Chaparral 2j vacuum cleaner car

[SirBerra]

I had to purchase the 2J since I had watched it race in the US Can-Am series many years back. In some ways this car is a dream to race, but there are some handling quirks I just can't figure out. In the GT4 American Races races this car easily beat all the competition by 20 seconds or so in all races. This car literally flew away from the Audi Race Car at the Tsukuba Hard Wet Race in Special Conditions. However....
This car exhibits a fair amount of wanting to swap ends under high speed braking or in some cases actually swapping ends while going down straights under full power. Kinks in any straight seem to cause instability. Going down Mulsanne when the ground gets a bit bumpy is really scary. The car starts to squirm horribly and then goes into a spin. I have even noticed this in the Seattle race on the downhill kinked straight toward the back of the course. The wheelbase really looks short so that may be one reason. Another is that it is very low to the ground and the suspension may be bottoming out under certain conditions.

I intend to spend a few hours experimenting with the suspension and such. I'm unable to figure out how to set toe-out because I don't know which way is positive or negative for toe-in or toe-out. This group seems to point out confusion over that setting also. I'll just have to experiment to see what works. I'm going to also raise the vehicle clearance to see if bottoming out is causing problems.

I really would like to use this car and I'd swear it would be the perfect car if not for some bizarre handling behavior that hopefully just needs to be sorted out. If anyone else has any suggestions or found any solutions, please post them.

 

[SirBerra]

Arguably one of the most intriguing cars in the GT4 line-up and probably the only "reverse hovercraft" ever built. The fact that the auxiliary Rockwell snowmobile motor generated 1500 lbs of downforce, enough to hold it upside down on the ceiling (remember the fans on the back?) and Polyphonys faithful reproduction of this unique trait, make an aerodynamic wing (also innovated by this cars inventor) quite extraneous and suspension tuning completely exasperating. Built with secret Chevy R/D support and killed by the McLaren pressured SCCA because its lexan skirts "violated" the moveable aerodynamics rule; it would have revolutionized Can-Am Racing by raising cornering speeds to new and dangerous (at the time) heights.
This tune allowed my modest skills to win the American Championship. At the end of the first lap at El Cap. I easily had a 5 second lead on the next fastest car, the Esperante. The car has had all modifications including roll cage/rigidity upgrade. Tuning was done with matched racing tires, usually mediums. The tranny tops around 160 so, add auto if needed. i recommend the stage 3, lag for the stage 4 will have you tearing your hair out.
(remember the downforce, luke, this car stops fine and has good brake steering)
brakes 5/22
springs 13.4/10.6
height 70/70
bound 9/5
rebound 9/5
camber .6/.9
toe -1/0
stablizer 2/5
auto 10
asm 0
asu 0
tcs 3
lsd 45/15/23
weight 200/-50
enjoy!

Sorry, but these settings still don't really work for me regarding stability. I am curious how you arrived at those settings. Did you do it through experimentation or get those settings from theory or what? Think maybe Jim Hall has a web page somewhere? Is he even still alive? Anyway. Whenever I brake at high speed the nose just continues to wander about. It's feels like the rear end is lifting and losing traction. How perplexing.

 

[siliconcenturio]

Sorry, but these settings still don't really work for me regarding stability. I am curious how you arrived at those settings. Did you do it through experimentation or get those settings from theory or what? Think maybe Jim Hall has a web page somewhere? Is he even still alive? Anyway. Whenever I brake at high speed the nose just continues to wander about. It's feels like the rear end is lifting and losing traction. How perplexing.

my advice, dont install the rigidity update. at very high speeds in this car it makes it completely unstable. just to test i bought ANOTHER one and didnt install the rigitidty thing and it was MUCH better

 

[boost654]

dont forget the brabham F1 car; one of few cars to beat schumacher i think it was either late 70's or early 80's

Sorry to laugh but, ugly as he is, surely you dont think Schumacher is that old!!

 

[rk]

I'm going to also raise the vehicle clearance to see if bottoming out is causing problems.

I really would like to use this car and I'd swear it would be the perfect car if not for some bizarre handling behavior that hopefully just needs to be sorted out. If anyone else has any suggestions or found any solutions, please post them.

Remember this car represents an active ground effects vehicle. As such there is a definate loss of "suction" as you incrementally raise the clearance, however, 20mm over minimum was required to establish my updated tune which turned 1'06.291 at Deep Forest on racing hards. Anything lower was clearly bottoming and darting about.
Please check the original post since I will have edited it with this recent tune.

 

[SirBerra]

my advice, dont install the rigidity update. at very high speeds in this car it makes it completely unstable. just to test i bought ANOTHER one and didnt install the rigitidty thing and it was MUCH better

Thanks for the tip. I'll try anything. Heck. It doesn't figure why a more flexible car would handle better. I'm already tearing my hair out after trying so many settings variables. I was able to run 0:56.9 at Midfield Normal, but not consistently. Hard braking completely de-stabilizes the car. Soon as I tested it again on Sarthe's main straight at 235 mph, it was spin city.

Ultimately this will not be my main car for racing (I'm partial to the Toyota GT-One), but I'm so intrigued that I can't put it down and I'm probably wasting my time looking for magic.

Sir Berra

 

[Hondaguy]

Here is a fact about the 2J that no one has mentioned. The 2J was equipped with a 3 speed automatic transmission. Anyone notice that GT4 doesn't tell you when to shift the 2J? Jim Hall equipped all the Can-Am and world endurance racing Chaparral's with a 3 speed automatic that he developed. He figured shifting was one less thing the driver would have to do.

Here is a link to a page with all the specs on the 2J

http://www.mulsannescorner.com/chaparral2j.html

 

[2005mustang]

i GOT THIS CAR TO GO ALMOST 200 MPH IN REVERSE!! IT'S TRUE! ALL YOU DO IS MAKE ALL OF THE GEARS AS WIDE AS POSSIBLE (the auto and final too) Go on test course and try it

Please try it, I know you think it is impossible but I did it and it works!

 

[ChiaChase]

To enhance the stability of the 2J when braking raise the strength of the LSD under deceleration A LOT. I mean like jack it all the way up to 60. This helps control the rear end when braking without effecting the cars awesome ability to turn in sharply while braking. If you still want it to be more surefooted under braking, increase the front brake balance in addition, or do a little bit of both. I have yet to mess with the suspension much but i doubt you can keep the car from literally flying out of control over elevation changes because the second the car lifts up you loose all down force and only way to prevent that is to increase down force (which can't be done on this car). It might be possible to keep the car more settled over small bumps by lowwer shock bound and maybe raising rebound but i haven't tryied it.

 

[BLARKEEKSNARK]

Does anyone know which Chapparal car is better? i really really want to buy one, but im not sure which one to buy. I think im going to get the 2j because of the looks but does anyone have an opinion on this?

Buy 'em both. It only takes about 40 minutes to earn a cool million via the Special Conditions Events, TC Tsukuba Circuit, ib race. But that, of course, I'm in the normal mode. Maybe you're out of my league and the earning rules are a bit more stringent where you race.

 

[eSPy]

i know this might be a bit n00bish, but is this car only in the NA release of GT4? cuz i cant find in anywhere in my chinese version.

 

[KaffeinE 86]

Do you have to buy the 2J? I have the 2D and it isn't that great. It's really light, but it doesn't handle like it unless it's cambered until it doesn't brake. Then I get to complain about it's braking habits...

 

[johnathana]

I am such an idiot. i thought the two things on the back were jets or something. it is a awesome car, and i love it! i have bought all that i can for it, and it is fast!!! in my first race using it, i nearly lost when i spunout. i was hardly used to it.

im 21.7 %

 

[Speedy Samurai]

i know this might be a bit n00bish, but is this car only in the NA release of GT4? cuz i cant find in anywhere in my chinese version.

It is not in the chinese version or the japanese version. It is, however, in the korean version.

 

[djaft3rb3ats]

can anyone pm me or sumtin on where to get the 2j car?