318 springs on a 325 - The good, bad and the ugly?

[BMWdriverwanted]

Someone mentioned this for a softer ride. I am not sure that would happen as the springs would be more compressed resulting in putting the spring out of its soft spot and into a more compressed, harder rate. I would think it would negate a softer ride, but, would lower the front. Cant say I am going to do it, but, since someone suggested it, I was just curious if it had been done and the results.

[405style]

Won't even hold the weight up. If you wanna crash , go for it! Remove the stabilizers as well for extra sway

[BMWdriverwanted]

Glad to see I can always get a serious answer from the board. Maybe pull a couple of lug nutts too, lol. :rolleyes

[405style]

Ok look, If you want the supple ride of a Cadillac in a bmw, BUY A e34. It will give you exactly what you want stock with those rims you want so much without any stupid hack mods.

e36s are compact cars first and foremost, they do not even have the weight needed to "sway" and whatever else you conjured up for yourself. a e34 does.

There is your final answer. Don't believe me, then go drive any e34 for sale and you will get EXACTLY what you want to do now, just like that.

[joey79]

Glad to see I can always get a serious answer from the board. Maybe pull a couple of lug nutts too, lol. :rolleyes

This would be a good way to shed rotational mass.

[Moron95M3]

ugh time to use engineering for an explanation ;)

"Someone mentioned this for a softer ride. I am not sure that would happen as the springs would be more compressed resulting in putting the spring out of its soft spot and into a more compressed, harder rate. I would think it would negate a softer ride, but, would lower the front. Cant say I am going to do it, but, since someone suggested it, I was just curious if it had been done and the results."


Preliminary info:
318 springs are 'softer' than 325 because the car is lighter. = 318 springs have a lower overall spring rate (force/inch - how much they'll compress at a given force)
OEM springs are progressive. This means they vary in spring rate, stiffer in one spot than another. Let's look at this as if there are two springs, say one stiff one on top of one soft spring. (ease for understanding)


Assumptions:
Springs are same initial length
318 springs really are softer overall than 325 springs (I say overall because they're progressive)
Think about progressive springs as a short stiff spring on top of a short soft spring
Expectations:
the quote here "the springs would be more compressed resulting in putting the spring out of its soft spot and into a more compressed, harder rate"

this quote "but, would lower the front."

Engineering reasoning
"the springs would be more compressed resulting in putting the spring out of its soft spot and into a more compressed, harder rate"
Wrong because:
if you assume a progressive spring is two short springs with different rates, then they will both be compressing due to the load. Just because the weight (weight = force due to gravity of the mass) is more, the spring rate stays the same. you don't just compress the soft spring then start compressing the stiffer spring. Force is always transferred through a spring, so both small springs are seeing the same force. This means that if you put 100lbs on the front of a 318 and 100 lbs on the front of a 325 with the same 318 springs, they'll both compress the same amount more.

Correct when
The only time that your statement here is correct is if the softer small spring is fully compressed, acting as a solid member (coils touching). This would results in a stiffer spring, like you mentioned. However I would hope BMW designed their springs so that this would not happen, and that when/if the spring ever hits full compression, every coil is touching.


"but, would lower the front."
Correct, with assumptions
I agree, you might see some lowering occur too, however this is only assuming the 318 and 325 spring have the same initial length.


Final thoughts from me (remember I'm just some guy on the internet)

I doubt you'll be maxing out the spring, so you should still feel the benefit of the overall softer 318 spring up front. However I could imagine you may max them out more often on bumps due to the softer overall rate.
You might see some lowering, but it might not be much
I've never seen any real data on OEM springs, I've looked a lot. So what you're doing is based on a lot of assumptions - however they are assumptions that make sense...

I hope this helps/makes sense - I've thought a lot about springs and still get mixed up a bit, so I know this is confusing.

[locks325is]

The op is just running his mouth for attention, not going to do ANY of the crap he keeps post about!

[BMWdriverwanted]

ugh time to use engineering for an explanation ;)

"Someone mentioned this for a softer ride. I am not sure that would happen as the springs would be more compressed resulting in putting the spring out of its soft spot and into a more compressed, harder rate. I would think it would negate a softer ride, but, would lower the front. Cant say I am going to do it, but, since someone suggested it, I was just curious if it had been done and the results."


Preliminary info:
318 springs are 'softer' than 325 because the car is lighter. = 318 springs have a lower overall spring rate (force/inch - how much they'll compress at a given force)
OEM springs are progressive. This means they vary in spring rate, stiffer in one spot than another. Let's look at this as if there are two springs, say one stiff one on top of one soft spring. (ease for understanding)


Assumptions:
Springs are same initial length
318 springs really are softer overall than 325 springs (I say overall because they're progressive)
Think about progressive springs as a short stiff spring on top of a short soft spring
Expectations:
the quote here "the springs would be more compressed resulting in putting the spring out of its soft spot and into a more compressed, harder rate"

this quote "but, would lower the front."

Engineering reasoning
"the springs would be more compressed resulting in putting the spring out of its soft spot and into a more compressed, harder rate"
Wrong because:
if you assume a progressive spring is two short springs with different rates, then they will both be compressing due to the load. Just because the weight (weight = force due to gravity of the mass) is more, the spring rate stays the same. you don't just compress the soft spring then start compressing the stiffer spring. Force is always transferred through a spring, so both small springs are seeing the same force. This means that if you put 100lbs on the front of a 318 and 100 lbs on the front of a 325 with the same 318 springs, they'll both compress the same amount more.

Correct when
The only time that your statement here is correct is if the softer small spring is fully compressed, acting as a solid member (coils touching). This would results in a stiffer spring, like you mentioned. However I would hope BMW designed their springs so that this would not happen, and that when/if the spring ever hits full compression, every coil is touching.


"but, would lower the front."
Correct, with assumptions
I agree, you might see some lowering occur too, however this is only assuming the 318 and 325 spring have the same initial length.


Final thoughts from me (remember I'm just some guy on the internet)

I doubt you'll be maxing out the spring, so you should still feel the benefit of the overall softer 318 spring up front. However I could imagine you may max them out more often on bumps due to the softer overall rate.
You might see some lowering, but it might not be much
I've never seen any real data on OEM springs, I've looked a lot. So what you're doing is based on a lot of assumptions - however they are assumptions that make sense...

I hope this helps/makes sense - I've thought a lot about springs and still get mixed up a bit, so I know this is confusing.

Fact: I am not a spring-ologist, so, I am assuming only what I can think of in theory. I did not take a course on springs, spring rates and spring comparisons. Thanks for taking the time to point all that out, correct or not, as it is more info than i have thought about and gives me more direction to think. I am only suggesting it because I am looking at options and ideas and someone said why not use them. I have no idea if it is safe to rey and I am not gonna just run out and put my 318 springs on to try it out, but, I am sure there are, and I have seen them, engine swaps in 318 cars. I guess what I need to do is find those guys and ask them what has become of their ride too.

Thanks again for the insight. :thumbup:




The op is just running his mouth for attention, not going to do ANY of the crap he keeps post about!

Easy there skippy. I will do when I know it is safe AND it will achieve my goal. Until then, I am not touching a thing.

[MrPink]

you sound like your either A) not thinking things through, or B) shouldnt be owning an e36.

The e36 is a "sport compact executive car" its NEVER going to ride like a Cadillac. its ment to be a good handling car for those who want a bit of luxury.

[BMWdriverwanted]

An e36 is nothing more than a go-kart, same feel! There is no "luxury" in its vocabulary, sadly enough.

Wait, how am I not thinking things through? Someone ELSE said to use them, NOT me. I am just asking about them. Thats not thinking it through????

Funny how its all directed at me!? Meh, oh well......

[sunbrn]

Go out and remove the sway bars. It's free and only takes minimal time. Then report back on how it drives. Then YOU can be the one that knows what is going on and can give feedback to all of us. Nobody really does the things you are asking for.

[BMWdriverwanted]

What does a sway bar have to do with 318 springs someone else mentioned? If someone else mentioned it, shouldn't I check to see? Am I allowed to even do THAT? :confused

[Rudolph320i]

id just like to ask how the e36 has nothing luxurious about it? if you are comparing to todays cars then it is certainly more spars in terms of luxury, but for the times it was quite a comfy car that could still handle. the OBC and digital climate control that some have and the amount of power available certainly put it far above some other sport vehicles of the day.

[BMWdriverwanted]

Then do we need to differentiate even further, like luxury and creature comfort then? Some would consider it a "luxury" to have a steering wheel to drive their new car off the lot as opposed to having to bring their own.

Sorry, dont have time to think out a perfect rebuttal, in the middle of having a life and changing out fish tank water, but, you get where I am going.

[Rudolph320i]

well im just saying, having driven bmws from the 80s, and multiple other vehicles from the 90s which the car would be compared to, it was quite a nice car for its time. i cant think of many cars in the day with heated seats, or a lot of the other amenities that came with an e36.

[BMWdriverwanted]

Thats what has me a little confused. They did not make it better than it probably could have been all the way around nor did they advertise it, as far as I know, as a "this is not the comfortable line". Well, at least to those not in the know, and, even if it did, people on here are making their car ride HARDER than stock and thats okay. Not sure why people are so bent out of shape with me going in the opposite direction. Well, I now why, their brain just cant comprehend. Still, one would think this place is a place where a man can have individuality, but, oh well, all is normal in life, I digress, lol.

[Rudolph320i]

well seeing as how the e36 was designed to be one of the best handling cars in the world, and thats why most of us got into bmws and the like, it goes against the grain that one would make the car handle worse. they arent fast in a straight line, so they kind of have to be good in the turns. we do not all like the same thing because we are here, we are here because we generally enjoy similar things. there is a difference.

[joey79]

Interesting...

[BMWdriverwanted]

I think were all here because we like the body style first and foremost. Handling comes in a close second and slamming just fks it up, as far as handling goes, but, half the people here do that! So, along comes this dude and just doesnt like the ass pounding shoved rear shocks through the wheel well ritual (I will take a pick of the extra hole it punched in the car). I think I can make the car a pleasurable ride while holding on to a lot of its traits including its looks. In the meantime, I didnt think I did anything wrong asking about what someone else said. "I" sure as hell had no thoughts or intentions of 318 springs until someone said something. Just trying to find out if its fact, fiction, good or bad.

Fast in a straight line? I beg to differ a little. From 3,5k rpm and up, that 2.5 goes like a bat out of hell, and, coming off a LS1, I am surprised. Just have to also find that pull down low, wherever it went?

[julianashull]

The op is just running his mouth for attention

[Rudolph320i]

there isnt any pull down low. and, personally, i dont care who suggested what. im here because i love bmws for what they are, good performance cars that handle well and at least the old ones are in my price range. the only way i actually got into them is because of a friends cheap e30 for sale and the need for a car. you are technically trying to make the car do something it was never thought it would have to do, hence the lack of aftermarket parts to make it do as you want it to. im not here to talk about who said what or what anyone things about that, im just saying that its gonna be tough, but as someone else said the airbags are probably your best bet at softening the ride.

[WTFGERMAN]

Lol I love when I troll a thread and it becomes another random bullshit thread.

[BMWdriverwanted]

Never a straight answer around here, just romper room antics! I guess thats what you get from $3k car owners. The adults would be the ones with the $30k cars? Though, I would never pay $30k for one of these, so, thats my excuse for being here, lol. :shifty

[WTFGERMAN]

Truth is you're never going to make a 3 series ride like a caddi, they are just not designed that way and if you think a stock setup is too harsh you're better off in a caddilac as well but I do realize you want a BMW not a caddilac for visual appeal. Recommendation; get a 7 series and be done with it. 3 series are solely made as a sport compact and it's designs are there to accompany german roads which are much smother than anything in the US. It's definitely a different thought trying to make a BMW drive and handle like a caddilac but it's also impossible.

3k car owners huh well if you keep asking these idiotic questions on how to make a sports car ride like a piece of shit you're not going to get a straight answer. Aside from that we all may have started with a 3k car but we know what Bmw's are designed for, and then spent money accordingly.

[BMWdriverwanted]

Yeeeeeup, thats exactly how I want "to make a sports car ride like a piece of shit". A big steaming pile of shit. Not a small one like a pile of horse shit, but a big one, like a huge steaming pile of elephant shit after a giant tainted bag of peanuts. :buttrock