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Need help with Spring Rates and set up on my NA Fat Cat suspension

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Old 11-17-2017, 06:30 PM
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If you're under steering all over the place with 600/400 you're either driving way too deep and making the car understeer with your driving (needs moar drive mod) or you're just all over the front bump stops so your actual spring rate in the front is 2000.
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Old 11-20-2017, 03:18 PM
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Originally Posted by Leveq
I don't know where those 1000+/500 comparisons are coming from.
Years of experience, track records and national championships.
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Old 11-20-2017, 07:30 PM
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Please continue to tell us all how wrong we are, though. It's very endearing.
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Old 11-20-2017, 08:36 PM
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I'm wondering, though, if one can run 800/500 on non-adjustable revalved shocks.

My interest is that there seems to be a rule opportunity in Chumpcar where this would be possible, it should fit over the 2x rule (so 25pts per corner) but not pay the 75pts per corner of adjustables shocks.

Would a Fat Cat setup then be the way to go for a decent dual duty car between Time Attack and Chump? Is there any other possibilities for revalving them? I've got word of Whitener Racing Shocks.
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Old 11-20-2017, 08:39 PM
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The fat cat set up uses revalved Bilsteins . They are not adjustable but you have the problem with springs that I have been trying to figure out here- with some great suggestions
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Old 11-20-2017, 08:54 PM
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Originally Posted by Dalardan
I'm wondering, though, if one can run 800/500 on non-adjustable revalved shocks.
Yes, sure. You would just need to set the valving internally to match the spring rates.
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Old 11-20-2017, 09:07 PM
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Originally Posted by Leafy
If you're under steering all over the place with 600/400 you're either driving way too deep and making the car understeer with your driving (needs moar drive mod) or you're just all over the front bump stops so your actual spring rate in the front is 2000.
Or shitty m.net alignment
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Old 11-21-2017, 12:15 AM
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Originally Posted by FatKao
Years of experience, track records and national championships.
Way to quote out of context. Reading is hard.

Anyhow, seems like people here love to get offended.
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Old 11-21-2017, 07:02 AM
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You're right reading is hard, you were trying to say because you were on street/DOT tires that the 1000/500 comparison was invalid...... It's not, that is what the fast guys are running and you continue to ignore that fact.
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Old 11-21-2017, 08:45 AM
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Originally Posted by Bronson M
You're right reading is hard, you were trying to say because you were on street/DOT tires that the 1000/500 comparison was invalid...... It's not, that is what the fast guys are running and you continue to ignore that fact.
....and basic aero.

Is the 800-500 setup now past its fame ? Getting hard to follow
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Old 11-21-2017, 04:47 PM
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Originally Posted by Leveq
....and basic aero.

Is the 800-500 setup now past its fame ? Getting hard to follow
On a 245/40 RivalS-shod track car with no aero, I would start at 1000/500, yes. It would work at 800/500 as well, but it will go faster with 1000/500. It would be an undriveable mess at 600/400.

It is simply the progression of development on the chassis as tire technology improves. As tire grip increases, so must front roll stiffness.
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Old 11-21-2017, 06:28 PM
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Originally Posted by Savington
On a 245/40 RivalS-shod track car with no aero, I would start at 1000/500, yes. It would work at 800/500 as well, but it will go faster with 1000/500. It would be an undriveable mess at 600/400.
It is simply the progression of development on the chassis as tire technology improves. As tire grip increases, so must front roll stiffness.
Indeed. Need some power to get those 245s working tho. Ill keep my 205s for now lol... Either way I never put in question what rates work best, just what is deemed "undriveable" depending on what kind of build we're talking about.
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Old 11-24-2017, 12:12 AM
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Originally Posted by Leveq
Indeed. Need some power to get those 245s working tho. Ill keep my 205s for now lol... Either way I never put in question what rates work best, just what is deemed "undriveable" depending on what kind of build we're talking about.
A fair amount of people running 245s with 1000/500 are pushing stockish power. Cornering grip has nothing to do with engine power.
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Old 11-24-2017, 09:04 AM
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Originally Posted by themonkeyman
A fair amount of people running 245s with 1000/500 are pushing stockish power. Cornering grip has nothing to do with engine power.
They would be faster on 225s...except maybe on a slalom course.

If it didnt have anything to do with people would run 275s up, they aren't.
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Old 11-24-2017, 10:15 AM
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Originally Posted by Savington
You cannot use F/R rate ratio to do anything except make yourself look bad, dude. 700/400 and 1100/500 have vastly different ratios but they both work for different reasons. The suspension is different front to rear and the rates reflect that.



We're going to go in circles until you stop posting bad info in the Race Prep section here. With 600/450 and Koni Yellows, no offense, you simply can't comprehend how bad your setup is compared to the average spring/shock package discussed in this section. You don't have the frame of reference to understand the shortcomings in your setup and how to address them.

It's not a knock against you, I'm sure you mean well, but it would be like me walking into a kitchen with professional chefs and telling them how much salt to use. They're going to be polite the first few times, but if I keep doing it they're eventually going to tell me to **** off, and they probably should.
I don't give a lot of "cats".....this post got one.
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Old 11-25-2017, 11:54 AM
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Originally Posted by Savington
You cannot use F/R rate ratio to do anything except make yourself look bad, dude. 700/400 and 1100/500 have vastly different ratios but they both work for different reasons. The suspension is different front to rear and the rates reflect that.
I struggled with this when you recommended I move from 850/500's to 1000/500. Emilio further advised I jump up to the 1.250" RB Sway Bar. I could not help but think it would under steer like a pig. I was wrong.



Originally Posted by Savington
We're going to go in circles until you stop posting bad info in the Race Prep section here. With 600/450 and Koni Yellows, no offense, you simply can't comprehend how bad your setup is compared to the average spring/shock package discussed in this section. You don't have the frame of reference to understand the shortcomings in your setup and how to address them.

It's not a knock against you, I'm sure you mean well, but it would be like me walking into a kitchen with professional chefs and telling them how much salt to use. They're going to be polite the first few times, but if I keep doing it they're eventually going to tell me to **** off, and they probably should.
Respecting the sources of the above recommendations and knowing all they have accomplished I disregarded my struggles with the logic of it all and took the leap of faith. VERY happy I did.

The moral of the story for those that surf these forums. We are fortunate enough to have a handful of well accomplished drivers with 1000's of track hours. They openly share and recommend setup info that most other racers would keep close to the vest. It would be wise to follow those recommendations and fine tune from there. It will save you TONS of development time and in some cases you may never get there on your own.

Last edited by k24madness; 11-29-2017 at 11:39 AM.
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Old 12-19-2017, 01:47 PM
  #57  
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A big thanks for all the suggestions! I left the rear springs at 450 and went to 750 as suggested by Savington. Also moved RB 1.125 sway bar to stiffest setting. What a great change- I was at Willow springs international this past weekend and with worn NT01 cut 4 seconds from my previous best 1:41 to 1:37. I know that s not a great time for the "big boys" but man was that fun!
Thanks again
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Old 12-19-2017, 01:54 PM
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37s are in the ballpark, WSIR is a hard track to go fast at. Glad the changes worked
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