in my opinion, ABS is very much an advantage at autoX, as the surfaces are generally flat, and current ABS includes brake distribution etc. which pretty much does away with dangerous "no braking" under extreme cornering loads with older ABS systems. i would say with current ABS, it is definitely a large factor in a lot of my good times for a day, because i can late brake much more aggressively, knowing i wont lock up the front end and lose steering..

as far as left foot braking, i have done a little, but i've found, to plant an inside front tire during hard cornering, a bit of ebrake (not enough to lock the rear) tends to pull the inside tire back to the ground. it does slow you down, yes, but it also keeps the car more level. this may be different on your suspension setup, but the xA/B has trailing arm, so the rear actually squats with ebrake application.

 

Yeah, I've heard the argument before, but the bottom line is that you really can't beat a good ABS system. There are those purists out there that claim that disengaging ABS gives them more control and whatnot. I can see the argument, as poor ABS systems can work unpredictably or make a distracting "pedal pulsing". But the fact of the matter is, a good ABS system is superior. ABS allows the maximum amount of braking force to be applied without allowing the tires to skid, thus leaving the vehicle in full control of the driver.

 

^
Actually, i've seen countless times at events non-abs cars will destroy a well pronouned abs car. Part is driver, but two of the drivers specifically were very close to knowledge and experience. It depends on what you know in terms of how to control a non-abs car. Its hardler than a good abs system, i agree. But its not impossible to assume a non-abs car is worse for the track environment.

 

There are pros and cons to everything and then different levels of performance a car is being taken to and different levels of driver performance. There is no such simple answer as one is better than the other, far to many variables.

In our particular case, the car is mainly for autocross and longer track type events, street time will mostly be just going to events and back. We will have all out sticky tires, major upgrades far beyond just bolt ons for all performance aspects and I have a fair amount of experience in pretty fast autocrossing, etc.

But, I want to do what is best so I am asking real experts, like the Bilstein Engineer I know that has won many national titles in autocrossing and in very fast cars and not so fast cars. He is one of the best drivers I have ever watched.

After I let him know what we are doing, he advised removing the ABS, said it would be a major hinderance to our particular situation.

I am still asking a few more though, this is a major step but one I could reverse easily and was going to run a few more times before taking it out but now it seems I am just going to do it and be done with it

For most drivers in most situations it may be best to keep it, in our case, it is looking like it should be removed.

Almost forgot, I asked another several time national champ autocrosser that has ran quite a few rallies and hillclimbs and he said to take it out as well.

These are not general knowledge people, these are real experts with real world experience;)

Rick

 

Personally, i say remove the abs if only you think you could feel comfortable enough to handle the car to potential without it. There is no simple answer, but thats the thing that i like. Simple gets old.

 

Agreed and this is the only ABS car I have ever owned, I will have 38 years of driving experience on my Birthday in May and ALOT of it having fun, too much once in awhile though, lol!

Agreed again, we could of hired somebody to build our turbo kit and I did not want a log manifold. We are in the middle of building a nearly(will give up just a bit of perfect lenght to have better asthetics if required) with firing order sequence(becuase it is interesting to think about and figure out) very difficult manifold.

And we are not using an external wastegate because I do not believe they offer enough benifit to hassle ratio, add more weight, more bling we do not really need, etc.

I chose the EVO III GT for the great performance it has proven, compact size, good wastegate design, low cost, etc.

It is about priorities, doing things your own way, research, implementation, testing, making changes, the challenge of going your own way, this to me is what modding a car is all about, not just buying what everone else buys, doing what everyone else does, etc

Rick

 

Given your background, i would strongly suggest throwing abs out the window. I've owned one abs and one non abs. So with that little experience of both i can't really say which i perfer. I do know the xb has done well and i don't believe relying on abs is the reason.

I agree that doing things your own way is much more rewarding. Not to say buying popular parts can't help, i mean majority of parts i have on the box currently others have. But thats not why i bought them, i bought them because i trusted them to get me where i was going..and previous experiences with that company. I have a basic set up, i'm at a dead point right now because the rest of my plans will have to be either custom, or just highly expensive.

Don't do something because someone else does and works for them, do what works for you because in the end its your car and you have to live with that.

 

Alright, I have to ask. This is for killerxromances, and I suppose raamaudio as well.

How are you determining where the center of gravity of your vehicles are? I know the distance between roll center and COG is important, and I know that it is fairly easy to determine where the COG lay on a horizontal plane (eg crossweighting etc.) but it seems very difficult or impossible to determine how high the COG actually lay (ie. where the COG is on the vertical plane.)

killerxromances, you've pretty much stated as fact that the xB isn't "top heavy". Are you saying this based on the fact that it doesn't tip over? or do you have some kind of measurement technique I'm not privvy to? I know many suv's are topheavy and the manufacturer purposfully reduces their cornering ability so they don't tip. At least they did before that explorer fiasco.

Rick, you stated here (or elswhere, I've been reading alot of your threads) that you've lowered the center of gravity of your vehicle. Are you saying this based on the fact that you've removed the glass roof (weight up high), but you don't know exactally where the COG is (on the vertical plane anyways.)

I'm not trying to be a dick, I'm just curious if you guys know some method for determining the hight of COG that I don't know.

 

Well first of all, the xb isn't top heavy because..well, its not. The only major weight thats remote to the top is the glass, which every car the glass is in the same place. The only difference with the xb and say a civic, is the fact the xb looks like a box so people assume that makes all the difference. Not to mention the head room is more than the average car.

I'm not saying the top isn't heavy, but its no more heavy than the average car. The tC, is obviously top heavy because there is a ton of weight in glass alone with the tC. Its pretty much common sense, you don't have to be a genious in math to figure this out.

Also, truly top heavy cars are prone to roll over. I'm not sure which suv's you are talking about that can handle well without rolling over, but the xb isn't even a suv. It's more of a 4door hatch or mini-wagon than a suv. The replacement on the other hand, is more of a suv/crap. Sorry, off topic.

As for COG, i think raam could explain that better than i could. I'm not the best at explaining things like this. Although, i will admit, i can't pin point down to the very last .000000 of COG. Infact, you may know as much as me about measuring it.

 

Here's a simple yet difficult way to deterine the COG:

Staticly balance the car on two wheels--left side or right side (that's the hard part)

The COG will be directly over the point where the wheels touch the ground!

Seriously, there may be an easy way with scales by parking the car (and scales) on an angle and recording the difference in weight left to right in relation to the angle. The steeper the angle, the more accurate the calculation.

(Sorry about that: I have a degree in physics and sometimes I can't help myself.)

 

Of course, you'll have to balance it along 3 different axes to find the actual point of COG, but the plane of bilateral symmetry will be a close approximation for one of those 3, and the front to rear weight bias may offer insight into a second.

 

Fmod, good ideas buddy, there is a more precise way but:

Damm, I just lost a great(at least to me writeup about getting the true center of gravity.

I am to worn out to rewrite it and my son is waiting to watch a movie I promised to watch with him.

After that I have a bunch more business emails before I can hit the sack so will see about writing it over tomorrow

Rick

 

According to SCC, COG is usually around crankshaft height in front and at floor level in back. To calculate actual you have to jack the car up while on corner scales and then plug results into a formula.

 

Yep, what I was going to say as well, we are just waiting to have all the weight located properly in the car first. And my big **** has to be in there as well, maybe I should stop drinking great micro brews and lose 20 lbs first though, lol!

Rick

 

The answer I was looking for, thanks!

FModFTD: there are some great articles I have bookmarked written by a physics guy about car dynamics. I'll have to dig em up for you, I think you'd appreciate all the math.

killerxromances, it sounds to me like you are guessing about the dynamics on the xB more than anything. My last ride was a wrx, and the wagons had very different handling charactistics than the sedan I had. I think you may be underestimating the effect of alot of the subtle differences between the xB and the tC, other than the sunroof. The B is a completely different beast even when excluding the shape of the body. Take the hight of the seats for example. The location of the motor. Obviously the b isn't "top heavy" but I think the COG may sit higher than you think. I'd love to share and auto-x course sometime.

All you physics guys: Which is more important the hight of the COG or the difference in height between the COG and the roll-center?

Thanks for the well-spoken responses.

 

who cares about the car's center of gravity? get coilovers, a good corner balance, and you're good to go.

 

All I can tell you is where to find it. Sport Compact Car August 2005 I never knew when I received it-that this "over the top" suspension info might actually come in handy. I'm still a noob tho-just beginning to understand this stuff. Highly detailed-way more than just throw on a set of coilovers. Here's their part 1 article:
http://sportcompactcarweb.com/tech/0506scc_suspension/
I'm not sure why the rest is unavailable.
THANKS FOR THE SUPPORT! Its highly insulting hearing a kid in a box talking the tc down. I would argue with em if I had any facts to argue with. Although his "facts" really don't prove anything-He's probably just a more talented driver with a better setup than the tc's he has raced.

 

Actually I was thinking more along the lines of this series of articles. http://www.dewtronics.com/tutorials/phor/index.html but thanks for the link.

 

all i know is.. my FSP prepared xA with no engine work whatsoever walks all over STS prepped (and even the supercharged SM) tC's...

the car pushes like woman in labor. . . then again, get a competent person behind the wheel, with proper suspension setup (i.e. race tires, camber, rear swaybar) and maybe the tC can hang..

then again, my car beats vipers and porsches with mediocre drivers..

 

go read some more dude. you can do quite a bit.. you can bore over for one.. but no cam..

clutch and flywheel are legal..
engine management (including upped boost if you have a turbo/sc car) are now legal