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The Suspension Mod Thread

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On 06/03/2016 at 10:29 AM, Tom B said:

I'm quite happy ATM with how my car handles, it's my daily driver and I can't see me 'Tracking' it   Just yet. My initial plan was to use Eibach lowering springs (25mm drop) and Eibach spacers to space them out (20mm front, 25mm rear) to improve stance, is this setup likely to make my car handle worse? I'm not too concerned about harshness, just don't want any less grippy-ness! Or am I better not going for springs and getting a cheaper set of coilovers? Tein Street advance, MeisterR Zeta-R's or BC Racing BR coilovers would be the sort of price range of be looking at. Any suggestions/advice?

p.s hope I'm okay asking this here!

Tein Street Advance work well, I had a good experience with them. Springs are on the softer side for a coilover (5/5 I believe), and you still get height adjustment and some degree of damping adjustment. There have been some worrying stories about early development MeisterR's, but I'm sure they're much better than they were, and BC I have no experience of.

Mark at Abbey tried the Street Advance's on my car and was impressed with how comfortable they were even on a fairly stiff setting, and at the price, they're still going to be a significant upgrade over stock. There's no need to spend close to £1000 on coilovers for solely road use (contrary to popular belief).

As @Deacon mentioned, you're probably best off going straight to coilovers. I was determined to stick with springs, but thanks to a rather unfortunate incident during fitting, was almost forced into coilovers after only 2 days on springs, and the difference was immediately noticeable. Even the low end Teins, like the Street Advance, are better damped than stock, so you get to enjoy a decent upgrade in handling and no significant change in comfort, if not slightly better (in most opinions anyway).

Of course, if you do go on track, or hit potholes at 140mph, the "experts" will tell you how useless they are, and how you should have spent more money, but in the real world, they'll be great :D 

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19 hours ago, Tom B said:

I'd like some of that too daidaiiro for as little ££ as possible. Hah. But as we all know too well in this thread.. You can't have your cake and eat it. 

My recommendation would be the RCE yellow springs.

http://www.racecompengineering.com/index.php/toyota-scion/gt86-fr-s/suspension/racecomp-engineering-brz-scion-frs-yellow-performance-lowering-springs-aka-yellows.html

They include shorter bump stops and a decent increase in spring rate which is required with a short bump travel. 

These are tuned to be 65% critical damped in the low speed region which is a nice compromise between sport and comfort without being too walloy.

They are very well regarded

http://www.ft86club.com/forums/showthread.php?t=16102

Eightysix on the other forum also has a set and really likes them. He's also a chassis engineer so knows a thing or two about suspension setup.

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Thanks to @Deacon for measuring the stock ARBs so I could finish of my suspension calculation spreadsheet. In a past life I used to design suspension for a living so its been good to refresh my memory on how it all works and generate a tool that hopefully others will find useful. You can download a copy here:

https://dl.dropboxusercontent.com/u/87478421/GT86%20and%20BRZ%20Spring%20and%20ARB%20Rate%20Comparison.xlsx

My main reason for doing this was to decide what replacement springs to order for my HKS dampers that will complement either the stock ARBs or stiffer Whiteline ARBs. My car is a Daily Driver with occasional track use and I drive over some pretty hideous roads on my way to work each day so I was concerned that a 6kg/6kg spring setup would be too much, I also had to consider that HKS only recommend a +/-2kg rate change without re-valving the dampers.

I've gone for 4.8kg F and 5.3kg rear in the end, which should have slightly more oversteer than my stock BRZ with the standard ARBs with consideration of the improved camber control at the front as well (the rear is pretty good already as its multi-link, but McPherson struts aren't great, especially when lowered a lot)  and whatever I choose it to be depending on the setting of the adjustable ARBs. 

There's most of the popular spring combos on there and you can enter data for any aftermarket bars if you've got the rate, %change or just the bar dimensions. Most people neglect to consider the proportional share of the springs and ARB's when it comes to thinking about the change in handling. Looking at the sheet you can see that a 6/6 setup on a GT86 shifts the handling balance towards that of a stock BRZ. I understand why @Lauren went for 5/6, with consideration of the extra grip from the improved camber control at the front I can see why its more playful at the rear though!

One important note is that all of this is best compared for steady-state (i.e. mid corner) balance, damper and alignment settings play a significant part in corner entry and corner exit characteristics. Carroll Smith's "Engineer in your Pocket" is a great read for this. http://www.carrollsmith.com/books/#pocketbook-detail

Feel free to ask if you have any questions about how the spreadsheet works.

Screenshot 2016-03-29 15.19.06.png

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A question for those on coilovers, particularly Teins. Did you fit shorter drop links? Are they necessary or can I just run the stock ones?

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8 hours ago, Rich said:

A question for those on coilovers, particularly Teins. Did you fit shorter drop links? Are they necessary or can I just run the stock ones?

I fitted adjustable ones yes. It's not necessary as such but it does allow you to set the arb preload properly. Also the stock ones can be a nightmare to remove.

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I've not changed my droplinks either, only had an issue of it knocking on full lock with the camber set to max dialled it down a bit now and all fine

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It depenfs how low you drop it. With my coilovers set to their recommended height, the roll bars were in roughtly the same place as stock with the stock drop links. If you plan to lower alot however you do need to be carefull as it full compression and a decent amound of lock the roll bar can get stuck and bind. In that case you'll need to lengthen the drop links.


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p.s. if you are going for drop links I strongly suggest you look at the whileline bars as the bar and droplink combo isnt much more than the droplinks on their own.

You can use Dans excellent spreadsheet to set them up to give roughly the same roll stiffness as with the standard bars.

Just a thought anyway. Thats what ill be doing.

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Just a quick question for the lowered daily drivers, what's a good height to go and still be able to tackle all the humps and bumps? I had coilovers on my last car and I had it ridiculously low and was pretty undrivable, I want to be able to drive it everywhere.

Sent from my E6853 using Tapatalk

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1 hour ago, Kirsty80 said:

Just a quick question for the lowered daily drivers, what's a good height to go and still be able to tackle all the humps and bumps? I had coilovers on my last car and I had it ridiculously low and was pretty undrivable, I want to be able to drive it everywhere.

Sent from my E6853 using Tapatalk

I'm now about 40mm down from the about 50mm I was before but I've gone with a 235/45/17 tyres which is larger than stock by 9mm so fills more of the arch gap and gives a good ride in combination with the flex a's.

20160407_160329_Hagrid_Clean_1.jpg

Only the absolute monster bumps are an issue now but it still removes the nasty arch gap.

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See now that's how I want mine to look, but still be practical. I love your wheels by the way they suit it well. I was just going to go for springs but I know I won't be happy with them never have on other cars.

Sent from my E6853 using Tapatalk

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10 minutes ago, Kirsty80 said:

See now that's how I want mine to look, but still be practical. I love your wheels by the way they suit it well. I was just going to go for springs but I know I won't be happy with them never have on other cars.

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Thank you!

I live in speed bump central and can cope with most of them now. The 40mm lowering and slightly higher profile tyre definitely seems a good mix for daily use.

If you come to the mids meet you're welcome to a good nosey! 😊

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Thanks for the info guys, with the coilovers at that height do I need to change anything else on the suspension? I've only had fixed axel cars before so it's all new to me.

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51 minutes ago, Kirsty80 said:

Thanks for the info guys, with the coilovers at that height do I need to change anything else on the suspension? I've only had fixed axel cars before so it's all new to me.

Sent from my E6853 using Tapatalk

Rear camber adjustment is useful either from lower arms or upper camber bushes.

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1 hour ago, will300 said:

@Kirsty80 lets put it this way, after myself and about 4 others had a passenger ride in Deacon's car we all went out and bought the same coilovers, the Tein Flex A and at £650 from @James@Amber they are reasonably priced.

think you've done a typo in your price, thought they were 750? although they are a bit more now, when I ordered mine with postage it came to 800

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On 07/05/2016 at 7:35 PM, Tareim said:

think you've done a typo in your price, thought they were 750? although they are a bit more now, when I ordered mine with postage it came to 800

Mine were about the same price as yours.

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Quick question.... Are adjustable drop links a 'must have' when changing suspension & lowering? Or can standards be used providing their in ok condition? Would they be needed for both front and back also? :huh:

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On 07/05/2016 at 4:45 PM, Deacon said:

I'm now about 40mm down from the about 50mm I was before but I've gone with a 235/45/17 tyres which is larger than stock by 9mm so fills more of the arch gap and gives a good ride in combination with the flex a's.

Does that affect the speedometer reading by much?

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