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Discussion Starter · #1 ·
I understand this isnt a REAL FI question, but it sorta is and i need urgent help.

About a week ago I purchased a set of Konig Reasons from tires.com super cheap 16 inch wrapped in BFgoodrich kd's. They said they would be here in 1 week. They arent. I just walked out side and some a$$hole or someone messed with my tires cuz there is no way that my 2 fronts just decided to go flat all at the same time. I tried filling them and they dont hold air long. Of course I only have 1 donut so thats not an option.

I called tires.com it turns out my rims are in the middle of the ocean right now on their way over. Storm difficulties set the order back (Sounds like what happened with my C2 order.) Everytime i purchase something overseas it gets stuckin the middle of the ocean. Anyways, they are letting me change out my order if i want, very generous of them.

Here is why i put the question under FI, They dont have any 16's in any of the setups that I like, only 17 and 18. Of course im not going to go 18 with my new C2 setup, It would be a waste of good power. But how much will it effect the performance if i put on 17's. Is there that much difference with a turbo'd celi between 16s and 17s. I know when i switched from stock 15s to 16 GTS rims i stopped chirping in 2nd gear. What would you do?

They can ship them to my house by the weekend if I switch my order to the Konig trouble 17's.

Thanks in advance
 

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Whats the weight on them? And what do they look like? If you put 215/40/17 tires on them then they would be the same diameter as the stock GTS rims. Only thing that would matter from there is the weight.

You stoped chirping your 2nd gear because you have better tires with more grip.
 

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Discussion Starter · #4 ·
Only reason i'm scared is because i went to the track with Jay who has the DA sports kit and he ran low 15's all night with konig prohets 18 inch. Then we went 2 weeks later and he had switched to his stocks on teh front and hit 14.4-5. He also changed his exhaust out. So im not sure how i feel about this. It would be a shame to be running turbo and not be consisten low to mid 14s at least. Afterall, i did spend over 3k on this.
 

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Discussion Starter · #6 ·
Hey watch it.. first... its the DA kit.. what more do you want.. his fuel tuning is with a little black box. And.. where are all the GT-T's with 13's. I have yet to see one yet. I only see GTS's in the 13's and they are only running 186 whp.
 

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Originally posted by carboncelicagt
Hey watch it.. first... its the DA kit.. what more do you want.. his fuel tuning is with a little black box. And.. where are all the GT-T's with 13's. I have yet to see one yet. I only see GTS's in the 13's and they are only running 186 whp.
I personaly watched Lark03 run a 13.7 in his Stafford GT.
 

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Discussion Starter · #9 ·
I wouldnt know that since no one has posted a time slip or put their time on the board with under 14 on a GT, except the 3sgte, which isnt really a GT, and the vvtli GT which again is not a GT.
 

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Originally posted by twistedGTS
correct me if i'm wrong, but aren't hevier wheels a bit better for F/I since they will help you keep traction?
i wouldn't think so....you would just want wider wheels and stickier rubber to get more traction...I can't imagine a heavier wheel ever being better!
 

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Discussion Starter · #11 ·
Crap.. hes making me buy their wheel kit, the 5 lugs per wheel at 45.00. Do i need these if i have the ones that came with the GTS rims. Are they universal?? Am i getting a bad deal here, i feel like im getting butt****ed.
 

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I think you guys want to read up about unsprung weight as well hope you guys can take some physics $hit mentioned...
The wheels are not the only unsprung weight on a car, you must consider the brake calipers (which account for a large percentage of the unsprung weight but are not centripital) as well as the suspension linkages such as upper/lower arms, drive shafts, and steering linkages. Now to answer the question as to why unsprung weight is bad, imagine hitting a sharp small speed bump in the road. All of the unsprung weight mentioned above is now elevated and absorbed by the car's bound in the suspention. And here is where it comes into play, is when the suspension must REbound. It's now forcing the unsprung weight back to ground level from it's elevated height. If the unsprung weight is high, then it has gained a lot of mementum from being shot up by the speed bump (or whatever bump it encurred), which forces the suspension to repond slower when trying to slow that momentum and bring it back to neutral position. Now imagin the same situation in say an offroad truck that hits a lot of bumps in succession. It must bound and rebound at a high rate, and if the unsprung weight is great, then it won't be able to rebound completely before it must bound again on the next bump. In other words, if the unsprung weight is very low, then it will be ready to react to the next bump sooner.

Another way to examplify why unsprung weight is so ****ty is by thinking of hitting a bump at an extremely high speed. What would happen to your wheels? It would probably catch some air for a while and you would not maintain contact with the ground, again this is due to the momentum of the wheel, and since momentum is velocity X mass, this momentum would be able to change direction quicker if the mass of the unsprung weight was less allowing your suspension to bring it back to the ground quicker, or hopefully maintain contact with the ground entirely. Even if it wasn't a sharp bump and maybe just a little dip at the track, it really comes into play if you are cornering. Low unsprung weight, again, can be manipulated by the suspention better so your car's tires are maintaining consistant weight on the ground around a not-so-smooth turn and therefore increase traction on that turn.

Now for those of you with bound and rebound adjustments on your dampeners, and you know that you have a high unsprung weight, you can somewhat fight this by setting your rebound dampening lighter then your bound dampening allowing your suspension to decompress faster than it would compress and alltogether having it react faster to bumps and dips, the only pitfall of this is that your you will allow your car to transfer weight faster in the event acceleration, braking, and most importantly, turning. Although weight transfer isn't always bad, it does decrease intial turn in reponse. It would basically work opposite of your anti roll bar. So if you're rallying where there's sharp bumps and you need your suspension to react fast, then set your rebound light, but if you're doing onroad track where you need sharp steering response, don't.
 

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17's are not going to be as bad as 18's, i believe the rotational intertia of a ring (which a rim isnt exactly, almost a cross between a disk and a ring) is 1/2 mr^2. A solid disk is just mr^2, So i guess the rotational intertia of a rim would be somewhere inbetween the two, depends on the design, But reguardless...


What to take from the equation? Its going to get harder to turn the wheel as you add length to the radius... more so then adding mass, because radius is squared. People seem to make a bigger deal about getting light weight rims then getting smaller rims, should be the other way around.
 

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Discussion Starter · #14 ·
Originally posted by Hetts
17's are not going to be as bad as 18's, i believe the rotational intertia of a ring (which a rim isnt exactly, almost a cross between a disk and a ring) is 1/2 mr^2. A solid disk is just mr^2, So i guess the rotational intertia of a rim would be somewhere inbetween the two, depends on the design, But reguardless...

But if i get a lower profile tire than it would be almost like having 16's with the 17's.. correct?


What to take from the equation? Its going to get harder to turn the wheel as you add length to the radius... more so then adding mass, because radius is squared. People seem to make a bigger deal about getting light weight rims then getting smaller rims, should be the other way around.
 

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Obviously it's going to be better to have lower profile tires, less weight. The bigger the radius the slower it gets. Mass (weight) comes second to radius.

With the increased torque from a FI application, i dont think that you will see much of a difference from an added inch of rim. Maybe a tenth or two in a 1/4 mile. That's just my estimate, though.
 

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Discussion Starter · #17 ·
Originally posted by monkeywrench
Keep in mind- shorter sidewall tires tend to hook up worse in a straight line.
****, so go with 205/50/16? or 215/40/17.
And would BFGoodritch G/force sport be ok for a turbo'd car on street?
 

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you'll be fine with 17's. I put my stock 15's for the winter (had 17's) and didn't feel any difference. If you were N/A it would be a different story. i'm going with 18's in the spring
 

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Originally posted by carboncelicagt
****, so go with 205/50/16? or 215/40/17.
And would BFGoodritch G/force sport be ok for a turbo'd car on street?
If I were you and you decide to go the 17" route (which is what i'd do) I would get 215-45-17. I like the 45 better than the 40 for a 17...
 
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