[Wires]

Not sure why coil overs won't help him. As soon as you lay down the power, the car will tend to twist with the right wheel squatting which reduces grip on the left wheel causing it to spin. Not saying this is the end all - be all solution, but there is still huge benefit with coil overs.

Just doing the Dinan shockware upgrade on my xdrive made a difference on grip. Not LSD awesome, but in many cases where I had wheel slip from chassis rotation were now gone.

[Skyhigh]

Originally Posted by Wires

Not sure why coil overs won't help him. As soon as you lay down the power, the car will tend to twist with the right wheel squatting which reduces grip on the left wheel causing it to spin. Not saying this is the end all - be all solution, but there is still huge benefit with coil overs.

There is zero benefit of coil-overs with respect to traction.
The twisting is so negligible that it makes 0 difference. Stock suspension of a nearly 2 ton vehicle is not made of cheese either.

If your theory was right, the comfort-focused SUVs would have the most terrible traction ever.... and we all know that is not the case. Traction does NOT depend on suspension. Only handling and aerodynamics and of course comfort.

[sygazelle]

Originally Posted by BimR

Does no one put rocks in their trunk anymore? 😉

Bags of sand work too!

[sygazelle]

Originally Posted by F32Maniac

Hello all,

I own a 2017 f32 440i RWD, stage 2 (BM3). As you can imagine, I struggle with traction even from rolling (60km/h). The solutions im aware of include coilovers, wider/better tyres, and LSD.

I need my grip sorted before I upgrade the turbo, but dont want to spend on all of the above. If you were to rank which would contribute more to grip, which one would it be? I am leaning towards lowering the car via coilovers. Going for Trofeo R's is not an option, tread life is not a sacrifice im willing to do pre-turbo install

FYI: I am on michelin 4S Pilot sport 255/35 and 225 tyres.

Please share your grippy setups!
Thanks

I have no grip problems at all. My setup is completely stock on 18" all weather high performance tires (square setup) and DHP with adaptive suspension. Oh, that's right. I forgot to mention I have the lowly 328 with a 4-banger N20 engine. No grip trickery required!

Seriously, good luck finding the right balance to get the grip you need. I'm properly jealous of all your torque and horsepower.

[Wires]

Originally Posted by Skyhigh

There is zero benefit of coil-overs with respect to traction.
The twisting is so negligible that it makes 0 difference. Stock suspension of a nearly 2 ton vehicle is not made of cheese either.

If your theory was right, the comfort-focused SUVs would have the most terrible traction ever.... and we all know that is not the case. Traction does NOT depend on suspension. Only handling and aerodynamics and of course comfort.

I'm going to call BS to that it doesn't matter at all. When Ford switched the Cobra from live axle to independent suspension, they suffered a ton of wheel hop/traction issues.

Not sure if I'd compare a 5 ton / 200HP SUV to a much lighter 450HP car with this comparison, since there is a ton of other physics elements at bay.

[Skyhigh]

Originally Posted by Wires

I'm going to call BS to that it doesn't matter at all. When Ford switched the Cobra from live axle to independent suspension, they suffered a ton of wheel hop/traction issues.

Not sure if I'd compare a 5 ton / 200HP SUV to a much lighter 450HP car with this comparison, since there is a ton of other physics elements at bay.

If you call BS, you need to prove it. I am happy to install the sloppiest suspension you can find compatible with an F3x and can guarantee you I will still do under 5s. 0-100!

Comparing different types of suspension, as in your example, to simply a change in height of the same suspension is BS to start with.

But hey, if placebo made you think your traction was improved by lowering the car - it still counts as a success! So don't regret it.

[MacklinUSOB]

Originally Posted by Skyhigh

If you call BS, you need to prove it. I am happy to install the sloppiest suspension you can find compatible with an F3x and can guarantee you I will still do under 5s. 0-100!

Comparing different types of suspension, as in your example, to simply a change in height of the same suspension is BS to start with.

But hey, if placebo made you think your traction was improved by lowering the car - it still counts as a success! So don't regret it.

You called bullshit first, let's not play that game here. It's on you to prove that negative.

Coilover kits almost always increase spring rates, which have a very large impact on traction, as does the ability to corner balance.

[Wires]

Originally Posted by Wires

I'm going to call BS to that it doesn't matter at all. When Ford switched the Cobra from live axle to independent suspension, they suffered a ton of wheel hop/traction issues.

Not sure if I'd compare a 5 ton / 200HP SUV to a much lighter 450HP car with this comparison, since there is a ton of other physics elements at bay.

Aftermarket coil-overs doesn't mean you are changing ride height. Stiff springs give better traction, period.

That being said, stiffer rear sway bars will also help by keeping both wheels planted.

[HighlandPete]

Originally Posted by Wires

Aftermarket coil-overs doesn't mean you are changing ride height. Stiff springs give better traction, period.

That being said, stiffer rear sway bars will also help by keeping both wheels planted.

You can lose grip with stiffer spring rates. It has been one of my gripes with some BMW models, the spring rate is too high.

Here's an interesting read.

https://www.roadandtrack.com/car-cul...ave-less-grip/

[MacklinUSOB]

Originally Posted by HighlandPete

You can lose grip with stiffer spring rates. It has been one of my gripes with some BMW models, the spring rate is too high.

Here's an interesting read.

https://www.roadandtrack.com/car-cul...ave-less-grip/

The bottom line here is absolute statements when it comes to suspension are not accurate. It affects almost every performance metric. That article comports with the premise that spring rates affect traction which is precisely the point of argument.

If there is one BMW that is far from stiff it's the F2/3X xDrive. At the same time I absolutely agree with your opinion that some BMWs are unreasonably stiff, the Competition models being the worst offenders.

[Wires]

Originally Posted by MacklinUSOB

The bottom line here is absolute statements when it comes to suspension are not accurate. It affects almost every performance metric. That article comports with the premise that spring rates affect traction which is precisely the point of argument.

If there is one BMW that is far from stiff it's the F2/3X xDrive.

Are you talking about my loose and sloppy car?

Yeh, I need springs, just don't want to commit to them. My 340 is FAR from tight in the suspension area. Body rolls, it floats, far from "the ultimate driving machine". Dinan Shockware helped a lot, but that's a bandaid for sloppy springs.

[MacklinUSOB]

Originally Posted by Wires

Are you talking about my loose and sloppy car?

Yeh, I need springs, just don't want to commit to them. My 340 is FAR from tight in the suspension area. Body rolls, it floats, far from "the ultimate driving machine". Dinan Shockware helped a lot, but that's a bandaid for sloppy springs.

Hey now, I won't do that to any of the xDrive folks. The RWD is mildly more composed in stock form, sure. The realistic take is that the majority of F30's are getting up there in mileage, once the stock dampers have 50k on them there is little to no difference.

To circle back to OP's original question for his RWD car, a diff is going to "rank first" considering you already have great street tires. It's also going to be the most expensive, but this game has always been pay to play, especially as you start down the path building a beast motor. Enjoy.

[jmg]

The MPS4S has excellent grip to wear characteristics, but if you are going big turbo then I would start with stickier tires. Sorry, wear is a trade off, you can't avoid it.

Another question is what you want to accomplish with these mods. Drag? Track? Or just highway pulls. Do you just want to be fast or do you want a balanced well handling car?

If you just want to be fast on the street and on the highway then RE71R, Goodyear Supercar 3 or MPS4S in order of grip from greatest to least. You also might look into Falken RT660, Hankook RS4's, or Yoko AO52. Personally I love the RE71R's for track and street use. They are expensive and hard to find now however.

Yes, I would get tires before anything else if you are really about true performance.

[Londoner]

The MP LSD on my RWD 340i has made for dramatic improvement in handling and traction. The easiest way to describe is it has changed the car from a one wheel drive to two.

In my humble opinion any increase in power is almost pointless until you install a LSD.

You will not regret.

[Silverlining_m2]

Raise the boost reduction in 1st gear to 20%, and 10% in 2nd. If that doesn't work, reduce it a little more.

Enjoy being faster.

[Logicoeur]

Everyone is arguing about grip, but not specifying that dependent on the situation grip is solved differently. OP is not tracking so he is looking for straight line and from-a-dig grip. That is why suspension will not solve anything for him.

Once you move away from straight lines and want to improve grip on turns and such you need to focus on keeping the tires on the ground. That's when suspension comes in; coilovers, sway bars and the like. An LSD also helps here.

For straight line grip you need to focus on wheel spin and that is dictated by the tire compound, contact patch size, and slip differential between the powered wheels. If this was a racing domain than you would also add downforce here .
Focus people.

[MacklinUSOB]

Originally Posted by jmg

The MPS4S has excellent grip to wear characteristics, but if you are going big turbo then I would start with stickier tires. Sorry, wear is a trade off, you can't avoid it.

Another question is what you want to accomplish with these mods. Drag? Track? Or just highway pulls. Do you just want to be fast or do you want a balanced well handling car?

If you just want to be fast on the street and on the highway then RE71R, Goodyear Supercar 3 or MPS4S in order of grip from greatest to least. You also might look into Falken RT660, Hankook RS4's, or Yoko AO52. Personally I love the RE71R's for track and street use. They are expensive and hard to find now however.

Yes, I would get tires before anything else if you are really about true performance.

RE71R has been on top of the stack for a long time but has been discontinued since the RE71RS started rolling out in Feb of this year. Yet to see any availability in North America on those. The RT660 has edged out the old RE in some tests, but those are also tough to track down. I was looking to try those out this season but ended up getting another set of RS4 so I wouldn't be SOL should I have a failure.

OP if you're going to make the step to 200TW this year put in your order soon. A lot of the manufacturers do not produce them year-round so just keep that in mind.

[jmg]

Originally Posted by Logicoeur

Everyone is arguing about grip, but not specifying that dependent on the situation grip is solved differently. OP is not tracking so he is looking for straight line and from-a-dig grip. That is why suspension will not solve anything for him.

Once you move away from straight lines and want to improve grip on turns and such you need to focus on keeping the tires on the ground. That's when suspension comes in; coilovers, sway bars and the like. An LSD also helps here.

For straight line grip you need to focus on wheel spin and that is dictated by the tire compound, contact patch size, and slip differential between the powered wheels. If this was a racing domain than you would also add downforce here .
Focus people.

In other words… it doesn't matter either way, tires are the best way to get grip since even in cornering, what's the point of all those suspension mods if they are running all seasons (unless you want to drift).

So… tires first.

[AllaVodka]

Originally Posted by MacklinUSOB

You called bullshit first, let's not play that game here. It's on you to prove that negative.

Coilover kits almost always increase spring rates, which have a very large impact on traction, as does the ability to corner balance.

Can u guys just kiss on your front lips and make up. Lets diffuser the situation. I'm shocked by this behavior, and it needs to be shifted. Spring back to friendship. Hopefully I was able to sway your minds, cause frankly its exhausting

[alohasurftoad]

definitely LSD for drag as well as turns

get a 2nd pair of OEM rear wheels with yokohama advan A052 255/35/19. swap when necessary, for (drag)racing.

[MacklinUSOB]

Originally Posted by AllaVodka

Can u guys just kiss on your front lips and make up. Lets diffuser the situation. I'm shocked by this behavior, and it needs to be shifted. Spring back to friendship. Hopefully I was able to sway your minds, cause frankly its exhausting

If anyone wants insight to where that tone may have come from, this is a response I caught before the mods removed it. Mockery tends to fuel arguments, which I'm sure this user is aware of.

[Skyhigh]

I meant no sarcasm in either sentence. 🤷🏻*♂️