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S4S chassis braces

2932 Views 4 Replies 2 Participants Last post by  jbmnsx
SPEED for SALE Chassis Braces

Last year I started taking my car to the track for road racing events and was immediately hooked. Since then I have been modifying my car specifically for road racing. In the spring Speed for Sale (S4S) started selling a front shock tower brace designed by KM Motorsports.

I was very pleased with the bar so when S4S announced they would be selling a set of chassis braces designed by the same company I thought I would give them a try. Jeremy Blackwell at S4S provided me with a set to test out and to write installation instructions from the stand point of the DIY owner. In addition he wanted my impressions of the braces from the point of view of an amateur (and not that experienced) driver. Although Jeremy did provide me with a discount on the braces I am not being paid for posting. I also made it clear to Jeremy that I would be giving my honest opinion one way or the other.

I know that there was a previous post on these braces and some discussion of knock off versions. I didn't read the thread that closely so as not to be influenced by it. Jeremy has assured me that the set I have is the real deal. Not that I have a problem with some knock off parts but when it comes to suspension and brake components I like to know where they came from.

The braces are relatively easy to install and can be done by any owner experienced in working on their own car. I have provided Jeremy with detailed instructions which he is currently reviewing and will post on the S4S website

Now for the braces themselves. If you look under the car the goal for the center brace is pretty obvious. The center brace is designed to bridge the gap left by the tunnel that runs down the center of the car. As supplied by Nissan the GT-R has nothing holding the two sides together such as a transmission mount cross member. The S4S center brace crosses this gap in two locations and mounts to the unibody rails in the front and to a tunnel brace in the rear. Although it is difficult to tell the difference the car does feel tighter on the extremely bumpy section of my street test track. I think that the center race would be helpful on tracks with significant elevation changes like the bach straight at VIR. After cresting the hill you drop down and quickly come up again. This is a hard braking area and puts quite a strain on the car. The center brace will prevent the car from flexing down the centerline which would have an impact on the suspension geomtery. As an added benefit the brace should prevent the drive shafts from dropping down should they fail.

At first glance it is hard to tell what effect the front and rear braces will have on the car. They mount where the front and rear sub frames are. The OEM frame members are made out of heavy duty stamped steel and the braces are made of aluminum. However, on closer inspection the braces mount to bolts that attach control arms (these bolts are also used in the car's alignment). Looking at the car and the parts break down these bolts appear to go through rubber bushings where control arms pivot.

This is where I go out on a limb with a saw in my hand. On some of my previous cars and customer cars I have replaced the OEM rubber bushings with harder urethane bushings. The result was a tighter steering feel because the new bushings did not allow the suspension components to move around under load. It is my humble opinion that these braces not only add some additional strength but also prevent deflection of the suspension components under load as they are now linked together. This in theory prevents any change in the alignment.

Driving the car. Whenever you make a modification like this it takes a skilled driver on a track to really tell if there is an improvement. I am not a skilled driver and have not had a chance to get the car on the track. Often the mind plays tricks on us and because I spent time and money on these braces my mind tells me they have to make a difference. However, I honestly believe that there is a tighter feeling to the steering and handling. I have been pounding the car for thelast couple of weeks on all the types of corners and track surfaces you will encounter on the track. And I must say that the car feels more surefooted in turns and much tighter, with less wandering. This is most evident at speeds in excess of 150mph.

My next step is to get the car to the track and see how it reponds. I hope also to be able to do some with and without testing. I will post my final findings then.

Are these braces worth the money? It's hard to say. I think the experienced driver looking to find a few seconds (or 100th) on the track will find more value to these these braces. As for me I feel it was worth it and as my driving improves I will see more benefit from them.

As far as I know, to make sure you get the real deal you need to get them from Speed for Sale. Jeremy Blackwell deals directly with the manufacturer and has been very generous with his time to get me answers to mu questions.

Here is the link to the S4S website;

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Sorry, I know it was long but I wanted to give the pros and cons as best I could.


Just curious, what year GT-R do you own.

Just wanted to update this thread. I finally got to the track with the braces on the car and it seems to me that the steering feels tighter than before and the car did not want to push as it has done on me before. I can't say that there was a dramatic difference in the car. This is just MHO and you will need to do your own cost benefit analysis.

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