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Thanks for your hard work bro!
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You guys worry too much about a few pounds here and there.
From my roommate who is a professional drag car builder (for Inline Pro) "If its a street car, don't worry about weight, worry about making power". |
Weight is power. Ask a drag racer which they'd rather have. Minus 50 lbs, or 5 hp.
Its all about power to weight. Increase your weight, and you have to increase your power to compensate. Increase your rotational mass, and the power increase required to maintain similar power levels increases by a factor of 2.2-3x. Its all in the orgy of urls...but nobody can force you to look at them. http://www.nerocam.com/SCC_TAPnew.asp 2.0 seconds off the 1/4, and they didn't increase power at all. :D |
Originally Posted by cretinx
You guys worry too much about a few pounds here and there.
From my roommate who is a professional drag car builder (for Inline Pro) "If its a street car, don't worry about weight, worry about making power". Excellent summary, crossbow! Regards, Gordon |
A bullseye for crossbow :cool: great info ;)
cheers michael |
Excellent compilation. Drag racing carries different priorities than turning the wheel. If I had a choice of losing an extra 100lbs or making an extra 10hp, I would take the 100lbs.
HP helps with acceleration. Weight helps with acceleration, turning, stopping, and wear. |
Can we get this to be a sticky?
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I guess you guys didn't understand my post
I know weight is power, he does too, on his drag cars they save every pound they can. HOWEVER - there's a point of diminishing returns, and on a street car, its really not worth it to sweat a few pounds here and there for rims or amenities - if you have two identical looking rims, one that weighs 20 lbs and costs $205, or a rim that weighs 16.5 lbs and costs $495, there's little justification for spending the extra money unless you're professionally racing. I see little to no point to stripping down a daily driver or a street car and worrying about weight when making power is so much easier and cheaper. |
Nothing really justifies buying an RX-8 over a Hyundai Elantra either.
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I think the fundamental problem with the whole rim/size/weight thing...is people hate to think that their multi-thousand dollar investments in their cars appearance subtracted power. They like to be under the firm belief that there isn't anyway you'd notice a few extra pound difference on each wheel, and that it doesn't matter whatsoever.
But it does. It matters so much that most people can notice as little as a 3 lb difference in unsprung weight in just a few minutes of driving ((3 lbs less per corner). More substaintal differences can change the entire feel of the vehicle, to the extent that you think you've bought a new car. Of course this is possible to explain or get across to individuals, cause in their head (12 lbs is absolutely nothing). Its only when those individuals finally try something drastic, that their tunes change, and suddenly you'll see them posting on how to fit the smallest lightest rim possible, and still have rotor/caliper clearance. I'm almost positive that if you added up all the current available NA mods on the 8 (pullies's, intakes, catback's, midpipes), it still wouldn't match the difference going to 17x8 SSR comps, with lightweight rubber on them. (36.6 lbs with 245/40/17 T1-S) [Especially if you look at the overall effect on acceleration, handling, braking, and gas mileage increases] I don't think its that we didn't understand your post, I think its just that you have don't understand the effect of unsprung weight on a car...which is the whole point of the orgy of urls...with over a THOUSAND testimonies on the effect...with drag slips, autox times, road course times, g recordings, articles, and statements to the fact. |
Originally Posted by cretinx
HOWEVER - there's a point of diminishing returns, and on a street car, its really not worth it to sweat a few pounds here and there for rims or amenities - if you have two identical looking rims, one that weighs 20 lbs and costs $205, or a rim that weighs 16.5 lbs and costs $495, there's little justification for spending the extra money unless you're professionally racing.
I see little to no point to stripping down a daily driver or a street car and worrying about weight when making power is so much easier and cheaper. A point of diminishing returns? Yes, but going from 20 lbs to 16 isn't there yet - it will be a very noticeable return. You really ought to experience it yourself before you dismiss it! Regards, Gordon |
As stated by others, your buddy has lived with drag cars too long if he thinks a lightweight sports car wont benefit from losing 4 pounds unsprung weight per corner.
I dont race professionaly and I dream of getting some SSR's on my car, just to lose those 8 pounds per corner. |
Look at it this weigh
Assume you have the GReddy turbo kit installed, ok. You can spend $200 / wheel on some 23 lb Kazera KZ-As, for $800 OR you can spend $500 / wheel on some 16.5 lb SSR Comps, for $2000 Now, you guys can all get your SSRs, I'll spend the remaining $1200 on a custom 3" exhaust (making it safer to increase boost) and a boost controller, safely raising boost to 9 psi (where the stock fuel system should start getting challenged) and enjoy blowing you away, on the circuit, strip, or street. The place where you'd see the big big benefit of saving a few pounds per corner of unsprung weight would be the autocross. Weight consciousness is a disease I see drivers of underpowered cars get sucked into repeatedly- it just starts to consume you - seen it with the Civic drivers, Celica drivers, and I'm seeing it with the hardcore RX-8 racers. If weight were the real concern, you'd be on 16x8 rims all around, and you would ONLY buy the base model, without DSC or leather or nav or any of the things that made me buy an RX-8 instead of build a 3000GT VR-4 to 500 awhp for the same price, or get a 420 rwhp turbo S2000, again for the same price. Like I said, its your money, if you want to lose those 8 lbs per corner and beat a stock RX-8 by a a good second or two on the autocross, that's your deal - autocross is a lot of fun! Me, I'll settle for some "heavy" 23 lb rims and put the money into neck snapping acceleration, and a midrange response that doesn't remind me of stepping on a rotten tomatoe. |
Lotus Elise anyone? :)
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So whats the lightest tires one can get for the 8 ?
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One analysis that I think should be placed above is the following:
https://www.rx8club.com/showpost.php...9&postcount=22 Through those equations I determined that the 1.5 lbs of non rotating weight is equal to 1 lb of wheel weight - worst-case. (Another forum member did it a different way and got the same answer.) Meaning that in terms of acceleration, having a 36 lb dumbbell in your rear seat would slow you down more than having wheels that weighed 6 lbs more each ( 36lb = 6lb X 4 X 1.5 ). At best the lighter wheels (or removal of dumbell) would translate into a 1/15th of a second improvement in 0-60 time. I definitely don't think that straight-line performance difference is worth the $1200 difference in wheels. (It so happens I own KZ-A's and was seriously considering SSR Comps) As far as handling, how much unsprung weight matters is going to be very subjective and no one has done blind or double-blind tests to prove otherwise to my knowledge. Instead of someone buying new lightweight wheels and knowing that they should feel a difference, it would be more interesting to put someone in a vehicle not knowing what wheels were on the vehicle and see how much their track time improved. I wish a had more time to get into it but I don't think Miata is the ultimate comparison vehicle for determining the effects of unsprung weight. You are talking about a very light weight vehicle without a whole lot of power being driven on very tight test tracks. Those conditions amplify the role of weight. Miatas also don't need tires and wheels that have high load ratings either, so using light-duty equipment doesn't have as much downside as it would on a heavier higher power vehicle. One last thing to keep in mind is that Tire Rack uses a BMW 330ci to do their tire comparisons (I wish they would do wheel comparisons as well) and there is very little correlation between tire weight and subjective and objective tire performance measurements. The S-03 by Bridgestone is a heavier than average tire and it does very well in the performance tests. Many of the lighter tires don't do well. All cases for or against an idea should have both sides represented. Before people spend $2000+, they should have a better understanding of what to expect in terms of straight line performance and overall handling. There are two sides of the coin here. The first post shows all of the positives mainly in the form of subjective opinions which are possibly quite prone to the placebo effect. -Mr. Wigggles |
All I can say Cretenix about your argument that saving weight is a lost cause... is that a journey of 500 miles (or 500 lbs) begins with the first foot (or the first lb.) You say that people are all crazy spending their money to lose weight from their cars.
If you just throw up your hands and say "not worth it", well that's anyones choice. But it's obvious, I think, that weight costs too, big time. The costs to 'makeup for weight' are exemplified in the need to add lots of HP to go faster, quicker, and bigger, beefier everything else to handle that weight and added power, extra wear and tear on it all, plus real world handling & performance suffers carrying extra weight both down the straight and around those corners - every single lap - no matter what. It is simple physics. Weight consumes power, and impedes handling. There is reason to try to lose 10, 20, 50, 100, 200 lbs, whatever the figure. Of course the BEST answer :D is to loose the weight, gain the HP, then go like a crazy person to the finish line. It's not just about the money. But just saying loosing weight is a non-starter "so don't bother, just get a turbo" is wrong-headed IMHO. :) |
wouldn't gas milage increase slightly with a lighter car? Over 100,000 miles you might see some of that 2000 bucks back into your pocket in savings on gas right?
someone should do that math on that! :) |
Originally Posted by Jarred
wouldn't gas milage increase slightly with a lighter car? Over 100,000 miles you might see some of that 2000 bucks back into your pocket in savings on gas right?
someone should do that math on that! :) |
Originally Posted by cretinx
If you guys are worried about gas mileage, you certainly got the wrong car, and you shouldn't modifying any car. You should be driving a stock D15 Civic or a Miata.
Also, for auto-x I went the light wheels route and smaller diameter. My wheel/tire combo is 7.6 pounds per corner lighter and I lost an inch in diameter. I agree that going a few pounds lighter for track day activities or general street driving is kind of a waste of money just like the lightwieght flywheel or rotors, all of which reduce rotating mass. But if you are actually competing where tenths of a second matter and the rules don't allow power adders like a turbo or nitrous, I say go for it. |
I don't get this it's a waste of money arguement about buying lightweight mods for the 8?
People go and spend $2,000.. $3000.. $4000 or more on a plasma/LCD/DLP television.. is that a waste of money?...they could get by with older, heavier $1000 versions. People go and spend $2,000.. $3000.. $4000 'making pretty' their cars in too many ways to count.... that 'pretty' is argueably in the eyes of the beholder..so is that a waste of money?... they could do noting...that's cheap... or worse do something and make it worse. Money is meant to be spent, it gives you power to do what YOU think is right, what you want to experiment with. Someone may go spend $2000 on lightweight wheels, $500 on a PPF, $1000 on a flywheel set, etc. "Because it is lighter" has value to some that others don't appreciate regardless of whether your turbo gets you their faster. [ I say that because the benefits are there and based on physics, whether one recognizes them or not ] :) If you can accelerate faster than me, I applaud you. In turn if I can go through the twisties quicker than you, I'd expect the same. Last time I checked, moding personal cars wasn't a contest based on value for ???? |
Like I said, "I agree that going a few pounds lighter ...... is kind of a waste of money ....." That's just my opinion. I have no problem with people dumping loads of cash into a car. To each his or her own - it's their money. Improving the looks and performance of one's car is a worthwhile endeavor.
I just hate seeing somebody throw an $800 lightened flywheel in their car and then stick heavy 19" bling wheels on negating the effect of the flywheel. I did the math and for me the added performance and cost savings of the 17" wheel/tire combo made sense. The $280 I save each year on tires will pay for the wheels in three years. And I'm also seeing the performance benefits of the smaller diameter tires and lower unsprung weight. |
Originally Posted by Dark8
I just hate seeing somebody throw an $800 lightened flywheel in their car and then stick heavy 19" bling wheels on negating the effect of the flywheel.
Me, I'm totally up for (light) 17" wheels, damn the cost (savings)!:D |
If you want power and don't care about extra weight the best thing you can do is sell your 8 and buy a 350Z
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Look i've noticed everyone here argue that weight loss is great and its benefits and others say its not worth the cost...both sides are right but these are all opinions. If we all agreed all of our 8's would be identical and that would kinda piss me off...I'm striving to have an 8 that is not similar to anyone else's. Personally I'm a daily driver but i want volk GT-U cuz they are phat and well THEY ARE VOLKS BABY!!! i could care less about the weight all tho i would like to improve my car's power. Anyways what i'm tryin to say is that its whatever makes u happy, and whatever you think looks good then do it! our differing taste is what makes it interesting to compare rx8 pics. Its all about hey what do u have???....oh yah check out what i got....but if its all the same light weight fly wheels light weight rims....then it gets kinda boring. Anyhow keep on tryin to be different people. I'm loving the pictures of everyones 8. ***REMEMBER YOUR 8 REPRESENTS WHO U R*** a car is a personality. So whats your personality?
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alright...so how much do the Stock 19" rims weight??? I am buying the PIAA super Rozza 2piece rim which at 19"-8.5" weighs 26.5 pounds. is the stock rim less or more ???
thanks -Max |
stock 19s???
18s weigh like 23lbs... pretty light compared to a lot of other factory rims. Best motoring did a comparison with the evo mr with its standard evo rims and the lightweight bbs rims, outside of the drivers positive comments on the lightweight rims, the improvement in time was minimal. I guess its depends on how drastic the weight change is. I have lighter flywheel with the ssr comps, car brakes overall better and it feels like it drop a passenger so overall i think it was a good investment in my part :) |
Well, I made the plunge to Kazera S Chrome wheels at 26.5 lbs with Michelin Pilot Sport PS2's from Tire Rack, as my stock tires were worn out. After that, I had the old tires dismounted from the stock 18" rims, and took the 18" rims home, washed off all that old brake dust (the new chrome wheels don't build up NEAR as much after 2.5 weeks) and weighed the original wheels, and guess what? They weigh just about the same at 25-26 lbs! Nice to know for myself. I love that new sticky, stiffer ride!
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I can feel 2 pounds a corner difference and I suggest that most drivers could if they had similar opportunity to blind test as I have. The difference IS felt as much on the street as it is on the race track. On the street the prime benefit is ride quality...the lighter the wheel and tire package, the better the ride quality because the suspension does not work as hard to slow up and down momentum of the wheel and tire package meaning less NVH is transferred to where you are sitting. There are good reasons that unsprung weight reduction is a holly grail of automotive engineers and it is not just details of handling that only an autocrosser would notice.
Happy riding faster and smoother than stock on 17.2 pound 18x9.5s on all corners... Brian Goodwin Good-Win Racing www.good-win-racing.com |
Brian which wheel are you using? I'm interested in a lighter wheel.
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I was going to see the difference in size with the same tyre.
My question is do you have experience on the following? "Somone chose a 245 on a 8" 8.5" and 9" and tested it and the 8.5" and 9" runs a second a lap faster on the same size tyre" As in weight, my Enkei 18x8 is 8.3kg is much lighter than stock 10kg. I put some semislick Potenza RE55S on the stock rim and beat my lap time by 4.5 seconds. I drove better of course, but at least I think I am not going backward. |
Originally Posted by Razz1
Brian which wheel are you using? I'm interested in a lighter wheel.
Enkei RP-F1....18x9.5 and 17.2 pounds. That's lighter and less expensive than the same size SSRs. I have pics up on our site if this link does not work: http://www.good-win-racing.com/mazda....php?p=194#194 On takahashi's question, yes, you get more performance from a given tire size if the sidewalls are better supported which is why I run the 9.5s. Stock class autocrossers are stuck under the rules with 8 inch wide rims but run the same tire size I do, 275s. I run STU class and don't have the limitation of 8 inches so I run the 9.5s to get better support of the sidewalls (particularly helpful given I am in a street tire class). As the ratio of rim width to tire width improves the tire rolls over less and the initial turn-in is sharper and more consistent. Thus, in your example, it is no surprise that the 245 wide tire is going to perform better on the 9 inch wide rim than it does the 8 inch wide rim (to think of it another way, 245/25.4mm per inch means that 245 tire is roughly 9.6 inches wide and that makes for a real angle to the sidewalls on a 8 inch wide rim which you fix significantly by going out to a 9 inch wide rim for the same 245 size.). Brian Goodwin Good-Win Racing www.good-win-racing.com |
Originally Posted by Jarred
Lotus Elise anyone? :)
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I've had arguements with my friends on this stuff. They keep telling me go wider in the rear. I've seen people do this on FFs (got to love SOME Civic owners)!!!! And then claim they handle better!!!! :eek: :eek: :eek:
The 8 is 50/50 ~ balanced. So the wheels should be balanced also. I'm getting 18 x 8s or x 8.5s. Maybe some Enkeis or Grams Lites (probably Enkeis cause they are a lot cheaper than the Grams). As far as tires, I don't know. Maybe some BFG KDWs or Falken Azenis 615s. |
It has been noted here time and time again by many experienced racers, staggard setups on the RX8 do NOT improve handling. If folks want staggard because they think it looks cool that is okay by me but please do not think it improves handling....adding unnecessary weight and upseting already perfect balance is not a good thing for handling. If you want staggard setups buy a Porsche 911 (post rear axle motor gives it a rear bias and high polar moment which benefits from massive rear tires).
I was instructing at the MazdaFest at Buttonwillow Raceway a few months back and we had some very fast full race trim Rx8s fron Mazda on hand....and those full race trim RX8s had the same size wheels and Hoosiers on all four corners. In contrast, the street guys with staggard setups are consistently back of the pack beginners that do not know any better...but they sure look cool going slow. OR to put it another way, as soon as I get passed by an RX8 on a staggard setup I will be happy to let you know. Weekend after weekend it has not happened yet but perhaps when I am too old to reach the gas pedal it will finally happen. Brian Goodwin Good-Win Racing www.good-win-racing.com |
Brian, what is the smallest size tire (i.e. 225/45 or 245/40) that will fit on the Enkei RPF-1 18x9.5? I was thinking a 275/35 would weigh a few more pounds then a 245/40 or even more than that vs. a 225/45. And if the 275/35 is the only size that fits the 9.5" rim, can you get the wheel in an 8.5" or 9" that would accomadate the lighter 225/45 tire? I hope this question makes sense.
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My Miatas use 215s (street) and 225s (autocross/track) at nearly 800 pounds lighter so it is no surprise I like a little bit more stick than stock 225s on the RX8 for the aggressive street setup. I think the 245 is the first step up for street and you can run the 245s on the factory 8 inch but I would get at least a 8.5 which is, frankly, "enough" for street use though you can run that size on 9s and 9.5s. Certainly the 9.5 is going to give you the most performance out of that tire but I should note that the downside of giving the sidewall all the support it can take is that you are more at risk for curb rash with the 245 on there. If looking for a dual purpose setup for street/track/autocross the Falkens in 275s provide amazingly good ride (surprising that the Falken 615s are so smooth given that the old Falken Azenis were such bruisers). I should note that many are also running 265s happily for a dual purpose setup...
Brian Goodwin Good-Win Racing www.good-win-racing.com |
this thread has so many generalities it's not funny.
Light weight alone is not necessarily a true picture. Light weight means nothing if the wheel flexs under load, It often happens that a heavier wheel can have a lower inertia than a lighter wheel; SSR wheels are notoriusly light in the hub area where there is little impact on inertia with excess mass in the shell area which has the largest impact on inertia. How the weight is distrubuted across the width i.e. relative to the lever arm working on the shock/spring, also has an impact. So to simply say this wheel weighs less than that one and is better or 1# rotating mass = 1.5# of non-rotating mass is false science. It just depends ... .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. ........ :cool: |
Lovely how you put that last paragraph in yellow. I agree with you though.
Weight is the single most important factor in purchasing rims for me. I went the route of good looks/not caring about weight the first time. I ended up with a set of rims that were 24.1 lbs each. It completely killed to fun in the car, everything was slower, the ride sucked because the springs/shocks couldn't do their job. I ended up sacking those wheels for some 18.5lb Enkei RPM2. At the time i bought them i didn't like the look at all, just wanted a light strong rim (Boston roads are terrible). Now i almost wish i went lighter than that. Ther difference is unmistakable. |
just wanted to know how much does the stock rx-8 rim weigh
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Originally Posted by axelaspeed
just wanted to know how much does the stock rx-8 rim weigh
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Originally Posted by RPIRX-8
Approximately 22.1lbs. Take a look at Brillo's vbGarage. He used to have pics posted of the stock rim on a scale with a weight displayed.
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you might want to recheck on the shinka rims. I'm not sure if the alloy used is different than the regular RX-8 18 inchers or if the rims are just painted a chrome color.
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Originally Posted by RPIRX-8
you might want to recheck on the shinka rims. I'm not sure if the alloy used is different than the regular RX-8 18 inchers or if the rims are just painted a chrome color.
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Originally Posted by axelaspeed
nice, i'll have to check it out, i just bought a set of rx-8 shinka rims for my 3, i was looking all around to find out how much the weighed but couldnt find anything
We are probably getting a Mazda 3 rather than a 6 (don't need the size of the car, just the same engine).... if it fits the 8's wheel than I will have a new wheel for track day. :) |
Originally Posted by takahashi
Does the stock 8 rim fits into the 3? I know it fits for the 6.
We are probably getting a Mazda 3 rather than a 6 (don't need the size of the car, just the same engine).... if it fits the 8's wheel than I will have a new wheel for track day. :) |
Sweet.......
What is the stock wheel offset? I wonder if it will fit on my 8 for some drifting practice? (you may see the offset in the inside of rim). We are only 1 kid family and not expanding atm so I think we like the 3 more now, plus a few $K cheaper - sparing some cash for mods on my 8. Oh found the answer: http://www.mazda3forums.com/index.php?topic=25387.0 |
Originally Posted by takahashi
Sweet.......
What is the stock wheel offset? I wonder if it will fit on my 8 for some drifting practice? (you may see the offset in the inside of rim). We are only 1 kid family and not expanding atm so I think we like the 3 more now, plus a few $K cheaper - sparing some cash for mods on my 8. Oh found the answer: http://www.mazda3forums.com/index.php?topic=25387.0 |
You can be my Mazda salesman. I am sold on the 3! :D
Oh my love to do the drifting on the 17".... LOL Must go and test drive the 3 in the weekend then. |
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