onefastviking

You are not allowed to do that this year ! - Even if I have to fix your car myself !
You should have won ST2, hell you had it covered if the motor hadn't gone.
Besides, I want you to then run in GTS so I can see how we compare.

mark kibort

I would love to go, never been to mid ohio and want to go there and road atlanta before I die!

So, yes, we are respectable adults. please give me the respect to tell me what the heck we disagree on anyway. you have made a few posts, one or two about me running in V8supercar, and the other:
Also, I really like Fey's answer, it is by far the most realistic real world performance answer to the question of when to shift and why taking all factors into account, not just some dyno graph and gear chart. Am I the only one that see's this ? I doubt it so speak up if you do.

I just was talking about Fey's comment as well and fine tuning it to not be misinterpreted. (the 2% part)

what do you disagree with, as far as what I have said or posted?

Im not even clear on what you said about Fey's comments because it seems you are discounting graphs or charts to calculate shift points in general.

As I said to Dave, I absolutely agree that short shifting in certain areas of a track is more than warranted. going through s's, conditions, middle of turns, etc. I am strictly talking about straight line, acceleration.
Draw a straight line from redline to post shift point on the hp curve. if you cant get it straight and it angles down, shift at redline. pretty simple, right?

mark kibort

Here is about the only gear box where Fey's idea will come in to play. (I know there are more, but here is one that fits the bill)

if you had a close ration Cup car gear box, with .8 rpm result post shift, there are gears where you would want to shift early. 6300rpm to 5000rpm for example. but with the stock gear box of 70% RPM post shift, clearly, you see it pays to shift later, to redlie and then some. 6500 to 4600RPM.

Now, here is the discussion. 2% is 5 hp in this range and is pretty darn close.
with shift times a factor, its less than a rounding error if you get it in this range anyway.
with the curves below, VR, you would shift at 6500rpm way way down the back side of the HP curve, to get to the Buddy Fey advised 2% difference range. how would you do that, and not prove yorurself wrong with your advice? If you shifted early as we do with this car for longevity, you end up with 275hp shifting down to 245hp a 10% difference! redlining gets you to a perfect arc, 250hp shift, to 250hp post shift (near 0%) and that maximizes hp, even though the HP plows down to 250rwhp at 6500rpm!! (not shown here, as redline is 6500 rpm on this motor)

Veloce Raptor

Mark, are you STILL arguing this, tilting at windmills?

Yikes. Let it go.

quickxotica

Nobody stop him, he's on a Blaze!

winders

VR,

Check this out:

http://www.physicsforums.com/showthread.php?t=301773

What do want to bet that "zanick" who signs with the initials "mk" is you know who?

What does "zanick" do there? **** everyone off?? Yep....

Scott

Veloce Raptor

Good guess .

http://www.youtube.com/user/zanick

mark kibort

I will as soon as you admit, shifting 300rpm before redline because , in most cases, is only in the RPM range of "noise". you have already shown and said a preference to not drive an engine on the downward slope of a hp curve, and rather shifting as it is rising. as you can see by the graph, your preferecnce would cause one of your students a race, if that was the way you were teaching. Hey, we are all here to learn. If there was some truth to your logic, i would use it in a heart beat. so far, the only thing scientific word you have used in your LOGIC, is the word, "noise" to describe your theory.

Until then..............


and Scott, you read my challenge to you. find me out of those two cars, big torque vs small torque, equal HP , where will the higher torque car have any advantage. you made quite a point to try and show that I was incorrect. all Im asking you to do is politely respond back with an answer.
Do you still think big engine torque has an advange over lower engine torque???

Veloce Raptor

Yes, of course, Mark, you are the ONLY one here who can possibly be correct.

Oy vey. If I weren't laughing so hard when your post barrages show up.....

Again, thanks for the entertainment, Mark. Bless your heart!

winders

Mark,

As usual, you use limited and specific examples as proof for your general arguments. Exceptions are not the rule.

Horsepower is torque measured over a period of time. You need torque at the wheels to accelerate. Yes, if you have engines with the same horsepower but different torque, you can use RPMs to get the same torque to the ground.

If you don't have optimal gearing, the engine with the more area under the torque curve is going to have an advantage. If you have to start accelerating at lower RPMs, the engine with the more area under the torque curve is going to have an advantage.

Look here:

http://www.team-integra.net/forum/bl...er-curves.html

The bottom line is that the engine with the more area under the torque curve is going to be easier to drive and more forgiving when the revs drop.

Scott

mark kibort

Thank you Scott. Yes, that was my point. never said i was the rule and most of the time, i was saying it was the exception. as this graph set proves, a high strung BMW has more advantage anywhere than a "torquey" 928 of the same power. certainly , NOT the rule as you say. certainly the exception. BUT, i bring up the exception to make the next point regarding close ratio gear boxes, which then allow both cars (torquey V8 and high strung 911) to operate at near max HP and get the same acceleration. is it easier to drive the torquier engine? probably , because you are shifting less. But, if you only need a little more HP to couteract the extra shifts you might be making.

This is why I have always responded with the exception to prove that the torquey engine desire is not always the rule. It depends. Just as shift points depend on the shape of the HP curve and the gear ration spacing.

As I started to say many years ago, the HP curve is just easier to work with vs the torque curves, and gear ratios to find shift points and compare performance.

now to your link to the integra curves. Yep, its much easier to drive the torquier car on the street, but on the race track you want the greater average power. however there is such a difference in high hp vs loss of lower end torque, it looks near the same for even racing due to the trade offs. after all, at 25% rpm drop the gains are offset by the losses. 6000rpm to 8000rpm would be the operating range.

I think we both understand each other now. wheew!!!

2BWise

VR, the first response in the link you posted is pure gold.

Here's his opening. Couldn't have said it better myself.

mark kibort

As a side note Scott, you talk about me taking a situation of high torque engines vs low torque engines and showing an example of how they perform the same anywhere on the track, as being unique or the "exception" . As I said, you are right. In fact, everything VR talks about in wanting a big Torquey V8 is correct. I drive a 928 for that reason too! BUT the arguement has never been about that, its been about the exception, and the relationship about HP and engine torque. (not rear wheel torque). Now, you cant have these arguements always your way, right?? This is why when the next topic, of shift points came up, I came up with the same kind of general rule, to shift at Red Line. Its generally the rule, not the exception. The exception is some choked up V8 who's intake air cant get out of its own way, and HP curves that fall like rocks. Those can be shifted at below redline for good reason. sure, others as well, but they are not the rule, the exception.

Anyway, on to the Track!

Veloce Raptor

Perfect!!

winders

2BWise,

I posted the link....not that it matters. But here something from another poster in that thread that Mark still needs to understand:

Gnosis wrote:

Zanick, the matter hasn’t been reduced to a philosophical debate in the least. Your supposition concerning horsepower and torque is quite simply backwards. Torque isn’t a factor of horsepower rather; horsepower is a derivative of torque. You must first produce torque if you are to “calculate” a “horsepower rating” for the engine.

Horsepower is an intangible quantity that cannot be measured directly, but more importantly, horsepower isn’t a “force”. Horsepower is simply a rating of how much work can be performed over time and distance. It is “calculated” per the torque measured since torque CAN be measured directly in ft lbs. For instance, when an engine is stated as having 200 HP, it is merely a rating of how much work can be performed at a given RPM per the engine’s available torque.

The dyno measures torque by applying a known braking force to the dyno’s rotating drum. When the vehicle’s drive wheels accelerate the dyno’s drum under this braking force up to a given RPM in a given time, it reveals the torque being applied by the vehicle’s drive wheels, as it would require a given torque to have accomplished this rate of drum acceleration in the time recorded.

Force produced in a Combustion Engine

Consider where the combustion engine actually produces its force. It is per the optimized A/F ratio ignited per each power-stroke, as the piston and its connecting rod are forced downward by the expanding hot gases in the cylinder with the other end of the connecting rod applying its force to the crankshaft in a manner that provides leverage to rotate the crankshaft and produce crankshaft torque. So, torque is the accelerative component, not horsepower.

You need to get horsepower out of your head and acknowledge the actual source of the vehicle’s acceleration; that being torque. Horsepower is only a rating of how much work can potentially be performed at a given RPM per the available torque.

Horsepower is a “rating” of potential work that can be accomplished, but it is NOT an actual force

For instance, my workouts had me moving approx 30,000 pounds of free weights a distance of 3 feet in an hour’s time. This can be given a horsepower rating HOWEVER, that horsepower rating does not imply an actual force used. It merely specifies a total of 30,000 pounds was moved 3 feet over a span of one hour (a given weight moved a given distance over time). In fact, some weight movement was several hundred pounds per rep while things like curls were more around the 95 to 115 pounds. Again, horsepower doesn’t specify a given force rather; it implies a given amount of work that can potentially be accomplished.

Hopefully this will provide the insight you need to resolve your confusion associated with horsepower. Unfortunately, those who tend to adore horsepower and have long confused its meaning have a most difficult time relinquishing their love for its mighty-sounding namesake, when it’s actually “torque” that should be held in highest accord.

I demonstrated the example below back in my mini-bike building days. It demonstrates the significance of an engine’s torque.

Firsthand Example:

I used a 1.5 HP lawnmower engine to power a mini-bike and I geared it to yield a top-speed of 35 MPH while on flat ground with my body weight of 140 pounds. However, while riding at 35 MPH on flat ground, I came to one of the steepest streets in my neighborhood. My mini-bike steadily lost speed and would not make it all the way up to the top of the steep hill. When I hit the hill, the engine was at its upper rev range therefore producing its 1.5 HP, so why could it achieve 35 MPH on flat ground, but not make it to the top of the steep hill?

Answer: The engine lacked sufficient torque to accomplish the climbing of the steep incline. The incline imposed additional loading on the crankshaft, so the engine’s crankshaft steadily lost RPM. As its crankshaft slowed, less A/F mixtures were ignited per second as a result, so less over all energy was provided per second, which further slowed my ascent. It must be realized that “IF” the engine’s torque were sufficient to climb the steep hill in the first place, the engine would have never slowed down. A 2.5 HP combustion engine remedied the issue, as it produced greater torque and even had enough extra torque to start out from a dead stop up the steep hill. From a dead stop (engine just above idle), it couldn’t be the extra HP yielding the more than adequate acceleration up the hill; it was a direct result of the extra torque provided by the 2.5 HP engine.

Point: A given task requires a given minimal torque to accomplish the task. If less torque is produced, then it makes no difference what the “horsepower rating” is, the task will not be achievable.

Torque is king...the extra RPMs lower torque engines need so a transmission can multiply their torque are not always available.

Scott