Topic: Optimizing Spring Rates

[Black Magic]

Thanks for the link to the sway bar information Ag_Sky but in stock classes we can only play with the FSB.  I did check out the link and didn't see what the spring rates were for the different suspension packages (FE2 to ZOK).  I do have those numbers written down and need to find them.

Our basic balance was established long ago through alignment,  shock settings, and adjusting tire air pressures.  As stated previously we have a third hole drilled in the FSB to make the front bar stiffer than stock.  We fine tune the setup at each race as our balance dictates.

I am interested in having a blade type front bar made but haven't found a stock ZOK bar to modify.  It hasn't been a priority in any way but the blade can be tuned to quickly change the FSB rates. 

When I checked out the link you provided I did see that FastMike posted there.  Mike is the guy who ran the 600/600 combination on his ZOK Solstice.  He won some tour events in STR with that combination.  He is very experienced and might be another good resource for any questions you might have. 

For sure your Hankook RS-3's do not like cold temps and they are much better suited for the heat of summer conditions.  If you have a budget for tires you might want to consider the Dunlop Z11 in 255 width for STR.  For national tours and pro's we run C/S with 285 Hoosiers on 8 by 18 wheels.  For local RTR class the Dunlop Star Spec 265's have given us 350 great runs so far and are still fast with quite a bit of tire life left.  We also have a new set of 275 Rivals that have proven to be a bit slower than the new set of Dunlop Z11's that are also 265's like the great Star Specs.

Bottom line is that I wouldn't be too hasty to change the springs on your car without at least a full day of testing.   I think you can find balance with whatever spring rates you choose.  You can achieve the balance that fits your driving style if you use all the adjustment techniques that you have at your disposal. 

Did Koni know you were buying the Sports to control the 700/900 spring rates?  Is there any way that you can test your springs again this season?

[Ag_Sky]

... didn't see what the spring rates were for the different suspension packages (FE2 to ZOK)....

Here's the spring rates for the stock suspension codes.

... If you have a budget for tires you might want to consider the Dunlop Z11 in 255 width for STR.  For national tours and pro's we run C/S with 285 Hoosiers on 8 by 18 wheels.  For local RTR class the Dunlop Star Spec 265's have given us 350 great runs so far and are still fast with quite a bit of tire life left.  We also have a new set of 275 Rivals that have proven to be a bit slower than the new set of Dunlop Z11's that are also 265's like the great Star Specs...

That's good to know about the tires. I have been considering a different tire for next season.

...Bottom line is that I wouldn't be too hasty to change the springs on your car without at least a full day of testing.   I think you can find balance with whatever spring rates you choose.  You can achieve the balance that fits your driving style if you use all the adjustment techniques that you have at your disposal....

I agree, but I have a hard time finding the time and place to do a lot of testing.

...Did Koni know you were buying the Sports to control the 700/900 spring rates?  Is there any way that you can test your springs again this season?

I talked to Koni about using the SA with 1200 lbf/in springs and the guy said they would work, but they would need to be set at their stiffest setting. I'm pretty much done for season.

How are your times compared to Fast Mike's?

[elff]

If only someone had created a comparison thread

http://www.kappaperformance.com/forum/index.php/topic,8724.0.html

[GXP_Matt]

Thanks for the link to the sway bar information Ag_Sky but in stock classes we can only play with the FSB.  I did check out the link and didn't see what the spring rates were for the different suspension packages (FE2 to ZOK).  I do have those numbers written down and need to find them.

Our basic balance was established long ago through alignment,  shock settings, and adjusting tire air pressures.  As stated previously we have a third hole drilled in the FSB to make the front bar stiffer than stock.  We fine tune the setup at each race as our balance dictates.

I am interested in having a blade type front bar made but haven't found a stock ZOK bar to modify.  It hasn't been a priority in any way but the blade can be tuned to quickly change the FSB rates. 

When I checked out the link you provided I did see that FastMike posted there.  Mike is the guy who ran the 600/600 combination on his ZOK Solstice.  He won some tour events in STR with that combination.  He is very experienced and might be another good resource for any questions you might have. 

For sure your Hankook RS-3's do not like cold temps and they are much better suited for the heat of summer conditions.  If you have a budget for tires you might want to consider the Dunlop Z11 in 255 width for STR.  For national tours and pro's we run C/S with 285 Hoosiers on 8 by 18 wheels.  For local RTR class the Dunlop Star Spec 265's have given us 350 great runs so far and are still fast with quite a bit of tire life left.  We also have a new set of 275 Rivals that have proven to be a bit slower than the new set of Dunlop Z11's that are also 265's like the great Star Specs.

Bottom line is that I wouldn't be too hasty to change the springs on your car without at least a full day of testing.   I think you can find balance with whatever spring rates you choose.  You can achieve the balance that fits your driving style if you use all the adjustment techniques that you have at your disposal. 

Did Koni know you were buying the Sports to control the 700/900 spring rates?  Is there any way that you can test your springs again this season?

As of 2011 or 2012 (can't remember) you can change either the front or rear sway bar in stock classes.  I also run the Dunlop Z2's on my stock class GXP but I prefer the 245/40 size for 8" wheels.  Street tires don't have nearly the sidewall stiffness that Hoosiers do, so you can't overtire nearly as much.  I bet if you try out the 245 Rivals they will be much closer than the 275s were to the Z2's.  I'm even thinking of trying the 245s Rivals up front with 245 Z2's out back since the Z2's put down power well but are peaky in terms of lateral grip.

[Black Magic]

Had the wheels off the car this weekend and discovered that there is a third hole was in the end of the bar.  My bad.  The hole was for a softer than ZOK setting.  When we started with the Solstice in late 08 I saw posts from autocrossers who thought the front end was too stiff and some even swapped to the FE2 FSB.  That has never been the case for us.  Bottom line is our bar is in the stiffest inboard  position.

Don't know if the FE3 ZOK front bars have 1 or 2 holes in the stock configuration.  If the stock bar comes with only 1 hole then we do have a stiffer than stock ZOK inboard hole in the FSB.

[Black Magic]

To be clear, these are LE5 Z0k parts (aka FE3 LNF), not LNF Z0k, correct?  So 33.3 x 4.5mm wall FSB and 25.4 x 3mm rear? 

Interesting that you went with stiffer front instead of rear as is common around here.  I prefer the LNF Z0k rear bar to the FE3 for autocross since it improved corner entry so much without seeming to give up much on exit, but I guess with custom valved Penske's you can change the balance significantly...
[/quote

Hey Matt.  See you are the RTR 2013 Champion in your division.  Congratulations.  Your B/S PAX doesn't make it easy.
It looks like there is a stiffer 6mm wall instead of the 4.5 wall that is FE3 stock ZOK.   I would like to get a 6mm thickness FSB to help with looseness. 

One would think that our car is always pretty close but the car went from spot on in Lincoln on Hoosiers to pretty loose when we ran the car in RTR locally after the Nationals with the same shock settings.   

Is the LFN ZOK rear bar STIFFER than the FE3 ZOK RSB? 

[Black Magic]

As of 2011 or 2012 (can't remember) you can change either the front or rear sway bar in stock classes.  I also run the Dunlop Z2's on my stock class GXP but I prefer the 245/40 size for 8" wheels.  Street tires don't have nearly the sidewall stiffness that Hoosiers do, so you can't overtire nearly as much.  I bet if you try out the 245 Rivals they will be much closer than the 275s were to the Z2's.  I'm even thinking of trying the 245s Rivals up front with 245 Z2's out back since the Z2's put down power well but are peaky in terms of lateral grip.

I screwed up the last post but my reply is in the Quote part.  I have never exchanged racing information online very much so I am not up to speed on how to use the message system.

Yes they did change that rule but we never considered changing our rear bar.  I wanted a very adjustable blade type FSB and that will be a 2014 project.

You might be right about the 245's being better than the over tired 275 Rivals.  The first set of street tires I bought in early 2012 were 265 Star Specs.  They were fantastic and still are the last time we ran them in practice.  They have over 350 runs on them and have lots of life left.  So it was logical that we would just get the same size in Z11's.  When the Rivals came out we wanted to find out if the Rival was faster than the Z11.  The Rivals only come in 245 or 275 and it looks like the 275 isn't happy on a 8 inch wheel and I made a bad guess. 

We still need to do more testing with the Rivals.  I was running for the RTR championship here and didn't want to fool around too much with the Rivals.  We have one more race but I am now the RTR 2013 champ here like you are there.

[Black Magic]

Here's the spring rates for the stock suspension codes.


That's good to know about the tires. I have been considering a different tire for next season.

I agree, but I have a hard time finding the time and place to do a lot of testing.

I talked to Koni about using the SA with 1200 lbf/in springs and the guy said they would work, but they would need to be set at their stiffest setting. I'm pretty much done for season.

How are your times compared to Fast Mike's?

Do you have a big parking lot that you could use for a skid pad?  More than likely you could balance your 700/900 spring setup easily.  Good to know that Koni says that IF you have 1200 springs you need to be FULL stiff but at 700/900  you can use less than full stiff in the front and rear rebound adjustments. 

Fast Mike lives in the Seattle area.  I am in southern California.  As far as times are concerned I would say that Mike is faster than I am BUT I don't think there is anybody in the world that is faster than my co driver. 

[Ag_Sky]

...Fast Mike lives in the Seattle area.  I am in southern California.  As far as times are concerned I would say that Mike is faster than I am BUT I don't think there is anybody in the world that is faster than my co driver…..

I was curious about FM because he use to drive a Solstice, but switched to a S2000. If you and your co-driver are close to FM's times I'd take that as a positive meaning the Kappa platform still might be competitive in STR.

[Black Magic]

I was curious about FM because he use to drive a Solstice, but switched to a S2000. If you and your co-driver are close to FM's times I'd take that as a positive meaning the Kappa platform still might be competitive in STR.

FM still has his ZOK Solstice.  The S2000 was probably as co drive with Kevin Deitz.  I have no doubt that my co driver could/would  win in STR but it also takes a fair amount of money to prepare and our disposable income has dropped significantly the last few years.   I figured it would cost 18K to prep our 99 Miata for STR and have never seriously looked at how much it would take to prep the Solstice for STR.   I have 2 cars sitting in our driveway that are both C/S National Champions.  It has always been my contention that the Miata and Solstice/Sky are C stock cars do not belong with A stock S2000's in STR. 

[GXP_Matt]

I screwed up the last post but my reply is in the Quote part.  I have never exchanged racing information online very much so I am not up to speed on how to use the message system.

Yes they did change that rule but we never considered changing our rear bar.  I wanted a very adjustable blade type FSB and that will be a 2014 project.

You might be right about the 245's being better than the over tired 275 Rivals.  The first set of street tires I bought in early 2012 were 265 Star Specs.  They were fantastic and still are the last time we ran them in practice.  They have over 350 runs on them and have lots of life left.  So it was logical that we would just get the same size in Z11's.  When the Rivals came out we wanted to find out if the Rival was faster than the Z11.  The Rivals only come in 245 or 275 and it looks like the 275 isn't happy on a 8 inch wheel and I made a bad guess. 

We still need to do more testing with the Rivals.  I was running for the RTR championship here and didn't want to fool around too much with the Rivals.  We have one more race but I am now the RTR 2013 champ here like you are there.

Awesome, good to hear on the RTR champ and thanks for coming on here and sharing your information!  Not too many Kappas running at a National level any more so it's always good to hear from others that still are.  You and your co-driver have done some awesome work at Nats the past couple years in CS, still planning to run CS next year or go to B-Street?

[Black Magic]

Thanks Matt.  Our stock Solstice with ZOK package added is being moved to B-street along with the ZOK's and Miata MS-R's by the volunteer SEB board.  I thought we would just remove the ZOK stuff and stay in C-street with our stock Solstice but because of who we are the SEB moved us too.  The stock MX5 Miata does stay in C-street like I thought we should. 

Does your GXP stay in B-street in 2014?   

Michael Heinitz (won RTR in Lincoln) with a 07 MS-R  thinks the Solstice is the car to have in B-street.  If we would have chosen to keep on running with the SCCA we would have been the car to beat.  If we wanted to run in E-street with our 99 Miata that was the 07 C/S National Champion that beat the ZOK's and MS-R's I think it's safe to say we would be the car to beat there too.  I am finished with stock classes and probably with the SCCA too. SEB decisions are arbitrary and convoluted.  That is why I am here to gain information about spring rates.   

When the classing reorganization hit last year I decided that it was time to quit running in stock classes that are always being jacked around by the SEB.  This was the reason our car showed up in Lincoln this year with the tires that we ran at the San Diego Tour.  I knew we were not going to run C/S again and wanted to save the $1500. for tires and use that money to start making our Solstice better. 

I campaigned for the Solstice to be classed in STX that I thought was the right class.  The RX8 that went from a 5 time Natl champion B/S car to C/S is allowed to run in STX as is the FRS/BRX C/stockers.  Since we run in a high visibility region with many national people watching what we do for the last 9 years I pretty much knew that wasn't going to happen.  My co driver straight times 2 top national STX cars with our car on street tires. 

It took a combination of several factors to not make it 3 for 3 in National  Championships but the .1 loss in September happened.  It took the point and shoot East course, 332 HP, 10 inch rear wheels and 9 inch front wheels with new tires and a good driver to win by picking up a .9 on his last run.  Of course the 370Z is heavier but it has 155 more ponies up front.  I predict that next year C-street will beat B-street.  Time will tell.

Talking about RTR.  Here are the first 3 RTR entries for our last event.  We had 16 entires. 

1.  #20.  Me    in our      2011 National C/S Champion that was also the #1 PAX Stock car.
2.  #28   James Yom      2013 National B/S Champion
3.  #73   Michael Heinitz 2013 National RTR Champion

I ended up winning RTR and it cinched the 2013 championship here.  James ran a different class in the morning and Michael didn't show up but to make a long story short we always have tough competition here.