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Hey Gents, My car is in the home stretch of the 93 tune after having a Turbo build along with some other updates done (Lower painted bits w/Aerokit front spoiler were added, HRE P101 wheels/Michelin SC2 tires, 993RS motor mounts, and H&R Springs) at AutoQuest Motorsports in Ft. Myers, Fl. Anyway the owner, Gavin, spoke to me last nite with an update and noted that on his last test drive he took it down a certain section of road with a bump at "high speed" of about 45mph to 50mph that they use to check real world clearances and noted some scrubbing. They checked into it further and discovered the rear tires were just barely rubbing on the inside fender well over the "high speed" bump. To my subject, Gavin said they are familiar with this problem/fix and have a tool to Roll the inside of the inner fender, and that in my case it only required 4 or 5mm. A really nice solution that I thought I would pass along for others that may experience this in their lowered cars. I also wanted to say Thank You online in the forum to Gavin at AutoQuest MotorSports for his expertise and his determination that the car not be delivered until throttle delivery is as good as OEM and all other systems are nominal. During the tune there have been a variety of vacuum leak issues discovered; some manufacturing/assembly errors, some possible installation mistakes and some part issues but Gavin (along with Sam at ByDesign who is doing the 93 and E85 tunes along with providing consultation/guidance on troubleshooting TT vacuum leaks) and the AutoQuest Tech Jerome, have steadfastly worked the issues to solve the problems encountered and as I said Gavin's determination to not deliver a car that isn't perfect. It is taking longer than I/we expected but I am extremely thankful that the team is going to such lengths to deliver a high quality product. Edit: Please note my wheels and tires are both OEM spec'd size.
Why not install some dog bones at the rear during the lowering? That would fix the rubbing.
Was not aware of that option. This is my first P car and have only had her since August so I am not up to speed on the suspension components. AutoQuest assured me their alignment would be fine lowered without other components so I stopped there. Thanks for the info though, I will look into that down the road. What exactly are "dog bones", some sort of rear control arm?
What are your alignment numbers? A little more negative camber in the rear?
Go to Eastwood products or XYZ and get the Hub mounted wheel arch/fender roller..
i have H&R lowering springs on stock wheels and tires and experience no rubbing. I'd bet the HRE offsets are not exactly stock spec'd
Interesting...I am being told there are no spacers involved and as to the offset in the HRE wheels themselves, I would certainly expect $10,000 wheels to be spec'd correctly but I have not seen them yet. I was told the car was driving perfectly with no rubbing at all except for the high speed bump they use to test real world clearance when a slight sound was detected by the Owner, the tech hadn't noticed anything, so perhaps your car has just never experienced that level of compression. Anywho thanks for your insight, I appreciate that. I am just glad the Owner caught it and has experience with the rolling, he said no big deal they do it all the time in their race car builds and mine just needs a small 4 - 5mm roll in one area.
There are some tools you can use online if you had the wheel and tire information (wheel diameter, width, offset / tire width,ratio, diameter) that you can compare to stock and see what happens (pushes out, squeezes in, etc). I use them to determine if I need spacers or if the offset is out of range to use on the vehicle.
Lowering changes what the inside wheel well clearance will be, but from your description it sounds like an offset issue.
Certainly a call to HRE should set provide any missing information. That's a lot of coin not to have things the way they should be.
Was not aware of that option. This is my first P car and have only had her since August so I am not up to speed on the suspension components. AutoQuest assured me their alignment would be fine lowered without other components so I stopped there. Thanks for the info though, I will look into that down the road. What exactly are "dog bones", some sort of rear control arm?
This ridiculously high offset of the stock wheels puts the wheels WAY too far into the fender. Most (all?) aftermarket wheel companies either increase the width of the wheel or decrease the offset of the wheel to get the wheels flush with the fender. Often, even with a width increase, the offset is still decreased to get the outside of the wheel to sit flush with the fender (which can lead to rubbing when you lower the car). Assuming that is the case, I don't think anything was done improperly. However, any company making custom wheels should be asking if your car is lowered and recommend the appropriate offset for the width you want. Personally, I went from the stock 11" width rear wheel to a 12" width rear wheel and I still decreased the offset to 47mm from the stock 51mm. I did not lower my car and this allowed my Turbo S wheels to sit flush with the rear fender.
This ridiculously high offset of the stock wheels puts the wheels WAY too far into the fender. Most (all?) aftermarket wheel companies either increase the width of the wheel or decrease the offset of the wheel to get the wheels flush with the fender. Often, even with a width increase, the offset is still decreased to get the outside of the wheel to sit flush with the fender (which can lead to rubbing when you lower the car). Assuming that is the case, I don't think anything was done improperly. However, any company making custom wheels should be asking if your car is lowered and recommend the appropriate offset for the width you want. Personally, I went from the stock 11" width rear wheel to a 12" width rear wheel and I still decreased the offset to 47mm from the stock 51mm. I did not lower my car and this allowed my Turbo S wheels to sit flush with the rear fender.
Not trying to be critical here but you shouldn't control rear camber via dog bones on these cars, aftermarket dog links should be set to OEM length and used for the benefit of eliminating rubber only. Using them to adjust camber, based on their design can change the bump curve of the rear suspension and unless you're willing to buy adjustable bump steer components and have someone re-set the bump curve it's not advised. These cars are already touchy enough with rear alignment settings. I "guess" it's less critical on a street car if you throw the bump curve off a little but personally I wouldn't mess with it.....and yes I have aftermarket ERP dog bones on my GT3 track car and went through all of this myself the hard way.
The way to get more camber is to go to a 2 piece lower control arm and add shims.
That said...if someone knows how to roll fenders correctly without cracking paint there's no harm in doing so if you only need a couple mm of clearance.
Not trying to be critical here but you shouldn't control rear camber via dog bones on these cars, aftermarket dog links should be set to OEM length and used for the benefit of eliminating rubber only. Using them to adjust camber, based on their design can change the bump curve of the rear suspension and unless you're willing to buy adjustable bump steer components and have someone re-set the bump curve it's not advised. These cars are already touchy enough with rear alignment settings. I "guess" it's less critical on a street car if you throw the bump curve off a little but personally I wouldn't mess with it.....and yes I have aftermarket ERP dog bones on my GT3 track car and went through all of this myself the hard way.
The way to get more camber is to go to a 2 piece lower control arm and add shims.
That said...if someone knows how to roll fenders correctly without cracking paint there's no harm in doing so if you only need a couple mm of clearance.
Thank you for your insight and for your expertise regarding the suspension geometry. As to the Fender rolling, it is the inner fender well liner that they roll, apparently just in one area, so its not rolling the actual fenders (which as you say would take some real expertise to not affect the paint. p.s. Congrats on the GT3 track car...that is sweet!
Thank you for your insight and for your expertise regarding the suspension geometry. As to the Fender rolling, it is the inner fender well liner that they roll, apparently just in one area, so its not rolling the actual fenders (which as you say would take some real expertise to not affect the paint. p.s. Congrats on the GT3 track car...that is sweet!
Now I'm intrigued where they are rolling...cause you can't really roll the plastic liners. I've never paid too much attention to the fender wells of the turbo, maybe there's a seam (I know there's one in the GT3) and that's what it's rubbing on??? If it is just that seam...roll away without hesitation in my opinion. Gavin is good people, he maintains alot of my friends track cars when they ship them to FL for the winter.
FWIW have a 997.2 Turbo S...with 20x12 HRE's and 325 width rear tires and don't get any rubbing on my car. IDK what tires you have but Michelin's always have rounded shoulders which provide a little more clearance for the tires by default but again if we're talking about the seam inside the wheel well vs. the fender this won't matter.
On the 996TT and 997TT widebody with the upper side intake tube you have layers of sheetmetal that forms the inside wheel arch/lip This inside lip is rolled. The GT2 and GT3 have rolled lip from the factory>>they didn't do it for the turbo owners!
12-04-2018, 01:24 PM
Rolling the Rear Inner Fenders
