Just curious... does one have a distinct advantage over the other?
I have the general understanding that monotubes have a shorter stroke and tend to run a little harsher than the twins. And Twins have a longer strcke and more oil in them, which tends to make them run a little smoother. From an autocross point of view, assuming you've got comparable spring rates, would one be remarkably better than the other?
On one hand I see the shorter stroking monotubes having the advantage in responding faster, but I see twin tubes swallowing up bad spots on the course as a helpful thing too...
Anyone tried both and found a difference?
Or is my understanding of this just way off the mark?

 

Actually you are generally in the right ballpark. The important question is not "are these mono-tubes or twin-tubes?" but instead "are these performance dampers right for my car?".

As a generality:
Mono-tubes- Shorter stroke for a given body length, very likely a harsher ride, better potential for reactiveness over a shorter distance, better cooling (although heat really is not likely to be a problem), less liklihood for cavitation
Twin-tubes- Longer stroke for a given body length, tends to ride better and accept harsher surfaces with a better ride quality, in many ways easier to contour valving with more low speed damping (less linear) control.

A good twin tube can be much better than a mediocre mono-tube and vice versa. Yes the mon has a larger psiton but that can be a blessing and a curse. Remember the old adage "it's not how big it is, it's how well you use it". This applys to dampers too.

KONI makes both mono-tubes (must be gas charged) and twin tubes (can be gas charged or not) and selects the design to bring the best effect out of a car. Some cars love one design, others hate one design. Some cars we will mix monos and twin on the either end to get the best effect from the given car. BMWs and many lighter weight cars really tend to prefer twin-tubes, Mercedes and some heavier cars might prefer mono-tubes but the mass is only part of it. Street cars that need a livable ride will usually be better suited to a good twin-tube whereas a racecar with an extremely small stoke range and need for immediacy and no ride quality concern with normally have a mono-tube. The important thing is that it is really matched to the needs of the car, regardless of the design internally.

Don't buy them because they are mono-tubes or twin-tubes, buy them because they are the better unit for your car.

 

Is there some easy way to figure out what might work better?
I mean, both kinds are available from various companies, but no one ever gives a reason why they chose some given design.
Any ideas on what to look at with the car to hopefully pick the better option?
The car is definately light... its a Civic afterall, but what else do you need to look into to find differences between the 2?

 

Good examples of both mono-tubes and twin-tubes in operation are close enough to each other that the answer is that these should not be the specific criteria. It is not that one is always going to be better than the other, they are just tools to get to the final product that has the preferred function.

About the best I can say it to learn what you can about suspension and make the best decisions you can. If you can be choosey, pick a company with a good overall reputation for making a respected product and investigate what they have for your car. See if it makes good sense and ask for input from others and keep it all in appropriate balance. That or get a job in the shock industry, it worked for me and I think my cars are pretty well damped.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Boilermaker1 &raquo;</TD></TR><TR><TD CLASS="quote">And Twins have a longer strcke and more oil in them, which tends to make them run a little smoother.</TD></TR></TABLE>

CRX Lee pretty much sums it all up.

But one thing I want to point out in the above quote is that, twin-tubes usually have LESS fluid in them, not more.