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The ones I had were 10inch 170LB, Marlin reccomended I went with 10 inch 225LB on the front, I believe others have used that weight as well, I think the rears are 10 inch 400LB, I have kept them.
Comparing fronts with 170 springs, lloked the same. Upgraded fronts to the same as stevs, 225. Make a hell of a difference to the car.
Rears not sure what they are. But noticably chunky compared to the supplied k series and the front ones. Maybe due to the extra weight of the T series. I have not changed mine at the rears.
Looks like I need to email Marlin to confirm what they think I was supplied with.
I think my rear could benefit from a slight upping, maybe 20% stiffer, and the fronts more.
We've had some wonderfully dry and crisp weather down here over the past few days, and I've been trying to get a feel for the handling of the car. It doesn't appear to lack mechanical grip, but the roll is a smidge off putting, as is the pitching when braking and accelerating.
As an aside, I'm glad I've got the larger fuel tank, as although range is acceptable when driving sensibly, when pressing on the fuel dissapears amusingly quickly.
I spoke to Mark, and he suspects I have 300 lb x 9" on the rear, and around 200 on the front. Apparently they are presently running 300 front and rear on the demonstrator (with no preload on the front), so suggested I try that, and see how I get on.
P'ah it's all fun experimentation, so I'll give it a go.
When I spoke to GAZ shocks they did have concerns about putting to heavier springs on the front, not sure how hight to go, but 300 maybe getting close. Maybe a chat with GAZ may be of some benifit.
I spoke to dampertech, who are the distributor that supplies Marlin. They didn't see a problem with 300lb.
Mark said 300lb is the upper limit.
At the end of the day, I'm quite happy playing around, and will report my findings - springs are £40 a pair from dampertech, so quite reasonable.
For reference, my car is about 740kg fully wet (it was 750kg at SVA, but had tools, water, spare break fluid, and other odds and end in the cabin too), and about 320 / 420 split.
What a revelation! 300lb springs on the front, and the car is massively better! The front doesn't pitch and dive like it did previously, and the car feels generally more planted.
The only thing that I need to get are some helper springs, to get the ride height correct - at the moment with zero pre-load, the front is sitting a little too high.
Now all I need is the new rear end from Marlin, some annual leave, and it's track time!
John, when you say zero preload do you mean that the spring is not compressed at all ie with the c-spanner adjuster? Why can't you simply wind down the spring?
At the moment, the adjustment collar is wound down to just touch the spring when fully extended, and like this the front is about 10mm too high. If I wind the spring back (to lower the ride height), then the spring will unseat when the suspension fully extends (say over a hump back bridge), which is not good.
I've ordered some faulkner 4" helper springs now, so problem solved.
I really can't believe the difference - the car feels sooooo much better to drive.
Yes I have the larger fuel tank. That said, full of fuel, or empty, the front felt stupidly soft with my original springs - it pitched and dived in a way quite inappropriate for the car's purpose (something to drive, when you're in the mood... a bit like a motorbike might be).
My daily driver pitches and rolls far less than the 5EXI did with the soft front springs.
John,
As you can imagine I'm reading all this with interest. Like you I have 250s on the front and 300s on the rear as per Marlin's supply. My experience with playing round with suspension etc is almost nill so knowing where to start was tricky... I may well be following your lead here I think, particularly as you say it's what Marlin are running now too. How harsh does it make the ride?
Unfortunately my tinkering time is going to be limited as march is bad for me at work and then I'm jacking it all in and going travelling for an extended period. Shame I'm not going to get this summer to play in my new toy but I guess it will still be there when I get back! I think the new rear end will have to wait until then.
Richard
I'm pretty sure my fronts were 170 lb, although all I have is gloomy memories of what I read when I first fitted the springs, as the markings have rubbed off.
Ride comfort is absolutely fine with the stiffer springs, but the car feels far more secure, and generally more pleasant to drive - hard to encapsulate the feel, but I find it much better. It's not placebo, that much I'm sure.
The only experience I have of playing with suspension dates back to racing RC cars as a nipper..... but the effects of changes must be largely transferable.
On the basis that the handling is key to the car's enjoyment, I've ordered a few books to read. I don't imagine I'll turn into a vault of knowledge overnight from reading about suspension design, but it should help me make some relatively informed decisions.
Ultimately the ability to tinker is why I went for a kit car, rather than the cheaper option of a vx220 turbo.
For reference, I bought the springs from Dampertech, who I understand supply marlin with the dampers (but not the springs).
Travelling sounds like a good plan, before age and responsibilites really kick in!
John, what length springs did you opt for and whats the benefit of fitting the helper spring over say a longer main spring and simply winding it down slightly?
To get the car to sit at about 150mm you need to compress the damper rod about 50% of the way in (for arguments sake). If you set the spring to zero pre-load, with the damper rod fully extended, and the coil adjustable collar just touching the spring, with a 300lb spring there isn't enough weight in the car to compress the spring to achieve the ride height.
If you back off the adjustment collar, then when the front suspension is unloaded the spring will rattle freely on the shock, and it's not impossible for the bottom coil seat to fall off. The helper spring allows the adjustable coil seat to be wound out to acheive the desired ride height, but because the helper spring is 4" long and rated at 4lb it will extend once the main srping has run out of length, and maintain a little bit of pressure on the spring / coil seats, and keep thing in place.
I've got 9" front springs.
edit: having cleaned up my Marlin supplied front springs, I've discovered they are 170 lb 10".
Picking up again about springs, I wanted to know what I got!
One spring reads ‘10 300’ so that’s easy (rear = 10inch 300lb rating).
The front ones are unmarked and a lot less stiff.
I can use the calculation to see how close my measuring can get with the formula and the 10 300 then use the same measuring techniques to estimate the front ones.
Then I can choose what I need. That will come later from a bag of bits in the back of the garage or from a spring supplier.
This formula helps to work out what you got, the web site does it better if you are not into the math’s and calculators.
This assists you to work out approx. what you have in your hand, steady boys… If you are offered a set of springs and are unsure of its rating or if drop them all on the floor and mix them all up…
By the way the coil measurement is the dimension under the paint…. It does not include the paint thickness in its calculation.
FORMULA:
spring rate =
modulus of spring steel X wire diameter4
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8 X number of active coils X mean coil diameter3
(modulus of spring steel = 11,250,000 pounds/inch2 = 78,500 newtons/millimeter2)
