G-force readings, what's a good value?

[emperor_lunchbox]

I have a 95 S14.

I have collected some G force data on my car and my readings are as followsleft turn - .78right turn - .72

Acceleration - .56Braking - - .41

I have Megan Coilovers and 195/55/15 all economy performance radials on a poorly setup suspension and stock S13 alloys

I don't really care about the acceleration and braking right now because I am basically stock, except intake, exhaust and brembo cross drilled rotors. I am concerned about the cornering though. These are the values I got from just basic highway driving, I think the max's we from the on ramps

A friend of mine has a mostly stock Jetta except he has wheels and tires, we did the same test to him his readings were:Left Turn - .61Right Turno - .60

Acceleration - .37Braking - -.31

Like I said, Im not too concerned with the acceleration or braking, but for the cornering that is a little too close when I have coilovers and he has a stock suspension. Is there really a big difference between .61 and .78?

Im sure once I get the new wheels and tires on and get the alignment done they will improve but, are these readings good, if not what is a good reading?Thanks.
Modified by emperor_lunchbox at 8:26 AM 9/3/2006

[AZhitman]

Some of the best-cornering cars in the world pull just over 1.0-g lateral...

You can inprove on your numbers, I believe the 240 will do better than that.

1g is the "gold standard" goal. Hard to attain, but possible.

Sticky, lower-profile tires will bump the lateral g's up significantly.

[C-Kwik]

Is there really a big difference between .61 and .78?

A 0.17 G difference is pretty substantial in cornering. Just go poking around in magazines and compare the difference between cars that reach about 1.00G's and those that reach about 0.83G's. At 0.83G's you're going to find very few performance oriented cars.

As far as your actual readings, I'd only look at the relative numbers. Even a mostly stock Jetta should be capable of hitting more than 0.80G's. Assuming you are doing this on the street, there are outside factors that can skew the absolute readings as you are likely not using a 200 or 300 foot diameter circle on an actual skidpad that is flat and in great condition. And magazines also get toe drive around it trying find the best way to balance throttle and steering to produce the best numbers they can.

[240TweakerNewbee]

I did .97g's in my car the other day. I know this because my friend has a 2006 Zo6 Corvette and he was riding door to door with me (me on the inside) at the exact same speed around a corner when he said his HUD read 0.97g's. I’ve driven that Zo6 and hit 1.05 (its rated at 1.02, but will do much more), but my 240 couldn't do more than 1g without sliding.

There is little left to improve on my suspension setup without going to coilovers, I've done all the links, arms, powerbrace, cusco anti-swaybars, strut tower bars, bushings etc.. And I'm running Toyo T1-R's.

Coilovers are next I guess, I'm just not in a hurry to kill what’s left of any ride comfort, and as it sits there is not much out there that will touch it on acceleration and cornering, so what would I do with more performance besides get myself a nasty ticket.

[240 GTR]

i have a g-tech pro ss. i went road racing in my s14. according to the g-tech, i pulled a 1.09. that is on a completely stock car. the tires are michelin energy mxv4 plus (econo tires)

[naed240sx]

Ughh a lot of bad data going around in this thread. As C-Kwik said, when using those g-force box things, or any in-car readout, the number that you hit means absolutely nothing. They are far too innacurate. You can be pretty sure that they are precise though, which means that they are good for recording consistant numbers with a given setup. This allows you to tweak suspension stuff on the car, and see if you can get a gain in lateral g's. Neither number by itself will tell you anything, but you can certainly make conclusions from comparisons.

As Greg said, 1.0 g is pretty much the gold standard that everybody aims for, seeing as how this is around what the top sports cars pull. Remember though, this is not a "peak" lateral grip number. This is an average. They get these numbers from driving around a large flat skidpad in consistant circles and timing how long it takes to make a few rotations. From there, physics will allow you to find the lateral grip data. What you end up with is the average amount of lateral g's that the car was pulling for the ENTIRE length of the circumfrence, not a maximum number. Hitting 1.0 g maximum is not too entirely difficult. Hitting an average of 1.0 is.

Of note: Sport compact car hit 1.0 g with their s13 project car. They were running coilovers with 6/5 springs, aftermarket suspension links, a helical differential, front and rear adjustable sways, and some 225/45/17 Falken Azenis 215's. The tuning of the car is the most important thing. You have to spend time trying different alignment, sway and damper settings.

[emperor_lunchbox]

I see. I know what I am averaging while driving. During normal drving its normally around .25-.40 depending on the turns and on-ramps are a bit higher .45-.55.My acceleration is normally .15-.25 for normal drvingand braking is around -.07 - -.13

Seeing what I my max is I think I need to do some more suspension work.

[nismofly]

^^ again though, those numbers arent on a 200 ft skidpad, which is where the golden 1.0g came from

the golden number might be completely different if the size of the skidpad changed

for example, while on a 200 ft skidpad F1 cars "only" () pull around 2.0 G's, during races depending on the radius of the turn they can go well over 4.0 lateral G's

[emperor_lunchbox]

ok, so how can I set up an as close as it gets test to see where I am at?

Do i make a 200 ft circle? and just drive around it?

[AZhitman]

If I'm not mistaken, the surface and diameter have to be consistent with some unknown standard...

Dean's pretty much laid it out for you: Don't go around telling people your car pulls 1.09 G's, since that's momentary and not constant.

We're all about dispelling "ricer math".

[gepeto]

I still think hitting 0.8g on an onramp is a bit risky...at least on Montreal crappy roads hehe!

[C-Kwik]

The skidpad measurement in magazines is not momentary. Most cars can hit higher lateral acceleration for an instant. If you look at a skidpad datalog, you'll find it's not perfectly linear. While the aim isto try and flatten out the curve as much as possible to get the most accfurate reflection of steadystate cornering, it's quite hard to keep a car in that state for very long. Skidpad numbers are actually a two way average of the mathmetical average g force obtained in the test.

My car Stereo in the maxima has a G-meter built in. I tried it out once and while I could really only test it on surface roads it does log the peak G. With some rather expensive tires that I had leftover from the G35, I pulled off only a .72 (momentary). The meter is not really calibrated well it would seem. I'm sure the actual peak G should be higher.