There has been so much talk about the C8’s understeer yet I haven’t read lots of complaints by actual C8 owners who hate the set up or actual have tracked the car.

My question is, did all the OMG it has understeer take away from your joy and performance of your C8?

You Tube

 

If you watch the pdr of hipo driver (aka poorsha) and speed phenom they both appear to have some decent understeer. Maybe just more time with the car and figuring out height adjustment and align for specific set of tires etc. All mid engine cars have it. Go back to jim mero's assessment. And he even mentioned no matter what did we couldn't get rid of it (years before this C8 was finalized). There's give and take.

 

nope none and not clicking that crap

 

Bigger rear sway bar,,,,,,

 

The track alignment takes out quite a bit, correct? What's the front camber on track alignment?

 

Most of you will smell the **** from your pants before you have a whiff of understeer.....
Please read a couple of Ross Bentley books ,and show your track lap times first before criticizing .
Thanks in advance .

 

how about if you run a car on track every now and then or went to spring mountain? Would you experience understeer at some pont and recognize it? Or better yet. Drove a fwd car in the rain or snow and turned to hard or quick?

Or better yet. Mashed pedal on a rwd car and turn the wheel once moving when all the weight is transferred rearward? Would you know understeer then??

 

With poor driving skills you can get anything to understeer.

 

I tried to break it down here

Most every car understeers under throttle from the factory. With a track alignment the C8 seems to oversteer on corner entry, is neutral mid corner, and understeers at full throttle exiting the corner. You can adjust this with the throttle though as a small lift gives the front end more bite.

 

Ahhhh. Poorsha. Sometimes you're like batman. You show up and make everything better. Thank you

 

Very nice analysis. Thanks for taking the time to do this. Your presentation really shows the power of the PDR as an analysis tool, too.

 

If you are fast on track, you understand the relationship between rotation rate and trail braking. The car is mid-engine so it can have higher rotation rates. There is absolutely no reason in the world you should be full throttle on corner exit and experiencing understeer. If you are getting anywhere beyond feathering in the throttle off the apex you were too slow to begin with. This is why timing your brake zone has to be within a couple feet of one another and one should be doing a very delicate dance with the left foot to get the car to the apex to begin with. WOT should happen as you finally un-wind the wheel; if you can before that point you were just incredibly slow at the apex, probably pissing off the Miata on your tail that just gave you a point by in the straight away.

 

Yup. Easily tunable with rear sway bar stiffness.

 

First, I didn't say you go WOT at apex and if you are neutral mid-corner near the limit the car is pretty neutral. My experience was that this car does not reward trail braking as it tends towards oversteer at turn-in and trail-braking makes it worse. See the video of me and the Ferrari, the big bobble in turn 1 was because I came in hot and tried to do some extra trail braking which caused the back end to come around. The loose on turn-in is probably the bigger issue with the car and I know GSpeed recommends lowering the car to improve the rear grip on turn in but I haven't tried it yet.

The understeer is typically as you get to WOT exiting the corner - you can see that I have to breathe off the throttle to get a little more front grip as the car starts to wash wide on exit. However, I'd rather have that than a car that steps out under throttle exiting the corner as I can more easily manage putting the power down without making big time-killing corrections. Second, with PTM you generally want to go WOT as soon as you can because PTM will do a better job than the driver of knowing exactly how much power the car can put down - most modern race cars with TC are similar as the point is to get more power to the wheels sooner.

 

I've heard a couple of folks suggest that and it seems like a good suggestion. Is anyone making one though? I reached out to Hotchkis and they said they would be making bars for the C8 but didn't elaborate on details or timing.

 

Sounds perfect

 

I haven't looked. If nothing is out yet, in the meantime, something might be gained with stiffer rear swaybar bushings.

 

So you have presented an analysis of the performance differences of these two cars. Cool.
You have to drive around the shortcomings of the C8 chassis like you do the Porsche. Why would you want such a car? What are the shortcomings? Why is there 8' pos caster in the front? Porsche 992s have 9". Why? NSX 3, Lambo Huracanand Audi A 8 has 4 as do F58 and 488s, Why? Why does a C8 require track settings (3' neg camber) etc. and not the above cars? Why did Michelin work with GM engineers to build the C8 tires with a different structure? Gordan Murray used off the shelf tires for his new $2 million super car?
What are the roll centers of your C8? What are the roll couples? What is the longitudinal roll couple? Most important, you have weighed your C8 and have determined the longitudinal location of the CG. What is the vertical location? Why is this important? Why did you not calculate it when the car as on the scales? Tadge said that it is higher than the C7. A few members have supplied corner weights but not the one calculated the vertical axis.
Why is the C8R so different? How is Pratt and Miller's C8R going to be modified to compete in GTD, GT3 and WEC when they are forced to leave GTLM? Heh, how? Complete the analysis please. You will have to in order to set you car for track use.

 

My understanding is that the understeer characteristic is easily tuned out. I've read that GM purposefully built into the suspension, going to the general public, understeer to help prevent naive people getting into trouble. I've read comments that it's easy to negate the understeer characteristic in a stock C8, I forget the specifics. I think it's nothing more than just tuning the sway bars. Once again, I think street cars, sold to the general public, have understeer built into them.

Let's see if I remember this correctly. For the orthodox front engine car, to dramatically achieve oversteer, delete the front sway bar and install a stiff rear sway bar. For the Hollywood action movies, where you want to film a car spinning out, this was the technique for the stunt crew to follow to get dramatic spin out shots.
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I'm not a competition driver. I prefer a little understeer. If I'm making a high speed turn on a freeway exit ramp, I prefer not to see the rear end of my car passing me.