I30T 2000

Folks on here probably know that the Infiniti I30 is just a slightly bigger and heavier Maxima.

I have a 2000 Infiniti I30t. The "t" model is sportier than the base model, with stiffer suspension, among other things.

Unfortunately, the "t" ride is quite harsh, particularly in the rear. I would like to fix the rear harshness by swapping in some softer Maxima springs, while also replacing the OEM struts. (Springs and struts are interchangeable between the Maxima and Infiniti I30.)

I know that Maximas of that era had one set of rear springs for the base and luxury models, with a different set for the SE model.

I have a set of rear springs from a Maxima SE sitting in the garage. I do not want to put them on unless they are actually softer than the stiff I30t springs. The two sets of springs look identical to each other, but eyeballing may not reveal a difference.
I suspect that Nissan used the same stiffer springs on the Maxima SE and Infiniti I30t. Can anyone confirm or deny this?

Or, alternatively, please tell me how to determine if the 2000 Maxima SE springs sitting in my garage are softer then the 2000 I30t springs that came with the car.

Thanks in advance!

4th gen maxi

iTrader: (1)

There is a formula that can get you a lb per square inch rate within 10lbs if done right.
If your willing to do a lil math it is actually a very accurate way of doing it all you need a dial caliper and calculator.

Rate= wire diameter to the fourth power *type of steel / 8*number of free coils+.5* inside diameter of coil plus the wire diameter to the third.

Lol I know it sounds crazy whole lot of work just for the compression rate but I know It will come handy to some one later on as it does in the high performance field.

Here's an example off eibachs drag springs we tested.

Wire dia. = .41" to the forth = .02825"
Type of steel= spring steel = 12,000,000
When you multiply these two you get=339,000
Second part of formula goes 8*(6)+.5 number of coils that are not cut only.=48.5
We measured inside diameter of coil to 4.21" add .41" wire dia. Cube it and you get= 98.6" multiply these two (48.5*98.6)=4782
Last part 339,000/4782= 70.9

Reason why I bring this up is because manufacturers are not always on point. As these were rated at 75lb per inch when we tested them and yield 73.4lb which is pretty damn gooooood from my desk. !

Chris Gregg

iTrader: (59)

I think that's great feedback. My question would be though, at what point of difference is the spring rate relevant? I mean, is there a relevant - noticeable - difference between say 75 and 70?

I believe if a person want to get specific about the outcome of their mods and preferences, doing this calculation is imperative.

Otherwise, a simpler option may be to call a Nissan and an Infiniti dealer and see if the part numbers are the same. Actually, you might even be able to do that via google. My guess though, the base model springs are the same between cars, as with the T and SE springs.

Just curious though, OP - you mention the I30 is heavier than the Maxima, based on what? Curious because that is news to me.

4th gen maxi

iTrader: (1)

That's were I'm getting to the heavier his i30 is, the softer it will feel with a spring with 70lbs per " than one with 75lbs thats at each wheel.! static weight. Not moving..Not that he needs a 75lb springs by anymeans.
Is it stock height ?