4 bangers part II

[Titan]

n8wvi, if you got a good Subaru engine (there were some that were seal leakers...I think those were the 2.0 engine), you can get well over 200000 miles from it, if it's taken care of. My younger brother just sold one at 246,000 miles. Still used 5-30 oil. Still didn't consume oil between changes. He also had a Toyota Previa van, ALSO sold at 246,000 miles (what is is about 240K? He said, a quarter of a million just seems like enough). Still didn't burn, still used 5-30. He just did basic service intervals on both cars, nothing special at all.

 

[heynow]

I think the longevity of an engine has more to do with how well it was designed and how well it is maintained than with its hp/liter rating. A chevy 350 is alot more tolerant of abuse such as less frequent oil changes than a highly tuned turbo engine which would have much higher oil temps and more stress put on it.

 

[bob_ninja]

rpn453 & Christopher,

From time to time we hear of engines that lasted 200K, 300K,...., 1 million miles! They always seem to be bigger engines, 6s and 8s. I don't remember seeing a 4 cylinder 150+ HP engine that lasted 400K miles. Sure everything is possible using appropriate materials. I am more interested in the practical real-world examples.
To put it another way, if one can build a long lasting 4 cylinder engine that can output 150+ HP, then why build more expensive 6 and 8 cylinder engines at all???? (speaking of passanger cars, not industrial applications)
If a van has a 6 cylinder 240HP why not make it cheaper using a 4 cylinder turbo 240HP???

I guess I am asking why turbo and supercharging modules are not used more often. Is it cost? Reliability? What?

 

[OriginHacker21]

I think the American dream has always had a bigger engine. A 4 cylinder just doesn't cut it if you want a powerful engine (sound and all).

Nowdays with high gas prices - I don't mind driving a 4cyl getting almost 40mpg highway. Although, when money permits I plan on getting a big truck with a 10cyl or 8... Just the feeling of having something like that is intoxicating.

Still plan on having a good 4cyl for my daily work drive or what not...


I think bob_ninja is right - of all the engines that make it past 300k - I've never heard of a 4cyl to do the same. I've been told this is because they have a higher RPM.

... My car (2.2L 4cyl 140HP) must be special because at 70mph and 80mph my RPM is -200RPM lower than my friend's 2001 BMW 330ci (225hp? 6cyl). Does this mean my car will last longer?

Even better, my parents Pontiac TransPort 1998 is geared so low? that at 70mph it is around 1,500 RPM! HOWEVER - my parent's 2001 Ford Focus sounds like it is redlining at 10k rpm when I just go 70...

I plan on taking my car to 400,000. That is and has been my dream ever since I got my vehicle

 

[cousincletus]

Only 4 cylinders I have actually seen make it past 300K were both GM, although I'm sure there are others. One was a 2.0 OHV from a Cavalier and the other was an S-10 with the "4-Tech" Iron Duke. Both vehicles were from the mid-1980s.

 

[earthworm]

This is absolutely no sense in using a V8 when a 6 will suffice; the same with the 4 vs the 6.. but in America where gas is cheap, and a few other undeveloped nations as well, one may as well use a V16, as was the case in the 30s.

If this is the case of a V6 vs the turbo 4, as in both Saab and VW,well, I think the jury is still out, even after all this time...

But there is no sense,IMO, in building an engine good for 20 years and a body good for 15..

 

[bar1]

I guess it's difficult to develop a gasoline, 4 cylinder turbo engine, with "no turbo lag", flat torque curve and make it reliable and cheap at the same time.
I've seen 4 cyl. turbo diesel engines reach 300,000 miles (taxis with lots of idle time).

 

[bob_ninja]

Don't know RPM for my 1.6L Civic.
Most other 4cyl machines while cruising 60-70mph are just below half the max RPM.
Mazda Protege and CRV are around 3,500 RPM (max is 8K).
Kawi Ninja bike is around 6K, max is something like 14K I think (don't remember exact number).

Back to the cars, red zone is usually 7-8K and peak HP is usually achieved just below start of red zone, so I am guessing around 6,300 RPM. That means engine is operating around 60% of capacity. Is that high, low or just Ok?

At what RPM are 6s and 8s cruising on highway?

 

[OriginHacker21]

My 4cyl (Pontiac Sunfire 2004) 2.2L 140hp has a red line at 6,500 RPM. At 70MPH I'm at 2,550 RPM and at ~81MPH I hit 3,000 RPM.

I know my parent's Honda Accord (coup) is a 4cyl and it has the same red line 6.5k. As for the RPMs I don't know.

 

[rpn453]

quote:

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Originally posted by bob_ninja:
From time to time we hear of engines that lasted 200K, 300K,...., 1 million miles! They always seem to be bigger engines, 6s and 8s. I don't remember seeing a 4 cylinder 150+ HP engine that lasted 400K miles.

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I agree, but 4 cylinder engines that make 150+ HP haven't been common for very long. High mileage on 4 cylinders isn't uncommon though.

I think a lot of high specific output engines are underdesigned for their power compared to non-performance oriented variants (manufacturer believes full-throttle won't be used as much with 250HP as the same block with 100HP?), and also frequently abused by their owners. The combination gives that type of engine a bad reputation for reliability.

quote:

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Originally posted by bob_ninja:
Sure everything is possible using appropriate materials. I am more interested in the practical real-world examples.
To put it another way, if one can build a long lasting 4 cylinder engine that can output 150+ HP, then why build more expensive 6 and 8 cylinder engines at all???? (speaking of passanger cars, not industrial applications)
If a van has a 6 cylinder 240HP why not make it cheaper using a 4 cylinder turbo 240HP???

I guess I am asking why turbo and supercharging modules are not used more often. Is it cost? Reliability? What?

---

I think it's much cheaper to put in a larger low-tech engine than a small high-tech one, with the added bonus of better driveability since it will have more instant-on torque. A supercharger will give you that too, but unlike a turbocharger it's not an efficient way to do it. Meeting required horsepower levels with a smaller engine really only makes sense where space and weight (or maybe even city fuel economy) are concerns.

GM provides an example of saving money using larger engines: they continue to use larger OHV engines than most of the competition's DOHC engines as a cost saving measure, and I don't disagree as long as the engines don't have problems. Some do have problems, but certainly not because they are OHV designs.

[ March 06, 2006, 05:23 PM: Message edited by: rpn453 ]

 

[bob_ninja]

rpn453,
That makes sense. For car companies it is cheaper to add 2/4 cylinders to a simpler design, then to use a more complex design with turbo/supercharing.
Too bad. I find that even the latest 6/8 cyl engines with piston deactivation while cruising still have much worse efficiency then 4s.
I guess as fuel price keeps going up the economics will change and 4s (turbo/SC) will become more popular.

thanks for the replies all

 

[Quick_lude]

quote:

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Originally posted by 97tbird:
didn't the naturally aspired VTEC 4-banger in the Prelude (98-01) make 195 HP or something? (or am I mistaken?)

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Honda has had a few 100hp/L + engines..
170hp from 1.6L Acura Integra GSR
195hp from 1.8L Integra Type-R
200hp from 2.15L

Prelude
240hp from 2L or 2.2L now - Honda S2000

 

[Titan]

My brother has run 2 4 cylinder engines 246,000 miles. Atlanta traffic conditions. Neither burned oil when sold. 4 cylinders can do the job, for a long time.

Rpm's on my two 4 cylinders are 3000 in the mid-70 range, I believe redline is 6250, don't know for sure. Not really sure % of redline at cruising is a meaningful number, though. If you "overgear" and engine, you generally have more stress on it, because you are lugging it, compared to running the rpms up closer to the power band. Right?

 

[ikeepmychevytoo]

I fail to see the displacement as a sole efficiency point. If efficiency needed I think one should prefer a lighter car, displacement should be cleverly selected for the task like city vs. hwy, mountainous vs. low land, altitude etc.

On my v6, max output is at 4800rpm, which exacts the top speed of 120mph. Accordingly, 2400 rpm is the cruising speed in the midst of the power band and it is exactly where the max torque is gained. While there are also badly designed sixes or eight drivetrains I've yet to see a four to arrange such a clever, easily managable orientation. Turbo fours come close but for some reason they consume more, unless the going is not really steady or it is mostly city milage.

 

[VNT]

I dont know where your getting your info but turbo
charged cars are very dependable and looking back at the 80's vintage turbo Dodges, they produced 146HP 176TQ in early Turbo 1 1984 form, 175HP 200TQ in Turbo 2 form(Added intercooler 1987 Daytona and 1986 Shelby Omni GLHS), 175HP 210TQ in turbo IV form( Variable Nozzle Turbo in Daytonas and Shelby CSX 89/90 vintage, and 224HP 217 TQ in Turbo 3 form( Spirit RT/Daytona IROC RT 16 valve). With a few mods you can easily get 225WHP and 350WTQ and much more depending on your budget. I believe chysler sold over 1.4 million turbo charged cars from 1984-1993.

Now you have the 2.4 in the SRT4 and PT GT stock pushing 270HP and 300TQ stock. The stg kits available can push this over 320WHP 380WTQ. I believe the new Caliber SRT4 will be introduced at 300HP 260TQ. I belive the WRX's and Evos have similiar numbers.

Only disadvantage of engines with hair dryers is you really need to run good oil in them and change it more often. Other than that their isnt much downside. Turbo lag is way over blown especially on the stock versions since the exhaust housings are fairly small so lag is almost non existant. Actually most who hop em up will desire some lag, it is your friend when launching so you dont blow away the tires .

 

[LARKBILL]

I don't know if I would choose those cars as an example of why turbos are good, I don't know about the others out there in mechanic land, but replacing head gaskets on those cars went a long way towards putting my oldest son through his last couple years of college. It's amazing how fast word spreads once a couple people find out someone will moonlight it for less than half the dealer.

 

[VNT]

Larkbill

that is funny, I have 5 of those cars. Earliest HG I ever had to do was at 140K miles. Of couse i can change em in about 60 minutes in fully dressed G-body with AC. Assumes head isnt warped and doesnt need to be removed. They would tend to rot in back corner of # 4 cylinder but usually lasted well past 100K mark.

A friend has a Reliant race car(runs 10.4s at 132MPH), blew a head gasket( running 32 PSI) at Atco when I was there and changed it with a little help in about 15 minutes

Head gaskets were not a mjor issue assuming poeple didnt over heat them, ie maybe changed the coolant and thermostat once in a while and if the radiator got tired replaced it. Rads would get the red dead metal on the cooling fins after about 5 or so years.

http://www.thedodgegarage.com/the_reliant_2000.html

 

[carock]

It has always been my theory that engines can only tolerate so much heat per square inch of piston area. So the greater load the engine operates at, the sooner it will fail. I learned this hot rodding turbo charged engines, where the pistons get hot and the ring lands fail.This is a common failure mechanism in well maintained engines and there is no way to fight it. Over time the ring lands get hammered to a larger gap and the piston ring starts to fail. The hotter the piston runs the sooner this happens. So "all things being equal" the four cyclinder engines wear out sooner because the pistons run hotter.

 

[OriginHacker21]

OFF TOPIC:
So, if I get this right - take a long uphill, it is easier for the engine to run for 10 minutes:

at 4,500 rpm in 4th gear with 78% load @ 70mph
or at 2,600 in 5th gear at 95% load @ 70mph?

On Topic:

A lot of GM's older 4cyls were the OHV design I believe. Nowadays 2003+ a lot of the newer cars come with the 2.2L Ecotec Dohc 140HP (Sunfire, Cobalt, Solistice, Impala, etc...).

Just comparing how the engines sound the new 2.2L Dohc sounds much better in comparison to the older 2.2L OHV. I've seen several OHV's die at 120k even though they were taken care of (3k OCIs). Also read online of people taking the new 2.2l very far mileage wise.

 

[VNT]

If it aint lean it aint mean

Actully most people run EGT guages. At cruise in part throttle boost I may hit 1400 degrees. You might melt stuff at 1600, depends on where you mount the probe. I run an EGT in # 4 cylinder exh runner in the manifold. Leanest cylinder in a 2.2/2.5 dodge.

Detonation is what cracks ring lands and that usually happens if you run too much boost or you get a bad batch of gas and run on the hairy edge.

I have GLHS Stg 2 electronics on my 86. when you hit about 12 PSI at WOT, you can watch the EGT guage drop from about 1500 to 1375 as the puter opens the injectors, the extra fuel drops the temps which then rise as the boost rises. As long as you have enough fuel and adequate octane you wont waste the pistons. Of course forged pistons are the way to go since they are more robust and cna tolerate more abuse.

In stock form the cals in the computers are very conservative, limit the boost and dump a lot of extra fuel to prevent these problems. That is why in stock form they live long lives. In most cases versus a non turbod engine they are stouter since the OEm puts better parts like SS valves, forged cranks, stouter rods, oil squirters, etc to improve longetivity.

quote:

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Originally posted by carock:
It has always been my theory that engines can only tolerate so much heat per square inch of piston area. So the greater load the engine operates at, the sooner it will fail. I learned this hot rodding turbo charged engines, where the pistons get hot and the ring lands fail.This is a common failure mechanism in well maintained engines and there is no way to fight it. Over time the ring lands get hammered to a larger gap and the piston ring starts to fail. The hotter the piston runs the sooner this happens. So "all things being equal" the four cyclinder engines wear out sooner because the pistons run hotter.

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