OEM Boss springs+ Koni's on a GT/Brembo car?

Mineral_01'

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Like the title says, anyone ever try the stock/OEM Boss 302 spring setup with Koni Sports on a GT or Track Pack/Brembo car?

Looking to increase coil rate over my stock Brembo springs and keep pretty much stock ride height for correct suspension geometry. Guys over on the Boss forums are having great success with their stock springs and Koni's so I figured why not try it on a GT/Track Pack car. Going this route will be a hell of a lot cheaper than going aftermarket for the springs too. I can get all 4 springs plus new strut mounts for $154 plus shipping. Also, staying near stock height, I will not need relocation brackets or adjustable PHB.

Anyone see any issues with this setup?
 

lsxjunkie

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Like the title says, anyone ever try the stock/OEM Boss 302 spring setup with Koni Sports on a GT or Track Pack/Brembo car?

Looking to increase coil rate over my stock Brembo springs and keep pretty much stock ride height for correct suspension geometry. Guys over on the Boss forums are having great success with their stock springs and Koni's so I figured why not try it on a GT/Track Pack car. Going this route will be a hell of a lot cheaper than going aftermarket for the springs too. I can get all 4 springs plus new strut mounts for $154 plus shipping. Also, staying near stock height, I will not need relocation brackets or adjustable PHB.

Anyone see any issues with this setup?

I plan on doing the same when my LS shocks blow. The rears are 5lbs softer than the LS and the fronts are 11lbs stiffer, both of which are things that I want. Also, the Konis are rebound adjustable only, whereas the the Tokicos tie compression and rebound together into one adjustment, which actually eliminates the ability to tune the handling to your liking. This is how my car sits with the LS springs, and how your car will sit with the Boss springs.

16319_10104116292428859_1854612383978196546_n.jpg
 

poof100

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I plan on doing the same when my LS shocks blow. The rears are 5lbs softer than the LS and the fronts are 11lbs stiffer, both of which are things that I want. Also, the Konis are rebound adjustable only, whereas the the Tokicos tie compression and rebound together into one adjustment, which actually eliminates the ability to tune the handling to your liking. This is how my car sits with the LS springs, and how your car will sit with the Boss springs.

16319_10104116292428859_1854612383978196546_n.jpg

Car looks good with the Wheels man! Glad they worked out for you. Thanks again!
 

Mineral_01'

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I plan on doing the same when my LS shocks blow. The rears are 5lbs softer than the LS and the fronts are 11lbs stiffer, both of which are things that I want. Also, the Konis are rebound adjustable only, whereas the the Tokicos tie compression and rebound together into one adjustment, which actually eliminates the ability to tune the handling to your liking. This is how my car sits with the LS springs, and how your car will sit with the Boss springs.

Thank you so very much for posting the picture of your OW Track pack car. It looks absolutely amazing. I would buy the springs alone just for the stance/rake. The added stiffness is a huge bonus too. Ordering the boss springs tonight. Thanks!
 
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86Fbody

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I might hold off until you talk with someone about the mating of those springs to the shocks, might be bouncy since the Boss springs are a little soft compared to the P or K springs that people usually pair the Koni's to.
 

Mineral_01'

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I might hold off until you talk with someone about the mating of those springs to the shocks, might be bouncy since the Boss springs are a little soft compared to the P or K springs that people usually pair the Koni's to.

I do not believe it will be an issue, as Boss owners over on another forum upgrade from their stock Tokico's to Koni's all the time with very positive results.
 

Mineral_01'

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lsxjunkie,

I noticed that you are running the boss rear sway bar in addition to the springs and shocks. Did you swap the rear bar because you went staggered just like the OEM Boss or did you feel it was needed to dial in more oversteer with a squared setup as well?
 

Locotone07

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Like the title says, anyone ever try the stock/OEM Boss 302 spring setup with Koni Sports on a GT or Track Pack/Brembo car?

Looking to increase coil rate over my stock Brembo springs and keep pretty much stock ride height for correct suspension geometry. Guys over on the Boss forums are having great success with their stock springs and Koni's so I figured why not try it on a GT/Track Pack car. Going this route will be a hell of a lot cheaper than going aftermarket for the springs too. I can get all 4 springs plus new strut mounts for $154 plus shipping. Also, staying near stock height, I will not need relocation brackets or adjustable PHB.

Anyone see any issues with this setup?

Tried this combo on my 2012 GT vert. The best description of the ride was "jittery" even after shock adjustments, but what I could not live with was the moderate drop in suspension height which caused my BOSS splitter to scrape any driveway I came down from, so I went back to the stock springs.
 

Mineral_01'

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Tried this combo on my 2012 GT vert. The best description of the ride was "jittery" even after shock adjustments, but what I could not live with was the moderate drop in suspension height which caused my BOSS splitter to scrape any driveway I came down from, so I went back to the stock springs.

Interesting and thank you for taking the time to reply. Curious as to what your exact setup was? Boss springs, koni's and factory sways and wheel arrangement? Going to the Boss springs is not that much more coil rate than the Brembo/TP cars, wonder why you couldn't get the dampers to control those springs?
 

Locotone07

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Interesting and thank you for taking the time to reply. Curious as to what your exact setup was? Boss springs, koni's and factory sways and wheel arrangement? Going to the Boss springs is not that much more coil rate than the Brembo/TP cars, wonder why you couldn't get the dampers to control those springs?

Non-Brembo, factory sways, 255/40-19 all around.
 

86Fbody

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I do not believe it will be an issue, as Boss owners over on another forum upgrade from their stock Tokico's to Koni's all the time with very positive results.

I would want to read that forum if you can supply it, I highly doubt anyone would upgrade the shocks and keep the stock springs. 1. That is really a waste of money since you won't get the most out of the upgrade, and 2. I don't think the valving of the Koni's would work well with the stock Boss springs as the springs are probably too soft and will cause a bouncy ride or like Locotone07 said, jittery. You are increase the rebound and compression but keeping the spring rate the same so the shocks will overpower the springs.
 
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Mineral_01'

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I would want to read that forum if you can supply it, I highly doubt anyone would upgrade the shocks and keep the stock springs. 1. That is really a waste of money since you won't get the most out of the upgrade, and 2. I don't think the valving of the Koni's would work well with the stock Boss springs as the springs are probably too soft and will cause a bouncy ride or like Locotone07 said, jittery. You are increase the rebound and compression but keeping the spring rate the same so the shocks will overpower the springs.

I took that information from this thread: http://www.boss302forum.com/topic/16136-koni-yellows/

Some quotes:

"I put in the koni yellows set at 1 turn off soft and crash bolts to get -2 deg camber. I have an adjustable rear sway from sam strano performance and run it full soft. My tires are Hankook Ventus r-s3 275/35r19 square on stock rims. The ride and handling is absolutely breathtaking - the car is even more of a monster than it was before."
"stock springs ... i am trying to keep the car as stock as possible. Only change left is the barton shifter bushing and the whiteline trans bushing insert. I am tired of missing the 2-3 shift."


All that aside, you do make some valid points about the sports. So you might say the Koni Str.t's better matched to boss springs?
 

86Fbody

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Those may be a better suited but I would check with maybe Jay at Hypermotive and see what he has to say about it.
 

lsxjunkie

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lsxjunkie,

I noticed that you are running the boss rear sway bar in addition to the springs and shocks. Did you swap the rear bar because you went staggered just like the OEM Boss or did you feel it was needed to dial in more oversteer with a squared setup as well?

I wanted more transition stiffness and it was cheap. If I were to do it over, I'd go with the stock rear bar and a stiffer front bar. Steady state cornering, I haven't pushed the car hard enough to know which end is going to wash out first. The mountain roads around here are too tight for that.

Tried this combo on my 2012 GT vert. The best description of the ride was "jittery" even after shock adjustments, but what I could not live with was the moderate drop in suspension height which caused my BOSS splitter to scrape any driveway I came down from, so I went back to the stock springs.

Boss 302 front and rear springs and Koni Yellows? Can you describe this jittery feeling better? Would the car skip over bumps? Was the problem coming from the front or the rear? What did you have your shocks set at? The Boss springs are much stiffer in the rear than in the front, and I'm wondering if I shouldn't go with the 55D springs in the rear instead to get the car at the height I want it but with a softer rate to match the front.

I would want to read that forum if you can supply it, I highly doubt anyone would upgrade the shocks and keep the stock springs. 1. That is really a waste of money since you won't get the most out of the upgrade, and 2. I don't think the valving of the Koni's would work well with the stock Boss springs as the springs are probably too soft and will cause a bouncy ride or like Locotone07 said, jittery. You are increase the rebound and compression but keeping the spring rate the same so the shocks will overpower the springs.

Boss springs are 148 front and 186 rear. There are hundreds of people using Koni Yellows with BMR's springs, which are 165F and 165 R. Sam Strano ran Koni Yellows on his autocross Brembo car with stock springs, at 131F and 167R initially. I really don't think that the spring rate is too soft for the additional compression damping in the Koni Yellows. The Laguna Seca shocks are stiffer on both compression and rebound than the base Boss 302 shocks, but the front springs are 11lbs softer.

Additionally, both the Steeda Sports and the Steeda Ultralites, which are sold by Sam Strano as a package with the Konis, come with a 175lbs rear spring, softer than both the Boss (186) and the LS (191) rear spring.


See also, this thread.

http://www.svtperformance.com/forums/showthread.php?893081-koni-yellows-w-stock-brembo-springs

However, be careful in there, because some people use Boss springs to refer to OEM boss springs, like Highway Star, and some people use Boss springs to refer to the Steeda Boss springs, which are a drop spring and significantly stiffer.

At the end of the day, I just wish someone would sell a spring at BMR rates with the Boss drop. I need the ground clearance and I do NOT want to mess with pinion angle. Also, I do not want a progressive rate spring.
 
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86Fbody

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That is all true, just figured OP should get an educated response from someone as to what may happen before blowing money and ending up unhappy. On the BMR springs and Koni's they are stiffer in the front and more pliable in the rear so they aren't softer all around, and in Strano's case I doubt he runs in an unlimited class otherwise his car wouldn't be competitive so he may have to make due with the springs he can use, and I doubt he DD's that car so bouncing probably isn't going to bother him.
 
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Mineral_01'

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lsxjunkie,

Thank you once again for replying in here. I love the information and opinions being tossed around in here. I hate having to bounce around to several different forums to find some conclusions.

Anyway, I have to agree with pretty much everything you said. I too and I'm wondering if I shouldn't go with the 55D springs in the rear instead of the stiff Boss 302's. I am also wondering between the Boss 302 fronts or the LS versions. The LS springs are very close to stock 137lb compared to stock 131lb. My thoughts are to go with the Boss 302 fronts (148lb) to do pretty much the same thing as adding a bigger front sway with the LS versions as you did.

So many different combinations to consider. This is beginning to make my head hurt...

I think you said it best too, "At the end of the day, I just wish someone would sell a spring at BMR rates with the Boss drop. I need the ground clearance and I do NOT want to mess with pinion angle. Also, I do not want a progressive rate spring. " If a product existed just as you described this thread would be /thread.
 

BMR Tech

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There is some solid info in here!

The Koni's work well with ALL springs, in the range of 125lb/in to 260lb/in up front, and 145lb/in to 260lb/in in the rear.

That said, using the Koni's with <200lb/in springs can, and will cause somewhat of a "jittery" ride.

Koni compression valving is very aggressive. The Yellows, and the STR.T's.

The Koni's are great. Quality, service, and performance - but, I do not like the ride quality. That is just me though.

So my point is, it is not necessarily the spring choice within these combos that makes for those ride characteristics.....but it is the struts and shocks. Now, when you go to a super stiff spring....that is when the blame game starts swaying towards the springs themselves.
 

BMR Tech

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I forgot to add.....the Boss/Koni set-up is a great set-up.....especially when you go with a stiffer front bar.

Myself, I like the rear spring rate a lot of the Boss....but not so much of a fan of running the front rate in the 140-150 range.
 

Mineral_01'

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There is some solid info in here!

The Koni's work well with ALL springs, in the range of 125lb/in to 260lb/in up front, and 145lb/in to 260lb/in in the rear.

That said, using the Koni's with <200lb/in springs can, and will cause somewhat of a "jittery" ride.

Koni compression valving is very aggressive. The Yellows, and the STR.T's.

The Koni's are great. Quality, service, and performance - but, I do not like the ride quality. That is just me though.

So my point is, it is not necessarily the spring choice within these combos that makes for those ride characteristics.....but it is the struts and shocks. Now, when you go to a super stiff spring....that is when the blame game starts swaying towards the springs themselves.

Thanks for coming in here too Kelly.

So which damper/shock do you think is suited best for linear springs with rates less than 200lb/in?
 

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