| Author | Message | ||
| Modified348ts (Modman)
Member Username: Modman Post Number: 584 Registered: 11-2001 |
Wasn't the pic taken while doing the dyno? I remembered seeing this pic before. | ||
| Tuco Ramirez (Tuco)
New member Username: Tuco Post Number: 1 Registered: 5-2003 |
I have noticed this with the 360 when the thrust alignment is a little off. I would recommend you have the toe setings checked on the front and rear. | ||
| arthur chambers (Art355)
Intermediate Member Username: Art355 Post Number: 1687 Registered: 6-2001 |
I wouldn't change the tire sizes, I'd measure the wheelbase, check to make sure that everything is true, check the weights on the corners, the front end dimensions, the rear end dimensions. Then compare those to the service manual numbers. If they all agree, your car should be stable. If they don't agree, you've found the problem. I had that loaner I just gave back up to 135mph, and it felt very, very stable (I'm not saying where I went that fast). Art | ||
| John Delvac (Johndelvac)
Member Username: Johndelvac Post Number: 380 Registered: 11-2001 |
That's not my thumb!  Talk about stimulation - geeezzz. I'm afraid my coffee and latest issuse of FML wouldn't relax me the morning after that drive. Man! | ||
| Nick Yim (Yimn)
New member Username: Yimn Post Number: 35 Registered: 11-2002 |
sport mode. if i change tire to 225/40/18 and 295/40/18, would that help? | ||
| Willis Huang (Willis360)
Intermediate Member Username: Willis360 Post Number: 1248 Registered: 8-2001 |
Were you in sport mode when you were doing this? For me, the car's rock solid at speed in sport mode while there's some steering play in normal mode. | ||
| Mitch Alsup (Mitch_alsup)
Member Username: Mitch_alsup Post Number: 656 Registered: 4-2002 |
In "Race Car Vehicle Dynamics" � Milliken and Milliken ISBN 1-56091-526: The author derives an interesting relationship between high speed stability and steering "feel". It turns out that the more understeer a car has, the less sensitivity the steering has at high speeds. A completely neutral car has linearly increasing steering sensitivity with speed, while a understeering car gains sensitivity into the 120 range then plateaus out as speed increases. So if you wnat to loose the high speed steering sensitivity, you have to dial in more understeer. And like Brad said, you (the driver) have to be faster that the car to avoid Driver induced Oscillations. However, "Things happen exponentialy faster at high speed" is not true. Cubic or 4th order yes, exponential no. Repeat after me, almost nothing is exponential, and there is a big difference between 4th order; or even 10th order; and exponential. Exponential is another 'kind' of range entirely. | ||
| Paul Bianco (Paulie_b)
Junior Member Username: Paulie_b Post Number: 134 Registered: 1-2003 |
Stephen, looks like Franco! He knows me. Tell him I said hello. | ||
| Nick Yim (Yimn)
New member Username: Yimn Post Number: 34 Registered: 11-2002 |
I did that speed in China during the FOC HK china drive. | ||
| Michael Vaughan (Vanimal)
New member Username: Vanimal Post Number: 29 Registered: 3-2003 |
Stephen S...you say the gent in the pic was holding the wheel with his knees, but you can see his thumb on the left of the steering wheel?? or where you refering to another picture?? | ||
| Ming Cheng (Onlinesys)
Member Username: Onlinesys Post Number: 281 Registered: 5-2002 |
Hi Nick, Sorry to hear about the dealer problem. You should contact the chief service manager of IM in HK so that you could show him in person the problem you encountered. Driving at 280km in HK? I am impressed! | ||
| Nick Yim (Yimn)
New member Username: Yimn Post Number: 33 Registered: 11-2002 |
Thanks for all the comment. I can't agree with Dr. Shelbee more. I have a 550 as well and the car just feels the same at 100km or 280km. I am not saying the 360 is not stable but asking for ideas from you as to what I should check. I am pretty sure there is something that is not right with my car and just don;t know what. The dealer is not super helpful either.` | ||
| Dr. Shelbee (Shelbee)
Member Username: Shelbee Post Number: 301 Registered: 12-2002 |
Nick, I feel more comfortable at the higher speed on the Maranello rather than 360. 360 feels better in the cornering but need careful attention in higher speed | ||
| Stephen S. Saia (Sssaia)
New member Username: Sssaia Post Number: 21 Registered: 4-2003 |
 This gentleman (some of you may know him) held the steering wheels with his knees and snapped this pic on the interstate late at night. Yes, this pic is real, the real one is hanging on the wall at No Problem Raceway in Louisiana. | ||
| Steven J. Solomon (Solly)
Member Username: Solly Post Number: 472 Registered: 6-2001 |
I've had my 360 spyder up to 170 at Pocono, steady as a rock. No problems on street (highway) at 100+ mph late at night either. Tire pressures CRITICAL for good handling. Definitely get it checked out, something is wrong. | ||
| J.D. Smythe (Jeff)
Junior Member Username: Jeff Post Number: 181 Registered: 2-2001 |
Yimm I've had my 360 spider at 150 mph on numerous occasions. Everyone who was riding passenger commented on how "solid" the car felt at speed. | ||
| Brad-Mo (007)
Junior Member Username: 007 Post Number: 58 Registered: 2-2003 |
The road surface plays a big part in how a car feels at high speed (100+ mph). Even the best 200+ top speed autos in race trim feel darty and unsettled at these speeds on anything less than smooth surfaces. Even smmoth roads with many dips, even shallow ones, will upset the car as the air gets under the car as the suspension unloads at the top of the hill, giving a light and unsettled feel. If it is a pulsing or vibration, tires, wheels and suspension should be checked. don't forget that a VERY light touch is needed at speed. Things happen exponentialy faster at high speed, an appropriate input at 80 will be scary (or even dangerous) at 120. This brings up DIO or driver induced occliation, the input of steering commands to null unwanted motions become a faster and faster until the driver cant stay ahead, once you get behind the car at the least you'll have a darty and unsettled ride or you could bend the machine or possibly the driver. Be Careful! Driving at high speeds even in a straight line is a challenging thing to master. | ||
| john (Johnwto)
Junior Member Username: Johnwto Post Number: 87 Registered: 6-2002 |
what do you consider high speed? | ||
| Raymond A. Castelhano (Oglmlw)
New member Username: Oglmlw Post Number: 11 Registered: 5-2003 |
Hi Nick, I would have the tires checked to be sure they are perfectly round. If that proves fruitless, you should send the shocks out to be tested. Find a race car builder and ask where they have shocks tested. The tester should send back a report (usually with graphs) on each shock. Just be very sure you mark them well before you send them. MrC | ||
| Nick Yim (Yimn)
New member Username: Yimn Post Number: 32 Registered: 11-2002 |
My 2001 360 does not feel very stable at high speed. I feel the tires do not have full contact with the road and the steering is not smooth either. I have checked tire pressure and done a wheel alignment. Did not help much. Anyone has any idea what I should check next. |