Mobius's Build - Brotrex and Bromex galore! - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Build Threads Building a motor? Post the progress here.

Closed Thread
 
 
 
LinkBack Thread Tools Search this Thread
Old 02-18-2012, 06:34 PM   #21
Elite Member
Thread Starter
iTrader: (2)
 
Mobius's Avatar
 
Join Date: May 2008
Location: Portland, Oregon
Posts: 3,176
Total Cats: 261
Default

Dyno tuning will be delayed, unfortunately. I'm unable to get the hose that died in my driveway yesterday fixed in time. The "equivalent" replacement that I scrounged after 2 hours of searching yesterday is ... not equivalent, and won't go over the hose barb. So I bit it and ordered two from Finishline. The hose that died is bp6d-15-261, goes from the water neck down to the mixing manifold.
Mobius is offline  
Old 02-18-2012, 10:40 PM   #22
Cpt. Slow
iTrader: (25)
 
curly's Avatar
 
Join Date: Oct 2005
Location: Oregon City, OR
Posts: 12,105
Total Cats: 518
Default

Where are you dyno'ing? We'll have to have a dyno day once both are cars are done, I'm sure some of the CR peeps would enjoy knowing what their h/e/i has netted them.
curly is offline  
Old 02-18-2012, 11:07 PM   #23
Elite Member
Thread Starter
iTrader: (2)
 
Mobius's Avatar
 
Join Date: May 2008
Location: Portland, Oregon
Posts: 3,176
Total Cats: 261
Default

PDX Tuning in NorthWest. They haven't done an xede in a while, but at least they've done them before. Not that it's terribly complicated, but I have discovered that I really do not like trying to tune on the street. Part of that is due to the only laptop I have available being a big honkin' 17" Dell XPS with a battery life of about 75 minutes. That would still be doable, but even in 3rd a pull to 7k puts me at about 70 and I haven't found a nearby spot that's calm enough and safe enough (both in terms of other traffic, and citation risk) for that. Dyno is the way to go. Ms Mobius even agrees.
Mobius is offline  
Old 03-11-2012, 08:09 PM   #24
Elite Member
Thread Starter
iTrader: (2)
 
Mobius's Avatar
 
Join Date: May 2008
Location: Portland, Oregon
Posts: 3,176
Total Cats: 261
Default

Shock Tower Brace modifications.

My intake piping interferes with the FSB. I have finally gotten around to modifying it to fit the intake piping.

First I eyeballed it, then cut out what looked to be enough to clear the piping:



Then I put it on to test fit the clearance:




Then I made cardboard templates for the structural pieces to replace what I cut out. Cardboard was cut and fitted while the piece was on the car, but didn't get shots of that:



Then I cut the steel using the cardboard templates from 3"x1/8" steel from Ace Hardware Home Racing, and test fit on the car:




Then I welded it with my neighbor's Harbor Freight special Mig Welder and auto-darkening hood, grinded & sanded it, and primered & painted it.



[IMG][/IMG]



There are many who say the FSB isn't needed on the Miata. While it certainly isn't necessary, I could tell a difference when I took the brace off. The car feels more solid up front even under normal highway driving conditions with it on. Tying the front suspension together across the top, and thereby closing and completing a structural box around them, can't be a bad thing.
Attached Thumbnails
Mobius's Build - Brotrex and Bromex galore!-stb_001-small-.jpg   Mobius's Build - Brotrex and Bromex galore!-stb002-small-.jpg   Mobius's Build - Brotrex and Bromex galore!-stb004-small-.jpg   Mobius's Build - Brotrex and Bromex galore!-stb005-small-.jpg   Mobius's Build - Brotrex and Bromex galore!-stb006-small-.jpg  

Mobius's Build - Brotrex and Bromex galore!-stb007-small-.jpg   Mobius's Build - Brotrex and Bromex galore!-stb008-small-.jpg   Mobius's Build - Brotrex and Bromex galore!-stb009-small-.jpg   Mobius's Build - Brotrex and Bromex galore!-stb010-small-.jpg   Mobius's Build - Brotrex and Bromex galore!-stb011-small-.jpg  

Mobius's Build - Brotrex and Bromex galore!-stb012-small-.jpg  
Mobius is offline  
Old 03-11-2012, 09:06 PM   #25
Elite Member
iTrader: (13)
 
Join Date: Dec 2009
Location: Fraser Valley, British Columbia
Posts: 2,502
Total Cats: 13
Default

Because of the design of the front end of the Miata, theoretically you shouldn't be able to tell any difference on or off. Unless it's a 3 point tying in the firewall. I vote placebo effect.
falcon is offline  
Old 03-12-2012, 08:14 AM   #26
Junior Member
iTrader: (3)
 
Join Date: Oct 2011
Location: Naperville
Posts: 369
Total Cats: 3
Default

Quote:
Originally Posted by falcon View Post
Because of the design of the front end of the Miata, theoretically you shouldn't be able to tell any difference on or off. Unless it's a 3 point tying in the firewall. I vote placebo effect.
How did you come to that conclusion? Has testing been done?
tomiboy is offline  
Old 03-12-2012, 08:45 AM   #27
Elite Member
iTrader: (13)
 
Join Date: Dec 2009
Location: Fraser Valley, British Columbia
Posts: 2,502
Total Cats: 13
Default

If I had done testing, I wouldn't have said theoretically.
falcon is offline  
Old 03-12-2012, 02:49 PM   #28
Junior Member
iTrader: (3)
 
Join Date: Oct 2011
Location: Naperville
Posts: 369
Total Cats: 3
Default

Explain the theory then. Inquiring minds want to know. I have a factory strut brace and if it doesn't do anything of value then why carry around the extra weight? Theoretically I could remove it.
tomiboy is offline  
Old 03-13-2012, 10:28 AM   #29
Elite Member
iTrader: (13)
 
Join Date: Dec 2009
Location: Fraser Valley, British Columbia
Posts: 2,502
Total Cats: 13
Default

Because of the front end suspension design and geometry, the Miata as well as other cars with a-arm suspension (like the RX7) do not benefit from a tower brace. The forces put on the shock towers are vertical whereas in a McPherson strut system, where a tower brace works to help battle any alignment deflection during hard cornering, the forces are much more side to side. Even RacingBeat wrote on their site that they have found no measurable difference running with or without one, hence why they don't make one.

http://www.racingbeat.com/mazda/perf...wer-brace.html

Quote:
Why doesn't Racing Beat offer a "strut" tower brace?

Well, since the Miata is not equipped with a "strut" type suspension, we have never been compelled to offer a "strut" brace! Unlike some automotive applications that utilized McPherson strut suspension designs, the Miata was designed with a more performance-oriented front and rear double wishbone suspension.

On many early RX-7 applications, which utilized the McPherson strut style suspension, the tops of the strut "towers" were a more integral component of the suspension and bore both vertical and horizontal loads of the suspension. Many of these early cars featured upper strut towers that were inboard of the inner body panels and suffered measurable flexing while under load. For these applications, a brace between the tops of these strut towers provided significant structural rigidity. If room allowed, further bracing of the towers against and the firewall (a triangulated brace) further added to this rigidity.

On the Miata application, the tops of shock towers are subjected to primarily vertical loads from the upward movement of the springs and shocks. Adding a brace between the tops of these towers has not shown any measurable handling benefit during our testing.
Again on Wiki... only mentions of McPherson strut systems in relation to tower braces.

Quote:
A strut bar, strut brace, or strut tower brace (STB) is a mostly aftermarket car suspension accessory usually used in conjunction with MacPherson struts on monocoque or unibody chassis to provide extra stiffness between the strut towers.

With a MacPherson strut suspension system where the spring and shock absorber are combined in the one suspension unit, the entire vertical suspension load is transmitted to the top of the vehicle's strut tower, unlike a double wishbone suspension where the spring and shock absorber may share the load separately. In general terms, a strut tower in a monocoque chassis is a reinforced portion of the inner wheel well and is not necessarily directly connected to the main chassis rails. For this reason there is inherent flex within the strut towers relative to the chassis rails.

A strut bar is designed to reduce this strut tower flex by tying two parallel strut towers together. This transmits the load of each strut tower during cornering which ties the two towers together and reduces chassis flex. To accomplish this effectively (especially on MacPherson strut suspensions), the bar must be rigid throughout its length, and also attached to the firewall.[citation needed]
falcon is offline  
Old 03-13-2012, 12:32 PM   #30
Junior Member
iTrader: (3)
 
Join Date: Oct 2011
Location: Naperville
Posts: 369
Total Cats: 3
Default

Want to but an STB?

Seriously...thanks for the links and explanation!
tomiboy is offline  
Old 03-13-2012, 12:52 PM   #31
Elite Member
iTrader: (13)
 
Join Date: Dec 2009
Location: Fraser Valley, British Columbia
Posts: 2,502
Total Cats: 13
Default

No thanks :P... All it really does is add extra un needed weight and gets in the way when you're working on the car. Go to any SCCA National Tour and check out the top CSP cars. None of them run STB's.
falcon is offline  
Old 03-14-2012, 07:33 PM   #32
I'm Miserable!
 
Join Date: Apr 2010
Location: Alberta, Canada
Posts: 135
Total Cats: -23
Default

That is a very one sided view. It would be nice if any of it took into account that the miata is a convertible and loses a considerable amount of chassis rigidity because of it. There's a lot more to overall chassis rigidity than a "strut tower brace". The upper shock mount brace was part of a comprehensive chassis upgrade that included a brace connecting the lower rear front a-arm mounts, a mid chassis cross member and 2 rear lower a-arm braces. All told I doubt there's 40 lbs of added weight but the added chassis rigidity is well worth it.

I highly doubt that Mazda would have bothered with the chassis braces it put into the '01 up Miatas if there wasn't any benefit. The Miata had already been in production for many years and was selling well so it certainly wasn't merely a marketing ploy. Why would a manufacturer add to production costs with no apparent reason, personally I doubt they would.

Just my 02 cents

JimJ
jimj64 is offline  
Old 03-14-2012, 09:53 PM   #33
Cpt. Slow
iTrader: (25)
 
curly's Avatar
 
Join Date: Oct 2005
Location: Oregon City, OR
Posts: 12,105
Total Cats: 518
Default

It depends on why the car was selling. People may have wanted a car that felt more substantial, didn't have as many little creaks and wobbles. Possibly even safer. They're not necessarily making the car faster, which is what we're debating. Take those 40lbs of braces out and it might not feel as stiff, but you might see a faster time around an autox course or track.

More to the point, the STB was supposedly made to keep strut towers from flexing, because when they do the alignment is thrown off, which isn't a problem with our double a-arm setup. Same reason we can't use camber plates. Therefore, although you might feel like your car is stiffer with a STB bolted on, it won't actually be helping make the suspension work any better, yet will be adding weight.

That's not to say you won't like the stiffness added with one, which is another topic altogether.

P.S. I'm not taking either side of the argument, so don't argue with me, just clarifying Falcon's point.
curly is offline  
Old 03-15-2012, 07:55 PM   #34
I'm Miserable!
 
Join Date: Apr 2010
Location: Alberta, Canada
Posts: 135
Total Cats: -23
Default

I never said the shock tower brace had anything to do with suspension flex, I said it was part of a chassis stiffening package.

I don't believe Mazda calls it a "strut tower brace", why would they? It's a shock tower brace, as has been pointed out the miata does not have McPherson struts, so the comments about "strut tower braces" are kinda irrelevant. The discussion should be about whether or not the brace contributes to chassis stiffness not if it reduces front suspension flex. I'm sure the Mazda engineers know the difference between McPherson struts and dual a-arms, after all Mazda has used both and chose to put dual a-arms at all 4 four corners for a reason.

Falcons observations and comments are based on Mazda engineers being to stupid to know what kind of suspension they put on their own car, I highly doubt that's the case.
jimj64 is offline  
Old 03-15-2012, 08:10 PM   #35
Elite Member
iTrader: (13)
 
Join Date: Dec 2009
Location: Fraser Valley, British Columbia
Posts: 2,502
Total Cats: 13
Default

Ever hear of a "selling feature?" .... "ohhh, that one has a tower brace... I want that one."

Ask any of the real racers here on their opinion. I am just a mere mortal compared to Sav and Emilio, but IIRC I have read Emilios opinion on the subject before and he dosen't run one.

Curly.., when I originally posted I mentioned that a 3 point brace would be usefull. Based on what I can see as to how the front end is designed, running just a shock tower brace just boxes in that area but dosen't triangulate it.


I am drunk.
falcon is offline  
Old 03-15-2012, 08:41 PM   #36
Cpt. Slow
iTrader: (25)
 
curly's Avatar
 
Join Date: Oct 2005
Location: Oregon City, OR
Posts: 12,105
Total Cats: 518
Default

Yea, and if you read FM's description on their own site, they say you're bolting it to a flimsy firewall, which makes sense to me, but I don't have any experience with one.

Jim, you're putting words in my mouth, please don't do that. I never said Mazda didn't know what suspension they put in the car, it's just that with the majority of STBs talked about, looked at, and referred to on the internet, the "S" stands for Strut. And like I said, since it's not helping keep our alignment aligned, it's only for chassis stiffness, which doesn't count for anything on track but driver's comfort. AKA: It might not be beneficial for OP's car, since he's building a bit of a track ****. Although, he has many other ways to save weight than on just the STB.
curly is offline  
Old 03-16-2012, 12:02 AM   #37
I'm Miserable!
 
Join Date: Apr 2010
Location: Alberta, Canada
Posts: 135
Total Cats: -23
Default

I wasn't putting words in your mouth Curly, I was referring to Falcons comments. He keeps referring to the miatas "strut tower brace" and talking about how strut tower braces are intended to reduce flex in McPherson strut front ends, and he is correct, that's what "strut tower braces" are for.

Clearly the miata does not have McPherson struts and therefore does not have a strut tower brace. The '01+ Miatas with the sport suspension package have a front shock tower brace that are part of a chassis stiffening package that is intanded to improve handling/steering characteristics by strengthening/stiffening the chassis.

Honestly I didn't disagree with anything you said.

Quote:
Originally Posted by curly View Post
Yea, and if you read FM's description on their own site, they say you're bolting it to a flimsy firewall, which makes sense to me, but I don't have any experience with one.

Jim, you're putting words in my mouth, please don't do that. I never said Mazda didn't know what suspension they put in the car, it's just that with the majority of STBs talked about, looked at, and referred to on the internet, the "S" stands for Strut. And like I said, since it's not helping keep our alignment aligned, it's only for chassis stiffness, which doesn't count for anything on track but driver's comfort. AKA: It might not be beneficial for OP's car, since he's building a bit of a track ****. Although, he has many other ways to save weight than on just the STB.
jimj64 is offline  
Old 03-20-2012, 06:55 PM   #38
Elite Member
Thread Starter
iTrader: (2)
 
Mobius's Avatar
 
Join Date: May 2008
Location: Portland, Oregon
Posts: 3,176
Total Cats: 261
Default

Car is finally running properly. I had a vacuum leak due to the vacuum hose between the intake manifold (the "dynamic chamber" in service manual parlance) and the throttle body being disconnected. That hose has a curve in it, and was right in front of the barb, appearing to be connected at casual glance when in fact it was not.

Second problem was a faulty connection to injector #2, which was causing intermittent misfires and hesitation at about 4500rpm until it quit entirely. I swapped injector #1 with injector #2 and put dielectric grease on all of them, and everything runs well now.

Regarding the shock bar: I think I can tell a difference in steering feel with the bar on vs bar off, and in my view it just makes sense to tie the suspension mountpoints together across the engine bay to minimize lateral flex and let the suspension do its job. The factory bar is beefy and mounts solidly. I will agree with anyone who thinks that the bars with hinges in them are a waste of money, but the factory bar mounts solidly into a trapezoidal structure that will resist racking forces.


Next up now that the car is finally running right is the new dyno day, to see where we're at unrestricted. Gopro video from the rollbar mount will be provided.

Fodder from FM's website:
Cars with strut suspensions rely on the top of the strut towers to maintain their suspension geometry - and inconveniently, there`s usually an engine between them in the front. So strut tower braces are very popular to improve the handling on those cars.

But a Miata has a double wishbone front suspension. The top of the shock towers is mostly taking vertical loads. But there`s still a big hole in the middle of the engine bay, and that means the structure of the car suffers in this area. Joining the shock towers together with a well-designed brace will improve steering feel and cut down on cowl shake when you hit a bump.
Mobius is offline  
Old 04-07-2012, 03:36 PM   #39
Destroyer of Inconel
iTrader: (37)
 
EO2K's Avatar
 
Join Date: Apr 2010
Location: In ur driveway, abusin' ur WPA
Posts: 9,642
Total Cats: 954
Default

Just took my first stab at intercooler today following your build. I got the nose and the ductwork off the front of the car, I lol'd, then reassembled. There are some differences in the 99/00 AC system I need to figure out how to work around.

I noticed you did this:
Quote:
Originally Posted by Mobius View Post
* Power steering hard lines: This was somewhat of a PITA. I ended up only keeping the loop of hard line that mounts under the hood latch. I eliminated the middle part and replaced with hose to clear the intercooler. I tried bending them but was dissatisfied with the results. For anyone else doing this, just go ahead and cut it and re-connect with hose rather than trying to bend them.
What type or rating of hose did you use for the PS reroute? Heads up on size would also be awesomes.

Thanks again for posting all of this stuff, with pics. It's really helped me along.
EO2K is offline  
Old 04-08-2012, 12:11 AM   #40
Elite Member
Thread Starter
iTrader: (2)
 
Mobius's Avatar
 
Join Date: May 2008
Location: Portland, Oregon
Posts: 3,176
Total Cats: 261
Default

You need the uber special-order hose known as, wait for it: "power steering hose". Can't recall the ID off the top of my head but any parts store should have what you need. The PS cooler is on the low-pressure side of the loop.
Mobius is offline  
 
 
Closed Thread

Related Topics
Thread Thread Starter Forum Replies Last Post
LucaCarMods's Boosted Dutch Miata Build! LucaCarMods Build Threads 11 02-14-2016 07:13 AM
WTB MP62 (Hotside) (NB2) Rick02R WTB 3 01-03-2016 08:18 PM
Is my swirl pot design okay? FrankB Race Prep 10 10-02-2015 10:00 PM
Bad head gasket or ? shooterschmidty Engine Performance 8 09-30-2015 11:28 PM
Image resizer concealer404 Front Desk 3 09-29-2015 01:41 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 04:03 AM.