TomCat39

I not speaking about balance, I am talking about harmonics. And I do understand they are interrelated. As such V6 and V8 is naturally in balance I guess.

When I was researching about dampened pullies etc it was put very plainly that the inline 4 cylinder is limited in displacement due to vibrational harmonic challenges that even the best dampened pullies can only combat so far.

These same harmonic challenges are not present in 6 and 8 cylinders and I've heard also not present or if is present is not in the same manner on the pancake 4 cylinders (boxer engine).

I do believe you can make a 5.0L V6 but they don't, just like at one time thay made an inline 12 that was MASSIVE in size and weight with flat heads.

Example:
The 637 V8 was the largest displacement production gasoline V8 ever made for highway trucks. The largest engine derived from the series was a 702-cubic-inch (11.5 L) "Twin Six" V12, which was basically two 351 V6s placed end-to-end with a common block and crankshaft.

Divide that by two and that's over 5.0L per v6.

NotARaCist

iTrader: (1)

Right, but like you said, those were made for trucks. They could be made stupidly tall without having packaging issues. Like I said, bore:stroke. Go making an engine with a stupidly big bore and a tiny little stroke, and you'll have an engine that can't even move it's own rotating mass. With 4 cylinder engines, you have issues with secondary and rocking forces, but rocking forces can be dealt with via balance shafts (hello H series), and secondary forces can be dealt with by just not spinning the motor out to 8000. You have the same problems in an I5, I6, or I8 engine (yeah, they exist, and they're awesome as ****). It's just the nature of an inline engine. When you start talking about V engines, you have to look at cylinder angles, what kind of crank is being used, and all that other fun ****, but Honda decided that the J series needed two dampers (crank plus flywheel) for a reason. I'm inclined to trust that they know what they're doing when they put two on the J30A4, but only one on the B18C5.

TomCat39

So really, from what you are stating, inline motors are limited in displacement due to extra vibrational issues (secondary forces) that V and boxer motors are not.

Thus why the boxer 4 banger Porsche motor can be inherently larger than the inline 4.

Basically, configuration will set your limitations.

Am I understanding correctly?

Space under the hood is a moot point as the body and frame can be worked around all of that. If height was really an issue, there wouldn't be the giant blower motors etc or high risers dual carbs etc.

Derek Perez

I made this thread about the Jdm d15b vtec and how to configure this motor into your civic so no offense but I'm trying to help people with this stage 3 vtec setup,

BTW thread update! I just passed smog, this was the 4th time trying. And the reason I wasn't passing the first three times is because the d15b was stuck in 12v mode because my stock ecu couldn't operate the mid range vtec, causing the car to produce high noX! The car runs lean at low rpms in order to save fuel... I hope this helps someone I wish I could have found this exact information!