I think its the most noticeable after you drive it with the subs in for a while, and then get into a car without them. Then you realize how bad it actually is.
Not quite as stiff as I'd have thought
- Thread starter Mr.Soup
- Start date
But how much higher is one tire than the other? Before the subs, the front tire would be pretty high before the back tire was off. Now, there isn't much difference.
Keep in mind sub-frame connectors will stiffen only the floorboards section of the car but will do nothing to stiffen the chassis on the front or rear end body structure. There are huge gaps on some critical joints which will flex and fatigue the metal over time. Sub-frames do almost nothing for twist between the axles and only work to reduce deflection (bending). I have done substantial chassis reinforcement to my 04 and have extensive knowledge about the chassis structure and how this car is assembled. Think about what happens to the chassis in a 600 hp drag car running slicks and gears when you do a 5000 rpm clutch dump and you can see how much it torques the chassis which will loosen up rather quickly. Plus the spot welds are far and few between. The SN95 does have fairly thick metal on some critical areas and look absolutely stout compared to the "Swiss Cheese" Fox chassis but it gained a few hundred pounds in the process. The S197 chassis has been stiffened up over the SN95 to the same degree the SN95 is over the Fox chassis.
The Hans Racecraft and GoldenWest subs will add substantial stiffness to the chassis over the rectangular section tubing used on most sub-frame kits plus you can jack the car up NASCAR style. I was astounded by the difference in ride quality leaving the parking after the Hans were installed on my car. Another thing to consider is most sub-frames beef up the inner seat mounts which give the illusion they are doing more then they really are by transmitting more of the road shock to your fanny. Not saying sub-frames are not worth it, quite the contrary. The rocker panels and the roof rail are the only members tying both ends of the car together. The subs augment the rocker panels ......I won't even broach the topic of the integrity of a vert chassis :uh oh: Add coilovers and you just opened up another can of worms. Mustangs is not exclusive to this problem :nonono:
The Hans Racecraft and GoldenWest subs will add substantial stiffness to the chassis over the rectangular section tubing used on most sub-frame kits plus you can jack the car up NASCAR style. I was astounded by the difference in ride quality leaving the parking after the Hans were installed on my car. Another thing to consider is most sub-frames beef up the inner seat mounts which give the illusion they are doing more then they really are by transmitting more of the road shock to your fanny. Not saying sub-frames are not worth it, quite the contrary. The rocker panels and the roof rail are the only members tying both ends of the car together. The subs augment the rocker panels ......I won't even broach the topic of the integrity of a vert chassis :uh oh: Add coilovers and you just opened up another can of worms. Mustangs is not exclusive to this problem :nonono:
:cuss: You beat me to it.
what is the diiference between subframe connectors and jacking rails? What are jacking rails?
The names pretty much say it all. Subframe connectors tie the front and rear subframes of the uni-body together to make it act more like a one piece frame. Jacking rails are typically, maybe always, welded to subframe connectors and the pinch weld were the floor pan meets the body. Basically they spread the load from the car on the jack so that you can easily jack up the car. This helps alot, especially on lowered cars where getting a jack under the car is difficult.
I just had them installed on my '99 Cobra. There is a noticeable difference, but it didn't help with the cowl shake or anything. I don't really remember noticing a huge difference on my '95 coupe when I had them installed on it either, but then after driving others, I realized that it does really help.
With the top down, it is great though.
There is no other rattle in the car, other than the top where you clamp it down.
I would like to know what else I could do to help with cowl shake. This is my first convertible, so I had no idea what to expect and don't know what is considered normal.
With the top down, it is great though.
There is no other rattle in the car, other than the top where you clamp it down.I would like to know what else I could do to help with cowl shake. This is my first convertible, so I had no idea what to expect and don't know what is considered normal.
a strut tower brace might help
cobraracer46
Banned
I dont think a strut tower brace will solve the cowl shake problem. My Cobra had a cowl shake problem and now the problem is gone. My Cobra convertible deos not have a strut tower brace. I got rid of the cowl shake problem in my car with the Griggs frame kit. The frame kit requires a lot of interior floor pan cutting and welding to install the upper subframes and bulk head stiffeners that connect to the lower subframes, but the results are worth it. Griggs claims that chassis stiffness in bending mode is increased by 1500%
Most people on this board will tell you that the Griggs frame kit is over kill and is only needed on something like a open track or road race mustang, but this is exactly what the mustang convertible needs to stiffen it up. By the way, jacking rails, ladder rails only serve to add weight without adding any real stiffness.
While the frame kit itself is not expensive, the labor to install it not cheap since it taks atleast 8 hours to install it. Thankfully I saved a ton of money by doing all of the cutting and welding my self.
eh, the strut tower brace connects the firewall to the strut towers, which does help to reduce cowl shake. Probably not a huge increase, but not bad for the price and effort
I just had to say this, stb braces work well, and are cheap for what they do, i would not even drive my car if it wasnt on ,I really feel bad for the people that havent experienced the positve effects it has and most wont get the chance because one of the first mods people do are cai's and one of the most popular brands doesnot allow for the stb mod ....
We all know that you have a stronger subframe kit, cause you tell us every chance you get. For someone who doesn't, they can either rip out what they have and waste $200+, buy yours for $350 and spend another $600+ on the install($1100+ if you can't add), or buy a $150 STB that they can easily install themselves.
oke: Most people don't have a welder. The jacking rails are not intended to increase rigidity, just give you a nice place to put a jack.
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One source of cowl shake is likely from the lack of corner bracing on the upper radiator support. If you remove the radiator and look carefully at the sheet metal construction you will be stunned by how little structure there is and the lack of bracing. When the car hits a bump the overhang of the front sheet metal out in front of the wheels will amplify side-to-side shaking. A strut tower brace may help a little but the most effective method would be to add reinforcement plates and seam weld the upper radiator brace.
Interesting. I may try the strut tower brace for starters. I am not interested in yanking off the MM SFCs I had installed, but reinforcement in other areas is an option. I do have a MIG, but only use it on parts that are not "critical". I might take a crack at welding in some other reinforcements now that the SFCs are installed. Of course, I am no engineer. It took me half a day just to make mounts for my radiator fan for my Sport Trac today.
cobraracer46
Banned
We all know that you have a stronger subframe kit, cause you tell us every chance you get. For someone who doesn't, they can either rip out what they have and waste $200+, buy yours for $350 and spend another $600+ on the install($1100+ if you can't add), or buy a $150 STB that they can easily install themselves.
Unless a cobra has a set of Kenny brown subframe connectors ( the worst sub frame connectors on the market by far) there is no need to rip out the subframes that are already on the car to install the upper half of the Griggs frame kit since the Griggs system uses a conventional sub frame for the lower underside of the car. My car has the Global west lower subframes( without the ladder bar crap) and at the middle, the Globalwest subframes are welded to the Griggs upper frame rails that are sunk in and welded to the upper part of the floor pan.
Still, more exspensive than a STB. Just in the parts too. Unless the car is going to be tracked heavily, overkill IMO.
cobraracer46
Banned
Overkill is exactly what is needed when it comes to stiffening the mustang convertible.
That's not the definition of overkill. That means more than needed. Stiff as a wet noodle, I get it. Part of the reason I bought a coupe in the first place.
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