SPL Parts vs VAC lower control arms

Cytoplasm0671 · 04-25-2023, 08:06 AM

If I've lowered my car 1" via Dinan springs, should I get SPL Parts control arms for roll center correction (kern417 seems to prefer this) or is it ok to get VAC control arms with no roll center correction but which was created for stock suspension geometry?

Cytoplasm0671 · 04-26-2023, 08:47 PM

Bump

FaRKle! · 04-27-2023, 11:28 AM

In order to properly do roll center correction, ALL of the arms (tension strut, LCA, and tie rods) need to have that adjustment. It doesn't help if only one of the arms has it.

Also, if you're going to do it, you should really have a center of gravity measurement done to see how much correction is really needed.

Cytoplasm0671 · 04-27-2023, 03:28 PM

How might I get my center of gravity measurement done?

SuperLomi · 04-27-2023, 05:27 PM

Quote:

Originally Posted by Cytoplasm0671

How might I get my center of gravity measurement done?

I was curious so I looked it up.

https://www.caranddriver.com/news/a18201745/explained-how-to-measure-center-of-gravity-height/

RbBugBitMe · 04-27-2023, 11:57 PM

Quote:

Originally Posted by FaRKle!

Also, if you're going to do it, you should really have a center of gravity measurement done to see how much correction is really needed.

Measuring it is one thing and perhaps you mean measuring it before and after though that is highly predictable. I'm curious if you'll expand on why and how you use that info to determine how much RC lowering is needed and how you get there when you can not control the front strut mounting point or angle without a custom upright.

AllaVodka · 04-28-2023, 11:08 AM

As someone who litetally just had the vac monoball thrust arms removed because of NVH with dinan springs and shockware… i’d say to just leave your bushings stock unless you live in an area with absolutely perfectly paved roads.

Cytoplasm0671 · 04-28-2023, 11:51 AM

Wait, so as a guy on moderately rough paved roads, I have a choice between OEM springs and OEM control arms?

freakystyly · 04-28-2023, 01:08 PM

We rarely modify with comfort and longevity in mind. Sometimes we take things too far and need to reset.

04-25-2023, 08:06 AM	#1
Cytoplasm0671 Armchair Aristocrat 314 Rep 437 Posts Drives: 340i 6MT Join Date: Sep 2022 Location: West Michigan iTrader: (0)	SPL Parts vs VAC lower control arms If I've lowered my car 1" via Dinan springs, should I get SPL Parts control arms for roll center correction (kern417 seems to prefer this) or is it ok to get VAC control arms with no roll center correction but which was created for stock suspension geometry? Last edited by Cytoplasm0671; 04-26-2023 at 08:40 AM..
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04-26-2023, 08:47 PM	#2
Cytoplasm0671 Armchair Aristocrat 314 Rep 437 Posts Drives: 340i 6MT Join Date: Sep 2022 Location: West Michigan iTrader: (0)	Bump
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04-27-2023, 11:28 AM	#3
FaRKle! Brigadier General 4035 Rep 3,545 Posts Drives: 328d Wagon, M2 Comp, i4 eD35 Join Date: Sep 2016 Location: Bay Area, CA iTrader: (4) Garage List 2023 BMW i4 eDrive 35 [5.00] 2017 BMW 328dx Wagon [10.00] 2021 BMW M2 Competi ... [5.00]	In order to properly do roll center correction, ALL of the arms (tension strut, LCA, and tie rods) need to have that adjustment. It doesn't help if only one of the arms has it. Also, if you're going to do it, you should really have a center of gravity measurement done to see how much correction is really needed. __________________ -328d Wagon Build Log (with helpful reference links) -My YouTube Channel for some of the best DIYs and in depth information Please don't PM me for suspension recommendations unless interested in paid private consultations.
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04-27-2023, 03:28 PM	#4
Cytoplasm0671 Armchair Aristocrat 314 Rep 437 Posts Drives: 340i 6MT Join Date: Sep 2022 Location: West Michigan iTrader: (0)	How might I get my center of gravity measurement done?
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04-28-2023, 11:08 AM	#7
AllaVodka Captain 634 Rep 710 Posts Drives: BMW B58 Join Date: Dec 2020 Location: CT iTrader: (0)	As someone who litetally just had the vac monoball thrust arms removed because of NVH with dinan springs and shockware… i’d say to just leave your bushings stock unless you live in an area with absolutely perfectly paved roads.
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04-28-2023, 11:51 AM	#8
Cytoplasm0671 Armchair Aristocrat 314 Rep 437 Posts Drives: 340i 6MT Join Date: Sep 2022 Location: West Michigan iTrader: (0)	Wait, so as a guy on moderately rough paved roads, I have a choice between OEM springs and OEM control arms?
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04-28-2023, 01:08 PM	#9
freakystyly Lieutenant Colonel 3072 Rep 1,824 Posts Drives: F22 B58 6MT Join Date: May 2016 Location: Ontario iTrader: (0)	We rarely modify with comfort and longevity in mind. Sometimes we take things too far and need to reset.
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