Saturn Sky Forum banner

1 - 20 of 39 Posts

·
Registered
Joined
·
78 Posts
Discussion Starter · #1 ·
What do you think of this thing?


"The KTV replaces the thin original sheet metal of the GT. It is mounted at the existing screw connection points.

This results in a significant stiffening of the cardan tunnel and a noticeable reduction in torsional twisting of the Opel GT, which is particularly noticeable when accelerating out of bends. Engineered and made in Germany:

The reduction in torsion compared to the original version is approximately 10%."

If you place your finger just in the union between the shifter panel and the central front panel you will fell chasis torsion when going over bumps and when driving hard in general. Will this invent really increase chasis stiffness in any noticeable way?
 

·
Registered
Joined
·
1,003 Posts
Here in the States I would say most of our owners- use products from the list of
vendors who provide parts for our model's chassis- as upgrades to the stock set up
from the engineers at the factory. DDM Works has several braces to improve the chassis
depending on how much our owners want, to stiffen it up to their individual tastes for structural stability.
For normal everyday driving the ride will differ between owners. Front end, the transmission tunnel, especially on a Vert- plus the rear end.
Minor improvements to all of these area, can improve things for the owner, however I have read, that some owners have removed braces by personal choice.

Add in suspension stiffness to the equation, more refinement can be made to the personal taste of the owner, their driving style, roads traveled, usage, to customize the OEM set up. If you were running this car as a track day special- I can see the improvement in lap times, with an upgraded chassis over a stock one. For everyday use maybe not as much. I'm sure our owners who have upgraded their chassis will chime in with Pro's and Con's of choices, and money spent with upgrading the chassis stiffness to our model, from the OEM set up.

I have seen the manufacture listed before here- rear struts for the trunk lid- but I don't know enough about their products to judge them per se. Given your location, DDM works products for our model is out of the question, so the German mfg, might be your only option for upgrades to your chassis? Try the tunnel brace see what it does for you? Replace your shocks, bushings, maybe sway bars then see if there is an improvement
to body flex, roll, & rigidity. You should notice an improvement here, depends on your budget for such upgrades.

LAC
 

·
Super Moderator
Joined
·
6,577 Posts
What do you think of this thing?


"The KTV replaces the thin original sheet metal of the GT. It is mounted at the existing screw connection points.

This results in a significant stiffening of the cardan tunnel and a noticeable reduction in torsional twisting of the Opel GT, which is particularly noticeable when accelerating out of bends. Engineered and made in Germany:

The reduction in torsion compared to the original version is approximately 10%."

If you place your finger just in the union between the shifter panel and the central front panel you will fell chasis torsion when going over bumps and when driving hard in general. Will this invent really increase chasis stiffness in any noticeable way?
As @LAC Sky mentioned, DDM has a similar product and they did a demo showing that it does indeed stiffen the chassis to the extent that it is easy to lift a wheel off of the ground when jacking a different corner of the car.

The question is whether an immensely stiff chassis is a good thing for a street car. There is no question in my mind that it is good for a track car, but I found that it made street driving slower in addition to less comfortable.
 
  • Like
Reactions: Gtholic

·
Registered
Joined
·
1,170 Posts
The question is whether an immensely stiff chassis is a good thing for a street car. There is no question in my mind that it is good for a track car, but I found that it made street driving slower in addition to less comfortable.
That is very interesting input.

I had considered the upgrade but didn't want to experiment at such cost. I was hoping someone local to the Chicago area had a used one to sell. I figured if I didn't like the change, then it was no great loss.

But JohnWR, you answered my question already. I was hoping to improve cruising comfort, not reduce it.
 

·
Registered
Joined
·
46 Posts
I would agree with @JohnWR as well, there is a bit of a laws of diminishing returns with an overly stiff chassis for a street driven car. We do not drive on Yas Marina F1 perfect black tarmac. Instead we have road undulations, dips, broken sections and various road imperfections. An overly stiff car tends to skip and skate on these road imperfections.
I think the Kappa would still stand for some chassis brace, but I'd avoid going all out unless you're dedicating the car for track duties.
 

·
Premium Member
Joined
·
210 Posts
This looks like it's at least as good as the DDMWorks backbone brace.

Either the Schwarz or the backbone go a long way to making your kappa more pot-hole proof.
 

·
Premium Member
Joined
·
680 Posts
I installed the DDM brace kit, and barely noticed a difference.
I wonder if I uninstalled it, would I notice any difference?

I didn't start canyoning until I had installed all of the braces.
 

·
Registered
Joined
·
2,628 Posts
I noticed a definite 'unsettled' period under hard cornering when I first drove my car. I added the DDM stiffening measures and it definitely improved that situation without unduly affecting ride harshness.

I later fitted BC Racing shocks and springs which to my mind did further improve handling, although the stiffer springs did have the effect that John mentions, and some would prefer not to have that..
 
  • Like
Reactions: Gtholic

·
Super Moderator
Joined
·
6,577 Posts
I found that the DDM ProBeam made a distinct improvement in handling, especially in transition into and out of turns, with no negative impact on ride quality. I have strongly recommended the ProBeam to everyone.

The tunnel brace or DDM BackBone I found to make the car feel much more stable as would be expected by stiffening the chassis, although it also made the ride harsher. Testing later revealed that I was actually slower with the BackBone than without it, and my suspicion is that the problem was the loss of traction that occurs when the car encounters a single-wheel bump.
 
  • Like
Reactions: Gtholic

·
Registered
Joined
·
78 Posts
Discussion Starter · #10 ·
i understand. There are already too many irregular roads and plenty of speed bumps in my area, So will probably avoid this thing.
 

·
Registered
Joined
·
1,170 Posts
I have yet to remove my OEM backbone. How thick is it? I assume it does something to increase chassis rigidity compared to removing it. I have no plan to drive without the OEM one figuring it serves a purpose in chassis integrity.
 

·
Super Moderator
Joined
·
6,577 Posts
I have yet to remove my OEM backbone. How thick is it? I assume it does something to increase chassis rigidity compared to removing it. I have no plan to drive without the OEM one figuring it serves a purpose in chassis integrity.
I would certainly not remove the OE panel.
 
  • Like
Reactions: Gtholic

·
Registered
Joined
·
1,170 Posts
I would certainly not remove the OE panel.
I was going to remove it only to clean it. I recall looking down from above when replacing the lower gear shift boot thinking it could use a good cleaning in there. I wouldn't dream of driving the car without it mounted.
 

·
Super Moderator
Joined
·
11,510 Posts
I have yet to remove my OEM backbone. How thick is it? I assume it does something to increase chassis rigidity compared to removing it. I have no plan to drive without the OEM one figuring it serves a purpose in chassis integrity.
It is ridiculously thin. It has a 90 degree edge all around it to strengthen it but it is very very thin. I STILL wouldn't remove it as it is there to stiffen the chassis.

Like John mentions, if you have rougher roads, the backbone may not be the best upgrade for you. Chassis flex does smooth the ride and will assist in keeping the tires on the ground in super bumpy conditions. Of course a softer suspension would do the same but there are other sacrifices to that.
 

·
Registered
Joined
·
1,170 Posts
So the extremely thin OEM backbone must accommodate for some amount of flexing that a DDM version eliminates.

Like I said before, my plan was to remove it, clean things up, then reinstall it. I would never drive the car without it in place.

I had hoped to get my hands on a thicker aftermarket version in used fashion to experiment with to see if I liked it. My logic says, thicker-is-better, but apparently "touring comfort" is sacrificed.
 

·
Registered
Joined
·
78 Posts
Discussion Starter · #18 · (Edited)
As i understand it, roadsters usually are less rigid than coupes because there is not roof, so chasis reinforcement must be added, specially in adapted designs that were not roadsters originally. Kappas are roadsters originally, so i suppose the chasis is designed since the beginning to be stiff enough without the need of a roof, but i though some extra stiffness could be a good thing. Obviously there is a limit for reasonable chasis stiffness and some flexibility must be preserved.

Btw, i have seen somewhere a Solstice Coupe. It must be more rigid than a stone.
 

·
Super Moderator
Joined
·
6,577 Posts
........
Btw, i have seen somewhere a Solstice Coupe. It must be more rigid than a stone.
The Solstice "Coupe" isn't really a coupe, and is legally classified as a convertible. The center roof section lifts out completely, like Triumph's Surrey Top or the Porsche Targa Top, and does not contribute to chassis stiffness.
 

·
Premium Member
08 Redline. RPM"s CAI, charge pipes, CAT delete & ECM Tune. diy tunnel brace. ProBeam.
Joined
·
41 Posts
After I replaced my tunnel brace with my DIY version, my wife (who knew almost nothing of what i was doing) asked me if the car is riding better and how i got some of the squeaks out. She knew i was sorking on a project, just not what it really did when i told her about it. Slower, faster? I don't care. I LOVE the way it rides with the tunnel brace replacement. 55k miles and stock suspension at that point.
Since then, all I have done to the car performance-wise is install the Pro Beam. THAT piece of hardware is a beauty and really makes the care feel more predictable to me. Mashing the gas results in a fair amount less fishtaling. I can just hold the pedal to floor and let 'er rip!
 
1 - 20 of 39 Posts
Top