M758

Bill makes a good point about racing.


In a club racing eviroment my car can be a momentum car or a power car depending on which car I am trying to pass or is trying to pass me. All depends on who has the hp and who does not.

So car I need to us my momentum to pass and others I actually want loose momentum to Since I know I can out power them.

Example... Racing a spec miata (105 rwhp & 2100 lbs) Goal is slow the car as my 944-spec (131 rwhp & 2600 lbs) can out drag a spec miata all day.

Example 2 ... Racing a spec Mini cooper S (150 whp & 2700 lbs) Goal is to carry speed around the car since we can't ever out power them. So to pass I need to "get a run" an whip by.

These are two classes of cars that we in Az often race with and run very similar lap times to.

richard glickel

Are all cars "momentum cars"? Don't know.

This much I do know, different cars will permit or demand different driving techniques. For example, I know there are lines I can drive with my 968 (M030) that I cannot (dare not) attempt with my '87 Carrera-3.6L/300 h.p. (even with its full coil over suspension, big reds, etc.).

My line with the 968 (better handling car) is much tighter than with the 911 (more powerful car). I also seem to track out with greater ease (and wider) in the 968. Now it could be that the 968 is just better "sorted" at this point - at least from a handling standpoint. It could be the new Pirelli Corsa p-zero tires (terrific grip) on 18" wheels. I know that I can get away with things in the 968 that I wouldn't be able to pull off in the 911. That is to say that I don't believe I could hop out of the 968, jump into the 911 and drive in exactly the same fashion with the same result.

The 968's ABS certainly makes a difference. Trailbraking is accomplished with a degree of certitude, i.e., less "pucker" factor than in the non-ABS 911.

I like 'em both. If I do get to PCA club racing later this year, it will be in the 968. The car won't be competitive in the class (it will have to be a prepared rather than stock class), still it will continue to be great fun "momentum car" to drive.

Richard
'87 Carrera-3.6L widebody
'93 968 Coupe M030

Wormhole

Just to comment on the Big Bend Line. I believe skip Barber has recorded consistently the fastest line trough big bend is with both wheels on the pavement while trail braking the whole section. Something to do with the pavement having more grip there. Now with our type cars it’s probably a different story.

Bob Rouleau

IMHO every car is a momentum car. Sadly some people with big HP think that they can go slower in the corners and then boot it down the straights -often in front of me, dammit

My GT2 with around 500 HP is a momentum car and when I forget, I go out in a Boxster to remind myself and prevent being power-corrupted.

Rgds.

87turbo911

I kind of thought that a "momentum" car is one with (relatively) low-HP/weight but (relatively) balanced so well that it can take higher speeds in a corner than other cars within its class.

Or something like that.

DGaunt

A momentum car is any car with less HP than mine. an HP car is the rest.

Seriously, having lots of HP early in your DE/racing career seem to encourage slower entries and reliance on the hP to make it up on exit.

If you start with a low powered car, and learn to brake and carry speed, if you ever get into a car with b*lls you will fly.

I agree with the others above. a good driver will be faster than a sloppy one in the faster car. check what I drive....I MAY be biased...chuckle...but i know what I see out there.

richard glickel

Dave,

Yep. That's why I got into the 968. I'm hoping that your theory is correct, since at present, I don't feel that I can drive my 911 with the same good progress I seem to be experiencing with the 968. It may just be a function of getting the 911 to handle the way that I would like it to. Most, if not all, of the "right pieces" are there - so perhaps it's only a matter of time. Part of the problem is that, after refurbishing the 911 (show quality paint work, widebody conversion with factory 930 front fenders and steel flares, etc.), I just didn't have the heart to drive the car on the track any more.

Anyway, I REALLY like the way the 968 handles on the track, and it's plenty fast enough for my (minimal) driving skills.

Richard
'87 Carrera-3.6L widebody
'93 968 Coupe M030

DGaunt

Richard, I remember there was a great deal of debate in our region some years ago about taking a pristine, expensive car on the track. The consensus then among those who has such cars, was that it made more sense to leave the pretty car in the garage on DE days and acquire a track car. This is perhaps even more true today as more insurance companies write no-track-for-any-reason clauses in their policies.

Now, RE: 968...I know the car is fast and easier to drive fast than a 911, but don't you miss that heart in the throat feeling at the turn-in?

MetalSolid

There are momentum cars and there are "momentum cars", as in all cars are momentum cars because, as we all know, you always want to go thru a corner as quickly as possible, maximizing acceleration, braking and grip. So, a car with massive amounts for HP, F1 quality brakes but low grip will be faster if not driven the classic "momentum" style, relying more on it's best attributes which are deceleration and acceleration - more point and shoot. Alternatively, a car with low HP, poor brakes and great grip would also rely most on it's bests attributes, which in this case is grip. Most track cars fall in the gray area between "momentum" and "point and shoot" cars, as they are usually pretty well sorted.

87turbo911

That's pretty much what I was trying to drive at in my earlier post in this thread. The ones that are fastest when taking a turn in "classic momentum style" are what I'd call momentum cars.

Of course, this assumes that the driver is consistently good. Being a relative newbie, I think I'd just be slow regardless of style (or lack thereof).

Brian P

How about this: a momentum car is one that catches you in the turns, and a HP car is one that catches you on the straights.

If the same car catches you on both the turns and the straights...

87turbo911

I would call it "Cool."

38D

My old car (a '71 914/2.0 with all of ~95hp) was a true momentum car. And yes, it was very frustrating catching high hp cars in the turns, only to have them blast away down the straight (and trust me, even a 944 NA would crush this car in a straight line). I whole hearted agree that everyone should have to drive a really low power car when they first start...it really teaches you to carry speed into the corner. A friend of mine bought my old 914 (aptly named Slow Hite), and it has literally changed his driving. Before, he was in the Yellow run group driving a modified 951...he was one of the faster car in his run group. At one event, his car broke, and I let him drive my 914 (a different one with a 3.2 ). He literally could almost not drive the car. He realized that his 951 was "saving him" nearly every time. After that, he bought my old 914, and has progressed to be one of the better drivers in Black (with me being the best ).

pig4bill

I think rather than momentum cars there are momentum tracks. I assume Jack O is talking about Big Willow. At first glance it looks like a power track because the speeds are so high. I was talking about it to a racer that's run it many times and he considers it a momentum track. There are few corners that you accelerate hard out of through the gears. By contrast, screw up your line through turn 1(100+ mph) or turn 8(130+ mph) by just a little bit and your lap is ruined.

Then you look just across the way to the Streets of Willow, a tight, technical, many-cornered track. People wonder why the Vipers do so well on it. It's because you're constantly powering out of tight turns. The speeds don't get high enough so that big aero is as effective as on Big Willow, but big torque does well there.

JCP911S

Another 2 cents. one factor is how the car takes power out of a turn. Typically you pretty much want to be at full throttle at the apex... or even earlier.

Sum of lateral accelleration (cornering speed) and forward accelleration (throttle) on the tires can't exceed 100%, so you have to trade the two off.

If the car has enough HP to bust the rear tire loose exiting the turn, you need to change line and take a later apex... classic slow in fast out... trading cornering force for forward accelleration...

If the car will take full throttle either because it is less powerful or had alot of grip, then you maximize exit speed by increasing entry/cornering speed... momentum car...