Cubits
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Wednesday, February 16, 2011 0:08 PM
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AW11 springs?
After seeing a few videos of adubs driving along lumpy mountain roads without being killed i've pretty much decided to dump my bc coilovers for a set of stock struts with konis and a nice set of springs.
I know the obvious choice is the eibachs, but i'd actually prefer a linear spring, and i need rates around 3-3.5kg and 4.5-5. If possible, i'd also like to keep the drop under about 3cm from stock.
I was considering doing a HSD kit like the one knightrous has, but corner-weighting isn't a priority for the driving i do.
Does anyone have the dimensions of the standard springs or can give a couple a quick measure for me? Some of the more reputable companies might have something in the right size.
So far all i've found are these, which may do the job:
http://www.fensport.co.uk/Parts/Model_22/Category_2/1601
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Domma_aw11
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RE: AW11 springs?
Wednesday, February 16, 2011 0:39 PM
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u dnt like the bc's?? i have a set for a couple months, i thought they were better than spings and koni yellows.. what rates did u have in the bc, i have 4kg front 6kg rear, its acctual more comfy ride than my stock s14...
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Cubits
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RE: AW11 springs?
Wednesday, February 16, 2011 0:59 PM
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I have no patience for progressive/linear damping, i NEED digressive dampers in my cars. The fact that my 205, when it had 110hp and stock suspension would DESTROY my s/c'd adub on my favourite roads is all of the proof i need. And when my stock 205 dampers finally carked i switched to koni's, which are also digressive, and they have always been fantastic.
I thought i could get by on these coilovers, but i just find them unbearable no matter how much i fiddle. They have no droop and the damping has no knee. I always knew the 5/8kg spring rates were absurd, but it's not the only problem.
I have no doubt that they would be pretty effective in autocross or for serious track work, but i'm essentially trying to build a targa car and need the ability to mow over unsighted bumps/holes without bouncing.
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MRTurbo
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RE: AW11 springs?
Wednesday, February 16, 2011 1:53 AM
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What is the benefit of digressive over linear/progressive? Don't the BC's have damper adjustment?? is it rebound only?
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Cubits
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RE: AW11 springs?
Wednesday, February 16, 2011 2:14 AM
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BC's have a combined bump/rebound adjustment, but if you tune out the high-speed brittleness you end up underdamped at low damper velocities. Koni's only have rebound adjustment, but tend to have very well matched stock valving (and good damping doesn't need to be adjusted).
Digressive damping has stiff low speed damping but is soft (relative to a linear relationship) in high speed damping. This means the car feels stiff in pitch and roll, but absorbs bumps/holes. It's how rally cars don't pitch and roll but demolish rutted roads. Most european performance cars have adopted this style of damping, but the japanese held on to progressive damping for longer (although they are coming around now). Motor/mountain bikes exclusively use this valving.
French hatchbacks and lotii use digressive damping (peugeot started making it standard in the 60's!), whereas honda type-r's use progressive (for instance). The honda will jiggle about and "feel" racier, and will still be fast on a circuit, but it won't have the consistency on lumpy roads. I think most aftermarket coilovers are deliberately progressive to make the car feel racier, digressive valving isn't really any more expensive. :p
Bilstein, KW, Ohlins, Koni, Penske all use digression. 99% of japanese/chinese/ebay coilovers are progressive.
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Knightrous
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RE: AW11 springs?
Wednesday, February 16, 2011 2:59 AM
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quote: Originally posted by Cubits I was considering doing a HSD kit like the one knightrous has, but corner-weighting isn't a priority for the driving i do.
What I plan on doing with my fronts (I've been saying this for 12months [xx(]) is buying the HSD springs ($100/pair, any spring rate) and just machining up some lower spring lands and tops to weld to the stock strut. I can probably do some corner weighting with locking spacers between the spring and the spring top if I wanted to go that far. If you know anyone with a lathe, you could make the spring lands/tops for the HSD springs for beer money. Machine steel spring land that can be welded to the strut out of a chunk of 10mm thick plate and machine an aluminium spring top out of 15mm thick plate. I'll have to dig out my CAD drawings for this
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MRTurbo
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RE: AW11 springs?
Wednesday, February 16, 2011 4:07 AM
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Very good info there Cubits - I definitely will stick to my good 'ol Koni's...the TIEN HR's (not mine) that are in ATM are shaking my car to bits over Adelaide's horrible roads. [V] That being said, I'd probably go Bilstein next time.
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Cubits
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RE: AW11 springs?
Wednesday, February 16, 2011 5:58 AM
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With a little modification (the addition of a valve), the non-adjustable bilsteins can be modified to be user-rebuildable! That means you could customise your own shim stack for perfectly tuned damping! Mmmmm...
Shame they don't do an adub unit.
Still though, it's hard to go wrong with konis. As long as you get them in matched pairs (and stay away from full soft/hard) they're pretty damned awesome, last a long time, and have a pretty good warranty behind them.
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MRTurbo
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RE: AW11 springs?
Wednesday, February 16, 2011 6:25 AM
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quote: Originally posted by Cubits
As long as you get them in matched pairs (and stay away from full soft/hard)
What do you exactly mean by this? Do you mean adjusting them to the same "firmness" on each axle?
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ZEROGK
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RE: AW11 springs?
Wednesday, February 16, 2011 6:39 AM
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No, he means buying two dampers that have been matched on a dyno by the supplier, so you don't end up with two dampers that have slightly different damping curves. Good luck getting a matched pair for an AW11 though. I doubt that any MR2 parts suppliers would have enough stock (or a dyno) to do this. It looks like Cubits has been busy reading articles at farnorthracing.com
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Cubits
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RE: AW11 springs?
Wednesday, February 16, 2011 6:49 AM
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quote: Originally posted by ZEROGK
No, he means buying two dampers that have been matched on a dyno by the supplier, so you don't end up with two dampers that have slightly different damping curves. Good luck getting a matched pair for an AW11 though. I doubt that any MR2 parts suppliers would have enough stock (or a dyno) to do this.
It looks like Cubits has been busy reading articles at farnorthracing.com 
Haha, that is where i saw the bilstein mod! Having revalved mountain bike suspension for years it was awesome to finally see a way to get that kind of freedom with car suspension relatively cheaply. I'd much rather have that than an adjustable bleed valve. Edit: I thought twosrus matched pairs, but it doesn't seem so. It wouldn't take much stock to get things within tolerance (koni's don't have too much variance around the lower end of the settings), but i guess they would need to actually dyno the things. :p
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Fab4mr2
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RE: AW11 springs?
Wednesday, February 16, 2011 9:10 AM
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The regular TRD drop springs are 2.9 front and 4.9 rear. Other than that Cusco used to make some that were actually somewhat stiffer, around 3.5-4 front and 5.5-6 rear. I saw a set on YJ last year, and though about grabbing them, but was a bit worried still about rates that high. As it is, I am using TRD gymkhanas now that are 2.5 front and 4.9 rear, and while I could use slightly stiffer rear rates I am not sure I would want much stiffer up front when it is used so much as a daily. I use KYB SSfS inserts, which are adjustable in both rebound and compression, and they are much stiffer at slow speeds than Konis are, so the lane dots, etc, can be a bit annoying when driving slow. At speeds they are fine.
If you want really great AW11 oem replacement struts though search real hard for a set of AW11 Ohlins. They are inverted, designed for road use, are 24-way adjustable, rebound and compression, and cover a huge range of spring rates. rebuilding them costs about what a new set of Koni's run. There is a set of front ones on YJ right now for about 42,500 yen, though they don't say what condition they are in, so that is probably a bit high yet.
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Cubits
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RE: AW11 springs?
Wednesday, February 16, 2011 9:57 AM
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Yeah, the ohlins are very very nice, but i doubt i could rustle up a complete set any time soon. I'll let those go through to someone who needs the adjustability. :p
I just fired an email off to Fensport enquiring about custom springs. Apparently they do them, at a sane price, and to a much higher quality than king springs. From my calculations, i will end up with a 15mm drop on 2.5kg/4kg springs with ride frequencies of 1.8/2.0Hz, which is bang on my upper limit and should give a very nice balance. I just need verification from them on their standard spring kit rates and how close they can get to my desired specs. :>
Seems soft, but it should be quite sharp with the dampers set correctly. After all, the Lotus elise runs at 1.5Hz and is hardly doughy! I had heard on the internet (dubious) that the MR2 Koni struts weren't revalveable, but that sounds like twaddle since even my 205 had that feature. I emailed Koni about this, so it should be interesting to see if i can make changes there. :D
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Fab4mr2
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RE: AW11 springs?
Wednesday, February 16, 2011 10:45 AM
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The standard aw11 Konis are not revalvable to my knowledge, mostly because Koni won't let anyone else work on them. Maybe the race ones though.
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Cubits
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RE: AW11 springs?
Friday, February 18, 2011 0:59 PM
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Just heard back from Koni. Apparently the oiriginal design of koni strut for the aw11 wasn't rebuildable, but that has since been addressed. ;)
Fensport also replied, they can do any rate requested at any free length desired.
Looks like this is the way to go. :)
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