HP Torque

RiCharlie

Hi
My son has an audi a4 and it has 211 hp..the Z has 330 hp yet the ft lbs of torque for the audi is 258 while the torque for the Z is only a bit more 270..120 more horses and only 12 ft lbs difference?
How can that be?


also I thought the bigger the displacement the more torque in the lower end but the audi has only 2 liter displacement while the z has 3.7 yet the audi's max torque is said to be between 4300- 6000 rep while the Z says its max torque is achieved at 5200 rpm..

Can anyone explain this?

Thanks

geosZ

The Audi is turbo?

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Dembflyr

Or Diesel?

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poorazn

(Torque x Engine speed) / 5,252 = Horsepower

A4: 211 hp @ 4,300 rpm; 258 ft lb of torque @ 1,500 rpm
370z : 332 hp @ 7,000 rpm; 270 ft lb of torque @ 5,200 rpm

My guess is the turbo in the A4's sweet range in PSI is between 1500 and 4300 and tapers off after that.

My talking out my *** btw.

red6spd

Its Turbocharged. Most Tubo powered cars are going to make a decent amount of TQ, thats why they can get away with having such a small engine (2.0L) in your sons A4. Dont worry because with a 0-60 time of 7.2 seconds for an Auto and 6.5 for a stick it dont matter how much TQ that little motor makes, its still slow LOL

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Red__Zed

in for bro-science

my2004Z

It's all about total power under the curve. VVEL FTW!

Guard Dad

The comments are pretty-much spot on. The Z gives up a little low speed power for a BUNCH of high speed power. The Audi system allows a small engine to feel and drive like a big motor in most situations but for highway passing (or even drag racing) the Z just blows the Audi away. Your 7 speed auto puts the Z in the sweet spot of the power band where we have a 121 HP advantage over the Audi. No contest.

Also keep in mind that torque is a "raw" number of force whereas horsepower is a calculation incorporating the raw torque number and engine speed (Revolutions Per Minute-rpm). What this means is that 200 lb/ft of torque at 2500 rpm represents only half the power of the same 200 lb/ft of torque at 5000 rpm and only 1/3 the power of the same 200 lb/ft of torque at 7500 rpm. Ever notice how high on the tach the Z makes its power? That's because the Z is designed to breath at high engine speeds, revs are our friend. It's also why we have 6 and 7 speed transmissions which allow the engine to get into the high rpm range as quickly as possible.

Methodical4u

I was always told by a friend who was a mechanic that you have cars that build torque quickly such as most V8's, but then have some engines that make their power through higher RPM's if you look at pretty much any dyno chart, you will see the Z builds smooth power that doesn't fall off until about what? 7200 RPM's or so? vs other cars that peak quicker but then fall on their face. Take my old 2010 Mazdaspeed 3 which had 280 ft. lbs of tq, and would pull really well from about 40 up to 100 or 120, however, the car MUST be kept at 5500-6000 RPM's or under otherwise the power is gone.

When you watch a car run the 1/4, you'll see some that run equal times, but the trap speed shows the HP... what does your son's car trap? What can most Z's trap? Some stock Z's trap 106-108 mph.

I don't know all of the little details... i'm basically just trying to show examples based on my very limited knowledge.

Red__Zed

The low end torque is partially a function of how the engine is designed, but in both examples here (Mazda/Audi), it is a function of the turbo.

Your Mazda ran out of steam up top due to turbo limitations. A lot of guys swapped for a more efficient turbo, which remedied the "out of gas" feeling up top.



OP--

Horsepower is nothing more than a function of TQ*RPM. More "torque" just means oomph down low, whereas more horsepower tends to indicate more spread out power.

The 370z has a pretty flat torque curve, generating moderate amounts of torque throughout the rev range. It's not particularly high, but it is ample.

The Audi has more gumph down low, but it runs out up top. I presume this is mostly due to poor turbo efficiency up top, but I'm not really familiar with the car.

Methodical4u

The MS3's had major fuel problems and needed either underhood fuel pump internals or whole new 700.00 fuel pump if you had more mods than a CAI with a TIP. With the new fuel pump the 3's could make more power but as you said the turbo would have to be swapped for something more expensive. If you could run a 13.5 in that car, you had spent a fair amount of money. I decided on the Z because I wanted something quicker out of the box myself.

But yeah I see what you're saying.

VQStryker

IMO and something I have noticed is that Japanese imports seem to make there most up top rather then low-low mid and is why there engines tend to rev high. On the other hand domestic cars, especially mustangs, rely more on there high low end tourqe and having a low rev....just something I think

forgot to mention that they have a longer stroke to create the high low end tq numbers but then peaks, drops. Of course modifications such as cams, valves, springs rods, and maybe some others will allow them to adjust the cars tq/hp at whatever rpm through tuneing. What this means is that the low end tq monster just became a car that no longer revs at 6-6.5k but now is safely at 7.5 maybe 8k with better high end tq......IMO

As for the MS3/Audi, you are all very much correct. The A/R would have ALOT to do with that. Higher the A/R is on a turbo the better your top end and seeing as the stock MS3/Audi would have to (in stock form) pass certain criteria, they probably gave them a smaller turbo with a smaller A/R.

Reason for it being better up top and being able to create more power in the long run is do the inducer side being larger and pushing it through the small exducer side creating alot more pressure then the smaller A/R turbos and being a larger A/R means it takes a little longer to build up rotational speed.
It also depends on the difference between the inducer and exducer sides of the turbo. Like with GTM TT kits (GT28RS .64 A/R and GT28RS .86 A/R) the smaller turbo will creat its max power faster and flatten out faster too where the larger turbo will take a bit longer but will not flatten out as quickly along with making more tq/hp.


sorry about the long post I couldnt stop talking

here is a VERY informative link for you guys, I just found it

TurboByGarrett.com - Turbo Tech102

Methodical4u

Also isn't there a formula for how much air the turbo flows into the engine increases displacement? Not literally of course, but it mimicks having more because of the higher pressure or whatever?

Chan Chee Hoe

Turbocharge is the way most Mfg going for in the future,even F-1 is using a turbocharged 1.6L in 2013 F-1,Big N/A like our 3.7L engine are dying soon,to save the earth from 'global warming'....i heard the next year BMW 5 series,is going to have 4 cyls turbo engine instead of their famous in line 6 engine.

gbrettin

So what you are saying is that all 370z owners should twin turbo our engines to get the low end torque.... I like your style.