what has more potential for power?

[HULK_I6T]

With the same displacement which design of motor has the better potential for power?

4000cc inline 6 or 4000cc V8?

Assuming a modern design in both such as multiple valves and cams.... which design would be more likely to produce more power with the same displacement.

[Falcon SXR8]

Probably the same power but the v8 will sound better doing it so it wins

[ratter]

what bore and stroke of each combination?

[Franco Cozzo]

That Toyota 1UZFE 4L V8 is a pretty neat engine:

The 4.0 L (3,968 cc or 242.1 cu in) all-alloy 1UZ-FE debuted in 1989 in the first generation Lexus LS 400/Toyota Celsior and the engine was progressively released across a number of other models in the Toyota/Lexus range. The engine is oversquare by design, with a bore size of 87.5 mm (3.44 in) and stroke of 82.5 mm (3.25 in).[1] It has proved to be a strong, reliable and smooth powerplant with features such as 6-bolt main bearings and belt-driven quad-camshafts. The water pump is also driven by the cam belt. The connecting rods and crankshaft are constructed of steel. The pistons are hypereutectic.

There is a lot of supercharger/turbo kits out there for them too.

[mechanic]

Originally Posted by Big Damo

That Toyota 1UZFE 4L V8 is a pretty neat engine:



There is a lot of supercharger/turbo kits out there for them too.

That sure is oversquare, at what rpm does it get it's HP and Torque?

[Sox]

Originally Posted by ratter

what bore and stroke of each combination?

I would imagine that in a hypothetical question such as this, we can assume that a bore and stroke ratio optimised for each cylinder config.

Otherwise it's a huge can of worms with numerous answers.

Considering this, the maximum outputs for each engine should be mostly similar.

[Nikked]

More cylinders = more valve area...

Does that mean more power though?

String, how long...

[Sox]

Originally Posted by Nikked

More cylinders = more valve area...

Does that mean more power though?

String, how long...

On first look, we might think this.
However if the bore/stroke is optimised for both, the valve area can be roughly the same.

[Franco Cozzo]

Originally Posted by mechanic

That sure is oversquare, at what rpm does it get it's HP and Torque?

Japanese versions are rated at 191kW at 5400 rpm together with 353Nm at 4600 rpm, while Australian delivered versions (from early 1990) make 1kW and 3Nm less. It is claimed that 90 percent of peak torque is spread from 2000 to 5600 rpm but, curiously, it doesn’t feel that way – the engine seems to come alive at around 4000 rpm.

Its not overly torquey, but it was fitted to the Lexus LS400 which was a big luxury car at the time in the late 80s/early 90s.

Someone on Fordmods has one in an E Series Falcon.

[AU1XLS]

If you don't like posts by any member put them on ignore
Anymore off topic posts and or digs will result in warnings being given

[FPV GTHO]

The V8 will have more exhaust pulses allowing a bigger exhaust without loss of scavenging, lighter pistons and smaller stroke allowing higher rpm peak. The 6 cylinder will be simpler and likely produce more torque though.

[mik]

Potential power = how big is your bank account ???

[Franco Cozzo]

Originally Posted by mik

Potential power = how big is your bank account ???

Thats it, its all about how much you want to spend, everything is possible with cars the only limit is $$$ and the five-oh.

[mik]

Originally Posted by Big Damo

Its not overly torquey, but it was fitted to the Lexus LS400 which was a big luxury car at the time in the late 80s/early 90s.

Someone on Fordmods has one in an E Series Falcon.

They are a nice little engine, I have one in my ls400, my young brother has 3 cars with 1uz donks, soarers (one super charged one na)and one sleeper na in a smaller vehicle, and I have done the glass of water trick on the engine, they really are a nice smooth donk.

[LoudPipes]

I'll take the one with the most useable torque.

[HULK_I6T]

Would have to assume engine configurations are optimised.

the reason I ask this question is that vehicle manufacturers seem to be fitting smaller boosted motors in bigger cars..

for instance mercedes is working on a 4000cc V8 to then turbo.

Why didnt they go for the 6 cylinder of similar capacity?

[dragons90]

I6 is too long for most cars that's why they go v6 or v8

[Sox]

Originally Posted by HULK_I6T

Would have to assume engine configurations are optimised.

the reason I ask this question is that vehicle manufacturers seem to be fitting smaller boosted motors in bigger cars..

for instance mercedes is working on a 4000cc V8 to then turbo.

Why didnt they go for the 6 cylinder of similar capacity?

The reason why manufacturers are heading in that direction is not just due to power.

Smoothness and packaging are also very important.

V8's are inherently quite smooth and quite compact for the amount of cylinders.
I6's are very smooth, but very long.
V6's are very compact, but full of vibes and are difficult to make smooth, needing balance shafts, etc.

[Nikked]

Originally Posted by HULK_I6T

Would have to assume engine configurations are optimised.

the reason I ask this question is that vehicle manufacturers seem to be fitting smaller boosted motors in bigger cars..

for instance mercedes is working on a 4000cc V8 to then turbo.

Why didnt they go for the 6 cylinder of similar capacity?

Because as I said earlier, more cylinders = more valve space (in most cases)...even better in boosted configurations. It was this thinking that brought the incredible BRM V6 into life...all 1.5 litres of it...


British Racing Motors took advantage F1 of the rule of allowing engines under 1.5 being boosted. BRM got the slide rules out and found that the V16 gave them the best total valve area...with a huge 2in stroke...


Not sure if the advantage is that great in this case (4L V8 v's V6), but I would imagine that there is some efficiency of displacement advantage...


Plus you can have "V8 Kompressor" badges on the car...********* awesome in any language.

[GASWAGON]

Still an I6 will use less fuel compared to a V8 plus they're very balanced even stock bottom end.....Look at the Nissan 3.0ltr engine Holden put in the VL commo....Great injected motor with only 3 ltrs.

[FPV GTHO]

Why would an I6 use less fuel, everything else equal?

[Windsor220]

Originally Posted by Sox

V6's are very compact, but full of vibes and are difficult to make smooth, needing balance shafts, etc.

I think you are thinking of old 90 degree V6s. 60 degree V6s are smooth and dont requre any balance shafts.

[Bent8]

Originally Posted by HULK_I6T

Would have to assume engine configurations are optimised.

the reason I ask this question is that vehicle manufacturers seem to be fitting smaller boosted motors in bigger cars..

for instance mercedes is working on a 4000cc V8 to then turbo.

Why didnt they go for the 6 cylinder of similar capacity?

Because AMG like V8's.. the push for smaller forced induction motors is to meet emissions requirements.

My bet would be on the V8 making more horsepower with peak torque arriving higher up the rev range than the same capacity straight six.

You could use the BMW E92 V8 (309kW@8300rpm) as a benchmark, but I doubt a straight six would be making that kind of power at those revs..

[XR Martin]

TVR made a 300kw+ 4L Inline six back in the late 1990s

[FPV GTHO]

Originally Posted by Windsor220

I think you are thinking of old 90 degree V6s. 60 degree V6s are smooth and dont requre any balance shafts.

Yes they do. They can't compare to the natural smoothness of a I6, V12 or boxer.

[dragons90]

Originally Posted by Bent8

Because AMG like V8's.. the push for smaller forced induction motors is to meet emissions requirements.

My bet would be on the V8 making more horsepower with peak torque arriving higher up the rev range than the same capacity straight six.

You could use the BMW E92 V8 (309kW@8300rpm) as a benchmark, but I doubt a straight six would be making that kind of power at those revs..

The previous 3.2 i6 E46 M3 made more power and toque per liter 252 kW 7900rpm 365 N·m and 265 kW 370 N·m for the csl edition
Also look at the GT3 RS 4.0 368 kW at 8250 rpm and 460 N·m of torque at 5750 rpm

[Bossxr8]

One factor to consider is the more cylinders, the more friction would be generated from 8 pistons/conrods etc Vs 6 pistons/conrods etc.

But then again those 6 cylinders would have to be bigger so maybe it would balance out. I doubt there would be much in it at all, all things being equal.

[HULK_I6T]

Why not a huge 4000cc 4 cylinder with vtec?

Discussion not limited to other types of designs. Just looking at a certain displacement and considering the options.. Let's say 4000cc

[XP6]

Given the same specs the V8 should pip the six in torque because of the extra power strokes per single revolution of the crank.

[yearby]

Getting back to the question-

"With the same displacement which design of motor has the better potential for power? 4000cc inline 6 or 4000cc V8?

The answer is the V8 and here is why.

Divide the 4000cc by 6 for the inline 6 cylinder and you will get 666.66cc
now
Divide the 4000cc by 8 for the V8 and you will get 500cc

First thing to notice is that inline 6 has a greater volume per cylinder than the V8 and this greater volume affects the amount of time for the flame front to cross the combustion chamber. The larger the volume, the more time the flame takes to cross the camber.

Now we are talking in micro seconds here, but if you think about the size of the atoms/molecules colliding inside the combustion chamber and their relationship to the size of the combustion chamber this a big deal on their scale.

Now the engine with the fastest complete burn time is the engine with the most potential, in this case the V8.

1. The V8 with it's faster burn time allows the torque curve to be raised up the rev range thus producing more power.

2. The faster burn time allows the fuel mixture to be leaned, (that is to run a leaner mixture under full throttle), a leaner mixture burns slower but releases more energy (heat) than a richer mixture, and this is compensated by the smaller combustion volume.

The evidence to support this would be the very high revving motorcycle engines doing 10,000 rpm plus. I guess it would be like bolting 8 small high revving engines together.


Peter