Koni Sport and 135i Springs - Again

[Tommm]

I have an 08 128i with 47k on the clock. I have a set of low mileage springs from a 135i and a set of Koni yellows in the garage.

I often commute 100 miles a day, I bought the car a year ago at 32k with a set of new bridgestone run flats, I have new 16" normal winter tires, and I also have 245/40/17 R compounds for a half dozen track days.

I know about the rear subframe bushings. This is my DD, and she who must be obeyed has a bad back so that may not happen

The question is half or three quarters firm? Any other non stock parts suggestions? I am going to order Lemforder front mounts since I drive too much to adjust camber.

[ianc]

Get rid of those stock springs and put something stiffer like Eibachs in there. It's too much labour to change the struts/shocks without doing the springs while you have the chance. You will not be happy with the stock springs when you lose the run flats (even with them)...

ianc

[John_01]

I'd expect the 135i springs to be about 7% stiffer what comes with the 128i M-sport (133lb/in vs 124lb/in).
It will probably just make the front ride height about 10mm higher than it would be with 128i M-sport springs.
I understand you don't want to make the car too low so its going to ride badly, but I'm just not sure the 135i springs are the best solution.

[asbrr]

+1 don't do stock springs (135i or other). If anything do BMW performance springs, they are stiffer yes but only about 10mm lower.

Changing away from runflats will give you ride quality improvement. For the rear subframe bushings, maybe just do inserts which will not have any kind of NVH penalty (the full bushings don't really make a huge negative impact on NVH IMO, but you're trying to keep things comfortable).

Question though: Why bother changing anything if the wife cannot handle a stiffer ride? Is she ok with the M-sport suspension as is?

[Tommm]

My car is a 128. I have 135 springs. I have other cars, so the 1 is my main car. She cant take too stiff a ride, plus i commute on crappy roads. Hence the slightly lower 135 springs. I will be the one doing the labor. I plan on buying alll new parts so that the swap is almost plug and play.

I have to do things in steps, getting her back to approve each step. The fourth generation Z28 with bigger C5 rims and the Doug Rippie Bilsteins was not a good move.

I will probably do rear subframe next year. I want it a bit more responsive, not full on yet.

Hope that makrs sense. I have/had yellows in my different 944s.

If i use the 135 springs would 2/3-3/4 on the yellows be too stiff for the springs?

[lowbudgethero]

get the e92 dinan springs

If i use the 135 springs would 2/3-3/4 on the yellows be too stiff for the springs?

probably not, i prefer a fast reacting shock on softer springs than a slower reacting shock on stiff springs, ymmv

[Tommm]

Originally Posted by lowbudgethero

get the e92 dinan springs

If i use the 135 springs would 2/3-3/4 on the yellows be too stiff for the springs?

probably not, i prefer a fast reacting shock on softer springs than a slower reacting shock on stiff springs, ymmv

I'll give it a shot. Thanks.

My lap time will suck no matter what when i drive with the GT4 group.

[asbrr]

Originally Posted by Tommm

My car is a 128. I have 135 springs. I have other cars, so the 1 is my main car. She cant take too stiff a ride, plus i commute on crappy roads. Hence the slightly lower 135 springs. I will be the one doing the labor. I plan on buying alll new parts so that the swap is almost plug and play.

I have to do things in steps, getting her back to approve each step. The fourth generation Z28 with bigger C5 rims and the Doug Rippie Bilsteins was not a good move.

I will probably do rear subframe next year. I want it a bit more responsive, not full on yet.

Hope that makrs sense. I have/had yellows in my different 944s.

If i use the 135 springs would 2/3-3/4 on the yellows be too stiff for the springs?

Oh for some reason I thought you had the Msport suspension on the 128i already, which means it would almost be the same as 135i springs. But if you have the non-sport 128i, then the 135i springs will be an improvement and slightly lower than what you have.

As for the Koni comment, can't add much as I run Bilsteins myself and wouldn't know the adjustment range on the Konis.

[Tommm]

Originally Posted by asbrr

Oh for some reason I thought you had the Msport suspension on the 128i already, which means it would almost be the same as 135i springs. But if you have the non-sport 128i, then the 135i springs will be an improvement and slightly lower than what you have.

As for the Koni comment, can't add much as I run Bilsteins myself and wouldn't know the adjustment range on the Konis.

The one inch drop to stock 135 height should do it for now. I will probably do other suspension upgrades and let miles accumulate. Then when it is just an old car, turn it into a DE toy.

[John_01]

I doubt you will get a significant lowering by M-sport 135i springs, compared to comfort 128i springs. I expect the front to drop around 5~7mm. The rear may drop a bit more than the front. If you changed to 128i M-sport springs you would probably get 15mm drop all round. Changing to Performance springs would give a 25mm drop.

135i springs are the same length as 128i M-sport springs. The only difference is they are made from thicker wire, so they can carry more weight.

[Tommm]

Originally Posted by John_01

I doubt you will get a significant lowering by M-sport 135i springs, compared to comfort 128i springs. I expect the front to drop around 5~7mm. The rear may drop a bit more than the front. If you changed to 128i M-sport springs you would probably get 15mm drop all round. Changing to Performance springs would give a 25mm drop.

135i springs are the same length as 128i M-sport springs. The only difference is they are made from thicker wire, so they can carry more weight.

I may be wrong, but i remember reading a comparison of the ones when they came out, and the article said the 135 came standard with the sport suspension that's an inch lower than the standard.

That should be a 25mm drop. If im wrong, which i probably am and am mixing it up with my M roadster v Z3, i may have to rethink this. Thanks

[John_01]

Originally Posted by Tommm

I may be wrong, but i remember reading a comparison of the ones when they came out, and the article said the 135 came standard with the sport suspension that's an inch lower than the standard.

That should be a 25mm drop. If im wrong, which i probably am and am mixing it up with my M roadster v Z3, i may have to rethink this. Thanks

Its possible USA delivered cars may be different to the models we have in Australia. That's all I can think of to explain it.

[tracer bullet]

Originally Posted by Tommm

I know about the rear subframe bushings. This is my DD, and she who must be obeyed has a bad back so that may not happen.

No one would ever feel this swap with their bad back. The only time you will notice is going around a corner when you lose the rubber band feeling the back of the car gives you. Hell in fact you could argue that not having that effect is actually better for her back. Either way she will never ever notice it. It's a small fraction of the overall suspension when you are talking about how smooth or rough a ride is. Much much smaller than any spring or strut replacement is going to cause.

[Tommm]

Originally Posted by asbrr

Oh for some reason I thought you had the Msport suspension on the 128i already, which means it would almost be the same as 135i springs. But if you have the non-sport 128i, then the 135i springs will be an improvement and slightly lower than what you have.

As for the Koni comment, can't add much as I run Bilsteins myself and wouldn't know the adjustment range on the Konis.

Originally Posted by John_01

I doubt you will get a significant lowering by M-sport 135i springs, compared to comfort 128i springs. I expect the front to drop around 5~7mm. The rear may drop a bit more than the front. If you changed to 128i M-sport springs you would probably get 15mm drop all round. Changing to Performance springs would give a 25mm drop.

135i springs are the same length as 128i M-sport springs. The only difference is they are made from thicker wire, so they can carry more weight.

I haven't been able to find a definite answer. You are probably right, the drop will be negligible.

Originally Posted by tracer bullet

No one would ever feel this swap with their bad back. The only time you will notice is going around a corner when you lose the rubber band feeling the back of the car gives you. Hell in fact you could argue that not having that effect is actually better for her back. Either way she will never ever notice it. It's a small fraction of the overall suspension when you are talking about how smooth or rough a ride is. Much much smaller than any spring or strut replacement is going to cause.

No argument. I read a little more and agree.

[andrey_gta]

I do not really recommend front 135i springs, they jack up the 128i front over stock 128i Msport springs by 12mm - and I even have SP perches that reduce 10mm height. The car will have somewhat of a 3 series look, with good gap in the rear and more gap in the front. Otherwise the comfort & performance is good on fresh shock/sturts.

Look towards eibach, BMW perfromance, or even HR OE touring. Dinan & Swift seem to offer a sensible height comparable to BMW perf.

Careful of 3 series e92 spec sprigs too, as the rear will have a different drop, while the front's extra height maybe what you are looking for.

[Tommm]

Originally Posted by andrey_gta

I do not really recommend front 135i springs, they jack up the 128i front over stock 128i Msport springs by 12mm - and I even have SP perches that reduce 10mm height. The car will have somewhat of a 3 series look, with good gap in the rear and more gap in the front. Otherwise the comfort & performance is good on fresh shock/sturts.

Look towards eibach, BMW perfromance, or even HR OE touring. Dinan & Swift seem to offer a sensible height comparable to BMW perf.

Careful of 3 series e92 spec sprigs too, as the rear will have a different drop, while the front's extra height maybe what you are looking for.

Can someone lay out the differences between the three springs
128i stock - Whats in my car now (the only options my car left the old Skoda plant with was butt warmers and silver paint)
135i stock - Whats in a box in my garage
128i Sport - I thought this was the same as 135i stock
M Sport - Are these the yellow ones?

What is the difference between each?

[asbrr]

Originally Posted by Tommm

Can someone lay out the differences between the three springs
128i stock - Whats in my car now (the only options my car left the old Skoda plant with was butt warmers and silver paint)
135i stock - Whats in a box in my garage
128i Sport - I thought this was the same as 135i stock
M Sport - Are these the yellow ones?

What is the difference between each?

128i Stock - these are the "non-sport" or "non-M-Sport" springs. Soft and higher ride height.

135i Stock - In North America at least, ALL 135i cars came from the factory with the M-sport/Sport springs. M-sport and sport are the same thing in terms of suspension. A 135i will always sit lower than a 128i NON-SPORT.

128i Sport - these are stiffer and lower than the 128i stock/comfort springs. These also came in "M-sport" equipped 128i cars. M-sport is a package that gives you bodywork, suspension, and interior/trim upgrades. The suspension is basically the "sport" suspension and is sometimes called the "m-sport" suspension

M-Sport - this is the same as the sport suspension

BMW Performance - these are the yellow springs you get from BMW. They are about 10mm lower than Sport/M-sport springs, and about 30% stiffer.

Last note - if you put 135i springs on a non-sport 128i, it will not quite be as low (especially in the front) because the 135i Sport/M-Sport springs are a bit stiffer than the 128i Sport/M-Sport springs.

Clear as mud?

[gjm120]

A little nuance to what asbrr stated, the amount of drop by putting 135i springs on a non-sport 128i will depend on what how the 135i was optioned and how your car is optioned. Extreme case is if you put springs from a 135i AT conv on a MT 128i with no sunroof.

I put a lightly used 135i suspension that was for or an AT 135i and got very little drop (which suited me fine). Also, got a much better handling firmer ride, but, I can't tell how much of that was due to springs, the new dampers, the M3 front control arms or the new mounting hardware that I did at the same time.

If you don't know the car your 135i springs came off of, you need to look at the labeling then do a little digging.

[Tommm]

Thanks guys. Thats what i was looking to confirm. I can ask the seller what his car had/has but it probably wont matter much. Right now I am more interested in the macro. You confirmed I will get a slight drop which is all i want, and firmer springs to go with my Koni sports. That should keep me happy for a while.

[Tommm]

You know i just BS'd myself and you. As soon as i get home i will probably go to the box with the springs and look for markings. I probably wont sleep until i know the tiny useless details.

[gjm120]

Originally Posted by Tommm

You know i just BS'd myself and you. As soon as i get home i will probably go to the box with the springs and look for markings. I probably wont sleep until i know the tiny useless details.

Can't hurt to post what you find out. Me or someone else on here might be able to tell you something.

[John_01]

135i M-sport springs normally have codes "D6" front, "L3" rear.