esanmiguel

Though I have the ATC 180HP version, I am still amazed at the power this engine produces (specifically the low-end torque). I have driven 6 cylinder cars before that dont feel as powerful. Owned a 325is before and the M50 engine is a nice engine but my TT still feels more powerful. I have also had plenty of experience with the Mercedes C230 Kompressor (1.8 liter supercharged) while it has very good "pull", the engine is unrefined, loud, and trashy. The Audi is a contrast being smooth all through its RPM range. I think I read somewhere where the 1.8T is an over-square engine? Not too sure exactly what over and under square really means and why each company would design their engines to be one or the other. Can anyone explain?

RedRoadster

And it means that stroke is longer than the bore is wide. A design that is generally good for producing low-end torque and good driveability over ultimate top end hp. Oversquare means bigger bore, shorter stroke, and in general produces the opposite characteristics. I can't think of any common VW/Audi engines that are oversquare from the factory - why they are good daily drivers.

Cruzad3r

so John, who's driving the GTI? or you take turn each day?

esanmiguel

Im pretty sure the VQ35 is oversquare then. If oversquare produces the opposite characteristics over undersquare, then it does not seem that way having driven a 350Z which has gobs of low end torque and not to bad on the high end. I would also assume that the Honda S2000 must be an oversquare design as well?

RedRoadster

doesn't mean that every example of an oversquare motor will be a torqueless wonder, and every undersquare car is going to be a stump-puller; just that the respective designs (over or under square) tends to promote those characteristics. I don't know what the bore v. stroke of the Nissan is, or what it feels like to drive, but I'm sure that its large displacement engine helps make up for what might otherwise be a design that could produce a somewhat peaky motor.

RedRoadster

but living in the city, the GTI is for occasional duty plus weekends and passenger/cargo hauling tasks, and the Boxster, sadly, is strictly weekends at this point...

RedRoadster

Stroke is only about 5mm longer than cylinder bore is wide. Almost equal.

Cruzad3r

siiiiigh such a pity

TTinCT

have shorter gearing in the first 4 gears....hence the reason on most 6 speeds you cannot reach 60mph in second gear.

mad scientist

...longer stroke demands higher piston speed for a given rpm. If piston speed is your limitation, then it is easier to build a high rpm engine with a shorter stroke than a longer one to keep piston speeds down. Consider also the energy required to get the piston up to speed, slow it down... and the resultant strains on the con rod. Lighter weight parts or lower speeds are necessary to keep these forces down. Tighter tolerances and stonger rod bolts are the alternative.