Efficiency

Wow, I need to troll a bit. This thread is full of fail. It has lots of well-thought posts about turbocharger efficiency and this or that, but it misses the mark for what the OP actually asked. Only a very few of you actually paid attention... those that suggested the KA24E, and those who suggested to just work with the CA20E to make it more efficient.

One of the criteria in the OP was *reliability*, and NO turbocharged engine is reliable unless the turbo is new/rebuilt, and the engine itself is new/rebuilt. Anyone who says otherwise is a crackhead.

Stick with a naturally-aspirated engine. The CA20E is reliable. Given a free-flowing intake and exhaust, and some lightening of the chassis, it's quite peppy. Having seen Sterling's, I was surprised, it gets up and goes vigorously.

Otherwise, Asparagus' breakdown of the cost for a KA24E is spot on. It's a tank of an engine, built for abuse, and decently efficient (at least as good as the CA20E). It also has the added bonus of more power (if only a modest improvement).

COMPLETELY DISREGARD turbocharged engines if you want a reliable setup. And while there may be solid data supporting the idea that a turbo *can* be driven efficiently, chances are more likely you will forget now and then and find yourself dipping a bit into boost accidentally, and so the reality is your gas consumption will be worse than it is at present.

And the VG is a poor choice *for you*, if only because obtaining the proper crossmember isn't such an easy task.

turbos are kind of high maintenance arent they?na is the o.g way.and i didnt even think crossmembers.lol but regardless.if you want to hunt down a vg models crossmember,the vg is the shizzy.

Turbos wear out. Seals go bad, and spill oil into your combustion chambers and into your exhaust system, they can also seize and your car will run too rich (and inefficient, not to mention running rich can kill your cat-converter and your O2 sensor rather quickly). Rebuilding them *properly* isn't cheap, either. Also, the forced induction on the engine places a lot more stress on the head gasket, and engines with a fair amount of miles on them can have head gasket failure, whereas non-turbo engines rarely suffer from head gasket problems.

Turbos are great power adders, but this guy wasn't interested in power, he was interested in gas mileage and reliability. I would place more importance on the latter of the two.

Thanks for your input Arro.

You are the second one to mention Sterling.  I did a search for Sterling but came up empty.  Is there a post that describes all that Sterling did to his CA20?

Also, I noticed that you specified KA24E.  Are you saying that the E is better than the DE?  Earlier I had asked about this difference in regard to my objectives, but I have not gotten any responses.  I know my objectives are a little unusual but I am surprised that it is not a more prominent subject since gas hit $4 for a while.

Out of curiosity, what is the normal lifespan of a turbo?

Btw, even with a non turbo I will probably have the engine rebuilt.  It would seem that it would be necessary for my objectives to be met.

Thanks again.

I think a new/rebuilt stock type turbo is good for about 75,000 miles in an oem situation. A four cylinder new/rebuilt is good for a around 100,000 mi. Some last longer, but with the steeper gears and higher average revs, it's not going to be healthy to far beyond that. The larger the displacement, the less the motor has to spin to get the same abount of work done. So the milage increases accordingly; V6 the V8 in stock unmodded trim could well out last any car it's put in.

As far as an E vs DE; There's about seven different 4 cyl motors mentioned. The KA24E is actually a three valve motor. It's large displacement will give it a longer life I think. The valve train suffers some cause of the additional lobes and valve springs. Also I think this is a timing chain motor, which transfers more crank shaft harmonics to the valve trane.

On the CA the two valve volumetric efficiency is lower than the DET. Also this makes the motor run outta wind quicker. Also if it runs outta wind quicker, it'll teach you to short shift. The lower powerband will keep the bearings and rings longer. Also the 2v has less mass and spring pressure on the cam. A four valve flows more/makes more power.

Also there's hydrolic and solid lifter CA20s. Also the CA18DET has a power valve- this keeps the manifold runner air speed high for improved low and mid ranges.

The SR has chain, not like the belt in the CA. Also it's slightly larger than the CA, It has a better head for power in the early-highport versions, probably in the later to. It has a tappet I think it's called vs the CAde's direct cam on bucket. Also one lobe for two valves vs the CAde's lobe per valve. Keep in mind there's still a sping for each valve- Hey this reminds me of the springless valves in Ducati bikes. Sorry digressing.

Also there's bore to stroke ratios, mass, and shit-pile of other factors. But there's some of my 2cents

Thanks, JonB.  

The life expectancy of a turbo is longer than I expected.

It may be helpful no narrow it down a bit in regard to E vs DE.  It seems that the most highly suggested engine is the KA24 with the CA18 coming behind that.  It seems that you gave me a pretty good picture of the CA18, though it would be nice to know if there is any fuel efficiency differences.  But I don't see any comparisons of the KA E and DE.  You don't really mention the KA DE.  Which is the more durable, reliable engine?  Which will get the better fuel economy?

These are the things I would like to know.

Thanks for what you did give, though.

ArroTurbos wear out. Seals go bad, and spill oil into your combustion chambers and into your exhaust system, they can also seize and your car will run too rich (and inefficient, not to mention running rich can kill your cat-converter and your O2 sensor rather quickly). Rebuilding them *properly* isn't cheap, either. Also, the forced induction on the engine places a lot more stress on the head gasket, and engines with a fair amount of miles on them can have head gasket failure, whereas non-turbo engines rarely suffer from head gasket problems.

Turbos are great power adders, but this guy wasn't interested in power, he was interested in gas mileage and reliability. I would place more importance on the latter of the two.

Everything JonB said assumes a NEW condition turbocharger AND a new condition engine, otherwise my comments stand about turbocharged engine reliability concerns.

Also, there's nothing wrong with timing belt vs. chain. I've had only one belt snap in my life, and that was a Chrysler engine with a LOTTTTTT of miles on it. I've also heard of chains breaking, but again that's uncommon.

Just because the CA18ET is the second most recommended engine in here doesn't mean that it should be a consideration at all. Again I cite reliability issues with used turbocharged engines.

The DE and E are both great engines. The DE will be NEWER and thus will be preferred for longevity and reliability, but otherwise they're both pretty stout.

I am sorry for the confusion.  The question about the two engines KA and CA (E vs DE) was meant to find out not only reliability and durability of each, but also to see if anyone had any experience or knowledge of which would have the better fuel ecconomy (E vs DE).

It was my understanding from the first post in response to my original post that there is a CA18E or CA18DE (no T).  I had responded that I was not aware that these existed.  But that would mean nothing since I am not knowledgeable about these things.  I just had not seen these engines mention on this website.

Nontheless, the purpose of the question was to compare fuel efficiency of E vs DE.  It seems that both engines are reliable and durable. The other criteria in my original post was fuel economy so that is my question regarding the difference in E and DE.  Which would be better at 70-75 mph driving?

Again, sorry for the confusion.

Thanks.

Arro, I see that you have a KA24DE.  What kind of mileage do you get on the highway?

The DE is more modern, and as such will probably be more efficient. I think the differences between the KA24E and the KA24DE fuel efficiency are insignificant. Again, the DE will be newer and thus may be more reliable.

By virtue of the fact that the KA24DE is a dual cam engine with more valves, it makes more power at the same RPM's, so I would imagine it's a more efficient engine than the single cam engine (the KA24E). I think that's what you're asking.

BTW, where are you located?

Thanks, Ju.  It is an interesting read.  I bookmarked it for future research.  

You are right... it is not pretty.... but it is efficient.