i owned a mazda 626 with the 2.5 V6 for several years. not a bad engine. a little more torque would have been nice but the mileage was not bad. the only problem i had was a leaking oil pan gasket that cost a fortune to get fixed. sold it to a neighbor who still has it. 220k miles on it now. leaves a trail of blue smoke until it gets warmed up.
Thoughts on Smaller V-6 Engines
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Originally Posted By: Tosh
the best configurations for smoothness/lack of vibration in order are: V12, I6, V8, I4, V6, I5, I3. I noted (and was surprised) that I6 is better than V8 and that V6 was worse than I4. I can't get to the book just now, so I can't answer any questions (and I wish I remember where H6 and H4 fell).
Boxers have a funny horizontal rocking couple, but are sort of OK.
The Buick V-8 to V-6 conversions (or the PRV V-6) are the nastiest way to get a V-6...balance shafts are certainly worthwhile from a vibration perspective, but add extra friction.
My first car had a 138 c.i. pushrod straight 6. You could balance a coin on the rocker cover at idle. Current beater has a similar sized 6, and I love it.
A 2 litre V-12 would be awesome...and expensive and wasteful.
I (personally) think that cylinders should be around 500cc for petrol engines.
the best configurations for smoothness/lack of vibration in order are: V12, I6, V8, I4, V6, I5, I3. I noted (and was surprised) that I6 is better than V8 and that V6 was worse than I4. I can't get to the book just now, so I can't answer any questions (and I wish I remember where H6 and H4 fell).
Boxers have a funny horizontal rocking couple, but are sort of OK.
The Buick V-8 to V-6 conversions (or the PRV V-6) are the nastiest way to get a V-6...balance shafts are certainly worthwhile from a vibration perspective, but add extra friction.
My first car had a 138 c.i. pushrod straight 6. You could balance a coin on the rocker cover at idle. Current beater has a similar sized 6, and I love it.
A 2 litre V-12 would be awesome...and expensive and wasteful.
I (personally) think that cylinders should be around 500cc for petrol engines.
I've got a 3.8 intercooled turbo V6 in my good old 1987 Buick Grand National that is smooth, and fast as anyone who knows these cars already knows and I get high 20's MPG around town if I drive sanely. Plus, the exhaust sounds like a V8. So, it can and has been done.
The H4 is similar to an I4 in terms of balance. But the H6, like the V12 and I6, is naturally balanced:
http://en.wikipedia.org/wiki/Engine_balance
http://en.wikipedia.org/wiki/Engine_balance
I just pulled that info off Wikipedia. Do you think it needs editing? Here's what it says about the flat 6:
"The three cylinders on each side of the crankcase tend to have an end-to-end rocking motion, like a pair of straight-3 engines, but in the usual boxer engine configuration, the imbalances on each side cancel each other, resulting in a perfectly smooth engine."
http://en.wikipedia.org/wiki/Flat-6
I can certainly visualize how it wouldn't be perfect as long as the opposing cylinders are offset, which I think they'd have to be to share the same crankshaft. Wouldn't this cylinder-offset imbalance apply to a V12 engine as well, though to a lesser degree due to the higher cylinder count?
"The three cylinders on each side of the crankcase tend to have an end-to-end rocking motion, like a pair of straight-3 engines, but in the usual boxer engine configuration, the imbalances on each side cancel each other, resulting in a perfectly smooth engine."
http://en.wikipedia.org/wiki/Flat-6
I can certainly visualize how it wouldn't be perfect as long as the opposing cylinders are offset, which I think they'd have to be to share the same crankshaft. Wouldn't this cylinder-offset imbalance apply to a V12 engine as well, though to a lesser degree due to the higher cylinder count?
Years ago I had a buick V6 in Vega. It got the same fuel economy as the original 4 banger. This was with a bigger cam, headers and a 4 barrel carb. It had the power of a small stock V8.
How about a 2.8 liter V8?
http://www.h1v8.com/page/page/1562068.htm
It makes 400 horsepower @ 10,000 rpm with street cams. Check out the dyno video, it sounds great. It's also really small, someone has one of these in an Ariel Atom!
How about a 2.8 liter V8?
http://www.h1v8.com/page/page/1562068.htm
It makes 400 horsepower @ 10,000 rpm with street cams. Check out the dyno video, it sounds great. It's also really small, someone has one of these in an Ariel Atom!
Prolly nit-picking.
Look at a boxer, and there's a crank web between the two paired cylinders (to get the 180 degree offset...the bores are a big end width plus the crank web). Common pin V engines have an offset of only a single big end width (although some buick V-6s had offest big-ends), so the rocking couple is reduced...as you say, the length of the crank in relation to the rocking couple diminish the effect.
The Big V aero engines (and tank engines) had a pivot pin on the big end so that the cylinders were in plane (and a single bearing).
I think BRM managed to get rid of the issues with their "H" 16.
Look at a boxer, and there's a crank web between the two paired cylinders (to get the 180 degree offset...the bores are a big end width plus the crank web). Common pin V engines have an offset of only a single big end width (although some buick V-6s had offest big-ends), so the rocking couple is reduced...as you say, the length of the crank in relation to the rocking couple diminish the effect.
The Big V aero engines (and tank engines) had a pivot pin on the big end so that the cylinders were in plane (and a single bearing).
I think BRM managed to get rid of the issues with their "H" 16.
Originally Posted By: Shannow
Look at a boxer, and there's a crank web between the two paired cylinders (to get the 180 degree offset...the bores are a big end width plus the crank web). Common pin V engines have an offset of only a single big end width (although some buick V-6s had offest big-ends), so the rocking couple is reduced...as you say, the length of the crank in relation to the rocking couple diminish the effect.
After reading it over a few times and looking up a couple of words, I follow what you're saying! I'd guess that the Flat 6 would follow the V12 and the I6 in terms of natural smoothness.
I just began picturing the V12 as operating like separate I6s, so it wouldn't even matter that they're offset by a big end width because they're just two naturally balanced engines connected together and providing twice as many power pulses per revolution as a single I6, aiding smoothness but not balance (since the I6 is already balanced). Am I correct? This is the first time I've actually thought about engine balance.
Look at a boxer, and there's a crank web between the two paired cylinders (to get the 180 degree offset...the bores are a big end width plus the crank web). Common pin V engines have an offset of only a single big end width (although some buick V-6s had offest big-ends), so the rocking couple is reduced...as you say, the length of the crank in relation to the rocking couple diminish the effect.
After reading it over a few times and looking up a couple of words, I follow what you're saying! I'd guess that the Flat 6 would follow the V12 and the I6 in terms of natural smoothness.
I just began picturing the V12 as operating like separate I6s, so it wouldn't even matter that they're offset by a big end width because they're just two naturally balanced engines connected together and providing twice as many power pulses per revolution as a single I6, aiding smoothness but not balance (since the I6 is already balanced). Am I correct? This is the first time I've actually thought about engine balance.
Originally Posted By: parimento1
How would you guys like to see smaller V-6 engines in midsize cars that are smoother than 4 cylinder engines, but get similar gas mileage. One that comes to mind is the old Mazda 2.5L and the Dodge 2.7L as notorious for sludge as it was, it got pretty good MPG even with the 4 spd auto. Toyota announced today thet will be producing a 2.7L V-6 with a 6spd automatic, so maybe this is the future. Honestly, who needs 270hp in a camry family sedan? I'd rather have 190hp from a small V-6 and call it a day and keep my license. I also like the smaller V-6s better than the I-4 because it is much smoother and much less noisy/thrashy at high RPM. Let's hear what you guys think!
I would like to see manufacturers using smaller engines. I think that the current engines are far too large. For example, Toyota previously used the 3.0L 1MZ-FE in its Toyota Avalon from 1995-2004. Since 2005, they have used the 3.5L 2GR-FE when they could have went with the 2.5L 4GR-FSE which outputs the same horse power as the 3.0L 1MZ-FE, but should get much better fuel economy.
How would you guys like to see smaller V-6 engines in midsize cars that are smoother than 4 cylinder engines, but get similar gas mileage. One that comes to mind is the old Mazda 2.5L and the Dodge 2.7L as notorious for sludge as it was, it got pretty good MPG even with the 4 spd auto. Toyota announced today thet will be producing a 2.7L V-6 with a 6spd automatic, so maybe this is the future. Honestly, who needs 270hp in a camry family sedan? I'd rather have 190hp from a small V-6 and call it a day and keep my license. I also like the smaller V-6s better than the I-4 because it is much smoother and much less noisy/thrashy at high RPM. Let's hear what you guys think!
I would like to see manufacturers using smaller engines. I think that the current engines are far too large. For example, Toyota previously used the 3.0L 1MZ-FE in its Toyota Avalon from 1995-2004. Since 2005, they have used the 3.5L 2GR-FE when they could have went with the 2.5L 4GR-FSE which outputs the same horse power as the 3.0L 1MZ-FE, but should get much better fuel economy.
For smaller displacements, increased complexity of a V-6 is why I'd prefer a 2.5 liter 4 banger. Sure, my Subaru engines rock back and forth when you hit the starter...but, at idle, they are virtually vibration-less. At anything over 1000 rpms, it doesn't feel any smoother or rougher than my 4.6 liter V-8.
For sound, I like the straight six and V-8's the best. (But, I haven't heard a V-10 or V-12 or I-3...actually, I have heard an I-3 in a BMW motorcycle.
For sound, I like the straight six and V-8's the best. (But, I haven't heard a V-10 or V-12 or I-3...actually, I have heard an I-3 in a BMW motorcycle.
so where do the I-6 engines of the 3-series BMW stand?
how are they regarded in the 6-cyl world?
how are they regarded in the 6-cyl world?
I would rather see larger V6's. When I was a kid I wanted a 5 liter Wankle Engine!!!LOL
So in my mind 4-6 liter is the ideal range for a V6.I would like to see larger I4's too. I like the idea of a 3-3.5 liter I4. The problemis that globaly smaller I4's make more sense!
So in my mind 4-6 liter is the ideal range for a V6.I would like to see larger I4's too. I like the idea of a 3-3.5 liter I4. The problemis that globaly smaller I4's make more sense!
Originally Posted By: BuickGN
Originally Posted By: Camu Mahubah
Most of my experience with V6 engines has come with GM motors and I have found them to be coarse and lackluster when it comes to exhaust sound. Put a nice exhaust on a I-4 and you get a motorcycle like sound which I have always enjoyed.
I have no idea how anyone could prefer an annoying 4 banger with exhaust over a 6 cylinder. The only 4 bangers I think sound decent are the Subaru boxer engines. Give me a Buick turbo V6 any day even over some V8s.
Anyone who has driven a 944S2 knows just how bad idle vibrations can be on a big 4 cylinder. More cylinders make it feel more refined.
I can think of no V8 which sounds worse than the turbo V6 in a similar state of tune of course. Even the flat-heads sound awesome with the right exhaust and tuning. The best sounding V6 ever in existence has to be this one. That V6 has much more R&D than any General Motors push-rod V6 from the eighties.
Originally Posted By: Camu Mahubah
Most of my experience with V6 engines has come with GM motors and I have found them to be coarse and lackluster when it comes to exhaust sound. Put a nice exhaust on a I-4 and you get a motorcycle like sound which I have always enjoyed.
I have no idea how anyone could prefer an annoying 4 banger with exhaust over a 6 cylinder. The only 4 bangers I think sound decent are the Subaru boxer engines. Give me a Buick turbo V6 any day even over some V8s.
Anyone who has driven a 944S2 knows just how bad idle vibrations can be on a big 4 cylinder. More cylinders make it feel more refined.
I can think of no V8 which sounds worse than the turbo V6 in a similar state of tune of course. Even the flat-heads sound awesome with the right exhaust and tuning. The best sounding V6 ever in existence has to be this one. That V6 has much more R&D than any General Motors push-rod V6 from the eighties.
Originally Posted By: 97tbird
so where do the I-6 engines of the 3-series BMW stand?
how are they regarded in the 6-cyl world?
The 3-liter turbo (335i) was named International Engine of the Year in 2007:
http://en.wikipedia.org/wiki/International_Engine_of_the_Year
It's also on Ward's 10 Best Engines list, but so are Toyota, Nissan, Honda, and GM V6 engines:
http://en.wikipedia.org/wiki/Ward's_10_Best_Engines
so where do the I-6 engines of the 3-series BMW stand?
how are they regarded in the 6-cyl world?
The 3-liter turbo (335i) was named International Engine of the Year in 2007:
http://en.wikipedia.org/wiki/International_Engine_of_the_Year
It's also on Ward's 10 Best Engines list, but so are Toyota, Nissan, Honda, and GM V6 engines:
http://en.wikipedia.org/wiki/Ward's_10_Best_Engines
I know I will probably get some flack for this, but Ford's Duratec 3.0L isa nice engine in my opinion. Drove a Ford Fusion with it and was sweetly surprised.
I had a couple of cars with Ford's 2.5L Duratec V6. It was on the Ward's 10 best list for a year or two.
This engine has nothing to do with Mazda's 2.5L V6.
This engine has nothing to do with Mazda's 2.5L V6.
Horsepower is a bogus measurement of power. Torque, especially at lower rpms is a much more useful measurement. Torque is what accelerates you, horsepower is what gives top speed. Since you rarely drive at top speed, but you accelerate every time you drive, torque is the better measurement of an engines "drive-ability". The newer engines boasting high horsepower numbers have to scream up to or near redline to achieve it, and are usually dogs from a stop.
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