backbone

[Jack B]

Originally Posted by AdamVIP Im not sure if this has been said in the last 5 pages but this is what I put on kp forum. Please correct me if Im wrong. "The only time where the brace will be noticable will be when the frame is subjected to a vertical force that is not equal across the car. This is nicely showcased with the DDM jack test. Essentially they are putting a vertical point load on one side of the car. It creates a moment which a thicker plate will handle better. In most driving conditions you will not encounter this scenario. In 99.9% of driving cases the forces exerted on this piece are going parallel with the brace plane. On paper the thicker plate will handle this force better as well but youll be spinning well before you you max out the stock piece and notice a significant difference in feel. All that being said I bought a brace from DDM and haveit installed. On the .1% chance I get a road irregularity that wil cause the torsion effect Ill be ready."

How about a little disagreement. The moment of inertia of the plate is insignificant in the vertical axis, but, it is far greater in the plane that opposes longitudinal forces between the two sides of the car. You can view the car as two symmetrical pieces with a box tying them together. When you make the box higher and/or wider you have increased the moment of inertia or strengthened the box structure. This is what the plate is doing, it is the bottom of the box.

Since the box itself is more rigid, the two halves of the car will have less relative movement. The reason the vertical jack test shows less movement is that the jack's vertical force is putting the the plate into tension (horizontal force) and the heavier plate resists those forces better than the oem plate. These are the same forces that you would get from any action that loads one side of the body more than the opposite side.

[nighttripper]

I don't know about the car being quieter, as my magna flow was pretty loud, before installed a resonator from Solo, But one thing I'm sure of, is the car definitely feels quicker in loading the power to the rear wheels. Less squat quicker go.

[King-Oka]

Originally Posted by nighttripper I don't know about the car being quieter, as my magna flow was pretty loud, before installed a resonator from Solo, But one thing I'm sure of, is the car definitely feels quicker in loading the power to the rear wheels. Less squat quicker go.

When I mentioned "road noise", I wasn't necessarily talking about the audible stuff. More like what you feel. - Ever ride a bike with no rubber on the rims? You feel every little road defect. Put big tires on and it goes away. This is like a little more rubber on the rims.

[nighttripper]

Originally Posted by King-Oka When I mentioned "road noise", I wasn't necessarily talking about the audible stuff. More like what you feel. - Ever ride a bike with no rubber on the rims? You feel every little road defect. Put big tires on and it goes away. This is like a little more rubber on the rims.

Got it

[GXP Fetish]

I chose the Race version due to the fact I travel a gravel road approximately one mile from my home to the highway.That's two miles of this road every trip. I LOVE the difference when I drive over a RR Track or a rough spot in the highway.

A definate MUST Have Mod if ya LOVE your Solstice !!!!!

[Speedhawg]

I recently got an email that a very successful race team, who campaign a Sky in Formula Drift have there own version of the "backbone" and have tested it both on the computer sim and in the real world, they will most likely offer one for sale in the future, they absolutely believe it works. By the way the car they have tested it on has over 700 hp from a large V-8.

[Dave@ddmworks]

Originally Posted by Speedhawg I recently got an email that a very successful race team, who campaign a Sky in Formula Drift have there own version of the "backbone" and have tested it both on the computer sim and in the real world, they will most likely offer one for sale in the future, they absolutely believe it works. By the way the car they have tested it on has over 700 hp from a large V-8.

Yeah, we use the same software and the new Extreme version of the backbone is about the strongest thing we have tested (although there are things like the 91# 1/2" solid tungsten backbone that are stiffer, but does have a little bit of a weight penalty )

There is also some other testing that is going on this week that we will post up later in the week

[GXPinKC]

Dave and all the good people from DDMWorks, I just want to thank you for the great work you did installing our Powder coated 3/8ths Race Backbone and Pro Beam at the Nashville Meet. All I can tell you is, that on the way back to Kansas City, I could definately tell a difference on the stability of our GXP and the solid feel it provided in turns, as well as the performance and feel going over railroad tracks (much quieter), all in all, the feel of the vehicle is just perfect now. I thought it was great beore install, now I am a firm believer that the vehicle should not be driven without these additions from DDMWorks. Thank you for your wonderful work in installation. I will wear my black DDMWorks hat with pride. Thanks for the great install and product. I look forward to your next product for the Kappa Roadsters.
GXPinKC
Ron

[Silver_Ghost]

Originally Posted by carbontech i just opted for the street version, i don't think anyone will see the difference between the street and race version unless you are on the track taking extremely hard turns, for anyone who doesn't use their car at the track just grab the street version and call it a day

This may be true. But if your car is lowered and looks slammed like mt car is, then go for the race version. It will help give more structural support and for better peace of mind if your car is sitting very low on Eibach or some type of coil over springs. I don't race my car. But do go to allot of car shows. Everyday streets with pot holes and bumps can take a beating on a lowered car. That's why I say get more support if needed.

[Flash's Owner]

I will try and post a copy of this on both forums.

I got a chance to spend some time with Dave from DDMWorks today. Turns out he was in town, and this provided a rare opportunity to compare Flash's stock chassis to the effects of adding the Extreme version of the Backbone.

Dave was willing to ride along for a baseline run, then the install the backbone and ride along for the evaluation.

Roads included broken concrete at 25 MPH, moderate gravel road washboarding, some ripples and mild twists, a section of 45 MPH sweeping corners, a section that evaluates mild lane changes at 50 MPH, and a near-limit 45 MPH circle. All evaluations were done top down (least structure).

I must say I was initially skeptical regarding the effects of the backbone, which seem to range from nearly nothing to miraculous tranformation of the car. LOL

I can say with reasonable certainty that there is an effect of the addition of the backbone. Some of the effects are surprising, some expected. I would rate it in importance as second behind stiffening the rear crossmember, either through structural augmentation (such as the ProBeam) or use of the Z0K rear crossmember.

In the end, I ended up keeping the backbone on Flash, and paying Dave for the part.


These are the initial impressions from my evaluation, I plan on continuing to "soak" for the forseeable future, as well as have some of my friends/coworkers evaluate my car and get their impression. People who work(ed) on the platform will be interested as well, I am sure.


Steering: There is no significant change to on-center steering feel or precision. Deadband remains as stock, and turn in response from on-center is essentially stock. This is not surprising, as stiffening the rear crossmember is the big ticket item to improving this.

Structural Feel: on small broken concrete inputs and also on the the mild gravel washboard, there a very small, just-barely noticeable improvement in header shake and structural feel. Larger bumps give a slightly higher impression of improved "solidity" to the car. I would rate these in the range of "if you know it is there you will feel it otherwise not". It is not nearly as much as a roll cage might add to a car, for example/comparison.

Transional Handling: Overall roll gradient remains the same. This is not surprising. The transion from on-center to the non-linear range is more linear than stock. I would rate this as about 65% of the effectiveness of adding a Z0K Rear Crossmember. I have never driven a car with the ProBeam, but judging from the size and application, I would expect that this effect is probably on par with the ProBeam. I do not know if the effects will be additive, but I do expect that they will be complimentary additions. While steering effort remains unchanged, the car seems to be a bit slower and more predictable as it transitions into the non-linear range, with an improvement in the steering sensitivity as you move the car toward the limits of adhesion.

Transient lane changes also seem to have some benefit from this overall change. There seems to be less overshoot and the car does seem to have a better directional sense in the transion from linear region (generally around 0.5g) to the non-linear region (up to tire noise, squeal and squall). The linear region, while already quite high, may be slightly higher as well, but I would have to soak some more to determine if this is the case.

Limit of Adhesion: surprisingly, the car picked up noticeable terminal understeer. Stock configuration is reasonably neutral if corner entry is smooth and power application is light to neutral approaching apex, light throttle application and smooth corner exit - results in mild tire squeal from the front and rear at similar levels. Same inputs, same power, same corner, the front tires definitely make more noise, and this is also noticeable on transient lane changes. This is consistent with a change to the roll couple distribution (I call TLLTD or Tire Lateral Load Transfer Distribution).


Thinking back, it is possible that what is really going on is the change to the linear region (possibly an extension), and a more gentle shape to the understeer curve means the car has overall more predictability.

I look forward to getting the chance to install the Z0K rear crossmember and see how the improvements to steering precision play with these changes.


A very huge thanks to Dave for taking time out from his vacation and away from one of the Great Lakes to listen to me flap my gums and provide me with the opportunity to evaluate his backbone.

[GXPinKC]

Thanks Flash's Owner for following through with your promise to evaluate the DDMWorks Extreme Backbone installed on Flash by Dave at DDMWorks. As you know from a post I made on another forum, I had Dave install the Race Backbone and the Probeam at the National's in Denver. I definitely agree with your remarks and I believe that with the addition of both the 3/8th Race Backbone and the Probeam that out Kappa is not only more predictable but also I notice around curves she feels more planted and secure. Anyway, my Race Backbone weigh's 9.5 lbs and the Probeam 9.0 lbs. I believe the stock backbone weighed 5 lbs. So, not being an engineer, all I can say is, that I notice that "Miss Red Eagle" plants more solidly now then before, and I can take corners with more confidence. She takes bumps and railroad tracks better and overall driveability is improved. What is not to like! Anyway, I and Carol are happy customers and endorse these additions by Dave at DDMWorks.

[lil goat]

Thanks for taking th time to hang with Dr. Love (Dave) and see we aren't all crazy and that we didn't drink the Kool-Aid, want to really feel the Backbone work, throw a Z0K sway bar on, they really complement each other. I have the Backbone the Pro Beam and the Z0K bar, plus the HKS coilovers, it is a very different car, stays really flat. I am still tuning the coilovers but it I chased a Porsche 911 turbo through the twisties and he couldn't get away, something is working.

[Treeman]

Thanks Flash's Owner for doing a flat out comparo. I was talking to folks at the Md No Mod Meet today and they sold me on it being "more than a feeling". It is nice to see all arrows pointing the same direction.

Now I just gotta get one!

[bigblau]

Thanks Flash for the review. The backbone feels nice and is worth having, but the Pro-Beam is where I noticed the most handling improvement. I strongly recommend the Pro-beam for those who only have the backbone.

[the4x4pig]

First I want to say I have no evidence as to the effectiveness of the street or race versions. I did buy the race version but have yet to install it.

I read through most of this entire discussion and am not sure if this was said or not. With almost any performance automotive application the same thing holds true (baring a few limited situations). An ideal chassis has zero deflection or movement....zero. That is the job of the suspension. Handling should be tuned in the suspension only. With that said, anything that stiffens the chassis is going to be a benefit to handling. In my opinion there is no reason to go "less stiff". If the thicker backbone does in fact allow less flex than it is the more appropriate product. In an ideal world our cars would not flex at all anywhere. This notion that you need stiffer or less stiff depending on the HP, Tq, or driving habits just does not work. Some might not notice a difference between the two but more flex IS NOT BETTER for any application of our cars. The only good reason I have heard to justify buying the street version is if you can not justify the price of the race. If the chassis is flexing at all it negatively effects the geometry of the suspension components.