Went go-karting last night (Arnolds in Oaks, Pa.), course has two smaller 180s, one larger 180, one large sweeper (mildly bumpy) and two smaller sweepers (one seemingly bumpier than the other). All the sweepers are no lift deals with the right entry line and no bad luck on hops over the bumps. The 180's were a bit more challenging to feel I "got it right".. The severe effect of getting sideways with the kart (takes a long time to get back the speed) made me think, "I have to drive this as a 'momentum car'"... but then I wondered to myself, "all right, hot shot, what the hell does that mean, exactly?"

So I thought I'd put it to you guys-- What makes a "momentum car" and what makes a car that is better handled by "power" driving (?)? What specific things do you do differently?

The things I concluded were things like
1) getting a little sideways to tighten up your line to get around someone on the inside of corner exit doesn't work. you lose too much speed
2) early apex + understeer on turn in is majorly bad.. (dive passes killed major speed, even when I held the position)

But when are these ever _good_ things if cars are evenly matched?

To restate the questions:
What makes a "momentum car"? (Power/traction ratio?)
Specifically what do you differently with a momentum car? (wider arcs, as opposed to autox style cornering?)
What makes these things bad for momentum cars, but good for "power cars"?

James, who doesn't like not really fully understanding the implications of a term he's heard used a lot..

 

This philosophical underpinnings of "momentum" are entirely relative.

Scott, who says the implication of what he just said is that he's heard entirely too much about momentum of late...it's only unimportant when you have a significant power advantage over your competition...in which case there is still no good reason for squandering it.

 

IMO, a momentum car is a car that's inherantly imbalanced (not handling, but overall), and because of this, there are several itterations of a "momentum" car. For one, you've got to keep the momentum going (lack of power), or you've got a lot of momentum to control, and not enough power to move all around effiecntly (too much weight.)

For example, a momentum car can be on that is very light, but underpowered (i.e., lotus elise), or a car that's slightly overweight and without enough power to be driven point shoot (i.e., my honda prelude). With a momentum car you've got to be as smooth as possible, and brake as little as possible; with a lighter (underpowered) car this is easy as you're not hurling around a one ton brick, but with something like my prelude it takes a little more caution since you're trying to both control the momentum you're driving (i.e. freight train), while trying to maintain as much of that momentum through every corner.

 

What RR98ITR said. It's all relative. Generally, a momentum car is one that doesn't have much power but handles fairly well, so being smooth is required to go fast. Obviously, being smooth in a powerful car also makes you go faster.

Examples of momentum cars:
Miata
1st gen RX-7
most old school British roadsters

They are all fast cars when driven well, despite lacking power. (once again, fast is relative, blah blah blah.)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MechE00 &raquo;</TD></TR><TR><TD CLASS="quote">What exactly do you do differently when driving a "momentum car"? </TD></TR></TABLE>
Finally learn how to drive.

 

technically all cars are momentum cars. in ultra competitive racing series like BTCC, you lift for a split second and you will not get it back.

generally speaking though, momentum refers to a car that is under powered in straight line acceleration. it is a car that feels extra slow when you lose speed for whatever reason and takes a while to build speed back up. another way to look at a momentum car is it handles much better than it accelerates. some cars have plenty of straight power but handles like crap, they are not momentum cars however, yet a good handling momentum car will kill them in lap times. corner speed is the key.

 

I'm suprised no one has mentioned this yet - but the single biggest thing that will allow you to manage and conserve your momentum properly is looking ahead. Thats it. Seems simple... at first...

 

Michael Schumacher was good in not wasting momentum in Barcelona in 1992 when his Benetton-Ford B192 only had 5th gear. IIRC, he finished 2nd or 3rd.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Outrun &raquo;</TD></TR><TR><TD CLASS="quote">Michael Schumacher was good in not wasting momentum in Barcelona in 1992 when his Benetton-Ford B192 only had 5th gear. IIRC, he finished 2nd or 3rd.</TD></TR></TABLE>

3rd place

I cant count on both hands how many times dan unkefer has told this story

 

Looking ahead is important no matter what car one drives. Slow car or fast. Actually it gets even more important the faster the car because the roads come up so fast it is unbelivable (Porsche 996 GT3-RS for example). Wheres cars at ITA lap times for example, relatively speaking, happens pretty slow. Indeed looking ahead sounds so simple, but takes constant reminders. Looking ahead is one of the key emphasis in the Evolution AutoX school and probably the biggest thing I learn from them.



Modified by GhettoRacer at 3:02 PM 8/29/2003

 

What do you do differently in a momentum car?

You try to carry as much speed as possible. You try not to brake too much or get off the line at all, since these momentum cars don't have enough speed to make up for it.

But, in a highly contested racing series where everyone has just about equal power, aren't those same things important, regardless of whether or not the car is considered a momentum car? Seems like a misnomer.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">What do you do differently in a momentum car?
You try to carry as much speed as possible. You try not to brake too much or get off the line at all, since these momentum cars don't have enough speed to make up for it.

But, in a highly contested racing series where everyone has just about equal power, aren't those same things important, regardless of whether or not the car is considered a momentum car? Seems like a misnomer.</TD></TR></TABLE>

It is not what you do differently in momentum car, but what it teaches you. What you learn from momentum cars is to maximize every thing - driving as efficiently as possible. That means in every aspects, deep threshold braking - but not overslow for turn in. Minimum sliding to carry more speed. Make full use of the track to carry as much speed as possible through the turns. Actually sometimes you take shorter paths if the speed you carry isn't enough to justify going the extra distance (I learn that from Berry Hartzel!). Make any small mistakes and it will instantly show in a momentum car, versus a moderately fast car, driver error gets masked sometimes. Does this make sense? It is same thing why I recommend to all of my students staying on street tires for as long as possible - any mistake will show. Once the skill is acquired on street tires, jump into R compound and be instantly WAY faster.

Everything you learn from a momentum car allows the driver to extract the performance out of any car.

 

if by "momentum car" you mean a car that handles better than it accelerates, then i would say the first thing is to change the line a bit to earlier apexes where you are late apexing to a straight. this gives a wider arc through the entire corner, and helps you keep your momentum. this is somewhat similar to moving the apex sooner (closer to geometric) as the turn gets faster / gearing gets taller.

in s-curves, switchbacks, slaloms, etc where the whole section is taken with balanced throttle, late apexing and "attacking the back" is still probably the best way.

 

I agree 100% that conserving momentum is important in every car. Some guys that learn track driving in hot cars think they are fast because they're times are respectable and they hit 140+ on the straights, but often they have really poor entry and mid corner speeds. (Ever been to a Viper Days event?)

If you learn how to go really fast in a low powered car, then add power....look out! You'll be the man.

 

these graphs short of illustrates some difference between a pretty well handling "momentum" civic vs. a powerful Porsche 996 Turbo that's softly sprung... you can easily see the raw acceleration power the Turbo has. although, the Civic holds it own in braking and cornering.

 

Momentum car= Every car I have ever driven and everything that I will ever be able to control

Power car= Mythical car with unlimited power that only exists in our simplistic dreams or in "Days of Thunder" where power is unlimited and getting to the front of the pack is just a matter of pushing harder on the pedal and gritting your teeth in close-ups.

Show me a driver in a non-momentum car and I'll show you a driver who needs to be doing a better job or a car that is ridiculously crippled by traction or handling issues and I still think the driver could likely use more refinement.

 

Don't use the brakes. A friend of mine did Keith Code's superbike school and they actually send participants out with instructions to NEVER use the brakes, starting as slow as they feel they need to and gradually increasing their speed. He said it was AMAZING how close to a "real" lap time the talented guys could get, without ever using the binders.

I saw the same thing at an enduro at Westwood (BC): The guy I was crewing for set his fastest lap after the pads had gone to the backing plates and the fluid had boiled out of one circuit. He just kept driving and got in a race with someone...

K

 

Most of what everyone has said is correct in my view.

Remember

Non momentum car - 917-30

Momentum cars - everything else

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MechE00 &raquo;</TD></TR><TR><TD CLASS="quote"> What specific things do you do differently?
</TD></TR></TABLE>

From what makes sense to me, in a low power car as someone already said you want to maximize your arc and keep it as wide as possible throughout a turn. In a high power car, you need to focus on being as straight as possible as early as possible coming out of a turn. The straighter you are, the more power you can put down. Being straighter earlier in the turn, you can put down more power earlier. Doing this usually involves late apexing.

 

Where does a car's drivetrain come into play?

I would think that getting on the throttle too early in an FR like the Miata or Hachi-Roku and inducing uber-low-speed oversteer would be absolutely lethal to lap times, maybe even more so than a little Civic-style push.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Knestis &raquo;</TD></TR><TR><TD CLASS="quote">Don't use the brakes. </TD></TR></TABLE>

I will re-iterate this. I was @ VIR full w/ my 95 hb w/ the d15b7 & was running the crap out of that engine. I hardly used my brakes & learned all about "momentum cars." I had a b20/vtec in the car previously @ this track... & going back to 60 hp & NO TQ was quite a learning experience.

Did I take any lines differently?? Yep... when you dont have power... you have to learn to keep a wider arc so you will keep your momentum. In a car w/ some power... you can take a tighter turn & go through the corner using your power to get you where you want to be.

 

Any of you guys remember the Intrepid GTP from the early 1990's? 1,800 lbs and a Katech Chevy V8 making over 720 hp . I was talking to Tommy Kendall in the paddock at Road Atlanta about his awsome car and he told me that "it handles great, but it needs more horsepower. I've really got to concentrate on carrying momentum because we are down at least 50 hp on the Nissans". Imagine my surprise because I was driving an ITC Civic with a minimum weight of 1,775 lbs and maybe 90 hp at the wheels...and they are both momentum cars! Another interesting fact; I was lapping Road Atl at 1:48 (with the good old "Dip") and he was doing about 1:10!

 

Just curious, when you refer to go-karts, are you talking about racing karts, i.e. used in competition karts (for those who know it, AllsportsGP-style), or are you talking about $5-for-an-hour beach go-karts next to the carpet slide karts? If the latter, just don't ever lift. Crofton Go-kart Raceway was an excellent place to learn that, not that it has any relation to any other type of vehicle, much less an actual car. Something I was considering in thinking about that though, while it was faster to just floor it the whole time, things got a little hairy in a few places. In trying to "keep the momentum going" in a "momentum" car, are you kind of doing that, like just throwing it around?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .RJ &raquo;</TD></TR><TR><TD CLASS="quote">I'm suprised no one has mentioned this yet - but the single biggest thing that will allow you to manage and conserve your momentum properly is looking ahead. Thats it. Seems simple... at first... </TD></TR></TABLE>

Hehe - I definitely noticed that. the only competitive event I have under my belt is the Rev It Up contest. It was easy to talk about looking ahead, but as soon as I got on the track I kept wanting to look at the apex of the current turn. Oh well, I guess it comes with time....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Fastom &raquo;</TD></TR><TR><TD CLASS="quote">Most of what everyone has said is correct in my view.

Remember

Non momentum car - 917-30

Momentum cars - everything else</TD></TR></TABLE>

Agreed! The 917 in all it's glorious forms was (and still is) a scary car indeed.