ImamurA

Hi guys...I decided to get a set of the Ohlins DFV coilovers but I need some advice from the current Ohlins owners...

My car is mainly street and AutoX and I plan on purchasing a set of 18x10.5 +47 offset Enkeis and plan to run 285 width tyres...maybe I might buy R-comps in the future for race use...

So I have read that the factory 11k/11k setup is very good for stock width street tyres but some owners say that for wider and grippier tyres they would like to have a higher spring rate...

..I am thinking that the heavier combination of tyre/wheel and also the slightly wider track width would lower the "effective spring rate" of the coilovers? Is this correct?

At first I was thinking that I wanted to drive them at 11k/11k to get a feel of what Ohlins developed and then if I want I can send them back to get re-valved but the problem is that I live in Trinidad, West Indies and would have to ship them all the way back to USA to do this...

My question is, based on my planned setup would you recommend staying with the factory 11k/11k or should I get a higher spring rate? Do you think a 13k square or a 14k square would be too stiff for maintaining traction on the bumps on the street?

Thanks guys!!

ImamurA

Also I just read in the SBG thread that Ohlins USA says the factory valving is good for up to 14k without requiring a re-valve...

If I purchase a set of stiffer springs I will also have the factory 11k springs if I ever decide to put them back on...

What happens if you use a too stiff spring for the shock?...

purerx7

iTrader: (61)

11k/11k setup is more than suitable for your needs, don't forget you have the flexibility to adjust both dampening and pre-load. We have sold many sets of Ohlins DFVs to more track orientated FDs and they have been performing great on 11k/11k.

BLUE TII

iTrader: (9)

I have light 18x11 and 295 Ventus TD DOT-Rs and I have to crank the damping to near max on my Ohlins when I am on a track.

I would recommend a higher spring rate for track use with wide DOT-Rs so you don't have to try and use compression damping for the job of a spring. If you go with 13k or 14k you shouldn't need a revalve and you won't have to crank the damping quite as high.

Too stiff of a spring for the shock will cause it to have not enough rebound damping and you will get cyclic wheel movement over a single bump (loss of traction).

I really noticed switching from my heavier 18s back and forth to my very light 16s that the heavy wheel and tire really does need more spring/damping on the street to keep it from banging the bumpstops as it has a lot more inertia when it hits a bump and you are already closer to the bumpstops from more traction induced bodyroll/dive.

ImamurA

Thank you for the info and help guys!...Much appreciated..

ZDan

I'm thinking of getting 13k springs for the front. IMO, 13F/11R should be a great street/track setup. That is, too stiff for the street and too soft for the track
The standard 11k/11k is really a great compromise, but for my car (463rwhp), I wound up disconnecting the rear bar to maximize rear grip. I think that getting 13kg front springs might allow me to reconnect the stock rear bar and further reduce roll.

If you want it trackier, running R-comps, maybe something like 16F/14R.

cryomark

I'm running the DFV stock valving and have been through a progression of spring changes on the track. I started out with the supplied springs (110 N/mm or 11.22 kg/m or 628 lb/in) and the car was very well balanced but was bottoming out the tires into the tops of the wheel well on big bumps and compressions. The adjusters mainly control rebound but have some influence, I've read ~10% maybe, on compression, adjusting didn't help the bottoming at all. The DFV valving has very little compression damping to get that nice ride, but that doesn't help anything on the big hits.

I upped the front to 750 ln/in (~13.5k) and things did improve a little, but with more understeer and still smoking the tires. Next step was 850 front 750 rear. Better.

950 (17k) front 750 rear and readjusted the geometry to use the bump rubbers more effectively. Actually added aluminum washers above the front bum rubbers to space them down a bit, as I ran out of room to lengthen the damper body any more.

The car has noticeable understeer with this setup. It was balanced with equal rates f/r but going stiffer for me in the rear compromises grip coming out of the corners on the gas (555rwhp). Each time upping the rates the car was faster on the track.

I really need to get these re-valved to see if I can control the big bumps with compression damping instead of spring to bring the balance of the car back. I usually run 4-6 clicks on the adjusters to get the turn-in response to what I like. Tri-Point bar up front on full soft, '95 rear bar, 285's up front 335's back.

By the way, you shouldn't need to send your dampers to the US for re-valve. I would think there would be someone who can service Ohlins closer to you.

Hope this helps. Mark

Mazderati

iTrader: (3)

Cool looking car, cryo.