CP Physicists, Mathmaticians, Engineers, Car Guys... lend me your knowledge

[pr_capone]

I am looking to make an upgrade to my car. In order to still be within the class I intend to compete in, I can make very few modifications to the car. There are two that I am currently contemplating and am wondering about bang for the buck.

Option 1: I am considering shedding 3.2 lb of unsprung weight from all 4 corners of the car. It makes sense to me that a heavier wheel would take longer to slow down. The opposite should also be true meaning better breaking and acceleration. So, is a 3.2lb loss per wheel going to give me a significant gain?

I understand that every pound of rotational weight roughly equals 8lb of static weight. Lighter wheels will also allow the suspension to have an easier time of keeping rubber on the road giving me a greater point of contact which means better grip.

Option 2: Replace the stock (which is actually pretty good as is) suspension with coilovers which will allow me to adjust ride height and should damn near eliminate any body roll.

This will give me a much more firm ride and a lower center of gravity which means I should be able to go through turns faster than what I am able to right now.

----

Both of these options would still keep me in "Stock" class and there is a minor money difference between the two. Can anyone here give me a reason to go with one above the other?

[SAUTO]

I am looking to make an upgrade to my car. In order to still be within the class I intend to compete in, I can make very few modifications to the car. There are two that I am currently contemplating and am wondering about bang for the buck.

Option 1: I am considering shedding 3.2 lb of unsprung weight from all 4 corners of the car. It makes sense to me that a heavier wheel would take longer to slow down. The opposite should also be true meaning better breaking and acceleration. So, is a 3.2lb loss per wheel going to give me a significant gain?

I understand that every pound of rotational weight roughly equals 8lb of static weight. Lighter wheels will also allow the suspension to have an easier time of keeping rubber on the road giving me a greater point of contact which means better grip.

Option 2: Replace the stock (which is actually pretty good as is) suspension with coilovers which will allow me to adjust ride height and should damn near eliminate any body roll.

This will give me a much more firm ride and a lower center of gravity which means I should be able to go through turns faster than what I am able to right now.

----

Both of these options would still keep me in "Stock" class and there is a minor money difference between the two. Can anyone here give me a reason to go with one above the other?

what does the weight of the wheel have to do with something breaking?






i keed i keed.

[SAUTO]

i will say that a couple of years ago i put adjustable coil overs on an impreza and its sitting here at the shop as we speak having adjustable KYP struts and eibach springs installed.

he absolutely hated the coil overs.


why? i couldnt say, didnt think to ask.


but its a pretty bad ass car.

[Fish]

Why would you be worried about ~13lbs of weight on a ~3000lb vehicle?

[BigMeatballDave]

Muffler bearings and Floorboard gaskets

[SAUTO]

i will say that the best thing he did for body roll was some body stiffening bars that bolt up at the strut towers front and rear.

[loochy]

You might feel a slight difference from the wheels, but it won't be a significant amount.

[pr_capone]

Why would you be worried about ~13lbs of weight on a ~3000lb vehicle?

rotational weight. we are actually talking about over 100lb of effective weight loss... among other gains.

[pr_capone]

i will say that the best thing he did for body roll was some body stiffening bars that bolt up at the strut towers front and rear.

can't do that and remain in stock class :(

[prhom]

The lighter wheels will help acceleration, though I'm not sure if it would be a difference you could actually feel.

I've heard that beefing up your brakes is the best change you can make to a stock vehicle since most stock brakes are undersized for the vehicle weight. Maybe that's not allowed by the category you race in though?

[pr_capone]

The lighter wheels will help acceleration, though I'm not sure if it would be a difference you could actually feel.

I've heard that beefing up your brakes is the best change you can make to a stock vehicle since most stock brakes are undersized for the vehicle weight. Maybe that's not allowed by the category you race in though?

because my car is an SVT, it already has bigger brakes. I will be getting some better pads though.

[Sofa King]

You should probably drop off one of the fat chicks at her parent's house. She's probably not drunk anymore anyways.


That should help you shed 400-500 lbs.

[Ace Gunner]

might turn faster.. shedding weight helps the car for sure.

quality shocks paired with upgraded coil springs up front are what make the diff. what kind of car?

[pr_capone]

might turn faster.. shedding weight helps the car for sure.

quality shocks paired with upgraded coil springs up front are what make the diff. what kind of car?

03 Ford Focus SVT

[Ace Gunner]

oh I like those cars. what kind of competition?

[pr_capone]

oh I like those cars. what kind of competition?

SCCA Autocross

[Time's Yours]

Auto cross or road course?

edit: nevermind, posted at the same time

[Time's Yours]

For autocross I'd say coilovers without question.

However, I'm assuming you also use the car for at least some transportation or you'd be doing road course.

Taking that into consideration, you can do the wheels and still keep the comfort of your stock suspension.

Are you sure you can only drop 3.2 lb per corner with wheels/tires?

[pr_capone]

For autocross I'd say coilovers without question.

However, I'm assuming you also use the car for at least some transportation or you'd be doing road course.

Taking that into consideration, you can do the wheels and still keep the comfort of your stock suspension.

Are you sure you can only drop 3.2 lb per corner with wheels/tires?

The stock wheels on the car weigh 21lb. The lightest wheel I can find that fits the car 17.8lb.

You are correct in that it is my daily driver but we have another car for family stuff so its typically just me in the car and I would not be overly bothered to have stiffer suspension.

[ModSocks]

Fun.

Honestly? Tires, tires and more Tires.

A high quality performance tire will yield far better benefits than simply getting a lighter wheel.

After that, then the shock and spring. Coil-Overs are only better than a a standard strut set up if you know how to adjust them properly. If you don't plan on having a well trained technician adjusting them, it's possible to actually lose performance and prematurely wear your tires.

For My birdie, I went with a Re-valved Bilstein with a Sam Strano (He's a F-body specialst) coil. SIGNIFICANT difference over stock.

[ModSocks]

I'm sticking by it. Coil-Overs are nice and all when well tuned....but You just can't go wrong with a great set of tires.

[pr_capone]

Fun.

Honestly? Tires, tires and more Tires.

A high quality performance tire will yield far better benefits than simply getting a lighter wheel.

After that, then the shock and spring. Coil-Overs are only better than a a standard strut set up if you know how to adjust them properly. If you don't plan on having a well trained technician adjusting them, it's possible to actually lose performance and prematurely wear your tires.

For My birdie, I went with a Re-valved Bilstein with a Sam Strano (He's a F-body specialst) coil. SIGNIFICANT difference over stock.

I already did the tires. Running Continental DWS Extreme Contact.

I would be having a local tech adjust and tune the coilovers if that is the way I wind up going.

[Ace Gunner]

okay, well ya, I would look into aftermarket springs and find the stiffest pairing available. load adjusting isn't where you'll get any significant improvements and that shit adds weight. FWD is all about that front set of tires, the back are ballast pretty much just dragging along for the ride. strong wheels and hefty suspension up front. by changing out those springs/shocks you aren't adding weight.

[KC native]

Coil overs IMO. The added speed you can carry into and out of corners would outweigh the small gains from lightening up the wheel.

[veist]

can't do that and remain in stock class :(

You're not allowed to mess with the front sway bars?

[ModSocks]

I already did the tires. Running Continental DWS Extreme Contact.

I would be having a local tech adjust and tune the coilovers if that is the way I wind up going.

Well then there ya go, Coil-Overs it is compadre.

Anything you can do to reduce the understeer that FWD cars are notorious for.

[Ace Gunner]

Fun.

Honestly? Tires, tires and more Tires.

A high quality performance tire will yield far better benefits than simply getting a lighter wheel.

After that, then the shock and spring. Coil-Overs are only better than a a standard strut set up if you know how to adjust them properly. If you don't plan on having a well trained technician adjusting them, it's possible to actually lose performance and prematurely wear your tires.

For My birdie, I went with a Re-valved Bilstein with a Sam Strano (He's a F-body specialst) coil. SIGNIFICANT difference over stock.

yep -- tires tires tires is the quickest most profound improvement.

[ModSocks]

The stock wheels on the car weigh 21lb. The lightest wheel I can find that fits the car 17.8lb.

You are correct in that it is my daily driver but we have another car for family stuff so its typically just me in the car and I would not be overly bothered to have stiffer suspension.

Have you checked out those Carbon Fiber wheels? I have no idea what your budget is, But you probably can't get much lighter than a Carbon Fiber/Kevlar wheel. And they look bad ass too.

I saw some at SEMA....can't remember the name of the company ATM....But they're expensive as fuck IIRC.

[pr_capone]

Have you checked out those Carbon Fiber wheels? I have no idea what your budget is, But you probably can't get much lighter than a Carbon Fiber/Kevlar wheel. And they look bad ass too.

I saw some at SEMA....can't remember the name of the company ATM....But they're expensive as **** IIRC.

I've scoured the net for a 17x7 carbon fiber wheel that fits my car... not finding a damn thing. Will continue looking though.

[The Dawg]

Can you do any performance mods without losing your stock status? Honestly I think your suspension should be in OK shape. I'd look too add a little more HP if possible.

[themanwithnoname]

Can you go down in size of the wheels? For a car like that, I'd want to buy a second set of wheels, go smaller and a bit wider, at least in the front if possible, and slap on some super grippy tires that you won't run on the street (don't have to be non street legal, just ones you'd only run when doing this). Don't forget you'll need to clear the brakes too.

I would think suspension work and tuning would have a bigger impact though.

[jspchief]

I bet you are gonna get some real top notch advice here.

[loochy]

U SHUD GET NITRIS BECUZ IT MAKES FIRE COME OUT OF YOUR EXHAUST AND ITS LIKE A JET ENGINE FOR YOUR CAR ITS LIKE THE BATMOBILE AND THEN YOU CAN DO IT WITH CATWOMAN

[El Jefe]

03 Ford Focus SVT

Lol.

[Okie_Apparition]

I'd build a ramp

[MIAdragon]

Lol.

Did he make a funny?

[pr_capone]

Lol.

Why is that funny?

[FRCDFED]

I'm adding weight:)

[El Jefe]

Why is that funny?

Those things suck, no offense. We build high performance transmission for those things, not a ton, but probably 5+ a year. We see some very high horepower SVT's, the juice isn't worth the squeeze in my opinion.

[El Jefe]

Why is that funny?

I should clarify, I wasn't laughing at you, I was laughing at your car. All the non-ricer kids buy them and then turn them into ricers.

[Time's Yours]

Those things suck, no offense. We build high performance transmission for those things, not a ton, but probably 5+ a year. We see some very high horepower SVT's, the juice isn't worth the squeeze in my opinion.

Who cares? He's autocrossing it in a stock class, not spending a ton of money trying to make it a race car.

[pr_capone]

Those things suck, no offense. We build high performance transmission for those things, not a ton, but probably 5+ a year. We see some very high horepower SVT's, the juice isn't worth the squeeze in my opinion.

They are definitely not a high powered race car. In the class I run... mine is about as much HP as they get. The car really shines in balancing through turns and really quick around tight corners.

A Focus SVT took 5th at the National Championships in 2010 and was only 1 second behind the leader. For my intentions (daily driver/stock autocross)... this car is the shiz.

[Extra Point]

Manual trans?

[pr_capone]

Manual trans?

6 speed manual. In fact... it is the exact same tranny that goes into the Mini Cooper S

[CrazyHorse]

Wieght reduction is the way to go here. Because centrifical 3.2 lbs X4 will be huge. The suspension upgrade will help, but not like that kind of weight reduction. I put an aluminum flywheel in an SVT Cobra. Also drilled the pressure plate for weight. The car was much faster.

Nothing you do to the suspension will have the same effect. You will see the effects cornering. You will have little to no advantage in the straights. They already let you use sticky tires. While the performance gains in weight reduction are realized driving out of a turn and in the straights.


Suspension-better into the turn.

Reduction-better straight line speed
-better out of a turn

[MIAdragon]

Have you had professional driving lessons yet?

[El Jefe]

They are definitely not a high powered race car. In the class I run... mine is about as much HP as they get. The car really shines in balancing through turns and really quick around tight corners.

A Focus SVT took 5th at the National Championships in 2010 and was only 1 second behind the leader. For my intentions (daily driver/stock autocross)... this car is the shiz.

Ohhh stock auto will be a blast, my bad!

[pr_capone]

Have you had professional driving lessons yet?

Actually I have. For my bday, wifey got me a 2 day class with the Evolution Performance Driving school. Fucking awesome.

Ohhh stock auto will be a blast, my bad!

:thumb:

[The Dawg]

Lol.

That was my first reaction too.