Under heavy acceleration,...
Under heavy acceleration, the GTO has only the required amount of weight transfer to the back, as shown. With the suspension set this way, corner exit feels more responsive. Since brake dive is almost entirely eliminated, corner entry has become a hassle-free scenario because you don't have to manage the previously excessive weight transfer.
All testing was done with Nitto NT01 tires. For the baseline, the aftermarket additions were tires and Hotchkis swaybars. Under modified, the car now benefits from a gamut of Lovells bushings from Kollar Racing and KW V3 coilover shocks.
Let's keep in mind that this road course is only 1.1 miles. To shave off one second on such a short course is very impressive. With the car now properly set up, our times were noticeably more consistent, as we have listed our best five laps as they came. When it was all said and done, the GTO was lapping the track nearly two seconds quicker than our baseline passes.
Best of all, I felt like a track star because the car responded better and was easier to control. Its handling limits were actually so hard to reach that I feel with more track time another second or two could be taken off. It was very satisfying to experience such a large improvement in both stability and cornering speed.
| Lap Times |
| Session |
Baseline |
Modified |
|
(Seconds) |
(Seconds) |
| 1. |
1:07:87 |
1:06:29 |
| 2. |
1:08:40 |
1:05:89 |
| 3. |
1:06:85 |
1:05:67 |
| 4. |
1:07:75 |
1:05:29 |
| 5. |
1:07:24 |
1:05:95 |
| AVERAGE |
1:07:62 |
1:05:81 |
Difference of 1:81 seconds per lap average
Difference of 1:56 seconds in best time comparison
Around the skidpad, our GTO...
Around the skidpad, our GTO went over 1.0 g-in a street car-eclipsing our previous record.
With the addition of our suspension components, the car certainly felt more controllable right on the edge of grip. That's very good news because it's what most drivers want. If a car can be taken to the edge of its grip and it still gives good feedback, it feels incredible. The combination of our dialed-in suspension and the brilliant R-compound NT01 tires was excellent.
Lateral grip is calculated by averaging our best pass clockwise and counterclockwise. This time around our goal was to exceed 1.0 g. Well how does 1.01 g clockwise and 1.05 g counterclockwise sound? That's an average of 1.03 g in a street car!
| 300-Foot Skidpad Testing |
| Pass |
Lateral Grip |
| Baseline |
0.965 g |
| Modified |
1.030 g |
Conclusion
With our new Lovells bushings from Kollar Racing ensuring us that there wasn't any unnecessary flex from the factory rubber parts, our KW V3 coilovers were able work precisely and we were able to tune the suspension more accurately. The end result is a GTO with greatly increased cornering speed potential that will require more seat time to fully exploit.
It goes to show that adding a good combination of suspension parts, tires, brakes, and tuning them accordingly will transform a street car into something completely wild and fun to drive. Best of all, taking the time to tune the settings for your new suspension will help you get the most enjoyment out of your new parts and the best results.
These are the final suspension items we will add to the car before we take the Goat out for a three-day jaunt on the track at Sebring International Raceway. Stay tuned to find out how to get involved in events similar to this one, and see how to get yourself and your car ready before you endure extended on-track sessions on a large open track.
Here is our alignment. The...
Here is our alignment. The camber is different on the lefthand side to counter for driver weight. It evened out with me in the car.
Some debate may be raised because everyone thinks differently when it comes to alignment. Our alignment suggestions came from three sources: Andy Kollar, Jay Chen, and members of LS1gto.com who are actually out there open-track racing their GTOs.
After talking with all three parties, the initial thought was to run as much negative camber as possible, as everyone boasted about how impactful an ultra-aggressive camber setup would be on the cornering. But an alignment such as this can chew up tires fast, so we backed off the camber and toe settings.
Alignment settings will be different for each car type, but our setup shows a good compromise for a street car that sees the track on the weekends.
Here's the difference between...
Here's the difference between negative and positive camber. For the cornering benefits, we went with approximately 2 degrees of negative camber. Most avid racers love to go with 3 degrees or more, but this car is also a street car so 2 degrees is used. The KW shock body is narrower than the factory struts and allow for camber adjustment. The factory struts don't allow for any camber adjustment. As a matter of fact, the tire-to-strut tolerances are so close from the factory that when the strut mount bushings collapse, like ours, the tire will rub the strut. We replaced our strut top mounts with Lovells polyurethane mounts, which won't collapse on us. Having excessive negative camber will wear tires irregularly on the street but help the tire bite-in during cornering. For the rear, we went with slightly less camber than the front, because the IRS naturally increases negative camber under load. The rear Lovells bushings provided by Kollar Racing allow us to adjust rear camber; the factory ones had no adjustment
This diagram shows the dramatic...
This diagram shows the dramatic differences between having a lot of positive or negative caster. Caster is the angle in which the steering pivot axis is tilted forward or rearward from 90-degrees vertical, as viewed from the side. Andy and everyone on the LS1gto site were keen on dialing in a lot of positive caster on our late-model GTO. Since Andy provided us with adjustable radius rod bushings, we were able to increase our positive caster to 9.5 degrees on both sides. Having this much caster not only increases straight-line stability, but also steering effort. This is something that should be kept in mind for older Pontiacs without power steering because it can make it difficult to steer. It's also important that both sides are equal-it will cause the car to track left or right if they are offset.
Toe settings affect three...
Toe settings affect three major areas of performance: tire wear, straight-line stability, and corner-entry handling characteristics. This is an area that can completely change the way a car handles, and at the same time, will eat through tires faster than you could imagine. Having excessive toe-in or toe-out will cause the tires to scrub because they are always turned relative to the direction of travel. Toe-in causes accelerated wear on the outboard edges of the tire, and toe-out wears the inboard edges. We have our GTO set to a very small amount of toe-out, it's actually within the factory alignment tolerances. Having toe-out will cause the inner wheel to steer in a tighter turn radius than the outer wheel. This makes the vehicle always want to enter a turn, rather then maintain a straight line of travel. Toe-out encourages the initiation of a turn, while toe-in discourages it.