Guys,
first and foremost you need to figure out what uses are you planing for your Fit. Are you daily driving(DD) it only, or do you plan to AutoX or track it on weekends? Or is it a weekend track car only!
Here is the book sized edition!
#1 get Progress rear sway bar to reduce understeer. Sway bar will increase rear ratio in cornering only, so comfort won't be affected at all!
To understand anything first please distinguish between these two terms: spring
rate and front to rear spring
ratio!
Rate is how stiff springs are(comfort level), while ratio is balance between udersteer and oversteer.
If you do not won't to drop your car much, do not worry about it for a moment. I will explain why down this post!
I am talking springs only and as I stated before even OEM springs would benefit greatly from adjustable dampers.
On a smallest budget:
If you are only DD pick the softest/closest to stock possible set up from the stiffness chart! You will still gain a lot of cornering ability, reduce body roll to a minimum and still keep your significant others riding in the car happy. In this category Progress wins hands down since they are by far most affordable.
If you are going to AutoX, pick something with the highest rear to front ratio from the chart (2.0 or higher) to get you as much oversteer as possible. In AutoX on front wheel drive car when rear starts sliding in the corners you will floor it instead of braking to straighten the car up! Braking will produce slower times! While DD, throw a case of water or some other ballast to soften rear end to satisfy passenger comfort. If Progress with a ratio of 1.25 (BTW, same ratio as OEM springs) and a rear sway bar still understeers(according to EXWRX), you need springs with a ratio of at least 1.50 or higher and a rear sway bar! Without rear sway bar you need to get a ratio of 2.0 or higher for sure!
I do not know at what ratio, with or without rear sway bar, Fit has neutral balance (in between understeer and oversteer)! I would like to know, so if you AutoX or drove on the track please let us know!
In general, if your AutoX set up still understeers, inflate rear tires to a maximum allowable pressure as posted on the sidewall of your tires. From there, if you gained too much oversteer keep drooping rear tire pressure 2psi at the time until you achieve desired balance.
Personally, on a front wheel drive, I like to be able just to lift of the gas in the corner for the rear to start sliding wide. How much lift off depends on how tight corners are! The tighter the corners the more oversteer effect I prefer.
On higher to unlimited budget:
#1 You can pick something with stiffer rates from the chart and throw more ballast on the back, or have spare softer rear coils and change them in 10 minutes with a floor jack and a single wrench!
#2 Get Ground Control coil over sleeves kit (or put a sleeve kit together yourself-more on it latter) and pick spring ratios you can live with.
#3
Ultimate comfort with ultimate handling: same as #2, but source out tenders (helper springs) from Eibach or H&R with rates about 20lbs/in softer than OEM spring rates!!! I am not talking about the type of helper spring that collapses under the weight of the car (20-50 lbs/in rate) and prevents main spring from popping out when you lift the car of the ground! I am talking about tender (70-90 lb/in front & 100-130 lb/in rear) springs that would actually provide 1-2" of soft comfort travel before stiff main springs start working! This is what only Kg/mm brand managed to pull of in a single coil by combining two distinctly different spring rates by altering wire thickness! I have personal experience with this brand and still have them. This is also how Carrera Cup, touring cars and others solve handling on bumpy tracks. It is expensive proposition (each tender is $35-55 MSRP and you need 4 of them plus adapters). It is the ultimate set up even with adjustable dampers hands down because not even tracks are that smooth as you expect them to be! You will climb curbs on track!
Sample of motorcycle triple(!) spring set up:
Collapsible helper springs on top, soft comfort coils with travel in the middle and main race stiff coil on the bottom.
Now about height adjustments on springs that are too low for your taste.
It will cost some money.
If you would like to spend a minimum there are "spacers" in thickness from 1/2" to 2" or higher. They are either to be installed between a spring and top or bottom damper perch(these can also be made out of metal) or within coil itself(rubber or polyurethane only). If they are dual grooved so springs sit in them nice and you should squeeze them between "dead" coils on your springs. You know the part of the spring that coils are completely compressed while weight of the car rest on the tires. This way you gain height without affecting spring travel and performance. If you put them wrong, between "working" part of the spring you will eliminate spring travel and have a ride as if there are no springs and dampers on the car.
DO NOT GET "TWIST IN" TYPE METAL SPACERS OR SOMETHING THAT LOOKS LIKE IGNITION WIRE SEPARATORS. THEY WILL DAMAGE SPRINGS AND/OR FALL OUT! THEY ARE NOT SAFE!
YOU NEED FULL 360* SUPPORT BETWEEN YOUR SPRING AND A SPACER!
Sample inserts:
Top or bottom perch at spring end(note a "step" to accommodate end of the coil end which is what Fit coils have)
Below: in between coils type insert
Expensive way is to get threaded coil over inserts from Ground Control or from Koni, Bilstein, AFCO,.....
Sample:
Coil Over Sleeves - summitracing.com Use part numbers to hunt for internet bargains!
Buying a coil over kit on e-bay might be the cheapest way, but they are not the best quality and might rust.
Sample pic of Skunk2 coil over kit:
IMPORTANT for coil over sleeve kits: Front kits: For sleeves that "rest" on the top of the damper body where rod protrudes out, measure length of OEM dampers from bottom spring perch to the top of the damper body(where rod protrudes out)! Sleeves come in different length!
For sleeves that just sit on the bottom spring perch, just pick sleeve length that can raise car enough to your taste. Rear Fit kits and some front Fit kits.
Kits are universal so measure damper body diameter and/or perch diameter!
At the end I am surre I confused as many of you as I helped with more info and choices. Oh, well as long as I helped somebody.
Ivan