Test-N-Tune comming up Options

[Toecutter]

I have a Test-N-Tune on June 9th, I wan to try at least two things.

1) Disconnect front swaybar

2) Play with damper settings
(a couple of runs at Min vs. Max to see if I can tell the difference)

Front is -3 degrees and 1/8" toe-out. The rear is -1.5 degrees and 0 toe.

What I have listed above is probably all that I'll have tome for, but I'm open to additional suggestions.

[SWortham]

Tune with tire pressures...

A given tire on a given car on a given surface will have a sweet spot for the ideal pressure.  With an understeering car, your goal should be to maximize front end grip above all else.  So your first step should be to find the ideal pressure for the front tires. 

If you're an autocrosser, then perhaps the best opportunity you'll have to do this would be at a local test & tune day since it's common to expect a skidpad at these events.  You could use a GTech or some sort of accelerometer if you want to get fancy.  Or you could simply test grip by having a buddy time you around the skidpad, change the front pressures, and test again.  Once you find the front pressures that give you the most grip, then you can leave them as is and simply change the rear pressures to tune out a handling bias.  Increasing the pressures beyond 40 or 45 psi in the rear could decrease grip enough to give you that little bit of oversteer upon turn-in that's so helpful in autocrossing.  You certainly don't want to go crazy in trying to achieve oversteer but a little bit helps.  And no matter what, a FWD car will still understeer on throttle so don't worry about oversteer on corner exit.

Just remember that once you change your suspension, or change your alignment, or especially if you change tires, that these ideal pressures that you found probably won't be the ideal pressures anymore.  So you'll have to go through this process again.

Happy tuning.

http://www.elantraclub.com/forum/index.php?showtopic=15372



This post has been edited by SWortham: May 31 2007, 04:38 PM

[silet]

1) Disconnect front swaybar

Let us know what happens, please???

[oiml8]

I would like to know as well but from what I've heard it is mostly the honda guys doing that. Their swaybar is like 12mm. Ours is 24mm (?) Also I believe it would cause way too much body roll which will decrease traction on the outside tire. I am speculating but that is the reason I have not tried it. As for tire pressures if you race on the same track or have multiple years running the same tire on different tracks, you can catalog your pressures and set them accordingly. However, that requires a lot of pre planning. I measure my tire temps to try and keep them hot on the outside, less hot in the middle and cooler on the inside. Idealy they would be the same temp all the way across but you are usually in some sort of turn during the entire course so that is unrealistic.

You may find that seriously over inflating your azenis is the way to get the rear end to come around more easily and predictably. I'm talking 50-55-60psi. I went the opposite way with the bfg's and had to go all the way down to 20psi before it felt loose. That was on airport concrete (portland) tho.

I would also put the rear camber to 0

[Toecutter]

The Test-N-Tune was money well spent. I got about 40 runs, 6 or 7 of them in a really fast '91 Civic Si Hatch (which I spun).

I also had one of the more seasoned drivers drive my car to get his impressions. He said that my car had more power than his Honda, and does everything well except turn-in. He said that the turn-in was pitifully slow, but that is the only area that my car needs help in. After driving his car I now know what quick turn-in is like.

He suggested that I disconnect the front swaybar, which I was planning to try anyway. I found that this produces way too much body roll for my liking. I think that there could be a happy medium with a smaller bar. Does anyone know if the front bar for the GLS is any smaller? I think that a smaller bar up front could provide better bite, but still control roll. Is there anything else that I can try to help turn-in?

I found tire pressures that seem to work pretty well. For fun, I bumped the rear tire pressure WAY up. With the rear tires running at 50 psi, I lost control on the last cone of a slalom and spun it... killing a few cones along the way. Anyway, I started laughing out loud and the course workers were lookin at me like WTF? I then shouted out the window "I finally found some oversteer"! They smiled back knowing exactly what I was talking about. However, it was not good oversteer. The Falkens didn't give me any warning that they were about to break loose at that pressure. I get a lot better feedback from the rear tires at 36 psi.

Later in the day, and through a lot of patient instruction from a veteran driver, I am now able to produce oversteer on demand and pretty consistently via throttle lift and trail braking. I still think that I want to try the Whiteline bar in the rear to see what happens.

Finally, I did have an accelerometer in my car for the Test-N-Tune. They Elantra holds 1.04G, which really isn't too shabby for a car on street tires (RT-615s).

Again it was nice to get some pointers from a really good driver, this and the tremendous amount of seat-time was extremely helpful. Kinda like a mini impromptu driver's school.

[Bobzilla]

Wow! 1.04g is VERY impressive! I wish we had a test-n-tune. But when you get 100+ cars show up it makes it a wee-bit difficult!

Yes, the GLS front bar is 1mm smaller. What offset are your wheels?

[Toecutter]

The wheels are 15" x 7" with a 40mm offset. I'd like to have 45mm or better, but can't afford a new set of wheels right now. Front toe-out is 1/8"... don't think I want to go with more than that. I set front dampers all the way soft, and that seems to have helped, but only a very little bit. Lowering tire pressures in front didn't help at all.

I've been told that the caster is not adjustable on the Elantra. Is this true?

[Bobzilla]

Correct. . . mostly. I mean you could go wild with a complete one-off suspension setup, but that would move you into big money classes

The 40mm offset should give a little better inital response than the 45mm IIRC.

[Toecutter]

Correct. . . mostly. I mean you could go wild with a complete one-off suspension setup, but that would move you into big money classes

Yeah... that ain't gonna happen.

If the GLS front bar is only 1mm diameter smaller, then I don't imagine that it's going to be much help. Furthermore, I think that it would be a mistake to upgrade to poly bushings up front.

Another suggestion that I have gotten is to loosen the front endlinks. This would allow the car to turn-in before starting to load the swaybar. I don't know if I like this idea... something about loose nuts bothers me.

Maybe, I need to just try the Whiteline rear bar to see what happens.

[cobas]

Sounds like a blast and you're going to be teaching other members here a lot. There's no way that was sustained 1.04g, though. Just no way.

[Toecutter]

There's no way that was sustained 1.04g, though. smile.gif Just no way.

OK, let me restate that. We didn't have a proper skidpad, so you may be correct. The accelerometer was set up to record peak g-force. So I was incorrect in stating that my car held 1.04g. It did however attain a peak of 1.04g.

Whiteline says that an increase to 22mm from my current 19mm in the rear will provide an 80% increase in stiffness. I would probably buy the 22mm bar because it's cheaper than the adjustable, and I have the 19mm to fall back on if it's too stiff. Any thoughts?

[Toecutter]

OK, it didn't take me too long to decide. I've ordered the Whiteline 22mm sway bar (P/N: BHR68) from TurboWholesale.com

It came to $139.00 including shipping.