IS F (2008-2014) Discussion topics related to the IS F model

JIC Magic FLT-TAR coilovers on IS-F

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Old 12-26-08, 05:42 PM
  #76  
timeToy
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Originally Posted by lobuxracer
(...)If you understand roll center, roll axis, and roll couple then we can continue the discussion. If you don't, then it's a waste of time.
Total waste of time then...
Old 12-26-08, 07:09 PM
  #77  
lobuxracer
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Originally Posted by timeToy
Yeah, your sarcastic remark about race cars has nothing to do with lowered street cars. Waste of time for someone who has set up cars for dirt and pavement with success.
Old 12-26-08, 07:34 PM
  #78  
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Originally Posted by CrazyMPG
so if we raised the car up from the lowered height to the stock height and played with the stiffness settings would this help on a timed course?
Very possibly. It would depend on the course. If it's glassy smooth, no, but if it's not, you could get better wheel compliance with softer damping and lighter springs.

Originally Posted by oztiks
Wouldn't it have to do with the additional size/weight of the engine, too, or no?
Only a little bit. Doubling the spring rate is extreme. Springs are your first line of defense against body roll and the center of gravity changes related to body roll. Typically when you lower the car and increase the distance between the roll center and the center of gravity, you need a LOT more spring to reduce roll from the coupling effect of those two pieces. Roll couple acts like a lever. The greater the distance between the center of gravity and the roll center, the more leverage the chassis applies to the springs. So, to end up in the same place you started for roll control, you need much stiffer springs. Stiffer != better, and often stiffer actually results in worse wheel compliance, so when you are going over bumpy terrain (like the braking zone going into a turn at a racetrack) and you really want the wheel to follow the contours of the road, it won't. In the extreme, the tire will only contact the tops of the bumps which means you really can't brake effectively, nor can you turn with any precision. ABS only makes it worse because the ABS sees the wheel speed rapidly going from actual speed to locked when the tire loses contact, so the ABS will extend your stopping distance because it is constantly fighting you for control (AMHIK).

On racecars, fixing this is relatively simple by changing suspension parts or moving the suspension pick up points on the chassis. On a street car, it is practically impossible to move the pick up points, so you have to do more exotic things to try and maintain a reasonably short roll couple. One of the most innovative things I've seen on a 2IS is putting a spacer block underneath the front upright above the lower ball joint. This lowers the car without creating problems for the lower control arm - unfortunately to get it 100% right, you'd need to shorten the top of the upright by an equal amount - it could be done, but would require a custom forged upright. If the 2IS were serving track duty somewhere, it is possible these parts would be made and available to the public, but since the 2IS isn't actively involved in a road racing series, I doubt those pieces will be produced.

It's a little disappointing the F didn't take the custom upright approach, it would have been a really simple fix for the rest of the 2IS world to lower their cars without having to resort to super stiff spring rates. See below for the part you'd need to mod and where to make this happen:
Attached Thumbnails JIC Magic FLT-TAR coilovers on IS-F-suspension-mod.jpg  

Last edited by lobuxracer; 12-26-08 at 07:42 PM.
Old 12-28-08, 05:30 PM
  #79  
oztiks
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Originally Posted by mondo540
oztiks, been following your situation and glad you got it all worked out...what settings did you finally settle on? And how would you describe the ride compared to stock on regular roads and/or freeways w/ expansion joints, etc? More compliance in everyday driving? Thx much...
I have the coilovers set to '7' clicks right now on all four corners. I'll probably fiddle with this a little more in the future.

The ride is completely different than stock, in my opinion. The car is much more compliant for every day driving, and doesnt get that nasty "hop" on freeway expansions, etc. The stock suspension was so firm I could get the rear end of the car off the ground on i95 doing 50+MPH on a particularly bad part of the road. With the new suspension and the same part of the road, the suspension definitely takes a hit - but the car stays planted and firm, and it doesn't crush my spine.

Originally Posted by BigMikeISF
Wow, looks great oztiks! I really like the way that makes the car look

Daym, your tint is dark too, limo?
Thanks! The tint is 10% all the way around and 50% windshield. Per the cop's light/tintmeter it's actually 9%, though.

Thanks for the link! Interesting reading.
Old 12-28-08, 05:38 PM
  #80  
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Some more pictures:
(Before):


After:









And pictures of my 'oopsy' yesterday



Old 12-28-08, 06:49 PM
  #81  
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^What happened dude? Dropped too low?
Old 12-28-08, 07:21 PM
  #82  
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Originally Posted by ExclusivIS
^What happened dude? Dropped too low?
Nope.. would have even happened at stock height, but might have been slightly less bad. I was in a hurry going to verizon to get my phone back (long story, they had it all day) and thought they were closing. They have the worst parking situation ever, and there's about a 6-8" high concrete sidewalk right in front of the parking spaces - with no curb stops. I effectively used the sidewalk as a curbstop....... and then found out they were open for another 2 hrs
Old 12-28-08, 07:46 PM
  #83  
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Originally Posted by oztiks
Nope.. would have even happened at stock height, but might have been slightly less bad. I was in a hurry going to verizon to get my phone back (long story, they had it all day) and thought they were closing. They have the worst parking situation ever, and there's about a 6-8" high concrete sidewalk right in front of the parking spaces - with no curb stops. I effectively used the sidewalk as a curbstop....... and then found out they were open for another 2 hrs
DAMN! And I though I had it bad from a little scratch the garage door handle put in my front bumper cover...my condolences...
Old 12-28-08, 08:05 PM
  #84  
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Wow, I thought a little scrape on the front lip was bad, not anymore! That sucks!
Old 12-28-08, 09:26 PM
  #85  
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that sucks! i lowered mine and came about .2 inches from doing that on a curb when i slammed on the brakes and did not hit it! sorry you did bro! good excuse to get a diff bumper! any out yet?
Old 12-29-08, 12:06 AM
  #86  
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It's all good, your F still looks fly!
Old 12-29-08, 12:16 AM
  #87  
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Originally Posted by DFLORES
that sucks! i lowered mine and came about .2 inches from doing that on a curb when i slammed on the brakes and did not hit it! sorry you did bro! good excuse to get a diff bumper! any out yet?
Just the lexon front lip spoiler (well, that's the only one I like). I think that may actually fit and band-aid my damage.. but it will also have even higher risk given the fact it's even LOWER.

Did you do springs or CO's?
Old 12-29-08, 12:18 AM
  #88  
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Another pic -

About .5-1" of clearance coming out of my driveway straight on..


Last edited by oztiks; 12-29-08 at 12:37 AM.
Old 12-29-08, 12:37 AM
  #89  
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haha that's crazy man...but nice!!!
Old 12-29-08, 05:36 AM
  #90  
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Originally Posted by DFLORES
that sucks! i lowered mine and came about .2 inches from doing that on a curb when i slammed on the brakes and did not hit it! sorry you did bro! good excuse to get a diff bumper! any out yet?
Lexon is the only one with a lip out right now for the F (correct me if I'm wrong). I believe AutoCouture is releasing a lip for the F soon. The Fox Marketing IS-F body kit featured on their orange IS-F at SEMA is supposed to be released by bodykits.com "sometime soon." I'm not sure what exactly the body kit comes with though (would assume side skirts and front and rear bumpers but I'm not positive


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