Everything about Fat Cat Motorsport Suspension

[duracellttu]

It's been a while since I've been on forums and have been through a few different spring setups since this original post. I think I have finally found an OEM+ street setup that is comfortable and sporty. Through trial and error and I tested many different setups. Below is a brief overview of that journey...

1) 350/336 F (7" linear springs) & 700/675 R (5" linear springs) -- TMS Front (medium setting) & Rear (soft setting) Sway Bars --> bad oscillations over bumps and the car would not settle. I believe this was because of the linear springs in the rear. Per the Ride Harmony spreadsheet, 1.07 "flat ride", 73.8% FRC.
2) 350/336 F (7" linear springs) & 500 R (TCK barrel springs) -- TMS Front (medium setting) & OEM Rear Sway Bars --> oscillations from previous setup were gone. Per the Ride Harmony spreadsheet, 0.92 "pitched", 77.8% FRC.
3) 400 F (Eibach 170-60-0070, 6.69" linear spring) & 600 R (TCK barrel spring) -- TMS Front (medium setting) & OEM Rear Sway Bars --> Very stiff ride. Per the Ride Harmony spreadsheet, 0.93 "pitched", 74.4% FRC.
4) 336 F (Swift Z60-178-060, 7" linear spring) & 600 R (TCK barrel spring) -- TMS Front (medium setting) & OEM Rear Sway Bars --> Very sporty on the street, while maintaining comfort on rough roads. Per the Ride Harmony spreadsheet, 1.02 "flat ride", 75.6% FRC.

For the latest setup, I still need more seat time. Initially impressions were great and I am really enjoying this setup so far. Personally, 600# rears are as stiff as I'd like to go, to maintain my comfort level. If I want to aim towards an OE level "flat ride" it would require making the front springs much softer. The stock suspension has a 1.18 "flat ride" ratio, which would require 250# fronts and 600# rears. I might try that in the future, but for now I'm happy.

[bigjae46]

Thanks for posting and looking forward to hearing what you end up with. Other than going flat ride, have you messed around with FRC on your setup (e.g. front bar setting or size) trying to get better turn in? Want to learn from your testing.

I started with 400lb springs on the flat ride journey. I loved it at MSR Houston - a bumpy track. The problem is I'd scrape my splitter frequently which means a loss of downforce. Then I swapped in a 450lb spring on the left front which did might have helped scraping a little bit. 500 lb front springs all but eliminated scraping but added understeer.

I've added rear downforce but the understeer only happens at 60mph or less. The front end is great at higher speeds which tells me it is a suspension limitation rather than an aero imbalance.

I haven't made any other changes except for a rebound adjustment. I might make another small adjustment on the front to see if that helps.

[ethan]

I'm writing this more for me to remember things but I also want to document my journey on deciding what direction I want to go.

Thanks for posting and looking forward to hearing what you end up with. Other than going flat ride, have you messed around with FRC on your setup (e.g. front bar setting or size) trying to get better turn in? Want to learn from your testing.

[bigjae46]

I'm writing this more for me to remember things but I also want to document my journey on deciding what direction I want to go.

My suspension is getting worn out. I can feel the suspension bottom out, especially when I messed up and ran over a sausage curb at COTA. It was kind of brutal and alarming...never really had that before. And I've definitely ran over those curbs before. My dampers are almost 13 years old and have seen over 50k miles across 2 cars. I have zero doubt its time.

Right now, I have TC Kline doubles with 500/700lb springs, stock front bar, no rear bar. Ride heights are (bottom of fender to ground) 26" in the front and 25.25 and 25.375 in the rear. Weight as "raced" is 2866 (LF 791, RF 691, LR 728, and RR 655).

I've talked to Cronenberged and messaged thegenius46m to get there experience with FCM. Both were a tremendous help...thanks!

Here's the dilemna. I'm mostly happy with the TCKs. My car is far more comfortable than almost every street car that I instruct in. The results of kind of applying flat ride have been great. Won NASA TT3 despite being closer to a TT4 car. I run consistent 1:41s at MSR Houston on RRs and NT01s, not many cars under 400whp are running those times on those tires. I'd be well in the 1:39s with a Hoosier.

My only complaint is low speed understeer - under 60 mph. It turns in but it feels rather dull. Trail braking deeper has helped (also helps with lap times) but over time I have learned to drive around it. This doesn't really hurt me that much at MSR Houston (my home track - bumpy), I think this understeer has a significant impact at the tracks in Fort Worth which have a newer and smoother surface. I'm not nearly as competitive on those smooth tracks.

I am also very skeptical of vendors. I've heard a lot of bullshit from some of the more popular vendors. FCM seems different in a good way. Maybe a little eccentric? But to be better you have to be a little different. If do go FCM, no doubt it will be the Stage 3 Elite. I guess it comes out to $5500-ish all said and done. Its about $1000 more than MCS and $3000 more than replacing my TCK dampers. If I can get the suspension right out of the box then $5500-ish sounds cheap when you factor in the time and expense to get the suspension dialed in.

It will be a couple of months. I want to get most of the weight reduction done before I do the consult. I hope to make a decision this fall and post here which direction I go and why.

[usdmej]

Yeah not worth the $$$. Has anyone here documented the weight savings with Recaro PP ABE?

pretty much the same weight savings as running a pole position. they're within a pound of each other

[Thoglan]

Yeah not worth the $$$. Has anyone here documented the weight savings with Recaro PP ABE?

IIRC PP ABE's are 2 or 3kg lighter than nogaros.

[EthanolTurbo]

I saved 59 lbs total, going from heated/leather/power stock seats, to CFRP nogaros/leather/heated/manual e46 sliders-- just under 30 lbs per seat saved.

... CF Nogaros would have saved another ~10 lbs per seat, but... $$$.

Yeah not worth the $$$. Has anyone here documented the weight savings with Recaro PP ABE?

[Obioban]

much closer to 30 pounds per side if you run a pole position. Nogaros are relatively heavy as far as fixed back seats go, i wouldnt be surprised if the leather versions put you only in the 20lbs/side savings range

I saved 59 lbs total, going from heated/leather/power stock seats, to CFRP nogaros/leather/heated/manual e46 sliders-- just under 30 lbs per seat saved.

... CF Nogaros would have saved another ~10 lbs per seat, but... $$$.

[usdmej]

This is a big reason I'm taking my Sportster CS out of the M3 and putting them in the M5... definitely more suited to that car. I believe Cobra Nogaros or Recaro PP will net about 40 lbs per side savings IIRC.

much closer to 30 pounds per side if you run a pole position. Nogaros are relatively heavy as far as fixed back seats go, i wouldnt be surprised if the leather versions put you only in the 20lbs/side savings range

[Obioban]

Oh I see - so hardware like springs, swaybars, etc?

No— like blowoff valves internal to the shocks.

[cobra]

It’s cheaper if you just do their revalve service. It gets pricier when they start adding hardware.

Oh I see - so hardware like springs, swaybars, etc?

[Obioban]

Aren't they just non-adjustable H&R's (Bilstein's) with a tune? So $1400 for parts and $3600 for a tune?

It’s cheaper if you just do their revalve service. It gets pricier when they start adding hardware.

[bigjae46]

Aren't they just non-adjustable H&R's (Bilstein's) with a tune? So $1400 for parts and $3600 for a tune?

And most people spend a lot more than $3600 at the track getting their suspension right.


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[cobra]

That’s relatively cheap when you consider the cost to setup the suspension.

Track fees, fuel, tires, brakes, wear and tear, etc.


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Aren't they just non-adjustable H&R's (Bilstein's) with a tune? So $1400 for parts and $3600 for a tune?

[EthanolTurbo]

you're looking at ~10 pounds weight savings per side assuming BK and OE hardware

closer to ~20 pounds weight savings per side if you go with the Sparco SPX (pricy, but probably the best reclining seat on the market at the moment)

This is a big reason I'm taking my Sportster CS out of the M3 and putting them in the M5... definitely more suited to that car. I believe Cobra Nogaros or Recaro PP will net about 40 lbs per side savings IIRC.