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Discussion Starter #1
At what point does it become useful to install a front shock tower strut brace? Can this point be expressed in sustained G-force numbers? Or, more simply, when moving from a summer high performance tire such as the MPS4S to a Cup2 or RE-71r?
 

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It is a preventative tool. It will help the front stiffness. How much is relative to your track driving style and cannot be quantified. With a few GT car towers having failed, it will provide extra protection/reinforcement just in case.

I hit a pothole in front of a curb at mid-ohio and dented a rim and the jolt was severe enough that I pulled into the paddock and inspected the tire and tower. Dent was mild enough to continue the weekend, the rim was repairable, but the rack was internally damaged (and still needs replacement) and the tower was fine. I attribute the minimal damage to the strut brace.

With 718 rear lower strut brace, the BGB harness bar that ties the rear top struts together. and the Schnell front top strut brace, a PCA instructor told me my Cayman handles like it is on rails. 245/295 Sport Cup 2s, lowered, monoball suspension, and spacers help contributed to that description.

V6
 

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I just ordered a front strut brace for my 07 Cayman. This will minimize the strut towers from moving around, sort of like to balance the Pedro's TechnoBrace in the rear. I know one is on top and the other on the bottom, but if it will allow better turnin, I will be happy. I do not have a top BGB harness bar, but will have a Cantrell MotorSports roll bar that does the same tie together next year. I like front bais with 255/35/18's and 275/35/18 r on wide front 9 in wheels and 10 inch wheels in the rear. This combo give good balance for my low powered car.
 

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Racing Dynamics front strut brace $165.00 plus shipping. Hopefully it fits. They also make a carbon one that looks very sexy, but this will be covered up so who cares. Moving from RE71R's to Hoosier A7's. Changes some things, but they are still tires. I find myself overdriving the Hoosiers. I just need to be a smoother driver. Install took about 1/2 an hour.
 

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I forgot to add that the towers are glued onto the tub and held by a few rivets to ensure the alignment of the parts don't move while the glue cures. For this reason alone, a strut brace should be on all 981 track cars.

V6
 

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Yeah I'm worried about that too, seeing so many 981 front towers fail. Especially now that I have stiffer suspension.

I haven't seen a lot of 981 front strut braces though. What options are out there? And if only bolts onto the top 3 strut bolts, it isn't really strengthening the tower's load capacity, which doesn't really fix the ultimate problem.
 

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Discussion Starter #8 (Edited)
"Moving from RE71R's to Hoosier A7's. Changes some things, but they are still tires. I find myself overdriving the Hoosiers. I just need to be a smoother driver."

This is my thread so I can steal it.

Can you elaborate on why you made the switch and what you are experiencing subjectively (feel) and objectively (G-force)? Be specific about both brand sizes.

Many of us are on this cusp, looking over the edge. I had Hoosier slicks on a memorable Formula Ford I raced for several years. They stuck like a pact with the devil. Then, like, I presume, the END of a pact with the devil, they went over the edge and let go with little warning.

When that happened, if you didn't make the right correction very quickly, you spun. It was fine once you developed a feel for the exact correction at the muscle synapse level. But not so fine until then.

It is always better to have this 'splained to you in a Skip Barber classroom at Road America before the fact than to learn about it at 120 mph in The Kink.

A memory of that Hoosier edge lingers; it beckons. I wonder if it is the same in our cars. Your word choice--"overdriving"---suggests that it is.
 

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Racing Dynamics front strut brace $165.00 plus shipping. Hopefully it fits. They also make a carbon one that looks very sexy, but this will be covered up so who cares. Moving from RE71R's to Hoosier A7's. Changes some things, but they are still tires. I find myself overdriving the Hoosiers. I just need to be a smoother driver. Install took about 1/2 an hour.
Sorry to bud in here but what is the fitment like w.r.t the cover? I got the Schnell one and it is also very polished and works very well but the cover does not sit well and I'm afraid of the occasional water I see pooling around. Thanks in advance.
 

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ajahearn-This brace sits behind the battery, with no fitment interference with the battery cover and side covers and looks almost the same as the Schnell brace, at least on my 987.

dcharnet-I am using A7's not R7's. Big difference in compounds, so not sure this relates to your application. The RE71R's in my application are about 2 seconds slower around the 60 second course than the A7's. Last weekend was my first drive on these tires, leapfrogging a number of drivers in the top time of the day standing. Lets just say, my performance was unexpected and noticed by many including the timekeeper. The overdriving mentioned in the above post was a statement from Hoosier's own A7 direction (tire care and safety guidelines) on how not to abuse the tires. In my case, I found that my brain was not calculating fast enough to keep up to the cars speed, so I was slightly behind in corner entry, making the front tires do more work with increased slip angles, which they did. As I get adjusted to their speed/grip, I will settle down and use smoother driving techniques.

The actual balance was better than I expected, but interestingly the nose of my car kept raising, due to the back shock settings at 8 clicks from stiff vs 3 clicks in the front causing the rear to squat. I don't think I was quite lifting the inside front off the ground, but could have coming out of some of the corners. This corner exit traction was much more noticeable with A7's than with RE71R's. I do not have a G meter in my car, but I would think that the tires were producing much greater G loading as well. My next test will be a smoother track so I can revert to a 5 clicks f and 7 clicks r Ohlin setup. The spring rate is 400 lbs/in f and 458 lbs/in r. The Tarett GT adjustable swaybars were set at 3 out of 5 holes from stiff f and 3 out of 4 holes from stiff r. I have inquired about stiffer spring rates/valving for the Ohlins to match the performance of the Hoosiers and slightly more front camber, all per their chassis setup recommendations. Currently using -2.7f, will increase to -3.0. R's ok at -2.5. I run in a modified GT3 group that includes, GT3's, GT4's, new, older 911's/tturbo's and Cayman's/Boxster's.

Overview of Hoosier A7's vs RE71R's is A7's produce much more grip in every slip angle, braking, acceleration, slip angle less than 10 degrees, mid corner throttle modulation, trail braking etc. All needing drivers style adjustments to prevent "tossing the car" as compared to using relative low slip angles. Looking at the Hoosier A7 tire wear, I will use a little more tire pressure going forward as the outside f shoulders were scrubbed more than the middle of the tire. Hoosier recommends 10% of car's weight with driver and fuel in PSI. So, 34 PSI vs 29 that I was running. Because the side walls of the A7's are much thinner than the RE71R's, running low tire pressures should be avoided. Brake pad effect was ok, no flat spots, although I did threshold brake a number of times due to "over driving" or under thinking, but still faster. Wheel widths are also a consideration as the tread width is the Hoosier recommendation. So a lot of camber and smooth driving habits wins the day with A7's tires.

To compare the oversteer threat that you are worried about, MP4S's, which are my daily drivers are much more prone to oversteer on my car than RE71R's and certainly less with Hoosier A7's in that order. All my tires are the same size; 255/35/18's f and 275/35/18 r.

By the way, Hoosier's ARE DOT approved and stamped on the sidewall of the tire, but carry a Hoosier WARNING in their guidelines, they are Not intended for Highway use.
 

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I can tell you that front strut stiffeners work, as per the noise reduction, shake reduction and down hill steering/braking/traction/stability/control on the front end after adding the Racing Dynamics strut brace. I'm now convinced that as Voyager6 suggests the BGB harness bar maybe in my future if it does tie together the top rear shock mounts of my 987. If not, maybe a roll bar with supports located on the rear shock towers will be the ticket if the bar has a cross link from one tower to the other.. I have followed his lead a few years ago down the slippery slope adding Tarett Cup LCA's to Ohlins coilovers forming a a combo that I love. Stiffening those suspension parts upwards, backwards and forwards, I have found mostly good results from past upgrades that are now necessary when using Hoosier A7 tires. Theses tires bring out the flaws in your suspension including spring rates, valving, camber plates or LCA's, adjustable swaybars, motor mounts, transmission mounts, and driving style.

How do I measure that result, by track timing vs my competitors, which is an evolving and moving target.
 
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