belz

Interested in comments / opinions from anyone who has ProTrac dampers on their car.
I am contemplating double or triple adjustable dampers for my race car and I'm soliciting information before I pony up the $3-5k.
Considering:
1) JRZ ($$$)
2) MOTON ($$$)
3) ProTrac ($$$)
4) LEDA ($$)
5) Ohlins ($$$$)
5) other? suggestions?

Skip

Hi Mike!





No remote reservoirs or hyd lines to deal with, 8 steps of adjustment for bump and rebound all from the bottom of the shock (w/o removal), no heat-sensitive pintles, custom valved by Koni-na to *your* specs. Bolt-on complete kit with choice of spring weights.

Hey, you said "suggestions?"...

Tabor

I thought you weren't done with the front kit yet?

belz

Skip ... I forgot that you had mentioned these @ Rose Cup. When will they be available and approx. how much $$?

Skip

Fronts are done, but pricing isn't solid. Let me go rattle a cage.

Waiting for the first guinea pig... (though they are currently installed on Jason's 951S)

Skip

belz

Hey Skip ... what are "pintles" and what happens when they get hot? Sounds bad ... whatever it is.

Skip

Pintle is maybe a bad term since we use it more here to describe fuel injectors. I guess maybe "needle valve" is more appropriate.

Anywho, some (not all) adustable dampers use a needle-valve to control the bump and/or rebound adjustments (from the damper body or the remote can). The problem (however slight it may be) is that heat can change the flow characteristics via swelling of the valve components or changes in the viscosity of the oil. I don't want to play this as the tell-all advantage of one over another, it's simply one of the differences in damper technology, and one that Koni does quite differently than others. Konis use more of a ported disc with a limiting disc to change the flow of fluid. This means very consistent and long-lasting dampening. That's probably a horrible explanation, good thing I'm not an ME Another difference from others is that this is a Monotube High-Pressure Gas damper, and controls all the damping force at the piston which makes it very precise and quick (no lag).

Just to brag them up a bit more, various renditions of the 28 series dampers are in use by cars in F1, IRL, ELMS/ALMS, FIA Euro touring, Porsche Cup, etc...

Skip [shameless]

belz

Thanks for the clarification ... needle valve I understand ... "Pintle" threw me.
I'm very interested ... I think you said Jason has a set on his car? Do you think he'd be willing to post his comments here or should I give him a call?
Personally, I believe the needle valve / heat issue.
The remote can issue is one I haven't settled in my mind yet. The one plus I see with JRZ / MOTON / ProTrac is the ability to change the nitrogen (gas) pressure which effectively allows you to fine tune the "spring rate" as well.
Every 944 based vehicle I've seen with remote cans mount them in the engine bay ... doesn't the heat effect them? Why not route them inside the cabin? Any comments?
As you can see I haven't made my mind up yet.
If the Koni 28 series does everything they claim ... they may be the best all around comprimise (I like these kinda comprimises!)

belz

I can't spell ... idiot
"compromise"
(had to spell check in word!)

Skip

You should call, it's a great story

Yes, but weren't you the one who said that adjustable shocks are a gimmick LOL Just yanking ya chain.

Koni obviously takes a different approach to this. They believe that you valve the damper to the specifications of the car and its' uses, then use the 8 points of independant bump and rebound adjustment to fine-tune the characteristics and capabilities during track sessions, and in changing environments.

My only skepticism of the gas charging to change rate is; how do you know what you've done? You don't dyno the shock once it's done, do you? Is it possible that the damper would no longer be balanced? This isn't rhetorical, I really don't know the answer

A compromise at best... mount them anywhere but under the hood and you can't reach the adjustments, or they're in harms way... mount them under the hood and expose them to heat (especially on 911 rears and your Turbo... header on one side, turbo on the other). Running them into the cabin may be a) against the rules, or b) exceed the recommended hose length. If mounting in the engine bay, especially on the Turbo, I would at least form a protective cowl around them to reduce exposure.

No problem, it's great to get all this out in the open... I wish others would join in here and correct us where we go wrong.

BTW, I suk et speelin two

Skip

belz

"gimmick" did I say that?
The whole deal with the JRZ/MOTON and adding the gas to effect spring rate scares the cr-p out of me. From what I've been told there is a "relationship" between the amount (lb.) of gas and the compression / rebound adjustment. If you change the gas pressure you need to fine tune the compression and rebound. This gets even more complicated if you go with triple adjustable shocks! Yikes.
I can see my self sitting in the pits staring into space not knowing what to do next.
I'm trying to understand all of this so I can make a "good" decision with no regrets.
Maybe I'll just leave my Bilstein Cup stuff on and drive like hell!!
This constant improvement stuff is giving me a headache.

Skip

Honestly, I know the feeling. Sometimes the reference to racecar adjustability saying "that's just xx more things you can screw up" is right on the money. Seems we all have to attend engineering school for a year or two before we use race gas or place corner weights

Might be easier to walk. Good luck with the "no regrets" approach. I regretfully imagine you'll have as much luck as I am finding the "best computer".

Good Luck!

Skip

Nicolas

Hello

I have a 968cs with JRZ triple at the rear and in the front.
The setup is very nice and very easy to tune quickly ( low velocity and middle velocity ****) the pressure is not really a headache.
the main advantage of the remote reservoirs is to keep a low temperature of oil as well as have quick access to adjustement ****.
The JRZ are bolt-on for front and really difficult to mount for rear:
- need to fabricate a bracket / washer for chassis mounting ( grinding a part of the upper chassis bracket)
- you need to switch to coil over w/o torsions bar ( or to difficult to tune the ride height)
- personnaly I have changed the stock hose for a longer one to install the oil can in the rear side compartment (protection from dirt and heat of exhaust and great accessabilitty
- Front 350 Lbs springs / Rear 425 Lbs
I think the LEDA are something more Street european tuning than really race shocks
The koni's looks great and are more a compromise between street and track with a good range of adjustement but are really race stuff...
Look also for BILSTEIN RACING they are really working great on 944.

Good luck

Nicolas

Nicolas

... I wanted to write that KONI's are not really race shocks....

PS: If you want a nice car for track and still use it on the street , invest maybe is something like PARAGON'S Koni and convert your suspension to plastic or ALU bushing because all these rubber is really going to suffer from heavier springs and shocks.
About the kokeln torsion tube it is looking really nice but maybe to expensive for just some welded ( go on lindsay racing site and look for their 944 project)
The kokeln shifter is also a very nice part.

ATTN SKIP:
I have ordered from PARAGON a headset gasket package for my 968 CS and the P/N looks like it is for 944S2 , is there a big difference or is it just missing the variocam gasket or else..

Skip

Nicolas: Just to clarify, we are talking about the Koni 2812 and 2817 applications for the 944/951/968. These are strictly race dampers.

Jason will handle your head gasket question.

Skip