Big 4's

"HammerheadFistpunch" (hammerheadfistpunch) 03/06/2018 at 11:52 • Filed to: None

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I like engines on the fringe of normal, Tiny v12's and huge 4 cylinders particularly. This is the Vortec 2900 and its a 2.9 liter I4, which is basically a 3.5 I5 with one less cylinder, which was basically a 4.2 I6 with more bore (and one less cylinder). 185hp and 190 lbs-ft (at a nice low 2800 rpm). Not s particularly smooth engine, but pretty stout.

This is the Toyota 2TR-FE which is still in use in the Tacoma, Land Cruiser Prado (Lexus GX here) and even the 4runner for one model year. 2.7 liters. 164 hp and 181 lbs-ft at a higher 3800 rpm. Toyota also has the 1AR-fe which is only slightly smaller but also 2.7 liters used in the highlander, sienna and RX ~187hp and 186 lbs-ft.

its not just for trucks though, Porsche got in on the action with the 3.0 I4 in the 944 s2. it had 208 hp and 206 lbs-ft.

I know diesel engines go big with their I4', like well over a liter per bucket big, and those are cool too, but this is about big gassers.

BigBlock440 > HammerheadFistpunch 03/06/2018 at 12:21

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That’s not even big when you make it a V8, it’s normal sized. Even a small V8 cut down to 4 cylinders would be considered on the big end of a 4. Wonder if there’s some sort of aspect ratio between displacement per cylinder and total cylinders that has some effect that’s not widely known.

themanwithsauce - has as many vehicles as job titles > HammerheadFistpunch 03/06/2018 at 12:21

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968 Turbo RS. 3.0L turbo inline 4. Porsche has made numerous flat 6 engines with under 3.0L displacement....that 968 was a monster too.

Long-Voyager > HammerheadFistpunch 03/06/2018 at 12:22

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In the days of 1.4L 4 cylinders, I would call Chrysler’s 2.5L SOHC a “big” 4.

HammerheadFistpunch > BigBlock440 03/06/2018 at 12:27

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it is funny like that, that even the HUGE 2.9 I4 is just barely bigger than a 350 SBC. I suspect the trick is balance. If you have better engine balance you can go bigger on the cylinders without making a horrible driving engine. with the Vortec series it was simply an effect of using the ATLAS program so 4.2/6 = .7l/cylinder which made for a 3.5 I5 and a 2.8 I4. Then the 3.5 I5 was found to be a little underpowered so they bumped it up to 3.7 which then meant the I4 got a bump to 2.9. Strange they didn’t bring the I6 to 4.5 liters, but then again it was on its way out, even though it had 291 hp already. At 4.5 liters you would have had well into 310 hp. What a cool base silverado engine that could have been, supplanting the 4.8.   

WilliamsSW > HammerheadFistpunch 03/06/2018 at 12:27

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Pontiac’s 3.2 liter I4 - not so coincidentally, exactly half the displacement of their 389 V8!

WilliamsSW > BigBlock440 03/06/2018 at 12:28

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Ha- you mean like the I4 Pontiac used in the first gen Tempest? :)

HammerheadFistpunch > Long-Voyager 03/06/2018 at 12:29

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same with Nissan. I think the Toyota 2.7 is the current biggest.

InFierority Complex > HammerheadFistpunch 03/06/2018 at 12:30

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Big 4s, you say?

HammerheadFistpunch > InFierority Complex 03/06/2018 at 12:31

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ah yes, the BoT. back when if you needed more speed you just added more engine and built a chassis around that.

LongbowMkII > BigBlock440 03/06/2018 at 12:31

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F1 cars seem to correlate at about 300cc/cyl, at least when they could do things like change cyl counts/layouts

HammerheadFistpunch > LongbowMkII 03/06/2018 at 12:32

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the current trend is 500 cc buckets. makes for a nice square 2.0 I4, 3.0 I6 and 4.0 V8.

Textured Soy Protein > HammerheadFistpunch 03/06/2018 at 12:33

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The Porsche 968 used an updated version of the 944 S2 motor, with VarioCam, and made 236 hp and 225 lb/ft.

Mach-inator > HammerheadFistpunch 03/06/2018 at 12:33

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My father can’t get his head around GM’s 2.8L Diesel 4-cyl. He thinks it would shake itself apart for it being a massive 4-cyl diesel. I have to remind him of commercial truck engines...

HammerheadFistpunch > WilliamsSW 03/06/2018 at 12:34

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I knew about the pontiac, but only included modern ones, still what would a 3.2 I4 drive like. Badly is my guess. Reminds me of the GM twin 6.

well, we got these huge V6's (351 ci) but we need something more...I know! lets put two together for a 702 ci V12!

HammerheadFistpunch > Mach-inator 03/06/2018 at 12:36

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yup, though i have to say its not like big diesel I4's are smooth, per se, but they work. When you don’t have to rev to work, displacement isn’t as big a deal.

e36Jeff now drives a ZHP > BigBlock440 03/06/2018 at 12:44

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It’s because I4's are inherently out of balance and need balance shafts to fix the vibrations(at least for anything that intends to have any kind of revs). The bigger(and heavier) the rotating assembly becomes the bigger the balance shafts need to be. At some point the parasitic drag of the balance shafts becomes larger than the extra friction of adding cylinders, so beyond a certain point it makes no sense to stick with an I4. My guess would be that the limit is somewhere in the 2.5-3.0L range. V8's do not need balance shafts, so they can be as big as you want without shaking themselves to pieces.

WilliamsSW > HammerheadFistpunch 03/06/2018 at 12:45

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Ha - yeah, I figured that engine was just too old to be part of the OP, but I find it pretty interesting anyways. By all accounts I’ve read, it’s not a smooth runner (shocker), and sounds fairly agricultural.

BaT actually has a ‘62 Tempest LeMans convertible listed with that 194 (and a 4 barrel carb!) right now, but no video:

https://bringatrailer.com/listing/1962-pontiac-tempest-lemans-convertible/

LongbowMkII > HammerheadFistpunch 03/06/2018 at 12:46

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yeah, for street cars ~ 500cc is my litmus test. <400cc small, >700cc big, but sub 1.6l engines seem to be popping up a bit.

for F1, particulaly the N/ A days you’d need them to be small so you can spin the snot out of them but still large enough to still flow air optimally/re liably .

WilliamsSW > HammerheadFistpunch 03/06/2018 at 12:46

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And note that they brag about the 275 HP (gross!) from that monster!

BigBlock440 > e36Jeff now drives a ZHP 03/06/2018 at 12:59

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How about 6's? They seem to be on the smaller end of things to, aside from the diesels. Even a 4.3 being a big six, still is only a 5.7 in an 8. Or is it just a factor of V8 sounding better than big V6? Or it’d be too lazy an engine for the size?

functionoverfashion > HammerheadFistpunch 03/06/2018 at 13:13

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I had a boat with a 3.7 liter 4 cylinder. It was actually quite smooth and quiet, and pretty easy on gas for how fast the boat was.

!!! UNKNOWN CONTENT TYPE !!!

The MerCruiser 470 began production in 1976. It was a 3.7-liter inline four-cylinder engine that produced 170 horsepower, a powerful alternative to the 160- and 165-horsepower six-cylinder Mercury engines. The 470 featured a cast aluminum engine block designed by Mercury Marine, the name Kiekhaefer’s company had taken in 1969, and the block was mated with an iron cylinder head from the Ford 460 V-8 engine. The same engine block was used in several other MerCruiser engines, including the 170, 190, 485 and 488.

(source)

HammerheadFistpunch > functionoverfashion 03/06/2018 at 13:36

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We had a boat with the twin 3.0 i4 Mercs. Pretty smooth but fiberglass and water are great vibration dampers

Duck Duck Grey Duck FTMFW! > InFierority Complex 03/06/2018 at 13:48

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This wins.

e36Jeff now drives a ZHP > BigBlock440 03/06/2018 at 13:49

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A V8 is not inherently a lazy engine. The “laziness” of an engine is all about its design, there are plenty of high strung small(er) V8's out there, like the S65 from BMW or the 4.2L Audi V8

The balance issues only apply to V6's, as Inline 6's have pretty good harmonics, their only limiting factor is camshaft whip due to the inherent issues with a long camshaft. V6's do require balance shafts, but the drag issues aren’t as bad as big I4's, and the rotating assembly won’t weigh as much(the weight of a piston increases exponentially with as the bore goes up), so the balance issues aren’t quite as bad.

Also there is an economy of scale going on there as well, as most big V6's(like the 4.3L you mention) are based on cut-down V8's so they get to share common parts like valves, pistons, rocker arms etc so it makes a bit more sense to make it work rather than design a smaller V8.

Additionally many V6's are fitted to places where a V8 wouldn’t fit, namely FWD cars.

functionoverfashion > HammerheadFistpunch 03/06/2018 at 13:51

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Ironically, those aren’t known for being smooth, except at speed. Maybe in a bigger boat, they were better. But they’re not awesome in a 17' sterndrive setup - they were known at the marina as the Shake N Bake. I may have mentioned this here before.

BigBlock440 > e36Jeff now drives a ZHP 03/06/2018 at 14:34

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I didn’t mean the V8's are lazy, but the large V6's would be due to their large displacement. I was thinking the dynamics of a small V8 would be more suited to a car than a V6 of the same size.

e36Jeff now drives a ZHP > BigBlock440 03/06/2018 at 14:55

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There is no particular reason a larger 4.0L+ V6 couldn’t also be high-strung, it just wouldn’t be as good as a V8 of the same size due to the drag of the balance shafts and costs required to overcome engineering challenges, so nobody bothers doing it. The closest I can recall is Nissan/Infinity’s 3.7L.

Saracen > Mach-inator 03/06/2018 at 15:09

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huge balance shafts.

Saracen > HammerheadFistpunch 03/06/2018 at 15:15

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Those big four bangers all need twin balance shafts to smooth out the second-order harmonics. Bit, torquey four cylinders = long stroke = much heavier pistons and connecting rods. Generally anything bigger than 2 liters is difficult to cancel out second order vibrations with only four cylinders.

Kiltedpadre > HammerheadFistpunch 03/06/2018 at 16:47

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For a VERY brief time I had a 3/4ton 1967 GMC that had been special ordered with the 305ci V-6.

HammerheadFistpunch > Kiltedpadre 03/06/2018 at 16:50

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I hear those big 6's are really fun to drive. Just lazy buckets of power.

Kiltedpadre > HammerheadFistpunch 03/06/2018 at 17:25

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I didn’t have it long enough to know.

I bought it off eBay for a couple hundred bucks and sold it before even making it home. Was at a gas station halfway home and was offered 15 times what I’d payed.

HammerheadFistpunch > Kiltedpadre 03/06/2018 at 17:26

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dayum!

gmctavish needs more space > HammerheadFistpunch 03/06/2018 at 18:18

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The Raider has a 2.6 I4 that manages to only make 109hp at the crank

gmporschenut also a fan of hondas > BigBlock440 03/06/2018 at 21:55

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Most v-8s were for max power at low rpms, you can make the cylinders larger and gain power, but you’ll be loosing efficency.

If one is making a small car where efficiency is the #1 goal, then one starts trading off fuel miliage for more power.

Its about getting an ideal cumbustion out of the fuel. In a petrol/gasoline engine the flame can only spread from the spark so fast. About 20 years ago 400cc per cylinder was found to be the best.  

.With advancements in variable timing, fuel injection and then direct enjection, manufactureres were able to get up to 600cc per cylinder.Its the increase in 600cc per cylinder we started seeing in the mid 2000s.

but the widespread adoption of turbos, which want to run at lower rpms, for higher fuel economy the previous advantage of larger cylinders was lost. thus we’re returning to 500 and in some cases 400cc

https://blog.caranddriver.com/why-0-5-liter-cylinders-will-soon-dominate-automotive-engine-design/

Rugged Simplicity > HammerheadFistpunch 03/07/2018 at 23:49

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Would the gentleman like to sample the 1.8L V6?

HammerheadFistpunch > Rugged Simplicity 03/07/2018 at 23:51

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I love the K8!