Paulgt2164's Summer Project

[ZfrkS62]

Is a sugar pill that might make your girlfriend more comfortable when you drive down the street worth 80 dollars? That is the question you have to ask yourself.

i've been going on the premise that this whil argument pertains to the track. If your comments about them were in refrence to street application than i agree, x-drilled rotors are useless.

Properly designed, drilled discs tend to operate cooler than non-drilled ventilated discs of the same design due the higher flow rates through the vents from the supplemental inlets and increased surface area in the hole.

Now i'm not sure, but it sounds like this statement at the end of one of your copy and paste posts on page 2 of this debate, just worked against you. I am assuming of course stop tech is refering to the track on this as stop and go driving on the street negates all of this.

so before i royally stick my foot in my mouth, can you please clarify which application you are basing this on? street or track?

[graywolf624]

As I stated above.. the key thing your looking for from a rigidity stand point is from a torsion stand point.. That is you want the front inputs to move in concert with the rear pickups(hence sfcs and other types of chasis stiffening components).
The differences here are two fold. a) you dont stiffen something up by tieing it to something that moves.. Rather to stiffen something up you tie it to something that is already rigid.. say a frame rail.
Furtheremore, the direction of torsion on a car acts around a centerline.. the roll center.. that is an imaginary line through the middle of the car as you look straight at it.

Here is an attempt at a ascii graph since the schematics I had on this stuff as drawn by these guys and myself are long since gone and Im a little to busy right at the mometn to draw you a paint picture and then find a host.

car head on view..
.=space

---------
|....x....|
---------
where x is the center of rotation.. a line that runs through the entire length of the car as determined by roll center.. aka.. take the crossing of lines from instant center to lower of your tire on each side and where they cross is your roll center for the front.. for the rear you do the same thing.. both dependent on the control arms or strut depending on which application thereof (sai)..


Now what this means from a top down approach

top of car view
x---------x
|...........|
|---------|
|...........|
+--------+

is that the torsion forces are acting at each end.. where x represnts a force down.. and + represnts a force up or movement up towards you depending on if your getting a jacking effect. The middle line is where the center of rotation is.. obviously the center of a symetrical car. it moves under movement.. but still stays on same orientation..
Now.. a strut bar (2 piece only).. is tieing two piece.. struts..

top of car view
x---------x
| s.........|
|-t-------|
| b........|
+--------+


together.
now these struts.. a) are both moving minimally.. linearly.. aka left to right..
(we are ignoring up and down right now.. which by the way.. is in the neighborhood of 10000 lbs as opposed to the general moment of force on struts laterally being the equivelent of maybe 200.. ball park estimates from an example given by a friend) Now what we notice is that the struts can obviously take 10000 lbs vertically so why is 200 going to be a problem?

b) the stb is controlling forces moving left to right.. not from the rear pickups to the fronts.. cause its not triangulated..

aka..
top of car view
x---------x
| s..........|
|-t--t-----|
| b.........|
+---------+

where t represents a 3 point brace(depending on what its tied too.. take the fbodies.. possibly poorly designed).. but.. as you can see.. it helps tie the front pickups.. or wheels.. to the rear ones. Which is what we wish to achieve with added rigidity.

Moreover...On the issue of camber:
Remember.. tieing together strut towers together doesnt decrease camber loss.. but rather simply splits it between the inside and outside wheel. While the inside wheel of the turn is clearly less important then the outside.. It still decreases overall grip.

[graywolf624]

i've been going on the premise that this whil argument pertains to the track. If your comments about them were in refrence to street application than i agree, x-drilled rotors are useless.

i think you just misunderstood me.. x-drill rotors are useless on the track.. the street reference was to say that that is the only place you might notice a difference in terms of initial bite(aka degausing pads) and initial wet weather braking (porsche even says as much.. remember the larger the surface area the less grip in the rain since it takes more to sweep the water off the rotor). I stand by the statement that you cant show me a single pro race car in the modern era with cross drilled iron rotors. (go karts and formula sae dont count.. neither do motorcycles.. as all 3 can fall under the so light you can throw something 6 x to big on it and get away with it). The same thing falls into place for the stb.. on the street you will find better nvh qualities (ignoring the placebo effect). On the track, nvh should be the least priority.

Now i'm not sure, but it sounds like this statement at the end of one of your copy and paste posts on page 2 of this debate, just worked against you. I am assuming of course stop tech is refering to the track on this as stop and go driving on the street negates all of this. so before i royally stick my foot in my mouth, can you please clarify which application you are basing this on? street or track?

its about the track.. and thats not what stop tech is going for. If you check out there website.. youll find an article by Carrol smith, the man I was telling you that I feel is the greatest race engineer of the 90s and wrote the commonly agreed upon two best books on racing and race engineering.. tune to win and drive to win.

Basically the idea is that the cross drilled do in fact cool faster.. air flows through alla a centrifigual pump.. If I recall.. in through the holes.. then out through the veins(only works for veined rotors). So they cool more.. but heat absorbtion.. works faster then heat shedding to air.. aka the heat is stored in the metal quicker then it ever can be made to leave to the air. By decreasing metal your thus decreasing the heat sinc capabilities. Aka theres less place for the heat to go. As such on a race car.. besides the inherent problems with cracking due to interuption of the crystaline latice structure of iron rotors that is unavoidable and heat stress risers where the temperature is not uniform across the rotor.. theres now the issue that at any moment the brakes can take less heat in a specific moment. Thats a big deal with road racing cars.. and the exact reason (other then the inherent danger due to cracking) that they arent used in racing anymore. Well that and it actually causes the pads to heat up quicker and also with heat risers.. This is also why they call it an aestethetic item.

Now a word of caution.. I do not comment nor intend to comment on the use of ceramic rotors. The specific thermal capacity of this substance is higher then that of iron. I do not know the numbers, nor have I ever had the pleasure of driving a car so equipped.. so don't ask or post pictures of one.. cause I cant answer questions with regards to their setup.

[graywolf624]

For more information on these subjects and more.. in addition to the above threads I already posted..
I would suggest stop techs knowledge base on their website (http://www.stoptech.com/technical/) , corner-carvers (we may have attitudes, but its hard to argue we dont know are shit. Do a search for altima cross drilled), tune to win by Caroll Smith, and The june july and august editions of mustang enthusiast(a set of articles on race geometry by the guy I quoted earlier thats a friend of mine). Other resources can be found on the net.. including, but not limited to:

analysis active suspension(I havent read this one actually)
http://www.tonyfoale.com/Articles/carstuff/spring.htm

analysis ta suspension
http://members.aol.com/sccacuda/cars/1SmthTa.html

analysis gpl formula cars
http://eaglewoman.racesimcentral.com...amics-susp.htm

Please read the stuff to have a complete understanding of the concepts thereof.. admitedly Im not the greatest at explaning concepts without being wordy and boring people. I found this out when my papers were ridiculed by my friends for being too dry. Apparently I put some people to sleep.

[coombsie66]

^^ Thankyou for the obvious time and effort put into your posts in reply to mine. I believe i now see what you mean, and i totally agree that tieing the 2 front struts together merely shares the dynamic camer change between the inside and outside tyre.
I havent read the articles above yet, but i shall try when im a little less tired .
Cheers

[PaulGT2164]

Update!

The epic journey was a success with no hiccups whatsoever

we drove over 2000 miles in 3 days without a single problem in the miata

we went from Phoenix AZ -> Grand Junction CO (for dyno tuning) -> Kansas City, MO, to St. Louis, MO, then home to Murray, KY

30 hours in a miata is torture, but the scenery was amazing, i will post pics on the previous mentioned website some time this week

the car put down about 260WHP and 257 FT/Lbs at 5500 feet elevation on 91 octane gas, so the initial estimates of 300 hp are very close due to the home of the car being close to sea level, and on better gas, we still have some final tuning to do, but the car is very fast.

Bill Cardell and the Flying Miata Crew should win medals for their support, if you are a miata owner BUY parts from them, they are awesome
the Rototest dyno they had was being fussy, so Bill arranged some dyno time at the machine shop that done all the headwork on the motor, they had just got the dyno and it was still kinda buggy, but we eventually got the car basically tuned and dyno'ed . we had to retune the boost/wastegate setting here in ky cause we are 4000 feet lower in elevation. The Flyin Miata crew (www.flyinmiata.com) were awesome, Long live turbodog

the odd points on the trip were, we seen a plane crash in utah (personal small aircraft) seen the presidental motorcade in st louis, and anough small animals were ran over to make a nice buffet, luckily none big enough to cause any damage. i seen a ferrari 575 in scottsdale az (i have a pic of the behind) along with two 355s, and two maserati spyders! the salt flats in utah were cool, but the mountain roads in colorado were breathtaking (ill post pics sometime)

i will be moving to the mesa az area outside of phoenix friday, so if theres any JB worlders in the area let me know!

Also, Valentine One radar detectors are the best, hands down, it saved our butts about 60 times lol

[homemade wrx]

that is a pretty nice/will be nicer miata there. The craziest miatas I've heard/read about either have to be the V8 miatas (with no handling) or a turbocharged 400 whp miata. It has a Ford 9 inch rear end as well!!
take it easy, Micah
and good luck

[PaulGT2164]

yeah the next upgrades being considered to the car is a bigger turbo and different rear end gears/diff
we are gonna swap the 3.9 rear gear out for a 3.6 and possibly order a "guru" differential unit which is the best for the miata then that should make the drivetrain alot stronger cause the stock differential was the only real weak point