Recommended Alignment Settings

[sparky]

I don't know exactly why, but this is exactly what I was told by the person at Techline (Acura U.S. HQ) who has been tracking all NSX problems since the car was introduced in 1990. He's more familiar with the NSX's technology than anyone else in the country.

personally I'd prefer it's true (less toe = less snap o/steer) especially as I've got the full compliment of non-compliance parts in the rear, and would much prefer a more "normal" toe setting, like say 2mm, to avoid tyre wear and reduce acceleration lost to resistance / drag of skewed wheels. I guess I'd better go adjust and test ...

 

[TURBO2GO]

Nice thread.

I just told my alignment guy to go with Billy's middle post (on his personal car) here:

http://www.nsxprime.com/forum/showpost.php?p=1407107&postcount=17

But now after reading this I am wondering if 4mm rear tow would not be better. I am deathly afraid of snap oversteer on this car having experienced it twice with no recovery. I was lucky nothing was around me.

 

[Honcho]

*delete*

 

[Honcho]

I don't know exactly why, but this is exactly what I was told within the past year by the person at Techline (Acura U.S. HQ) who has been tracking all NSX problems since the car was introduced in 1990. He's more familiar with the NSX's technology than anyone else in the country.

This is the text from the wiki. Do we know who "KJ" is?

What the rear tires are doing:

The rear tires pull in (RR pulls to the left, LR pulls to the right) slightly to follow the alignment settings. The purpose of this is to remove the compliance or "slop" associated with moving parts, (ball joints, tie rod ends, pivot points, etc.) AND to help keep the rear of the car tucked IN when in turns.


Also, this is from Don Erb at Comptech USA:

Rear toe should be about 3-4mm toe in. The more toe in you have on the rear the more stable the car will be down the straight and the more stable understeer you will have in the corner. Some factory settings on certain models had up to 8mm toe in. This was to keep the car more stable. The tire wear was very high and many owners complained about it, so the next year they went back to lower settings in the 4-6mm range. In an ideal world, as the suspension moves the toe would never change, but it does. This is why we make the low compliance rear beam and toe links. If you don't believe me, do this simple test. Look at the rear wheel out your door and roll you car backwards and hit the brakes, see the wheel move in and out? This is toe change! The less you have the better.

I use the information in the NSX service manuals regarding ride height. The suggest measuring points are center of front control arm bolt and center of rear toe am bolt to perfect level rack surface. Using fender to tire height or jack points makes no sense to me. You're aligning the suspension geometry so measure the suspension height not the body or body panel height.

Measuring by the wheel opening to tire or jack point to ground for alignment is like measuring the tire pressure by looks or pressing on them with your fingers. Not very accurate but it tells you something I guess.

Roughly, the range given in the NSX service manuals is 1.5 to 1.9 inches difference from front to rear rake at the measuring points the manuals show.

How this translates to the body rake measuring from the jack points I really have no idea but I know it's not going to be the same. Probably significantly less, F/R but again, it's just not a very accurate way to measure.

Thanks Joe. I figured if it was coming from Shad, it was reliable information. Should I align and balance with me in the car? Also, do you know why there is a height range in the service manual? I assume it is for full fuel and empty tank?

 

[RYU]

Has anyone had any luck with home alignment tools? I've been considering buying the Fastrax or Intercomp alignment tool for years but not sure if there's a better solution out there. The Fastrax isn't as accurate as a laser alignment but if you're doing many alignment changes it should pay for itself in no time. The Intercomp is a bit more expensive and is laser aided but still relatively cheap.

<iframe width="420" height="315" src="http://www.youtube.com/embed/ZwyfUXsXTV4" frameborder="0" allowfullscreen></iframe>

 

[LJSB]

Should I align and balance with me in the car? Also, do you know why there is a height range in the service manual? I assume it is for full fuel and empty tank?

The manual for this car doesn't have a spec they want for weight in the car like some others do. The alignment specs they give is for a empty car and regardless of a full or empty tank.

Since you can't adjust the ride height on the stock car I believe it is given more so you can detect if the shocks and /or springs are too worn, fatigued and need replacement.

Bear in mind the service manual data is not for track use and dialing the car in for a specific track, set of tires or adjusting for the driver's skills/needs.

Do you have adjustable coilovers?

 

[Honcho]

The manual for this car doesn't have a spec they want for weight in the car like some others do. The alignment specs they give is for a empty car and regardless of a full or empty tank.

Since you can't adjust the ride height on the stock car I believe it is given more so you can detect if the shocks and /or springs are too worn, fatigued and need replacement.

Bear in mind the service manual data is not for track use and dialing the car in for a specific track, set of tires or adjusting for the driver's skills/needs.

Do you have adjustable coilovers?

Thanks Joe, this is really helpful info. Yes, I have adjustable coilovers. I want to lower my car by 19mm all around (NSX-R spec, as I have those spring rates), and then adjust only slightly for corner balance. I just was not sure from where I should start. Given your explanation, I think it is best to use the F 180mm and R 223mm spec suspension heights, as these would correspond to the brand new springs and brand new tires condition (which I have). My 19mm drop would therefore yield F 161mm and R 204 mm.

After researching various other threads and the wiki by people who do set up the car for track duty, the consensus appears to be:

1. Set ride height empty car
2. Corner balance with driver in car
3. Align empty car to desired spec

The only discrepancy I found was this statement in the wiki by Prime members [MS], [HS], [KJ]:

Now for the critical advice. Have your car aligned with you in the car! If they have rules about customers in the shop, make sure they put your weight in the driver's seat. I tried it both ways and found a significant difference in specs, to the tune of more than half a degree in camber and 3mm toe.

This made me hesitate- I would hate to spend all this time and money getting the car corner balanced and aligned, only to have everything thrown off the minute I sit in the car! In that case, I might as well just set the ride height equal and align it empty. I just want to make sure I'm doing this the right way the first time. This is my first experience with a height adjustable suspension.

 

[CL65 Captain]

Has anyone had any luck with home alignment tools? I've been considering buying the Fastrax or Intercomp alignment tool for years but not sure if there's a better solution out there. The Fastrax isn't as accurate as a laser alignment but if you're doing many alignment changes it should pay for itself in no time. The Intercomp is a bit more expensive and is laser aided but still relatively cheap.

<iframe src="http://www.youtube.com/embed/ZwyfUXsXTV4" allowfullscreen="" frameborder="0" height="315" width="420"></iframe>

Garage has to be PERFECTLY FLAT or it trows everything off. How many times do you have to DIY to make it cost effective vs $150 alignment done with a laser machine while I go next door and get lunch?

 

[RYU]

Garage has to be PERFECTLY FLAT or it trows everything off. How many times do you have to DIY to make it cost effective vs $150 alignment done with a laser machine while I go next door and get lunch?

Obviously one would need a perfectly flat garage. Though, if you read thru the specs the Fastrax unit has provisions to account for unlevel surfaces.

After two $150 sessions + $7 of McDonalds the fastrax will pay for itself and you might even lose some weight.

 

[RYU]

Thanks Joe, this is really helpful info. Yes, I have adjustable coilovers. I want to lower my car by 19mm all around (NSX-R spec, as I have those spring rates), and then adjust only slightly for corner balance. I just was not sure from where I should start. Given your explanation, I think it is best to use the F 180mm and R 223mm spec suspension heights, as these would correspond to the brand new springs and brand new tires condition (which I have). My 19mm drop would therefore yield F 161mm and R 204 mm.

After researching various other threads and the wiki by people who do set up the car for track duty, the consensus appears to be:

1. Set ride height empty car
2. Corner balance with driver in car
3. Align empty car to desired spec

The only discrepancy I found was this statement in the wiki by Prime members [MS], [HS], [KJ]:

Now for the critical advice. Have your car aligned with you in the car! If they have rules about customers in the shop, make sure they put your weight in the driver's seat. I tried it both ways and found a significant difference in specs, to the tune of more than half a degree in camber and 3mm toe.

This made me hesitate- I would hate to spend all this time and money getting the car corner balanced and aligned, only to have everything thrown off the minute I sit in the car! In that case, I might as well just set the ride height equal and align it empty. I just want to make sure I'm doing this the right way the first time. This is my first experience with a height adjustable suspension.

Analysis paralysis my friend. I think you're splitting hairs at this point

 

[LJSB]

The only discrepancy I found was this statement in the wiki by Prime members [MS], [HS], [KJ]:

Now for the critical advice. Have your car aligned with you in the car! If they have rules about customers in the shop, make sure they put your weight in the driver's seat. I tried it both ways and found a significant difference in specs, to the tune of more than half a degree in camber and 3mm toe.

If you believe not sitting in the car or having your weight in the seat during alignment will make a difference in the settings that could frustrate your ability to get the max out the car and your driving experience, then do it. What could it hurt? Right?:smile:

 

[TURBO2GO]

My new pickup line is:

"but baby I already had my car corner balanced with your weight in my passenger seat!"