SUSPENDED: IMSA Goodyear North American Championship

The last Miata race is 3/25. The first IMSA NAC race is 4/08.

Right well as far as things go i'm currently in talks about about being bought out of my current contract to join this series. so fingers crossed i can get a factory drive. Any factory teams interested in a driver who is currently leading another north american series, should contact my agent pete burns.

Thanks Snip

This would be ideal for me to pick up some pointers on suspension tuning if I can get a co-driver who is clued up on such things. I can put some time in on other stuff like the livery and tweaking gears, etc. but getting a good base tune is my major headache. Any takers?

BAD BOY69...I'd take you up on that offer, but I'm still learning to tune myself. As far as tuning the springs, this is the formula I use....here is an example worked out.

(weight+downforce) /100 x weight % / ride height x G's

Car stats:

weight- 3009

Front %- 55

Ride height- 6.2 inches

Lateral G's @ 60mph- 0.94

3009 / 100=30.09

30.09 x 55=1654.95

1654.95 / 6.2=266.9

266.9 x 0.94=250.8 this would be your front spring setting. To get the rear, multiply by 45 instead of 55

The weight in this example is from a non aero car. If you have aero, add the downforce to the weight, front for front, rear for rear.

I got this from VVV Worm's Tuning Guide on FM.net.

Thanks for that, I'll give it a go and see if it works for me. Just a couple of points though...1, Downforce-As this has more effect the faster you go, how does it figure on slow corners? i.e. the spring setting would be a higher value, is this favourable for grip in turns? 2, Ride height-Do you run the formula and then adjust it to stop bottoming out and do the formula again? 3, How do you calculate rebound settings?

Perhaps reading the full guide would be a good idea...

Edit-Just noticed Angel's troubleshooting guide. Could just be what I need.

@B4D BOY69...That formula was created for Forza 3 but can sometimes make the springs too soft for Forza 4. I had no problem with too soft springs for the GT500 series, that formula worked perfectly. But I've noticed for the Lotus Endurance car it comes out too soft. In that case VVV Worm said to multiply the final result by 1.5 or even 2. The best thing to do is read his post to get a better idea.

What I do is set the ride height and downforce first, then use that equation to get the spring settings. If any changes to either the ride height or downforce are needed, then you will have to re-do the equation to get the new spring settings. Once the springs are set, I then bring down the bump and rebound a little. That is if the new spring settings are softer than the default.

That formula has been made and used with the best intentions, however it has been made up by someone who hasn't got enough knowledge of physics and as such made several mistakes.

What is correct in the formula: spring stiffness according to the weight distribution of the car. Example, a 1000 lbs car with 55% front weight distribution has 550 lbs resting on the front springs and 450 lbs on the rear springs (small simplification by disregarding unsprung mass which isn't that much). This car should have it's front to rear spring ratio matching the 550/450 balance of the weight distribution. This will give stable springs, where front and rear springs will act the same.

Wrong: applying downforce in the formula. Downforce is displayed in the tuning menu as a constant weight pressing down on the car. In reality, downforce is a variable, increasing along with the car speed. The downforce numbers shown ingame are only applicable for a certain, unknown speed. In slower corners, downforce is negligible. Furthermore, the way downforce works is not the same as the car's mass. In the formula, downforce is a weight that is added to the car's mass and that shifts along with the car's mass during cornering. In reality, downforce doesn't move from one side to the other, but keeps equally divided on the 2 sides. That gives totally different spring reactions.

Ride height: ride height is the ground clearance of the car, and not the mass centre. Forces are applied in the mass centre. Cars with higher mass centres will have higher forces working on the springs when the weight shifts, and as such could require stiffer springs to keep elongations in check. The height of the mass centre is however unrelated to the ride height (imagine a lowered SUV compared to a jacked up Ferrari, the SUV will still have a higher mass centre despite the ride height that could be the same or even favoring the SUV).

Lateral G's: cars with higher G's can shift more weight in cornering, and can require stiffer springs.

What I'd use for springs:
front = k * weight * front weight% / 100
rear = k * weight * (100 - front weight%) / 100
where k = a contant factor found by experimenting

Or simplified:
front = k * front weight%
rear = k * (100 - front weight%)

Othelion wrote:Downforce is displayed in the tuning menu as a constant weight pressing down on the car. In reality, downforce is a variable, increasing along with the car speed.

That was what I was referring to but not quite as well put. How do you find constant k? Telemetry?

Thank you for clearing that up Othelion. I had wondered about the downforce side of things, but didn't have enough knowledge about physics and just took that formula at face value.

I must have got lucky with the GT500 car, coz it felt perfect handling wise...but that formula certainly doesn't work for the Lotus Endurance car....I'll try your formula out, once I get my head around it.

So, Dom are we teaming up? if so, can you please send me tune and paint?

I'm still in need of a teammate.

Schnitzer Motorsport today announced they have added Robert "Bobbo" Thomas to their driver line-up to represent BMW Motorsport in the upcoming IMSA NAC season, teaming with veteran driver Dominic Mako. Bobbo filled in last season for an injured Darrell Waltrip for several races in the 1990 NASCAR Winston Cup season.

Team boss Herbert Schnitzer was quoted as saying "We're aware of Mr. Thomas's history and have done due diligence on our background checks and in interviewing the driver. We feel the talent and determination he brings to the team will be invaluable, and we look forward to a successful season."

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Just great fellas, really well done such a nice looking outfit.

Fun Fact: I wasn't even BORN in 1990

hehe, bobbos also not race number 2 yet

@ Ripped

It would be a pleasure to run with you

well by the time this series starts I'm hoping to be, if not just a quick change from a 2 to a 4 and I'm all happily done

B4D B0Y69 wrote:How do you find constant k? Telemetry?

By experimenting, trial and error. You can get certain things from the telemetry like if the springs are too soft they will go red when you go over a bump. Too stiff the car won't digest bumps well. Other characteristics are too soft and the car will feel slow responding, too stiff the car will respond quick but drives on the edge and slides easier. For a better insight I suggest looking at Angel's comprehensive guide or asking any of the good tuners here.

Moving back to the imsa subject, I will be able to participate in only 3 out of the 5 races. Given that, if anyone is interested in teaming up with me, let me know. A lot of the cars interest me, although I prefer the American cars or the Beemer (anything but Japanese then). They just seem to fit the theme best imo.

Uhmmmm...what to do...what to do. This is all getting very confusing and I don't mean all the tuning and regulation requirements. I'm referring to choosing a running mate for the series. I realize that it wasn't necessary to have a team mate, but seeing as I offered, then it seems only right to go through with it.

B4D BOY69, I'm not sure that I would be of much use to you as we seem to be on an even keel when it comes to tuning knowledge.

Clark, I didn't know if you were still looking for a team mate or not. It would have been cool to run with you.

BlmThug, seeing as you have asked me directly, then I will go with you. Let me know what car you want to use and if it's going to be factory or privateer and I'll start putting a tune together.

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Venezuelan driver Alberto "Johnny" Cecotto took time before his 5th DTM campaign begins to observe winter testing for the new Schnitzer Motorsports BMW team being fielded for the IMSA Goodyear North American Championship. Having raced motorcycles for Yamaha, Formula 1 for Theodore Racing, and recently taking 2nd for BMW in DTM, he has considerable experience. After watching the team's new drivers, Bobbo and Dominic, turn several laps at Road America, Johnny commented "The cars look a little loose. I'm sure the team will work out any struggles they're having with the car still."

The team tried both the harder and softer compound tires. Despite leading the test session, Dominic Mako described the car as "slidey" and expressed concern about consistency. Bobbo also seemed to struggle with rear-end grip, having a couple off-track excersions, but doing no damage to his car. Both had confidence in the M3 powerplant.

The team did not comment on the recent report linking Dominic Mako to an FBI racketeering investigation in the U.S. New England area. Mako's connections to the Patriarca crime family have been called into question as of late, and rumors have surfaced that his cancelled Ecosse Motorsport contract was due to these allegations.

YES>>>> I AM STILL IN NEED OF A TEAMATE.

I don't want to go asking everyone as I am not sure who wants to run.

I would prefer a driver who uses the controller, tuning would be easier.

BMW factory has been taken.

I'll run factory, or privateer.

Please let me know, im itching to beat Bobbo

I will go with a two man Ford factory team with Clark.

Settled:

Slasher and I will be part of the Factory FORD team.

@Ripped

Thanks bro, I suck at tuning. We will be a Privateer team running the 1992 Nissan 240 SX

B4D BOY69, I'm not sure that I would be of much use to you as we seem to be on an even keel when it comes to tuning knowledge.

No worries, Bud. I was thinking along the same lines, as in, what I could offer you as a team-mate. After spending a fair few hours on the Lotus and only knocking about 1.1 - 1.2 sec's off stock, my conclusion would have to be "not much". I think nearly half of that was just sorting the gearing. It still has a tendency to just slide out every now and then and the brakes are bobbins. Too be fair, I think I've cut the sliding issue down to 2 things. It's either the car or me