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Old 08-22-2013, 03:03 PM   #3101
Atomic Rooster
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AHK, what's the mehcanical whining noise in the dry part of your video, but absent from the wet part? My car has makes the same noise on occasion and I've no idea what it is.

Also, you sure shuffle your hands a lot. You seem to really good at it but it might help to nail them down a bit.
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Last edited by Atomic Rooster; 08-22-2013 at 04:01 PM.
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Old 08-22-2013, 03:17 PM   #3102
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Quote:
Originally Posted by AHK View Post
From your suggestions it looks like the next step will be adding a front ~24mm bar w/ end links to help reduce front dive a bit and setting my rear 25mm to soft.

Also please keep in mind, I plan to use my car for HPDE's at VIR, Summit Point, etc. so I also don't want to make my setup too autocross specific. Meaning I don't want things too twitchy for high speed cornering.
you could probably go a bit bigger in the front, adjustable maybe? You'd then probably want to keep the rear on medium (or stiff, imho). Great thing about bars is, you can soften them up for the track Or soften the rear only for an even more "forgiving" setup.. same for rainy events... or bumpy events... or both
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Old 08-22-2013, 04:30 PM   #3103
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Quote:
Originally Posted by AHK View Post
Thanks a lot fellas and that link SolidSTI posted has some great insight.

Right now I have Perrin 25mm on medium w/ Whiteline brace support in the rear and stock front bar. This was obviously not how I wanted to leave things but only a start to my suspension tuning as I was hoping a few pieces at a time might give me a better result instead of doing everything at once and not knowing what the hell is doing what.

From your suggestions it looks like the next step will be adding a front ~24mm bar w/ end links to help reduce front dive a bit and setting my rear 25mm to soft.

Also please keep in mind, I plan to use my car for HPDE's at VIR, Summit Point, etc. so I also don't want to make my setup too autocross specific. Meaning I don't want things too twitchy for high speed cornering.
As long as you stay adjustable you should be fine for adjusting the rear for road courses. The thing I notice the soft rear bar helping the most with is off-throttle rotation. This really helps get the nose around those tight autocross layouts.

I'm going to try a HPDE using my autocross setup sometime to see how wrong it is. I've been on a partial road course at a state level autocross event and honestly my car felt too soft in the rear.
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Old 08-23-2013, 02:54 PM   #3104
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Good points Doug and Solid.

Atomic, that was the engine/tranny noise captured by my front mount GoPro in the dry video. I did not have the waterproof back so I had to take it off for the Day 2 rain. Not sure the exact component that whines but I know all the other 2008+ WRX/STi's do it to some extent. It reminds me of the sound WRC cars make
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Old 08-23-2013, 05:29 PM   #3105
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The whine is pronounced by urethane front and rear shifter bushings, and especially so if you have a trans mount and/or a pitch stop.
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Old 08-27-2013, 10:29 AM   #3106
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Quote:
Originally Posted by AHK View Post
From your suggestions it looks like the next step will be adding a front ~24mm bar w/ end links to help reduce front dive a bit and setting my rear 25mm to soft.
Please note, a front bar will not do anything to reduce dive, as swaybars are effective only in increasing roll stiffness. Or, put another way, they only act upon lateral load transfer, not longitudinal. Only way to reduce dive is stiffer springs.
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Old 08-27-2013, 11:18 AM   #3107
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Quote:
Originally Posted by Illini_STi View Post
Please note, a front bar will not do anything to reduce dive, as swaybars are effective only in increasing roll stiffness. Or, put another way, they only act upon lateral load transfer, not longitudinal. Only way to reduce dive is stiffer springs.
I don't agree. Compressing both arms of the front suspension will cause the sway bar to flex. Stiffer bar will have less dive. I've noticed the front was overall stiffer on bumps when I was on a 22mm and stock stuts/springs.

Let me know if i am crazy
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Old 08-27-2013, 11:25 AM   #3108
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Quote:
Originally Posted by AHK View Post
Good points Doug and Solid.

Atomic, that was the engine/tranny noise captured by my front mount GoPro in the dry video. I did not have the waterproof back so I had to take it off for the Day 2 rain. Not sure the exact component that whines but I know all the other 2008+ WRX/STi's do it to some extent. It reminds me of the sound WRC cars make
Finally watched your video, and that's quite a bit of whine. Pretty sure that's not from stiffer trans/motor mounts...but I have a good idea of what it might be.

When was the last time you changed your power steering fluid? Subaru's are notorious for power steer pump noise, and even brand new GR's have the issue. The root cause is that the power steer pump and lines are very close to the hot turbo and exhaust, which heats the fluid and rapidly fatigues the PS fluid. The solution is more frequent power steer fluid changes and/or adding a power steer fluid cooler.

My 08 STI had a very similar whine. Replacing the fluid helped some.
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Old 08-27-2013, 11:27 AM   #3109
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The bar transfers motion across the front arms. If only one arm is moving, the bar will transfer energy to the other arm. If they are both moving identically, the bar will not flex - it will simply pivot along with the arms.
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Old 08-27-2013, 11:44 AM   #3110
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Quote:
Originally Posted by AustinTX View Post
The bar transfers motion across the front arms. If only one arm is moving, the bar will transfer energy to the other arm. If they are both moving identically, the bar will not flex - it will simply pivot along with the arms.
I'm probably noticing uneven compressions then.
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Old 08-27-2013, 02:54 PM   #3111
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Quote:
Originally Posted by wrxsomeday View Post
Finally watched your video, and that's quite a bit of whine. Pretty sure that's not from stiffer trans/motor mounts...but I have a good idea of what it might be.

When was the last time you changed your power steering fluid? Subaru's are notorious for power steer pump noise, and even brand new GR's have the issue. The root cause is that the power steer pump and lines are very close to the hot turbo and exhaust, which heats the fluid and rapidly fatigues the PS fluid. The solution is more frequent power steer fluid changes and/or adding a power steer fluid cooler.

My 08 STI had a very similar whine. Replacing the fluid helped some.
Interesting. I'd read something about the p/s being problematic on GRs somewhere before, but kind of forgot about it. Any chance it's related to the switch to stretch belts on the GRs?

I haven't had any issues with mine, but I'll pay more attention to it now.
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Old 08-27-2013, 03:06 PM   #3112
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Quote:
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I'm probably noticing uneven compressions then.
Not necessarily. It's unlikely that you hit the bump perfectly square and that the bump has the same profile across it. For example. If you hit a speedbump perfectly square, the sway bar doe very little, as both wheels move the same distance at the same time. But if you hit the speedbump at an angle or go around the outside of it with one wheel, the wheels move at different times/distances, inducing a twist in the bar, which will be felt as increased stiffness.

You also have stiction between the bar and bushings, but that should be pretty minor.
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Old 08-28-2013, 09:11 AM   #3113
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Safe travels and GL to all those heading out to Lincoln, I'll be out Tuesday for some seat time Wed, and fingers crossed for a good rookie showing Thurs/Fri.
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Old 08-31-2013, 12:18 PM   #3114
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I'm an autocross & STU noob... Just want to know if an STU prepped GD STi will have any reliability issues. My STi is my daily driver & I need to keep her reliable.
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Old 08-31-2013, 05:54 PM   #3115
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I've been running my '04 in STU since 2006. I used to drive it all over the midwest for a field engineer job as well. It isn't a daily driver now, but it is still capable of daily driving at 188,000 miles. The only reason it isn't anymore is that I was getting pretty serious about its competitiveness and some of the longer stretches were just a bit uncomfortable, so I bought a car to do the longer drives (about 6 months before getting laid-off from that job too).

In that time, it has gone through 2 clutches, a radiator, a front axle, a burned valve @153K, a turbo, a PS pump, and a crapload of tires. Everything else has either been maintenance or a performance upgrade.

Just keep it current on maintenance and fix things that do break correctly. It will be fine.
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Old 09-01-2013, 06:10 AM   #3116
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Quote:
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I'm an autocross & STU noob... Just want to know if an STU prepped GD STi will have any reliability issues. My STi is my daily driver & I need to keep her reliable.
It's like any car I feel, Take care of it and it will last. Alot of local non-autoxers(stance brotards) have been blowing motors by me left and right. Now my 05 Sti sees about 2 autox events a month and numerous track days throughout the year and so far it has held up just fine. With regular oil changes, fluid changes and thorough maintenance. A few extra bucks now will save you a ton of extra bucks later.

Last edited by gixxer7fiddy; 09-02-2013 at 10:33 PM.
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Old 09-09-2013, 03:28 PM   #3117
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Well, nationals was awesome. Great work by Josh to get the 2nd spot in STU. I'm pretty happy to still make the podium, though Geoff still showed us the way around. At least a BMW didn't win this year!

John
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Old 09-09-2013, 04:31 PM   #3118
DougM
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Well, nationals was awesome. Great work by Josh to get the 2nd spot in STU. I'm pretty happy to still make the podium, though Geoff still showed us the way around. At least a BMW didn't win this year!


and congrats everyone!
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Old 09-09-2013, 04:39 PM   #3119
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Next year should be interesting. I had a great car to drive in espl this year (thanks again Karen), but at this point have plans to run stul next year with my car. Maybe the grid will look a lot like esp/l.
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Old 09-09-2013, 05:58 PM   #3120
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One thing I noted as being odd....

With the exception of 1 EVO on BFGs and 2 STIs on Bridgestones and Hankooks, all the EVOs were on Dunlops, while all the STIs were on BFGs. 17 of the top-18 cars adhered to this pattern.

Hmmm....
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Old 09-09-2013, 10:34 PM   #3121
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Quote:
Originally Posted by Splash View Post
One thing I noted as being odd....

With the exception of 1 EVO on BFGs and 2 STIs on Bridgestones and Hankooks, all the EVOs were on Dunlops, while all the STIs were on BFGs. 17 of the top-18 cars adhered to this pattern.

Hmmm....
Subaru owners like koolaid?
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Old 09-09-2013, 11:16 PM   #3122
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Well, it sure looks like they all liked contingency...
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Old 09-09-2013, 11:28 PM   #3123
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We are all 'hoodrich?
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Old 09-10-2013, 12:48 AM   #3124
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How did any of you that ran the bfg's like them in Lincoln? I know a few of my STX buddies hated the bfg's.
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Old 09-10-2013, 01:36 AM   #3125
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Well, so far, I'm not a fan of them on asphalt or Wilmington concrete. I haven't been to Lincoln yet. That said, there are folks winning on them, so they can't be slow for everyone.

Who knows... Perhaps Josh would have had no free tires, but his trophy would have said "1st" if he'd have run Dunlops...
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