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

As many, I do absolutely love what Kunos has delivered with the first Porsche Pack and can't wait to see the other upcoming packs later this year.

I do my Porsche consumption within Assetto Corsa piece by piece, bite by bite and car by car.
I spent the days since Porsche Pack 1, day 1 most of the time inside a Porsche RSR 3.0 cockpit, mostly around Nordschleife.

Curiosity brought me next to the Porsche 917/30 and I intent to understand and learn how to handle this one.

The car was pretty famous not just for it's outrageously insane power output for circuit racer in it's day (and continuous to be to this day), but it was probably most famous for the very few men who dared to tame this beast and be brave and skilled enough to race it in anger, Mark Donohue to be most noted.

When dealing for the very first time with the Porsche 917/30, most notably three things stay with you forever:

1) it's brutal acceleration once the turbos deliver their unfathomable power surge
2) it's unbelievably big Turbo lag, keeping the engine revs up over the course of a lap being a real challenge
3) it's spool differential rear axle which simply does not let any novice turn the car around a corner in the same fashion one would turn other cars

Here is a thread for everyone to chime in, share ideas, historic facts, stories and experience regarding to this car.

I'll start with pointing to an interesting discussion over at another forum I stumbled in today when searching for information about the type of differential Porsche engineers were choosing for cars as the mighty 917/30 (and later high powered Porsche endurance racers):

http://forums.autosport.com/topic/90682-mark-donohue-and-the-locked-differential/


… and yes, I have put Mark Donohue's book "The unfair advantage" is on my Christmas list too!

Big thanks to The Meco and Kunos to make this very car happen - only now do I slowly start to realize how important this very car is - in history - in simulator racing and in learning about technology and one's skills how to tame it.

 

Cool

I know little of this car's history, always nice to connect more with the simulated version of a track or car.

Thx!

 

As I said in an other thread, after driving the 917/30 every other car seems like my son's Bobby Car.
Some curiosities:
- the car was also known in North America as "Turbopanzer"
- during qualify with max boost the car reached 1.580 hp and 1.112 Nm torque: the most powerful race car ever
- the torque was so high that in some cases a slip between the rim and the tyre was experienced
- when asked to Mark Donahue if the car was too powerful, he answered:"It will be too powerful when the rear tyres slide when accelerating in forth gear in the straight"

 

It was the first car I tried and maybe I made a mistake because the rest of the cars seemed like golf carts after trying the beast but I was surprised to find out that it is actually driveable even at 100% boost and even at the Nordschleife. Short shifting and feathering the gas in 1st and 2nd gear, lifting the gas to lower the front of the car to aim it correctly before a corner, that was all I needed to.. survive. Of course being fast is another thing..

 

Yup. I was surprised how easy it was for me to handle.

I have had a hell of a lot tougher time getting to grips with the 935 and RSR. Default setups of those are very unsuitable for me--especially the RSR.

I haven't spent too much time in the 917, so I don't have a whole lot of comments. Yet.

 

Wasn't so much an issue for me so far in the 917.
In the 935 on the other hand I ran into this when we raced at the Nordschleife Endurance (well, wanted to, got pushed out on lap 1).
To achieve a proper top speed and to adapt the gears to the corners at the ring, I had to raise first gear so I could use it in more corners.
However, in the first/second corner after start/finish (tight right, tight left) the revs dropped so much that there was a lot of turbo lag.
The solution I chose was to clutch out midcorner in T2, rev up and clutch in again.
That means that the rear wheels will spin and you have to powerslide out of the corner, which however is quite controllable due to the rear locked axle.

Didn't try this so far with the 917, but with some practise, I think you can get it working.
Maybe use the adjustable turbo to lower the power for some corners and raise it after you're "safe".

I really need to get into that 917 again, didn't drive it since release day (ok, did a small test on the drag strip, but that's about it ).

Again, I didn't see this much of a problem in the 917, but rather the lack of overall grip at the front.
The only thing you shouldn't forget is to downshift into the lowest acceptable gear. If the gear is too high, then it will understeer.

Edit: Should also mention that imo both the 935 and the 917 suffer for a fifth gear.
Can understand though why Porsche built this setup into these power-beasts.

 

So in simple terms having no diff makes the ridiculous wheel spin in low gears easier to handle???

 

To some degree, yes. But the more power you have (=the more wheel spin), the harder it will get. Also might depend on the ARB.

IMO, power-drifting out of a corner in the 935 is really easy, if you have a decent throttle control on your right foot.
At said T2 on the Ring, I only spun it once on one of the first tries, after that it really wasn't a big deal to hold it (maybe around 20 laps or lap starts in total).
Didn't need to do so in other corners, but if the back let go, it was still easy to catch.

The 917 I only drove for those first 4 laps around Tourist on release day and didn't touch since.
Back then, I was of course quite cautious (especially since a lot of other cars were on the track), so I didn't really try to powerslide it.
But at least if the back stepped out occasionally, I was able to catch it without breaking out in a sweat.
Guess it could work pretty much the same. But then, the turbo lag on it isn't as bad as on the Moby Dick, so maybe it's not a big deal anyway.

 

My recipe for the 917/30 is this:

1.) Braking only in a straight line
2.) Coasting until apex
3.) feeding the power gently from there
4.) Shortshifting from 2nd to 3rd
5.) finding some talent

I've got points 1 to 4 covered

 

Shortshifting why? You have only 4 gears, use them all.

 

Yes but you can only use 1/2 throttle in 1st and 2nd...

 

You need to be on the throttle before the apex. Spool diff life.

 

Still can't drive it, like, at all.

It's fun, tho With my level of (sim)racing experience, cars with effectively no diff feel counter-intuitive to what I am used to. Slow corners kill me. Threw it around my favourite shakedown location tourist nords for an hour or two some days ago, but I feel as if I'm losing half a second out of every turn because I am WAYYY WAYYY too late on the throttle. Also, wtf powah.

 

I saw Dennis streaming himself driving it on Nords Tourist trying to get WR... I tried too and yeah, RIP these guys

 

Yeah yeah, just when I thought "Alright, this Dennis Lind guy beat me by less than a second, so there can't be THAT much time left on the road"...

A wild William "excuse me, you dropped 10 seconds back there, here ya go" Levesque appears!

 

Just remembered that I saved that lap, here:
https://www.dropbox.com/s/h40e0gp05...dschleife_touristenfahrten_051116-171019?dl=0

 

Insight into where those elusive seconds are hiding, excellent. Not that I'll catch 'em, but thanks nonetheless

 

- don't short shift (modulate throttle instead)
- keep the rev counter up and the Turbos spooling during cornering
- the car with it's spool diff will turn under acceleration and will plow straight ahead when coasting
- during fast switching corners left-right-left … you need to dance the car through the turns, keeping it unstable and on it's tows (don't steer with the steering wheel only and keep it always dancing)

 

check. It's probably the achievement I'm most proud of yet.

ch.. DAMN this is difficult. It just slips away on me sometimes. My mind keeps interfering, saying "Slip angle is your enemy. You slide, you lose. Slick tyres hate you for it."

almost check. Got my head wrapped around the principle, but I feel as if I have to defy my muscle and visual memory for the required difference in how you approach the corner

Yeah, this is a combination of things you have to keep in check. It's soooo difficult to balance it all.

But it's soooo rewarding when you get it right. I'm probably one of the slower guys in simracing, but for the sake of improving on oneself and reaping the rewards of continuous practice, I predict lots and lots of hours of frustration, anger, relief, and happiness with that notion. It's not keeping it on the road that is so difficult (the car is surprisingly stable when you look at its RIDICULOUS stats), but negotiating the limits is, as it's such a different animal. Out of the cars that go pretty fast around the ring, I'm used to the C9 the most (which almost has only half the horsepower of the 917, but goes faster on a straight line because LeMans downforce, yo), and it felt like a modern open-wheeler after practicing with the 917. Almost makes you feel like the C9 has too much front grip in general.

I highly doubt I'll ever get below 6:10 in the 917, but I'm at a point where I can say "damn, half a second quicker, that's a lot! let's find the other half.", and that's pretty important for my motivation. Last year, I felt as if doing laps that differed north of 5 seconds from each other on such a long track were kinda consistent. Kinda outrageous in hindsight. I wonder if there's improvement to be made once I switch out my swivelling office chair for a proper race seat. Gear acquisition syndrome is a b***h tho, especially when you're already a musician

TL;DR: Improving, albeit slowly. Motivation is high, fun outweighs frustration. Hopeful it stays that way.

 

I always treat the 917/30 as a bit a special candy.
I wouldn't have the nerve of running it all the time but do a few laps on occasion which makes it all feel very exciting and special.

Although I posted those few check points I try to keep in my head around a lap above by no means do I fully adhere to them.
There are always those laps around the ring when you run a few slow clean laps to get used to the car and then on lap 4 or 5 you start to attack and half through the track plow the car straight ahead, understeering into a barrier at slow motion speed ;-)

@ Fairbanks, consider yourself the fasted man around Nordschleife on an office chair with 1200+ HP ;-) It kind of sounds cool to me.