatch, rear seats, internal panles. But by adding the 5lugs, big breaks ill make up for that loss weight but Ill be able to even the car out. Which for me is kinda what i wan.

Post by **WDRacing** » Thu Feb 09, 2006 3:19 pm

Wrong forum entirely...but thanks for the explanation Alan.

Post by **onosqv** » Tue Feb 14, 2006 1:38 pm

If you are really anal, once you remove the crap out... you corner weigh & balance w/ dual adjustable coilovers... which will allow you to get as close as possible to watever weight you wish (statically of course).

Post by **cardinal** » Wed Feb 15, 2006 5:12 pm

uvamosk wrote:Im comparing the 240sx I think they are 2600 to 2700 lbs ... I want a all round handling car.. not a super light drag racer that has the tendancy to want to swing the rear end becuase its to light... lol I already have more power than i need back there trying to swing it anyway... lol O and well noted on that IamJohnhayes...

2700 might be a little on the high side, but if you have a bunch on non essentials in the car they will add up fast.

I have a 92 s13 with a custom eight point cage (kirk racing), SR etc all metal body and it came in at 2551 lbs with a full tank of fuel. The cross weight with driver (170lbs) was at 50% and it has a 52/48 weight distribution. I am going to relocate the battery to the rear which might help a little with that, but not to much. Keep in mind this is a track only car - completely stripped down etc. It takes a while to get all of the sound insulation etc. out but if you want a lean 240 then it is a must.

Post by **Joe** » Thu Feb 16, 2006 5:46 am

Cardinal, how do you like your kirk racing cage? was it a kit cage from them or did they actually build it for you?

Post by **91rs13** » Thu Feb 16, 2006 10:02 am

Kamin wrote:Cardinal, how do you like your kirk racing cage? was it a kit cage from them or did they actually build it for you?

When did Kirk start making one for the S13?

Post by **cardinal** » Thu Feb 16, 2006 3:55 pm

It was a complete custom job. Mark is really good over there. I don't put much faith in any bolt in cage once you get a custom job. Way safer (had NASCAR bars put in) and talk about a stiff chasis - there is no flex in it now!

Post by **nismofly** » Thu Feb 16, 2006 7:45 pm

built to any set of sanctioning body rules or just custom?

im going to need a reputable cage builder for my NASA car, i would drive to Atlanta if he could do one for me, since i havent found anyone closer yet

Post by **cardinal** » Fri Feb 17, 2006 6:01 am

It was built to meet SCCA rules. These are way more strict than NASA, just like the SCCA. He is located in Alabama. Going to cost 1500-2300 dollars if you want it done right.

Post by **uvamosk** » Wed Feb 22, 2006 8:13 am

Is a half cage worth it or not... I was going to have one put in from behind the driver back to add a little weight to the back plush help with body flex? but I also wanted to so i could have something to mount seatbelts too...

Post by **nismofly** » Wed Feb 22, 2006 8:26 am

you mean just like a 4 point roll bar?

this would actually be better if youre driving on the street

Post by **onosqv** » Wed Feb 22, 2006 9:22 am

uvamosk wrote:Is a half cage worth it or not... I was going to have one put in from behind the driver back to add a little weight to the back plush help with body flex? but I also wanted to so i could have something to mount seatbelts too...

Well, check this out:

autopower roll bar in crash

I'm not sure where everything will be positioned in a 240, but it's definately worth a look into especially if you 90% of the time you are daily driving.

Post by **InsanityInc** » Wed Feb 22, 2006 2:51 pm

To answer the original question, I'd take the heavier car. Weight has little effect on straight up handling (so long as your tires are up to the task), it has a tertiary effect on handling in terms of braking distance though, but better distribution definitely plays a large role.

Post by **Nismo_Freak** » Tue Mar 14, 2006 2:00 pm

InsanityInc wrote:To answer the original question, I'd take the heavier car. Weight has little effect on straight up handling (so long as your tires are up to the task), it has a tertiary effect on handling in terms of braking distance though, but better distribution definitely plays a large role.

Completely wrong.

I've argued once, and I will not argue again.

There is a reason why every single form of racing looks to shave every gram of weight off the car as deemed legal in the regulations.

Post by **Dano** » Wed Mar 15, 2006 8:38 am

Nismo_Freak wrote:
There is a reason why every single form of racing looks to shave every gram of weight off the car as deemed legal in the regulations.

The less weight, the less stress all components have to endure...

And stop arguing with Alan on this issue, your wrong.

-Dan

Post by **uvamosk** » Thu Mar 16, 2006 1:40 pm

Hey, So I have another question Should I really drop the money for a full coilover suspension or run on a stock and spring ? setup... the car is a street car with Autox / drift asperations... If anyone can give me some input it will be my daily driver... but I want it to be a nice handling car...

Post by **Nismo_Freak** » Sun Mar 19, 2006 10:46 am

Coilovers are the only way to go if you want a good handling car. You can spend about the same amount of money on buying a comparable spring/shock combo and all that jazz and still not have height adjustability. Height adjustability opens the door for corner balancing, and other handling adjustements.

As far as a daily driver and ride quality. You'll get used to the coilovers, and honestly it's not that bad. If you care about ride quality then you can always ride along in someones car before buying.

Post by **uvamosk** » Sun Mar 19, 2006 2:13 pm

Thank you for the help so Coilovers it is!!!! thank you

Post by **madbouncy** » Tue May 02, 2006 9:54 am

I'd rather have the heavier car with better weight distribution as long as it's somewhat where I want it. If you're only moving weight to the rear than I'll take the lighter car though.

Shaving weight will put less stress on componets but most are designed well enough that the small weight he's changing won't make a huge difference since it's all body. In racing if they remove weight they get to put it where they want since most have met min weight already. If your entire car is light and you make the... completely forgot the right name, but the bottom of the car when it's completely sealed. Just make that really heavy to lower your center of gravity. If the weight has to be on there it might as well help you out.

If you know where the weight is on the car when you buy all your suspension parts, you can help compensate for it. Worse comes to worse just stick to running only clockwise or counter, depending on which side your car favors. Nothing wrong with having a left or right biased car for road racing as long as you know what you're going into.

Post by **sr20goofus** » Wed May 03, 2006 2:44 am

madbouncy wrote: Worse comes to worse just stick to running only clockwise or counter, depending on which side your car favors. Nothing wrong with having a left or right biased car for road racing as long as you know what you're going into.

where is the fun in that kind of racing? i know NASCAR is very competative and big bucks and all that, but i would much rather do a road course than a circuit loop.

Light weight directly affects handling, less weight on the suspension in general means less stress put on all components in any turn which means faster/better reacting suspension. I wouldnt neccessarily take the heavier car, but i would take the car that has the bigger market for suspension components so there wont have to be any custom work and to keep things to a lower budget. My car is prepped enough to be race ready, but i can still lose another 100lbs i think but then my cage will gain all that weight back. and ill be around 2350-2400 1/2 tank with cage. (i already weigh 2350 no cage and much room for weight loss with keeping metal bumpers and all metal panels)

I am not running coilovers because the KYB's and Tein springs still have enough potential on my car to bring my lap times down a bit more, then ill upgrade after a few more events. If you want the coner balance adjustabliity and a 50/50 distribution, go with the car with a larger market, itll be easier to get what you want, with out too much sacrifice.

Post by **madbouncy** » Fri May 05, 2006 1:03 pm

I was talking about road courses, not circle tracks. Also, aftermarket won't really matter since he's just thinking about which way to go on the same car.

Post by **sr20goofus** » Fri May 05, 2006 5:12 pm

if its all ont eh same car then go both ways to haev the best setup....reduce the overall weight and adjust battery location to help achieve 50/50 weight distribution. And when your done you will have a well balanced car that is light weight, which is the race car ideal.

Post by **Bubba1** » Sun May 07, 2006 12:31 am

uvamosk wrote:Here is a good question for you to all ponder..

Is it better to have a car that is light but has horable weight distrubution..

Or is it better to have a car that weights more but the weight has been shifted to the back of the car to = a 50/50 Distrubution...???

I ask becuase i was going to buy a carbonfiber hood, and hatch and so on then i got to thinking about the days when i Owned a Hatchi and how everyone tried to make them 50/50 instead of just light... So i was thinking it makes for better handling...

So that lead me to think why not just get the hood, leave the hatch move the batt. and try to keep the car even...

Correct answer is it depends on the car, but in the end, it really doesn't matter much. It's how you handle the car that's more relevant than it's weight distribution. On a street car, buying 2 aftermarket carbon fiber bits is more of a style statement than anything else. Handling improvements from their use will be about as dramatic as installing a type R sticker or silly window banner. If you like the look of Carbon fiber hoods, then that should be your motivation to buy it. If you really want to see a real improvement in your car's handling, there are more other more effective (but less visual) things to do, including improving your driving skills (professional instruction), or upgrading tires/brakes. Suspension work too, of course.

Handling Dynamics... !!

Handling Dynamics... !!

Re: Handling Dynamics... !! (uvamosk)

Re: Handling Dynamics... !! (crzycav86)

Re: (nissanfanatic)

Re: Handling Dynamics... !! (uvamosk)

Re: (uvamosk)

Re: (cardinal)

Re: (Kamin)

Re: (Kamin)

Re: (nismofly)

Re: (uvamosk)

Re: (InsanityInc)

Re: (Nismo_Freak)

Re: (uvamosk)

Re: (madbouncy)

Re: (sr20goofus)

Re: (madbouncy)

Re: Handling Dynamics... !! (uvamosk)

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