tacostand

alright ive searched around and from what ive gathered is that when it comes to wheel weight rotational mass come into play i get that and its common sense anything heavier will take more power to move but my question is how much weight is too much for an stock single cam specifically 17 x 8.5 that weight 21 lbs. i have stock tear drops in the rear and it breaks grip easily but out of curiosity how much would be to much for a single cam?

mmmS13

17x9 with a 235/40/17 is fine for a single cam. My friend drove with that setup for months.

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S13 stock block Ka-T 16psi Enthalpy tuned
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Croustibat

The OP asked for weight, not sizes.

I am running 17x8 / 17x9 with 235/40/17 all round right now, for 300+ HP.

And my wheels weight around 16lbs each. That is the same weight as the oem wheels.

Anyway to the OP : i was running rims that weighted twice as much, and tyres that weighted twice as much too. Honestly, it does not really matter. There is a bit more inertia but not much. If you stay NA though, there is no point in using more than 205 width tyres (even then, try federal RSR tyres, they wont be the same as crappy 205 tyres)

mmmS13

I guess I should've included wheel weight, but I was assuming common knowledge would dictate an average 17x9 wheel be heavier than a 17x8.5 wheel. Also there is a point to use a bigger tire than a 205 if he does auto-x or something of that nature. Anywho OP if its just a DD pretty much any set of wheels would be fine. Also, any tire 235 or under would be good. 255 and higher is a little too much tire for a stock single cam.

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S13 stock block Ka-T 16psi Enthalpy tuned
*SOLD*

Croustibat

There are 2 things you should not do about knowledge, in general. The first one is assuming. The second one is believing in common knowledge.

Common knowledge is a bitch that will never be on your side.

As far as wheel weight go, it depends on wheel design, material and construction, not size. As i already said, my 17x9 are the same weight as the OEM 15x6, and you can still go lighter.

zerodameaon

Eric Castro has wheels that are like 1 metric ton each(exaggeration but they are not light) and he does not have issues with them on his single cam.

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Need to adjust your idle?
http://zilvia.net/f/s-chassis/395413...-pictures.html

godsmack

Why the concern about weight? Most rims are not going to give you any more advantage of anything as far as weight goes. The amount of horsepower isn't going to be noticeable from a 5lb difference.

Now something that will give you noticeable difference will be the height of your tires. The taller you go the harder it is to spin tires. The shorter the easier. It's not like most things where bigger = more torque capabilities. In this aspect it requires more torque.

DJ-of-E

If you're on stock suspension or less than 2 way suspension, you are right about this one.

If you're on aftermarket and going for auto-x for pole position, it can make a difference on stock KA engine because you're trying to squeeze as much as possible. More than 250HP turbo? I wouldn't care even if they weight 25lbs on each wheel

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Kingtal0n

some people go through length to remove 2 ounces of electrical tape and wiring from their harness.

Saving weight from rotating parts, like wheels driveshafts rotors flywheels crankshafts rods piston ring drag accessories/pulleys is a great way to free up horsepower and increase fuel economy. It counts for more when you take it from rotating parts, then when you simply remove it from the dead weight. I would rather reduce my flywheel weight by 10lbs than remove 20lbs of spare tire/sound deaden.

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BossHogg

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Croustibat

Blah blah blah, i already told you an infinite number of times that you suck at real life thinking. Theory ? I live in real world. Theory gives an estimate to point people in the right direction.

But Practice tells people theories are often wrong because of a simple, overlooked detail. The overlooked detail here is the tyre, which has a limited traction. The very same reason a heavy flywheel makes an engine easy to control, heavy wheels and tyres make a chassis easier to accelerate and brake to the limits.

What i know so far is that removing 16lbs on each corner or my car did not increase fuel economy by a noticeable amount. Really. No change at all. My flywheel went from 24lbs to 10. Nothing either.

It did not improve my acceleration times, nor did it decrease my braking distance.

Quite the opposite actually. Because of the removed inertia, locking the wheels / spinning the wheels happens more. Wheel inertia is the friend of every lead foot driver. And we dont drive formula 1 cars here, these are 20 year old worn S chassis. Not precision tools. They are meant to be driven by burying these pedals. No delicate driving.

Now if you really are a good driver, have a very good pedal feeling and control, and an absolute need to improve your times, then by all mean reduce wheel inertia.

But If you are not ? Forget it. Driving will just be harder.

Kingtal0n

So, just to be clear, your reason is that everyone sucks at driving and thats the reason why not to reduce rotating mass. lol


Crusti, aluminum connecting rods exist, and so do lightweight flywheels and lightweight driveshafts. If those parts didnt work, they wouldnt keep making them for years and years. People would eventually figure it out and stop buying that product.

YOU didnt notice the increase in fuel economy and acceleration because YOU did not have the right logging tools or engine setup. I, with my little data-logger software and my lead foot on the dyno DID notice a difference in fuel economy and acceleration when adding a knife edged crankshaft to an SR20DET for instance.

Just depends on the setup and intended use for the vehicle. Lighter is better in general because rotating mass is an energy hog. Thats all Im saying and its dead accurate.

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Croustibat

Seriously...

This is the last time i waste my life answering you.

so...
1/ business 101: sell what people want, not what people need. People keep buying chassis braces made of chinese cheesy metal. Or pills that make you lose weight. These things NEVER WORKED in the first place. And they keep selling. Your argument is invalid.

2/ i never said getting lighter parts had no impacts, i said most people dont need them and cant tell the difference nor get some benefits out of it. Yes, that includes at least 90% of zilvias members. Including me. You ... well you are just a lying fool so i dont know if i should count you as a driver.

3/ fuel consumption. You have great logging tools. I have a simple calculator that can do "fuel added at the pump / mileage done since last refill" . Guess what ? THAT is what fuel consumption is about. 5000 miles later, my fuel consumption is still the same as before. So i really dont care what your fucking damaged brain tells your fingers to type. MY FUEL CONSUMPTION HAS NOT CHANGED, AND I DONT NEED A FUCKING DATALOGGER TO COMPUTE THIS.

4/ Rotating masses act like a capacitor. They dont hog energy, they store some, then give it back later. What matters is how much energy. The answer is nearly none.
You like calculators ? Try this one.
Flywheel Energy Storage Calculator - Kinetic Energy, Inertia, Centrifugal Force, Surface Speed

At 100km/h, an S13 standard diameter wheel + tyre has a diameter of 618mm and turns at 860rpm.

In the worst possible scenario, if it weights 32lbs, and all the weight would be on the outer diameter, the whole wheel at 100km/h has 12 joules stored in. If the weight is even (disc form), that goes down to 6 joules.

Cant you see how this is ridiculous low ? Yes, going for half weight reduces it to half of this value. But guess what ? THAT IS STILL NEGLIGIBLE.

FFS providing 6 joules with a 300HP engine takes 27 DAMN MICROSECONDS.

5/ go fuck yourself and get some brain surgery, twat

Kingtal0n

"Regardless of the equivalent weight ratio, you're best off reducing weight as much as possible, as you might expect."

some of us expect

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VNG704

Croustibat, whoa there. Sounds personal.

OP, maybe you're asking the wrong question. If your concern is traction, look into tires with more traction.

Croustibat

To be honest, i have never met anyone that gets on my nerves as much as him.

He is completely crazy -i mean it, check his posts if you are not yet convinced, he never make any sense, and he is a crook -again this is for real, he recently sold a car to a zilvian telling him it was normal to overheat when going more than 65mph with it, because SR20DETs are old sensitive engines, and that he should "disconnect the turbine" to get rid of the problem.

I have no idea why he is not in a mental asylum. And i'd really like to know why he is even allowed to post.

I made the mistake of removing him from my ignore list, because i thought he could have gone better.

Seems not. So he is back there for good.

Kingtal0n

I Sold the car to a young 20 year old who should not be driving above the posted speed limit of 65MPH and told him to just drive 65MPH. He wanted to cruise at 85MPH and 3900+RPM in boost half the time so yeah the OEM radiator was not up to the challenge. He changed the radiator, as you well know, and that was that. I was against changing OEM parts; better to just drive the speed limit. This is after you claimed it had a warped head!! nice call Crusti.

You keep telling this story like its some kind of crooked deal. I sold a perfectly OEM vehicle with not a bolt or nut missing and you act like it was a faulty project car.
Keep slandering my name harassing me it shows what a big man you are.

__________________
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https://tinyurl.com/turbo240

tobroketobuildarealcar

Wheel weight differences are greatly noticeable when I go from some cheap drift beaters to my rpf1's I feel a difference in the cars steering and acceleration

Kingtal0n

Crusti says weight saving is negligible so everybody put their interiors back into their race cars.


UMAD?



Also I would like to know how to "provide" an engine with 6 joules to take 27 microseconds. Or what you even mean by that.

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5.3/4l80e/turbo 240sx playthrough:
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Croustibat

Arent you claiming to be good at maths and theories ?

Try "joule" definition, and if you still have some working cells in your brain, you should figure it out by yourself

(damn that "view post link")

Croustibat

That is because they have different total diameter, different offsets maybe, and maybe also because the first ones are bent.

tobroketobuildarealcar

I run the same brand tires with the same overall diameter meaning the tire rotates the same ammount of times per mile and no the wheels are not bent weight makes a huge difference bottom line if you don't beleive it go talk to any serious race team and see ic you can convince them to run heavier wheels

godsmack

So I'm guessing here that the difference is in the rim size? Like 16 to 17? If so you will notice a difference since the sidewalls will be smaller causing the tire to grip the road more rather than flex while cornering.

And a serious race team needs that extra .05 of a second that running 5lb lighter rim will net you. Now if you're taking 25lbs off then yes you will notice a difference. The op is asking about 21lb rims that he won't really notice a difference with.

Like I said previously the easiest way to notice a difference while working around rims is tire size. Use a 215/40 compared to a 215/60. The difference is extremely noticeable.

DJ-of-E

YES, if you're driving nankang tires with super soft sidewalls.

And no, not really on even quality street/track tires like BFGoodrich Rivals or Dunlop Z2s.

A lot of misinformation going around here and I felt the only one who was right was Croustibat.

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Croustibat

Dude, i dont care about "serious race team" and whatsnots. I am not into serious race driving, i am not a pro driver either, and if you are driving an S chassis, you are not either.

Fact n°1:
I already computed the inertia impact on accel /decel time in a previous post, and it is ridiculous with the engines we use. No human being would sense a 30µs change. The only way to feel it is to drive a low torque / low power car, with a huuuuge change in weight. This may have applied 40 years ago. Not now.

Now this is not the only effect in action and the gyroscopic effect could have an impact on the front wheels, but then again i have power steering on my car so i totally dont care.

Fact n°2:
I went from 215 width tyres, 40lbs wheel+ tyre combo to 235 width, 24lbs wheel + tyre combo.

No real differences, except i now lock and spin the wheels easier. tyres are better too, and i dont have a stupid alignment that makes only half of the tyre touch the road. Fact is, i could bury the gas pedal without worrying too much before. Now, even with a torsen, i cant. It may be a bit better, but it is also a lot more difficult. Maybe a pro driver can cope with that easily, but what i say is most people dont or dont want to. I have no race to win, i drive to have fun, and while i like shaving seconds off my times, i have no need for that. If going always faster means ruining my fun, then i dont try to go faster. Which is exactly why i dont want to be a pro driver.

So yes, based on MY experience, there is no SENSIBLE gain for most people (maybe if i put it in caps and bold you will be able to see it this time ? ). People who really can gain about that usually dont post on forums.

tobroketobuildarealcar

You are entytled to your opinion like I am entytled to mine

You keep mentioning that lighter wheels spin to easily and lock up to easily I underrstand your theory (does not make mine or yours right) but where I am from having a car that you can't pedal properly without spinning or locking up is called poor driving not hey it happend because my wheels are to light

Back to the origonal question what is to heavy for a sohc ka
In MY opinoin you need all the help you can get because they don't make much power. I recommend getting the lightest wheels your budget can afford and/or save up and make more power then wory about wheels

Kingtal0n

Thread:
http://zilvia.net/f/engine-tech/5171...s-highway.html
Crusti:
Me:
Me again:
Solution:
Apparently I was still wrong after suggesting a new radiator as one of the options (twice). Shows you how well people can read.

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https://tinyurl.com/turbo240

Seraphim38

I created a spreadsheet that logs weight by manufacturer of all relevant size wheels.

I really want to go wider and care about wheel weight, since I can't get 275/40/17s on a 9.5 inch wheel to stick.

Sure, Mustang guys roll around on 17x10.5 wheels that weight 31 pounds a piece, when your average 17x10 on a 240 weighs around 20 pounds less, each.

Are you personally going to notice a difference when you swap out wheels, assuming that you use exactly the same tire? No idea.

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The Dude

Wheel weights are important if:

1. You are into competitive racing.
2. You like the smell of your own farts.

tobroketobuildarealcar

Opinions are like ass holes every one has one and they all stink

Now on to the facts no matter how noticeable it is with less weight acceleration , turning , and stopping require less effort we all learned this in middle school guys and gals

It is up to the indavidual to decide if that is advantagous or a hinderance