As near as I can determine, there are very few inherent advantages to a smaller displacement engine. About all I can think of is that it (may) be able to rev higher and it's obviously gonna be somewhat lighter. Probably better gas mileage, too. Now, sure, there are specific engines that are good for a reason (like the Supra's insanely strong bottom end), but in general, does anyone know of a reason to choose a low-displacement, import-type vehicle for a project car? It seems silly to me, but I want to make sure I'm not missing something.

 

Gas mileage is the biggest advantage of a small engine. It seems some people who are into imports do it because they were givin thier first car and it kinda stuck.

 

If you have a set HP in mind like 400hp. You would be better off as far as efficiency to run a bit of boost with a smaller displacement engine to get to the hp than to boost a bigger displacement engine a little to get to it.
an example would be:
a 200cid engine running 12psi of boost to get to 400hp would be more efficient than a 300cid engine running 7psi achieving 400hp

 

Torque. Smaller engine makes less torque.


A smaller engine may perform same as a bigger engine, say a 400 horse four banger VS 400 horse v-8. But in terms of it lasting, bigger engine will last longer, much longer. While the smaller engine will brake more often, and will have very short life in comparison to the bigger one.

Engine geometry also plays a role. A V-8 is more efficient than an inline-4. An inline 6 is more efficient than a V-8. This is all due to vibrations on the crank, depending on cylinder arrangement these vibration will rub power.
http://www.autozine.org/technical_sc...ne/smooth1.htm
http://www.autozine.org/technical_sc...ne/smooth2.htm
http://www.autozine.org/technical_sc...ne/smooth3.htm
http://www.autozine.org/technical_sc...ne/smooth4.htm
http://www.autozine.org/technical_sc...ne/smooth5.htm

 

With your argument, a 500rwhp 5.0 with stock block and rotating assembly would outlast a 500rwhp Forged 4 cyl. Just doesnt make sense. Stock 302 block wants to flex at 500 crank HP. There are a whole lot of boosted Evo's and STI's that run way more HP than most of us and are still well within the engines limitations.

Engine longevity depends on way way way to many factors to be able to say "That motor will outlast that one". You could have a fully forged 347 with a World block, if you dont keep up with maintainance or run it in the red zone all day, I doubt it will last very long. A boosted engine can last just as long as any other motor as long as it is maintained and properly setup/tuned.

Also I belive a nicely balanced rotating assembly would get rid of a lot of vibration worries.

 

No buddy, a 500 horse cast iron block and head 5.0 V-8 will outlast a 500 horse cast iron block and head 2.0 I-4. Also, a 1000 horse forged aluminum block and head 5.0 V-8 will outlast a 1000 horse forged aluminum block and head 2.0 I-4.

Bigger engine is more durable than a smaller engine, makes more torque too. Just think a garbage truck with 12.0L I-6 diesel VS a garbage truck with 1.8L I-6 diesel. Ummm. [:'(]

 

I was going to argue the same point. Kudo's 94Cbra!

The smaller will be more efficient because of the smaller rotating mass & less friction.

 

No buddy...

How can you make these assumptions?? Where are you getting this information? Why do you think one will outlast the other? Engine longevity is all about maintenance and if the application is correctly setup and tuned.

Ok, so your telling me that if both engines are running the correct components and correct tune, that the 4cyl will ruin before the V-8?? How can you say that? What factors are you using to contribute to catastophic engine failure?? There are just WAY WAY to many factors to take into account to say one will outlast the other. Why is this so hard to you to understand? There are plenty of 600hp Evo's that would last just as long as any V-8 be it they keep up with system maintenence.

Umm? Ok? In your earlier post you wrote this...

Your argument is "The bigger the engine the longer it will last." Then you go on to say "An inline 6 is more effecient than a V-8 due to crank vibration". According to you, a 7.3L Ford Powerstroke V-8 will outlast any Dodge 5.9L Cummins because the Ford is bigger. Also according to you the Cummins will outlast the Ford because an I-6 has less crank vibration? Vibration and oil starvation are what wears engines. Which is it? The Ford is the larger engine but Cummins diesels are known for their longevity yet are the smaller engine?

With your argument, your 4.6 would outlast any 4 or 6 cyl on the planet. The real world just isnt black and white like that. I'm for certian there are plenty of V-10 Viper engines that havnt lasted anywhere nearly as long as some stock Ford 302's or Import 4cyls have. This means ALL GM 350's will hands down, no questions asked, 100% of the time, outlast ANY Ford 302. Again, according to you, all Viper V-10's and Ferrari V-12's should last AT LEAST more than 300K miles... [&:]

My point is that if the two engines are correctly setup to take 500HP, you cant say one will outlast the other. The reason why engines of different sizes fail in the real world could be anything from a certian piston ring used in engine A to a weak block used in engine B. You think all 5.0's will outlast all 4.6's? I guarntee my Cast iron heads will warp before the heads on a 04 Cobra. And Id bet just about any EVO or STI engine could reliably take twice the HP that my engine could take.

I recommend you stop using google....

 

I read yours and I see that you're confused. You haven't read my first one right, and jumped to wrong conclusions. I'm not even going to waste my time arguing with you, all one has to do is read yours and mine and understand that you don't get it and argue for no reason here.

(HINT: size of engine and geometry mentioned is two different things.)

(A BIGGER HINT: click those links included to learn something.)

 

Im not the only one who noticed your arguments didnt make sense, FoxGT even said somthing about your ignorant post, and hes a very knowledgable member of this board.

You specifically stated a larger engine will outlast a smaller one which is completely and totally false.

Thats complete bullsh-t. How am I confused? You said between a 400hp 4cyl and a 400hp 8cyl, the V-8 would always last longer. Again, bullsh-t. To many factors to take into account. IT ALL DEPENDS ON HOW THE ENGINE IS SETUP AND TUNED.

If you read my argument correctly you would understand what Im saying. Anyone reading this thread will see that your the one confused. Your "inTarneHt" website you keep posting only discusses engine vibration associated with different engine configurations.

Once again, its nice to see how proficient you are with Google.