Tire conundrum

[blacksheep-1]

That's basically how I make my living..lol

 

[jpt3]

I think this thread has quickly turned into a 'how to spend other people's money' thread.

This is my take:

Set the suspension up for the tires you want to run.

...

Anyway, I don't see the point in picking out bar sizes and other details until after you pick a direction on the suspension upgrades and the tires you want to run.

Hope that helps.

Excellent points!!!

Here are my goals. For now I want to keep my koni sport dampeners. I am open to changing the springs for better handling and would like to upgrade the sway bars.

As far as tires I plan to run these R888s until they're shot then start running pirelli takeoff.

With these items in mind what would you recommend?

 

[F.D. Sako]

It may be tough customizing spring rates with the stock spring sizes. Most aftermarket companies won't disclose their rates, and youre stuck with springs that are already out there. It's easier to customize spring rates with coilovers, since they use standard spring sizes.

If I were in your position, I'd get springs that have rates as close to the rates you want and fine adjust it with sway bars.

 

[Fabman]

Excellent points!!!

Here are my goals. For now I want to keep my koni sport dampeners. I am open to changing the springs for better handling and would like to upgrade the sway bars.

As far as tires I plan to run these R888s until they're shot then start running pirelli takeoff.

With these items in mind what would you recommend?

Go to ground control and get a coilover upgrade kit for your Konis and get the bars and springs previously mentioned. The coil over kit is cheap but you will have to use their springs as they have a unique ID. 500/350 35mm/18mm. Just do it, you're going to end up here anyway, why do it over?

 

[Grant 302]

Excellent points!!!

Here are my goals. For now I want to keep my koni sport dampeners. I am open to changing the springs for better handling and would like to upgrade the sway bars.

As far as tires I plan to run these R888s until they're shot then start running pirelli takeoff.

With these items in mind what would you recommend?

This route generally will mean first picking the springs, and 'fixing' the geometry from lowering, then working with sway bars to tune the bias.

How much lower are you willing to go from stock?

Most aftermarket companies won't disclose their rates

True, but many of the rates have been tested or measured. And most of the rates are functionally similar in the context of handling. The biggest difference is ride height, and at least this is published info.

...

Once the springs are chosen, then depending on the amount of drop, supporting suspension geometry changes can be made like LCA relocation brackets, LCAs if needed for said brackets. Likely caster camber plates. Maybe ball joints/bumpsteer kit if needed. Other mods to 'tighten' the relative slop, if desired. But all that after you figure out how low you want or are willing to go.

Go to ground control and get a coilover upgrade kit for your Konis and get the bars and springs previously mentioned. The coil over kit is cheap but you will have to use their springs as they have a unique ID. 500/350 35mm/18mm. Just do it, you're going to end up here anyway, why do it over?

And this is certainly something to consider. Added grip is addictive. Many of us *could* have left well enough alone...but how fun is that? That said there have been builds using Koni sports that work just fine for slicks.

 

[jpt3]

Go to ground control and get a coilover upgrade kit for your Konis and get the bars and springs previously mentioned. The coil over kit is cheap but you will have to use their springs as they have a unique ID. 500/350 35mm/18mm. Just do it, you're going to end up here anyway, why do it over?

This is interesting and within reason. I went to their site and I'm not 100% clear. I found the coilover conversion but wasn't sure about springs. Are you saying if I specify that exact spring they will fabricate it like that?

When it talks about retaining the stock perch what does that mean?

Great idea thanks

 

[jpt3]

This route generally will mean first picking the springs, and 'fixing' the geometry from lowering, then working with sway bars to tune the bias.

How much lower are you willing to go from stock?
True, but many of the rates have been tested or measured. And most of the rates are functionally similar in the context of handling. The biggest difference is ride height, and at least this is published info.

...

Once the springs are chosen, then depending on the amount of drop, supporting suspension geometry changes can be made like LCA relocation brackets, LCAs if needed for said brackets. Likely caster camber plates. Maybe ball joints/bumpsteer kit if needed. Other mods to 'tighten' the relative slop, if desired. But all that after you figure out how low you want or are willing to go.

And this is certainly something to consider. Added grip is addictive. Many of us *could* have left well enough alone...but how fun is that? That said there have been builds using Koni sports that work just fine for slicks.

You guys have knowledge way beyond mine when it comes to geometry and everything. At this point I have not done any relocation brackets or new LCAs. I guess it just helps get rid of some of the extra play and make things more precise?

 

[F.D. Sako]

incorrect geometry usually leads to un-neutral driving dynamics, such as snap oversteer, understeer, traction loss mid-turn, etc.

Usually, you want your control arms as parallel to the ground as possible, while taking acceleration/deceleration into consideration as well. Depending on how much you've lowered your car, the control arms can point up. So, you use LCA relocation brackets in the rear and extended balljoints up front to correct the geometry.

This is a high level summary, which is all i know :

 

[Grant 302]

You guys have knowledge way beyond mine when it comes to geometry and everything. At this point I have not done any relocation brackets or new LCAs. I guess it just helps get rid of some of the extra play and make things more precise?

Most aftermarket springs lower the car. That, in turn, screws up the suspension geometry.

incorrect geometry usually leads to un-neutral driving dynamics, such as snap oversteer, understeer, traction loss mid-turn, etc.

Usually, you want your control arms as parallel to the ground as possible, while taking acceleration/deceleration into consideration as well. Depending on how much you've lowered your car, the control arms can point up. So, you use LCA relocation brackets in the rear and extended balljoints up front to correct the geometry.

This is a high level summary, which is all i know :

Covered the important parts right there. 8)

...

Most aftermarket parts also reduce unwanted play where stock parts have big, soft rubber bushings. Smaller rubber, urethane, or heim joints are often used in aftermarket parts. How tight you want it is up to you.

 

[Fabman]

This is interesting and within reason. I went to their site and I'm not 100% clear. I found the coilover conversion but wasn't sure about springs. Are you saying if I specify that exact spring they will fabricate it like that?

When it talks about retaining the stock perch what does that mean?

Great idea thanks

You order the spring rates you want when you order the coilover kit.
Call ground control and they will give you a quick tutorial on how they work.
I was just about to pull the trigger on these when I opted for Cortex coilovers at the last minute.
Word to the wise (as previously mentioned) don't go crazy with lowering the car, especially with Konis.
The shocks will bottom and then you have NO suspension not to mention all the bad geometry that happens.
Plus, you can blow the shocks, and that's baaad mkay?
You are going to have some wheel travel, make sure there is enough.

 

[blacksheep-1]

Well since Grant brought up spending money, and the Boss/Gt cars aren't bad platforms to begin with, probably the best place to find speed is to attend a driver's school. Everyone, including me, intends to focus on the car when the driver is usually the weakest link at first.
Rarely is money spent on a driver school ever wasted.

Also FWIW, we run a ton of ride height, the Porsche guys we ran with last year were making fun of it since they can put their entire shoe under the front of the car....then the race started.
I'll see if I can find a pic. Keep in mind that to get one of these cars to stick the suspension needs to move, I think one of the pitfalls guys get into is they restrict the movement of the car's suspension. Again, we rarely, if ever, use LCA relocating brackets.

 

[Grant 302]

Agreed and agreed.

Even with coilovers, I don't lower my front on the GT more than stock boss geometry. Slamming the front creates more issues to 'fix'.


Instruction and quality seat time are *always* valuable. A good driver eeks out the most of what's there in a car. I know I 'overdrive' my cars and start to see what hardware can be improved. : :-[ FWIW, this is one reason why my Boss is stock except for cooling mods.

 

[Mad Hatter]

Hmmm... interesting......

About the driver.... That is so true!!.... Go to the same track a dozen times and have the same time every event. Feel like its the car thats holding you back.... then you change a shift point and push a little harder, then your time comes down 1.5 seconds. Then all the ideas (excuses!) you had about your car go up in the air and you start again.....

 

[Bill Pemberton]

If you call Tire Rack , ask for Luke Pavlik ( ext #4362 ) , he has been helping a lot of track guys since around 1999.

 

[jpt3]

Well since Grant brought up spending money, and the Boss/Gt cars aren't bad platforms to begin with, probably the best place to find speed is to attend a driver's school. Everyone, including me, intends to focus on the car when the driver is usually the weakest link at first.
Rarely is money spent on a driver school ever wasted.

Also FWIW, we run a ton of ride height, the Porsche guys we ran with last year were making fun of it since they can put their entire shoe under the front of the car....then the race started.
I'll see if I can find a pic. Keep in mind that to get one of these cars to stick the suspension needs to move, I think one of the pitfalls guys get into is they restrict the movement of the car's suspension. Again, we rarely, if ever, use LCA relocating brackets.

This truly is great advice especially with me being newer to this sport. I was fortunate enough to be able to spend two days with Ross Bentley in the fall and it was incredible. It was a large investment but well worth it. I felt like I gained a years experience in a few days. I also spoke with Bertil Roos today about doing their advanced driving school.

With all that said I want my car performing well and balanced without going crazy. My five year goal is to have a dedicated track car so I don't want to go insane with my car right now.

I like the idea of working on the spring rate and changing to the ford racing bar. This had turned into an amazing thread!

 

[Grant 302]

Speaking of which...maybe we should focus on the adjustments to make for your next track day? Lower pressure, more camber, fix the squat in the rear.

 

[jpt3]

Speaking of which...maybe we should focus on the adjustments to make for your next track day? Lower pressure, more camber, fix the squat in the rear.

Haha funny how that happens. So here are my plans thus far: go from -2 degrees to -2.5 or -3. Lower tire pressures. Lastly the squat? Do you mean the body roll I showed? I am thinking about doing the coil over conversion.

 

[Grant 302]

Haha funny how that happens. So here are my plans thus far: go from -2 degrees to -2.5 or -3. Lower tire pressures. Lastly the squat? Do you mean the body roll I showed? I am thinking about doing the coil over conversion.

I mean to fix the 'squat' geometry in the rear. You 'need' rear LCA relocation brackets. There are some that can work with stock arms, but it's probably a good time to upgrade those too. Just gotta figure out how stiff you want to go with the bushings. I'd try to stick with the same brand arms and brackets.

And that's something you should do anyway if you're doing coilovers in the future, and can still help your setup right now.

 

[jpt3]

Black boss what are your thoughts on the LCA brackets and LCAs. You said you don't run the brackets? Why is thet


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[Grant 302]

...I think you mean @blacksheep-1