Advice on suspension refresh

[*thomas*]

Hi all

I have a bone stock 192BHP car that is currently sitting on it's stock KYB 'sport' suspension (shocks and springs). The car has done 60 000 miles, but I feel the suspension could do with an overhaul. In Belgium, we are very limited in terms of 'upgrades', so I don't have many options and would appreciate your input.

Bilstein B6 shocks with KYB (OEM) 'sport' springs
KYB shocks and springs
Bilstein B12 kit (so B8 shocks and Eibach springs)
Tein Street Basic 'coilovers'

The car will be running on stock R3 wheels with 225/40/19 tyres.

Thanks

T.

[craigy85]

Hi Thomas,

I was in the same position last year and opted for the B12 kit - well worth the money in my opinion!

[79398]

I have the Teins and would buy again, for the cost they are outstanding, properly Tuned to a fast road set up.

[Milos_Balunovic]

Hi Thomas,

I was in the same position last year and opted for the B12 kit - well worth the money in my opinion!

Seconded. I bought a B12 kit for my R3 ( the kit being compromised of B8 shocks and eibach lowering springs). It is a good, brand new alternative that will keep you as close to stock without going to Mazda and paying lots of money it does lower the car quite a bit, so if you need the ride height, I'd suggest maybe buying a set of stock springs and using those instead.

I do really like it, and is great for road use. If you're going to track it though, you may want to look at something with adjustability, since the B12s aren't adjustable.

Photo below shows ride height on B12s. (Using 15mm spacers front and 20mm rear also which probably makes it look a bit lower and more aggressive as you look at it )

PXL_20220707_183446049.jpg

[Milos_Balunovic]

If you need to keep it stock ride height I would go with B6 + springs that are on the car. No need to buy fresh ones (unless heavily coroded and weaker)

B6 and B8 are exactly the same shocks with only difference being the B8 comes with shorter shaft to play along with lower springs. B8 cannot be used with stock springs as it will not allow sufficient extension travel !

Personally I dont like the overlly stiff B6/8 damping on low amplitude movements. That is making the car to stif and making the rubber take all the road imperfections. Those should be absorbed by springs and not the shocks , ie it should be very lose damping for those minute vibrations (if the aim is maximum traction). All the rest of the performance is really good.

Imho if not racing and liking the oem feel, japan parts shocks are just as good as kyb and will refresh the car to a "as new" feel. That will be miles appart from an old tired shocks and oil in them....

[*thomas*]

These have all been some very usefull comments, but since there is no 'wrong' it's become even more difficult to choose...

The B12 kit looks really low and might end up looking silly w/o wheels spacers (we can't use those either in belgium) and I really want to stick to the r3 wheels...

[craigy85]

If it helps, this is mine with the B12 kit and no spacers.... personally I think its just right - aggressive without looking 'slammed'

[Milos_Balunovic]

.....

The B12 kit looks really low .....

But comes with a TUV papervork so you can legalize it (the lowering of the car) and have it written in to the cars reg sheet. Unlike Tein for example.

[Leck3000]

If t is of any interest I am selling my stock R3 suspension which I believe is a little lower and stiffer and would presume that there would be no issue with TUV?? I can also send to Belgium quite easily.

[*thomas*]

But comes with a TUV papervork so you can legalize it (the lowering of the car) and have it written in to the cars reg sheet. Unlike Tein for example.

The Tein Street Basic kit does aswel come with TüV paperwork. Just need to pay the Belgian authorities 75€ so they will convert it to our GOCA certificate.

Problem with Bilstein is that I need to know if they mention CC on the paperwork. If it's 1308 and 2600cc, that ok, if it's only 2600cc, that's an issue.

[Conan]

Hi Thomas,
Some good advise from Milos
It really depends if you want twin tube or mono tube design
I would go for the Bilsteins
Regards
Pete

[*thomas*]

I would go for the Bilsteins

One of the best forums when it comes to genuinly, good advice.

Would you choose the Bilstein eiter way (B6, stock springs and B8, shorter springs)?

[Conan]

Hi Thomas
It’s not a dead simple answer as different people want different things so I’ll try to explain a little.
The standard RX-8 has very, very long travel on the suspension for a sports car so it does lean over considerably when cornering and can oscillate a little on the front at high speeds as the components get older.
To make it more of a drivers sports car feel you would stiffen and shorten the stroke slightly.
As you want to refresh your suspension I’m guessing you want to enjoy a drivers car
You have two basics types there : twin or mono tube
The Teins are twin tube design which are quick and cheap to manufacture and are not rebuildable although in theory you can get another unit to fit in the outer casing. ( personally I would throw these in the bin ) although some people’s opinion may differ
The Bilsteins are mono tube which cost more to manufacture and are completely rebuildable
Bilstein have a long reputation and when Mazda gave Prodrive 800 RX-8’s to breath performance on they gave Bilstein a specification to produce the suspension for the PZ limited edition
Mazda then continued to use Bilstein on the 40th and R-3 for a reason
I consider the PZ suspension to be the best plug and play for the RX-8 and organised over 40 K,s worth of order of this suspension for the club.
Sorry for the long post, I’m guessing the short stroke shorter spring is the set up your looking for to enjoy the car how it should be. Or just the standard Bilsteins.
Good luck
Regards
Pete

[Milos_Balunovic]

The blisteins can be very easily modified to mitigate the issue I mentioned. I suppose mazda requested simmilar mod

[RenesisRaceBuggy]

I don't think many people here will be opening their dampers and changing out face shims on the piston, however.

[Milos_Balunovic]

The shaft has to be drilled through to "connect" the chamber above to under the shims . But yes not an everyday "job"

[RenesisRaceBuggy]

Eh, that's just a bleed adjustment, that's nothing to do with high speed damping on jittery potholes, that's just dropped the low speed body control. Bleed is not a good damping mechanism it's just a required one to cure instability in the damper itself.
You've 'cured' it just by dropping the entire damping curve slightly but that's really not a good way to do things at all.

You shouldn't even be doing that on Billy's that what the shims with the cutouts are for you just change to one with larger detents.

What you've done has made far more difference to the body control on high amplitude movements than it does to the low amplitude movements you were complaining about.

[Milos_Balunovic]

not low amplitude as in mm movement but in speed of the movement.
also that small bleed hole cannot flow enough for any higher speed and becomes as if non existing (to my understanding)

I didn't get the Blis for the fell they provide , and vent twin tube instead. Not on my car. but on many others very successfully.
cannot find the exact video but from this guy.
https://www.youtube.com/user/SuspensionTruth

[RenesisRaceBuggy]

Ah, low velocity.
Yes that's the entire point of having digressive damping in the Bilsteins, it's what their performance and reputation was built around initially.
What you want to change there is soften the nose where it cracks the shims to mid/high speed instead.

Either way there's no need to drill the piston and you really shouldn't do that anyway because then you affect the rebound more than the compression and take away the effectiveness of the digressive setup. Change the shims, that's what they're there for.

Either way, modding them isn't the difficult bit, oiling, bleeding and then regassing them is and well beyond the scope of 99.9% of people working on cars.
Hell I do damper work for many motorsport teams because it's beyond *their* scope too.

[Milos_Balunovic]

On my bike (pretty much a race setup) i need to get the rear shock with external chamber (hose conneted) serviced as its "old" and im not looking forward to it at all.....

[*thomas*]

I still haven't refreshed/updated the suspension giving me to much time to think about what I should do. At the moment, I'm considering just changing the shocks to a Bilstein B6, but if I would like to upgrade the springs to Eibach, I would have to change the shocks again to B8 since these were designed for 'lowered' cars.

However, my RX8 came with 'sport' springs from the factory so I'm wondering if I could get away with a B8 shock or would this compress the OEM sport spring way to much and make the ride stiff and dangerous?