[tyler_sti]

^ Or make a dedicated day to the tests. That would be awsome.

[IlliniSTi]

Originally Posted by fullerton

the problem is the location. i wonder if the scca would let us do something before/after an auto-x.

Most SCCA TnT's have a skidpad.

[stretch]

This Passport GT2 is much better than I expected. The GT2 shows a graph of G's, so you can somewhat tell what your average G's were. Peak G's are held for less than 10 seconds (basically until that peak scrolls off the graph). There are a slew of different modes, and I think one is the friction circle with a scrolling 10 second history chart (I just need to make sure this is a friction circle calc and not the peak between lateral and longitudinal).

This would be super valuable because if you can maintain your peak G's on corner entry, apex, and exit, then you're making the most of your tires through the entire turn.

Tilting the device results in a reading of cornering G's, so body roll will be perceived as higher cornering force. A GPS or 3-axis G-meter won't do this.

What surprises me is that the measurements from this thing are pretty remarkably stable. My G-tech didn't seem very consistent. Thing thing seems quite consistent and reliable. I always pulled the same G's accelerating, for example. At rest, the gauge didn't flutter at all- it stayed put exactly on 0G's.

So, maybe this would be a fun way to do "proven power bragging" for suspensions after all. It's definately not accurate enough for very fine-tuning, but I think it is accurate enough to be more than just a toy.

[Mykl]

Sounds like a neat idea, but like dyno e-peen testing you can't exactly take it seriously. Way too many variables in play. My car has thousands in suspension crap bolted to it, but my 245 RE-01R's would get murdered by some AS car with 275 V710's.

I do wish I had access to a nice, large, open stretch of pavement that I could do some real testing on. Best I can do here is interstate on/off ramps.

[MGizzle]

Get the MaxQData system. It is soo cheap even my broke a$$ ordered one. I used one from my friend and the things you can do with it are endless. I am in love with it ever since and have learned more about my driving then ever before. You can use the GPS lateral G's and the internal one. Hence, you get two readings. Also, you can read from your OBDII and you will notice when you are in steady state, hence you know your G's should be flat and maxed out. At the same time, you can look at your GPS and Vehicle (OBDII) velocity to determine braking. You can notice when your speed starts dropping. Very simple and you got GPS and actual sensors to compare results.

Finally, if you have a steering sensor you can do the MOTHER SUSPENSION TEST. Constant circle vs. speed test. This will 100% tell you what kind of understeer/oversteer coefficent your car has and you can tune accordingly. It is not steady state since you are changing speed hence damper settings matter. Also, you can throw a figure 8 if you are really worried about transients. I don't think our cars have a steering sensor but the MaxQData system has plenty of inputs if you want to add one. This is my goal and should be a basis tuning tool for any suspension design.

Finally, MaxQ gives everybody the software to view plots hence members without it could even look at plots from people using them. Finally, all the files are in the same format and everybody could swap between plots easily.

Also, GPS means you can verify distances etc. hencce you will not have the "about 100ft skidpad" etc. things going on. You could even do a full error calculations but who the heck wants to go through that headache.

Finally, engines are power making devices that can be measured easily = dyno. Good luck with suspensions. If there was a tool I am sure OEM's would be using it. Right now the only thing I can think of is the post shaker but again, the suspension has so many parameters that the variance is infinite. Accelerometers are so sensitive (and they should be) that readings vary significantly from time to time and not to mention car to car.

Hence, I would start with a base line and this would be preferably 3-5 STOCK STi's with very low miles on them tested at the same time (about) at the same place with the same tools. Man, I just can't get over how many things effect suspension readings.

[Mykl]

I *think* the '05 STi received a steering sensor input for the DCCD computer.

[RaceComp Engineering]

bump for a good thread.........

Myles

[supermarkus]

Originally Posted by Mykl

I *think* the '05 STi received a steering sensor input for the DCCD computer.

Unfortunately no, but it did get an additional yaw sensor input. Steering didn't come until 06

[MGizzle]

^^^ yeah, that is what I found out the "hard" way. Kinda sucked. That sensor is so important if you ask me I can't even explain it. It opens up a whole new level for chassis tuning.

[antonch]

Here is an idea that I think might work. Run say a G-tech unit in data collection mode to make the friction circle from an auto-x session. Can get a pretty good idea of what the car's capabilities are for that day. Of course you will always have variation due to tire temps and such.

What do you guys think?

[MGizzle]

that is basic steady state data. In my opinion steady state is good for braging about the max/peak G's you achieved. However, these vary so much even if you don't change the set up. Hence why "suspension power bragging" is hard.

Finally, transient response (when your dampers/chassis etc. actually does work) is in my opinion even more important because that will tell you how FAST you achieved your max/peak lat g's etc. This one is a mother#*$#$ to measure.

This is why Motor Trend uses a MT figure 8 test instead of just a skidpad etc. to compare grip between cars. Then they run the slalom course.

The only way in my opinion to do "suspension power braging" is to hook a car up to a knc/4-7 post rig and compare them. That is it. Introduce a driver and temp changes into the equation and everything goes to shizz.

[Okeyd57]

This IS a good thread ! My 06 STi has two protuned maps for my AP. My lower 20G map is 336hp/354tq, and my 20G high map is 350hp/370tq. I have the Prodrive RB320 suspension, frt/rear sways, group "N" motor/tranny mounts.

Wouldn't I get different "G" results from each map ? There are just so many variables involved, I don't see how the results could be compared with any confidence.

[flatthump]

But what about tires?

[MGizzle]

It doesn't matter what components you have on your car. That is the point. Hence why we need a "standardized" test to compare "performance" to each other. The "device" measure "suspension/chassis power" is the variable here I think.

[antonch]

Originally Posted by Okeyd57

This IS a good thread ! My 06 STi has two protuned maps for my AP. My lower 20G map is 336hp/354tq, and my 20G high map is 350hp/370tq. I have the Prodrive RB320 suspension, frt/rear sways, group "N" motor/tranny mounts.

Wouldn't I get different "G" results from each map ? There are just so many variables involved, I don't see how the results could be compared with any confidence.

Don't car dynos also have a significant amount of variability as well? A car can vary from session to session quite a bit. You also have guys that ice intercooler+piping to improve conditions.

So this would be like a peak dyno queen comparison.