2017 STU Discussion!
Mar 20, 2017, 08:33 AM
#31
I installed stiffer rear springs on Saturday. Previously 650/700, now 650/850. Hotchkiss RSB on full stiff. The car is feels substantially better with the stiffer springs in the rear. Now I wish I had made the change earlier.
Changing springs is easy enough that I'll probably try a 700/900 setup next. A local nationals-level autocrosser who previously owned an Evo suggested I try 700/1000, which seems a bit too high. I'm curious enough that I may give it a shot. 1000 lb/in in the rear would require a revalve, but I may just have them revalved with 900 lb/in springs in mind. I certainly can't imagine going higher than 1000 lb/in rears on street tires.
Changing springs is easy enough that I'll probably try a 700/900 setup next. A local nationals-level autocrosser who previously owned an Evo suggested I try 700/1000, which seems a bit too high. I'm curious enough that I may give it a shot. 1000 lb/in in the rear would require a revalve, but I may just have them revalved with 900 lb/in springs in mind. I certainly can't imagine going higher than 1000 lb/in rears on street tires.
If you don't want to go up in rear spring rate, you could always try a bigger RSB
When I was on 700/900 (using RJones' JRZ RS Pros), it felt pretty decent until we got the car on a surface with lots of grip (Crows Landing). The car would just push all over the place with those rates, going to 700/1000 helped a lot but you definitely notice a penalty in ride quality and things might get more "interesting" at bumpy lots
Mar 20, 2017, 08:39 AM
#32
Evolved Member
When I was on 700/900 (using RJones' JRZ RS Pros), it felt pretty decent until we got the car on a surface with lots of grip (Crows Landing). The car would just push all over the place with those rates, going to 700/1000 helped a lot but you definitely notice a penalty in ride quality and things might get more "interesting" at bumpy lots
Mar 20, 2017, 08:47 AM
#34
The car didn't ride badly on 700/900, but going up in rear rate did make it worse (obviously).
Y'all are crazy running those rates on street tires. Raise the car to fix your front Roll Center and don't be so scare of a little roll.
I already did.....
Next project will probably be to see if I can reduce the spring rate all around but still have the car handle similarly to how it is now. You're welcome to take some runs in it if there's a TnT course at the Crows Pro
Mar 20, 2017, 08:55 AM
#35
Evolved Member
Believe it or not, but they do work! I was lucky enough to run 8760 Penske shocks on my 2G and even with pretty high rates, ride was pretty good (both street on all season tires and racing with Hoosiers) compared to anyone running much less with Koni yellows for example. To put some perspective to it: Koni's with 550/450 were way worse than Penske's with 800/650 for example.
Mar 20, 2017, 11:04 AM
#36
Believe it or not, but they do work! I was lucky enough to run 8760 Penske shocks on my 2G and even with pretty high rates, ride was pretty good (both street on all season tires and racing with Hoosiers) compared to anyone running much less with Koni yellows for example. To put some perspective to it: Koni's with 550/450 were way worse than Penske's with 800/650 for example.
Mar 20, 2017, 11:08 AM
#37
Evolved Member
Mar 20, 2017, 03:09 PM
#38
I haven't noticed any down sides yet, aside from a marginally worse ride quality. The car is no longer my DD so I can afford that, though.
Mar 20, 2017, 04:10 PM
#39
Side note Construct, Could you do me a favor and take a measurement of the control arm angle from like a phone app (both sides to account for ground level), and measure ground to fender gap on both sides?
My constant issue with big spring rates is tire rate vs wheel rate. Rear is a bit more tolerant to big springs because the M.R. is low and overall weight unsprang weight is ~50% less than front. Tires make terrible shocks, and bad roll centers combined with that give dangerous hops when accelerating out of corners.
I run less spring than you with 295 hoosiers and don't feel any spring change would help roll. Tires still squish
My constant issue with big spring rates is tire rate vs wheel rate. Rear is a bit more tolerant to big springs because the M.R. is low and overall weight unsprang weight is ~50% less than front. Tires make terrible shocks, and bad roll centers combined with that give dangerous hops when accelerating out of corners.
I run less spring than you with 295 hoosiers and don't feel any spring change would help roll. Tires still squish
Mar 21, 2017, 05:01 AM
#41
Evolved Member
Are we connected on Facebook?
Mar 27, 2017, 04:56 AM
#44
My first event in STU trim is in the books. Rather interesting weekend lol. The Northeast got hit with a late winter storm and the only place that aligns my car was essentially inaccessible. I whipped out the toe plates and went to town figuring it's better than nothing. Once all done I noticed my camber plates weren't similar side to side but I chalked it up to the difference being at the knuckle. Side note, I have two girls (2yrs and 9month) so my wrench time is essentially rushed and very limited.
The event was with NNJR (home region) which is super competitive, weather was good, 60's and overcast and I had a co-driver.
The car:
2014 Evo X GSR
Suspension/Wheels:
FA500 coilover 12k/16k
Ciro FSB Brackets on full stiff
Whiteline RSB and Links on the middle setting
18x10.5 et22 wheels with 275/35/18 Rival S tires (illegal tires, just killing them off)
GT Spec Front Tower Brace
Power:
Open Source STU legal Tune
AEM Boost and Wideband gauges
AMS High Flow Pipe
Invidia Single Catback
Cobb Intake and Inlet pipe
Long story short, fastest STU car out of 6, I pax'ed 15th out of 108 and Raw timed top 10. The car was changing every run and once I left the event I realized something was wrong. In order to drive straight I had to turn the wheel about 20 degrees to the left and hold it there. Once I got home I jacked the car up and both locking collars on the coilovers were completely loose. The amount of play from thread slop was INSANE. My alignment was insanely off, driver at -4.2, passenger at -2.2 (its just how the car settled with the slop.) Toe I didn't even bother measuring and just took it apart and tightened up the locking collars. The next day I went to the shop and got it aligned.
Here is what I rolled in on.
Front:
Camber -4.4, -3.5
Toe: .06, -.26
Caster: didn't even bother lol
Rear:
Camber -1.5, -1.4
Toe: .01, 0.07
So this was best case scenario after I tightened everything up, at the event it was way worse than this.
Current setting:
Front
Camber: -3.8, -3.8
Caster: 4.2, 4.1
Toe: -.06, -.06
Rear:
Camber: -1.7, -1.7
Toe: 0.00
Thrust 0.00
I can't believe my co-driver and I didn't hear any noises or notice there was a huge problem with the car. 3 very experienced people drove the car and nobody said anything.
Video:
Me and my codriver side by side:
His view:
First run the car was a disaster due to cold tires and dirty lot lol.
I only have one quick questions, when we rode together and got REALLY aggressive the car would begin pogoing/binding in the rear, almost hopping. This only happened in 2 sections of the course. You can see my codriver experienced it a lot more as he was much more aggressive and really threw the car around. It even happened to him in the opening slalom. It is impossible to replicate on the street as the grip level needed is simply going to get you arrested or hurt. Is the general thought here to reduce rebound and let the suspension work? Base on the results vs setup...I am VERY excited for this car. It was shocking how good it was.
The event was with NNJR (home region) which is super competitive, weather was good, 60's and overcast and I had a co-driver.
The car:
2014 Evo X GSR
Suspension/Wheels:
FA500 coilover 12k/16k
Ciro FSB Brackets on full stiff
Whiteline RSB and Links on the middle setting
18x10.5 et22 wheels with 275/35/18 Rival S tires (illegal tires, just killing them off)
GT Spec Front Tower Brace
Power:
Open Source STU legal Tune
AEM Boost and Wideband gauges
AMS High Flow Pipe
Invidia Single Catback
Cobb Intake and Inlet pipe
Long story short, fastest STU car out of 6, I pax'ed 15th out of 108 and Raw timed top 10. The car was changing every run and once I left the event I realized something was wrong. In order to drive straight I had to turn the wheel about 20 degrees to the left and hold it there. Once I got home I jacked the car up and both locking collars on the coilovers were completely loose. The amount of play from thread slop was INSANE. My alignment was insanely off, driver at -4.2, passenger at -2.2 (its just how the car settled with the slop.) Toe I didn't even bother measuring and just took it apart and tightened up the locking collars. The next day I went to the shop and got it aligned.
Here is what I rolled in on.
Front:
Camber -4.4, -3.5
Toe: .06, -.26
Caster: didn't even bother lol
Rear:
Camber -1.5, -1.4
Toe: .01, 0.07
So this was best case scenario after I tightened everything up, at the event it was way worse than this.
Current setting:
Front
Camber: -3.8, -3.8
Caster: 4.2, 4.1
Toe: -.06, -.06
Rear:
Camber: -1.7, -1.7
Toe: 0.00
Thrust 0.00
I can't believe my co-driver and I didn't hear any noises or notice there was a huge problem with the car. 3 very experienced people drove the car and nobody said anything.
Video:
Me and my codriver side by side:
His view:
First run the car was a disaster due to cold tires and dirty lot lol.
I only have one quick questions, when we rode together and got REALLY aggressive the car would begin pogoing/binding in the rear, almost hopping. This only happened in 2 sections of the course. You can see my codriver experienced it a lot more as he was much more aggressive and really threw the car around. It even happened to him in the opening slalom. It is impossible to replicate on the street as the grip level needed is simply going to get you arrested or hurt. Is the general thought here to reduce rebound and let the suspension work? Base on the results vs setup...I am VERY excited for this car. It was shocking how good it was.
Last edited by laloosh; Mar 27, 2017 at 05:15 AM.
Mar 27, 2017, 06:53 AM
#45
EvoM Guru
iTrader: (1)
Pogoing on hard corner exit acceleration?