SALEEN S7R- lateral load 2,6 G

[lemanfan]

Hey!
I have just read in AUTO-MOTOR-SPORT magazine that 2,6 G is maximal lateral acceleration of Saleen S7R and this data comes from
Konrad motorsport.
I´m very surprising to see so big number and it tell you about high downforce which this car produse.

[Chucky]

That number sounds a bit theoretical, I doubt that they'd see over 2G in the real world.

[RacingManiac]

Transient for a fraction of a sec is very likely.....F1 car don't pull 4 G sustained....

[lemanfan]

It could be in very fast corner which is taken at least at 250 kph.
If we take that the car generate at this speed just over 1000 kg
of downforce and tire can generate at this vertical load 1,4 frictin force
yeas it is possible!
There is only one such a corner in Fia GT calendar and it is Blanchimont
in Spa-Francorchamps.

[Chucky]

Where did you get your downforce figure from? What's a ballpark L/D ratio for a GT1 car these days?

[lemanfan]

Downforce is based on manifacture data that says that the car can run
up side down at 260 kph that mean 1250kg@260 kph!
Yeas it is hard to believe but I just want to find conditions at which can car produce 2,6 G of lateral load!

[ff s conscience]

We can get around 2.2 from Ferrari 360 N-GT on 2002 spec tyres, so I don't think 2.6 is unrealistic at all, considering it's tyre sizes and downforce.

I haven't noted the 550 lateral max, I'll see.....

[SALEEN S7R]

Will be intresting to see what exactly the 550 does produce, Id bet it was a bit less than the Saleen though...

[RacingManiac]

Originally posted by SALEEN S7R
Will be intresting to see what exactly the 550 does produce, Id bet it was a bit less than the Saleen though...

No Saleen is running on Michelin though right? That's easily .2-.4 G right there.....

[SALEEN S7R]

I didnt mean because of the tyres, I just meant purley on the cars design and the cars areodynamics. Get a Prodrive Ferrari 550 and a Konrad Saleen, both on identical rubber and I bet the Saleen has more downforce than the 550.

[marcush.]

I don´t think the Saleen is very efficient in terms of aero.
Looking at the fact how many times they lost their rear
bodywork,there seems to be some cosiderable lift forces somewhere..I did spot from an elevated point at the spa circuit on the run down to eau rouge a pronounced chatter
of the bodywork just under the rear wing ,indicating unstable aeroforces...
I doubt this car has ever seen serious moving grouznd windtunnel work in that configuration

[Bramzel]

You're wrong there marcush. For our game (GTR -> FIAGT computergame) we've had detailed information from Graham Nash about the Saleens, plus the information our physics-programmer has from his contacts in the American motorsport, and the both of them indicate that the Saleen indeed produces a awefull lot of downforce.

[Kid Prozac]

Originally posted by marcush.

I doubt this car has ever seen serious moving grouznd windtunnel work in that configuration

I have had this picture on my computer for a long time now, unfortunately the site i got it off has been removed. If anyone knows the opyright owner, forward it to me and I'll give credit here

[marcush.]

Ok ,ok ...sorry for me being mislead by what I saw ...it definitevely has seen a tunnel...but just why is that nasty things going on under the rear wing then? It cannot be a good thing for downforce or driver confidence and car stability to have the rear bodywork oscillating as much as an estimated 2-3 inches when blasting down a hill and eau rouge approaches....
From what i have learned letting things oscillate at such amplitudes surely will lead to big time failures.
Or did I only think I saw those oscillations...?

[Bramzel]

Oscillations in the bodywork don't say too much. Of course too much isn't good, but don't forget that these bodies are made of ultrathin carbon so it's not too surprizing that it shakes a bit. Also, if those oscillations were too heavy, we'd have seen lot's of Saleen rears being shaken to pieces already, wich we haven't.

[PascaLM]

I don't think 2.6 Gs are possible for a Saleen which weight is 1100 kg. Two maybe, with good tyres and on a banked curve. An Audi R8 can "pull" 2,5 to 2,7 G max.

[Bramzel]

I think they are. Most GT's from the top-teams pull even 3G up Eau Rouge. This is not made up, comes from somebody who knows the figures. He also said that 2.6G as Max was on the low side, as it peaks out to near 3G. On average in the corners they do roughly 1.7 to 2G.

[edu]

About Z350:
"Em Suzuka, conseguimos passar pela curva 130R (logo antes da chicane) sem leventar o acelerador, a mais de 220 km por hora, com um G lateral de 2.9. Claro que de pneu novo, mas mesmo assim..."
http://www.gptotal.com.br/colunistas/divila_marco.htm

[MulsanneMike]

Originally Posted by lemanfan

Downforce is based on manifacture data that says that the car can run
up side down at 260 kph that mean 1250kg@260 kph!
Yeas it is hard to believe but I just want to find conditions at which can car produce 2,6 G of lateral load!

I must say I'm a bit skeptical of the downforce figures quoted above. That would be 2750 lbs. @ 161 mph which extrapoltes out to better than 4200 lbs. at the theorectical 200 mph. That is potentially more downforce or equal to many of the top LMPs. Based on the lap times between the two car types and noting their performance difference for reasonably known factors (weight, power, brakes, tires), I still have my doubts. Consider the Saleen's conservative aero architecture with its single element rear wing in close proximity to the production side profiled cockpit, the small rear diffiuser, and the lack of any kind of agressive front underbody solution and the additional lack of significant air management of that area (as it is limited by the car's production origins) leads me to further doubt the figures. GT type cars must maintain the production silhoutte from the wheel centerline upwards. So there are significant limitations to their ability to produce large amounts of downforce.

[Hauptmann6]

Originally Posted by MulsanneMike

I must say I'm a bit skeptical of the downforce figures quoted above. That would be 2750 lbs. @ 161 mph which extrapoltes out to better than 4200 lbs. at the theorectical 200 mph. That is potentially more downforce or equal to many of the top LMPs.

Remember the street version does have tunnels.

[Goran Malmberg]

2,6g in cornering force? I have been testing skidpad a number of times and not been close to that sort of numbers. Other cars like Koenigsegg has claimed 1,3g if I remember right. Then it showed that they called it "cornering power". I presume that this is not the same as a 360 degree skidpad circle test. There is a LOT of information to be delivered together with these number if they ar supposed to tell anything of value. On coold tires I was braking 1,06g at 60 mph on asphalt. On betong at the same air field the same day I had 1,09g! Over a 3sec avrage time basis. In cornering force I can easely take 0,1g away from a 3sec average as compared to a full 360 degree skidpad driving.
To run a 2,6g skidpad at say 240 kph, to get some downforce, we should need a 600 foot radious circle to make 2,54g!
If we get down to earth and use a 100 foot radious and have a 7sec lap time, we are also having 2,49g, but a speed of 100 kmh or say 60 mph!
Not very much groundforce then.

Goran Malmberg

[MulsanneMike]

Originally Posted by Hauptmann6

Remember the street version does have tunnels.

So the quoted aero figures are for the street car? Then they're not relevant to the GT1 racer at all.

[Bramzel]

Mike, the raceversions pull bigger figures than that. 3G up Eau Rouge is common for the big players in FIAGT.

[MulsanneMike]

Originally Posted by Bramzel

Mike, the raceversions pull bigger figures than that. 3G up Eau Rouge is common for the big players in FIAGT.

I'm referring to the aero figures. If the numbers quoted, 1250 kgs @ 260 km/h, are for the tunneled road car, then they have no relevance to the flat bottomed, diffusered race car. Hence my initial skeptisism about them to begin with. Very, very doubtful that a GT1 car could equal or exceed the absolute downforce performance of a LMP. Though I'm still very doubtful the figures are even relevant to the road car. Considering road car ride heights, there is no way it is generating those levels of downforce either.

Consider downforce:

Porsche Carrera GT:
493 lbs. @ 180 mph

Ferrari 360 Modena:
424 lbs. @ 180 mph

Extrapolated numbers for Saleen S7R resolved to 180 mph:
3438 lbs. @ 180 mph

So, based on that, It is clear that the figures aren't for the road car either.


Just for comparison:

2003 Lister LMP Storm:
3744 lbs. @ 180 mph

2000 Panoz Roadster S LMP:
3456 lbs. @ 180 mph

So, in conclusion, the above quoted 1250 kgs @ 260 km/h for the Saleen S7R seems to come from an over zealous PR person!

[Goran Malmberg]

My car is flat bottom and generate 50 mm of water at 75 mph. On a area of 36000cm2 this produce 396 pound of downforce. No difuser used, only 0,5 dgr of rake and 3 inches of front splitter height. At no rake there is almost zero water rise. More ride height and the downforce collaps accordingly.
At 150 mph there should be 1584 p of downforce, by calculation. But there is probaly losses out the side of the car, so we may take a fair ammount away
from theese numbers. We will see what different diffuser will add next summer. However, the rear wing add 150p at 94mph using a seriously sorted out possition. At original possition it gives zero downforce.
Goran Malmberg