Subaru WRX handles poorly after mods

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dwillms

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Hello,

The basic premise of my message is that I have a '95 Subaru WRX STi that I have modded to about 440 HP, and after doing a St.2 weight reduction and full racing suspension, my car seems to handle terribly now compared to what it used to.

Now for the extended version!

First car purchased was the aformentioned '95 WRX, I have used it for the majority of races/series so far. It always was a great handling car, which is why I continue to drive it despite owning 400R, RUF CTR, BP RX-7, etc.

Now I had basically done most everything to the car, clutch/flywheel/transmission, LSD, carbon driveshaft, port polish/engine balance, St.2 turbo. As I said, it was around 440 HP, and handled well. After getting about $30 K, I spent it on full race suspension and St.1+2 weight reduction.

After this point, the car has MASSIVE understeer, I am basically snowplowing into every corner. I saved more money and bought a VCD. I added weight ballast to equal the weight reduction, as to eliminate variables.

Now, even after playing with toe and VCD, even going back to standard suspension, I just can't seem to get the car anywhere near how I remembered it used to drive. I'm to the point of removing all mods and going back to a stock car, and trying to "rebuild" it from the ground-up.

I ran a test lap at Apricot Hill to see if maybe I was just crazy, with my settings the best I could get them. I ran a 1:44 with my 312 HP N/A Honda S2000, and an identical 1:44 with my WRX, which should have easily won with equal weight and 130 extra HP.

Sorry for the length, I just have had a lot of fun with the car, and don't have the money to start over in rebuilding another one.

Thanks,
-Dustin
 
did you try loosening up the front suspension, tightening up the rear
add a wing for more front downforce?

distribute more torque to the rear wheels... maybe about 25% front

and for drastic measures driver assist... weigh it more heavily on preventing understeer
 
Loosened(softened) front suspension, played with rear toe, and fiddled with VCD to change torque distribution. Could only get it to handle a little better. Just couldn't figure out why such a drastic difference(at least it seems).

-Dustin
 
perhaps brake more before the corners 👍

seriously tho... run with out the mods at a track, and then run with the mods at a track and compare your corner entry speeds.

just cause you have 440 hp doesnt make the car turn any better... but it does make it take longer to slow down.
 
brake earlier. I learned this very quickly with my Elise. A mere 10hp increase made a noticeable difference in my braking distances. This is one thing that the game is going to teach you over time. Too much power isn't always a good thing. The 20hp increase I currently have on the Elise is probably the most I'll ever do to it. It can already keep up the Mercedes SLR McLaren in the corners. However, i completely lose it on the straights. A bit of transmission tweaking should help fix that issue for me.

Anyways, try to torque from the front wheels and put it towards the rear - i forget which part allows that. Also try dropping about 50hp and getting a stage 3 weight reduction. The lower weight will help your braking distance and alleviate most of the lost horse power. The torque bias towards the rear wheels will help reduce the understeer inherent in 4wd cars.

It could also be that you're not getting enough traction to the front wheels. Try softer tires up front maybe?

edit: I see that you have the vcd already. Anyways, try losing some power. With All wheel drive and high hp, you'll get more and more front wheel drive characteristics. There's not much that can be done about that.
 
I had similar problems with my STi spec C. After the first trubo upgrade, the handling took a dive for the worst. I haven't had time to change much, but I will certainly look into tuning and figuring what went wrong. The car is no longer a joy to drive, even if you have to brake earleir.
 
eliseracer
I had similar problems with my STi spec C. After the first trubo upgrade, the handling took a dive for the worst. I haven't had time to change much, but I will certainly look into tuning and figuring what went wrong. The car is no longer a joy to drive, even if you have to brake earleir.
Click to expand...


I guess me 3 my Lan Evo II 92' is understeering from hell, i have racing suspension... Ill try lightening the front and hardening the rear, for just springs? what about shocks? i ony got a 1.5 way diff.. just got the game yesterday. Any other suggestions cuz i did retry to soften it and it continues to dip a lot.
 
my c-spec handles like a charm

i noticed the best improvement when i added a wing for more downforce.

for a smooth track with lots of turns..

tcd is set to 1 (o/u): 7/10
lowest rideheight
left the shock bound and rebound
left the toe and camber
spring rates (f/r): 11.1/12.8
stabalizers (f/r) 5/6

breaks (f/r): 10/10

downforce max (for now)

limited slip (f/r)
initial: 10/10
acc: 20/40
dec:10:20

vcd:30

racing medium tires
 
Just like RoxxorJoorSoxxo said, get rid of the LSD. The Subies don't seem to like anything but the standard LSD (although I haven't messed around with the fully customizable one yet). I noticed the older GC Imprezas rotate alot better and get power-on oversteer fairly easily, especially when running in the 400hp range. Also the default settings of the 'Original' type suspension kit from the tuners seem to work well with these cars. You can try increasing the camber in the front a little and decreasing camber in the rear. Remember these are AWD cars, so they are less tossable than other FR and MR platforms and need to be driven accordingly.
 
The power I'm finding isn't the problem at all, as the car seemed to handle fine(as I remember it) when I had 440 HP, it was adding a St. 2 weight reduction and full-race suspension that seemed to cause the problem. Regardless, I've got understeer to fix. Now, for something I've been trying to understand:

Can somebody please explain this to me, which I read in the Tuning Guide: To fix understeer, soften front and/or stiffen rear suspension. Why is this true? It seems to me to be the exact opposite, but I can't understand the example listed and am having a hard time wrapping my head around it.

It seems to me if my front(outside) tire has too much weight in a corner, and slips causing understeer, stiffening the front suspension to help more weight transfer to the inside tire would be the solution. Or you could soften the rear suspension to allow more weight to transfer to the outside tire.

I'm sure I am very confused somehow in this, but common sense dictates that stiffer spring rates lead to better weight transfer and better handling, so this why I do not understand.

If anybody has a good diagram/simple explanation for why the softer end of a car produces more grip, I would love to hear it. Thanks again,

-Dustin
 
definetly try changing your driving style, with lighter weight increase u'll be going a bit faster then before.

im no tuner and still trying to learn a bit, but in regard to the spec c, it handles great imo, after i bought it i purchased:
trip-clutch, SM flywheel, roll cage, stage 3 weight reduction, driveshaft, all engine upgrades (port polish, etc.), no LSD, no tranny (stock seems fairly good for 400hp), Suspension: Original (the one after Full Custom) and a Racing Intercooler. no turbo upgrades whatsoever, left all the tuning stock just to play around, and right now it seems to handle really well.

however im used to understeering with my low-powered prelude, so don't take my word for it =P try it.
 
Try powering down the Spec C. Stay away from the heavy staged turbo upgrades and instead play around with gear ratios. If you are getting heavy understeer, the basic suspension tune is to soften up the front so it can grip better. Also, don't max out both of your stabilizers. Too much horizontal stiffness will turn your car into a brick. One more tip is to get a brake balance controller and lighten the power on the back wheels. This will give you a little more turn-in when braking into corners.

Take your driving aids off too.

Check out M-Spec's guide that is stickied on this forum.

I bought a Spec C for rally use and found when I powered it up to 400+ hp there was just way too much braking needed to counter the understeer. Now in the 300s, it works great on street courses too with a pretty stiff front and somewhat looser rear end - it can haul on the flat streets with a lower overall height and still turn in quite like a rally car to take advantage of those narrow corners.
 
dwillms
Can somebody please explain this to me, which I read in the Tuning Guide: To fix understeer, soften front and/or stiffen rear suspension. Why is this true? It seems to me to be the exact opposite, but I can't understand the example listed and am having a hard time wrapping my head around it.
Click to expand...

if the front is softer, it allows more weight to transfer towards the front. essentially the car is "leaning" more on the front tires so they have more grip since they are supporting more weight of the car relatively to the rear.


dwillms
It seems to me if my front(outside) tire has too much weight in a corner, and slips causing understeer, stiffening the front suspension to help more weight transfer to the inside tire would be the solution. Or you could soften the rear suspension to allow more weight to transfer to the outside tire.
Click to expand...

right... so theres a balance that you need to achieve.
 
think physics...

what is turning your car? its the friction between the road and the tires right?

to get the force of friction, you multiply the coeficient of friction with the normal force. the normal force is the tangential force between the rubber and the road.

more weight means more force of friction which means the tires grip better.
 
think physics..

what is turning your car? its the friction between the road and the tires right?

to get the force of friction, you multiply the coeficient of friction with the normal force. the normal force is the tangential force between the rubber and the road.

more weight means more force of friction which means the tires grip better.
 
With an understanding of how tires produce tractive force and why, let's define understeer as when we are putting too much download over the front tires and oversteer as too much load over the rear tires.
Click to expand...

if the front is softer, it allows more weight to transfer towards the front. essentially the car is "leaning" more on the front tires so they have more grip since they are supporting more weight of the car relatively to the rear.
Click to expand...

Now, correct me if I am wrong, but if understeer is when TOO MUCH weight is on the front tires, wouldn't softening the front suspension and allowing more weight to transfer towards the front make things worse instead of better? I would think that stiffening the front/softening the rear and having more weight on the rear of the car would be what would fix the problem, up until you have oversteer.

-Dustin
 
dwillms
Now, correct me if I am wrong, but if understeer is when TOO MUCH weight is on the front tires, wouldn't softening the front suspension and allowing more weight to transfer towards the front make things worse instead of better? I would think that stiffening the front/softening the rear and having more weight on the rear of the car would be what would fix the problem, up until you have oversteer.

-Dustin
Click to expand...

well i am no expert, try both and see what happens

to me this may be talking about the difference between kinetic friction and static friction. static friction coeficients are larger than kinetic. what makes you go is the static friction between the tires and the road. thats why we have antilock breaks

so maybe the balance to achieve is between not enough weight on the front and too much weight. if too much weight, static friction is overpowered by the car's forward momentum? the car starts sliding and kinetic friciton takes over which is weaker...thats why we understeer.

i guess this opens a whole nother can of worms... maybe your breaks arent set up properly? either they are too strong and the wheels are locking up, or they are too weak .. yea.. maybe limited slip is not allowing enough slip so your tires are sliding during the turn? maybe your front is too stable and does not allow enough body roll... maybe its just your driving technique who knows.

someone else please comment lol
 
I have a fully modded Spec-C with Stage5 turbo and Original Suspension from the tuner village. I spent an hour on it yesterday to tune it for The Ring and with the setup bellow I got a time of 6:48. The following setup has also worked beautifully on every other track with only one minor change, dropping it down to the lowest ride heigh offered by the original suspension, raising my shocks 1 or 2 kg on each end and the shocks by one click.

Suspension: F/R

Springs: 5.2/6.3
Ride Heigh: 86/86
Shocks: 6/7
Camber: 2.0/1.5
Stabs: 4/6

Brakes: F/R 10/12

Transmission: 12 on the auto setting

LSDs: F/R

Initial: 5/15
Accel: 30/60
Decel: 15/35

VCD: F/R 20%/80%

Downforce: F/R 20/30

Driving Aids: ALL OFF


That Spec-C is a friggin go-kart now. My fav car in my garage to drive at the moment, next to my M3 GTR of course :sly:
 
Thanks for the settings. I will try them out to see what kind of results I will get.

I am going to start a new post re: my other question about stiffening front suspension to correct understeer.

-Dustin
 
dwillms
Thanks for the settings. I will try them out to see what kind of results I will get.

I am going to start a new post re: my other question about stiffening front suspension to correct understeer.

-Dustin
Click to expand...

Thats incorrect. To correct understeer with the front suspension you have to soften it not stiffen it. Softening the suspension adds more grip, to an extent. Stiffening it to much will just create more understeer.
 
PinkusCorollus
Thats incorrect. To correct understeer with the front suspension you have to soften it not stiffen it. Softening the suspension adds more grip, to an extent. Stiffening it to much will just create more understeer.
Click to expand...

Woops... That was me posting that on my friends new GTPLanet account. Hehehe.
 
You can solve this easily. On my subarus I have full mods on them and i just modify the gear ratios and brakes. If your car is handling bad, just put the brake controller level up a few levels. For instance i have my '02 WRX STi with 520 hp. I just modified the gear ratio to 25 and tweeked the final and 6th gear ratio. As for the brakes, I put my brake controller level to 5-7 (depending how confident you are) and my cars seem to handle quite fine.

NOTE: on my full race cars my brake controller level is 7-8
(hp and drivetrain dependent)
while my street cars have a brake controller level of 5-6
(again hp and drivetrain dependent)
 
i have the spec c also and i think that my settings might be something to check out, as they are much different from yours. ill give your settings a try also, but here is my suspension:

8.3 spring
92 height
5 bound
7 rebound
3.7 camber
0
7 stabilizer

if you let off the gas in a turn the car rotates really well, and then when you get back on the gas the car stabalizes and/or understeers as awd cars do. i do not have an LSD installed and my power distrib is 10/90. brakes i have at 7f, 12r. no ballast weight applied. no driving aids, and full downforce front and rear. i only have 377 hp coming from this car right now, but its more than enough to beat turbo and boxer cups.
 
haha sry didnt realized that you were talking about whatever a Spec-C is, i though you were talking about a subie wrx sti Spec-C.
 

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