Renault R31

[shelly]

"We also know that the forward exhaust, by contrast, performs more strongly once the rear ride height starts to compress"

I think this is the most interesting sentence in the interview.

[Pieoter]

I think the FEE was a serious mistake not because it didn't work but because it goes against how, atleast how I have been taught, to setup a racing car. If you optimise your car for the high speed corners you will lose in the slower speed corners and vice versa. This is why you should, in general, have a bias towards slower speed corners.

The problem is that since high speed corners take much less time to complete you gain much less than than you can in slow speed stuff.

[beelsebob]

I think the FEE was a serious mistake not because it didn't work but because it goes against how, atleast how I have been taught, to setup a racing car. If you optimise your car for the high speed corners you will lose in the slower speed corners and vice versa. This is why you should, in general, have a bias towards slower speed corners.

Huh? Your statement didn't indicate any bias being beneficial at all. Optimising for slow speed gimps high speed, optimising for high speed gimps low speed.

[Fil]

Beelse, this bit..

The problem is that since high speed corners take much less time to complete you gain much less than than you can in slow speed stuff.

[beelsebob]

Beelse, this bit..

The problem is that since high speed corners take much less time to complete you gain much less than than you can in slow speed stuff.

Except that it's simply false. Since when do the high speed parts of Silverstone, Sazuka or Barcelona take less time to complete than the low speed parts?

The RB6 proved that optimising for high speed cornering can indeed give you a good car. That's why so many teams (McLaren, Renault, ...) optimised their car too much for high speed this year.

[raymondu999]

Pieotr, how aero-heavy a car are you setting up? How fast are the circuits you're working with? How fast are the fast corners and how slow are the slow corners?

[Fil]

Beelse, this bit..

The problem is that since high speed corners take much less time to complete you gain much less than than you can in slow speed stuff.

Except that it's simply false. Since when do the high speed parts of Silverstone, Sazuka or Barcelona take less time to complete than the low speed parts?

The RB6 proved that optimising for high speed cornering can indeed give you a good car. That's why so many teams (McLaren, Renault, ...) optimised their car too much for high speed this year.

I don't think there's an absolute answer that can be given to be honest, as it varies too much from team to team, and track to track.
But it is clear that Renault have isolated their lack of low speed pace as the major reason for their drop in relative performance.

In the R31's specific situation, they are not gaining enough in their high speed pace to counter their lack of low speed pace.

[mith]

I still wonder, if there isn't another reason to their lack of speed in slow corners. They had very good mechanical grip for years, but switched to pull-rod this year and thus their rear suspension might not be optimised yet.

[PlatinumZealot]

I think the FEE was a serious mistake not because it didn't work but because it goes against how, atleast how I have been taught, to setup a racing car. If you optimise your car for the high speed corners you will lose in the slower speed corners and vice versa. This is why you should, in general, have a bias towards slower speed corners.

The problem is that since high speed corners take much less time to complete you gain much less than than you can in slow speed stuff.

Easy to say now but during development the Renault windtunnels were showing the FEE to be superior in both high and decent low speed. In the real world the compromise showed much greater. Remember, this was unknown territory.

[Pieoter]

Beelse, this bit..

The problem is that since high speed corners take much less time to complete you gain much less than than you can in slow speed stuff.

Except that it's simply false. Since when do the high speed parts of Silverstone, Sazuka or Barcelona take less time to complete than the low speed parts?

The RB6 proved that optimising for high speed cornering can indeed give you a good car. That's why so many teams (McLaren, Renault, ...) optimised their car too much for high speed this year.

Use common sense ofcourse a high speed corner that is 3x longer will take longer to complete, but please dont nitpic. Lets have a look at redbull this year because everyone loves redbull. At monza they optimised the car to power out of corners and not for top speed and won at a track.were many said they would do poorly.

Yes it is very easy to spot mistakes looking back not so easy looking forward.

[Intego]

I think Pieoter's argument was the gain in a corner: Imagine a track wit the same amount of fast and slow corners. You can gain let's say 0.8 seconds a lap when setting your car up for slow corners and 0.5 s with fast lap setup. Which do you choose?

My next thought was: Did LRGP ever tested without FEE and without EBD? Do we know whether FEE is faster (or not) than nothing?
I think with FEE they managed to feed the diffusor with some exhaust gases. But the rivals approach is another: The exhaust gases seal the diffusor and Red Bulls slotted gurneys effectively enlarge it (ScarbsF1.com). So we can say the Renault diffusor just is to small.

[ringo]

time is not the factor.

The main issue is what the FEE us doing at certain windspeed, and certain attitude of the car.

Hate to recycle stuff from the FEE thread but in this video:
[youtube]http://www.youtube.com/watch?v=8CtLB7g5s9s[/youtube]

Notice how wide the gas blows at slow speed. This happens everytime the car is in a slow corner. The exhuast is not tuned to work at those speeds.
In this case tuning refers to the pipe angle to the center line of the car.

Now when rake is increased, this layout doesn't have a constant energy flow to the diffuser. The downforce is made in the center of the car and the diffuser benefits indirectly from the lower pressure gradient from the front of the car going towards the back.
For the rear blown cars, the blowing is constantly in the same place regardless of what angle the rear is at, as it is fixed to the rear of the car. Therefore it is at peak performance regardless of attitude and car speed.

The R31 gets even more complicated with yaw transient.

The concept is good, but too many variables to consider.

[Lycoming]

optimising low speed is preferable to an extent because you can get on the power sooner, and the exit is far more important than apex speed. If they knew theyd be weak on slow corners from day one, Id be curious as to how the decision came about.

also curious as to why they were so strong in australia.

[Donuts]

Tip! There's a really interesting article on Mikolaj Sokol's blog(http://sokolimokiem.tv/). The subject is how Lotus Renault GP is going in the opposite direction from Mercedes GP. Basically he's pointing out that we should not expect to much of Lotus Renault GP in the coming seasons. Firstly beacuse they lack a whole season of running a "normal" exhaust and secondly beacuse James Allison is the only one left from the championship winning era. There are some interesting examples from the past...

[dren]

A car that is fast in mid to high speed corners should naturally be fast in slower speed corners unless the downforce is being created in a dependant way like Ringo points out. You most definitely want faster cornering speeds. High downforce will allow for higher cornering speeds, less braking/shorter braking and enable you to get on the throttle quicker out of the corner. A good mechanical set-up certainly doesn't hurt.

What is surprising is the Renault this year lost the low speed prowress it had in previous years. Perhaps the car could generate a lot of downforce, just not as efficiently as others?