So; question, I understand that V8's grant you more power (typically) than a v6 or a four-cylinder. But if that's the case, then why do some racers out there use four-cylinder engines? (ex. Evo or STI) Is there more to it? I appreciate anyone's answer.
Comments
It’s a touchy topic
I will use F1 as an example
F1 cars are able to get 750hp currently out of their 1.6 litre V6s
But by doing this they go through an engine every few races. The life span of the engines is ridiculously low.
This is due to extreme compression/insane boosts/high revs
Pros and Cons of a V6 with 750hp:
light weight means better cornering and overall performance
Cons
Insane boost, high compression, and RPMs mean the engine isn’t as reliable
Pros and Cons of a V12 with 750hp
Pros
The engine produces the power at a lower compression and lower RPMs which means for a more reliable engine which will last quite a long time
Cons
A heavier engine means less performance/handling in the corners
So if you can afford it and you don’t mind your car breaking down more often go with the tuned smaller engine…. if you like a more reliable set up… go with the bigger lower compression motor.
Just to add as a form of extra clarification as well: If you have a low RPM, high displacement engine (large bore, long stroke, say an AMG 6.2 V8), it will be very reliable. Get a high revving, lower displacement (so small-ish bore, short stroke, say an M3 4.0 V8), it will be under more stress because it’s operating at higher revs to get the same power. Sometimes it’s not dependent on cylinder configuration or number, but the design. depends on application as you said.
For clarification, F1 cars make a lot of horsepower but not very much torque. They don’t need as much torque because they aren’t hauling around nearly as much ass as passenger vehicles.
For example, the 2006 2.4 litre Toyota RVX-06 V8 engine produces 740 bhp at 19,000 rpm and outputs 202 ft.lb of torque.
Rally cars are the opposite. They only make about 320hp despite shoving 40lbs of boost through a 33mm restrictor into a 2.0L engine, but they make a LOT of torque and it’s a broad curve.
V8 aren’t in light cars like Subarus partly because the massive low end torque would kill transmission life but mostly because of rally regulations. Also, the thick torque all across the power band would make the traction control crap itself (especially off road). Turbos give the chance for the tranny to live because all the power is in high rpm.
heard of anti-lag? what does the transmission have to do with anything? It’s regulations. Turbos provide torque. Torque is important because of air restrictors in rallying, so while you can’t have a lot of power, you can make a lot of torque at low rpms with turbos.
They’re lighter and not so complex. Also the rally regulations.
@ V-tech - I don’t think your answer is accurate. Turbos generate torque in a much harsher way than any V8 that is naturally aspirated. Race cars have smaller displacements due to the regulations therein. That’s it. Now in Europe, they have much more strict emissions, and most companies use their motorsports arms for R&D. In America, we have Nascar V8s and NHRA V8s that care little about emissions. Weight is also a factor, however, let it be known that an 5.7l Chevy LS1 weighs the same as a 3.2l BMW s54.
Everyone here is saying that V8’s are heavier than Japanese 4 cylinders.
Some, yes, but the LS engines (more specifically the modern ones) weigh less than most Japanese engines. This is due to the fact that because Japanese engines are usually 4/6 cylinders, they get turbo charged for a power increase, which add more weight to the engine.
Extra cylinders isn’t so much to make more power but to cancel out imbalances and smoothen up the power going to the wheels.
A 4banger has 1 power stroke per 720degree cycle, Whilst a v8 has 2 power strokes per 720degree cycle. However, a 6 litre 4 cylinder will have more torque than a 6 litre 6 cylinder because more of that power is happening at once, ect.
So it comes down to engine choice/use ect. Generally though they’re more compact, simpler and generally produce more usable power once peak tuned ect.
A peak-performance 5litre V8 is basically good for straight lines unless you have tonnes of downforce. :P
Weight reduction, bro!