Rear strut bar - Installation questions
02-13-10, 09:26 AM
#51
In my first post, I made reference to sub-frame connectors and a brace for the rear of the front control arms. Here's one such brace: http://www.sfxperformance.com/parts/TABTUB032F.htm, although it's not the one I was thinking of - I know I've seen a brace that also combines with a subframe connector/cross brace, to thoroughly box the large transmission tunnel of these cars - the tunnel already being a strong point that becomes even more so when boxed and tied into the front and rear sub-frames, but I can't think of who made/makes it.
02-13-10, 10:43 AM
#53
Right near Malloy
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In my first post, I made reference to sub-frame connectors and a brace for the rear of the front control arms. Here's one such brace: http://www.sfxperformance.com/parts/TABTUB032F.htm, although it's not the one I was thinking of - I know I've seen a brace that also combines with a subframe connector/cross brace, to thoroughly box the large transmission tunnel of these cars - the tunnel already being a strong point that becomes even more so when boxed and tied into the front and rear sub-frames, but I can't think of who made/makes it.
Whatev... I just like ******* around.
02-13-10, 12:33 PM
#54
RX-spec7
In my first post, I made reference to sub-frame connectors and a brace for the rear of the front control arms. Here's one such brace: http://www.sfxperformance.com/parts/TABTUB032F.htm, although it's not the one I was thinking of - I know I've seen a brace that also combines with a subframe connector/cross brace, to thoroughly box the large transmission tunnel of these cars - the tunnel already being a strong point that becomes even more so when boxed and tied into the front and rear sub-frames, but I can't think of who made/makes it.
02-13-10, 12:51 PM
#55
try searching in icemark's posts, he had a writeup with part numbers of seam sealer he used. he had a vert daily driver and we all know how weak the frame torsion is on the vert models so he did his own R+D on stiffening the rigidity of the body and i have seen his car, there is almost no frame torsion when going into driveways on an angle lifting wheel+wheel.
02-13-10, 01:36 PM
#56
https://www.rx7club.com/2nd-gen-archive-72/my-2nd-gen-foamseal-project-743378/
02-14-10, 04:54 PM
#58
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Dammit, you made me do it. You made me reply! LoL!
Bigger diameter wheels allow them to clear bigger brakes and also run flatter tires. The trade-off made having heavier wheels increasing inertia there for increasing unsprung weight is made to improve steering precision and feel. BMW world racing cars of the 70s/80s had up to 21 inch wheels 'cause it looked cool???
Nowadays drilled rotors mainly are used for the same reason as you wanting 15 inch wheels on Porsches (reducing unsprung weight). Along with improved initial bite they have plenty of downsides which should be carefully thought truogh for each different application.
Now I and I think anyone who has ever looked at FC's agree with the weakspots the Pro's pointed out. I could also add tens more maybe even a hundred more before coming to the point of strutbars being needed. This does not however make them useless, not noticable or styling. (Not that you claimed all those things) It's just not as important as the very few points mentioned by the pro's.
You will just go with whatever someone says instead of looking at the car your self, looking for improvement and testing them out? In the end of the day a strutbar is a great and icrediably cheap upgrade that won't hurt you car you could do for 10 bucks...
Riz.
Mazda putting in strut bars is not a compelling argument one way or the other, since like any manufacturer, they will supply what customers expect. 19 or 20" rims on a Porsche (as with any car, I merely use Porsche as an example of a true performance-centric manufacturer that nevertheless succumbs to fashion dictates of customers) contribute only extra weight and inertial momentum. Cross-drilled brakes are a performance anachronism (still offered on Porsches, Vettes, and other high performance cars) whose value faded away in the 60's and 70's, when better pad materials removed the outgassing issue that could prevent good pad contact with rotors under repeated hard braking, while the cross-drilled rotors actually contribute to stress risers and rotor cracking under hard use. But again, many customers expect to have that visual bling, so manufacturers supply it.
Nowadays drilled rotors mainly are used for the same reason as you wanting 15 inch wheels on Porsches (reducing unsprung weight). Along with improved initial bite they have plenty of downsides which should be carefully thought truogh for each different application.
http://grassrootsmotorsports.com/articles/lucky-7/ - this article discusses prepping FC's for autocross and roadracing. It addresses the few weak points of the car, such as factory adjustable dampers - not that there are many still running these - insufficient camber adjustment in the front, and rear DTSS. The midsection chassis weakness is specifically mentioned. Nowhere are strut bars suggested as being useful. The article was written with input from successful RX-7 tuners and racers like Sylvain Tremblay of SpeedSource Racing - as opposed to the "ignorance of this thread", as you so kindly put it.
You will just go with whatever someone says instead of looking at the car your self, looking for improvement and testing them out? In the end of the day a strutbar is a great and icrediably cheap upgrade that won't hurt you car you could do for 10 bucks...
Riz.
02-15-10, 12:25 PM
#59
Dammit, you made me do it. You made me reply! LoL!
Bigger diameter wheels allow them to clear bigger brakes and also run flatter tires. The trade-off made having heavier wheels increasing inertia there for increasing unsprung weight is made to improve steering precision and feel. BMW world racing cars of the 70s/80s had up to 21 inch wheels 'cause it looked cool???
Nowadays drilled rotors mainly are used for the same reason as you wanting 15 inch wheels on Porsches (reducing unsprung weight). Along with improved initial bite they have plenty of downsides which should be carefully thought truogh for each different application.
Now I and I think anyone who has ever looked at FC's agree with the weakspots the Pro's pointed out. I could also add tens more maybe even a hundred more before coming to the point of strutbars being needed. This does not however make them useless, not noticable or styling. (Not that you claimed all those things) It's just not as important as the very few points mentioned by the pro's.
You will just go with whatever someone says instead of looking at the car your self, looking for improvement and testing them out? In the end of the day a strutbar is a great and icrediably cheap upgrade that won't hurt you car you could do for 10 bucks...
Riz.
Bigger diameter wheels allow them to clear bigger brakes and also run flatter tires. The trade-off made having heavier wheels increasing inertia there for increasing unsprung weight is made to improve steering precision and feel. BMW world racing cars of the 70s/80s had up to 21 inch wheels 'cause it looked cool???
Nowadays drilled rotors mainly are used for the same reason as you wanting 15 inch wheels on Porsches (reducing unsprung weight). Along with improved initial bite they have plenty of downsides which should be carefully thought truogh for each different application.
Now I and I think anyone who has ever looked at FC's agree with the weakspots the Pro's pointed out. I could also add tens more maybe even a hundred more before coming to the point of strutbars being needed. This does not however make them useless, not noticable or styling. (Not that you claimed all those things) It's just not as important as the very few points mentioned by the pro's.
You will just go with whatever someone says instead of looking at the car your self, looking for improvement and testing them out? In the end of the day a strutbar is a great and icrediably cheap upgrade that won't hurt you car you could do for 10 bucks...
Riz.
Moreover, the larger wheels actually demand larger brakes because of their negative impact on braking. Look at F1 - 13" rims. Champ car: 15", even heavy NASCAR stockers - 15" (although NASCAR specs are anachronistic generally, so hard to read a lot into that). Low profile tires do not requires large diameter rims, btw - I assume that's what you meant by "flatter tires".
I still stand by my point - reinforcing the already strong front and rear structures of an FC with strut bars is largely pointless, at least until the mid section chassis is reinforced. Otherwise, you aren't preventing chassis flex/deflection from suspension inputs, you're just directing more of that energy into the portion of the chassis that is already most prone to torsional flex - the cabin. PvillKnight's bar pic above looks to be a well done rear bar design - but worth noting is that it's in a stripped, caged chassis.
Can you show me any testing that shows strut bars improve the FC chassis, at least with spring rates and grip levels typical of street or autocross cars? I'd be interested to see if anyone has (although if the Efini IV bars were added for a primary reason other than style, I would think Mazda would have such data), but I'm very much in doubt such exists, having been a RX-7 owner and competitor for 12 years, and a fan longer, and I've yet to see anyone show benefits without adding the lower chassis brace and mid-section reinforcement first. Saying it "feels" better is, as was pointed out by another poster, often a case of placebo effect - having spent time and money, people want to be able to say it was worthwhile.
The FC is not a willowy economy car or sedan, or sport-y car derived from such - it was purpose designed to be a sports car with exceptional chassis rigidity - part of why Mazda's engineers blew through their weight goals for the car. One was achieved at the expense of the other.
02-15-10, 03:02 PM
#61
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You'd be hard-pressed to find factory, or even aftermarket "big brake" kits that need wheels larger than 18", and few that demand larger than 17" wheels - but the large wheels do hurt both acceleration and braking thanks to increased inertial momentum - think adding 4 heavier flywheels - racers certainly don't use big wheels, they typically look for as small a rim diameter as possible (though of course width is desired) - making 17s and 18s the big rims for road racers/endurance racers. For endurance, larger rims (17s and 18s) and tires provide advantage mainly in the form of more tire surface area, which is useful both for tire longevity, and more so for increased area to absorb and then re-radiate heat.
Moreover, the larger wheels actually demand larger brakes because of their negative impact on braking. Look at F1 - 13" rims. Champ car: 15", even heavy NASCAR stockers - 15" (although NASCAR specs are anachronistic generally, so hard to read a lot into that). Low profile tires do not requires large diameter rims, btw - I assume that's what you meant by "flatter tires".
In my country profile (profiel) means the thread which is only a few mm deep. So sorry yes I meant low profile tires. Low profile tires in combination with small diameter rims obviusly results in smaller overall diameter. This is (not always) wanted.
I'll just leave these pictures of classic race cars with big wheels (up to 21 inches) from way before it was fashionable to have big wheels... Rice?
I'm not cheering for huge heavy wheels, by no means. I would never run bigger than 18 on my FC, probably keep with 17 inches, but I just don't like the fact how black/white you are. You think the people who developed the cars above were stupid, didn't know their profession? No, there is different products needed for different cars in different situation, not every car is the same, and even if they are, not very car is used the same way in teh same setting
Can you show me any testing that shows strut bars improve the FC chassis, at least with spring rates and grip levels typical of street or autocross cars? I'd be interested to see if anyone has (although if the Efini IV bars were added for a primary reason other than style, I would think Mazda would have such data), but I'm very much in doubt such exists, having been a RX-7 owner and competitor for 12 years, and a fan longer, and I've yet to see anyone show benefits without adding the lower chassis brace and mid-section reinforcement first. Saying it "feels" better is, as was pointed out by another poster, often a case of placebo effect - having spent time and money, people want to be able to say it was worthwhile.
The FC is not a willowy economy car or sedan, or sport-y car derived from such - it was purpose designed to be a sports car with exceptional chassis rigidity - part of why Mazda's engineers blew through their weight goals for the car. One was achieved at the expense of the other.
About those AutoExe parts. If you look under your car, and you can imagine a bit and got basic understanding of the forces put of the car you can make those parts yourself for less. The perfect fit is convient though if you have the cash for AutoExe.
Riz.
03-01-10, 11:33 PM
#63
Just received my $66 with shipping 3 piece eBay strut brace as seen on page 2, it's the same as the $170 one!!! The allen bolts they give you for the speaker mounts are a little too short, thus Ace hardware for me in the morning then I'll post the pictures. Another great eBay buy!!!!
03-05-10, 01:08 AM
#66
No doubt! It looks like a strong design and crazy easy to install. Anyone know if the front bar by the same people fits the turbo models with the top mount?
http://cgi.ebay.com/ebaymotors/86-87...item5886274e53
http://cgi.ebay.com/ebaymotors/86-87...item5886274e53
03-05-10, 01:35 AM
#67
The rear one in the pic above is either a TC Sportsline or knock off of one.
Post #8: https://www.rx7club.com/showthread.p...urbo+strut+bar
[QUOTE=SpeedOfLife;9847190]No doubt! It looks like a strong design and crazy easy to install. Anyone know if the front bar by the same people fits the turbo models with the top mount?
Post #8: https://www.rx7club.com/showthread.p...urbo+strut+bar
[QUOTE=SpeedOfLife;9847190]No doubt! It looks like a strong design and crazy easy to install. Anyone know if the front bar by the same people fits the turbo models with the top mount?
03-05-10, 01:50 AM
#69
The one you asked about is a knock off of the one I linked but they are one in the same design, I just didn't have a pic of the knock off so I provided you with a pic of the "non-knock off." I'm sure the knock off is probably cheaper in case you want to go with the knock off.
03-05-10, 10:07 AM
#70
In their separate listings they include in the description:
"BRAND NEW ALUMINUM STRUT TOWER BAR BY TC SPORTLINE. THE BAR IS BUILD FOR EACH SPECIFIC VEHICLE FEATURING MULTI-CHAMBER CONSTRUCTION WITH NON PIVOTAL ENDS FOR STRENGTH AND STABILITY. THIS STRUT TOWER BAR WILL IMPROVE YOUR VEHICLE'S HANDLING, CORNERING ABILITY, AND STEERING RESPONSE."
I know the images don't show the label though, which is strange. Personally I wouldn't mind if they aren't TCS because they look solid to me, but it would be kinda stupid for them to say that's what they are if they're not.
Front:
http://cgi.ebay.com/ebaymotors/FRONT...item27afa4f992
Rear:
http://cgi.ebay.com/ebaymotors/ws/eB...=STRK:MEWAX:IT
"BRAND NEW ALUMINUM STRUT TOWER BAR BY TC SPORTLINE. THE BAR IS BUILD FOR EACH SPECIFIC VEHICLE FEATURING MULTI-CHAMBER CONSTRUCTION WITH NON PIVOTAL ENDS FOR STRENGTH AND STABILITY. THIS STRUT TOWER BAR WILL IMPROVE YOUR VEHICLE'S HANDLING, CORNERING ABILITY, AND STEERING RESPONSE."
I know the images don't show the label though, which is strange. Personally I wouldn't mind if they aren't TCS because they look solid to me, but it would be kinda stupid for them to say that's what they are if they're not.
Front:
http://cgi.ebay.com/ebaymotors/FRONT...item27afa4f992
Rear:
http://cgi.ebay.com/ebaymotors/ws/eB...=STRK:MEWAX:IT
03-05-10, 05:07 PM
#73
http://www.srbpower.com/cusco/strut-bar?Make=MAZDA
Rear OS Bar and 3-Point Lower Bars
http://www.tanabe-usa.com/underbrace.asp
http://www.fujitaengineeringusa.com/fc3s3.html
Last item on that page
http://www.imageinmotion.com/cuscopillarsidebars.php
The old H-M0201 bar from Mazdatrix, discontinued now for the Front Strut Towers, bolts to the towers, the firewall and serves as an engine torque brace.
Those are the only things I've heard of that will stiffen the chassis short of the cage.
Rear OS Bar and 3-Point Lower Bars
http://www.tanabe-usa.com/underbrace.asp
http://www.fujitaengineeringusa.com/fc3s3.html
Last item on that page
http://www.imageinmotion.com/cuscopillarsidebars.php
The old H-M0201 bar from Mazdatrix, discontinued now for the Front Strut Towers, bolts to the towers, the firewall and serves as an engine torque brace.
Those are the only things I've heard of that will stiffen the chassis short of the cage.
