Those clamps look really nice. I wonder if I could polish them? Seriously though the clamps on the rear roll bar legs are the clamps supplied by Stance (note Alex used the same clamps as I did) and they are more like flexible bands with some give. But tell me more about the canister expansion issue. I was not aware of this. And I REALLY like that quick disconnect coupler they used on the gas line!

I did not disconnect the reserviors so no immediate concerns with N2 pressures. I ran them as is from the factory.

Oh and the initial feedback I can provide is that they are very good LOL more later when I can look more at my notes.

Regards,
Crispy

 

Those silly dry-break connectors from Stäubli (IIRC $450 per corner) are quite expensive, but make things much easier to mount the canisters inside the Porsche. I only had them installed on the rears. If they came with those clamps then I guess they're OK. From my research most of these setups especially when exposed to extreme heat will expand. That's why I opted to mount my canisters outside the engine bay and inside the cabin. I know that's not possible for you fellas though.

Alex, I would be a little concerned w/ your canister on the IC inlet pipe though. Do you have any weird handling issues after a full session? I would think your N2 pressures get much higher on the right side than the left.
http://www.rennsportsystems.com/moton.html


You really should have measured your N2 pressure before the corner balance. Also, you'd probably want to put that info in your log book. I highly recommend this book for you guys buying these dampers: http://www.amazon.com/Vehicle-dynami...1281880&sr=8-1

I ended up buying this N2 gauge and bought a tank w/ a Harris regulator from Roberts Oxygen. The Moton, JRZ, and Ohlins need to be measured with the wheel off the ground, not sure about the Stance.
http://www.longacreracing.com/catalo...=1036&catid=19

Can wait to get some more feedback. I'm thinking about buying these for the FC!

 

Thanks for the link for the book. Looks good.

Yeah engine bay mounting for the front dampers is as good as we can get on the FD. I attempted to put mine in as cool a location as possible - near the headlight openings as far forward as possible recognizing the negative effect of engine bay head on the canisters.

I have not corner balenced my car yet...way too much on my plate before leaving for VIR...and note I do ALL my own work. I was pretty exhausted by the time I even got there! A quick garage floor alignment check was all I had time for.

I have a Roberts Oxygen shop near me...what size N2 cylinder did you buy? I have a pressure gauge/ N2 charging device from Stance.

Crispy

PS barring a few minor annoying issue the FD was a veritable rocketship at VIR this past weekend

 

Glad to hear everything worked out this weekend, but Chris you really need to get a proper alignment for your next outing! I highly recommend Geoff at ASG in Fairfax. He's very honest and will explain everything along the way. He's also been in the Motorsports business for many years and has been Leh Keen's and Patrick Long's crew chief and car setup guru.

OK, enough of that. I bought a small 20 CF standard size exchangeable tank regulator and short 300 psi hose. Does the Stance canister have a Shrader valve? I've discovered that you lose a substantial amount of pressure when you check the pressure with the standard Moton gauge provided. Not sure if that's the case with the Stance system.

Boyle's Law states that for a gas at constant temperature, Pressure * Volume = constant. So if you increase the volume enclosing the gas by hooking up a long hose, you decrease the pressure in the remote canister / hose system. The decrease in pressure is proportional to the increase in volume from the hose. So if you reduced the length of those hose by a factor of two, you would reduce the amount of pressure lost by a factor of two. Based on tests, that would reduce the pressure loss from 30-40 psi to 15-20 psi. Still too high. You want to get it down to the 1-5 psi range if possible, so you need to reduce the length of the hose by at least a factor of 10!

Note that the increase in volume from the hose connection is a combination of the pressurization of the gas inside the hose and any flexibility of the hose to expand radialy / lengthwise. So the best setup is a short metal connection, but a short hose would definitely improve things if it didn't expand much.

In short, shrader valve reservoirs are basically a flawed design.

I decided I didn't like the fill it and bleed it down method, finding it difficult to get the final pressure right. Think Heisenberg uncertainty principle - i.e, the act of measuring the pressures changes the pressures.
The Longacre link I sent you has a combination digital gauge and fill/bleed valve that works much better.

Oooh, another tool for the garage!

Most importantly, what were the lap times?!

 

Pat,
Does changing the pressure significantly affect ride height?

 

Peter,

It has nothing to due with ride height. By changing the pressure you are effectively changing the spring force. For every 10psi of pressure you are changing the spring rate ~6# of force on the 22mm shafts and ~2.5# on the 14mm shafts. Essentially it allows you to run a softer spring and then dial in what you would have obtained with a stiffer spring and no pressure. It's not meant to substitute spring rate as there is a defined range of pressure you can run on the cans but you can more easily hit your target from track to track depending on spring needs. Easier to dial in more spring rate with pressure than it is to remove spring rate as you will hit the floor more quickly.

 

Oh trust me I will. You should have seen my front tire temps!! A buddy of mine has a fancy Longacre tye pryometer/computer. So I ripped into the pits hot on my last session to check temps. Kinda what I expected but yes I do seriously need an alignment.
PM a phone number for Geoff if you wouldn't mind.

LOL too true!!!


I actually only looked briefly at the tapes. I'll let you know as soon as I pull some times. Please note this is the first time in 5 years I've driven Princess on the track and the first time in 18 months I've been on track at all so I was slow...not snails pace but no where near what I recall I was capable of in Princess years ago. So sad.

Regards,
Crispy

 

Does anyone have experience with the regular Stance GR+ coilovers?

I'm new to the FD scene, we all run Stance on our drift cars since they're local/friends of ours. I'm not planning on drifting the FD, so looking for any feedback on the GR+'s.

 

I can't tell for sure, but it sounds like you were trying to check & fill the reservoirs with a standard valve, which as you've pointed out always lets pressure bleed through the Schrader valve when you connect/disconnect. What you need instead for your tank & hose setup is a zero-loss valve* that lets you manually open/close the Schrader valve. That way you check and adjust the pressure of the damper reservoir + hose a the same time, then close the Schrader manually. Now that it's closed, you can disconnect from the Schrader and lose no pressure from the damper reservoir. You now get consistent pressures (with a decent pressure gauge).

You do need to be hooked up to the tank & hose to check, but with the small volumes involved, not much gas is wasted in doing the checks.

If the Longacre tool that you referenced is the same one that I have, then it includes a zero-loss valve. Penske also sold a pressure gauge/zero-loss valve that accomplished the same thing. I have both and they both work fine.

* I can't recall the proper name for the zero-loss valve, but I remember reading somewhere that it's used by HVAC techs. If that's true, then you can probably source what you need much more cheaply than the Longacre, Penske or similar tools. I'll bet that McMaster Carr carries something that would work...