Is a V6 better than an I6?

[Red Bread]

Can we agree that this V8
[IMG]https://static.carthrottle.com/works...8d51629793.jpg[/IMG]

Will almost certainly out handle this V6?
[IMG]https://icdn-6.motor1.com/images/mgl...irst-drive.jpg[/IMG]

And why do I suddenly want an LSx S2k?

[The Choosey begger]

Originally Posted by GuidoK

The e36 m3 was never developed as a homologation model.
By that time only Mercedes, Opel and Alfa homologated to the class 1 dtm.
Max specs for those seasons (1993-1995) were 2,5L 6cyl. The e36m3 has a bigger engine so no go. And in 1996 DTM stopped.


It also doesnt change the fact that you're making stories up in this thread....

But you're completely right, if a designer cannot place an i6 into his design (for instance he doesnt want to offer up the required cabinspace ), a more compact layout can be getter.
Of course you have to come over the fact that the i6 has a better balance, is easier on flow and thermal management (it has a distinct cold and hot side) etc etc. compared to a V6 setup
So all people with an engineering background will answer the question with the same as what was already given in the first reply of this topic: "it depends".
Its mostly the people that dont have an engineering background that luster for an answer that is conclusive in ALL situations, as that would make it easy to understand. Alas it is not that easy.

You can't argue the physics behind how various engines affect handling, so you turn to your lil gotcha games on trivia knowledge or spelling etc to discredit valid points.

The E30 M3 was designed for the FIA's homologation..

FIA ( La Fédération Internationale de l'Automobile)

Born of FIA Group A homologation rules requiring a minimum production run of 5,000 units, BMW's E30 M3 answered the challenge laid down by the Mercedes 190 16V in the German and European Touring Car Championships.

In the US in grassroot racing, SCCA, NASA cars like S2000's, Porsche Cayman do better than BMW's and Porsche 911's.

When all cars are modified, similar horsepower, all of sudden, better designs, lighter cars do better.

[The Choosey begger]

Originally Posted by GuidoK

I'm not angry, you're just making things up as you go, presenting them as facts.
The e30 m3 was developed as a homologation model. That means[b] it has certain specs to follow in order to compete in that class.[/by

BTW the 4 cyl s14 in the e30 sits almost as far foreward as the later i6 in the e36:






Look at its position compared to the strut towers or the wheel wells.
Its all a matter of how you design a chassis.

Originally Posted by GuidoK

I'm pretty sure they didnt chose the I4 because of that. You're making that up while you're typing it.

The FIA class A had a displacement limitation not number of cylinders limitation.

Lookbat the gap between both engines and the radiator.

[Red Bread]

Gap from the radiator to the front of the engine doesn't mean anything aside from one can accept a longer engine (like an I6.) The E30 still had the engine further forward (and those scary/fun rear trailing arms.)

[overcoil]

Originally Posted by Red Bread

Gap from the radiator to the front of the engine doesn't mean anything aside from one can accept a longer engine (like an I6.) The E30 still had the engine further forward (and those scary/fun rear trailing arms.)

Look at the caster of the e30 strut mount, be interesting to see how the engines align with wheels centerline.

[The Choosey begger]

Originally Posted by ScottSinger

Look at the caster of the e30 strut mount, be interesting to see how the engines align with wheels centerline.

Exactly, good catch!

[GuidoK]

Originally Posted by ScottSinger

Look at the caster of the e30 strut mount, be interesting to see how the engines align with wheels centerline.

Actually the difference in caster between e36m3 and e30m3 is about 2 degrees. about 6,5deg for the e36 and 8,5deb for the e30
If an average strut is about 30" long the shift of the strut tower backwards is easily calculated.
Actually I'd like to see anglo do that, as he seems to know everything once people tell him how everything works
Basic trigonometry

[The Choosey begger]

Originally Posted by GuidoK

Actually the difference in caster between e36m3 and e30m3 is about 2 degrees. about 6,5deg for the e36 and 8,5deb for the e30
If an average strut is about 30" long the shift of the strut tower backwards is easily calculated.
Actually I'd like to see anglo do that, as he seems to know everything once people tell him how everything works
Basic trigonometry

It's not that complicated, if you put a more compact V6 in place of an inline 6, it'll move the weight and balance in the right direction and improve handling.

You want the weight between axles not over the axles for optimal handling.

Contrary to what you think, the FIA's rules were on displacement not number of cylinders and DTM just followed FIA's classing and rules.

You need google your points more carefully! Hahaha

[Efthreeoh]

Originally Posted by bobert

Ok - it just threw me off in the original post cz you didn't qualify the statement in question as such. No worries.



No need to be so sensitive - just wanted to point out that one sentence that jumped out at me in an otherwise fine post. Congrats on your driving history.

It's all good. I could have been a bit more precise. A flat 6 is just a V6 splayed out all the way to 180 deg., which let's the crank angles get back to counteracting the rocking couple effect.

[Efthreeoh]

Originally Posted by anglo

It's not that complicated, if you put a more compact V6 in place of an inline 6, it'll move the weight and balance in the right direction and improve handling.

You want the weight between axles not over the axles for optimal handling.

Contrary to what you think, the FIA's rules were on displacement not number of cylinders and DTM just followed FIA's classing and rules.

You need google your points more carefully! Hahaha

Well I think engine length and it's position within the chassis affecting handling is more of a concern with race cars than street cars. At limits on the track is where it matters. BMW, well at least up until the advent of electronic stability control, made every effort to get a 50/50 weight balance and get as much chassis weight between the axles. The I6 is placed as far back as possible to get a 50/50 balance. Since the majority of BMWs and cars in general are designed for street use and all are well capable of performance far beyond legal and sane levels of driving, I think the use of the I6 is still a reasonable balance between NVH and handling balance.

That said, let's not get into the Subie WRX I was chasing last night on the way home from work. It was fun to see how well my E90 could keep up on a great back country road (no traffic) against a front weight imbalanced AWD performance car; it was purely for scientific reasons of course

[GuidoK]

Originally Posted by Efthreeoh

made every effort to get a 50/50 weight balance and get as much chassis weight between the axles. The I6 is placed as far back as possible to get a 50/50 balance.

In case of a 3.0si z4 its 50.1/49.9% according to bmw specs.
I'd say thats spot on!
Maybe if the washerfluid tank is half empty its 50/50

[Efthreeoh]

Originally Posted by GuidoK

In case of a 3.0si z4 its 50.1/49.9% according to bmw specs.
I'd say thats spot on!
Maybe if the washerfluid tank is half empty its 50/50

I use light-weight washer fluid with a specific gravity of <1.0 It's expensive though...

Okay, I'm off to drop the fuel tank in the Hummer.

If I'm not back in a while, my fire extinguisher failed.

[floydarogers]

IMO, all the discussion regarding "handling" and 50%/50% is off base.
While a 50/50 makes for a nice neutral handling car with good performance, it's mainly a benefit for the more common daily driver than for race cars.

Let's not forget that a mid-engined layout is readily acknowledge as the best for real performance and handling (even Porsche recognizes that fact and has limited power in the Cayman so that the older rear-engine chassis still wins out.) Frankly, my NSX (still miss that car), with it's 60-degree V6 ripping to 8K redline handled much better than my son's E92 335i (which is just as fast as the NSX, btw).

Let's not forget that F1 cars use the engine (V6/V8) as a structural element, holding the front cockpit and front suspension together with the rear end. A V6 is far superior in that layout than an I6 could ever be.

You can also point out the spec racing that took place in the E46 era, pitting a 320i against Acura/Honda and a couple other spec racing cars. The BMWs actually didn't do very well against the others, even though all the others were front-engined.

[1MOREMOD]

E46 made a rear engine?

[GuidoK]

Originally Posted by floydarogers

Let's not forget that F1 cars use the engine (V6/V8) as a structural element, holding the front cockpit and front suspension together with the rear end. A V6 is far superior in that layout than an I6 could ever be.

Why exactly would a v6/v8 be "far" more superior in that layout other than that the I6 is longer and takes up more space?
Its not that an I6 block is less strong; you can make the walls/casting as thick as you want and in whatever shape you want.

[floydarogers]

Originally Posted by GuidoK

Why exactly would a v6/v8 be "far" more superior in that layout other than that the I6 is longer and takes up more space?
Its not that an I6 block is less strong; you can make the walls/casting as thick as you want and in whatever shape you want.

Come on, now, you know the answer. A V6 is short and bigger in cross-section. Essentially it's a bigger and shorter beam than a long and narrow I6. Polar moment of inertia rules when it comes to stiffness.

[floydarogers]

Originally Posted by 1MOREMOD

E46 made a rear engine?

Read again. I never said that.

[1MOREMOD]

Even though all the others are front engine implies the e46 is something else. Explain it to me

[Red Bread]

Originally Posted by floydarogers

Read again. I never said that.

You did, actually. I assume you meant to say front wheel drive, concerning the others, not front engined.

[1MOREMOD]

Originally Posted by Red Bread

You did, actually. I assume you meant to say front wheel drive, concerning the others, not front engined.

Same

[GuidoK]

Originally Posted by floydarogers

Come on, now, you know the answer. A V6 is short and bigger in cross-section. Essentially it's a bigger and shorter beam than a long and narrow I6. Polar moment of inertia rules when it comes to stiffness.

You can make the I6 just as wide as an V6. You can cast all kinds of reinforcementridges onto a blok in the casting proces, they do that also with the v6 as all mountings front and rear dont have the exact shape of the v6 minimum outline.
And as for lenght, F1 raced with v12's for years, and they are as long as an I6.

I think the main advantage is that in theory you can make a V6 lighter.
But -putting it in the perspective of this topic- it does have to be made lighter.
If you look at masses of V6 engines in normal cars, they are on average not really lighter than I6 engines. There are more valvetrain components etc that weigh in.
And that can also translate in weight distribution. Like I said a z4 3.0si has a 50.1/49.9 weight distribution. Cars from the competition like for example a v6 equipped merc slk can not produce such optimal numbers.
What in theory can be an advantage or not still has to be made in reality.
I mean look at the current M3: thats also 50/50 (I think the exact numbers are 49.6/50.4).
Mercedes c43 AMG (quickest v6 merc): front 55% - rear 45%
The theoretical debate is interesting, but its the numbers in reality that determine it in the end. And reality is that a lot of v6 equipped cars have a worse weight distribution than bmw's with i6.

[floydarogers]

Originally Posted by GuidoK

You can make the I6 just as wide as an V6. You can cast all kinds of reinforcementridges onto a blok in the casting proces, they do that also with the v6 as all mountings front and rear dont have the exact shape of the v6 minimum outline.
...
And that can also translate in weight distribution.

Weight is very very very important in a racecar. You don't want to add weight (to an I6) to make it as strong as a V6.

Again, all this talk of even weight distribution is misdirected. A mid-engine design with around 60% on the rears and 40% front is by far the best handling design. 50/50 just isn't as quick in chicanes and in initial turn-in.