HP Torque

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