ISC-N1 Coilovers

[Guest]

what simon said..

most jap coilovers use very stiff spring rates, my R33 had 12/10's teins in it, and people behind me used to say they could see my car skipping left and right.

VERY interested to see how you go with the swaybars too simon, that was the first thing i wanted to do, but didnt want to dive into the research myself.

 

[leebutts]

2. The standard ARB is 20mm front 22mm rear. I would suggest probaby a step up to 22 front 24 rear- but i will be investigating this a little further with a potential group buy on this....

That's the specs of the Cusco bars I have on my car.

Thanks for the recommendations Simon, I'll be shopping for coilovers soon.

 

[mookers]

I have the TEIN super wagons at 5kg/3kg and they are very nice. Not too soft, not too firm. Took away the "floatiness" that the stock setup had, although perhaps that is due to the better damping. I still have the stock anti roll bars in... I can tell it would be good to get those upgraded as quick directional changes still seem to make the car feel a bit ponderous.

 

[bradc]

I've been in a VR-4 with 10kg F and 6kg R and it felt fantastic. The dampers were set quite soft though, but it really did handle and I was definitely impressed.

Simon, have you actually tried 10kg or similar springs in a Legnum with soft dampers?

 

[jungle]

Glad to be of help. I've been quite busy with work and haven't been able to call Superior Suspension- i plan to do that Tuesday and i hope to be able to provide some information for you then.

Lee, sounds like my educated guess will be pretty close- nice to know

Bradc- Legnum no. My Skyline had 12/10's when it arrived from Japan, complete crap. that spring rate is just ridiculous, again, just tells me it is using spring to control roll, and a very strong damper to try and smooth out a very hard spring- or it's a drift car that was on a super smooth track.
By the sounds of it, it may have produced a reasonable result, but its more the tail wagging the dog.

I know of race cars with 120lb rear springs- that's around 3kg's/mm

Again, its horses for courses, if those stiff rates work for you, great, i bet you are still running standard roll bars and if you're happy with it, great. I'm not here to tell you what you should have, but to point out what has worked for me and what i' plan to do with our Leggy. Having a 2 other cars with different purposes and suspension packages helps me make an informed decision and if it is of some benefit to others, then i'm happy- if not, I'm still happy.

As a side not, i run a 27mm front arb on my S13 and 22 rear.

I would suggest 27mm rear on a leggy will probably have it oversteering close to the limit, but if that's what you want- go for it!

 

[bradc]

On my Leggie I have the Cusco anti roll bars, but my springs are around the 5kg F and 3kg R mark. The car that had the stiff springs in it had the stock ARB's.

I did some high speed cruising yesterday on some NZ back roads and there were a few times when I hit big undulations and I could feel the tyres going right up into the arches of the car. Something slightly stiffer might have been better, I don't know.

 

[Kenneth]

I got 12kg / 8kg front / rear on my coilovers. (Un-branded, but same as ISC, which are just branded units)

There are a few issues to think about and you have to match the suspension with what you are doing with the car.

First off, stiff anti-roll bars, hard dampers and soft springs... Might be good for track, but I would not use it on the road.

Anti-roll bars remove the independence of the wheels which effectively adds the anti-roll stiffness to your spring rate when cornering (the outside suspension compresses, and due to the inside wheel being coupled, it has to try and compress the inside suspension as well). It does nothing to diminish the affects of a bump that affects both wheels at the same time, such as a significant dip in the road at high speed (which you don't really get on a track) the result of which can be catastrophic when your chassis and everything else grinds across the ground.
You will also find that your car cannot handle increased loads, such as more passengers.
The only reason standard suspension has such a low spring rate is because the amount of travel in the suspension can absorb much more movement without hitting the ground. If you lower the car, you must increase the spring rate, otherwise it just isn't safe.

Dampers / Shocks. I will call them shocks because their job is to transmit energy (felt as shock) to the chassis / car body rather than store that energy in the spring.
A spring stores energy and a helical compression spring is one of the most efficient energy storage mechanisms you can get. Because of this, it has to be dampened so that the spring doesn't return all of the stored energy in the spring to the wheels, which would cause the car to start (or feel like it is) bouncing.
Because of this, the damper only really needs be strong enough to reign in this adverse behaviour, it is the spring that should be doing most of the work. The problem of course is that the larger the amount of shock (which relates to how fast you hit a deformation in the tarmac) the stronger the shock has to be to deal with the spring AND the speed in which the transitions happen. Setting your shocks for high speed is going to result in discomfort at low speed, which is why adjustable damper rates are so useful.
The reason I wouldn't use a high damper rate on the street is because of the size of deformation in the road (pot holes etc). If the damper is hard, the spring ends up doing no work and instead the shock is transmitted through piston in the shock, up the shaft (which unless you are using inverted shocks, is actually not that thick), into the top hat (and take a look at how localised the connection between the shaft and top hat is... its bound to fail fairly quickly) and then into the suspension tower, into the chassis and then into your back. Ouch.
On track, these are less of a problem because the track is smooth and you can increase the damper rate so that the shocks can operate at a speed consistent to what you are travelling at and actually respond well to smaller deformations in the road surface.

Personally, I use fairly high spring rates on the street. Coupled with adjustable dampers (set low for around town driving (12%)) which results in the following ride characteristics

• smooth shock movement, low jarring
• smooth spring movement, though low travel. (only gets annoying at low speed on surfaces which are bumpy over a long distance)
• Excellent highway speed stability and up to over 200kph
• Excellent roll resistance (though I do up the pre-load to help this)
• Only time the bottom of the car touches the ground is over humps such as speed humps, fubar drive ways.
• Excellent load carrying capability, Legnum with 3 people, rest is gear (mostly booze) and the back end sunk perhaps 10mm from normal and handling was still good.

About the only time I was not comfortable was at low speed on large bumps, however I would rather be uncomfortable than hitting the ground, so I accept the trade-off. Oh, and one stretch of road where the small sharp undulations are just at the right frequency so that at the speed limit the up and down must have reached resonance on something... so I had to speed up or slow down
Other than that, I would say the ride was perfect. I will say that the car wasn't lowered excessively, that really screws up the handling.

It makes me laugh when I see a lowered car which has its backside sitting on the ground whenever there are some passengers in the back seat... A sure way to screw up the underside of the car.


All that being said, I don't actually have any experience setting up for track, so I would like to make it clear that these observations come from my use of various suspension setups on the road driving around town and on fast road areas as well as some private roads for anything over the speed limit.

Hopefully ill have the coilovers back in the Galant sometime soon and Brad can give his opinion on how the ride is with 12/8 f/r spring rates.

 

[timmae2006]

I just bought these above are for "R32" but same colors for legnum *BLING BLING* 8KG/6KG arrangement will let you all know how they go as i havent found 1 review in this thread from vr4 owner with these installed...so stay tuned let you know when they arrive

 

[Kenneth]

As I said in my post, mine are un-branded but come from the exact same factory as ISC.
ISC coilovers are produced by a Taiwanese OEM coilover manufacturer who on sells them to distributors who brand them.
I was fortunate to get a set which has no branding at all, which reduced the price considerably.

I just bought these above are for "R32" but same colors for legnum *BLING BLING* 8KG/6KG arrangement will let you all know how they go as i havent found 1 review in this thread from vr4 owner with these installed...so stay tuned let you know when they arrive

 

[timmae2006]

oh yeah totally missed that apologies.....how did you get them ones then?

 

[SiliconAngel]

....how did you get them ones then?

And more importantly, can you get more?

 

[Kenneth]

no, don't think so... The bloke I got them off was going to brand them himself, not sure what happened though as I didn't see him sell any more.

Probably wasn't the market for them in NZ to compete with K-Sport and D2

 

[jungle]

Bradc, I did reply to you mate, but for some reason it's gone missing- think it was when the site went down
Was a reasonably lengthy post but as it's been a number of days since i did it, cant remember what i said.

Short version, if you're going to drive at speed over roads that have large verticle changes in it's surface, then i hope you have good bumps stops
I guess you need to decide what % of your driving is at speed over large changes in the surface- there are always going to be trade off, you need to decide what you want your car to do.

As a side note, mate of mine runs the ISC's in his EVO9- admittedly the car has been to a race suspension guy and it set up specifically for QR, he's 1/2 second a lap fast than me. Although my car is booked on for a "once over" suspension wise i expect to go sub 57 saturday week at QR His best is 57.1- his EVO puts out around 235rwkw.

 

[Kenneth]

As an update, I now have my coilovers in the Galant. These coilovers are made by the same manufacturer as the ISC coilovers and as such, apart from the branding, the are exactly the same as the ISC-N1 coilovers you would buy.

Mine have spring rates of 12kg front and 8kg Rear.

Presently the car has no weight reduction (other than the flywheel) and so this spring rate combination is designed to reflect the weight distribution of about 60%/40% front/rear respectively.

Preload is set as far as I can do up the spring perches without using anything to assist other than the supplied spanner.

I have dropped the car probably close on 30mm. This isn't a lot and the car doesn't look like it has been lowered a great amount. The reason I didn't lower it further is because I have found in the past that the handling actually gets worse, presumably due to the suspension being outside the optimal operating parameters.

Damper settings front and rear are 4/32 and 3/32 respectively. For street use I have them low for comfort. I want them just strong enough to stop the car feeling like it is bouncing. I also want to ensure that the springs will be used to absorb bumps and potholes rather than having the shock transmitted through to the top hats and into the chassis.
With some more driving on different roads this may change, but for now 4/3 is ideal.


The result...
Comfort is very close to standard. Over large variances in the road it becomes obvious that the car isn't moving as much on the vertical plane, however there is no jarring or bouncing.

Handling is great. Very little body roll and plenty of predictable grip. When the back steps out a little it is very easy to bring it back in line with a small amount of correction.

One thing I have yet to test is the anti-dive characteristics under heavy braking.

 

[jungle]

Hey Kenneth,

Would love to go for a ride in your car to sample the suspension.

Talking of weight distribution, I put the Leggy on the scales at work a few weeks ago with a full tank of fuel + me the corners were,
FL 455kg FR 490kg
RL 345 RR 355kg

Hope that helps in you

 

[bradc]

The handling was indeed very good, I was happy with it when we went for a cruise yesterday around some tight roundabouts and corners.

 

[Kenneth]

If you are ever in NZ, you are welcome to go for a ride in the Galant

Thanks for that, gives 57%/43% front/rear. If you don't mind, what sort of weight are you?

Assuming the Galant has about 50kg of weight less in the rear, that puts the Galant at pretty much spot on 60%/40% front/rear!

Hey Kenneth,

Would love to go for a ride in your car to sample the suspension.

Talking of weight distribution, I put the Leggy on the scales at work a few weeks ago with a full tank of fuel + me the corners were,
FL 455kg FR 490kg
RL 345 RR 355kg

Hope that helps in you

 

[Kenneth]

The handling was indeed very good, I was happy with it when we went for a cruise yesterday around some tight roundabouts and corners.

I need to get some decent seats in there though, the standard non-recaro seats are rubbish.

Haha, when Jo is in the Galant she complains that she likes the recaros in the Legnum much better

It will handle better once the alignment is done and I do something about those rear tyres... I am not keen on giving it any gas in the wet around those roundabouts, it steps out easy enough in the dry.

 

[jungle]

What's up with the rear tyres?

I weigh 75kg. I have new anti roll bars to go in. 27mm rear with 4 adjustments and 24mm rear 3 adjutments. I'ts the same size as the HPI project Galant used. I hope to have them fitted i a week or so.
I have the Tein's 5 front 3 rears. Be interesting to see how they go.

I had the Leggy sideways on the dirt last night, entered a hairpin off tar onto dirt at 60km/h interesting feeling having the AWD car sliding with all fours spinning

I the standard seats are crap for holding you in place I saw someone had an EVO7 drivers seat, matched the interior colours and looked to be the goods!

 

[VR-04-TT]

I've got Evo 5 seats, they suit perfectly. Especially if you have the carbon-look interior.

For interest's sake, I'll get the part number of the Bilsteins that my Galant came with and I'll see if I can find out what springs they have. Always good to have more info on the table to work off.