Strut braces
06-07-2010, 02:27 AM
#16
Drifting
fairly simple 333, i have about .5mm between the hood and the bar and about .5mm between the bar and the fuel rail. if it was so bend i would see either marks on the hood or marks on rail.
06-07-2010, 03:46 AM
#17
Nordschleife Master
Thank you Aaron.. OK, Posting a pic for posterity... this is how it looked...
She is under way on NEW and BETTER stuffs in there, replacing a lot of what you see, but the strut tower brace will stay for good! (although I believe I will be cutting down the mounts a little to drop the bar 1/8 inch or so...
She is under way on NEW and BETTER stuffs in there, replacing a lot of what you see, but the strut tower brace will stay for good! (although I believe I will be cutting down the mounts a little to drop the bar 1/8 inch or so...
I wouldn't mind building one of those
06-07-2010, 09:12 AM
#18
Race Director
That's the same STB that I have in my car. It's the Turbo Cup replica, probably made by Jim ("Oddjob"). Stout bar, does a great job and fits perfectly.
06-07-2010, 09:23 AM
#19
Rennlist Member
Pass me if you can!
"Excellent...hehehehehe"
06-07-2010, 10:59 AM
#21
Nordschleife Master
Just be advised, the mounts weld in place... I plan to cut mine back off to lower them about 1/8 inch or so...
shoot him a PM and see if he still has any available.. it is a very nice piece, and comes with great instructions...
06-07-2010, 04:05 PM
#23
Rennlist Member
Maybe, but possibly not much. The lower brace is between the caster blocks, right? - which is somewhat behind the shock towers. The front crossmember is below the shock towers which already keeps the frame rails and shock tower base at an equal distance.
06-07-2010, 04:16 PM
#24
Rennlist Member
Couple random thoughts on strut tower bars:
To convince yourself if a strut bar improves the stiffness of the car, try this at home. Accurately measure the distance between the two shock towers. Jack up the front of the car so both wheels are off the ground, and re-measure that same distance.
I found that on a fully caged 2750 lb track car with some tub reinforcements, the shock towers spread between 1/8” - 3/16” when the weight was taken off the wheels. And its possible that a full weight car may have even more flex.
Probably somewhat subjective if this type of body flex is detrimental to handling, and if a more rigid shock tower setup improves handling or feel. My guess is that the more dedicated the car is to track duty, the more useful a strut tower brace becomes.
When loaded with the static weight of the car, the shock towers push together. But you see diagrams of cornering loads, where it shows that the shock towers move apart when cornering hard. I have not confirmed that, but seems likely. Point is, I would argue that a well designed strut bar should be as rigid as possible in both compression and tension, to account for various static and dynamic loadings.
Any of the bars, if loaded in compression, will bow some amount based on their cross section rigidity and type of attachment (simple support or fixed support). Classical Euler’s Column Buckling theory. A well designed bar is not going to distort/bow very much.
Not uncommon for many different designs of strut bars to rub either the hood or the top of the motor (intake, fuel rail, etc) when driven, even if there is clearance when the car is stationary. Other than the bar moving some amount in compression, the hood flexes, even the stock steel ones, and the motor moves on its rubber mounts. Fiberglass hoods really start moving in the buffeting wind above 120+ mph.
To convince yourself if a strut bar improves the stiffness of the car, try this at home. Accurately measure the distance between the two shock towers. Jack up the front of the car so both wheels are off the ground, and re-measure that same distance.
I found that on a fully caged 2750 lb track car with some tub reinforcements, the shock towers spread between 1/8” - 3/16” when the weight was taken off the wheels. And its possible that a full weight car may have even more flex.
Probably somewhat subjective if this type of body flex is detrimental to handling, and if a more rigid shock tower setup improves handling or feel. My guess is that the more dedicated the car is to track duty, the more useful a strut tower brace becomes.
When loaded with the static weight of the car, the shock towers push together. But you see diagrams of cornering loads, where it shows that the shock towers move apart when cornering hard. I have not confirmed that, but seems likely. Point is, I would argue that a well designed strut bar should be as rigid as possible in both compression and tension, to account for various static and dynamic loadings.
Any of the bars, if loaded in compression, will bow some amount based on their cross section rigidity and type of attachment (simple support or fixed support). Classical Euler’s Column Buckling theory. A well designed bar is not going to distort/bow very much.
Not uncommon for many different designs of strut bars to rub either the hood or the top of the motor (intake, fuel rail, etc) when driven, even if there is clearance when the car is stationary. Other than the bar moving some amount in compression, the hood flexes, even the stock steel ones, and the motor moves on its rubber mounts. Fiberglass hoods really start moving in the buffeting wind above 120+ mph.
06-07-2010, 05:42 PM
#25
Rennlist Member
Good info Jim. What about the concept that strut bars are possibly useless if there is no triangulation? If view from the front of the car and the struts move sideways under load, that the whole assembly of two uprights with a horizontal bar across the top will just shift into a rhombus type shape. I know that some 911 guys believe that in regards to their front strut bars and hence they triangulate. With us, it's much more difficult of course with that motor thing in the way...
06-07-2010, 06:27 PM
#26
Rennlist Member
Good info Jim. What about the concept that strut bars are possibly useless if there is no triangulation? If view from the front of the car and the struts move sideways under load, that the whole assembly of two uprights with a horizontal bar across the top will just shift into a rhombus type shape. I know that some 911 guys believe that in regards to their front strut bars and hence they triangulate. With us, it's much more difficult of course with that motor thing in the way...
I wondered about this as well.
It looks like the top of the strut towers are just moving together with the bar in the middle.
Even if one argues that a strut brace does in fact stiffen up the strut towers, it would seem that it would just expose a weaker point somewhere else on the chassis, and then that would flex more.
06-07-2010, 06:34 PM
#27
Nordschleife Master
I'm too tired to even think right now so I might say something stupid:
The two towers does flex in the same direction, it's either inwards or outwards. So connecting them means the forces are working against eachother and could possibly be cancelled out with a strut brace.
Or if the majority of the forces are at the outside tower in a turn, connecting the 2 towers would distribute the load.
The two towers does flex in the same direction, it's either inwards or outwards. So connecting them means the forces are working against eachother and could possibly be cancelled out with a strut brace.
Or if the majority of the forces are at the outside tower in a turn, connecting the 2 towers would distribute the load.
06-07-2010, 07:16 PM
#28
Drifting
i have driven a few 944 and 951's with strut brances and te tell you the truth i dont think they do much at all, Well at least they dont do much you can feel. thats not to say they dont help keeping the geometry correct. but by the seat dyno, on or off i think we are kidding ourselves if we think we can feel it.
minute chances to the sway bars or toe have a far greater effect.
It must be my strut brace that is helping me in those motokhaha's, you should try one 333 they are worth 10 seconds hehehe
06-07-2010, 07:39 PM
#29
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06-07-2010, 07:43 PM
#30
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