iridebmx

iTrader: (6)

Now we all know the 2JZ can reach some incredible numbers with a turbo but what about N/A???

I have been driving a 320i for the past 2 months and don't understand how the BMW inline 6 is so much faster without a turbo? I know they are high compression motors but why are BMW inline 6's in the 300's?

Just wondering why really.... i have no idea, is it just easier and cheaper for the 2jz to go boost? or are the bmw's pretty much built all motor engines?

SChema

iTrader: (2)

Yes, you have answered your own question. The majority of the power difference is in it's compression and flow efficiency. Even though the 2JZ has produce in excess of 1000 horsepower with boost, we have to remember that the head on our motors are not that efficient. One more thing, never rely on peak numbers, the power under the curve is what really counts.

czar07

isnt a 320 an inline 4?

you cant go comparing a brand new engine(i assume you are) to a design which is almost 20 years old.

iridebmx

iTrader: (6)

^well even the older m3 motors could be built with a lot more power than a all motor 2jz.... and no euro spec 320i's are inline 6's(m50) but cannot be built as powerful as the higher 3 series engines (m52)...


basically from what ive been reading up on. bmws have shorter stroke and wider bore thus making more HP and less torque. just like most I6's

BLK13X

That goes for nearly all Japanese engines of the 90's, have a look at Nissan's RB25DE, not much squat compared to the RB25DET, let alone the RB26.

The short stroke/wide bore of the German I6 engines sounds awfully nice when opened up though.

OT time...
It probably comes down to logical thinking for a mainstream corporation and bottom line figures. I mean, if the engineers of the JZ family engines were given a brief to make as much power possible without any forced aspirations I'm sure that they would've done so.

For a major manufacturer it just seems to make more economic sense to either go for something tried and proven for them, such as decent (back then) power, reliability with not too high compression ratio or have a mildly worked version of the engine in turbocharged form. Proven reliability is key, and while it's always good to see manufacturers trying different combos, Toyotas has played it pretty safe until recently (and seemed more of a forced move in general terms) with the introduction of cars like the IS-F and LFA. Yes there was the turbo Supra and what not but as stated it comes from Toyota's book of tried and tested engine techniques.

I'm sure that within the next few generations of Toyotas they will start to take notice of what can be done with N/A engines. I just find it a little disappointing that they have nearly completely discontinued all F/I variants (besides diesels, in Australia anyway).
/OT