Rear Strut Tower Bar Installed
09-17-07, 04:34 PM
#1
Rear Strut Tower Bar Installed
Finally got around to doing it. I thought it was going to be a pain in the @$$; having to take out the shocks and whatnot. Apparently not 
Drilled 2 holes through each of the strut towers on the outside edge, and 2 on the back trunk deck. I originally wanted to just screw them in until I get my LSD rear put on and add nuts to it, but when I jacked the car up, I hopped in the backseat and looked at how much metal I drilled through on the trunk deck. What? I see ground! I slid under the car and look up. Holy moley I dont need to take anything off, the holes for the towers were far enough for me to stick a couple extensions on an 11mm socket and get my nuts in there nice and tight (Don't get any ideas with that last sentence people...)
Got the sister figure of the family to hold the screws tight while I was wrenching away underneath. Lo and behold people, I give you an installed CP Racing Rear Strut Bar:
I have an extra set of rear speaker covers that I am going to cut up and see where I need to cut the slot and hole for the bar to pass through, and keep the rear looking as stock as possible.
Haven't driven it yet, and I dont expect to see anything as I am riding on pretty much blown shocks to begin with.
Drilled 2 holes through each of the strut towers on the outside edge, and 2 on the back trunk deck. I originally wanted to just screw them in until I get my LSD rear put on and add nuts to it, but when I jacked the car up, I hopped in the backseat and looked at how much metal I drilled through on the trunk deck. What? I see ground! I slid under the car and look up. Holy moley I dont need to take anything off, the holes for the towers were far enough for me to stick a couple extensions on an 11mm socket and get my nuts in there nice and tight (Don't get any ideas with that last sentence people...)Got the sister figure of the family to hold the screws tight while I was wrenching away underneath. Lo and behold people, I give you an installed CP Racing Rear Strut Bar:
I have an extra set of rear speaker covers that I am going to cut up and see where I need to cut the slot and hole for the bar to pass through, and keep the rear looking as stock as possible.
Haven't driven it yet, and I dont expect to see anything as I am riding on pretty much blown shocks to begin with.
09-17-07, 06:05 PM
#5
Thanks man^
I don't think anyone else makes the rear strut bars, so I took some measurement beforehand in case some of you guys wanted to make one of your own.
The screw holes for the strut tower and bottom plates are non-existent on the FB, so you will have to drill for bolts/nuts to go in, so that is up to you if you want to follow the measurements on how far they are from the end since it wont really matter. Here ya go:
All in Inches
Side to side – 43.5
Big bar – 37.75
Bottom rectangle – 2.5
Bottom holes – 3/8th wide. ¼ from far end
Small bar – 6.25
Strut mount – 3.25
Strut tower holes – (2) 3/8th, (1) 2
Strut tower hole edge – ½ from far end
I don't think anyone else makes the rear strut bars, so I took some measurement beforehand in case some of you guys wanted to make one of your own.
The screw holes for the strut tower and bottom plates are non-existent on the FB, so you will have to drill for bolts/nuts to go in, so that is up to you if you want to follow the measurements on how far they are from the end since it wont really matter. Here ya go:
All in Inches
Side to side – 43.5
Big bar – 37.75
Bottom rectangle – 2.5
Bottom holes – 3/8th wide. ¼ from far end
Small bar – 6.25
Strut mount – 3.25
Strut tower holes – (2) 3/8th, (1) 2
Strut tower hole edge – ½ from far end
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09-17-07, 07:04 PM
#9
FB+FC=F-ME
I have a CP bar too,lucky I got it before they hit the sh*t.
I just cut some slots in the plastic covers and called it a day.It only gets in the way when I need to haul something big,which isnt often.
As with the RB front bar I have,there are no discearnable changes in the feel of the car.Im sure theres some rigidity added,and I would hope the advantage overweighs the weight penalty of adding the bars......but its not a mod your going to notice.And if you do,its likely to be your mind telling you something changed....in other words,a big fat placebo.
I just cut some slots in the plastic covers and called it a day.It only gets in the way when I need to haul something big,which isnt often.
As with the RB front bar I have,there are no discearnable changes in the feel of the car.Im sure theres some rigidity added,and I would hope the advantage overweighs the weight penalty of adding the bars......but its not a mod your going to notice.And if you do,its likely to be your mind telling you something changed....in other words,a big fat placebo.
09-17-07, 07:54 PM
#10
I have a CP bar too,lucky I got it before they hit the sh*t.
I just cut some slots in the plastic covers and called it a day.It only gets in the way when I need to haul something big,which isnt often.
As with the RB front bar I have,there are no discearnable changes in the feel of the car.Im sure theres some rigidity added,and I would hope the advantage overweighs the weight penalty of adding the bars......but its not a mod your going to notice.And if you do,its likely to be your mind telling you something changed....in other words,a big fat placebo.
I just cut some slots in the plastic covers and called it a day.It only gets in the way when I need to haul something big,which isnt often.
As with the RB front bar I have,there are no discearnable changes in the feel of the car.Im sure theres some rigidity added,and I would hope the advantage overweighs the weight penalty of adding the bars......but its not a mod your going to notice.And if you do,its likely to be your mind telling you something changed....in other words,a big fat placebo.
09-18-07, 12:02 AM
#13
Thx for the compliment aws. This is going to be on my street/autocross car. I cant put a cage in it because of the rear seats.
09-18-07, 03:32 PM
#19
Long answer will be drawn out. I don't want to hijack your thread
I don't want to say something against your setup. Please do not take it that way. Your car is looking great and the bar absolutely does not hurt anything being there. Keep up the hard work.
-billy
09-18-07, 03:55 PM
#20
Short answer, Yes, because they are shocks.
Long answer will be drawn out. I don't want to hijack your thread
I don't want to say something against your setup. Please do not take it that way. Your car is looking great and the bar absolutely does not hurt anything being there. Keep up the hard work.
-billy
Long answer will be drawn out. I don't want to hijack your thread
I don't want to say something against your setup. Please do not take it that way. Your car is looking great and the bar absolutely does not hurt anything being there. Keep up the hard work.
-billy
09-19-07, 10:28 AM
#21
OK then...... Suspension systems have pickup or pivot or mounting points. These points may flex and move a bit during the suspension travel. When points like these move around it dynamically changes suspension characteristics. Problem with this is that the changes are not necessarily measurable nor repeatable. When tuning anything from a carburetor to suspension you must be able to reproduce and anticipate the reaction to changes. Other wise you are "pissing in the wind" or " Chasing your tail".
Since some of the first things we do to improve the suspension characteristics is to add stiffer parts like bars or springs we put more stresses and forces than the vehichles were originally designed for. This is where stiffening comes in. The use of seam welding or bracing is to stiffen the pickup points so they do not move around. Bracing is done to an area or next to an area that is considered a pick up point that dictates a suspension characteristic.
On the front we use a "stut" bar in order to keep the tower from moving around. The tower is the upper suspension mount that dictates the caster and more so the camber angle of the vehicle. The forces put on this area are done so along the strut housing centerline which is at an angle. If this point moves during suspension bump your camber and/or caster angels will be dynamically changing at differing amounts depending on the forces. In other words, the harder you turn in the more it may move. A strut brace simply ties two points together effectively transferring any forces through both of them. To move one the forces must move both. Mcpherson strut towers are notoriously high and far away from other chassis structure. This makes them venerable to flex.
Understanding those points above we can look at the rear. First thing I would bring up is the structure where the shocks mount is cone shaped and within 6 inches of major chassis structure that goes in many planes. This means they are supported very well. Second point I would bring up is that the shock moving laterally at its top mounting point would not change anything. Third point is that the shock mounts straight up and down. Any brace used would need to go from the shock mount to the roof. Fourth point is that the rubber bushings used to locate the top of the shocks will flex way before any metal structure. Fifth point is that the shock is not strong enough to force the chassis to move. Think about it, can you move the chassis up and down by hand? can you move the shock up and down by hand?
One may want to argue a motion ratio change by the top of the shock moving but until someone cad models the rear of a first gen and calculates the effects of the upper mount moving 1" laterally and comes up with a change of more than 1% then I will stand by my statement.
Now there are better changes that will effect the suspension. Hard mounting the rear upper shock mount will remove the bushing compliance. This could allow the shock to work a bit better if you have added stiffer shocks. Bracing the area where the springs sit can be a good idea and is the number one spot where the rear down tubes on roll cages go.
-billy
09-19-07, 03:38 PM
#25
I had the idea to fab a rear tower brace avbout a year ago and talked it over with a couple members (i believe one was aws) and we all came to the conclusion that it would
1) add weight
2) limit hatch space
3) not add much performance since the rear floor pan is only about 6 inches lower then the top of the towers.
Bar looks really good from the pics, maybe use the same thoughts and ideas and create a front strut tower brace from scratch, that would be cool.
1) add weight
2) limit hatch space
3) not add much performance since the rear floor pan is only about 6 inches lower then the top of the towers.
Bar looks really good from the pics, maybe use the same thoughts and ideas and create a front strut tower brace from scratch, that would be cool.