RoadconeTuning

I've currently got a set of pedders springs sitting there waiting to go on the car because I read all over the interwebs that they supposedly make the car handle better. I've never heard whether it just increased the limits and kept the stock balance towards understeer or if they loosened up the rear because just loosening up the rear increased my corner speeds tremendously.

If someone can put it into words how do the combos i posted in the title compare to one another? stock being the epic understeer setup...

fwiw the car has 235/40R18 Michelin Pilot Sport PS2's on it on stock wheels. which is something like 7-8mph slower around a clover leaf i use vs my old 225/40R18 NT05/Conti2 setup.

Wangspeed

iTrader: (2)

The Pedders don't really increase performance at all, IMO. I've run stock, stock + hardcore, pedders + hardcore, and pedders + XXX. The change between stock and pedder springs was minimal. IMO, it is mostly cosmetic. The rear bar makes a bigger difference, though anything short of the XXX will still result in quite a bit of understeer. The other thing I really dislike about the Pedders is that they WILL cause you to bounce off the front bumpstops very hard under hard braking. And if you don't have Konis, it will suck even more. The Konis can help keep it from bouncing quite as much on them thanks to the extra rebound valving.

Quite honestly, I think rear bar, and Konis make a bigger positive difference than Pedders do. Personally, I would advise getting Konis before getting Pedders.

BLue NoTe

iTrader: (4)

I did the whole SC to TC conversion chassiswise, only thing I'm missing are the factory sway bars. So I've had the pedders with the sc (16.5:1) and now tc (14.8:1) steering rates. Stock sc setup was too soft and definitely understeered more than I wanted, the tail never rotated. Pedders addressed the excessive roll and did up my limits, the car became much more solid feeling which means everything to the driver, the feeling of confidence.

I also ran the ttr bar which sent the rear out on autocross runs but didn't do much on the street. The xxx bar took care of any mid corner understeer and even gives me power on oversteer exiting fast corners. I'm tempted by the konis but my setup now performs beautifully, Idk if they would only serve to harshen the ride

Ackermann

Well I did some runs with a borrowed g-meter before and after installing the Powell Hardcore bar on my TC sedan, so I can answer part of your question. Completely stock, including Conti tires, I saw a peak lateral acceleration of 1.13g. After installing the bar that went up to 1.22g, which is a good improvement.

Feelwise, the hardcore bar makes the car feel more neutral in hard driving. It doesn't make the car oversteer, but the rear tires are definitely doing a little more work. I can't really think of a good way to describe it, but it just feels better and more balanced.

I also have a set of Pedders waiting to be installed, so I can't answer that half of the comparison, but I would expect them to make a much smaller difference. My understanding is they have a faster progressive rate, so under hard cornering they should limit body roll and weight transfer to the outside a little, but I'm not sure what the F/R balance of them is compared to stock.

Wangspeed

iTrader: (2)

Peak lateral numbers are kind of useless...

RoadconeTuning

i was gonna say i've see 1.12 on my RPD and routinely saw 1.05-1.09 completely stock on Ceasars head downhill thru the hairpins... I dont think i ever got as high of a reading with my NT05's on the front but corner speeds were deff higher.

Now i'm torn between the Hardcore and XXX bars... my previous car was a mustang that was a bit oversteer happy and prior to that I had a Fiero (mid 80's mid engined pontiac for those who dont know) so i'm somewhat used to off throttle over steer.

Wangspeed

iTrader: (2)

You will never have on throttle oversteer, so IMO, if you are comfortable with off throttle or braking oversteer, the XXX is the way to go. Again, this is dependent on the driver and conditions.

And really, I think with the XXX bar, Konis, and Pedders, the lift throttle oversteer is by no means fast. In fact, it is still a little slower than I like, but it's very easily controllable, even when wet. YMMV.

scottherbert

I completely agree with Wangspeed! I have Eibach ProKit springs, Konis, and an XXX bar and I love the combination. (I used to have a Hardcore bar.)

Scott Herbert

07SSYellow

iTrader: (7)

^^ i Trust Scotts opinion very much! and Wangspeeds these guys nkow there stuff when it comes to racing the SS/TC's!

395 plus

iTrader: (1)

I was at the track with another cobalt SS/sc he is running e85 and putting down 300whp and was running on pedders with Hardcore bar stock shocks. I have the TC springs/shocks and XXX bar, about 255whp our tires were about the same and going through the Carousel I was running faster speeds (about 79mph) than he was. This was on Road America. I have tried the pedders and went back to the TC springs ride is better and like Wangspeed says you dont hit the bumpstops.

Wangspeed

iTrader: (2)

One other thing I did to help my suspension out was that I'm running linear rate bump stops. They're a little more predictable when you get on them, but you'll still bounce if you hit the brakes too abruptly. Car sits too low in the front with Pedders, given their stock like spring rate.

I got these and bored them out for my Konis, the 58mm, 200lb/in ones:

Fat Cat Motorsports - High-performance bump stops - all makes and models

The next time I take them apart, I may try the longer 76mm bumpstops at a softer 120lb/in rate, but that will depend on the possible upcoming suspension options John is working on

Powell Race Parts

iTrader: (3)

good post

Powell Race Parts

iTrader: (3)

another good post. On street performance tires you really want the softest possible spring rates but keep off the bump stops. The rising rate on Pedders is different the spring is shorter. The travel with stock TC springs would be advantageous. If you go to stickier tires like Wangspeed the game changes. Most of the street tires and R tires make you want to improve damping rates as well especially in rebound. But put R100 on and the game changes completely, you need more spring and hardly notice damping rates the tires stick so well.

Then the springs need to be stiffer etc once you drive on R100 or R80 slicks, but you also need an HHR ps motor at that point the stock steering motor wont deal withit all very well.