FAST1

Fast1, you seem to have a misconception about torque. No offense, but I know the basics about physics

Haven't we beaten this one to death yet?

Torque is something that you can measure on a dyno, and it's what provides the power to a car. HP is the work performed and is measured by formula.

The following is a factual statement that is very, very basic: the absolute maximum acceleration that any engine can deliver is at its peak torque. If you don't believe it, please check with any performance shop and they will quickly enlighten you.

A theoretical example. An engine produces its maximum torque of 300 lb/ft of torque between 4500 and 5500 RPM, and its maximum 350 HP at 8K RPM. If you believe that the theoretical car is accelerating faster at 8K RPM when the engine produces aprox 230 lb/ft of torque than at 5K when it produces 300 lb/ft of torque, than you are mistaken.

A question was asked earlier about shifting and why not shift as soon as you leave the maximum torque range. The answer depends upon gearing and where you will be in the torque curve after you shift. When shifting from first to second I will probably lose around 2K+ RPM. So if I shifted at 5500 RPM I'll be down around 3500 RPM or well below maximum torque. Depending upon the torque output at 3500 and 7K RPM, I would more than likely shift at around 7K RPM on this theoretical car to ensure that I will be at or near maximum torque after the completion of the shift.

That's why any serious racer at a drag strip will have a very clear understanding of his engine's torque curve, which will enable him to determine optimum shift points.

skaterbasist

Your changing a true statement into a false one.

"The absolute maximum acceleration that any engine can deliver is at its peak torque" is a somewhat true statement. But does this mean that after its peak torque, it completely quits on accelerating? Even after peak torque, acceleration will be there until a certain point, usually redline. If the power (HP) is there, the acceleration is there.

Quick question: Have you ever been to the drag strip? Have you tried your method of shifting? Because I have tried countless methods, and launching anywhere from 2500 RPMS (not anywhere near the maximum torque) and shifting at rev-up at 7000 rpms has yielded my best times and traps by far.

I can asure you with your technique, you would walk away embarrased from the times you would receive.

Like someone said, there's those who create theories online all the time, and those who actually try them.

Trust me, its track proven

PS. Good to know we're keeping the conversation clean. Lets keep it that way

.

muscarel

Oh, no, we're back to this again?

The reason you do not shift early is not only because the rpm's go down. Your car will be putting down less torque in 2nd gear at say 5k rpm than in 1st gear at 5k rpm. This is because of the transmission gearing. A numerically higher ratio means more torque to the ground BUT less MPH/1000 rpm. 2 identical cars with only their gearing changes: The one with the numerically higher ratio will put out more power but will be at a lower speed at redline. This is why people swap out their "gears" but if they go too aggressive than the car may be running at high rpm on the highway which is not desirable.

Please do a SEARCH on the net. All this information is there. The actual torque to the ground is not only what the car makes.

muscarel

6.8 second search:


http://www.allpar.com/eek/hp-vs-torque.html

Please read this, it explains power "to the ground" related to transmission gears and engine rpm.

skaterbasist

Who me?

I obviously know the torque isnt what makes a car go. Its power

.

muscarel

LOL!! No, not you. Fast1.

skaterbasist

Oh ok . Just wanted some clarification

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FAST1

The reason you do not shift early is not only because the rpm's go down. Your car will be putting down less torque in 2nd gear at say 5k rpm than in 1st gear at 5k rpm. This is because of the transmission gearing.

muscarel: You are right on target. I was looking at this as an engine only issue, but I should have considered power to the wheels, and that is determined by both engine torque and gearing which of course is always more favorable in the lower gears.

Mr_Ryte

Do you REALLY want an answer to that?

xvfasttrip

iTrader: (6)

I thought this thread is about estimating 0-60 on the G37... Anyway, I heard that the G37 produces less torque than the 335i and it is heavier. Doubt it could beat the 335i (but it's turboed).

FAST1

I believe that the consensus is low 5s for 0/60. The 335 has a nice flat torque curve that builds early and as you point out, and the G37 should be heavier. So it's very unlikely that the G37 will match the 335 in either the 0/60 or 1/4.

Moreover, I know two guys that have 335s and they both got their cars chipped. The 335's boost is relatively low, so this car begs to be chipped for maximum performance. Without the chip they were both running mid 13s. With the chip they are running high 12s. They are now competitive with much lighter C6s that have 400 HP.

muscarel

The 335s that have run high 12's "chipped" are running drag radials. I have not seen runs that fast without them. Drag radials would drop anyones time significantly.

That being said, I think the G37 will fall a bit short of the 335 in 0-60, 1/4 mile. The difference may become smaller as speeds increase though. Either way, if the G37 gains a coupe of tenths on the new G35 sedan, the difference will be small enough where any decision between the two would be based on other factors - looks, steering, handling, technilogy, price. I can't see someone buying a car because it runs 13.5 at 105 instead of another car that runs 13.7 at 103. If that is ALL you care about than neither of these cars is what you should be looking at.

I'm still considering both and will not make my final decision until I drive the G37.

inspector_yoo

My guess:

I'd say it's a little slower then the 335 in 0-60 but pretty similar in quarter mile. Why does it have to beat it? As long as it's up to par with it, I think it'd be fine.

I'm going to say 5.3 for auto, 5.2 for 6mt and quarter in 13.4. The 350z would be slightly faster.

I don't think because Evo/STi is estimated 0-60 around 4.9-5.2 and quarter mile around 13.1 or 13.2.

Our car's are geared more for the mid-end so I'd see our 0-60 a little slower, and quarter mile getting closer as the current Evo's/STi's.

wuyichao

the new bmw 335 coupe will destroy the new g37

however, these r 2 different price range cars

32k-38k with a 50k+ car

Hypnoz

Stop posting. Please. You don't know what you are talking about obviously.

It will not take a high rpm launch to get a 5.1 0-60. They are at a slightly better hp:weight ratio than the 07 Z, with more aggressive gearing and a flatter hp curve. High 4's are possible. Low 5's shouldnt be difficult at all.

I predict 13.1 @106 mph for 1/4 stats.