Logging suspension movement/travel *Update*

[nathaninwa]

I'm looking to log suspension reaction at the strip and I having thoughts of mounting a tps front and rear. Or maybe something like a load leveling sensor. Do any of you have a good sensor like this before I do something like a tps?

[Raymond_B]

A TPS would certainly be cheaper than one of these! http://www.racepak.com/Drag_Racing/Travel.php But I like the idea of using a shock like device, I wonder if there's anything from OEMs available? Surely there's something out there that measures ride height?

[nathaninwa]

Ford and BMW use them. Retail is about 100 sensor tho

[racingmini_mtl]

Another slightly cheaper alternative for the racepak sensors: http://www.ebay.com/itm/331032223527

Jean

[old guy]

How much travel, accuracy and what kind of output?

[kjones6039]

How much travel, accuracy and what kind of output?

According to the item description:

Stroke Length: 0 to 4.0" (0 to 100 mm)
Mechanical Stroke Length: Stroke Length + 0.12" (3 mm)
Non-Linearity: +/- 0.08% of full stroke
Resolution: Infinite
Repeatability: 0.0004" (0.01 mm)
Maximum Operating Velocity: 5 m per second
Element Type: Conductive plastic
Output: 0 to 100% of excitation voltage
Element Resistance: 4.0" range unit = 4.0K ohm (+/- 10%)
Maximum Excitation Voltage: 4.0" range unit = 24 VDC
Current Draw: ~10 mA (nominal)
Output Cable: 3 conductor with drain, 22 AWG, PVC jacket, 3 foot long
Operating Temperature Range: -40 to +195°F (-40 to +95°C)
Temperature Drift: +/- 400 PPM/°C
Humidity: 95% Max. RH (non-condensing)
Liquid & Dust Protection: IP64
Shock Rating: 50g (single hit), IEC68-2-29:1968
Vibration Rating: 20g, IEC68-2-6:1982
Housing Dimension (O.D): 0.9 inch (22 mm)

Looks promising, IMO

Ken

[old guy]

If he only need 4" of travel, you can get linear pots with that much travel and make your own for a lot less than what that cost's.

[nathaninwa]

I wasn't sure if your post was for me or not. 4 inches could be enough. I can mount them at any point on the suspension and calibrate the input to show actual. Accuracy, if it's with in like 1/4 inch I bet it's fine for what I'm doing and voltage will be 5 volts for use with analog inputs

Tell me more about these pots.

[nathaninwa]

I found some 4 inch slide potentiometers on eBay for a great testing price. Thanks for the idea

[racingmini_mtl]

I found some 4 inch slide potentiometers on eBay for a great testing price. Thanks for the idea

I'll be interested in seeing what you come up with.

Jean

[misplaced_vol]

I definitely will be interested to see what you come up with.

Here some in different lengths
http://thesensorconnection.com/linear-t ... end-joints

[nathaninwa]

I will post up what gets done. I'm still finishing the car for chassis tech in two weeks and then the first local race is mid April. So I bet it's the first part of May I start to want to datalog this

[chips60bug]

What ever came of this?

[nathaninwa]

I spent the summer working with suspension and engine stuff, but have the analog setup and working with an IR sensor as well. The car is on stands and prime time for me to install these

[nathaninwa]

Update on this finally. Delphi ER10031 is a gm suspension sensor that rotates like a tps. I have one mounted to my lower inner front fender well and attached to the lower control arm and just installed one off the rear frame rails that attaches to the panhard mount

The front came in handy for setting up the alignment and I just did the rear sensor to help figure out chassis lift or squat on the hit while trying differnt bar arrangements on the 4 link

[whittlebeast]

Search Ebay for

Tahoe Yukon Escalade Right Front Ride Height Sensor 15098629 Dorman 926-784

I found one for $35. You feed it 5v and ground an it returns 1.5 to 4.5 volts over about 4" of travel. Total travel is about 6" We think DIY has the correct matching connector.

Andy

[whittlebeast]

Nathan

Could you post a street or race data log showing the wheel sensor data.

Andy

[nathaninwa]

Sure. Let me charge the laptop and I'll post some in a bit

I did have a hard time with the connector, not a lot of info out there on this sensor. Searching gm's picture reference I found a Pico number 5603PT that works with minor trimming on the side, but the pin centers and seal shape/connector lock are perfect

Not knowing the pinout I was able to use my ohm meter to determine the center pin is refeence voltage back to the ecu, then just 5v and ground on either side, wire it so you get the desire plus or minus feedback that works for you

[nathaninwa]

Here is the log from my last 1/4 mile pass. You can see a little wheel slip, traction control take care of it, the front end dips and recovers, then you can see a slight dip in the track, and the front slowly come down from Aero over the rest of the pass, and it dive hard when the chute comes out! It would actually stay nose high the entire pass until I lowered it some more upfront and went from a 125lb spring to a 150lb shorter spring.

This is my best MPH todate of 171.7mph. If I can just suck it up and launch it harder it could be a high 7.9x pass

Having this data allowed me to see before where the front was riding at and find out that I had 1 inch of toe out in my setup causing my twitching issue. Car drives straight as an arrow now. I'm excited to work with antisquat this coming weekend


Edit, you can also see the either the cars reaction time, or the slight delay in suspension movement to vss input
https://youtu.be/jmoMYCe9x7A

https://youtu.be/kYwkg06rRkY

[whittlebeast]

Way cool

Is there some reason you are only logging at 16 samples per sec. If you are on MS3 Ultimate, it should be good for at least 200 samples per sec.