U2SLO and I will be testing a new component to change the compression and rebound forces of the Apexi N1 strut. This will enable the user to change compression and rebound forces with nitrogen pressure to change what the driver feels without removing the spring or the strut. The concept is for the daily driver who also competes in drag, autocross, and track days. On the drag strip you can have less compression force and more rebound force to control to help weight transfer or in autocross or track day event, increase the compression force to stiffen the what the driver interpets as spring rate. In the past these struts have only had one adjustment, with this it can be tuned for any track condition. Please contact Jarrod at Buschur's if there is enough response I will take the next step to production. Thanks, Indy Edited for clarity

 

How does changing the compression damping affect your ability to remove the spring? And how does the spring rate change if you don't actually change the spring? Where are you planning on reducing spring rates to control weight transfer?

 

Changing nitrogen psi alters the spring rate up or down. Light psi springs react quicker than heavier springs. Add rebound or remove rebound to control the compression.

 

+1

Compression valving does not = spring rate. Yes you can jack up the valving a ton and simulate this, but that's not the same thing. And it's not really even ideal for most set-ups other then A Stock auto-x competition where you can't touch the actual spring.

Maybe an idea worth looking into, but far from how I'd use it.


- Andrew

 

but nitrogen psi isn't the same as compression valving.


- drew

 

not altering valving, changing nitrogen psi. It's funny that no one here uses it it's been done in racing for years. I guess during all the years of building Penske and Ohlins I havent learned anything so I guess Andrew, since you say it wont work I will not be building them except for my friends. You need to read what I have written more carefully I never stated that I was changing valving, I wrote compression values ie. spring rate. No different than a remote resi Penske which psi has been used as a tuning tool for years.

 

Relax, you confused us at first because you just said compression valving and didn't mention nitrogen. Didn't mean to step on any toes.

Most people here don't use this feature because it's only available on things we can't afford. More power to you if you can make it available to more people.

Anyway, we (especially my boss Myles) know a thing or two about Motons, AST Racelines, etc. and other dampers with external canisters + the ability to add/remove nitrogen.


Good luck with the project.


- Andrew

 

This was going to be a 125.00 option on new Apexis N1's, and again I never wrote anything about compression valving. Then Miles knows the value and ease of not having to tear down a car to change springs to fine tune a combo when a few psi will do the trick. I'm relaxed just tired of getting slammed every time we try something new to this forum. Thanks

 

You're using terms that cannot be used interchangeably. ie. spring rates and nitrogen charge, compression and spring rates, using rebound to control compression, "light" psi springs... it doesn't make any sense.

I do understand that altering the pressure of the nitrogen charge is used often to alter the performance of the shock, but to say it changes the spring rate is misleading.

 

To address your comments: (1)you are correct spring rate does not equal nitrogen charge, however it does change the feel to the driver. 50 psi is equal to about 15 lbs of spring change in what a driver will feel. (2)Compression and rebound forces will change with an increase or decrease in nitrogen charge ie. the higher psi the compression forces move up as the rebound forces decrease, the lower psi increase the rebound forces and will lower the compression forces for a given valving.(3) A lighter lb spring ie. 6kg will react quicker than a 8kg spring. This is just another tuning tool for quick changes at the track to fine tuning a given combination without removing the springs.

 

It seems like you'll just be playing around in the statistical noise. With the 700-1000 lb springs that many competitive autocrossers and roadracers are using, you're talking about a 1.5% change. 50psi is a big jump in nitrogen charge, but 15 lbs is very small bump in springrate.

Even a lot of very, very good drivers are not going feel the difference. Maybe the situation is different in drag racing because of relatively low rates. Maybe there is a case of rally setups that require very low rates and enormous amounts of travel. I just don't see how it can effectively be used for autocross/roadrace setup unless you have staggeringly big range of charges pressures (100 - 700 psi for example).

d

 

Shock psi has been used as a tuning tool from USAC midgets to Indy Cars. Even an inexperienced driver will feel a 50 psi change, most will feel even less of a change. It's not the actual spring rate change, it's what the driver interpets as feel. Edited post #1 for clarity

 

I know all of this. My point was that you can't compare anything in that continuum of midget <--> IRL to an Evo. The Evo is so much heavier. I'm just skeptical that you'll notice a difference unless you make a really, really, REALLY big charge increase. At that point, changing the springs is just easier.

I await your testing results.

d

 

How about a Nextel Cup car I believe they are heavier than an Evo which I have built shocks for. If Tony Stewart can feel 3psi on a 3000+ car I think that says enough. Thanks

 

Again, my original point. I'm not tony stewart. Are you?

d