Cortex Torque Arm Racechrono Track Review

[2013DIBGT]

Roush's anti-wheel hop kit is in a unique position. The bushing durometer is inbetween OEM and poly yet has a lower hole on the mount to increase AS. You would have to put a spherical on the diff side to reduce bind as it obviously doesn't articulate, but you would wind up with increase AS and certainly a lot less NVH than a poly. I would be assuming that bind wouldn't be introduced until the spherical at the diff reached max travel and started binding. How far that in travel until that happens, I have no idea.

Yeah, I was eyeballing the Roush UCA kit myself during the initial planning phases of my suspension build and considered using it in combination with the Maximum Motorsports Extreme LCA's which use Sphericals at both ends. I read of a few other folks running that setup with success and had minimal NVH increase.

Ultimately I choose to not go that route because I feel the TA setup appears to be a far more durable option when used with whatever flavor of LCA / Relo bracket that is chosen. I guess I'll know soon enough if my gut feeling was right or wrong.

In my case, I'm sold on the whole Cortex rear end package because it is just that, a package designed to work together using components tested with each other to provide a complete solution.

I've done the piece meal setups in the past and while they certainly worked they were almost always more difficult to install due to parts not always lining up just right at which point I would find myself saying "I should have gotten that damn package from brand X instead" while I'm seeing Red hammering the shit out of a bolt that should just go right in.

 

[barbaro]

This is a quote from Cloud9 on the Bossmustangonline forum. He has a Boss 302 and a GT500 to which he has attached a Griggs Gr40 ss (super street) Rear end package of Torque Arm /Watts Link/lca (rod end). Read his comparisons of the two:
Quote from: cloud9 on April 29, 2012, 09:19:37 AM
I was driving my GT500 last night and while it's very nose heavy and likes to push through turns, I can't believe how it squats and just goes when powering out of corners. It's WAY better than the Boss where I have to tip toe around corners on city streets or I'll break traction and get the axle tottering with wheel hop. I don't notice that as much at the track, but of course the corners aren't near as sharp. The GT500 has rod end control arms and the 3rd link is a torque are, but I also have a Watts. I'm hoping that the rod end FRPP LCAs, and spherical bearing Steeda 3rd link, along with lower stiffer springs will take care of this on the Boss.

here is more: Commenting on the differences between his Boss and GT500:

Quote from: cloud9 on August 18, 2013, 08:14:34 AM
Nice! I will be anxious to hear about your results as you test different setups. I am looking for more forward bite out of the rear when accelerating through corners. Any suggestions on suspension adjustments? I really feel like I am having to wait too long to get back to WOT compared to my GT500. It does have a torque arm though and am wondering if that's the main difference.

 

[barbaro]

Here is another quote where he indicates he does hear more gear whine. I should point out that the Cortex torque arm uses a different design and bushing for it's Chassis attachment:

I would say that I have noticed some increased gear whine and I suspect it's transmitting through the torque arm. This is all going to depend on the person and what you consider too much noise. It also presumably depends on your level of gear whine. I have 3.73 gears and they have whined since a few months after they were installed (two years prior to the torque arm). I can't say if you're running stock gears whether you'd notice any gear whine, or if you were one of the lucky few that have 3.73 gears that don't whine. Wow that's a lot of whining! :hysterical:

I think the bottom line on NVH is this. If you want a quiet GT500, don't mess with your gears, suspension, exhaust or even blower. The reason our cars come with "crappy" suspension from the factory is that they engineered virtually all of the NVH out of the car. To do that they used a lot of rubber bushings and "soft" suspension components. The tradeoff for that is a 4,000 lb car that hops like a bunny and pushes through corners.

I usually have both windows open and have my stereo turned up so loud I don't hear any NVH from the car. Now if I could just do without that Shaker 1000 I could really lighten this baby up!
2007 Shelby GT500
Vista Blue with White Stripes
640 rwhp/625 rwtq
Mods:
VMP Custom Tune, TVS 2.3L supercharger with Stiegemeier interchangeable hub and 2.6" & 2.9" Metco pulleys, FRPP CAI, Griggs GR40SS with Watts Link and front Koni coilovers, Revan Racing twin fan heat exchanger, Revan Racing radiator, VMP Intercooler Reservior Tank, 2008 GT500 lower pulley, Goodridge Steel Brake Lines, DBA 5000 2-piece Slotted Rotors, Hawk DTC 60/70 Pads, JLT Brake Cooling Kit, FRPP SVT1 Exhaust, FRPP 3.73 Gears, CHE Drive Shaft Safety Loop, Aeroforce Interceptor Gauge, Homelink Rear View Mirror

2012 Boss 302 CO/BK with Recaros/Torsen - Aeroforce Gauge, LS wing, Corsa Extremes, Trans scoop, brake cooling hoses, SS Lines, MM c/c plates, JLT Oil Separator, MM 4pt roll bar, 302S (suspension,hood, grille, splitter radiator, air-to-oil cooler & tow hooks), MGW Shifter, ARP studs

 

[55R2014]

But the problem is that by replacing the diff side bushing with a spherical bushing, you'd be eliminating the full amount of that bushing's anti-NVH effect. Now, suddenly, you're asking the chassis side bushing to absorb the full amount of NVH, not just whatever amount was previously being absorbed there. And that bushing has already been reduced in its ability to absorb NVH due to the change in material.

I'd thus expect to see a massive increase in NVH (relative to stock) through the use of that kit. Of course, the only way to really know would be to try it...

I had a conversation with Filip from CorteX toady. We discussed the NVH issue. Since my car has his full suspension on it. We will temporarily replace his lower control arms with the stock factory lower control arms that came with my track pack suspension to see if the NVH gear whine is reduced. We will test some other options he has available to see if can find a way to reduce the NVH.

My car has 3.73 gears. I got the gear whine noise after installing the full suspension with watts link before adding the torque arm. The torque arm add no additional noticeable NVH to my car. I will try to get some measuring equipment if possible.

 

[2013DIBGT]

I had a conversation with Filip from CorteX toady. We discussed the NVH issue. Since my car has his full suspension on it. We will temporarily replace his lower control arms with the stock factory lower control arms that came with my track pack suspension to see if the NVH gear whine is reduced. We will test some other options he has available to see if can find a way to reduce the NVH.

My car has 3.73 gears. I got the gear whine noise after installing the full suspension with watts link before adding the torque arm. The torque arm add no additional noticeable NVH to my car. I will try to get some measuring equipment if possible.

Interesting. In your case I guess the LCA would be the only possible culprit assuming Pinion Angle was set to exactly what it was originally and that the LCA's length are set to the exact same length as the OEM LCA units.

I forget, but do you have the Poly/Spherical Cortex Arms now?

On a scale from 1-10 where would you rate the gear noise you are hearing as compared to stock?

Is it safe to assume that the OEM LCA's will work with the Cortex Relo brackets in place or would you need to remove them as well?

I wonder if a healthy dose of Dynamat or similar applied in the general vicinity where the LCA's attach to the body of the car would reduce the resonance?

 

[55R2014]

Interesting. In your case I guess the LCA would be the only possible culprit assuming Pinion Angle was set to exactly what it was originally and that the LCA's length are set to the exact same length as the OEM LCA units.

I was also thinking that the mechanical connection between the watts link on the diff cover would add to the gear whine as eel but maybe not. On the watts link rods, I have poly on the farm ends and rod ends on the pivot connection.

I forget, but do you have the Poly/Spherical Cortex Arms now?

I do have the poly on the frame end of the of the lower control arms and rod ends on the axle end.

On a scale from 1-10 where would you rate the gear noise you are hearing as compared to stock?

On a scale from 1-10…1 being stock(quite) and 10 being loud(I don't care, its a race car), to me, mine is a 3-1/2. That's about as scientific as I can get at this point. The pitch of the whine goes higher as speed increases, and goes lower as speed decreases.

Is it safe to assume that the OEM LCA's will work with the Cortex Relo brackets in place or would you need to remove them as well?

I'm not 100% sure but I would imagine they would. It may require type of spacer proper alignment. I will take pictures and record what changes have to be made for this test.

I wonder if a healthy dose of Dynamat or similar applied in the general vicinity where the LCA's attach to the body of the car would reduce the resonance?

I would imagine dynamite in the right places would help decrease the resonance and noise. At this point, my car has no Dynamat. I exhaust system is Borla x-pipe, mid-pipe, and "quite" touring mufflers. I might slip the stock mufflers on if it needed but don't think it will be necessary.

 

[Whiskey11]

Alright folks, finally got some photos taken for Filip on the install and I figured I would share them here. Keep in mind this is a "prototype" part so some things were done a bit "ghetto" to get things dialed in more. Filip was consulted before anything was changed and none of this will or should be a problem in later models if he decides to offer this setup for the finned differential cover:

The Torque Arm itself. Nothing "unusual" here. You'll note that the driver side exhaust hanger had to be rotated 90º. To get the tips to line up I had to dremel off the stud the exhaust clamps over.

Fays2 Watts link clearance to the diff cover... not a lot. Some stiffer control arm bushings would make this setup less likely to rub. I don't think it does now but it certainly wouldn't be impossible if you hit a bump hard enough to displace the rear axle rearward enough.

This is one of the areas that will be changing on future production parts. I called Filip while under the car to discuss how to get the two bolts you have to put through the ears on the front of the differential to be far enough in to safely bolt through the ears. He suggested washers as a temporary fix until they can get a modified mount done. I also had to replace the hardware for the lower 5 bolt holes to 2" long full thread bolts. The factory bolts are 2" long but only 1 7/8" worth of thread. In total, the 4 washers come out to about 5mm or a 1/4" worth of spacer.

Finally, a glamour shot. I should note that the actual arm itself is powder coated, the bracket for the diff cover was spray painted to expedite me getting the parts before the Midwest Divisional Championship. Finalized parts will be powder coated.

Let me know if you have any questions about the mounting. I'll try my best to answer.

 

[Whiskey11]

I figured I should go ahead and update. The clunking, the gear whine and all that started to get the best of me. I have probably close to 40 autocross runs on the Cortex Torque arm as it was installed so I decided to nut and bolt the entire Torque Arm... AGAIN. All the bolts were tight so I opted to do the leg work to go ahead and rebuild the whole front mount so I loosened all the bolts took the cross member off and rebuilt the whole thing.

Good news is that the noise has toned down, a lot. I wont say it has eliminated the clunks entirely because I wont know until I drive it for a few days but it appears that whatever I did toned down the driveshaft noise (clunks on shifts) substantially and gear noise has toned down some too. The rear end feels freer now so I have no idea if I just installed it wrong (probably ) the first time or what but I feel better about the purchase now.

I haven't heard back from Filip yet about the photos and notes I sent him as I think he is finishing up the NASA finals at Miller Motorsport Park. I think I'll shoot him another email just to touch base again!

 

[55R2014]

I figured I should go ahead and update. The clunking, the gear whine and all that started to get the best of me. I have probably close to 40 autocross runs on the Cortex Torque arm as it was installed so I decided to nut and bolt the entire Torque Arm... AGAIN. All the bolts were tight so I opted to do the leg work to go ahead and rebuild the whole front mount so I loosened all the bolts took the cross member off and rebuilt the whole thing.

Good news is that the noise has toned down, a lot. I wont say it has eliminated the clunks entirely because I wont know until I drive it for a few days but it appears that whatever I did toned down the driveshaft noise (clunks on shifts) substantially and gear noise has toned down some too. The rear end feels freer now so I have no idea if I just installed it wrong (probably ) the first time or what but I feel better about the purchase now.

I haven't heard back from Filip yet about the photos and notes I sent him as I think he is finishing up the NASA finals at Miller Motorsport Park. I think I'll shoot him another email just to touch base again!

Glad to know there was a reduction in the noise. I wish my clunking noise would be easy fix. Mine is somewhere I the driveline. It was there when I bought the car.

Filip told me he was going to Miller so I hope to catch him this week as well.

 

[Whiskey11]

Glad to know there was a reduction in the noise. I wish my clunking noise would be easy fix. Mine is somewhere I the driveline. It was there when I bought the car.

Filip told me he was going to Miller so I hope to catch him this week as well.

My guess is that it's the driveshaft, because, well, the 2 piece driveshafts on these cars SUCK. If it's not that then it's probably the backlash in the differential. If I ever get the Torsen T2R in this car I think I'm going to buy all the components to "do it new" and put a new gearset in and have it setup with slightly tighter backlash.

Hopefully everything went well out there for Filip, I just saw Maximum Motorsports had a few of their guys on several podium spots so I wonder how Cortex Racing did?

 

[2013DIBGT]

Thanks for the update.

Wanted to get some opinions on something I have been considering doing when I install the Cortex kit on my own vehicle.

Seeing that these kits use Rod ends which are known to loosen after some period of time I wonder if there is enough thread and clearance available on the bars to allow for the addition of another nut (thinner, but same thread pattern) which would act as a locking device to the already provided nuts on the Rod Ends. The thought being that this extra nut may help prevent the backing out of the already provided nuts and maybe prolong the time they would stay tight and not come loose.

Sorry for butchering your Pic Whiskey but it seemed like a good example to use to show what I am talking about. Red ring location would be where I am thinking these nuts could go on all similar bars with the Rod Ends on them.

Thoughts? Thanks

 

[Whiskey11]

Thanks for the update.

Wanted to get some opinions on something I have been considering doing when I install the Cortex kit on my own vehicle.

Seeing that these kits use Rod ends which are known to loosen after some period of time I wonder if there is enough thread and clearance available on the bars to allow for the addition of another nut (thinner, but same thread pattern) which would act as a locking device to the already provided nuts on the Rod Ends. The thought being that this extra nut may help prevent the backing out of the already provided nuts and maybe prolong the time they would stay tight and not come loose.

Sorry for butchering your Pic Whiskey but it seemed like a good example to use to show what I am talking about. Red ring location would be where I am thinking these nuts could go on all similar bars with the Rod Ends on them.

Thoughts? Thanks

That picture is of course a picture of the Fays 2 Watts link as there are no rod ends on the Cortex Torque Arm. To answer your question, that is not the part that loosens up to cause noise. It's the actual ball portion of the rod end that causes the issue. The teflon liner wears out and they develope a slight movement, just enough to cause added noise vibration and harshness.

I can't say I've ever had that part cause added noise because it loosened up but I have replaced the rod ends because they were squeaking.

 

[55R2014]

No noise from my torque arm. I have not replaced the rod ends on the watts link either. Since I am running the street version my lower control arms have the urethane bushing on the front of the lower control arms where it connects on the frame end. I had rod ends on the opposite end on the axle. The originals I put on started to rattle after some time so I replaced them with Johnny Joint ends that CorteX has customer made for their application. Those rod ends are perfect and quiet. I put them on about 20,000 miles ago and they are still quiet. I have over 45,000 street miles on my CorteX suspension. I couldn't be happier!