Rams Eye The Track Guy

C7 Corvette Grand Sport... doing a burnout with a proper diff - Graham MacNeil  © I wrote a tech post comparing various open and limited slip diffs for a comparison and I found that a lot of people were asking questions. To simplify and make it easier to read, I decide to break them up for a future tech article about handling. Make sure to stay tuned for two posts on limited slip diffs this week!. WHY DO YOU EVEN NEED A DIFFERENTIAL? A differential's job is to allow two wheels on the same axle (or two axles in a 4WD drivetrain) to spin at different speeds so a car could smoothly go around a corner. Why do the wheels need to spin at different speeds? Each wheel on a car has to travel a different path to reach the end of the turn. You can see that for yourself every time you drive on snow covered roads or muddy trails. Four different tracks by four wheels/tires on one car going around a turn - Rams Eye The Track Guy  © If you take a turn, you'll see that each whe...

730 hp Mustang Saleen 302 Black Label - Saleen © Most people who track their cars quickly come to recognize one of the biggest enemies of speed; heat. Heat affects tires, brakes, fluids, the engine, everything. One area that gets more than its fair share of heat is the engine bay. The most efficient gasoline/petrol engines struggle to exceed 35% efficiency - meaning that more than 65% of the energy in the fuel that is burnt inside the engine is not converted into motion or 'useful energy'. Most of the non-useful energy left over is turned into heat. That means that your average hot hatch making 200 hp could easily produce around 300 kW (400 hp) of heat as a byproduct of making 200 hp. If you're having trouble wrapping your head around that number, that's enough power to heat a large home improvement store. In Canada. Some of that heat goes out the exhaust (thankfully) but a lot of it has to be dealt with in the engine bay through your radiator, and oil cooler i...

A couple of weeks ago, I posted my first impressions of Michelin's PSS vs Firestone Firehawk Indy 500 tires. I've run PSS's for several years on the Boss, but I'm trying the Indy 500's for the first time. In short, I was worried about the narrower tires (I was running 285/35/18 PSS but could only find the Indy 500 in 275/35/18) and tread squirm, but I was happy with them up to that point just driving on the street. I had the chance to drive on them for three track days now. So what were they like? After my first session, they made an impression that basically persisted for the rest of track sessions on them. Phenomenal, unmatched value. Now, if value is something that stands out above all else, it typically means the compromise between qualities you want and those you don't is less than ideal, but the value is attractive. This is no different. I'll start with the bad, which really boil down to two: ultimate grip and grip longevity. Grip is noticeably l...

I've been a huge fan of Michelin PSS tires and exclusively bought them for the Mustang over the last four years. So how did I end up here? This year, I was hugely interested in trying an "R-comp" tire. I had my eyes set on Bridgestone Potenza RE-71R's for two simple reasons: price and reputation. Although not a true "R-comp" tire on paper, it performs like one by the account of every single test and review I've read (down to wear rates...). They seem like they're easily the most affordable (from a big brand) R-comp tire and combine that with a reputation for having tons of grip, it was an easy top contender. I had my concerns, though. For one, I'm told and have read that they are an autox tire, not really designed for high speed, pressure, and temps associated with open track. For another, the Mustang is a heavy car (as far as track cars are concerned) being roughly 3,800 lb. (including driver), which will amplify the unwanted open track load...

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...