AC DRM Revival @ Riverside Int. Raceway Long - Fri 13Apr18

[Jakal31]

3 hours and "endurance race" do not belong in the same sentence!

Pssst. If endurance racing is to be had in these things we've got to do at least a 6 hour run.
Since AC gives us no driver swap option, that 6 hours should be enough to cause some of the suffering associated with endurance racing. (Man, that would be awesome, by the way!)

3 hours?
3 hours is just getting started!

 

[Tbear]

I was never involved in touring and GT car racing in the 70's and 80's but from my understanding I would think that not just spring preloads with fixed spring rates and exclusively a single fixed valve air damper were available to the teams back then.

I would think at the least several spring rate options and of course differently valved air shock absorbers to match different spring rates and especially entirely different track characteristics were used (you don't run the same spring damper combinations on the Nordschleife and on the Norisring).

Maybe this could be an option for a future "suspension package update" to the mod once you guys have the time and energy to bite into this topic ?

I am not completely certain about the 935, but having worked on Porsche motor cars back in that time period, I seem to recall that both Koni and Bilstein racing damper inserts were adjustable, but not the oem Boges.

This was not an adjustment that the driver would make from inside the car. A mechanic would have to remove the strut assembly from the car, disassemble it and remove the damper. The adjustment was made by compressing the damper to engage the internal adjustment mechanism and turning it's shaft clockwise. There were three adjustment positions.

It's hard for me to believe these cars didn't have adjustable dampers especially considering the condition of the surfaces of the race tracks at the time. An email to Koni or Bilstein could get the historically correct information for all Group 5 cars.

EDIT ... I've sent an email off to Koni in attempt to get the correct historical data.

 

[DRM Modding Team]

Here is orignal manual from the Porsche 935 K1, no information about adjustable dampers.

https://drive.google.com/file/d/1f2tpw6TATPv4qhyjfgS3LZcI9EOdPe5h/view?usp=sharing

Same Information for the 320er, Escort and the Lancia from a german racing driver. Maybe he can't remember, but thats our information about the cars.

But it would be interesting to know what caused the damper to turn

 

[Tbear]

Here is orignal manual from the Porsche 935 K1, no information about adjustable dampers.

https://drive.google.com/file/d/1f2tpw6TATPv4qhyjfgS3LZcI9EOdPe5h/view?usp=sharing

Same Information for the 320er, Escort and the Lancia from a german racing driver. Maybe he can't remember, but thats our information about the cars.

But it would be interesting to know what caused the damper to turn

The Porsche Factory Manual shared above is not a workshop manual and does not show the modifications made by Kremer and other 935 tuners.

The "K" in 935 K1 (and K2 and K3) stands for Kremer. They received 935's from the Porsche Factory and modified them into their own cars. Check HERE.

Quote from that article: In 1977 Porsche started selling the 935/77A to customer teams, creating a lucrative business. In the meantime they kept themselves busy by constantly improving upon the concept. Countless iterations of the car followed, but none were sold to Porsche's many customer outfits. Tired of waiting on the hesitant manufacturer, German private entry Kremer Racing began work on an evolution of their own. Kremer Racing was run by brothers Erwin (driver) and Manfred (engineer) Kremer. The pair had introduced a 935 K1 variant in conjunction with Porsche back in 1976. As established Porsche dealers turned race car designers, they felt that the already dominating car could still be improved upon.

I think I would check with Bilstein or Koni for the correct data on dampers used in Group 5 cars.

For fans of the Porsche 935's this page has a lot of great information and illustrations for skinners.

 

[Stig Bidstrup]

Adjustable dampers ? or not ? on Kremer cars in late 70s ???
Why not go to the horse´s mouth : https://www.kremer-racing.eu/kontakt/

 

[Dirk Steffen]

@ Kevin: Which post processing effect you use?
Have you set/test it as we recommended at the manual = "default"?

@dirk:
It is possible to change the spring rate and the ride height. You mean it is not enough? The values about the suspension in Hz with emtpy and fuel tank on different tracks are ok, so we have deactived the advanced the suspension.

enduraces tire: Yes, it would be a great idea, we will discussing it internally.

It's all good in the setup.

I often just wish for more setup values to tinker with - I love tinkering ;-)

Optional endurance tires would be great to have at some point.

3 hours and "endurance race" do not belong in the same sentence!

Pssst. If endurance racing is to be had in these things we've got to do at least a 6 hour run.
Since AC gives us no driver swap option, that 6 hours should be enough to cause some of the suffering associated with endurance racing. (Man, that would be awesome, by the way!)

3 hours?
3 hours is just getting started!

Hey man, some of us are on their second heart transplant, some have only half a lung, some can't get a good night's sleep without three visits to the bath room, others are just old farts which is why the young kids are always winning the club racing events while we are watching and reminiscing in our young years long past.

For us, ANYTHING that takes longer than a hump on Sunday is considered ENDURANCE

 

[Tbear]

Adjustable dampers ? or not ? on Kremer cars in late 70s ???
Why not go to the horse´s mouth : https://www.kremer-racing.eu/kontakt/

I think it might be better to check with the shock absorber manufacturers who built the dampers for the cars raced in the series. Here's why: Porsche was not the only car and Kremer was not the only Porsche tuner in the series. Although both may have been involved with developing dampers, neither Porsche OR Kremer built them. Further, just because, for example, Kremer didn't use adjustable dampers, this does not mean that other cars didn't as well.

The photo above is of an actual up-right from the front of a Porsche 935, For the record, at the front of the Porsches they were fitted with a McPherson strut type upright that a damper INSERT was installed into, much the same way you could replace the innards of a common retractable ball-point ink pen. At the rear of the car a more traditional coil over shock was fitted. At this time period BOTH types of dampers could be had that were adjustable.

On the other hand, BMW DID build it's own cars. Here is a nice article a with pictures of the 320 s Turbo. BMW used a damper arrangement similar to that which was in the Porsche 935.

I just received a very nice email from the Automotive Product Manager for Koni. He explains that almost all of the people involved in racing back then have retired long ago. However, Koni has kept the records and is very willing to do the research to determine specifically what type of damper was used in the Group 5 cars.

As for the Kremer Porsche 935 K-1 through K-3, off the top of his head, this manager thinks it a good idea to reach out to Bilstein, because of the close relationships between them and Porsche over the years.

I am still waiting for a response to the email I sent out to Bilstein.

Much, I'm sure, to everyone's chagrin, I'm going to keep digging.

 

[DRM Modding Team]

I have send a mail to Bilstein too......., and talk with Koni. Tomorrow i habe meeting with Kremer about the damper and the suspension. At the telephone the Koni-Guy told me,he can remember that Koni have since 1975 damper with adjustable bump and rebound.

 

[Tbear]

I have send a mail to Bilstein too......., and talk with Koni. Tomorrow i habe meeting with Kremer about the damper and the suspension. At the telephone the Koni-Guy told me,he can remember that Koni have since 1975 damper with adjustable bump and rebound.

http://www.koni.com/About-KONI/KONI-s-racing-history/

... The KONI shock absorbers offered better damping characteristics and the possibility to mount the spring around the damper (i.e., coil overs. Ted note.), which made it more compact. The first official (F-1) Grand Prix that KONI participated in was in 1958 with Ferrari.

 

[Stig Bidstrup]

I also looked a bit but gave quickly up, since you cant be sure what you're looking at are some after market damper made in the 90s ore later --and that really don't counts..
The cars are still racing in Classic series around the world in top trim . So parts are of course still being made but in other and more modern configurations -- Brake parts for example..

 

[Tbear]

I have send a mail to Bilstein too......., and talk with Koni. Tomorrow i habe meeting with Kremer about the damper and the suspension. At the telephone the Koni-Guy told me,he can remember that Koni have since 1975 damper with adjustable bump and rebound.

Even if the dampers were not adjustable on the cars, they were not off-the-shelf units that couldn't be tailored to suit the needs of the driver or the track. Ask your Bilstein-guy about custom valving and rebuilding/re-valving that can be done by both the Bilstein factory OR the mechanic working on the cars. Bilstein still does the same thing today.

 

[DRM Modding Team]

Today I have a nice conversasion with Kremer, Mr. Feist and Mr. Heuser.
Mr. Heuser was the mechanic who prepared the vehicles from K1 to K3 for Wollek , Ludwig at the racetrack. He said, he can not remember that they were able to adjust the bump and rebound of suspension strut on the K1 to the K3. The function came at the beginning of 80th and was used from Kremer on the K4.

After the guys of Kremer opened our Website http://drm-modding-team.com, they were thrilled and invited us for coffee, cake and a visit to the company. GREAT !

But, when all need some adjustments for advanced damper section, no problem, some weeks before the release we deactivated the adjustments into setup. So, we have spend much more time as we want for the bump and rebound theme. Now, we have switch to develop a endurance tire

 

[Bobby Pennington]

Today I have a nice conversasion with Kremer, Mr. Feist and Mr. Heuser.
Mr. Heuser was the mechanic who prepared the vehicles from K1 to K3 for Wollek , Ludwig at the racetrack. He said, he can not remember that they were able to adjust the bump and rebound of suspension strut on the K1 to the K3. The function came at the beginning of 80th and was used from Kremer on the K4.

After the guys of Kremer opened our Website http://drm-modding-team.com, they were thrilled and invited us for coffee, cake and a visit to the company. GREAT !

But, when all need some adjustments for advanced damper section, no problem, some weeks before the release we deactivated the adjustments into setup. So, we have spend much more time as we want for the bump and rebound theme. Now, we have switch to develop a endurance tire

I sure hope you get to visit them. Great news

 

[DRM Modding Team]

Kremer is only 500 km away.........