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Auto-x alignment advice / sway bar help?

Old 05-16-12, 11:42 PM
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Auto-x alignment advice / sway bar help?

I am getting my FC ready for another season of auto-x. Last season I mostly focused on fixing broken parts and just trying to keep it running, and all of its engine oil and coolant in the right places. This year I am trying to prepare a little better.

I am wondering what alignment specs you guys would recommend for me. Here is what I currently have:
87 RX-7 GX (this might be a Canadian only trim level?) non-turbo
Tokico Blue shocks on all 4 corners
Racing Beat springs on all 4 corners
Stock 14" wheels with Sumitomo HTR-200's on all 4 corners
Stock sway bars - this leads to a question later...
Prothane poly bushings on front and rear control arms

I found with these parts and a completely unknown alignment I am eating the outside shoulder off the tires, the car feels very neutral and slow to change direction and I seem to have very close 0 camber.

I am planning to take it to a shop and have it aligned now that I am done messing with the suspension. Tie rods, ball joints, lateral links and all other bits are in good shape.
I was wondering what you guys would recommend for alignment settings?
I don't know a whole ton about this but I was thinking slight toe out on the front, 0 toe on the rear, as much negative camber as I can get on all corners and as much caster as I can get on the front. On this topic, what do you guys think of adding camber bolts to the car to get more negative camber? I've seen some around that offer 1.25-1.75 degrees of extra camber. Are they a good idea?

Also, with the prothane kit they provided some sway bar bushings. I noticed these are easily 2mm too large to fit my current sway bars. Does anybody know what bars should fit these bushings?... It seems the GX model comes with smaller-than-standard sway bars on the front and back and I would like to bring them up at least a little bit in size. If the correct size bars are on a GXL or other trim level perhaps I can locate them on the cheap and get a nice little upgrade for not much money
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Old 05-17-12, 10:38 AM
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you're on the right track.

have a read here http://2ndgenrx7.freeservers.com/grassrootsproject.html they made some really small changes to the alignment, so they give a good starting point.

i think the GX model is the same as our SE model, or maybe its like our base model. either way almost every other model came with larger sway bars. off the top you have a 22F and maybe 14mm rear? the upper S4's come with 24 and 16, and then the S5s are 24 and 14? i think there are 3 different rear bars and 2 fronts, although you should double check the parts catalog. either way you should be able to find the bigger bars for nearly free.

its eating the outside shoulder because when the tire has zero camber sitting still, when you are in a turn the car leans, and so the tire leans and you're mostly cornering on the part that's wearing. so yeah you need more negative camber. i've never tried camber bolts in the Rx7, usually camber plates, but there is no reason the bolts won't work

so find the big bars, align the car, and enjoy!

for further reading http://farnorthracing.com/autocross_secrets.html
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Old 05-17-12, 12:46 PM
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You're on the right track with your ideal camber settings, but both camber and caster aren't adjustable at all stock. and because you have poly bushings in the rear control arms you can't adjust them individually side to side either, you'll have to get a subframe tilting camber link like ground control or TCS makes

http://banzai-racing.com/store/86-91...amber_bar.html

for the front, I too have never used camber bolts on my rx7, but I used them on my auto-x corolla and they worked fine. I had to double up (one in the top and one in the bottom hole) to get the ~-3* I was after, but they worked. I still prefer campber plates though (that replace the strut top mount). ground control sells very nice ones that adjust front caster too.

my auto-x alignment specs are:
front:
-3.5* of camber
1/8" toe out
7.1* of caster

rear:
-2.5* of camber
1/8" toe in

you don't need settings that extreme on the tires your running though. I have hoosier A6s slicks on my car. I would aim for at least -1* of camber prefferably closer to -2-2.5* the rear maybe about -1.5-2*
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Old 05-17-12, 02:56 PM
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I didn't even think to check what can be adjusted without adding adjustable parts, I am just used to owning cars where camber and caster are adjustable.

So on the front the only adjustment you can make is toe, and same on the rear?... Hardly seems worth getting an alignment for that, I think I'll just throw camber bolts in it (as they are ~$15 instead of $100+ for camber plates) and align it myself to make sure the toe is set properly. I have zeroed both toe adjusters on the back so I guess it is just the front toe I can tinker with after that.

Thanks for the information

I am going to try to find a S4 GXL that is being parted out locally and snag the sway bars off it, that should net me a pair of the big bars.
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Old 05-17-12, 03:16 PM
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Originally Posted by Zero10 View Post
I didn't even think to check what can be adjusted without adding adjustable parts, I am just used to owning cars where camber and caster are adjustable.

So on the front the only adjustment you can make is toe, and same on the rear?... Hardly seems worth getting an alignment for that, I think I'll just throw camber bolts in it (as they are ~$15 instead of $100+ for camber plates) and align it myself to make sure the toe is set properly. I have zeroed both toe adjusters on the back so I guess it is just the front toe I can tinker with after that.

Thanks for the information

I am going to try to find a S4 GXL that is being parted out locally and snag the sway bars off it, that should net me a pair of the big bars.
the strut top moves a little too, i was able to get -.5 camber out of my last S4 just by using all the slack/tolerances in the stock parts...
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Old 05-17-12, 03:28 PM
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Originally Posted by Zero10 View Post
I didn't even think to check what can be adjusted without adding adjustable parts, I am just used to owning cars where camber and caster are adjustable.

So on the front the only adjustment you can make is toe, and same on the rear?... Hardly seems worth getting an alignment for that, I think I'll just throw camber bolts in it (as they are ~$15 instead of $100+ for camber plates) and align it myself to make sure the toe is set properly. I have zeroed both toe adjusters on the back so I guess it is just the front toe I can tinker with after that.

Thanks for the information

I am going to try to find a S4 GXL that is being parted out locally and snag the sway bars off it, that should net me a pair of the big bars.
I frankly wouldn't bother with thicker stock bars. I'd just keep the rear you have and upgrade the front to the big 1.125" Suspension techniques bar. it's like $150 for a lot more roll resistance.
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Old 05-17-12, 03:44 PM
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Here is a fun chart:
http://www.oakos.com/wrx/swaybarchart.htm

yes it's for WRXs, but the percentage increases should be the same.

22->24mm front bar is a 42% increase in roll stiffness where as:
22->29mm (ST bar on max stiff) is a 202% increase in roll stiffness
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Old 05-17-12, 04:42 PM
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202% sounds well worth it. Last time I asked the sway bar question I was told not to touch them as I would start lifting inside tires. That didn't sound quite right to me but as advised I left them alone. That is, until I discovered that I don't even seem to have big enough bars to be the "stock" bars...

I am going to try to swing a bit more budget for the auto-x car this year and see about getting the ST bar, but so far I have exactly $0 left over to add more new parts to the car. If I can grab the GXL bars for free (or nearly free) they don't cost me anything to mount so they would be a nice little upgrade given the cost.

Thanks for all the advice so far, am I correct in understanding that you can only adjust toe with all the stock suspension bits on the car? If so I just saved $110 for an alignment that wouldn't do anything.
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Old 05-17-12, 07:25 PM
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picking up front tires doesn't really matter too much. I see national level auto-x cars do it all the time. The trade off is definitely worth it. I have a 27mm whiteline bar on the stiffest setting (~28mm) and I pick up a wheel occasionally, but that's with slicks, short stroke front struts, 300hp, and no rear sway bar. you'll be fine.

It's the rear you have to worry about which is why most people suggest either not upgrading the rear bar or getting rid of it all together (on a NA I'd leave it)

yes, all that's adjustable stock is toe. the front with the tie rods and the rear with the cam bolts on the outside of the control arms
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Old 05-17-12, 10:07 PM
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Another useful tip when running street tires is to increase the air pressure. I have run in a street tire class and it helped to air up. A tall sidewall tire like what you are probably running will probably benifit more than a low profile tire.

Hope it helps,
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