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-   -   Home Alignments (https://www.miataturbo.net/general-miata-chat-9/home-alignments-14318/)

Braineack 11-27-2007 02:43 PM

Home Alignments
 
Anyone doing them? if so what tool are you using for camber?

Toe should be simple enough with string and a ruler.

cjernigan 11-27-2007 02:54 PM

I read up on that a while back. Lots of people were recommending a digital bubble level at sears for like $30. Give you a degree readout to the tenth or hundredth of a degree.

Braineack 11-27-2007 02:56 PM

I assume since we usually want caster maxed, that we really don't need a gauge, or do you just rotate the level 90°?

levnubhin 11-27-2007 02:57 PM

soflarick does it pm him.
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cjernigan 11-27-2007 03:00 PM

Not that i like to link to .net but here you go.
http://forum.miata.net/vb/showthread.php?t=257646

SamS 11-27-2007 03:26 PM

My dad and his other old engineer buddy decided they could align my miata last winter. After using his buddy's 40-year old jc whitney tools and drawing some chalk marks on the floor, my steering wheel was turned about 30 degrees from center while driving straight, and the entire car would go down the street at an angle on snowy roads.

s4miata 11-27-2007 03:30 PM

didnt 949 racing sell align tools for the miata?

paul 11-27-2007 03:52 PM


Originally Posted by SamS (Post 178521)
My dad and his other old engineer buddy decided they could align my miata last winter. After using his buddy's 40-year old jc whitney tools and drawing some chalk marks on the floor, my steering wheel was turned about 30 degrees from center while driving straight, and the entire car would go down the street at an angle on snowy roads.

HAHAHAHA, THAT'S AWESOME!

sbrian2 11-27-2007 04:24 PM

The rear is what is so difficult. It is a balancing act on toe and camber since the same cam bolts adjust both. The front is easy enough. Most just max caster, max camber, and set a little toe out.

cjernigan 11-27-2007 04:26 PM


Originally Posted by s4miata (Post 178524)
didnt 949 racing sell align tools for the miata?

Yeah they're expensive though.

m2cupcar 11-27-2007 08:56 PM

I use a bubble camber gauge, jackstands and thread. It's far from an exact computer alignment, but works well when needed (like on a race weekend). Create some string lines running front/rear off the side of the car that are the exact distance from the car's centerline (measure off the rim center lip) compensating for the F/R track difference. Then measure front and rear of tire walls to check the rear toe. Tape measure and tread grooves works fine for the front toe.

Jefe 11-27-2007 09:23 PM

Here's a good link...
You'll probably laugh but I have one of those cheap toe gauges from harbor freight, but if you practice with it, it works really well for setting toe. I set the gauge on two 2x4's stacked up so the height is always on the same plane.

http://www.harborfreight.com/cpi/cta...emnumber=30167

The hardest part is knowing which side to adjust to keep the steering wheel center. That's why knowing what your thrust angle is helps.

I've been looking for a used alignment machine, but haven't found any close to home yet (want to spend around $1500 or less)

I have an old Camber gauge, but was looking for something 'newer' (or hoping a used machine would fall from the skys) I would probbaly get the one from 949 racing or http://www.racerpartswholesale.com/pdfs/9500.pdf

iWeasel410 11-28-2007 01:20 AM

The hardest part is making sure your car is on level ground before you even begin...

soflarick 11-28-2007 08:08 AM

Yup, the rest isn't too bad. That HF tool is a POS.

fourwhls 11-28-2007 08:30 AM

Here's a home brew alignment method that one of our local autocrosseres wrote.

http://racecarstuff.com/?page_id=2

Braineack 11-28-2007 09:07 AM

I'm pretty sure I'm going to pick up some aluminum square tubing from ACE and build a nice L and bolt a digital level to it. Should be easy and cheap enough. Toe is simple enough with string, but with the toe plates being so chepa i might as well try them, or again build my own.

I'm getting ready for springtime plans so I can get this thing back on the track and kill people with my boooooooost.

m2cupcar 11-28-2007 09:52 AM

here's what we're using on the car I've been racing:
http://www.waltermotorsports.com/v/Racing/align/

IMO this is an ideal solution since it's very portable and easy to use

cjernigan 04-02-2008 12:37 AM

Did you end up doing any of this Scott? I'm considering attempting some combination of these cheap DIY techniques for the next autocross until i get some real suspension and can justify the professional allignment.

grippgoat 04-02-2008 01:59 AM

I thought of a way to measure camber that's indifferent to floor level-ness, as long as the floor is flat. Level floor doesn't really make a difference for toe, I don't think, unless it's way, way off.

Anyway, get a framing square (I think that's what it's called). Long leg needs to reach from the floor to the top of your rim. Set the short leg on the floor, pointing away from the tire. The long leg should now be perpendicular to the floor. Then measure to the bottom of your rim lip to the square, shooting for something fairly close, but not touching the tire, like maybe 1 inch. Call this B. Then do the same to the top lip of your rim, and call this T. Then, measure the vertical distance between the two points you measured, and call this D. Now just do some trig:

camber = DEGREES( ASIN( (T-B)/D ) )

For example, if B is 1.0" and T is 1.5", and D is 16", then camber is 1.79 degrees (well, it's negative, but you know that because the tire is tilted in). Given desired camber, and constant B and D measurements, you can even solve for the T measurement.

T = D * SIN(RADIANS(camber)) + B

So if you wanted 3 degrees, you'd get
1.837 = 16 * SIN(RADIANTS(3.0)) + 1

I'm too lazy to actually try it (Firestone lifetime alignment), but I tested the measurement technique after getting an alignment, and the numbers came out right. It may not be perfect, but it should be able to get you within a tenth or two of a degree.

Also note that if your tires are hella stretched so that you can butt the square right up against the rim, then your B measurement can always be 0, and the math just got easier. :)

-Mike

Braineack 04-02-2008 09:00 AM


Originally Posted by cjernigan (Post 236972)
Did you end up doing any of this Scott? I'm considering attempting some combination of these cheap DIY techniques for the next autocross until i get some real suspension and can justify the professional allignment.

nope. lazy asshole.

hustler 04-02-2008 09:41 AM

I looked in the audi trailer at ALMS a decade ago and saw them aligning an r8 on a rack in the trailer. I need a $50k alignment rack on a trailer.

grippgoat 04-08-2008 03:01 AM


Originally Posted by grippgoat (Post 237004)
I thought of a way to measure camber that's indifferent to floor level-ness, as long as the floor is flat. Level floor doesn't really make a difference for toe, I don't think, unless it's way, way off.

Anyway, get a framing square (I think that's what it's called). Long leg needs to reach from the floor to the top of your rim. Set the short leg on the floor, pointing away from the tire. The long leg should now be perpendicular to the floor. Then measure to the bottom of your rim lip to the square, shooting for something fairly close, but not touching the tire, like maybe 1 inch. Call this B. Then do the same to the top lip of your rim, and call this T. Then, measure the vertical distance between the two points you measured, and call this D. Now just do some trig:

camber = DEGREES( ASIN( (T-B)/D ) )

For example, if B is 1.0" and T is 1.5", and D is 16", then camber is 1.79 degrees (well, it's negative, but you know that because the tire is tilted in). Given desired camber, and constant B and D measurements, you can even solve for the T measurement.

T = D * SIN(RADIANS(camber)) + B

So if you wanted 3 degrees, you'd get
1.837 = 16 * SIN(RADIANTS(3.0)) + 1

I'm too lazy to actually try it (Firestone lifetime alignment), but I tested the measurement technique after getting an alignment, and the numbers came out right. It may not be perfect, but it should be able to get you within a tenth or two of a degree.

Also note that if your tires are hella stretched so that you can butt the square right up against the rim, then your B measurement can always be 0, and the math just got easier. :)

-Mike


Just a quick update on this.... I tried this technique after installing my new FCM bumpstops and dust boots. It worked rather well. Having a ruler that measures in 1/64" was nice, but not really necessary. On a 16" rim-to-rim wheel (my 15" heliums are 16" between lips where I measure), 1mm is 0.14 degrees. 1/64" is 0.06 degrees.

Here's the overall workflow I did:
0) Fire up excel to figure out what the delta between T and B needs to be for your desired camber. I was shooting for about -1.3, or 24/64".
1) get the car on the ground and settled.
2) Position the square so that B is either 1" or 2". With 0 camber, the square would hit the fender at B = 1"
3) Measure T, and subtract B from it.
4) Now figure how how much you need to change T in order to get your desired camber. In my case, B was 2" and T was 2-2/64", so T-B was 2/64. I needed to move it by about 22/64"
5) raise up the corner of the car, so that the top of the rim is up at the top of the square, and you can get at the camber adjustment bolt
6) re-measure with B at 1" or 2", and figure out T. Take the delta you need from step 4, and figure out what your target T is with the car up in the air. As it happened, with the car in the air and B at 1", T was at 1-50c/64. Since I needed to move 22/64", that meant my target T was 2-8/64".
7) Adjust camber and re-measure with the car in the air until you hit your target T.
8) Put the car back down, re-settle it, and double check. Should be within 1/64" or 2.

I think doing the rear would be a bitch, though, because you'd have to adjust both bolts equally. In the front, camber doesn't change too much with caster.

I also stringed up the car and discovered that I'm pretty good at eyeballing front toe. :) I also found that the overall front and rear toe is close enough to get me to the alignment shop.

-Mike


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