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991 Turbo front sway bar issues & 19" wheels rubbing
I recently purchased a 2014 991 Turbo and have performed the following upgrades
-Overall Suspension *Tractive Coil Overs * DSC V3 - Front Suspension: * Tarett Pro Series Front Lower Control Arms * Tarett Adjustable Tie Rods * Tarett 10m Axle Spacer's * TPC Front Sway Bar and Drop Links - Rear Suspension * Tarett Engineering Rear Control Arm Inner Monoball Bearing Rear Control Arm Outer Monoball Bearing Rear Forked Control Arm Monoball Bearing Rear Monoball Bearing, Toe Link Rear Upper Control Arm Link, Long *TPC Rear Sway Bar and Drop Links - Tires & Wheels * Wheels: 19" Signature Track Series * Tires: Hoosier R7 265 & 325 - Brakes * Currently on OEM Rotors with Yellow Pagids. Looking to upgrade the breaks later on. I decided to focus on the handling first then deal with the rest later. With that said i have ran into several issues. Some which i have read int he forum and not sure if there is a solution. - The first is with the front sway bar. See pictures attached. We have tried everything but it still rubs the front axle. I have it at its softest setting. I have spoken several times with the guys at TPC who have tried to help. THe latest i heard is that this type of setup doesn't allow you to turn the wheel 100% without the bar rubbing. Has anyone else found this issue? I know that Tarett offers different droplinks on the 997 TT but haven't been able to find anything online regarding the 991's. - Second issue is the rear lower wishbone is rubbing the inner wheel under heavy loading. We shaved a bit of off it in order to make sure there was art least a 5mm space between the wheel and the metal but its still rubbing. Called the wheel manufacturer as my shop said the wheel just has too bend and doubts that they are Forged as advertised but can't get any answer from anyone. I was sucked into buying these wheel by the old shop that was helping me and now i think it was a big mistake. Has anyone been able to properly correct this issue. Would hate to have to buy new wheels and still have the same problem still. - Third issue has been with the DSC Box or the Tractive Suspension. With all of the other issues i haven't really been able to really focus on this but first impression was that the shocks where way too soft for the springs and the car would bounce around all over the place. We then switch the DSC Box for the PASM and it took most of it away but made it of course pretty stiff at that point. Still wasn't supper stiff per say but the ride was then much more firmer. I was able to download the software and make some modifications to the DSC Box (essentially just stiffen the shock rates) and made it much better but still find that the car bounces around when i hit a bump and i'm either under heavy braking or cornering. It almost feels like putting really stiff springs on an old Cadillac and the car just keeps bounding after the first shock. Has anyone deal with this? Didn't seem to do it on the track, but again i only drove Sebring and was only able to do one and half session because of all the other issues. So most of the other stuff that i'm feeling is on street driving while the car is not being pushed. Sorry for all the rambling but i have now taken the car to three different shops bought alot of suspension parts and don't feel that i'm making much improvements. Luckly i found a really good shop now they just have never worked with any of the TPC Suspension stuff. https://cimg1.ibsrv.net/gimg/rennlis...2b1014c10d.jpg https://cimg0.ibsrv.net/gimg/rennlis...486e87fa7a.jpg https://cimg2.ibsrv.net/gimg/rennlis...e394ce8081.jpg https://cimg4.ibsrv.net/gimg/rennlis...23284166ae.jpg https://cimg9.ibsrv.net/gimg/rennlis...b6d069db19.jpg https://cimg3.ibsrv.net/gimg/rennlis...3ac40fcd06.jpg |
991 Turbo rubbing
I think you said it, a lot of aftermarket unsprung suspension components not harmonizing. Maybe something simple, faulty metallurgy, mismatched parts, sway bar/ drop link tension?
Back in the day, PCA racing infancy, one of the fastest GT1 cars own/oper. by independent P car race/service shop could not keep the car on track, medium speed lazy slow motion spins. After countless hours, setups, adjustments, etc. one weak mismatched spring was the cause. Good luck. |
I know TPC does great products, but honestly changing the front sway bar is totally unnecessary, especially with the V3 fitted. I would get rid of it quickly. Been racing my car for over a year in many different environments and it is very competitive with stock bar, initially it was simply lowered with Eibach springs, and now with full racing suspension and no PASM...stock sway bars. I run the same 19" wheel and tire size setup, and also the Tarrett bits and others. My OZ initially rubbed a little and it was apparent on the wishbone but its gone once the wishbone gave in some minimal thickness.
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I'm not sure about the fit of the TPC front bar, but it looks similar to ours. With the suspension hanging, the bar should be close to or lightly touching the control arm. It moves up and away as the suspension gets compressed, so make sure you have enough clearance to not contact the axle under compression. It looks like you are close to running out of drop link adjustment, so you may need to get longer ones to provide the safe axle clearance needed.
Ira |
For the record, I've been in contact with the OP.
1) The front sway bar- since the 996 Turbo/C4 days it has been a little bit of a challenge using GT3-shaped adjustable front sway bar on Turbo/C4 cars needing tight turning radius. This challenge carries on in the same manner from the 996 to 997 to 991 Turbo/C4 since the positioning of the front axle to the control arm to the drop link is similar. The issue usually presents itself when turning more than a full turn of the steering wheel from center, which then the gap closes between the links and front axle. Some companies make a curved drop link in an effort to increase the clearance when making a tighter turn. Tarett Engineering now offer a very nice and effective extension kit for Tractive dampers. https://cimg7.ibsrv.net/gimg/rennlis...900e14b79d.png We did install a Tarett extended drop link kit recently on a 997TT and we were impressed by the turning radius it offers on Turbo/C4 cars. Here are some pics. https://cimg0.ibsrv.net/gimg/rennlis...cd2fccc664.jpg https://cimg1.ibsrv.net/gimg/rennlis...ed54070f9f.jpg https://cimg9.ibsrv.net/gimg/rennlis...361d1025bf.jpg Note: The pic directly above show contact on the axle. The contact is not from the Tarett link, it was from the old link that was on this car for 9 years. I made a made an assumption on sending the OP our standard race links thinking the tighter turns won't be an issue on a mostly track car. For example, Cup cars are limited by the steering rack have to three-quarter turn of the steering wheel from center. And most track car customers have been fine with one full turn of the steering wheel from center. In this particular case I made a bad assumption. I will work with the OP to resolve. 2) Aftermarket wheel rubbing stock control arm- sorry I have nothing useful to contribute since I don't know the wheel. 3) DSC tuning too soft- this is an easy fix, I can email a stiffer mapping. The current DSC file does command up to 100% damping force to higher loads, usually its the initial turn-in that some users feel is too soft. In the DSC active command this is done on purpose to "set" the tire then as the tire loads up and g-force increases the damping command increases to the load. The mapping can be easily changed to start at a higher damping rate or get to 100% sooner or both. |
Tom, i saw saw that you called today. I will call you tomorrow to catch-up. I see the pics on the drop links from Tarett. Does these fit the 991 as well? I will check with Ira as well and double check his comment on the sway bar position. Trying to schedule a test day next week to try to solve some of these issues. (hopefully it doesn’t rain). Also regarding the DSC Box I’m trying to see how to record what’s going on so that I can send you guys the actual data of what we are feeling. The guys down here are checking in with the wheel manufacturer but my guess is that I might have to buy a new set from a different company. Want to try to make sure the issue does not persist thereafter. Could ride height / alignment be a contributor? I know that they setup the car similarly to what how they setup their cup cars. |
pdtp#16,
Point 1) As stated by TPC, there is very little room to play with an adjustable front sway bar in the way the front axle sits in the 996, 997 and 991 AWD cars. Unfortunately, the Turbo doesn't have PDCC, PDCC is magic. I have PDCC in my 991 Turbo S and conventional sway bars in my 991 GT3 RS. If you mount the top of that front drop link in an offset (with a spacer), it will allow you to eliminate rubbing, but you won't be able to use full stiff or one from full stiff on that sway bar. Also that drop link looks awfully short, you need at least another 3" on the drop link. Point 2) The only 19" wheels that clear the rear suspension of the 991 (GT3 or Turbo) are these two brands: Forgeline and Finspeed. Finspeed was under some internal business conflicts and were delayed a little bit in Production. Additionally, even with these two wheels, if running Sebring on a mega heavy car and with all those bumps, the rear wheels are going to deflect, and the tolerances are pretty small. However, the quality of forging on these two brands (and their big inner drum size given the 19" diameter) is what makes them suitable for the 991 with Rear Wheel steering (RWS is what changes the location of rear suspension arms making 19" wheels challenging to fit). You can also replace the bolt on that rear lower arm with the version on the Panamera, or trim down the head of the bolt just a tad, and make sure that the bolt head had its flat portion parallel to the ground (the hexagon shape of the bolt head as you would draw an hexagon on paper). Hoosier just released 20" tires. The 265 and 335 R7 will work perfectly with the AWD system and F/R wheel ratios in the 991 Turbo. In my Turbo S I ran 235/345, 265/345 and 295/345x19" (this last set was rubbing on the springs and requires rolling fenders and/or a new suspension with narrow springs). On 20" Hoosiers you gain an extra 12.7mm (1/2") of clearance on the rear suspension arm, and you could locate used 20" wheels a lot easier, as 991 GT3 and 991 Turbo wheels are all over the place, including a few affordable (but not that stiff) options from OZ. Point 3) Just look at how much time Pro and Am team spend at Sebring tuning the suspension, and they always run out of time. Fly a shock engineer to Florida, pay for the weekend of tuning, get someone familiar with Tractive shocks and a DSC. Your settings for Sebring will only work for Sebring, every other track is different (even same track at different days). Then there is the factor (the most important) on where is the driver's driving level. Pick up a track with easier access (PBIR) then get baselines for lap times, then get a Pro driver and a Coach (2 different people), the Pro to see what the car can do, the Coach to interpret the Pro and your data, and help you get better. If a Pro gains 1 second per minute of track time on me (given the same car) I'm happy with my performance, but if the gap is 2+ secs per minute, I have a lot of work to do, and that work needs a 3rd party (Coach) as the path of self-improvement and self-correction without external help can be simply eternal. |
Originally Posted by A/S
(Post 15057384)
Hoosier just released 20" tires. The 265 and 335 R7 will work perfectly with the AWD system and F/R wheel ratios in the 991 Turbo. In my Turbo S I ran 235/345, 265/345 and 295/345x19" (this last set was rubbing on the springs and requires rolling fenders and/or a new suspension with narrow springs). On 20" Hoosiers you gain an extra 12.7mm (1/2") of clearance on the rear suspension arm, and you could locate used 20" wheels a lot easier, as 991 GT3 and 991 Turbo wheels are all over the place, including a few affordable (but not that stiff) options from OZ.
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Originally Posted by Randyc151
(Post 15057455)
Do those Hoosiers fit the standard OEM TTS wheels? If your car is lowered, do you experience any rubbing?
You could also get custom made 20" with offset 45mm for center lock, make them 20x9.5 instead of 20x9, then no spacers needed and 265 fits under the fender. If going custom, get a 12"x20" for the back and make it same as stock offset (56mm), I would rather do a 51mm offset as the stock rear wheels stick a little too much under the rear fenders). Hoosiers have massive grip compared to any street rubber, and these tires have been engineered for full track use, so they are strong (construction and consistency). No rubbing, and my car is very lowered ( and re-indexed on corner weights and geometry for bump steer, thanks to KW and some bushings), it is lower than my 991 GT3 RS and my RS is maxed out lowered at the back, and set in the front to match factory rake. |
Originally Posted by A/S
(Post 15057684)
If you have center locks, you're out of luck, the front 265x20 R7 needs a 6mm spacer to not rub on the stock springs, but you can run the 245/35R20 R7 with the 335x20 in the back on stock 991 Turbo S center lock wheels (I don't know why Hoosier called it a 335x20 when it truly is a 315). The advantage of the 265 is that it reduces the understeer the car has on slow or tight turns.
You could also get custom made 20" with offset 45mm for center lock, make them 20x9.5 instead of 20x9, then no spacers needed and 265 fits under the fender. If going custom, get a 12"x20" for the back and make it same as stock offset (56mm), I would rather do a 51mm offset as the stock rear wheels stick a little too much under the rear fenders). Hoosiers have massive grip compared to any street rubber, and these tires have been engineered for full track use, so they are strong (construction and consistency). No rubbing, and my car is very lowered ( and re-indexed on corner weights and geometry for bump steer, thanks to KW and some bushings), it is lower than my 991 GT3 RS and my RS is maxed out lowered at the back, and set in the front to match factory rake. |
Originally Posted by A/S
(Post 15057384)
pdtp#16,
Point 1) As stated by TPC, there is very little room to play with an adjustable front sway bar in the way the front axle sits in the 996, 997 and 991 AWD cars. Unfortunately, the Turbo doesn't have PDCC, PDCC is magic. I have PDCC in my 991 Turbo S and conventional sway bars in my 991 GT3 RS. If you mount the top of that front drop link in an offset (with a spacer), it will allow you to eliminate rubbing, but you won't be able to use full stiff or one from full stiff on that sway bar. Also that drop link looks awfully short, you need at least another 3" on the drop link. Point 2) The only 19" wheels that clear the rear suspension of the 991 (GT3 or Turbo) are these two brands: Forgeline and Finspeed. Finspeed was under some internal business conflicts and were delayed a little bit in Production. Additionally, even with these two wheels, if running Sebring on a mega heavy car and with all those bumps, the rear wheels are going to deflect, and the tolerances are pretty small. However, the quality of forging on these two brands (and their big inner drum size given the 19" diameter) is what makes them suitable for the 991 with Rear Wheel steering (RWS is what changes the location of rear suspension arms making 19" wheels challenging to fit). You can also replace the bolt on that rear lower arm with the version on the Panamera, or trim down the head of the bolt just a tad, and make sure that the bolt head had its flat portion parallel to the ground (the hexagon shape of the bolt head as you would draw an hexagon on paper). Hoosier just released 20" tires. The 265 and 335 R7 will work perfectly with the AWD system and F/R wheel ratios in the 991 Turbo. In my Turbo S I ran 235/345, 265/345 and 295/345x19" (this last set was rubbing on the springs and requires rolling fenders and/or a new suspension with narrow springs). On 20" Hoosiers you gain an extra 12.7mm (1/2") of clearance on the rear suspension arm, and you could locate used 20" wheels a lot easier, as 991 GT3 and 991 Turbo wheels are all over the place, including a few affordable (but not that stiff) options from OZ. Point 3) Just look at how much time Pro and Am team spend at Sebring tuning the suspension, and they always run out of time. Fly a shock engineer to Florida, pay for the weekend of tuning, get someone familiar with Tractive shocks and a DSC. Your settings for Sebring will only work for Sebring, every other track is different (even same track at different days). Then there is the factor (the most important) on where is the driver's driving level. Pick up a track with easier access (PBIR) then get baselines for lap times, then get a Pro driver and a Coach (2 different people), the Pro to see what the car can do, the Coach to interpret the Pro and your data, and help you get better. If a Pro gains 1 second per minute of track time on me (given the same car) I'm happy with my performance, but if the gap is 2+ secs per minute, I have a lot of work to do, and that work needs a 3rd party (Coach) as the path of self-improvement and self-correction without external help can be simply eternal. Do you by chance know the part number to the Panamera bolt you are referring to? |
Originally Posted by nolimits
(Post 15059152)
This is exactly what I've been waiting to hear more about. So you are running 265/335 20" R7 with no rubbing or issues in stock TTS 991.1 or 2, wheel wells? Most aftermarket wheels start w 9.5 x 20 and 12 x 20. Offsets were my question and whether it could all work. I have suspension done w lots of camber and adjustability, axel extension up front, OEM CL wheels etc. OEM ride height and DSC set up very firm in Sport + for track. What exactly are you running now that is proven and works? Your track background and experiences would be helpful to hear more about. Good discussion for Tracking the Turbo thread. Thanks in advance.
http://www.yokohamawheel.jp/brand/ad...x_porsche.html |
Originally Posted by nolimits
(Post 15059152)
This is exactly what I've been waiting to hear more about. So you are running 265/335 20" R7 with no rubbing or issues in stock TTS 991.1 or 2, wheel wells? Most aftermarket wheels start w 9.5 x 20 and 12 x 20. Offsets were my question and whether it could all work. I have suspension done w lots of camber and adjustability, axel extension up front, OEM CL wheels etc. OEM ride height and DSC set up very firm in Sport + for track. What exactly are you running now that is proven and works? Your track background and experiences would be helpful to hear more about. Good discussion for Tracking the Turbo thread. Thanks in advance.
If you're on Center Lock stock wheels, your only Hoosier choice is 245x20 front and 335x20 rear. Again, the 335 is truly a 315 in size. No rubbing, just set front camber at -3.5 and rear camber at -3.0 and keep the same toe settings as stock (same for rake). I'm a certified track instructor with PCA and NASA at national level, with over 500 track days in a large variety of cars. |
Originally Posted by Tay101
(Post 15059262)
Here is a start with the 20x9.5 fitment. Advan makes their GT in that size and they state that it fits the front of the Turbo. They list the offset at +45. I am not sure how it fits as they also offer a 20x9 with the same offset:
http://www.yokohamawheel.jp/brand/ad...x_porsche.html The front 20x9 and 20x9,5 ET45 would fit perfectly, I prefer the 9.5 as the 265 tire would fit better. The rear that works is the 20x11.5 ET55. That 20x12ET44 is fine for the 991GT3RS but it will stick out beyond the rear fenders on the 991 Turbo S (I have a set of 19x12 ET46, the stick out 10mm too much in my 991 TTS and they could be 10mm more aggressive in offset in my 991GT3RS). Although, Forgeline and Finspeed can make awesome wheels here in U.S. Personally, Forgeline is my preference. |
Originally Posted by A/S
(Post 15059422)
This is Gold!!! where can we buy these wheels?
The front 20x9 and 20x9,5 ET45 would fit perfectly, I prefer the 9.5 as the 265 tire would fit better. The rear that works is the 20x11.5 ET55. That 20x12ET44 is fine for the 991GT3RS but it will stick out beyond the rear fenders on the 991 Turbo S (I have a set of 19x12 ET46, the stick out 10mm too much in my 991 TTS and they could be 10mm more aggressive in offset in my 991GT3RS). Although, Forgeline and Finspeed can make awesome wheels here in U.S. Personally, Forgeline is my preference. |
I have the Forgeline GA1R on 19", they are lighter than the $30k magnesium offers in the Weissach packages or the 991 Turbo S Exclusive, on my GT3 RS these GA1R wheels/tires removed 27 lbs of unsprung weight.
The easy button is 20x9.5" ET 45 (6mm more agressive than stock, but gaining enough inner space for the 265x20 Hoosier, no need to roll fenders, no rubbing either) front and 20"x12" ET56 (same offset as stock, just 0.5" wider). Forgeline are super strong wheels, stronger than any stock wheel. |
Originally Posted by A/S
(Post 15059422)
This is Gold!!! where can we buy these wheels?
The front 20x9 and 20x9,5 ET45 would fit perfectly, I prefer the 9.5 as the 265 tire would fit better. The rear that works is the 20x11.5 ET55. That 20x12ET44 is fine for the 991GT3RS but it will stick out beyond the rear fenders on the 991 Turbo S (I have a set of 19x12 ET46, the stick out 10mm too much in my 991 TTS and they could be 10mm more aggressive in offset in my 991GT3RS). Although, Forgeline and Finspeed can make awesome wheels here in U.S. Personally, Forgeline is my preference. Not to take anything away from other wheel manufactures like Forgeline and Finspeed as their quality is excellent and I had Forgeline's on my 964 and I currently have Finspeed's on my 2016 Viper ACR Extreme, but Rays, along with BBS, are at another level when it comes to wheels. I had these wheels on my GTR and the quality is amazing. Not only are the wheels of the highest quality, but they are cheaper than most of the other forged wheels out there. There are a lot of distributors for these wheels in the U.S., the three biggest I can think of are: http://www.evasivemotorsports.com https://www.vividracing.com https://www.ravspec.com |
Originally Posted by A/S
(Post 15059835)
I have the Forgeline GA1R on 19", they are lighter than the $30k magnesium offers in the Weissach packages or the 991 Turbo S Exclusive, on my GT3 RS these GA1R wheels/tires removed 27 lbs of unsprung weight.
The easy button is 20x9.5" ET 45 (6mm more agressive than stock, but gaining enough inner space for the 265x20 Hoosier, no need to roll fenders, no rubbing either) front and 20"x12" ET56 (same offset as stock, just 0.5" wider). Forgeline are super strong wheels, stronger than any stock wheel. |
If you use the stock offset and run a 265, when the car compresses the 2nd ring on the bulky springs (normally under heavy braking), the springs will rub the inside tire sidewall. The 6mm extra spacing from running ET45 fixes the problem. The won't rub at offset 51mm until you get the front suspension to work hard. Any caster will work (I have adjustable caster via offset bushings), but maxed out front caster is 8.8 degrees, unless I install split LCA then add shims, but snapping a front axle from the wheel carrier is not something I want to deal with (there are axle spacers, but I don't want to have an opinion on the massive torque the front axle handles on turn exit and those spacers not keeping up).
I run the much wider (still do) 345x19 Hoosier in the back, my rear fenders are pristine and untouched, despite of using a rear ET46 (I went a little aggressive on the offset because I was planning on sharing the wheels with the GT3 RS, so I needed a happy medium). 12x20 ET56 will works perfect and you can fit that 315 R7 that Hoosier wrongly labeled 335. By the way, on any racetrack I have driven, my 991 Turbo S produces better lap times than my 991.1 GT3 RS, but having a lightened TTS, massive extra power, and proper geometry/spring rates/bushings builds the TTS into one of the fastest road course cars (it is also good for drag racing, haven't done any official 1/4 mile pass but have done plenty of VBox runs). |
Originally Posted by A/S
(Post 15057384)
pdtp#16,
Point 1) As stated by TPC, there is very little room to play with an adjustable front sway bar in the way the front axle sits in the 996, 997 and 991 AWD cars. Unfortunately, the Turbo doesn't have PDCC, PDCC is magic. I have PDCC in my 991 Turbo S and conventional sway bars in my 991 GT3 RS. If you mount the top of that front drop link in an offset (with a spacer), it will allow you to eliminate rubbing, but you won't be able to use full stiff or one from full stiff on that sway bar. Also that drop link looks awfully short, you need at least another 3" on the drop link. Point 2) The only 19" wheels that clear the rear suspension of the 991 (GT3 or Turbo) are these two brands: Forgeline and Finspeed. Finspeed was under some internal business conflicts and were delayed a little bit in Production. Additionally, even with these two wheels, if running Sebring on a mega heavy car and with all those bumps, the rear wheels are going to deflect, and the tolerances are pretty small. However, the quality of forging on these two brands (and their big inner drum size given the 19" diameter) is what makes them suitable for the 991 with Rear Wheel steering (RWS is what changes the location of rear suspension arms making 19" wheels challenging to fit). You can also replace the bolt on that rear lower arm with the version on the Panamera, or trim down the head of the bolt just a tad, and make sure that the bolt head had its flat portion parallel to the ground (the hexagon shape of the bolt head as you would draw an hexagon on paper). Hoosier just released 20" tires. The 265 and 335 R7 will work perfectly with the AWD system and F/R wheel ratios in the 991 Turbo. In my Turbo S I ran 235/345, 265/345 and 295/345x19" (this last set was rubbing on the springs and requires rolling fenders and/or a new suspension with narrow springs). On 20" Hoosiers you gain an extra 12.7mm (1/2") of clearance on the rear suspension arm, and you could locate used 20" wheels a lot easier, as 991 GT3 and 991 Turbo wheels are all over the place, including a few affordable (but not that stiff) options from OZ. Point 3) Just look at how much time Pro and Am team spend at Sebring tuning the suspension, and they always run out of time. Fly a shock engineer to Florida, pay for the weekend of tuning, get someone familiar with Tractive shocks and a DSC. Your settings for Sebring will only work for Sebring, every other track is different (even same track at different days). Then there is the factor (the most important) on where is the driver's driving level. Pick up a track with easier access (PBIR) then get baselines for lap times, then get a Pro driver and a Coach (2 different people), the Pro to see what the car can do, the Coach to interpret the Pro and your data, and help you get better. If a Pro gains 1 second per minute of track time on me (given the same car) I'm happy with my performance, but if the gap is 2+ secs per minute, I have a lot of work to do, and that work needs a 3rd party (Coach) as the path of self-improvement and self-correction without external help can be simply eternal. A/S thanks for your reply. 1) spoke at length with TPC. They are sending me the drop links and extension brackets from Tarett. Hopefully this solves the issues. As you said still will be limited To the amount of adjustability that is available. If this doesn’t work, then the stock bar will go back in as suggested before 2) unfortunately I made the mistake to choose, upon bad advice, a wheel manufacturer that is not well known. I originally was going to order Forgeline as I know these wheels have worked for others. We have testing the car next week at two different tracks and hopefully see if we can get the issues with the rubing fixed. If not, I need to make a decision on going with 19” or 20” wheels. What would you suggest since you have tried both? I liked that on the 19” I would have more versatility on tire options as well as some reduction in weight as compared to the 20”. I am running both axle spacers, since we have widened the front track, as well as 7mm spacer for the wheels (this was only needed since the wheels offset on the 19” rims was rubbing the springs) will probably not needed with properly sized wheel. 3) I agree 100% with you. Unfortunately have not been able to run the car the two times we have taking to the track due to different issues. At Sebring, I was only running the Tractive shock suspension and the DSC box with stock wheels and Trofeo R tires. Was only able to run 1 1/2 sessions during the day since it was raining, and ran into other setup problems. The car ran ok specially taking into consideration that I hadn’t driven Sebring since 2003. Was able to get the car running in the mid 2:25 not pushing the car too hard. I can see that with the right setup and properly driving the car these times will drop considerably. During this event is were I first felt the issue with the shocks. As you properly said Sebring you are jumping all over the place so I couldn’t really know if it was a setup issue or just the way the shocks worked. After this I sent the car to Champion Motorsport who then finished the installation of all of the other items (by the way they have been great in helping sort out all of the issues created by the previous guys) Went to PBIR to test the car but noticed that rubbing really as soon as I started getting to speed (5 laps into first run). After this his I took the 19” wheels of put in the stock wheels and stock tires and drove the car on the street for a couple of days just trying to see if I could spot other issues before sending the car back to Champion. During these two days is that we noticed the continuance rubbing of the sway bars and continue to experience the wiredness (random bounce in the suspension). In further looking into it with TPC we figured it could be a couple of things - shocks have not been zero out to the alignment done by Champion (much lower than stock) this could be creating an issue with the dampening settings - the initial settings of the DSC box was not setup for track purposes. So we are going to be making some initial changes. In summary, we have agreed to have Champion make all of the changes with the front sway bar that are needed and realigned the car. Once that is completed, we will zero the shocks and then record whats current happening when we go over bumps and send it to TPC. TPC will the. Help us setup a good baseline to address those issues hopefully after this we can head back and test the car again. Once we get the car in good working condition, I plan on doing exactly what you suggested. I did this many times in the past when I raced. I used to get someone who was very familiar with the specific track and have them help me setup the car and compare what I was doing vs them. Nothing helps more than learning from a good driver or teacher specially if they are familiar with the track and the type of car you are driving. Thanks again for for all of your help. With fingers crossed I hope to solve this initial gremlins by next weekend!! |
Originally Posted by A/S
(Post 15060891)
If you use the stock offset and run a 265, when the car compresses the 2nd ring on the bulky springs (normally under heavy braking), the springs will rub the inside tire sidewall. The 6mm extra spacing from running ET45 fixes the problem. The won't rub at offset 51mm until you get the front suspension to work hard. Any caster will work (I have adjustable caster via offset bushings), but maxed out front caster is 8.8 degrees, unless I install split LCA then add shims, but snapping a front axle from the wheel carrier is not something I want to deal with (there are axle spacers, but I don't want to have an opinion on the massive torque the front axle handles on turn exit and those spacers not keeping up).
I run the much wider (still do) 345x19 Hoosier in the back, my rear fenders are pristine and untouched, despite of using a rear ET46 (I went a little aggressive on the offset because I was planning on sharing the wheels with the GT3 RS, so I needed a happy medium). 12x20 ET56 will works perfect and you can fit that 315 R7 that Hoosier wrongly labeled 335. By the way, on any racetrack I have driven, my 991 Turbo S produces better lap times than my 991.1 GT3 RS, but having a lightened TTS, massive extra power, and proper geometry/spring rates/bushings builds the TTS into one of the fastest road course cars (it is also good for drag racing, haven't done any official 1/4 mile pass but have done plenty of VBox runs). |
OP If you have to buy a new set of 19” wheels now, I would say stick to your 20” stock wheels. If you go 19” you have a larger choice of tires of course, simply use 997 GT3RS/GT2RS wheel offsets/ sizes they fit perfectly. I have also wider front track and my car is lowered 25mm. I fit 265s wihout issues in the front, even full racing slicks 28/67 and 31/71 in the rear lowered 20mm. This with -3.8 camber. By the way there are many more high quality 19” wheel choices that don’t rub, you don’t have to stick to those brands. OZ is one example but there is more. |
Originally Posted by Pdtp#16
(Post 15061583)
- shocks have not been zero out to the alignment done by Champion (much lower than stock) this could be creating an issue with the dampening settings
- the initial settings of the DSC box was not setup for track purposes. So we are going to be making some initial changes. I think your car's ride height and sway bar setting need some adjustment. The DSC can be tuned for how each driver prefers the car to feel on corner entry, our standard setting is soft for the beginning of corner entry phase to optimize weight transfer and to "set" the tire, and then stiffens up relative to the rate of change of the g-force and for suspension travel velocity(where zero'ing the ride height sensors is important for a much lowered car). This soft initial damping command may feel unexpecting to drivers who are expecting the initial roll stiffness of a non-electronic track setup. It took me a few track events to get used that feel and trust that when I commit to the turn it will stiffen up. Of course the DSC can be adjusted to increase the minimum damping value to achieve more initial roll stiffness to driver preference. And without the ride height sensors being zero'ed to the DSC for the much lowered ride height the damping commands won't be ideal. The zero'ing procedure is easy, glad to talk you though when you at that point. And looking forward to help you tune remotely. Our car is pretty close to stock ride height. https://rennlist.com/forums/991-turb...itational.html https://cimg4.ibsrv.net/gimg/rennlis...da005261a6.jpg https://cimg1.ibsrv.net/gimg/rennlis...b51b1eb231.jpg https://cimg4.ibsrv.net/gimg/rennlis...8487cc5c92.jpg https://cimg6.ibsrv.net/gimg/rennlis...994bccb212.jpg |
Originally Posted by Tom-TPC Racing
(Post 15062188)
I am sorry to beg the differ, and wanted to clarify that the DSC is setup for track use on OEM PASM dampers and for Tractive dampers. The DSC mapping, the Tractive dampers, and the spring rates on your car are exactly the same as our own 991TT, which in its first competition outing took P1 at NOLA road course in the Optima USC challenge.
I think your car's ride height and sway bar setting need some adjustment. The DSC can be tuned for how each driver prefers the car to feel on corner entry, our standard setting is soft for the beginning of corner entry phase to optimize weight transfer and to "set" the tire, and then stiffens up relative to the rate of change of the g-force and for suspension travel velocity(where zero'ing the ride height sensors is important for a much lowered car). This soft initial damping command may feel unexpecting to drivers who are expecting the initial roll stiffness of a non-electronic track setup. It took me a few track events to get used that feel and trust that when I commit to the turn it will stiffen up. Of course the DSC can be adjusted to increase the minimum damping value to achieve more initial roll stiffness to driver preference. And without the ride height sensors being zero'ed to the DSC for the much lowered ride height the damping commands won't be ideal. The zero'ing procedure is easy, glad to talk you though when you at that point. And looking forward to help you tune remotely. Our car is pretty close to stock ride height. Regarding the file that’s weird as it matches the same that you have on the website dated 2017. I downloaded the one from may 2018 which was much better. I do still think its an issue with the overall settings of many of the different parts installed. It could also well be an issue with the way the rear schools were installed by the previous shop. Champion is going through them this week. We we are definitely lower than Mike’s car. See attached. https://cimg7.ibsrv.net/gimg/rennlis...4514709f8.jpeg https://cimg6.ibsrv.net/gimg/rennlis...f19974117.jpeg |
Originally Posted by nolimits
(Post 15061647)
Good info, I'd heard the C2 265s worked but rubbed at full lock. Was told caster could take care of it, will inquire further. Agree the TTS is a beast in the right hands, easy to leave GT3 RS and Cup chase. All about seat time and getting folks to get good instruction/coaching, more so than parts spending before the skill set is there.
The 265 MPSC2 N-Spec is wider than the new R7 265. |
Originally Posted by Pdtp#16
(Post 15061583)
Went to PBIR to test the car but noticed that rubbing really as soon as I started getting to speed (5 laps into first run). On my bone stock 2016 Z06, I ran a 1:27 (MPSC2 tires). Hot 100 degrees day, after lap 3 the car went limp and was being outrun on the back straight by a 405Hp C5-Z06. On my bone stock 991 GT3 RS (except side muffler deleted, Catless headers now removed, and proper corner weights, lowered and aligned to my specs) I ran a 1:23. My TTS on Trofeo-R, lowering springs and a stage2 powerkit a 1:23 too, and same TTS with Inconel headers/catless Inconel exhaust, tune for race gas, lightened (low fuel, Li-Ion battery and the massive reduction from the exhaust) same 245/305 trofeo-R (I have only used the tires 2 track sessions, they are for sale), the KW suspension, stiff front bushings, and properly corner weighed and aligned ran a 1:21. I haven't tried any of these cars on Hoosiers at PBIR, and I have Hoosiers for them all (I prefer a nice drive in the middle of the week, no trailer, just show up run a few laps, have dinner on the way back, then home). TTS is now dismantled from some of the power mods (sold a few, others for sale), as it may get traded for an Italian exotic. From the 3 cars above, the one I enjoy the most is the GT3 RS, the TTS produces better lap times (with the mods), but the GT3 RS is just fun and even if it went 6 secs slower at PBIR (like my Z06) it would still be my favorite. The TPC car (based on a 991.1 Turbo S) with the GT3RS Aero mods (and obviously lighter) plus the space to run wider front wheels/tires, and an even bigger wing than the 991RS must be a monster, it is one of my favorite street cars. |
Beautiful car TPC :thumbup: The 991.2 GT3/RS front bumper looks amazing.
Just surprised how high it is run in the rear, my 991 TT is setup by Manthey at 335mm center of the wheel to fender, this must be 15-20mm higher. Rake-wise, bit more aggressive than stock, handling is incredibly neutral with all, 19" Trofeo R, Hoosier R7 and Pirelli full racing slicks. |
The TPC car looks amazing. Just saw that they added a few new improvements!!! https://cimg7.ibsrv.net/gimg/rennlis...be4f3d035.jpeg |
Guys,
Was finally able to get the car working well enough to get to the track and put some time on it. Did about four 20 minute sessions at PBIR this Saturday. It was Hot!!! This is what we were able to gather. * Sway Bar - seems not to be rubbing anymore. However seems like we are limited to the two softest settings. Is this right? See picshttps://cimg0.ibsrv.net/gimg/rennlis...797b200d44.jpg https://cimg1.ibsrv.net/gimg/rennlis...ce1d112849.jpg https://cimg2.ibsrv.net/gimg/rennlis...753d482747.jpg * Wheel rubbing seems to have gone away * Suspension and DSC Box - Zeroing out the shocks made a huge difference. - Not sure if there was something wrong with the prior installation but in order to install some of the new rear parts we ended up taking all of the shocks outs and re-installing everything again. The combination of this and re-calibrating the shocks took all of the suspensions weirdness away - Did a bunch of different test runs. Tom I will send you the test files for your review. - With this now working we can focus on getting the right settings for the right tracks. But i believe we still have some work to do with alignment etc. before getting here. The guys at the shops used the following alignment as there baseline https://cimg7.ibsrv.net/gimg/rennlis...8aa71b1fca.jpg These are my impression from my four sessions - Other than the few laps I put in a few weeks ago at night, this was really my first time at PBIR. I ran Morosso quite a bit but never the new track. - So my first session was really as much as making sure everything was working well as getting familiarized with the track. - Once i got things going i found that i was struggling quite a bit with understeer and once the tires came up to temp i was sliding all over the place. I actually felt i had much more grip on the Trofeo's than the Hoosiers. We ended up lowering the tire pressures down to 30 front 32 rear (hot) and that seemed to neutralized things somewhat. Otherwise after 3 or 4 laps it felt like i was on a dirt track. - Another issue I found with all of the heat was I started getting break fade. With all of the work that has gone in the car i couldn't remember if they flushed the whole system since the last event. All in all it was a lot of fun to get out there and run the car even if i was expecting a bit more out of it. I was able to run in the lows 1.24's by fourth session. I'm sure with getting to know the track better (better lines etc), getting more confident on the breaks (specially turn 10 i was breaking really early) could have shaved another second or so. Hope that with better alignment, getting the car scaled, investing in some video / data login and some instruction I can get these times down. I wish i was taking her up north this summer. So i guess for now the car will go down to the shop to finish some of the rest of the build. Can't wait for this fall to get to track time back again. In the meantime she will go in a diet this summer and maybe get some exhaust and engine tuning!!! |
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