Tire Selection for NASA TT

Discussion in 'Corner Carver Racing Tech Discussion' started by ddd4114, Oct 4, 2018.

  1. ddd4114

    ddd4114 forum member

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    Just like almost everyone else in TT, I'm always looking for (relatively) easy ways to shave off a couple tenths per lap, and after finding little improvement with messing around with suspension setup, I'm tempted to reevaluate my tire selection. If you're interested in hearing my experience and "logic" for this, see the following wall of text. If not, you can skip to the Cliff's Notes at the end.

    First, some background to explain how I arrived at this point:

    I've been driving my 2011 GT in TT for a little over 4 years, and most of that time has been on Hoosier R7's. When I first started, I ran the car in TTB at ~3800 lb (including me), and I started on 275mm NT-01's. Soon after, I decided to shuffle points and try the "compound always trumps width" concept and switched to 245mm R7's. This isn't quite a fair comparison because a 245mm R7 is actually only 5-10mm skinnier than a 275mm NT01, but even still, I immediately dropped ~4 seconds per lap without any other changes. The 245mm R7's were definitely overloaded and noticeably lost grip in long braking zones, but they were surprisingly consistent for an entire 15 min TT session. Some of my best times were set on laps 4 or 5, which admittedly could just indicate incompetence. Lighter cars would destroy me in the corners (where I struggled to maintain more than ~1.3g), but I made up the difference with a lot of power, and it showed that the less-than-ideal setup at least had a fighting chance against prepped S2000's and STI's on more open tracks.

    Fast-forward to 2017, and NASA got rid of TTB. Knowing a 3800-lb Mustang would be cannon fodder in TT4, I moved to TT3. That allowed me to switch from 245mm R7's to 315mm R7's and go aero crazy. The 315mm R7's were definitely an improvement - by almost 0.1g, which is a lot. However, even with wider R7's, another 36whp, and hundreds of pounds of downforce, my lap times weren't *that* much better than in TTB. For example, my best Mid-Ohio Pro Course time was 1:36.5 in TTB, and now it's 1:33.2 in TT3 even with way more grip, more power (yet more drag), and more experience. Three seconds is a lot, but... I really struggle to compete with well-built Corvettes, and I don't give up easily.

    This summer, I made the switch from 315mm R7's to 315mm A7's. On R7's, even if I was aggressive on the warm-up lap, the first hot lap was always way off pace. Even pushing it, I would be 2 seconds off my lap 2 times, and typically there was still a little improvement on lap 3. As expected, the A7's were basically ready to go by the end of the wam-up lap, but I still noticed that my lap 2 times were at least 0.5 sec better than lap 1. That wouldn't be such a big deal, but there were two huge downsides of the A7: they were TOAST by lap 4 (if not sooner), and they were at the cords - and way more exciting to drive on - after 15 heat cycles when R7's would be good for 30 heat cycles. I would be somewhat accepting of these compromises if the A7 was much faster than the R7, but it wasn't. When I compared lap times and data to my recent events with R7's, there was basically no difference. Hoosier actually told me this would happen when I consulted them about tire selection a couple years ago, but since people always claim how much better A's are than R's, I had to try them. Who would have thought Hoosier would be right???

    Here is where I stand now:

    Since Hoosier has an excellent contingency program for TT, I'd really like to stick with their tires (no pun intended). I'm pretty convinced that a 315mm A7 is not a superior tire to a 315mm R7's with this much weight and aero loading. I talked with Vorshlag to see what would be required to run their 11"/12" wheel package - or better yet, a 12" square package - but it sounds like this will not be a bolt-on affair. I already need a 1/2" + 3mm spacer in the front to keep the coilovers from chewing the tires, and they already stick out of the fenders by ~1/2". Wider tires will actually be a considerable expense to do it right: flares, maybe spacers, new wheels, more expensive tires, maybe some inner fender clearancing... It's also certainly more drag. That got me thinking: if "compound always trumps width" worked in TTB, maybe it could work now...

    I looked into my point assessments for TT classification, and here are the two options I have:
    1) Keep running a DOT tire as wide as I want at 3751 lb min weight. Right now, I cross the scales at ~3800 lb, so a small diet wouldn't hurt.
    2) Switch to a non-DOT tire (probably an S80) no wider than 265mm and run it at 3831 lb min weight. Considering where I am now, this is really only another 40-50 lb with some buffer.

    I called Hoosier to ask about this, and they advised against running a smaller tire on this heavy of a car even for a short TT session. They also said a non-DOT tire will take way too long to warm up, but I was a little skeptical about that. The Pirelli DH compound is somewhat common in TT, and people seem to make them work even though they're designed to last WAY longer than a 15-min TT session and tend to heat up slowly. Also, everyone I've talked to said they provide a noticeable improvement in grip over an R7. I've also read on the internet (which MUST be true) that a Hoosier S80/S100 provides similar or more grip than a DH but doesn't last as long. My hope was that running an overloaded 265mm S80 would warm up within 2 hot laps and still provide more grip than an R7 - at least within a narrow window. For sure I'll be on the wrong side of the load sensitivity curve and a lighter car will get much more grip out of them, but as long as it's more than an R7 - even by 0.05g - it might be enough of an edge to justify the change if I can win tires through contingency. Speaking of - another downside of an S80/S100 is that they're ~$50 more per tire. Whatever the case, it would be silly to ignore Hoosier's advice about their own tire, but I also have to consider that I'm playing with a somewhat uncommon setup compared to most of their customers. I imagine that most of their experience is with much more restrictive classes, and I just need to make something work really well for 1-2 laps even if it sucks everywhere else.

    Cliff's Notes:

    What will provide more grip for just one lap of a 10-15 min TT session: a 315mm Hoosier R7 or a 265mm non-DOT slick (preferably a Hoosier S80/S100)?

    If anybody has experience with experimenting with things like this and is willing to share, I would definitely appreciate the advice. I know it wouldn't be difficult or expensive to test a set of used S80/S100 slicks or even Pirelli DH slicks, but since I don't know how much slower they would be compared to stickers, I'm afraid the test would be misleading.

    Thanks,

    Dan
     
  2. ApexRaceParts

    ApexRaceParts Official Site Vendor

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    There is no faster DOT tire than the Hoosier A7. One of our customers is considering making the switch to Pirelli DH slicks as they are faster and he could afford a slight weight penalty (he runs in ST2).

    If I were you, I would put 18x11" all around and run 315 A7's if it is in your budget. Otherwise, stick with the R7. Your car is already a bit heavy and I would not want to keep adding to that. We make 18x11" wheels that you can easily rotate which would extend the life out of the tires compared to something that uses different offsets front and rear.

    - Cory
     
  3. Vorshlag-Fair

    Vorshlag-Fair Official Site Vendor

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    Lots of good data presented by the OP. Let me take a crack at what he is doing vs what we did in a similar car in this class... edit: to the OP, the 3 second drop going to 315s is a HUGE improvement, btw! :)

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    We came up with the much copied 18x11 front and rear (plus a unique 18x12" rear wheel) package to fit the S197 back in late 2011. No giant spacers needed. If your suspension is setup halfway right you shouldn't need to rotate tires, but I don't know what the OP is using there. A picture of two might help.

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    The 18x12" rear is a fairly painless bolt on, as it doesn't require fender cutting of any sort. Just need to remove the chassis-side bump stop bracket (about 8 spot welds). But some people don't want to mess with that work, so we just tell them to use 18x11" rear wheels for this tire. My 2011 GT above is on 18x12's and 315/30/18 A6 tires.

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    Unless I missed it, did the OP ever say what wheels he is on? Or the suspension? I'm going to assume he is on 18x11's, but sticking 1/2 pas the fenders is unusual with our offsets, unless it has a strut that is very atypical. This is our 2011 GT on 18x11" fronts and 18x12" rears with the 315/30/18 Hoosier A6, shown above. #ZeroPoke If the OP has our wheels and this much poke, please email us at [email protected] so we can get to the bottom of that.

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    We noticed that the 315 Hoosier wore a bit better on the 12" wide wheels, which gave them a tiny stretch. Mounted to the 1" narrower 18x11" wheels they have the slightest squeeze. We ran the 2012-13 NASA seasons on this 18x11F/18x12R setup, first in TTS (2012) then in TT3 (2013). By 2013 we were always on the Hoosier A6 compound. We like the "A" vs the "R" as it allowed me to get my fast laps in on lap 1 rather than lap 3 or 4, by which time the front of the TT grid has caught the rear... and then you are fighting traffic.

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    Maybe your region isn't backed up like this, but in Texas we regularly see 45-70 cars in Time Trial. In TT3 we would usually sit in P3 to P5 on the grid. I'd tend to blast out for a flier, sometimes working out a deal with TT1 guys on Pirellis and other non-DOT slicks (that take longer to heat up) to let me by on the out lap, get my flier lap in, then let them pass me on hot lap 2, when I was doing a cool down lap and coming in.

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    Part way into the 2013 season we decided to move all four corners to the 18x12" wheels - using the same 315/30/18 Hoosier A6 (then later the A7).

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    Obviously this required us to cut the front fenders - but not the rears (which like I said, fit the 12s with just inboard bump stop removal). I purchased a new set of front fenders and kept the virgin OEM fenders in the attic, in case I ever reverted the car back to stock (we didn't). This was a modest investment but it looked ugly with just cut fenders.

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    With enough fender clearance to avoid cutting a tire at full bump, it worked, and we were faster like this - even with the tires sticking out in the air, looking terrible. We ran the rest of the 2013 NASA season like this.

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    We made flares to cover the front and top of the tire in the 2013 season, which smoothed airflow around the front of the car. We kept those 18x12s and 315s for the rest of that season and into early 2014.

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    We ran the majority of 2014-15 seasons with flared rear fenders, then stepped up to 335/30/18 front and 345/35/18 rear A7s. We saw an average drop of 2-3 seconds per track in lap times going with the big tires. We ran at 3802 lbs for maximum p-to-w ratio bonus in TT3, and in some seasons we ran 8.8 lbs per whp.

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    I'm still a believer in "run at the fat end" of the power-to-weight scale for any given p-to-w TT/ST class, running more weight to get the "Weight bonus", all to have more power than the rest of the field. On the S550 chassis, we have a bit less room out back and cannot seem to sneak in an 18x12" wheel, for now. The front is limited as well, but we have some fender options that might allow this 315m tire to be used on an 18x12". But we'd have to cut the rear fenders to fit that, and 335 or 345mm tires would require major mods/flares.

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    That's the choice the OP needs to make - if he wants to fight with Corvettes (the C6Z can swallow giant tires under stock fenders, see above) he is probably going to have to cut the fenders and GO BIG with tires, to reach parity. The 1.4g limit is all you are really going to see from mechanical grip with any tire, no matter how wide you go. The wider tires just deal with heat better and give you a slight advantage putting power down (esp. the 345/35/18).

    [​IMG]

    And R7 vs A7 has a lot to do with driving style (how fast can you get up to speed?) and your TT group's traffic tendencies (do you need to get it done on lap 1 or can you take your time and wait until lap 2, 3 or 4?).

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    Forgestar came out with an 18x13" wheel in 2015, and we love this thing. It is what we should have been running with that 345/35/18 rear tire, but it just wasn't available from them at the time. The price is attractive and the weight makes sense for how wide it is. You might wait a while for the "group buy" wheel company to get this one in production, ;) but these can be had relatively quickly from Forgestar.

    [​IMG] [​IMG]

    We have noticed longer life in the R7s, which I ran on two TT cars over the 2015-17 seasons. But they do take a number of laps to get up to operating temps, and it often led these cars into traffic situations. It was a lot more work for me to get clear track by lap 3-5, in both of these cars, and I missed the A7 advantage. But its not what everyone needs, I suppose...

    One last thing - we went up in spring rate with each increase in tire width (as well as with increasing aero load). If the OP could post a pic of the car loaded in a corner, it might tell us a lot. Again - more detail on the wheels, suspension, spring rates would help.

    Good luck,
     
    Last edited: Oct 8, 2018
  4. Norm Peterson

    Norm Peterson corner barstool sitter

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    How much negative camber are you assuming?

    While the 2011 fenders may be slightly different from mine, I just measured about 11mm of tire and wheel 'poke' with 11's at -1.9°, with 3mm spacers. 285/35 MPSS. No camber correction at the strut to knuckle.


    Norm
     
  5. ddd4114

    ddd4114 forum member

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    Thanks a lot for all the info!

    To address the questions about my car setup:
    • Terry, I'm using your (Vorshlag's) MCS double-adjustable shock setup. I REALLY like the shocks, especially compared to the Koni Yellows they replaced. However, since I'm running a really aggressive splitter, I'm also running really aggressive spring rates to keep it off the wear strips. I'm at 1100 lb/in front and 450 lb/in rear, and I've had MCS revalve the shocks to allow for a little more adjustment (I was running them near full stiff with the original valving). I'm also using the Whiteline adjustable sway bars on both ends. I have the front at full soft in an effort to maintain some level of independence, and I have the rear bar set at one "hole" from full stiff. I set the ride heights to ~26.75" at the center of the fender wells, which is ~4.25" at the back of the subframe. If I drop it any lower, it's hard to get a low-profile jack under the car, and aside from that, the front roll center is already nearing the center of the Earth, so why make the geometry even worse.
    • I'm using 18x10.5" PF01's with (I think) a 38mm offset. They're definitely not ideal for a 315mm Hoosier, and this is part of the reason for why I'm looking to make a change. However, wheels are expensive, so I'd like to make sure I have all the information I can get before making another purchase. If I can make a 265 non-DOT tire work for one magical lap, a 10.5" rim is pretty much what I need. Then, I'd try to find an affordable 11" square setup for "practice" tires. If that setup is a pipe dream, I think a move to 12" rims will happen in the future, especially if a 335mm+ R7/A7 seems like the way to go. If moving from a 315mm to a 335mm Hoosier is worth ~2 seconds, that seems like a no-brainer. I'm within 2 seconds of pretty much every TT3 track record in the region, and almost none of them have been beaten since a ridiculous Corvette set them back in 2013/2014. I wonder if that's just the right balance to make an A6/A7 work on a 3800-lb car, and a 315mm was just shy of working correctly. It could definitely be worth an experiment, but... it sounds like "some assembly required". I already cut my fenders for venting, so I guess what's a little more?
    • I'm running -3.7 deg of camber. I try to do most at the camber plates (but not all, just to allow for some adjustability), but I inevitably have to use some of the slotted hole on the top of the struts. I'm guessing I have them adjusted at ~1/3 of the way from the "minimum camber" position or whatever you call it. Adjusting camber that way adversely affects wheel clearance in a hurry, so maybe that's part of the reason for needing so much front spacer. However, even with them almost all the way angled outward, there wasn't a chance in hell of those wheels fitting on the front. The rear is basically a non-issue, but I still have infrequent tire-to-fender contact on bumpy tracks.
    • Regarding tire wear, I also notice that all corners tend to wear pretty evenly. However, I find that the outside-front tire seems to take the most abuse, and the inside-rear tire seems to take the least. Therefore, I rotate the wheels every weekend to keep the wear a little more even. Do I really have to do this? Probably not, but if I can get another 1-2 heat cycles out of them, it seems worth it. Tires aren't cheap if I don't win them.
    • Traffic in my region (Great Lakes) is typically managed pretty well by the middle of Saturday. We make an effort to bunch up on the out-lap to keep the faster cars from catching the back of the field as much as possible, so I can easily get 3 clean hot laps if the people in front of me keep up the pace, and 4 clean laps is not unusual. After that, I start catching traffic. We rarely see more than ~45 cars on the track, and most of the group has been driving in TT for years, so that definitely helps. We have everything from Faessler's ridiculous S550 to near-stock TTF cars, and there's still minimal issues with people playing nice.

    I don't have a lot of pictures, but these are from about two months ago, and they're near the apex of a low-speed turn:
    [​IMG]
    [​IMG]

    This is one is toward the exit of a high-speed turn a little later in the track, where I'm definitely 100% throttle:
    [​IMG]

    Like I said... I have a pretty aggressive front splitter. I got rid of the canards at the top of the end plates because I found they didn't add enough downforce to overcome the drag penalty, but otherwise it's the same. Even with swan-neck mounts, I'm running the massive 72"x14" AJ Hartman wing at 9-10 deg to keep the car balanced.
     
  6. Vorshlag-Fair

    Vorshlag-Fair Official Site Vendor

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    Good replies and more info to chew on. I love forums for the fact that we can all add more than ONE picture per reply (Facebook sucks!) and that this thread won't be lost by tomorrow (Facebook sucks!) ;)

    [​IMG]

    So we assume anyone running our 11" wide wheels is doing so for track/competition use (and we have conversations with anyone who orders wheels from us, and ask these very questions - these are not made for "daily driving" kinds of uses), therefor they are running real camber.... like -2.5 to -4.0° front. Anyone that thinks they need less than that, well, I have memes... ;)

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    Seriously, I want people to understand that a McStrut car with 1000# of static load on each front tire (S197 or S550), with lots of bushing compliance, and Hoosier levels of grip needs a LOT of static camber to keep the tread flat in the outside tires when loaded. We're seeing 1.4g lateral, 1.5g braking, and that moves a lot of squishy bits around!

    [​IMG]

    The picture above is a corner and we are still seeing negative camber under load. That's with -3.5 degrees and NO aero. The OP, with some real aero loading, should be running closer to -4.0° up front, I suspect.

    [​IMG] [​IMG]

    Which you might not be able to get with some ride heights at the limit of the towers... sometimes "you have to cut a b1tch." (of course i mean that in a non-gender-specific way)

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    We have fixtures for sale now to make this cut cleanly, centered, and painless. We have done this to dozens of S197 and now S550 chassis. It is necessary for additional camber travel "at the tower" and allows you to make more tire clearance at the strut-to-spindle location.

    [​IMG]

    And not knowing or seeing everyone's suspension up close, I can't say if their slotted junction is ideal or not. You have to realize how much movement there can be in the spindle to strut junction. This is an Ohlins strut on our S550, above and below. The AST and the MCS both had similar amount of slotted hole movement. There's no hard and fast rule of "all the way in" or "all the way out" that works for every situation. Its a measurement you have to creep up on, after several iterations of moveement at the spindle + camber adjustment at the top.

    [​IMG]

    With the splined bolts used on the later S197 and all S550s, its even more difficult to sneak up on this happy medium. If you push the slotted joint all inboard, you get crazy camber but the tire likely rams into the strut. If you go all the way out with this slot, you will have loads of inboard wheel room but still push the wheel outside the fender, even with max camber and cut towers. It takes a little bit of both...

    [​IMG]

    If you have read our S197 Development Thread you might remember that we tried this 18x10.5" Enkei ET38 wheel back in 2010, along with half a dozen other wheels I bought to try to find the magic "off the shelf" wheel that fit this chassis. There was no 18x10" wheel that fit, and the 18x10.5" wheel above only fit the front...

    [​IMG]

    On the back it pokes like mad. And that 10.5" width is honestly just too narrow for the massive width of the 315/30/18 Hoosier. We did our test fitting with a 285/30/18 and a 285/40/18 - the former was too short and the latter a bit tall for the S197. I'm beginning to wonder if 11" wheels are enough for the 315/30/18 tire, and like I said, we had better results with this tire on a 12" wide wheel.

    [​IMG]

    If you can make out those published specs, the 315/30/18 has 12.5" of section width and 11.8" of tread width. They recommend an 11-12" wheel. Again, really should rethink that 10.5" Enkei. And the ability to easily rotate kinda goes out the window with anything wider than a 10" wheel on the S197, due to very differing flange-to-flange axle widths. Unless you are willing to use massive spacers on the Group Buy wheels.

    [​IMG]

    Wheels cost money, for sure, but a set of 18x12" Forgestars costs less than ONE SET OF TIRES. In 2014 we used 7 sets of A7s for the season, on wheels we bought the year before and also used the year after. And with the high level of aero mods, cutting a fender shouldn't be a huge concern. We know the backspacing that can work on a max effort S197 chassis TT3 car like this with 18x12's, probably like nobody else.

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    And a 335/30/18 costs almost no more than the 315. When you are running a heavy car for a class (S197 vs Corvettes) you need to compensate for the mass with more tire than your competitor. Of course a 335 means cutting fenders, and if you are gonna do that, you might as well invest in an 18x13" rear wheel and run the GOD TIRE: the 345/35/18. That pic above is on the 18x12" wheel and they were squeezed...

    [​IMG]

    I'm having this internal struggle now, with our early TT3 prep on our S550. We have a 2680 pound C5 in our class that has max aero, 335/345 A7s, and with driver is almost exactly 1000 pounds lighter than our car on 315s with no aero. We make 417 whp acg to his 288 whp avg. I need to decide if I want to cut up a car that is 8 months old, ya know? That C5 just won TT3 at Nationals and he is a good friend of mine, and the shop that built it is a friend and customer for engines from HPR (that I am a partner at). So I know too much about this setup, and they built exactly what I would build for TT3 if I didn't want to be testing S550 Mustang bits. ;)

    [​IMG]

    We lost to this car in May at COTA by 10 seconds (with my car on street tires), but caught up half that amount at Nationals (they has also added a lot of goodies and speed in that period). It is a chase - fat against light - and we race them again in 3 weeks at NOLA, another aero track, but don't have time to add #AllTheDownforce to our car.


    To the OP: keep up the good work! I dig the canard setup! We have been looking at doing that for a while to one of my cars. :eek:
     
    Last edited: Oct 10, 2018
  7. ddd4114

    ddd4114 forum member

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    Thanks again for the info!

    I was wondering how you didn't have more difficulty fitting a 335mm up front, but if you were cutting the shock towers to minimize the strut-to-knuckle angle, that makes sense. I've already cut mine to add more caster, hoping that would reduce my static camber needs, but maybe I'll have to hack out more of them. Have you guys reinforced the areas you've cut out in any way? The shock towers see a LOT of load, so I'm a little weary of taking too much material out of them.

    I'll have to look more into the larger wheel setup. I'd really like to add flares with tires that big, but after hours of searching, I couldn't find any bolt-on design that wasn't clearly meant for the stance crowd. Any suggestions? I don't have the fabrication skills to make my own, but maybe some simple sheet-metal deflectors, like the ones I have at the front of my car, will be "good enough" to keep drag from becoming abysmal.

    Regarding the canard setup, I definitely think you need something - canards or otherwise - to deflect air upward in all directions as it leaves the outside edges of the splitter. I think you just don't see it more because a lot of class rules are restrictive with stuff like that (i.e. TT4, AI, etc.). I don't have fancy shock pot data, but I found that I needed a lot more rear wing AoA once I started making changes in this area. A clever diffuser setup would probably work best, but it's really hard to design something that actually works there and isn't a total PITA to make. I looked into RHR's new modular tunnels, but they were just a little too big for me to legally install in my splitter without compromising their effectiveness. My goofy end plate design seems to work, but I found the canards at the top were just slowing the car down. I just removed them and found that corner speed and acceleration was basically the same, but I gained 2mph of top speed, and that was worth an effortless 0.3-0.4 tenths.
     
  8. Norm Peterson

    Norm Peterson corner barstool sitter

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    Thanks. I think.


    But I'm afraid that here you're just going to have to accept that the above assumption of yours does not cover all cases or all people. 11" square is what - half an inch wider up front than the current GT/Perf Pack Level 2? 5th gen 1LE rear wheels/tires at both ends? Hardly any more than factory production. Seriously, even if I didn't track my car I wouldn't be looking at anything narrower than 11's except for whatever tires I'd use during the colder 3 or 4 months of the year.


    You'll hear no claims from me about -2° being enough for competition (particularly where there are tire or other contingencies at stake). Understand that that entire post of mine was intended only as comment relative to the amount of 'poke' vs camber, where numbers were necessary. Not as something for you to ridicule, particularly in light of my keeping my word about a couple of rather specific numbers these past four years or so. Think about it.


    I hope you understand that I do understand all of that. And that I also understand that the needs for TT are a little different from a setup that has consistently seen something closer to 25% HPDE/75% street (and after about 6000 miles total still datalogs beyond 1.1g lateral on the same set of MPSS tires).


    Norm
     
    Last edited: Oct 10, 2018
  9. Vorshlag-Fair

    Vorshlag-Fair Official Site Vendor

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    I'm just glad that there are posts here in the corner carvers section to read and reply to. What is up with the massive decrease in traffic here? It Facebook sucking all the oxygen out of the automotive forums??

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    Well we never cut the towers in my 2011 GT, and were able to get 335s up front without that work (but with massive flares). We were also a little cautious about that, as we have seen cracks, "mushrooming" and other problems in (admittedly weaker) BMW E30, E36 and E46 strut towers.

    [​IMG] [​IMG]

    We have repaired many of these on BMWs over the years, and always stitch weld in a 2nd layer of steel inside the towers (BMW makes these for repairs) after we weld up the cracks, re-shape the towers to be flat again, and then sandwich them with a strut tower brace. On the BMW E46 M3 above, right after we repaired and reinforced his towers he was in a car-to-car incident that RIPPED the RF suspension off, tore the strut in half, yet the tower was undamaged.

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    But the S197 is a completely different animal and is a lot more rigid, uses more steel, and frankly weighs more than the BMWs where we see these problems. We worked on a customer's 2006 GT and swapped out some Steeda suspension (above right) for a more track appropriate AST coilover setup with our camber plates back in 2011. You can see my S197 behind it in early form, still fitted with the useless LS plastic splitter Anyway, he really liked the increase in spring rate and damping, but on his own he did this a few months later...

    [​IMG]

    He cut the towers waaaay out there, by hand, and it didn't look bad. It allowed him to get more caster, as you mentioned, but it also allowed for more camber travel at the higher caster setting. As you can see, the S197 is unique in that it has the double-thick sheet metal in this area. He has had this setup on there for the past 7 years with no issues.

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    Another data point we looked at was the Boss302-S, built by Watson Racing. They cut the towers on all of those cars for more camber travel (NOT caster), as you can see above. They only slotted them for camber, and they raced the hell outta those cars, jumping carbs and trading paint.

    [​IMG] [​IMG]

    So back in 2015 we took the plunge and cut the towers on Jamie Beck's 2013 Mustang GT, which was just going from HPDE to W2W use.

    [​IMG]

    Three years of racing and two significant front end hits later, the towers look fine. So I'm no longer worried about cutting towers on the S197. And we just cut the towers on my 2018 GT as well.

    [​IMG]

    Yea, there weren't many S197 flares out when we went to go make them for my 2011 GT in ~2014. The stuff that is out there then was mostly for the Stance-in-my-pants crowd, and most of the show cars we saw with these flares had hilariously narrow tires, like 275mm on this RTR car above, shown at the 2012 SEMA show - even if it was voted the hottest car at the show. ;) I think RTR is good for the drift crowd but rarely do their products help the actual corner carver folks.

    [​IMG]

    We saw this APR widebody S197 at the 2014 SEMA show, but it didn't have much tire on it (significantly less than our 335 fronts parked next to it). It should hold a decent amount tire, but that was a whole "kit" that needs a nose, rear bumper, side skirts, and all of that. Pretty car showy looking...

    [​IMG]

    Everything we could find back in 2012 was "over the top" race car bodies or for looks only. This car from Germany was a bit much, you know? But since 2012....

    [​IMG]

    I'm hot-linking images now so these pics might not work (that didn't work for an hour and I have since replaced them with pics saved in my gallery). Today I googled "S197 mustang flares" and found a number of options from TruFiber and even Maier Racing.

    [​IMG]

    These TruFiber units look more than adequate - if these had been around when we were trying to stuff 335/345s under the fenders I wold have bought them. These do not require front or rear bumper changes, goofy skirts, etc. $550 per axle, and at that price I would have jumped at them back when we did my car.

    [​IMG]

    Maier Racing's flares look good but are only made for the 2005-09 body - they don't cover the 2010-14 bodystyle yet.

    [​IMG]

    We might try to emulate something similar to what the GT4 S550s are running, above. But what you have is a lot more aggressive, and probably more appropriate to what we need for TT3 competition.

    Good stuff!
     
    Last edited: Oct 15, 2018 at 5:30 PM
  10. Racer47

    Racer47 Doesn't have much to say S197 Team Member

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    Is this fixture on your website? I couldn't find it. Whats the cost? What hole size do you recommend?

    Thanks for continuing to post real info here.
     
  11. Vorshlag-Fair

    Vorshlag-Fair Official Site Vendor

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    [​IMG]

    Thanks for the reminder! We made a change last week to add a centering post, to help guide the hole saw. Those arrived Friday and I just went and welded them to the two designs - I will add these on the website tomorrow - $50 each.
     
  12. ddd4114

    ddd4114 forum member

    Age:
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    Once again, thanks a lot for the info! That makes me feel a little easier about cutting the shock towers more, but I might still get a strut bar for peace of mind. I'll take a look into the TruFiber flares, but I think they should work too. I'll probably modify them a bit to help with air extraction, but they look like a good starting point.

    I also wish there was more activity in this section. I know Facebook is quickly replacing forums like these, but I think this is a much better medium to share real tech. I remember 10+ years ago when it was common to see dozens of new threads every day on the Honda forums I followed. That being said... I don't mind having less activity as long as the signal-to-noise is better, but it sure has been pretty dead here in the last year or so. We need to bring it back!
     
  13. Norm Peterson

    Norm Peterson corner barstool sitter

    Age:
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    The S197 is no longer the latest Mustang platform.

    The same thing is happening to traffic on Camaro5 now that the 6th gen has been out since MY2016.

    FB is part of the reason, just not all of it.


    Norm
     
  14. ddd4114

    ddd4114 forum member

    Age:
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    Honestly, I'm surprised that isn't more of a reason for people to look into S197 tech. They're a lot more affordable now that the S550 has been our for a while, and I would assume people are now more willing to mess around with them because it's less of a financial risk. Oh well.
     
  15. Vorshlag-Fair

    Vorshlag-Fair Official Site Vendor

    1,271
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    Norm is right about the S550 pulling away some of the Mustang enthusiasts, but ddd is also right that this makes the S197 more attractive to racers and track rats. We're seeing a TON of S197 racers taking their builds down more serious paths, and we still sell a LOT of suspension parts, brake upgrades, big wheels and more to this segment.

    [​IMG]

    I like the S550 a lot, and it is similar in many ways to the 2011-14 GT/Boss302 cars: similar powerplant, same transmission, fits the same and tire wheel widths (11" / 315mm), similar driving position/visibility, and weighs almost exactly the same. the 5th gen to 6th gen Camaros are more different than the S197/S550.

    [​IMG] [​IMG]

    But there are some key improvements on the S550 that are hard to ignore. The double ball joint front control arm (above right) gives some advantages over the S550 front suspension. And the Independent Rear Suspension is a big step up over the stick axle. And of course these being new/newer cars it is easier to buy one of these using financing over a 4-7 year old Coyote S197... for the casual HPDE crowd, the S550 GT and GT350 sure seem more popular.

    [​IMG]

    Now I've only done 7 track weekends in the S550, and we have only just fixed some of the more serious OEM issues, so I'm still getting a feel for it. But from my early testing the S550 is 2 to 3 seconds faster at the same tracks in the same basic level of modifications than the S197. Again, we haven't run all of the same tracks that are on our schedule in Texas and we are still fixing the basics on this chassis. It might be more.

    One last thing: the name of this forum isn't helping the S550 community find it. Sure, there's an S550 section, which we asked for early on. But calling it S197forums might not "bring in the new kids" that are over at other more generic Mustang themed forums. Might not be the case, just my thoughts...

    [​IMG]

    In any case - keep bringing up questions and adding tech content. It breeds more users!