Suspension

[Zedrally]

Who's using what??????

I fear I don't have the best setup as I keep "stuffing" the front shocks.

Once more on Saturday night, I collapsed both fronts. It was an easy night, no fast belting around in the bush either.

For want of better words! Needless to say I'm starting to have grave reservations about the setup.

I presently running Konis in each corner with a modified 2.5 inch spring on the front struts.

What advice can I glean from the experts?

TIA:(

[XYZ]

When you say modified springs on the front what does that mean? Are they stock springs that are cut down or are they aftermarket springs? Also, what are you using the car for? Maybe you don't need a setup quite so extreme. I personally am running non adjustable tokico's on Eibach springs. My car lowered about 1.5" from its original height and is running fine.

[Zedrally]

Obviously having posted this in the Rally forum, thats the use of it {rallying}.

Certainly lowering is NOT an option in this area of the sport, in fact if anything we need an extra 1'-1 1/2".

The springs have NOT been shortened, they are just a smaller diameter spring to accomodate wider rims.:stupid:

[XYZ]

Sorry- just saw this post on the latest discussions didn't realize it was already categorized ie...in the rally forum. Don't know anything about rally racing so I'm not much help. I was hoping to help keep your thread alive. For what it's worth!

[Doehring]

Zedrally,

I have the same set up as XYZ because I mainly drive on tared roads here. For special stages off the tared roads I would also try to get the car higher, as you said. At first I would take the original springs in turns and length, but stiffer, if available. In every case I would install urethane bump stops to be protected against the hardest shocks after jumps. Why do you need larger rims on these roads ? On the "roads" you mentioned earlier I would take the original alloy rims from the

early 280 ZX (5,5 J I think) with 195/70-14 tyres and M+S (Mud and Snow) or similar block profile. This brings more grip on gravel or mud, the tyres have a bigger diameter (what brings the car another 2-3 cm up) and they are softer when landing after a jump. The profile is also a better protection against sharp stones on the track. The acceleration may suffer a little, top speed might rise but normally these tyres are not for top speed but fast enaugh to "play with the music", as we say here (means: to be within the top)

Rolf

[HS30-H]

Hi Mike,

I don't think that you will get too far with oil-filled damper inserts like the Konis. The pounding that they get on even a fairly gentle rally stage just overheats the oil and it starts by-passing the valving, effectively giving you hardly any bump or rebound resistance.

Oil-filled is OK for street or even smooth circuit use, but over here in the UK the serious Historic Rally Z racers all use gas-converted struts from the likes of Bilstein. They have much beefier rods and quite fundamentally different internals, but they look pretty much like the factory Rally struts. None of the racers will be too forthcoming about their bump and rebound rates ( you might have to try and find this out for yourself, as knowledge is power in their eyes! ) but the main point is that the conversion to gas will stop that situation where you lose all shock effectiveness after just a few miles of stage.

They all tend to use the 2.5 inch springs on adjustable platforms, simply for the wide choice and cheapness of springs in that diameter. I don't know anyone who uses them in Historic Rallying so that they can get extra wheel / tyre clearance ( they are all on pretty skinny rubber ).

The Works rally Z's all had gas-filled struts and adjustable platforms, but with the stock diameter springs.

I think if you contacted Errol Smith at "DATRATS" in Victoria, he would be able to advise you on a gas-filled conversion that would transform your car. Do bear in mind that getting it right is not cheap, but this is a fundamental part of making a good rally Z.

Good luck!

Alan.

[Zedrally]

This is great guy's.

I probably should clarify why the springs, originally the idea was to have a setup that could be used on the track, autocross, tarmac rally and forest rally.

I now realise that is impossible in one car and having enjoyed rallying the most, I intend to develope the car in this area.

Looks like there will be a set of Koni's on the market here.

Thanks again, you both have pointed me in the right direction.

[hmsports]

I may be interested in your Konis - what model are they?

[Zedrally]

Don't get your hopes up hmsports...yet. I still have another Zed with original suspension and would like to complete the collection with a 260 2 seater.

Thanks again for the assistance, I'm inclined to go for Bilstein's as suggested. Although, I can't help feel that Koni's with a stronger spring might be a solution?

The Bilstein option opens Pandora's box...

Are there different types of Bilsteins? If so which is better suited to the Zed and forest rallying?

Do I need adjustable platforms or can I go for 15" rims for extra ground clearence?

What would be a suitable spring to start with?

TIA for any advice that you can help me with.

[Doehring]

Zedrallye,

yesterday I read that the later 240 Z got stiffer front and rear springs stock, in front much stiffer than at the rear. The result was that the car became a bad understeerer. to solve that problem Datsun built in the rear swaybar. So: If you can get the stock springs of that year when Datsun made the rear swaybar stock you have the stiffer springs you are looking for, may be now you need a rear swaybar, too. By the way, do your rules for historic rallying allow 15' rims ? I think 7J-14 was the biggest homologated wheel.

Rolf

[Zedrally]

Our rules allow 1" over standard, most 240/260's out here run 15".

The rear sway bar is from a 260. I'm heading out in an hour or so to see the expert, so I',, keep you informed of what they suggest.

[HS30-H]

Mike, you need adjustable platforms with LONGER springs - not necessarily all that highly rated though.

Your shock absorbers / dampers will not work unless they have the opportunity to do so ( i.e. via travel ) and therefore the springs don't want to be all that strong. I would not recommend going over a rate of 230lb for a Rally car, and judging by what the Historic Rally Z guys here in the UK use, I would advise you that the crux of the matter is the valving in the GAS dampers. You have to get the bump and rebound rates right to make them work properly and allow you to drive the car, rather than it being controlled by the spring rate.

I only quoted BILSTEIN as they seem to be what they are using over here, and there must be other companies who can make the same kind of thing. I want to make sure that you understand that they are using completely new tubes, rods and valving; in fact they seem to cut off the original tubes on the legs altogether and fit a complete new tube with all the stuff inside it. This is NOT CHEAP!

Don't think that this makes for a purely "Rally" set up that is not useable on tarmac. Quite the opposite is true, and with the adjustable platforms you can simply wind the ride height of the car up or down as you like it. I have driven a Historic Rally Z with this type of set-up on the road, and it felt absolutely different to what I am used to. It felt like it was being controlled by the dampers ( rather than the springs ) and was stiff without being harsh. I felt like I could be a real hero in this car!

So, that's what you need if you are going to be serious; a proper gas set-up. I know a couple of specialists here in the UK who would make a set of legs up for you if you can't get them in Aus. I could get a quotation for you if you like. That might be interesting.

Rolf ( Doehring );

the rear anti-roll bar was standard on all S30-S, PS30, PS30-SB and HS30 models right from 1969. Only the poor old S30 and of course the HLS30 didn't get them from the get-go. Seems they thought the "poverty" model S30 and the USA / North American market version owners would not be interested in going around corners!.................

This means that Mike's car ( as an Australian market HS30 ) already had a rear anti-roll bar. Sounds like he upgraded to an RS30 rear bar for extra beef.

Alan.