johnsopa

Not really sure how to explain this... so I have four track days with my old Radical SR4 now. Explaining it as a go kart from a handling perspective might be about right. Pretty high g forces with some aero. The Radical is definitely playful, not really twitchy, but very lively. And direct,of course. It seems like you can feel what's about to happen and anticipate the rear end getting a bit loose, etc.

I'm finding that although the Radical moves around a lot, the cornering speeds are higher, I'm on slicks, etc., it feels much more controllable and comfortable from a handling perspective than my GT4 and GT3.

This surprises me. I was expecting the Radical to be a handful but I'm finding it much easier to handle/correct/play with compared to the GT cars. Heck, even compared to my old SRF.

This seems surprising to me and I'm trying to understand why this is.

Any input would be appreciated.

Also any good reading suggestions for aero vs non aero handling?

fatbillybob

I'm very interested in the radicals. Everyone says they are easy to drive. They are popular in the US and even more popular in Europe and cross all forms of motorsport from auto-x to hill climb to trackdays and racing. My thinking is going from a 1g car to a 2.5G car is quite a leap. How do you tune your brain for that? I'm not sure I have the feel especially as I get near my 6th decade. I'm thinking I would think exactly as you post then look at my data and be disappointed that I was no where near the car's limit. I find it hard to believe running an aero car with that mechanical grip transition to having to trust the aero grip and go faster is easier than feeling what happens mechanically at the 1 g limit. But I have never done it so I have no clue.

ProCoach

I raced GT and Sedans for ten years but always knew I wanted a sports racing car. The older ones look better to my eye but if set up correctly and are on known tires, they are marvelous! An extension of your mind. You think, they DO.

The major reason I like them is the precision of the response to my inputs. Most people have to reduce/slow the amplitude and speed of their control inputs, especially steering in sports racing cars. They do that, and they start to “smooth out,” with the consequent lessening of drama both inside and outside of the car. It’s like a really nice scalpel after the butcher knife of a street car and the Hoffritz steak knife of a modern GT3 Cup, at least in my experience.

As as far as aero goes, it’s important to realize that below 60-70 mph, there’s not a whole lot going on, and almost all of the grip is mechanical, not aero. In GT cars, that threshold is higher and over a wider speed range. Between 70-110 mph, the purpose of aero adjustments is generally to help the balance of the car and offset (or enhance) the balance of mechanical grip alone. Above 110-115 mph, you begin to substantially increase loading and downforce, the key ingredient designed to keep the tires in contact with the road in cornering, transitions and braking.

The relationship of ALL of the aerodynamic add-ons (in addition to the basic shape of the car) is the most important thing.

ProCoach

I'm sure in your GT car you are at a greater than 1g sustained loading.

I found little issue (except lack of physical conditioning to hold my upper body, head and neck in place over longer runs) in going to a flat bottom sports racer with over 2G sustained capability. Having driven cars that are capable of generating 3G sustained (for a few laps before I ran out of breath), it's a linear curve, not an exponential one.

The car is a car. As long as the balance is good and breakaway characteristics are consistent and not too gnarly, the behavior is the same and very confidence inspiring. I think you'd like it.

The issue is that in the speeds where the aero component really comes into play, your brain is already rebelling anyway, because everything is coming at you so quickly and your *** is only an inch and a half or two off the deck.

So the first step is to develop enough familiarity so your brain isn't taken aback or scared anymore and things slow down in the cockpit and in your head. Then, you can incrementally become comfortable being slightly uncomfortable and carrying more speed (incrementally) into these high speed corners.

It's like developing braking skills, cornering skills or driving any car. You drive (or develop a plan to develop the skills to drive) a car to what IT'S limits are, not what you THINK it's limits are...

fatbillybob

I love this quote!

schao

I would offer two reasons for your surprise finding between tracking a sports racer vs a GT car: weight and center of gravity. The weight and center of gravity of your Radical is approximately 2x lower than a GT car, so you have more immediate and precise sensory feedback as well as those coming to you via driver controls (steering wheel, brakes and throttle). This greater communication to you from your Radical allows you to react more quickly and with more immediate response by your car. It's seemingly easy to drive at 90% of a sports racer's limits and still be substantially faster than a GT car. The remaining 5-10% will take seat time and lots of testing and development for the right chassis setup (ride height, rake, spring rates, damper settings, alignment, etc.).

As for aero, I agree with Peter's comments as his experience and expertise is well known. It really is about finding a balance between front and rear grip, and aero devices are just one set of tools to find that balance. A well aero-balanced car should not break away suddenly should you exceed its grip limits.

With all due respect to your driving skills, I suspect you are still meaningfully below the limits of your Radical. Try following a similar car driven by someone who is experienced with the capability of a sports racer. Remember that you are doing this for fun, so try to avoid putting too much pressure on yourself to get the last 5-10% out of the car's potential at your next event :-)

schao

You know I have a sports racer ready to go!

924RACR

We know Sherman sells good lightly-used cars! Hey Sherman!

ace37

Respectfully, do you drive the Radical right near or on the limit for half a lap or more at a time? I find in iRacing when jumping from a street car to a prototype that I tend to significantly underdrive the prototype. My initial perception was that they’re easy to drive, have great handling, and are super forgiving, but the reality is I underutilize the aero so it becomes a safety net - I’m underdriving the car. It created that impression for me in the virtual world, and that was the explanation in my case.

I don’t mean any disrespect at all - I just had a parallel perception.

johnsopa

I'm wondering how much the faster steering has to do with it. I'm thinking I might be too slow on the wheel when driving a street car but the faster ratio on the sports racer somewhat makes up for slow hands.

ProCoach

Most of the really good and effective GT car drivers (street cars) steer too much and too fast when they get into a purpose-built sports racer, but that fixes itself pretty quickly!

CharleyH

That is the best explanation I have seen!

Charley