Go Tuning Unlimited

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Very nice, looking forward to the rear plates

 

+1. Now if you can make camber plates for the front to get rid of that nasty positive camber.

 

Huh?

Where would you put plates in the front? Are you talking about some kind of adjustable coil overs w/ plates at the top hats like a Civic?


Your car has positive camber? Mine was at 0 before I put neg in w/ bolts.

 

You can use camber bolts

 

Sometimes I just can't let something I've seen go without comment.

Unless you are actually racing, with competition tyres and ultra-stiff rear springs (which means it won't cope with the ordinary bumps of everyday driving) any sort of stiffer front sway bar will make your Jazz/Fit much worse to drive, and is a complete waste of time and money.

Having just been through an exercise to turn our GD3 from a horrible, bouncy, understeering disaster of a car into something I can actually enjoy driving, I can be absolutely emphatic about one thing - a bigger front bar will NOT help with turn-in. It turns out that the JDM GD in stock form has bump stops both front and rear which are far too long. The springs and anti-roll bars don't really get a chance to work. Removing the front bar did far less than I expected - while it did reduce understeer a bit, and make the car more comfortable in a situation where, for example, you turn slowly into a driveway diagonally across a gutter, the rear is virtually sitting on the stops and the front is not much better. The shocks can't cope with the stiff rates of those bump stops. (And of course any attempt to fit lower springs would have just made matters much worse.) But you can't see the bump stops, they are inside the springs, hidden inside shrouds.

Front struts out, springs off to find the front ones; and rear shocks out and drill out the crimp on the top bush crush tube to get at the rear ones. Cut the fronts down from 90 mm (!) to 38 mm, and the rears from 115 (!!) to 55, and suddenly I had a car that was actually perfectly pleasant to drive. Still understeered though...

And now some stiffer rear springs have brought it to life. (10" race coils, 2 1/2" I.D., about 330 lb/in or 6 kg/mm. A straight fit.) Sharp turn-in, body roll quite acceptable, balanced handling, understeer basically gone and if needed it will tighten its line nicely mid-corner, which it simply refused to do before. And no front bar at all - for ordinary road tyres, it doesn't need one because the front springs on this model are actually reasonably stiff. But the new rear springs are too stiff for comfort, especially without a load in the back.

I knew all along what was needed - a decent rear sway bay. The U-beam itself provides next to no roll resistance, and the tiny 19 mm welded inside it is just as ineffective. Instead, 25 mm would be about right - or perhaps add an extra one bolted to the spring seats - about 22 - 23 mm like the Progress one.

I have driven a GE Jazz and they are worse than a GD. Softer at both ends (Not sure what the JDM Fit is like, nor the USA version.) I had a look at the suspension and made some measurements and calculations. Everything is different to the GD - the spring positions and geometry - but the principle is exactly the same. This time the front isn't ridiculously stiff. Instead the rear is ridiculously soft.

And recently I looked at a very new Jazz sold by Honda New Zealand as an "RS". (Which used to mean Rally Sport). I just looked at the miniscule rear bar, beam and springs and laughed. What a waste of space...

Simple statement of fact: A FWD car needs more roll stiffness at the rear than the front.

What's so hard to comprehend about that?

 

It's good advice Croc and it seems to be echo'ed in the Sway Bars thread. Thanks for the post.

 

Robertsmithfromthecure, have you read my rather rambling posts at the end of the Suspension Theory sticky? I'm hoping they make sense, and I want to add some more detail but it gets quite complicated. It's hard to make it both comprehensible and technically accurate.

 

hmm beefier front sway bar...Anything to soften the major body sway is a win win...

 

Thanks for pointing out your write up Croc. I just read the whole thing and it was very interesting, not at all impenetrable writing. It was very clear.

I am on the low end of the car enthusiast spectrum - more concerned with looks. I won't be racing it. However I would like a car, "with impeccable road manners" as you say. I really enjoy tossing it around corners and zooming up on-ramps. From your advice and many many others on this site I'm going to install Swift Springs (2.5 kg/mm front and 2.8 kg/mm rear) and a Progress rear sway bar. I don't know if my budget will allow for a damper kit to change from the stock rebound/ compression.

 

you sound like us Robert...

I am awaiting next spring to get some much needed better tires on ours and see how well it does with those and the rear bar. After that we may go with springs. I like throwing it around but it is down right scary with the body rebound sometimes. I haven't a driven a car like this in a long time. So used to planted sporty cars.

Taking a ramp some ramps at 60+ is just not do-able where as our old car wouldn't sweat it.

God I miss cloverleaf interchanges in my RX8...

 

There is absolutely no doubt that the damping is the single most critical part of a car's suspension. Springs and sway bars can never work unless they are controlled properly by the shock absorbers. You've got to be sure of what the car is going to do, it's got to be smooth and predictable, before you can enjoy driving it. And my stock JDM GD was easily the worst handling car I have ever owned.

In my case, the glaring fault was that the bump stops were far too long and stiff, and were totally overwhelming the shocks' ability to control the ride. But of course you couldn't even see that until the shocks, front and rear, were out of the car and their shrouds removed.

And I don't think there is any way around it - your first step has to be to do that and measure where the shocks sit at static ride height, work out how much stroke you have both up and down, and make sure the bump stops are appropriate. Otherwise you could end up wasting a lot of money and time going down the wrong road. Lower springs, for example, would have made things much worse.

It's very hard - no, it's virtually impossible - to determine in advance what shock absorber rates are going to be best for any given situation. For this reason I've always liked Konis because their rebound rate is adjustable. If they are not available for a particular car, they can be manufactured, modified and revalved as plenty of others have noted. At a cost, of course.

A while ago I did find some listings for the Jazz from Bilstein, which is a very high quality manufacturer. But I have a feeling that they are a new, cheaper twin-tube line, not the traditional Bilstein monotube. The monotube gas Bilsteins are revalveable, also at a cost, by a shock absorber engineer but I suspect that the cheaper ones are not. But I would also suspect their damping rates will be very good.

A FWD Fit will never be a RWD RX8, of course, but with good damping and good rear roll stiffness you can certainly enjoy chucking it around. And after my little improvements I was able to do just that on Sunday. It felt good. Not quite perfect - but good enough to put a big grin on my face...

 

i never said it would be nor that I ever wanted it to be..

 

"God I miss cloverleaf interchanges in my RX8..."

Sure sounds like you have a teeny-tiny regret about it. I've only driven an RX8 briefly but it is obviously a big advance on the chassis dynamics of earlier rotaries. Certainly torquier and more nimble than my old RX2!

Trust me, good shocks and that big rear bar in the Honda will dull the pain!

I wish I could be more helpful about which shocks to use. One rule of thumb that is very rarely broken is that Japanese just don't understand shock absorbers. But whatever you fit, make very sure that you don't restrict the upwards distance the wheels can travel. Stock ride height and at least 2" travel before the bump stops make contact is a good starting point.

 

Have the plates been tested to work on drums yet?

 

Any update on the rear plates? I tried to order them just now but it says preorder still.

 

Very curious about this as well!

I'm also curious to hear if anyone on the forum is using any of the Spoon products yet?

 

I went ahead and emailed Spoon to find out if the rear camber plates will fit drum brakes. It looks like they will only fit with the rear disc conversion

Below is their response:

"Hi,

You will need the rear disc brake conversion to use the camber adjusting plate.

Go Tuning Unlimited

Both items are special order and will take 2-3 months for delivery."

 

Man, that's disappointing. I emailed GoTuning as well but no one responded to me.

 

Price is keeping me completely out of this! Although I fully recognize the amazing quality of Spoon products, 2x in price for maybe 1.1x in quality doesn't really seem fair.