Porsche 917/30 - some ideas how to deal with the beast

The aero is really funny in this car, you can tell it is rather primitive. At RIR you can end up running pretty wide at T1 if you get it wrong and the front lifts over a certain crest every lap. Trying to make corrections at high speed can have hilarious consequences... Really fun car!

A fun and quite difficult challenge (unless your a little green fella) is to try and beat Mark Donohue around RIR short course. He did a 1:10.2 in 1973. I gave up at 1:10.3 but had a lot of fun trying to get closer.

Here's my best attempt, please excuse the editing... I was bored! A steam friend of mine mentioned there were highs of around 30c that day in that area, I used 26c and 100% grip.

 

You do good work when you're bored nice video.

 

Damn, nice time! I will give that a go.

Nice editing. Good music choice; I love The Doors.

 

Thanks I had to google "music from the 70's" but I think it fits as well, the fade out isn't great though!

I highly recommend giving the Donohue challenge a try, it is one of those cars were you can gain a lot from small improvements. I'd recommend 9 or 10 for the rear wing (with gurney flap 1) or the car is very nervous at speed. Stick at it and the lap times tumble.

 

Very cool that you got that close to his time. Makes me feel even better about how close the track is to what once was.

Side note: I vaguely remember reading in the Riverside book I got that Mark was claiming he would reach speeds of 240MPH when they got to Riverside and the full back straight. They switched it to the short course for that very reason.

 

I don't blame them, at the short course in AC it still reaches speeds in excess of 215 mph!

 

Great video, and one hell of an impressive lap! I've tried and tried to get close to that time and the best I've done is a 1:14 something I'm way too slow in the final two corners leading on to the back stretch; just can't get the damn thing to turn. I know you're a better driver than me but is that the default setup?

 

Thanks
I don't understand setup so don't blame me if it is rubbish but find attached the setup i was using... I just click stuff and then try it.
I put in quite a few laps and the time kept on dropping. Certainly wouldnt be easy to beat Donohue though. Keep at it and i'm sure you can get closer to that 1:10.2!

 

Good god man

Were you on uppers when you made a 1:10.3?



I spent about an hour tweaking the setup and running laps. I think I did something like 35 laps. Of those only a handful were valid...

Then I tried your setup, which took .915 off my personal best.

Time: 1:13.652

What you achieved with your setup:

Really high down force throughout, compared to default. You lowered the front ride height a lot, and it gained a ton of front down force--through the Venturi effect (link)--which reduced a lot of understeer at medium-high speed. I was really surprised there was so much down force to be gained on the front. Good job.

Obviously you took the rear to max as well.

And then you got the gearing pretty much spot on. What was up with the higher tire pressures?


Overall, I felt your setup allowed way more speed through T1, T2, The Esses, and T9.

It didn't do much for the slower corners.


One thing I struggled with at the beginning is T6 exit. Right after you come out of that bit**, there is a little dip in the track I was losing traction at almost constantly--thanks so much for your accuracy @LilSki!

Well you exit that corner on throttle obviously, so R Dampers are in Bump, but you hit the dip and they go to Rebound, and the default setting is too restrictive; the damper doesn't extend fast enough to keep the load on the tire the same as it was while you were in Bump--and there goes a spin out.

Other notes: I like the 917 and 935 a hell of a lot better with softer dampers and ARBs.


Finally

I just re-watched your video. Obviously, overall you are doing better than me. 2 things you are doing which I didn't try:

Very early short shift exiting T8, and T9. I bet I am losing a lot of time by not doing that

Cheers "Little Green Fella."

 

Great challenge...i hope to got time to try by myself in the next days, Mark Donohue was a myth.
That same year im born...

 

heheh thanks man, really interesting to read your thoughts on my setup I always have an idea of what im trying to achieve but you cant just isolate 1 thing and change it and I dont check dev apps so its always in the back of my mind that I may have made the car worse.
I'd set psi to give me correct-ish pressure for a couple of hotlaps at 26c mid clear. IIRC when I first pull away (using blankets) the pressure is too high but the tyres cool a little and its about right, or so I thought. I dont think I touched dampers, too complicated for me

nice lap time! glad my setup helped a bit, I dont know how many laps I did but im sure it was more than 35.

regarding T8/T9 exit, I got less wheelspin that lap than I was most others. I think id done better in 1st gear on other laps though, giving it a bit more throttle to get the old girl rotating... but its risky and I was up on my delta so I played it safe changed to 2nd and tried to get some power down. on some other attempts I span up in 2nd and had to change to 3rd much earlier.
i'd recommend trying a short shift or 2 there if you havent so far. next step is a 1:12, maybe good drive out of T8/9 will get you there!

 

I softened the rear springs, softened the front anti roll bar, it seemed to help a little. Lower rear tyre pressures by 4 psi.

 

Damn, nice driving mate. Also epic tune.

Think I know where you went wrong - you stopped the song just as it was getting going....

Personally I always gain at least two tenths when I listen to LA Woman

 

Mojo risin', gotta mojo risin'
Mister mojo risin', gotta keep on risin'
Risin', risin'

 

Good point, I can see where I went wrong now. Couldn't have told you why but I felt the fade out wasnt right... now I know why, it happened before the end of the song

 

There's a killer on road, His head is squirmin like a toad.

 

Take a long holiday

Let your children play


If you give this man a ride

Sweet family will die

Killer on the road

 

Not really anything to do with driving it:

 

I've try a short session of 30 min. yesterday, and my best time was 1:13:840 it's a long road till 1:10, LOL!

Why don't create a server with that challenge?

 

Jim's attempt (Mustang Shelby '67 if I'm not mistaken)


Cheers
Robin