Talk:Undersquare

I once again took the liberty to add extra information to this article. Hopefully it is correctly done...

Anonamous engine enthusiast 23.8.2005

I was wondering, that is there anyone who has ever driven a car or another vehicle that has an undersquare engine? I have driven a couple and must admit that these long-strokers are nice to drive even if they are not so powerful. The low rpm power feels nice and makes the engine to feel more powerful than it really is making the driving effortless and leisury. I must say that it is an extreme shame that this type of engines are not manufactured nowadays. At least, not in the passenger cars. And the typical overquare ones are so hightuned in addition to their naturally poor low-rpm operation-capabilities that they are terrible to drive in a city or town at least here in Finland where city speed limits are as low as 40-50 km/h (about 25 to 32 mph). When driving around with such speeds and considering the amount of lowspeed acceleration the longstroker's power disadvantage is offset by the enviroment, and their wide rpm powerband and low rpm torque more than makes it up.

Anonamous machine-enthusiast from Finland 10.10.2005 (day.month.year)

MG Rover K-Series Notes
All MGRover K-series engines have long strokes. One must bear in mind that the K-series was originally intended for the Metro/100 and other compact cars eg 200/400, in 1.1 and 1.4 and eventually 1.6 litre forms. This engine however, was highly adaptable. In 1.8 in-line four and V6 forms, the engine is one of the most lightest in its class and produces lots of torque. Compare the performance figures to the Honda S2000 engine, which may have higher power, higher revs are needed to produce this power and, the maximum torque does comes in a lot higher in the rev range.. Try removing a 1.8 K-series engine from a Land Rover Freelander and replace it with a Honda S2000 engine, you will have something that feels like a lawnmower engine failing miserably to pull a 4x4!

The 'K' is actually a very good block which only had one design fault - this was with the cooling system. Before MG Rover went bust, Powertrain, their engine development company, were working on a completely new head to pass Euro V emissions and to fully rectify the cooling problems. They also increased the bore to 2 litres which would have made it the torquiest and lightest engine in the 2 litre class... Many other problems experienced by Lotus, Caterham and various engine tuners, were actually engineered into the engine - Indeed, Lotus VHPD version had no MGRover input at all!! To explain it all, go to these sites, I think you might find them interesting...

King K-Series

K-Series Development Story

Iron Duke?
Why is the Iron Duke here? It has a 4-inch bore and 3-inch stroke (according to it's page), which is most decidely oversquare.--Sable232 04:32, 10 October 2006 (UTC)

Honda undersquare engines
Stock US Acura Integra GSR from 94-01 came with a B18C1 engine, 81mm bore and 87mm stroke. RS/LS/GS cars came with a B18B1, 81mm bore and 89mm stroke. While both are undersquare engines according to this article, the B18C1 is decidedly not undersquare in its behavior, making peak torque at 6,200 rpm, peak horsepower at 7,600 rpm, and hitting an 8,100 rpm redline. US Acura Integra Type-R with its B18C5 had the same 81mm bore and 87mm stroke, but pushes the powerband even higher with peak torque at 7,000 rpm, peak horsepower at 8,000 rpm, and an 8,400 rpm redline.

Not sure of all the details, but the Japanese Prelude Type-S managed a 7,500 redline with an 87mm bore and 90.7mm stroke. US 1992-1996 Prelude Si with its H23A1 had an 87mm bore and 95mm stroke.

Non performance oriented Honda undersquare engines include the B20B and B20Z (CRV) with 84mm bore and 89mm stroke, and any D series engine from the Civic line (D17A1 from 2001-2005 Civic DX/LX with 75mm bore and 94.4mm stroke for example).

I think the last paragraph from the article needs to be changed. Nowadays, undersquare engines tend to be quite rare, but this form of engine is still used in some applications. With every Civic from 1987 until 2005 except for the 1999-2000 Civic Si having an undersquare engine, they don't seem all that rare to me.

Jeremymatsuoka 22:36, 12 December 2006 (UTC)