Does anyone make a set of coilovers that have a external reservoir I have a pic of a apex turbo and behind the turbo is a coilover with a reservoir I want a set already setup for a fd3s.I am using my car for autocross.I dont know if anyone has messed with penski shocks.They are nice.But I dont know what spring rates to use.

 

If you have to ask, you probably aren't a good enough driver to need them....

If you are serious, give Tripoint Engineering a call, they are FD auto-x gurus and can help you with advanced suspension setups.

 

You could always buy the Penskes in the 3rd Gen Parts for Sale section. I believe those have remote reservoirs, and the seller sprung for triple adjustables...

 

God I saw those the other day, wish I had $4500 to buy them.

 

The main reason for having the external reservoir is for controlling the temperature of the shock oil. Generally not necessary on anything other than a race car which run for extended periods of time at race speeds. It's definitely not necessary for autocross. The external reservoir also adds another point of failure with the added connections to the tank.

Mark

 

i beleive Aragosta Tein and Quantum have oil reservoir in their top race coilovers. buttttttttt it all comes down to $$$$

 

All the systems I'm familier with use a remote reservoir because there are additional valves placed in the reservoir. On a truely double (or triple etc) adjustable shock you need to have adjustable orifices both above and below the washer stacks on the piston. As a side benefit the reservoir also allows gas pressure in the canister to be easily changed so the options of valving are nearly limitless. When you start doing things like adjustable low and high speed bump along with low and high speed rebound you must have a remote reservoir because you can't incorporate all that adjustable valving into the shock without making a very ungainly looking shock.

The remote reservoir can be located anywhere convenient. Whether that be a canister connected by a hose to the shock body or the canister being carried right next to the shock body on a bracket.





Something like a Koni yellow or Tokico adjusts by controlling the size of the holes in the piston between the washer stacks via a rod that extends through the piston rod. The fewer the openings in the piston the stiffer the shock in both bump and rebound. The bump vs rebound rates are not adjustable though because in this case that is determined by the washer stack only and their comparitive rates are fixed (Unless you change the washers. That's how you "revalve" a shock). When you convert a Koni or the like to double adjustable you add an adjustable orifice behind the piston that allows you to adjust this valve independently of the washer stack. From there you can keep isolating more speed situations on the washer stack and running additional valves to control other aspects.

Here's a good pic that shows what is inside a typical shock. The far right shows the piston and washer stacks. As oil is forced through the piston the washers "blow off" and allow control of the restriction on the orifices in the piston. Shocks with external reservoirs are plumbing additional valves above and/or below the piston to allow even more control of damping rate vs piston speed.

 

Yes, absolutely correct. I didn't mention that the external reservoir also gives further adjustment possibilities. A better statement on my part would have been: A reason, instead "The main reason"

A good basic source of info is available from Ohlin:

http://www.ohlins.com/pdf/07255-01.pdf

Read in the design notes and you'll see mention of the added benefit of heat reduction in the use of an external reservoir.

Mark

 

Good stuff. Thanks!

 

I forgot to add the pic of the apex coilovers in the back behind the turbo

 

Check out the pic