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What makes a Spec car faster (and slower)?
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TOPIC: What makes a Spec car faster (and slower)?

Re: What makes a Spec car faster (and slower)? 13 years, 9 months ago #8387

Big Dog wrote:
You cheating bastards, studying data and learning about trail braking. That amounts like DRIVER COACHING and, clearly, is against the spirit of our series - Low Cost, Slow Speed, Equal Racing.

Philosophically you guys have just got to stop this or you will tear our series apart. If you want to race like that, go to some other series because NO HERE.

Big Dog



Jim,
That post is filled with sarcasm, but that fact may be lost on many who do not know you like we know you.

Eric is making quite clear what most of us having raced in the series for a long time know. Speed comes from driver skill and that skill comes from corner entry. Anyone can mash on gas and accelerate out of a corner. That is especially easy with 130ish hp at the rear wheels.

Speed is made on corner entry and learning balance the chassis to maintain speed. Eric's data chart clearly show that. There have been many times I have come up to pass mid pack or even back of the pack runners. I never can pass them on power. If we exit a corner at the same speed I have no hope of passing another 944 for miles around. However once we get to a brake zone is when things change. The fast guys know how to carry a bit more speed at corner entry while still maintaining good exit speed. As such they can either pass at corner entry and seemingly "fly by" or pass on the next straight not by using hp, but exiting the corner 5 mph faster. That 5mph corner exit speed gain helps two fold. 1) means the car is already moving 5 mph faster and second is that it probably puts you high rev range in the same gear. So accelerating from 5000 rpm vs 4500 rpm gives you more hp to wheels when both cars get on the gas. So it can appear that the fast guy is accelrating faster. In fact he is, but that is not down to the car, but corner exit speed.

Notice the much higher average speed of the red car line in the first 4-5 turns. That is killer for the competition and all about drivers skill and chassis balance.

Oh yeah... Chassis balance. You can try to trail brake deep and carry cornering speed, but if you do not take the time to balance the chassis you will never reach your full speed potential. You could be driving the wheels off the car, but if it is not well balanced you will still be slow. These cars have alot of room for adjustment when it comes to free stuff like camber, toe, sway bar positions, ride height.

Your car will never be fast if you can't adjust for understeer/oversteer at corner entry, mid corner and corner exit. Even all the data in world won't help if you can't feel what that car is doing in 3 main parts of a corner.
Joe Paluch
944 Spec #94 Gina Marie Paper Designs
Arizona Regional 944 Spec Director, National Rules Coordinator
2006 Az Champion - 944 Spec Racer Since 2002
Last Edit: 13 years, 9 months ago by joepaluch.

Re: What makes a Spec car faster (and slower)? 13 years, 9 months ago #8388

  • cbuzzetti
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Excellant points Joe!!!

Some of the drivers do not adjust their chassis at all. Simply because they don't know how or don't want to make it worse.

It is important to make one adjustment per session (on a practice day) to see whow the car reacts. Even if it is only tire pressure. 1 lb of tire pressure does make a difference in these cars and it will teach you to chase the perfect setup to help you go faster. All of this is more important than HP.

The Honorable Mr. Foxx needs to hace a sarcastic font developed just for him
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Re: What makes a Spec car faster (and slower)? 13 years, 9 months ago #8389

Another interesting aspect of the velocity graph that is illustrative of Joe's point is that the red car is consistently faster in and faster out of the corners but the rate of acceleration is virtually identical for all three cars. I would bet that if you put up the graph for acceleration/braking g's you would see the same thing.
Steve Marlow
944 Spec #47x
NASA Certified Instructor
NASA AZ Licensing Director
2012 AZ Region 944 Spec Champion

Re: What makes a Spec car faster (and slower)? 13 years, 9 months ago #8390

This is true.

All cars on this graph made within 2 HP on the dyno. Guess which car was carrying a passenger? Pretty hard to tell! The other cars were a bit heavier to start, but the car represented by the red line was about still 150 lbs heavier than the other two.

I edited my post from this morning - it should be more readable now, than when I put it in over a bowl of cereal at 6 this morning!
Eric Kuhns

National Director Emeritus

2007, & 2008 National Champion
2011, 2012 2nd
Last Edit: 13 years, 9 months ago by Sterling Doc.

Re: What makes a Spec car faster (and slower)? 13 years, 9 months ago #8392

  • rlofgren
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As for matching traqmate HP figures to dyno figures: does traqmate adjust for elevation(i.e. Miller)? If you look at the altitude/weather adjustment, my car was actually only making 134HP/1.16 SAE adjustment equals 115 real HP at that altitude. My traqmate says i am making 140HP at the same time.
944-SPEC #30 Norcal 2010 Champion
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Re: What makes a Spec car faster (and slower)? 13 years, 9 months ago #8394

I'm not sure if it adjusts for elevation. It certainly does not adjust for changes in elevation (i.e. going up or down hill).
Eric Kuhns

National Director Emeritus

2007, & 2008 National Champion
2011, 2012 2nd
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