Rams Eye The Track Guy

In Parts 1 and 2 (Links: +Chevrolet 1LE & Grand Sport - How do they do it? Part 1 & Part 2), I concluded that grip is where Chevys excel and decided to try and figure out how they do that by looking at test data from Car and Driver's Lightning Lap features. The first thing that stood out to me when the 5th generation Camaro 1LE came out was the wider tires compared to the Mustang Track Pack of the time and even the Boss 302. The tires on the ZL1 and Z/28 stood out as much.. only on those, they stood out compared to just about anything that isn't a supercar. So I decided to start looking there; tire sizes.

To evaluate tire sizes, I calculated a weight-to-tire-section ratio for each car. Similar to the idea of power to weight ratio, where the number tells you how much weight each hp is burdened with, this tells you how much weight each mm of tire section is burdened with, so to speak. For example, a BMW M235i weighs 3,490 lb, as tested during the LL feature. It has 225/…

GM, in general, is starting to build a very strong reputation for chassis engineering but Chevrolets, in particular, have very strong performance on track these days, not just good handling feel and fun to drive attitude. In Part 1 (link: Chevrolet 1LE & Grand Sport - How do they do it? Part 1), I looked at different aspects and concluded that Chevys appear to have the advantage in grip. If you are still unsure that grip is where those cars excel, perhaps this number will change your mind: 1.11. That's how much lateral forces, measured in g, the 2017 Camaro SS 1LE generated in Turn 1 of Virginia International Raceway (VIR) during Car and Driver's Lightening Lap 2016 feature. 1.11 g also happens to tie the 2014 Viper TA, the 2014 Ferrari F12 Berlinetta, and even the 2016 Ferrari 488GTB. It gets more interesting too..


CarMax Lat-g2015 Chevy Corvette Z061.202017 Chevy Corvette Grand Sport1.192009 Mosler MT900S1.162015 Chevy Camaro Z/281.162015 Porsche 9181.162015 Nissan GT-R…

While testing a 2016 Focus RS for the comparison test (link: Ford Focus RS vs Subaru WRX STI vs Mitsubishi Evo X MR), I caught up to a 2016 Mustang Shelby GT350R and had a friendly head-to-head battle. Both cars were completely stock. The video doesn't capture just how good that car sounds. We had a chat afterwords and the owner was very cool about it. His rear tires were starting to look old and he told me it felt a little less grippy than he was used to, so they could have been heat cycled out. Our track is also short and technical, so high hp cars don't get much room to stretch their legs, robbing them of some of the advantage they'd have at a power and/or longer track. The Focus had the optional Michelin Pilot Sport Cup 2 tires. Check out the video below for a couple of laps.

All these cars have one common Achilles' heel. The engines sit entirely ahead of the front axles; a great family recipe for understeer. Then tell the front tires - already taxed from trying to keep that front engine sitting outside the wheelbase from going straight - to put some power down and you can only make matters worse. There are ways to mitigate the understeer with suspension tuning, of course, but the toughest part is power-on understeer. I don't want to get much into tires, but the thing to remember is that because tires have a certain "grip budget" - how much total grip they can hold/generate before they let go - when you get on the power in a car that sends power to the front wheels (FWD or AWD), you will rob some of the precious grip you were relying on to turn the car in order to put all or some power down. You'll run out of front lateral grip sooner than you would have otherwise, as a result. Worse yet, because of the unideal engine pla…

The new 2017 +Chevrolet Camaro ZL1, expected in showrooms by the end of this year, just beat the benchmark set by the last generation ZL1. With a lap time of 7:29.60, it is 11.67 faster faster than the last generation and even beat the last generation Z/28's time of 7:37.9 - which was done on Pirelli P Zero Trofeo R tires, far grippier than the Eagle F1 Supercar used on the ZL1. The car used is unchanged from the one you'll be able to buy, aside from the installation of data acquisition equipment, a roll hoop, and Sparco racing seats with six-point harnesses. Otherwise, the car was production stock and included the following:

6.2-liter supercharged LT4 V-8 making 650 horsepower and 650 lb-ft of torqueAll-new 10R90 10-speed automatic transmission (set to Track mode to enable Performance Algorithm Shift calibration, providing optimal gear selection without the need to manually select gears)FE4 Suspension with Magnetic Ride ControlPerformance Traction ManagementForged 20-in…

I'm finishing up a comparison post (link to introduction:Intro: Focus RS vs Golf R vs WRX STI vs Evo X) and, throughout the post, I realized that I have to go off topic a lot to talk about how each type of differential changes the way the car drives. As a result, I thought I'd write a separate post to go into more detail before I post the comparison to keep it more focused on the cars and avoid veering off topic too much.

By saying "Limited Slip Differentials" in the title, I am including torque vectoring diffs because, although current conventional terminology treats them differently, a torque vectoring differential is, in essence, a very sophisticated limited slip diff (LSD) that can be manipulated to actively help the car handle better. And while none of the cars in the comparison use open (without help from the brakes) or non-gear mechanical LSD’s, I’ll briefly discuss them so that the post is more inclusive. I’ll only focus on using power to help the handlin…