GE8 Fit Rallyross Suspension

I'm running a 2009 Honda Fit in rallycross. I'm running in Stock Front for the time being. Only think I've done to the car so far other than maintenance is slap on some mudflaps and  a skid plate, replace the catback with a stainless Yonoka unit as the stock one was rusted to hell (thought it was gonna fall off lol), remove the front sway and stick on some snow tires. The front sway removal was needed on this car, because it was stiff enough that I kept spinning my front inside wheel just driving around town in the rain without trying.

Next year I'm planning on bumping up to Prepared. I'm going to install on of the Mfactory gear type diffs. There is a Cusco available for this car, which I know would be slightly better, but I like the simplicity and bulletproof-ness of a gear type.

Currently, on the sock suspension (with 60k miles on it) and with the front sway removed, the car handles fairly well in terms of balance. Both on pavement and dirt, it's easy to rotate the car with left foot braking  and easy to modulate. The problem I'm having is I feel the stock suspension is too soft, especially without the sway bar. I'm cornering on my bumpstops, and then when I hit a bump midcorner I'm out of travel and basically crashing into it and bouncing wide and/or losing a lot of momentum. A feel like some extra stiffness would help out with the slaloms too. Additionally, some front roll resistance would be nice so I'm not dragging my front outside bumper through the dirt all turn, in some places I'm digging enough to actually lose a significant amount of speed lol.

I want to stay around stock height, optimally a .5" lift or so. But I'd be fine losing up to .5" as well. I don't mind scraping but I don't want to be too top heavy, or too low.

The stock springs are somewhere around 1.64K front and 2K rear. The soft a spring rate up front probably explains why they had such a stiff sway from the factory.

Some courses locally have sections of tarmac, some are on rocky ground, some are on hard packed clay, and some are on softish soil that ruts deeply. We also have a few baby jumps once or twice a year.

Current options I'm considering are:

KYB Strut Kit - I know people like the valving of the schocks for rallycross, and the spring is probably 10% stiffer than stock. I don't think the spring will be stiff enough, but maybe the improved dampening will keep the compression down a little?

Bilstein PSS B14 - They come up to around stock height, are probably about right on spring rate (5k front 3K rear I believe), and they look like the will have more travel than a typical coil over set up with a 2.5" spring. I know they will be tough because they're Bilsteins, what I don't know is how appropriate the dampening will be. I'm worried that road based shocks may have a little too much rebound dampening and not enough compression, causing me to jack down and not drop the inside tire fast enough.

Ground Control Kit - I'd probably pair this kit with the KYB Excel shocks (hopefully they'll last with the stiff spring). This kit looks like it will preserve suspension travel based on the spring design. I'm worried about the front maybe being too stiff (internet rumors say about 7.5k), but it might be alright as long as I don't over dampen them. I also don't know how high these can go, but I'm assuming they can get back up to stock height.

KSport Asphalt Rally Spec AR Coilovers - I like the fact that they seem to have lots of travel and are advertised as being a little beefier than most coilovers and are valved to be stiff but still absorb bumps. I'm worried the springs may be too stiff at 8.7k front 6k rear. Being KSport I'm assuming the adjustments won't be great/linear, but it shouldn't be too hard to find the sweet spot, wince with the high spring rates I'm going want them to be slightly under dampened.

Another thought I have is to buy a random lowering springs that look like they'll have some travel and are bit stiffer than stock, and use spacers to put them back up to stock height. I'd pair those with a KYB Excel shock as long as they weren't too stiff.

Anyone have any input/suggestions/ideas? Apologies for the long post. I know the basics of suspension tuning, but I'm new to this whole dirt thing so I'm kind of lost and there is a lot of conflicting information out there.

Thanks!

So I'm not saying to buy it, but Honda offers a B-spec Rally kit for the Fit which appears to include HotBits coilovers- if you can find out what the spring rates are that would be a good starting point.

¯\_(ツ)_/¯ said:

So I'm not saying to buy it, but Honda offers a B-spec Rally kit for the Fit which appears to include HotBits coilovers- if you can find out what the spring rates are that would be a good starting point.

was going to be my advice as well

¯\_(ツ)_/¯ said:

So I'm not saying to buy it, but Honda offers a B-spec Rally kit for the Fit which appears to include HotBits coilovers- if you can find out what the spring rates are that would be a good starting point.

Interesting. I do feel like that setup is a bit spendy for a local rallycross car. But it's a good call to see if I can find the spring rates.

Do you know anything more about the hotbits coilovers? Just googling, it seems like they used to be popular but they're kind of fading off the market and only making limited applications.

In reply to Sven :

I had a set on an FC RX7 that I rallied- in general, the performance was OK for stage rally but the durability and consistency wasn't as good as the big inverted Bilstein stuff and similar.  I'd put them above Ksport and Tein but below every other name brand rally coilover.  I wouldn't buy them for rallycross, but I would totally copy Honda's spring rate choices and find a halfway decent strut to make a rough equivalent if I were in your position.

Or, for a cheaper alternative, maybe figure out what the gaps between your stock springs' coils are and try some spring rubbers like these to stiffen things up a bit- I did that on a couple of rallycross cars with halfway decent results.

Put the sway bar back on, and lower the rear suspension without making it stiffer.

I like stiff front suspensions because you can really bomb into a corner without running out of suspension travel.  On my S40 I kept the front bar and doubled the front spring rate, and ran adjustable rear shocks set to full soft, and it was amazing.  The only thing that sucked besides it being a heavy car (2800 or 3000lb depending on who you believe) was the lack of any kind of front diff at all.  Also it tended to boil the power steering fluid, but this was before power steering coolers were allowed in Prepared.

Look at the suspension motion and tire deflection, and this is with a sway bar and 200lb springs.  If you want to make grip the suspension has to be able to deal with it.

If you didn't have a beam in the rear I'd say remove and throw away the rear stabilizer.

Pete. (l33t FS) said:

Put the sway bar back on, and lower the rear suspension without making it stiffer.

I didn't think about it that way. If I'm picturing this right in my head, it looks like by lowering the rear a little, that inside front wheel should stay down better.

I suppose I'll start with your suggestion, putting the sway back on and lowering the rear a little. If I'm still having inside wheel lift problems, I'll try stiffening the front to reduce compression on the outside wheel, and hopefully keep the inside one down.

If I can't get the car working right that way I'll look into doing something else.

In reply to Sven :

A Fit is a modern, Japanese Golf (and I mean that in the very nicest way, I drove a Fit Sport home tonight and the handling dynamics remind me a lot of my Golf but better) and one thing that paid huge dividends for rallycrossing the Golf was 2" Neuspeed lowering springs on the rear.  They definitely helped keep the inside front tire on the ground.

The funny thing about dirt is that for unpowered wheels, increasing weight transfer will increase grip.  So stiffening the rear will make the car understeer more, not less.  For powered wheels you still need to worry about keeping them planted so that you can put power down, which can be at odds for generating best cornering loads.  It's an interesting problem and 4 people will have 5 different opinions and all of them will be right.

Oh, I should point out that I do NOT left foot brake.  I treat braking and accelerating as two separate functions, if I need to rotate I do it on corner entry.  This is where the stiff front comes into play.

In reply to Pete. (l33t FS) :

what about using the hand brake to rotate

In reply to MrChaos :

Hand brake makes you slide, though. Sliding is slow.   I think of "rotating" as getting the front end to go into the corner faster than the center of gravity does.  I don't want to back end to come out, i want the front end to go in!  That's where the corner is.

I have a handbrake in the RX-7 but rear drive is different.  Both are the same in that you steer by where the drive wheels are pointed, with a front driver you have this big round thing in front of the driver to point the drive wheels but for a rear driver you have to get finesse-y and point the car around instead, and for some maddengly slow corners you can't get enough inertia to get the car pointed in the right direction to be able to apply power.  So it is more a crutch for not having enough power to be fast.

I have heard honda makes it very difficult to get their suspension setup they offer.  This was from a fellow rallyx'er that uses an RSX.  

I just had an epiphany about Jean Ragnotti's flamboyant driving style.  He gets the car way crossed up sideways before a corner, because that gets the center of gravity further away from the front wheels (relative to the axis of motion) so that the steering is more effective.  And he usually balanced it well, looking at his steering inputs.

Not that this has anything to do with rallycross, which generally happens at 20-30mph and on rough loose surfaces instead of smooth tarmac.  But I think the effort should be made to move as much weight as possible back, to get the cg further away fron the steering wheels, so they can exert more leverage on the chassis as a whole.

is a LSD in a fwd car an advantage or disadvantage in rallycross, wouldnt that lead to much more understeer?

MrChaos said:

is a LSD in a fwd car an advantage or disadvantage in rallycross, wouldnt that lead to much more understeer?

Pete can probably answer this better than I can, but it's a huge advantage.

In a FWD car with an open diff, the inside tire will have so little traction that it will spin and all the power will go there, and very little power will go to your outside wheel which is stuck in the ground. You don't have the same level of mechanical traction on on dirt as you do on asphalt, so you need the drive tires to pull you through the corner. LSD helps a lot there. I'm sure there is some debate on 1 way vs 2 way, but in general it definitely helps.

In a RWD it helps as well, helps put the power down to get the back to rotate and help you keep a more consistent slip angle. But as Pete said, turn in in a RWD is a little more complicated on dirt; you really have to work to get weight on the front wheels.

What are some tricks or solutions to get some extra ground clearance on a Fit? I scrape mine easily on driveways sometimes.