DIY front strut bar
04-26-2004, 01:10 PM
#1
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DIY front strut bar
Well, i've already made the REAR
so now i'd like to make a solid one-piece front... but need some suggestions
should i have it mount like most e-bay bars...or build it like a neuspeed bar and mount it to where the camber kit bolts go?
so now i'd like to make a solid one-piece front... but need some suggestions
should i have it mount like most e-bay bars...or build it like a neuspeed bar and mount it to where the camber kit bolts go?
04-26-2004, 01:16 PM
#2
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Re: DIY front strut bar (DIYaccord)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DIYaccord »</TD></TR><TR><TD CLASS="quote">should i have it mount like most e-bay bars...or build it like a neuspeed bar and mount it to where the camber kit bolts go?</TD></TR></TABLE>
I think most of the civic and integra guys won't know what you're talking about... we've got a different method for attaching the UCA I think.
I would go for the neuspeed method. The actual hat of the shock doesn't exert any lateral force to speak of, compared to the anchor bolts of the control arm.
I think most of the civic and integra guys won't know what you're talking about... we've got a different method for attaching the UCA I think.
I would go for the neuspeed method. The actual hat of the shock doesn't exert any lateral force to speak of, compared to the anchor bolts of the control arm.
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04-27-2004, 08:45 PM
#9
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Re: DIY front strut bar (Greyout)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Greyout »</TD></TR><TR><TD CLASS="quote">
I think most of the civic and integra guys won't know what you're talking about... we've got a different method for attaching the UCA I think.
I would go for the neuspeed method. The actual hat of the shock doesn't exert any lateral force to speak of, compared to the anchor bolts of the control arm.</TD></TR></TABLE>
Most of the strut braces on the market are designed for bling first and function somewhere down the list after cost. The stiffest and lightest strut bar would use a strong and stiff tower extension and a straight tie bar. The material should be steel because the space limitations typical for most cars will allow for only a small diameter bar. You want to maximize EI, that is the (modulus of elasticity *second moment of area) for buckling strength and also maximize the bar stiffness AE, which is the (cross-sectional area* modulus of elasticity). If you have to put a bend in the tie bar, bend it only as much as you need to.
I think most of the civic and integra guys won't know what you're talking about... we've got a different method for attaching the UCA I think.
I would go for the neuspeed method. The actual hat of the shock doesn't exert any lateral force to speak of, compared to the anchor bolts of the control arm.</TD></TR></TABLE>
Most of the strut braces on the market are designed for bling first and function somewhere down the list after cost. The stiffest and lightest strut bar would use a strong and stiff tower extension and a straight tie bar. The material should be steel because the space limitations typical for most cars will allow for only a small diameter bar. You want to maximize EI, that is the (modulus of elasticity *second moment of area) for buckling strength and also maximize the bar stiffness AE, which is the (cross-sectional area* modulus of elasticity). If you have to put a bend in the tie bar, bend it only as much as you need to.
04-28-2004, 03:28 AM
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Re: DIY front strut bar (Outsane)
Right, it is a US car- but the brace isn't(designed for a right hand drive car). Notice how the m/c reservior is covered?
Jonny Mac-
Good thoughts. This was the only bar sold at the time that tied to the points I preferred (They do make a steel version as well). That Neuspeed brace pictured above is probably one the of the best on the market(I have a polished one sitting in my attic), but the aluminum I posted SEEMS to make the front of the car stiffer(less creaking and moaning when trying to twist the car over curbs and such
).
Jonny Mac-
Good thoughts. This was the only bar sold at the time that tied to the points I preferred (They do make a steel version as well). That Neuspeed brace pictured above is probably one the of the best on the market(I have a polished one sitting in my attic), but the aluminum I posted SEEMS to make the front of the car stiffer(less creaking and moaning when trying to twist the car over curbs and such
).
04-28-2004, 06:45 AM
#12
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Re: DIY front strut bar (jg)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jg »</TD></TR><TR><TD CLASS="quote">Right, it is a US car- but the brace isn't(designed for a right hand drive car). Notice how the m/c reservior is covered?
Jonny Mac-
Good thoughts. This was the only bar sold at the time that tied to the points I preferred (They do make a steel version as well). That Neuspeed brace pictured above is probably one the of the best on the market(I have a polished one sitting in my attic), but the aluminum I posted SEEMS to make the front of the car stiffer(less creaking and moaning when trying to twist the car over curbs and such ).</TD></TR></TABLE>
I've always been curious how much one shock/strut tower moves relative to the other tower during cornering. I guess we could build a strut bar and put a strain gauge on it to see.
Jonny Mac-
Good thoughts. This was the only bar sold at the time that tied to the points I preferred (They do make a steel version as well). That Neuspeed brace pictured above is probably one the of the best on the market(I have a polished one sitting in my attic), but the aluminum I posted SEEMS to make the front of the car stiffer(less creaking and moaning when trying to twist the car over curbs and such
).</TD></TR></TABLE>I've always been curious how much one shock/strut tower moves relative to the other tower during cornering. I guess we could build a strut bar and put a strain gauge on it to see.
04-28-2004, 06:46 AM
#13
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Re: DIY front strut bar (Outsane)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Outsane »</TD></TR><TR><TD CLASS="quote">Johnny your so smart!
what up?..Good to see you on this board..
this is Lee</TD></TR></TABLE>
Lee,
What's up? BTW, Thanks for the parts.
what up?..Good to see you on this board..
this is Lee</TD></TR></TABLE>
Lee,
What's up? BTW, Thanks for the parts.
04-28-2004, 03:18 PM
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Re: DIY front strut bar (Johnny Mac)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Johnny Mac »</TD></TR><TR><TD CLASS="quote">
I've always been curious how much one shock/strut tower moves relative to the other tower during cornering. I guess we could build a strut bar and put a strain gauge on it to see.</TD></TR></TABLE>
How would that give you displacement? Force yes, but displacement? I considered using a string pot, but sag is an issue, as it would be for a linear pot due to the length between the towers and support required. It would be good to have a way of measuring chassis deflection simply under load and then stiffening what moves the most.
I've always been curious how much one shock/strut tower moves relative to the other tower during cornering. I guess we could build a strut bar and put a strain gauge on it to see.</TD></TR></TABLE>
How would that give you displacement? Force yes, but displacement? I considered using a string pot, but sag is an issue, as it would be for a linear pot due to the length between the towers and support required. It would be good to have a way of measuring chassis deflection simply under load and then stiffening what moves the most.
04-28-2004, 05:57 PM
#15
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Re: DIY front strut bar (descartesfool)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by descartesfool »</TD></TR><TR><TD CLASS="quote">
How would that give you displacement? Force yes, but displacement? I considered using a string pot, but sag is an issue, as it would be for a linear pot due to the length between the towers and support required. It would be good to have a way of measuring chassis deflection simply under load and then stiffening what moves the most.</TD></TR></TABLE>
Actually, I can measure the vertical displacement and the axial displacement independently. Assume that the bar, which is rigidly attached to the strut tower mount on one side only (this is critical, since if the bar were fixed to both sides the bar would be an indeterminate structure and I would have to use another method). Then, the strut tie bar is a cantilever beam. Any relative vertical displacement between the two towers will result in a bending moment in the strut tie bar. A bending bridge would be used to determine this bending moment. The lateral displacement could be determined from an axial bridge. Since the loads are vertical and lateral and one side is spherical mounted, torsion would not need to be considered. The displacements are not large so coupling between the axial load and the bending moment shouldn't be very large - hence superposition of the axial and bending moment may be assumed.
How would that give you displacement? Force yes, but displacement? I considered using a string pot, but sag is an issue, as it would be for a linear pot due to the length between the towers and support required. It would be good to have a way of measuring chassis deflection simply under load and then stiffening what moves the most.</TD></TR></TABLE>
Actually, I can measure the vertical displacement and the axial displacement independently. Assume that the bar, which is rigidly attached to the strut tower mount on one side only (this is critical, since if the bar were fixed to both sides the bar would be an indeterminate structure and I would have to use another method). Then, the strut tie bar is a cantilever beam. Any relative vertical displacement between the two towers will result in a bending moment in the strut tie bar. A bending bridge would be used to determine this bending moment. The lateral displacement could be determined from an axial bridge. Since the loads are vertical and lateral and one side is spherical mounted, torsion would not need to be considered. The displacements are not large so coupling between the axial load and the bending moment shouldn't be very large - hence superposition of the axial and bending moment may be assumed.
04-28-2004, 06:02 PM
#16
Re: DIY front strut bar (Johnny Mac)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Johnny Mac »</TD></TR><TR><TD CLASS="quote">
Actually, I can measure the vertical displacement and the axial displacement independently. Assume that the bar, which is rigidly attached to the strut tower mount on one side only (this is critical, since if the bar were fixed to both sides the bar would be an indeterminate structure and I would have to use another method). Then, the strut tie bar is a cantilever beam. Any relative vertical displacement between the two towers will result in a bending moment in the strut tie bar. A bending bridge would be used to determine this bending moment. The lateral displacement could be determined from an axial bridge. Since the loads are vertical and lateral and one side is spherical mounted, torsion would not need to be considered. The displacements are not large so coupling between the axial load and the bending moment shouldn't be very large - hence superposition of the axial and bending moment may be assumed.</TD></TR></TABLE>
wow you got OWNED. those are some big words.
Actually, I can measure the vertical displacement and the axial displacement independently. Assume that the bar, which is rigidly attached to the strut tower mount on one side only (this is critical, since if the bar were fixed to both sides the bar would be an indeterminate structure and I would have to use another method). Then, the strut tie bar is a cantilever beam. Any relative vertical displacement between the two towers will result in a bending moment in the strut tie bar. A bending bridge would be used to determine this bending moment. The lateral displacement could be determined from an axial bridge. Since the loads are vertical and lateral and one side is spherical mounted, torsion would not need to be considered. The displacements are not large so coupling between the axial load and the bending moment shouldn't be very large - hence superposition of the axial and bending moment may be assumed.</TD></TR></TABLE>
wow you got OWNED. those are some big words.
04-28-2004, 06:54 PM
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Re: DIY front strut bar (Johnny Mac)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Johnny Mac »</TD></TR><TR><TD CLASS="quote">
Actually, I can measure the vertical displacement and the axial displacement independently. Assume that the bar, which is rigidly attached to the strut tower mount on one side only (this is critical, since if the bar were fixed to both sides the bar would be an indeterminate structure and I would have to use another method). Then, the strut tie bar is a cantilever beam. Any relative vertical displacement between the two towers will result in a bending moment in the strut tie bar. A bending bridge would be used to determine this bending moment. The lateral displacement could be determined from an axial bridge. Since the loads are vertical and lateral and one side is spherical mounted, torsion would not need to be considered. The displacements are not large so coupling between the axial load and the bending moment shouldn't be very large - hence superposition of the axial and bending moment may be assumed.</TD></TR></TABLE>
Hmm, sweet and simple, I like that. Then you would know for sure if it helps.
Although, on one of my street cars, I did it the lazy way...I had a section of 1.5" thin wall CrMo and a welder sitting around, we got drunk, and somehow it got welded to the chassis real permanent like. Luckily it was in the rear. Never could get that new TV home though
Actually, I can measure the vertical displacement and the axial displacement independently. Assume that the bar, which is rigidly attached to the strut tower mount on one side only (this is critical, since if the bar were fixed to both sides the bar would be an indeterminate structure and I would have to use another method). Then, the strut tie bar is a cantilever beam. Any relative vertical displacement between the two towers will result in a bending moment in the strut tie bar. A bending bridge would be used to determine this bending moment. The lateral displacement could be determined from an axial bridge. Since the loads are vertical and lateral and one side is spherical mounted, torsion would not need to be considered. The displacements are not large so coupling between the axial load and the bending moment shouldn't be very large - hence superposition of the axial and bending moment may be assumed.</TD></TR></TABLE>
Hmm, sweet and simple, I like that. Then you would know for sure if it helps.
Although, on one of my street cars, I did it the lazy way...I had a section of 1.5" thin wall CrMo and a welder sitting around, we got drunk, and somehow it got welded to the chassis real permanent like. Luckily it was in the rear. Never could get that new TV home though
04-28-2004, 08:10 PM
#18
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Re: DIY front strut bar (Johnny Mac)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Johnny Mac »</TD></TR><TR><TD CLASS="quote">
Since the loads are vertical and lateral and one side is spherical mounted, torsion would not need to be considered. </TD></TR></TABLE>
A lot of bars aren't spherically mounted...
Aluminum vs. steel is a non-issue IMO. The only thing that matters is the design of the bracket. The shorter the height of the bracket (where it mounts to the cross-bar in relation to the strut tower) the better, to minimize deformation of the strut towers and the brackets themselves in the axial direction. Solid steel rod vs. hollow extruded aluminum cross-member isn't going to make a lick of difference. The sheet metal in the body is going to deform a hell of a lot more. Any buckling or compression displacement of the bar is negligible compared to the body.
The goal is not to find the strongest and stiffest "bar", its to find the one that will minimize deformation of the brackets and the body. Stay away from the stuff with flimsy and/or tall brackets.
The truth is that pretty much anything will do the job, and the difference between them all isn't much without at least poly if not full spherical suspension bushings.
Since the loads are vertical and lateral and one side is spherical mounted, torsion would not need to be considered. </TD></TR></TABLE>
A lot of bars aren't spherically mounted...
Aluminum vs. steel is a non-issue IMO. The only thing that matters is the design of the bracket. The shorter the height of the bracket (where it mounts to the cross-bar in relation to the strut tower) the better, to minimize deformation of the strut towers and the brackets themselves in the axial direction. Solid steel rod vs. hollow extruded aluminum cross-member isn't going to make a lick of difference. The sheet metal in the body is going to deform a hell of a lot more. Any buckling or compression displacement of the bar is negligible compared to the body.
The goal is not to find the strongest and stiffest "bar", its to find the one that will minimize deformation of the brackets and the body. Stay away from the stuff with flimsy and/or tall brackets.
The truth is that pretty much anything will do the job, and the difference between them all isn't much without at least poly if not full spherical suspension bushings.
04-28-2004, 10:44 PM
#19
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Re: DIY front strut bar (MightyMouseTech)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MightyMouseTech »</TD></TR><TR><TD CLASS="quote">
Hmm, sweet and simple, I like that. Then you would know for sure if it helps.
Although, on one of my street cars, I did it the lazy way...I had a section of 1.5" thin wall CrMo and a welder sitting around, we got drunk, and somehow it got welded to the chassis real permanent like. Luckily it was in the rear. Never could get that new TV home though </TD></TR></TABLE>
Yeah, I know it's going beyond where this topic was intended - the topic is supposed to be DIY. If I were a manufacturer though, I would want to know how much deflection was occuring in the strut/shock towers for a couple of reasons. First, if the deflection was not large enough to worry about, then I would consider not marketing such a product. Personally, I'm not into bling for the sake of putting show-n-no-go parts on my car. It's got to do something otherwise my hard earned cash can go to buy something that will. Secondly, if there was enough deflection where I could see that stiffening the towers was going improve some aspect of my car's handling, then I would want to make sure my design actually improved the stiffness and by how much. To accomplish both of these tasks I would need to quantify what's deflecting and how much. This is a perfect area for strain gaging. Sorry about the techno bs.
Hmm, sweet and simple, I like that. Then you would know for sure if it helps.
Although, on one of my street cars, I did it the lazy way...I had a section of 1.5" thin wall CrMo and a welder sitting around, we got drunk, and somehow it got welded to the chassis real permanent like. Luckily it was in the rear. Never could get that new TV home though
</TD></TR></TABLE>Yeah, I know it's going beyond where this topic was intended - the topic is supposed to be DIY. If I were a manufacturer though, I would want to know how much deflection was occuring in the strut/shock towers for a couple of reasons. First, if the deflection was not large enough to worry about, then I would consider not marketing such a product. Personally, I'm not into bling for the sake of putting show-n-no-go parts on my car. It's got to do something otherwise my hard earned cash can go to buy something that will. Secondly, if there was enough deflection where I could see that stiffening the towers was going improve some aspect of my car's handling, then I would want to make sure my design actually improved the stiffness and by how much. To accomplish both of these tasks I would need to quantify what's deflecting and how much. This is a perfect area for strain gaging. Sorry about the techno bs.
04-28-2004, 10:52 PM
#20
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Re: DIY front strut bar (sackdz)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sackdz »</TD></TR><TR><TD CLASS="quote">
A lot of bars aren't spherically mounted...
Aluminum vs. steel is a non-issue IMO. The only thing that matters is the design of the bracket. The shorter the height of the bracket (where it mounts to the cross-bar in relation to the strut tower) the better, to minimize deformation of the strut towers and the brackets themselves in the axial direction. Solid steel rod vs. hollow extruded aluminum cross-member isn't going to make a lick of difference. The sheet metal in the body is going to deform a hell of a lot more. Any buckling or compression displacement of the bar is negligible compared to the body.
The goal is not to find the strongest and stiffest "bar", its to find the one that will minimize deformation of the brackets and the body. Stay away from the stuff with flimsy and/or tall brackets.
The truth is that pretty much anything will do the job, and the difference between them all isn't much without at least poly if not full spherical suspension bushings.</TD></TR></TABLE>
Some strut bar assemblies do not use spherical connections. Actually, I would prefer not to have a spherical connection in the bar, since the spherical will tend to reduce the overall stiffness of the strut bar. The only thing the spherical connection would be used for is testing the displacement in the towers. After this is known, then engineer the strut bar for stiffness that will reduce the unwanted deflection.
A lot of bars aren't spherically mounted...
Aluminum vs. steel is a non-issue IMO. The only thing that matters is the design of the bracket. The shorter the height of the bracket (where it mounts to the cross-bar in relation to the strut tower) the better, to minimize deformation of the strut towers and the brackets themselves in the axial direction. Solid steel rod vs. hollow extruded aluminum cross-member isn't going to make a lick of difference. The sheet metal in the body is going to deform a hell of a lot more. Any buckling or compression displacement of the bar is negligible compared to the body.
The goal is not to find the strongest and stiffest "bar", its to find the one that will minimize deformation of the brackets and the body. Stay away from the stuff with flimsy and/or tall brackets.
The truth is that pretty much anything will do the job, and the difference between them all isn't much without at least poly if not full spherical suspension bushings.</TD></TR></TABLE>
Some strut bar assemblies do not use spherical connections. Actually, I would prefer not to have a spherical connection in the bar, since the spherical will tend to reduce the overall stiffness of the strut bar. The only thing the spherical connection would be used for is testing the displacement in the towers. After this is known, then engineer the strut bar for stiffness that will reduce the unwanted deflection.
04-28-2004, 11:31 PM
#21
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Re: DIY front strut bar (Johnny Mac)
sackdz, jmac was only saying using a spherical mount to measure the deflection/displacement. not an ideal system.
hey john, just remember, not everyone has taken a first year course in statics to understand what youre saying.
hey john, just remember, not everyone has taken a first year course in statics to understand what youre saying.
04-29-2004, 05:09 AM
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Re: DIY front strut bar (Johnny Mac)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Johnny Mac »</TD></TR><TR><TD CLASS="quote">
Actually, I can measure the vertical displacement and the axial displacement independently. Assume that the bar, which is rigidly attached to the strut tower mount on one side only (this is critical, since if the bar were fixed to both sides the bar would be an indeterminate structure and I would have to use another method). </TD></TR></TABLE>
If you first build the linking structure, in this case the strut bar, then you can use strain guages on the linking structure to measure forces in the beam due to bending and compute displacement. I have never seen results of measurements done this way on a chassis and would be curious to see something real vs theoretical. Displacement is the main parameter to be measured as it affects suspension geometry, in this case mostly camber under load. It would be preferable to have a method to measure displacement in the body without having to first build the linking structure. Strain guages are commonly used to measure forces in damper shafts thus allowing one to compute loads on the tires. Have you actually done this for chassis movement or is it just theory?
Actually, I can measure the vertical displacement and the axial displacement independently. Assume that the bar, which is rigidly attached to the strut tower mount on one side only (this is critical, since if the bar were fixed to both sides the bar would be an indeterminate structure and I would have to use another method). </TD></TR></TABLE>
If you first build the linking structure, in this case the strut bar, then you can use strain guages on the linking structure to measure forces in the beam due to bending and compute displacement. I have never seen results of measurements done this way on a chassis and would be curious to see something real vs theoretical. Displacement is the main parameter to be measured as it affects suspension geometry, in this case mostly camber under load. It would be preferable to have a method to measure displacement in the body without having to first build the linking structure. Strain guages are commonly used to measure forces in damper shafts thus allowing one to compute loads on the tires. Have you actually done this for chassis movement or is it just theory?
04-29-2004, 10:47 AM
#23
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Re: DIY front strut bar (Tyson)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tyson »</TD></TR><TR><TD CLASS="quote">sackdz, jmac was only saying using a spherical mount to measure the deflection/displacement. not an ideal system.
hey john, just remember, not everyone has taken a first year course in statics to understand what youre saying.</TD></TR></TABLE>
I know and if you go back to my first post on the topic, you would see that I tried to keep it simple. However, that post you're referring to was a bit too much on the technobabble. KISS - A principle we should all live by.
hey john, just remember, not everyone has taken a first year course in statics to understand what youre saying.</TD></TR></TABLE>
I know and if you go back to my first post on the topic, you would see that I tried to keep it simple. However, that post you're referring to was a bit too much on the technobabble. KISS - A principle we should all live by.
04-29-2004, 10:54 AM
#24
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Re: DIY front strut bar (descartesfool)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by descartesfool »</TD></TR><TR><TD CLASS="quote">
If you first build the linking structure, in this case the strut bar, then you can use strain guages on the linking structure to measure forces in the beam due to bending and compute displacement. I have never seen results of measurements done this way on a chassis and would be curious to see something real vs theoretical. Displacement is the main parameter to be measured as it affects suspension geometry, in this case mostly camber under load. It would be preferable to have a method to measure displacement in the body without having to first build the linking structure. Strain guages are commonly used to measure forces in damper shafts thus allowing one to compute loads on the tires. Have you actually done this for chassis movement or is it just theory?</TD></TR></TABLE>
Well, I haven't done this for a car yet, but here at Robinson Helicopter we strain gage complete helicopters (including the rotor blades) and run different flight conditions to see how the components are stressed. We use the data to run fatigue tests on all the critical components to make sure we keep our birds in the sky. We use a 2 separate 32 channel Dataq systems to measure this data. It is amazing how consistent the data comes out for the same flight conditions. A systems like this could be constructed to do the same on cars. I would like to locate a decent price data acquisition systems for doing my aerodynamics work and for stuff like this strut tower bar.
If you first build the linking structure, in this case the strut bar, then you can use strain guages on the linking structure to measure forces in the beam due to bending and compute displacement. I have never seen results of measurements done this way on a chassis and would be curious to see something real vs theoretical. Displacement is the main parameter to be measured as it affects suspension geometry, in this case mostly camber under load. It would be preferable to have a method to measure displacement in the body without having to first build the linking structure. Strain guages are commonly used to measure forces in damper shafts thus allowing one to compute loads on the tires. Have you actually done this for chassis movement or is it just theory?</TD></TR></TABLE>
Well, I haven't done this for a car yet, but here at Robinson Helicopter we strain gage complete helicopters (including the rotor blades) and run different flight conditions to see how the components are stressed. We use the data to run fatigue tests on all the critical components to make sure we keep our birds in the sky. We use a 2 separate 32 channel Dataq systems to measure this data. It is amazing how consistent the data comes out for the same flight conditions. A systems like this could be constructed to do the same on cars. I would like to locate a decent price data acquisition systems for doing my aerodynamics work and for stuff like this strut tower bar.
04-29-2004, 11:34 AM
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Re: DIY front strut bar (Johnny Mac)
I use the real cheap DataQ stuff. $25 buys you a 4 channel unit with their lite software. I have gotten all my buddies to get one of these for playing around with.
http://www.dataq.com/194.htm
For $50 or even $99, you get up to 8 channels and USB. I think these systems can't be beat.
http://www.dataq.com/products/startkit/di148.htm
For in car logger, I use the Race Technology one, model DL-90. It only has two analog channels above those for the built-in accelerometers, but you can certaily log strut bar info. Unlike the mini DataQ units, you don't need a PC connected at all times to store data. GPS based track map is nice. They also have a new unit with 8 analog inputs, the DL1, for a couple of hundred dollars more.
http://www.race-technology.com....html
All this to see where the strut bar is needed is better determined with measurements.
Based on the picture above, I fail to see how that Neuspeed unit would be very stiff. That is one long lever arm at each end. As others have said, make bar straight as possible. The points you want to keep from moving is the center of the shock and the top of the A-arm. I would bolt directly to top of the A-arm if possible.
Also the stock front ITR bar was good enough for Realtime to win a few championships, so it must be good enough to do the job. Use that as a model to start with. As you can see in the pictures, it bolts to the body above the A-arm and shock tower bolts.
Modified by descartesfool at 3:50 PM 4/29/2004
http://www.dataq.com/194.htm
For $50 or even $99, you get up to 8 channels and USB. I think these systems can't be beat.
http://www.dataq.com/products/startkit/di148.htm
For in car logger, I use the Race Technology one, model DL-90. It only has two analog channels above those for the built-in accelerometers, but you can certaily log strut bar info. Unlike the mini DataQ units, you don't need a PC connected at all times to store data. GPS based track map is nice. They also have a new unit with 8 analog inputs, the DL1, for a couple of hundred dollars more.
http://www.race-technology.com....html
All this to see where the strut bar is needed is better determined with measurements.
Based on the picture above, I fail to see how that Neuspeed unit would be very stiff. That is one long lever arm at each end. As others have said, make bar straight as possible. The points you want to keep from moving is the center of the shock and the top of the A-arm. I would bolt directly to top of the A-arm if possible.
Also the stock front ITR bar was good enough for Realtime to win a few championships, so it must be good enough to do the job. Use that as a model to start with. As you can see in the pictures, it bolts to the body above the A-arm and shock tower bolts.
Modified by descartesfool at 3:50 PM 4/29/2004