GReddy strut tower bar installed
01-26-2005, 10:31 PM
#26
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Originally Posted by Spin9k
**That's the point of this discussion** not to flame you!
Originally Posted by Spin9k
only the stiffness of the bar in pulling and compression loads is important. So if the bar bends (not the joint area which is screwed tight to the strut tower) that is bad. Otherwise, it doesn't matter. Having a 'joint' does not in and of itself reduce or contribute to the bars stiffness in compression and in pulling, but the material and shape of the bar does.
Originally Posted by SpinK9
the connection between the bar and the tower connector can be welded solid or be a joint. It doesn't effect the strut bar function given they are engineered to the forces they must withstand. Many bars are jointed - look at the MazdaSpeed one, for example, why would MazdaSpeed (and may other reputable companies) create a worse than stock bar - they wouldn't.
Originally Posted by Spin9k
your saying the joint is more complex. It depends I guess, welding, setting up an accurate jig, that's pretty complex. Simple assemble is well, pretty un-complex. In any case, the joint does have advantages. 1st, you can assemble it easily. 2nd, assembly allows making the bar itself of a completely different material than the tower connector... like steel or aluminum at the tower, and aluminum or carbon fiber for the bar, etc. It is difficult/impossible to weld these materials obviously. This can result in weight savings, not gain. 3rd, you can un-connect the bar and lift it up for easiler engine access, if needed, rather than disassembling the bar from the tower. These are some really nice advantages!
01-27-2005, 10:17 AM
#28
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My understanding (not that I am an expert) is that constraining this type of movement is not part of the strut bar's intended function. I agree that its not intuitive that is so, but I've read that on several occasions. I don't have the ME background to understand why however.
jds
jds
Originally Posted by globi
Don't worry I'm not that sensitive.
If the pulling and compression loads are really the only loads that are important then I'd agree. But at least as I understand it, you also don't want that one tower moves downwards whereas the other moves up, which definitely happens when you brake and corner at the same time. If there's a joint you can't really diminish that reaction. Think of a parallelogram. Any suspension works better if a chassis is stiffer.
If the pulling and compression loads are really the only loads that are important then I'd agree. But at least as I understand it, you also don't want that one tower moves downwards whereas the other moves up, which definitely happens when you brake and corner at the same time. If there's a joint you can't really diminish that reaction. Think of a parallelogram. Any suspension works better if a chassis is stiffer.
01-27-2005, 10:58 AM
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Originally Posted by bureau13
My understanding (not that I am an expert) is that constraining this type of movement is not part of the strut bar's intended function. I agree that its not intuitive that is so, but I've read that on several occasions. I don't have the ME background to understand why however.
So if it makes sense for the chassis to be as stiff as possible in order for the suspension to work better, it would also make sense to have a jointless strutbar (possibly in combination with a jointless strutbar on the bottom).
http://www.e30m3performance.com/myth...bar_theory.htm
01-27-2005, 05:02 PM
#32
Momentum Keeps Me Going
Originally Posted by globi
Figure 1 in this article doesn't show the vertical forces. The towers are really exposed to horizontal and vertical forces at the same time. A jointless strutbar can only take horizontal forces.
So if it makes sense for the chassis to be as stiff as possible in order for the suspension to work better, it would also make sense to have a jointless strutbar (possibly in combination with a jointless strutbar on the bottom).
http://www.e30m3performance.com/myth...bar_theory.htm
So if it makes sense for the chassis to be as stiff as possible in order for the suspension to work better, it would also make sense to have a jointless strutbar (possibly in combination with a jointless strutbar on the bottom).
http://www.e30m3performance.com/myth...bar_theory.htm
The RX-8 'Big Book' has this to say on the use and function of our stock strut tower bar. And I quote:
page 67: "A steel tower bar ties the top mounts together. It's primary function is to provide stiffness to the upper opening of the engine compartment."
page 71: "A tower bar ties together the front suspension's top shocks mounts, bracing the engine compartment opening."
page 124: "The front lower opening was thus strengthened....Enter practical considerations...Therefore, the [lower] transverse member's ends are bent downward, reducing its effectiveness as a brace. So a tubular rod tying the tops of the spring/shock absorber towers together is standard on all RX-8 models to increase front end stiffness."
And globi, I note that the Japan only version of the MazdaSpeed strut bar is welded tight as a tick into a 4-pt brace. Differently executed, but similar is the the Autoexe bar, also a solid 4-pt bar. Both use triangle-design bracing, the best and truest type for stiffness.
Sigh, so much information, so few engineering explainations
But so much fun trying to figure it all out, reverse engineering style
!
Last edited by Spin9k; 01-27-2005 at 07:20 PM.
01-27-2005, 07:18 PM
#34
Momentum Keeps Me Going
Originally Posted by Thetitanium8
I would like to see a pic with engine cover on if you can plz.
01-27-2005, 07:28 PM
#35
Mr. Skinny
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Originally Posted by Spin9k
If you mean the two braces I mentioned, here you go 1st the Mazdaspeed, but the cover doesn't fit, 2nd the Autoexec with see-thru cover to illustrate, 3rd the whole Autoexe kit on the 8 to show where it goes...
01-28-2005, 05:55 PM
#38
Guys to add a point, one of the biggest advantages of adding an after market front strut brace is the ability to also have a master cylinder bace. On hard braking the master cylinder actually moves! The firewall is kind of flimsey! Because of that a 4 point brace may put to much pressure on your windshield (as in help crack/break it), so be careful with that one. Changing front strut braces welll---- ok but adding a master cylinder brace --man you can tell a differance.
olddragger
olddragger
01-28-2005, 08:32 PM
#39
Momentum Keeps Me Going
Originally Posted by olddragger
... Changing front strut braces welll---- ok but adding a master cylinder brace --man you can tell a differance. olddragger
Now it's your turn...
01-29-2005, 10:04 AM
#40
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Originally Posted by Spin9k
Ok I hear you, but this is what I hear all the time about the brake brace... that there is a "difference". So what exactly IS the difference? Is it different because you 'think' it better cause it cost money or what?l Can you put it experiential words about braking on a track, or on the street... do you stop faster... I mean the brakes certainly feel tight to me without it, so what's the dif? It just can't picture how it's going to feel so mightly special....
I'd say as long as you keep your suspension stock, there's not much point in stiffening the body up, but if you had racing coil-overs you probably would notice a difference between stock body and strutted body on a track.
01-30-2005, 01:08 PM
#42
Momentum Keeps Me Going
I understand the benefits of strut braces, body braces and the like, I just wondered if olddragger could put into words the actual braking experience/benefits he was talking about with the added brake master cylinder brace he mentioned.
Originally Posted by olddragger
---- ok but adding a master cylinder brace --man you can tell a differance. olddragger
01-30-2005, 04:55 PM
#43
Spin 9,
Uhhhh, welllll, lets put it like this. If you can see the mastercylinder MOVING as the brakes are being applied (hard) then it stands to reason that it needs a brace. Will it stop the car any faster? No. Will it make the brakes more responsive? Questionable. What it will do is make hard braking have a more consistant feel. That type of consistancy is important on the track as you are probaly already aware off. Same type of thinking I suppose as the braided brake/clutch lines'. I am far from being an expert and I dont have my strut bar YET(next week) but a track friend of mine and a very reputable rotor head/mechanic/track friend have both voiced that this was the most benefit they can feel from the bar.
What track are you running? Wish you could come to Road Atlanta with us. Last count we are going to have 10 rx8's there.
olddragger
Uhhhh, welllll, lets put it like this. If you can see the mastercylinder MOVING as the brakes are being applied (hard) then it stands to reason that it needs a brace. Will it stop the car any faster? No. Will it make the brakes more responsive? Questionable. What it will do is make hard braking have a more consistant feel. That type of consistancy is important on the track as you are probaly already aware off. Same type of thinking I suppose as the braided brake/clutch lines'. I am far from being an expert and I dont have my strut bar YET(next week) but a track friend of mine and a very reputable rotor head/mechanic/track friend have both voiced that this was the most benefit they can feel from the bar.
What track are you running? Wish you could come to Road Atlanta with us. Last count we are going to have 10 rx8's there.
olddragger
02-01-2005, 10:04 AM
#47
Momentum Keeps Me Going
Originally Posted by olddragger
Spin 9,
What track are you running? Wish you could come to Road Atlanta with us. Last count we are going to have 10 rx8's there.
olddragger
What track are you running? Wish you could come to Road Atlanta with us. Last count we are going to have 10 rx8's there.
olddragger
plus I watch all those crazy videos you guys post of the things you do while you're out there. Damn you, stop! :D more!PS After you get your brake brace installed, how about a 1st person review olddragger?
Last edited by Spin9k; 02-01-2005 at 10:07 AM.
02-11-2005, 09:34 AM
#50
Spin9K,
I will do that dude! Wish you could come on down to Road Atlanta with us! Charles Hill is driving down for the next event. A NASA 2 day event (= about 200 miles of track time!) for $299! And this time we have a professional video man that is going to do a better job than our previous videos. Date is March 19 and 20th. I just got the act prolite flywheel installed(reqs an auto rx 7 counterweight) and I can certainly write about that(all positive). The strut bar was delayed in shipping but should be here in the next 2 wks. I will report! I did drive a friends 8 that has the bar and on hard braking the petal feels more solid. Off course that is subjective and could be the result of a lot of differant things. Stay tuned.
take care man and keep talking to the wife! Its 52 degress today hehehe.
olddragger
I will do that dude! Wish you could come on down to Road Atlanta with us! Charles Hill is driving down for the next event. A NASA 2 day event (= about 200 miles of track time!) for $299! And this time we have a professional video man that is going to do a better job than our previous videos. Date is March 19 and 20th. I just got the act prolite flywheel installed(reqs an auto rx 7 counterweight) and I can certainly write about that(all positive). The strut bar was delayed in shipping but should be here in the next 2 wks. I will report! I did drive a friends 8 that has the bar and on hard braking the petal feels more solid. Off course that is subjective and could be the result of a lot of differant things. Stay tuned.
take care man and keep talking to the wife! Its 52 degress today hehehe.
olddragger