Problems with tracking the Challenge Stradale

The Challenge Stradale understeers a lot on the track and is much less steerable by throttle than the 360.

1. Can understeer be slightly reduced by changing the alignment, and if so, by how much?

2. There is no track tire for the CS. Do the 430 Challenge race tires fit the CS stock wheels? Do they have the same outside diameter and do they fit the wheel wheels?

At Laguna Seca, what is the best possible time for the CS without slowing down for sound check?

 

1 - what mode is the suspension setting you are using on the track?

2 - You can use the 360 challenge stradle wheels with slicks

Pirelli front size - 235/645-19

Pirelli rear size - 295/680 -19

Bob woodman tires can get them for you.

www.bobwoodmantires.com

best regards, Jim

 

Thanks Jim.

Race mode was used and ASR was on.

The race tires are 10 mm wider than street tires. Is that OK?

Are there any phyical problems with using slicks on the street besides wet performance?

 

PM me... I have a good friend who can help you with your setup, plus make your CS "sound legal" for Laguna Seca without having to sacrifice lifting or going slow past the sound booth. The CS's he has done have a street/track alignment setup that makes the car fairly neutral. He can also help you get the proper tire setup on there for tracking your CS.

- Robbie

 

Mine doesn't understeer at all, it's very neutral.
Get an alignment, go to -2 degrees camber (stock is -1.5). Set tire pressures to 30 cold, 38 hot.

 

Thanks for the camber suggestion.

30 psi in front and 29 in back?

 

Never experinced understeer. Are your tires ok ? You know that you have to adjust pressure after a few laps ?

To many laps without adjusting pressure will get you slippery tires and that could maybe give understeer ?
You can´t powersteer a car with ASR on in race mode.

In this case it sounds like you ehave to high speed entering the corner... =)

 

Gentlemen, cars don't understeer by themselves and, as I've learned, it's often a common complaint from so-called 'automotive journalists'.

 

? Maybe the CS doesn't, I don't know, however cars do understeer by themselves if the suspension is dialed in to do so. I used to have a Crossfire ST6 that had slight understeer from the factory but I took care of that pretty quick and had it set to neutral with slight oversteer. I've heard plenty of race car drivers complain of it on new cars for their first tests.

 

All street cars, even the CS, have "understeer" dialed in the car to make sure the owners don't crash them. You can easily take out the understeer with a more aggressive alignment. I've driven the CS and Scuderia, both understeer on the race track. I've also driven a F430 with a more aggressive track setup and it was much more neutral with slight oversteer.

 

I'd have to agree. Unless I'm entering the corner too hot the car is perfectly neutral. I'm not a race car driver (and didn't sleep at the Holiday Inn last night), and am running street rubber.

Jack - will you be at FCA's Ferrari and Friends track day at Thunderhill?

 

The 360 I had before the CS seemed more neutral. Oversteer could be provoked by lifting mid turn. However the CS definitely understeers more in comparison, and much less sensitive to lifting. Maybe this difference in perception is due to the fact that I now drive the CS harder and a full 10 seconds faster than the 360 around Laguna Seca. I don't know.

I set the tire pressure to factory recommended cold and leave it. The tires understeer a lot when new and less when worn.

Entering a turn with trail braking gets the tail out but adding power brings in understeer again.

Ni - my next track day is probably July 19 at Laguna Seca. Will you be there?

 

Not adjusting pressure will give VERY high pressure and bad grip from your tires.

I don´t know how experinced you are at track, but understeer is a fact when entering a turn at wrong speed/ line. The car does not make mistakes, driver do.

When driving as I should, I find the CS very balanced.

 

Should it be 38 psi (2.58 bar) hot?

The CS is more balanced on the higher speed turns but understeers on the slower turns at around 40 mph (70 kph). How should the slower turns be driven to avoid understeer?

 

cars do understeer and oversteer "by themselves".

it's a common complaint because "journalists" review street cars and virtually all street cars are setup to understeer.

 

All 360 and 430 including Challenge race cars understeer. 360 and 430 GT2 cars solve that problem with 35mm wider tires and track per corner at the front.

You can try a bit more camber at the front as suggested by others. You can also try 1mm to 2mm toe out at the front to get better turn in at slow speed corners. If you use slicks then try 3 to 3.5degree camber at the front and 2.5 to 3 degrees camber at the rear. Be ware slicks will likely destroy your rubber A-arm bushings fairly quickly as they not not designed to take the load generated by slicks.

If you have access to a tire temperature gauge check your tire temperature profile. Inside edge should be the hottest while outside edge should be the coolest. That will give you some indication if your camber settings are correct or not.

BTW if your tires are more than 2 years old, they are way past their prime.

 

No, they don't.

What's your car doing while you're in front of your computer looking at this forum?

 

please. clearly your meaning was that understeer is an error on the driver's part.

 

Well partly it is. Understeer is when the front tires looses grip when turning and tha car goes straight on. Why does it do that ?

You try to force the car into a corner to fast. When braking correctly and turn in at a "correct" speed the CS is very balanced. If it is not, check your tires condition and pressure. With Pirelli corsas you get overheated tires quite quickly and the car feels slippery.

 

It most certainly is. Cars don't understeer on their own. You and I can mitigate understeer through the usual techniques, but this is always a challenge for novices.

The myriad track and vehicle variables change from one session to the next, often within the same session, let alone from morning to afternoon and, as such, drivers, particularly novices in road cars, must learn to remedy understeer (and oversteer) first before going to set up changes.

For the record, so-called 'automotive journalists' whine about understeer because, well, they all think they know what they're doing.

 

Lucky all the race engineers don't know that or else they'd be out of a job.

 

This is not a racing thread.

 

Touché. However OP is referring to on track car behavior. Assuming he is a fairly competent driver, it's simply not true to say any road going 360 or 430 does not understeer. As wonderful as they are, they do understeer in the sense the rear has more traction than the front in both low speed and high speed corners. Driving techniques such as trail braking, throttle lift induced oversteer, power slide on exit, or simply lower entry speed can mitigate the understeering characteristic of these cars but fundamentally the understeer tendency is still there.

 

That's an awfully big assumption.

Any reasonably skilled driver can make any car understeer, intentionally or otherwise.

 

The Scuderia understeers in excess. I have the stock alignment specs for both the Scuderia and Stradale, and the Stradale should understeer a lot.

Sping rates are too soft, I have pictures showing over 4" of suspension travel. The fix is cheap and easy: new springs, new sway bars, new alignment, and better tires.

I will be testing the Toyo R888 next weekend. I liked this tire in my Boxster Spec Racer. The stock Pirelli Corsa are the worse race compound tires I have driven.