Efficiency

I have a 1984 200SX notchback CA20E.  I am looking at doing an engine swap, but my goals are different from what I have seen expressed as I have read around the web site.  I want a car that is the most efficient it can be.  By efficiency I am talking about gas mileage as well and durability and dependability. Therefore, I am looking for cost efficient and fuel efficient.

The CA20E was great when the speed limit was 55 mph.  But since the engine lacks much power, the mpgs drop dramatically after 55 mph.  Is there an engine that will have a little more power that will get better gas mileage than the present engine?  Would it also be a dependable and durable engine?  

I am looking at restoring my car to be as "like new" as possible.  I don't necessarily mean like "stock".  I mean that it will be completely ready to perform like a new car which only needs basic maintenance to keep it going.  I want to do body work and interior to the same end.

I had read somewhere that the turbos (CA18ET) of that same year actually had more power and better gas mileage than the CA20's.  That is what sparked my interest in swapping engines.  If what I read is true, it would seem that either the CA18ET or the CA18DET would be good candidates for my car.  But I wanted to see what you more knowledgeable ones have to say about this.

Thanks for any help and guidance you can give me.

If you want something that doesn't need a lot of maintenance, try to stay with a non-turbo engine. A sr20de will be a nice choice I believe, or a ca18de wich you can get almost every parts from any nissan dealer.

Ca18det was never offered in america (correct me if I'm wrong on this) and some parts will need to be imported from europe or japan.

Thanks bigjer.

Would a CA18DE have more power than the CA20?  I had not even seen that engine mentioned in the threads I have read.  Was it in a 180SX?

Do you (or anyone else) know what the CA18DE and/or SR20DE do in gas mileage?

I would recommend the ka24e or de. It's so readily available, cheap, easy to swap, decent gas mileage and it's a tank. I have friends who average higher than 25mpg

if im not mistaken, a turbo engine will be more efficient then a non turbo since it uses exhaust gases to make power and in a sense can get more mpg per hp then a non turbo.

either way, any CA engine is a bolt in afair, and all you really need to do is the wiring. swapping a SR into the s12 is a lil more complicated, but nothing that requires more then simple handtools. the real issue is gonna be keeping your foot light on the pedal once you become addicted to turbo surges as its alot of fun lol. id suggest a special type of boost controller that only spools hard when u stomp on the gas, that way you can drive normally and save fuel till you wanna have a lil fun, then u step on it and the boost goes up. its quite cool

julieif im not mistaken, a turbo engine will be more efficient then a non turbo since it uses exhaust gases to make power and in a sense can get more mpg per hp then a non turbo.

either way, any CA engine is a bolt in afair, and all you really need to do is the wiring. swapping a SR into the s12 is a lil more complicated, but nothing that requires more then simple handtools. the real issue is gonna be keeping your foot light on the pedal once you become addicted to turbo surges as its alot of fun lol

yes, but the turbo also recycles the byproduct of the burned up gas and translates it into power, which the NA engine would let go to waste. as you said, it comes down to setup and such. i think the deciding factor for the thread author will be costs and ease of install, as he doesnt seem too concerned with power and more with a cheap daily driver

he's looking for fuel efficiency, not engine efficiency.

e. If you wanna talk about engine efficiency, we could talk about rotaries all day.

I would say for a daily driver setup and not as an aggressive of a tune, that a turbo setup would have the edge on efficiency.  I see this as the reason why many small engines that use less petrol on average than a bigger block can produce a good amount of power without the automatic assumption/use of petrol.  I would almost say that VTec would be a better ideal to work with honestly.

Come on guys. ka24e

engine set costs like 200 bucks with trans
easy swap
cheap
readily available
25+ mpg
super reliable

it even has some grunt

I havent seen a KA with 25+mpg.  But then again, that's me and the area i'm around.  Most KAs get low 20s and most are ditched.

My single cam STOCK buddies get 25mpg all day everyday, I'm pretty jealous. But I mean, people are almost giving these engine sets away. So why beat around the bush? Keep it in shape and it's the whole shabang

But doesnt engine efficiency also lead to petrol usage in non aggressive tuned applications?  I'm talking more about daily driver every day styled motor setups.

Where are you going with this? I'm already talking about non agressiveness, I'm talking about stock. haha

asparagusMy single cam STOCK buddies get 25mpg all day everyday, I'm pretty jealous. But I mean, people are almost giving these engine sets away. So why beat around the bush? Keep it in shape and it's the whole shabang

asparagusWhere are you going with this? I'm already talking about non agressiveness, I'm talking about stock. haha

Thanks for your input Asparagus and Julie.

Going a little further then.  If I went non turbo, what set up would increase efficiency?  It is my understanding that not much can be done for gas mileage except maybe a change in exhaust.  If so, what would be the recommendations for each of the suggested engines (CA18DE, SR20DE, KA24E)

From Julie's suggestion, what is the best set up for a turbo CA engine for efficiency.  Julie, what you described is right on as far is my ideal is concerned.  Can you be more specific about the boost controller (name or whatever)?

Btw, Julie, you don't have to worry about a lead foot here.  When the car was new I got 45 mpg on the road even though the car was rated at something like 38 mpg.

With regard to bigjer's comments about maintenance of turbo, how much more maintenance does a turbo normally require?  I don't mind a little maintenance here and there.  But I don't want a continual headache!

Thanks again.

KA's definitely get between 25-28

CA's might get better mpg just due to the obvious displacement difference 600cc's give or take

Well I mean, by keeping it shape, I simply meant things like making sure you have enough oil in it and parts that aren't broken. Stuff like EGR check engine lights will actually cause the engine to run richer, etc etc etc. Things like that should be kept in check, but that applies to every engine right? If it works like it's supposed to, it's "the whole shabang"

But if the vg30 is getting upwards of 30mpg, that sounds like a definite option too. But it would require a vg crossmember

For an NA engine I would suggest you keep it well maintained as far as tuning.  Maybe play with the timing just a bit to help accommodate the stock rich setting the factory tends to put on the car.  Intake and exhaust and such.  Maybe a MAF but depends on what engine you are running with and the following ECU with it if it is applicable.

asparagusBut if the vg30 is getting upwards of 30mpg, that sounds like a definite option too. But it would require a vg crossmember

Thanks to you, too, Draconis.  I really do appreciate the discussion.  I am listening.

My SR with out the turbo ran 25MPG, with the turbo it gets 28MPG. And I have a pretty heavy right foot.

seishuku, that is good information, too.  Thanks

Just for the engine;
 Volumetric, thermal, and mechanical efficiencies, the real one- BSFC(Brake Specific Fuel Consumtion)How much every HP costs you in gas.

Volumetric is pretty much the horse power- You can get more outta a motor with it but its gonna take more fuel.

Mechanical is the friction in the motor- A factor but not an end-all of the best motor.

Thermal I'd have to say is the biggest effect on the BSFC, and one of the hardest and one of the most expensive to improve. Won't get you the most power, but will get you more power for the gas you put in it. Nothin you can do to break records compared to the auto makers efforts though, but they are governed by accountants. I'd bet the newer the motor, the better the motor.

You'll probaly need to be as specific as possible with what you want.

 We could hook you up with the largest-slowest spinning 4 we could find.  It'll have more torque than the rest, less throttle movement to get the car going, and spin slower= less mechanical wear on the motor and last forever. How about a 2.5  2-valve with an Iron head? Then we get the pistons and some other internals thermal coated! Put a taller gear and chuck as much weight off the car as possible. Little thermal loss-Iron head. Two valves run by a belt=little mechanical loss. Small cam duration matched to the torque of the motor. Hell we could get ya cruisin at 65mph at 2.2k and over 35mpg. Just messin!

Also like Julie says. Decient turbo setup. Day to day grind it's almost never on boost. A little loss in flow efficiency from the turbo down low. But when you summon the boost, It's crams the freakin' air in there, and the gas to. You can lean on the turbo from time to time and maybee even pull more mpg than a non-turbo. But I think it's really up to how you drive. Mash on it all the time, I highly doubt you'll ever get better gas milage.

 There's alotta good minds on this site, Much better than me, dig deeper/be more specific maybee the Ideas will flow in.

I'd look at the out-put of the motors stock, with the MPG of their original cars. Keeping in mind the weight of the vehicals vs your car's weight and don't forget torque and where in the power band the torque and hp is at and how and where you drive.

From there getting better than stock is gonna take some money and research. Less restrictive exhaust, coatings and things. Get weight outta the car, Maybee swap the gears, (I spin at 3k at 55-60, real bad for highway mpg). Lighter wheels are a certain factor, things like that.

Actually Julie is on to something there about the turbo. When people think turbo, immediately they think "power adder". Well yes, it does that, but could also be used to increase fuel efficiency. Much of the automakers are relooking at using turbos to improve performance out of smaller displacement engines compared to larger naturally aspirated ones. Just they are not tuned to output a rediculus amount of boost.

Prime example: Ford's EcoBoost GTDI engines
http://www.autobloggreen.com/2008/01/06/de...injection-engi/

However from a practicality standpoint with the current offerings made available to ya. It would probably more effort than one would be willing to spend to get the setup right. So if your really just looking for something to drop in without much fuss or hassle, my post is pretty much moot. However if you don't mind the heresy, you find an engine from another manufacture! Just trying to convert a B16 to a RWD layout might be a PITA

why not look at your ca that you already have,
 1. cold air intake
 2. cat-back exhaust
 3. new, more effecient O2 sensor
 4. better plugs, wires
If the question is effeciency, by letting the engine breathe easier and look at the ratios betters. that should do what your looking for. other engines are better, Im using the CA18DET, but its really up to you and what your looking for as in HP vs MPG.
thats just my 2cts

my ca-det gets about 400 miles to a tank..thats about 32mpg

That's dang good for a CA18DET.  My RB20 had high 20s like 27-29 until I started playing with it... Then it dropped to 19-24.

i posted this in a different thread, but its more relevant to this one.
read away...
http://www.importtuner.com/tech/0711_impp_...ency/index.html

large vehicles such as rigs and buses use turbo diesel engines for a reason and thats gas effciency. its literally a "no waste" principal where you try to maximize every resource you can from an engine in order to increase useable power without harming how far you can go with each gallon of fuel.

now, menassy17, take a look at this link. it details a setup utilized back in the day by turbo omnis and such

http://www.gusmahon.org/html/boostcontrol.htm

blue streakwhy not look at your ca that you already have,
 1. cold air intake
 2. cat-back exhaust
 3. new, more effecient O2 sensor
 4. better plugs, wires
If the question is effeciency, by letting the engine breathe easier and look at the ratios betters. that should do what your looking for. other engines are better, Im using the CA18DET, but its really up to you and what your looking for as in HP vs MPG.
thats just my 2cts

a turbo engine is better then a non turbo

if you're not in boost you can get like from 25 - 30 MPG on a turbo or more (correct me if i'm wrong)

but if you mash that pedal it'll drop.

IMO a KA24E is better.

yeah Tire pressure can get neglected very easily and if your in a climate that can swing quite a bit, you'll have to check your pressure more often. I had to re-adjust my tire pressure here in Tx because from hot to cold real quick, which played with my tire pressure.
Also, make sure your O2 sensor is working in the right order, since that has a direct effect on how much fuel your car will be squirting into the combustion chamber.

blue streakwhy not look at your ca that you already have,
 1. cold air intake
 2. cat-back exhaust
 3. new, more effecient O2 sensor
 4. better plugs, wires
If the question is effeciency, by letting the engine breathe easier and look at the ratios betters. that should do what your looking for. other engines are better, Im using the CA18DET, but its really up to you and what your looking for as in HP vs MPG.
thats just my 2cts

jeffwins24a turbo engine is better then a non turbo

if you're not in boost you can get like from 25 - 30 MPG on a turbo or more (correct me if i'm wrong)

but if you mash that pedal it'll drop.

IMO a KA24E is better.

for what its worth i've had a couple dual cam ka's one of which was a 95 auto s14 which regularly got 29mpg.

Ca18et or ka24e

I personally have both and actually prefer the ka24e in my 240sx. Smoother engine and still gets great gas mileage. I'm still on the same tank from two weeks ago. I've been almost all over the Inland Empire the last two weeks.

Hmmm  Lots of information.  No surprise that some is conflicting, but it all helps to weigh the issues.

There is so much here, I can't address it all, but I do want to keep the communication open so I can learn more.

Btw, I do apologize for my ignorance.  I am 50 years old and have only had two cars in my life.  Both have been excellent cars and I still have them both.  The 1962 Chevy II was my parents' first car and it was passed to me through two sisters and a brother (my younger brother never got it!). The Nissan was my first and only new car.  It has been an excellent car and I have had to do little to it through the years other than normal maintenance. Though I have done much work on the Chevy II (in my younger years).  I have not been able to keep up with car mechanics in my "working" adulthood.

But as you can see... I am inclined toward longevity.

I can't remember who said what right now, and I am not sure that I have remembered everything in proper context so please be understanding if I have misunderstood what has been said.

Someone mentioned that I needed to be more specific about what I want.  I probably assumed too much in my initial post.  In regard to fuel economy I am focusing in on highway mpg.  City mpg is nice, but most of my local driving is done on a scooter.  I have one that can go 80 mph and at 55 and 65 mph gets close to 80 mpg.  My other scooter can go 100 mph and at 70-75 mph gets around 60 mpg.

Obviously, there are times when you just need a car... especially on longer trips.  I have a car and I want it to be as efficient as possible at 70-75 mpg.  Depending on how it affects other things, I would not mind having the little extra punch of power that has been mentioned for situations that may call for such (emergencies, getting out of someone's way, etc.).  For example, if a turbo engine can get better mileage at the same time of giving that "emergency power"... that is a great plus!

There is some truth to someone's statement that, to a point, more power means better gas mileage.  For example, I had a 150cc scooter that could go 60 mph., but when it was going that fast it was at full throttle so my 200cc scooter would get much better gas mileage at 60 mph than the 150cc scooter would.  I know it is not that simple, but it seems to apply in this situation.  My CA20E engine does great on fuel efficiency up until about 60 mph, but falls quickly thereafter.

I do also have some questions:

If a true cold intake is not in the engine compartment, where is it?
Btw, there are no inspections where I live.  

In regard to the exhaust, is there no need for a mod to the exhaust manifold?

Thank you to the two who gave the urls.  Those were very helpful.  Actually, the one on fuel efficiency has potential, but hopefully the next installment will give the specific modifications that will help fuel efficiency.  Do you know when that will be available?  I looked but did not see a date on the one that I read.

Garrett76zt, as I look at your info I see that your KA's are DET. What have you done to get good gas mileage?

Thanks to all.

once a car is moving, it needs less fuel to make power at higher speeds, thats simple physics.

a cold air intake is an aftermarket part, where the air filter is close to the ground, behind the bumper cover and infront of the wheel, typically. they draw in cold air from outside the car, unlike the typical intake that draws in warmer air from the engine bay

exhaust manifolds are iffy. since you understand v8s and such then you surely know how much of an effect of swapping to a full length tubular header on a v8 engine. improved flow improves upper rpm power (i think) but the majority of nissan engines have free flowing manifolds that dont really require mods unless youre searching for those few extra ponies

If you have no inspections, make your cold air directly to the front of your car.  Something like what Signal Auto did with their R34.  It would be interesting to see what you can do.



Best idea in my opinion... do an intake, exhaust and maybe some head work if you can afford it.  Nissan is known for poor flowing of air supply.  Honda's have always had the upper hand when it came to that.  SO by doing that, you will see quite a bit of difference.  Also, play with the throttle cable just a bit to get a good balance for power a little faster so you dont spend so much time playing with the throttle to get off the ground.  Talk to Sterling.  He has made a CA20 act like nothing I've known.  It was a mixture of a couple things here and there and lightening the car where it didnt need the excess parts.  Basically, make it so the engine can breathe better will help you reap rewards.

I would go for a bigger diameter catback exhaust & high flow cat. Exhaust manifold upgrades for these small engines probably wouldn't help much. Exhaust manifold upgrade for a forced induced engine would help some in lag/turbo response.

Remember though that with exhaust modifications, the car/engine is going to be louder and I'm not sure if you'd appreciate the louder noise for long trips.

Try a K&N drop-in filter if you do not want to modify the intake in anyway and in my opinion it's just almost as effective as a cold air intake.

If you want efficiency, you are using the wrong fuel. Gasoline engines produce too much heat, diesel converts much more of its energy into mechanical energy, hence they run colder.

As for the turbo vs non turbo debate, its simple physics really, x amount of CFM require y amount of lbs/hour of fuel. You need to maintain a stoich mixture, however if you can get away with running a small displacement turbo charged motor with compression tipping towards the higher end of the scale, your gains will be much more noticeable than say... A high compression small displacement non turbo motor.

And for the record, my RB25det does about 17mpg. Ow.

And just to add to the conversation pot, what are people's opinions of variable compression engines? Saab was developping one that could accept almost any type of fuel and could vary its compression ratio through a fairly substantial range.

http://en.wikipedia.org/wiki/Saab_Variable...pression_engine

-Dan

RB25sx - SLPRIf you want efficiency, you are using the wrong fuel. Gasoline engines produce too much heat, diesel converts much more of its energy into mechanical energy, hence they run colder.

As for the turbo vs non turbo debate, its simple physics really, x amount of CFM require y amount of lbs/hour of fuel. You need to maintain a stoich mixture, however if you can get away with running a small displacement turbo charged motor with compression tipping towards the higher end of the scale, your gains will be much more noticeable than say... A high compression small displacement non turbo motor.

And for the record, my RB25det does about 17mpg. Ow.

And just to add to the conversation pot, what are people's opinions of variable compression engines? Saab was developping one that could accept almost any type of fuel and could vary its compression ratio through a fairly substantial range.

http://en.wikipedia.org/wiki/Saab_Variable...pression_engine

-Dan

Thanks for the answers.

More questions:

Am I correct in assuming that if I go turbo, I will have to also go with high octane gas?  If I understand what I have read correctly the KA24 is a high compression engine.  It, too, would need high octane (even non turbo), correct?

In regard to the cold air intake, this would not be useful if turbo is applied would it?  It seems that the turbo would introduce hot air that would negate the cold air from the intake.

Concerning the type of fuel, I realize that gasoline is not the most efficient fuel source, but I am not interested in diesel.  However, I do find the idea of water for fuel intriguing.

Thanks again.

Reading back over the thread I realized that I had more questions/responses.

Is there any knowledge of a difference in fuel efficiency between a DE and an E engine?  It seems that having two cams would cause more friction.  I know that in and of itself it could make a difference, but I also know that the engines don't run on such a simplified plane either.

WankelMonkey, I am not stuck on having a Nissan engine.  I am open to any suggestions that would best fit my need.  I have even done a little checking into rotary engines, but it seems that they are not low maintenance nor do they get great gas mileage.  I would love to have a rotary car, but it would not serve my desires in regard to this car.

cold air intakes arent required on a turbo setup because they use something called a "intercooler" which is a small air to air radiator mounted between the turbo and intake manifold.

Another question that has come to me has to do with suspension.  My 200SX has a solid rear axle. If I do a swap will I have to change the suspension?  Is changing the suspension a hard modification?  I will have a 1985 200SX available for parts.  I think it will have the independent suspension so I think I will have the necessary parts available, but I am not sure if it is necessary, possible or even desirable.

its possible but extremely difficult and not really worth it. the type of rear end isnt really as important as its shock and spring combo. a new engine isnt gonna effect the rear end as a whole, but its gonna affect the diff and the tires. so, install better shocks and springs, and better tires and youll be in business. that particular rear end is good up to like... 280hp so youll be ok

we have been working on an info thread regarding the solid rear ends, so take a look. it might help with more of your rear suspension questions

http://www.club-s12.org/forums/index.php?s...c=21752&hl=

KA's really arent high compression, especially ka24e's

boost shouldnt really be a problem, just use 93 octane

the vg is bullet proof,and i speak from experience.mines gone through some shit and has literally outlasted the car itself.lol

nismologistthe vg is bullet proof,and i speak from experience.mines gone through some shit and has literally outlasted the car itself.lol

i would go straight for the ka24e. bullit proof as long as you keep the timing chain and tensioners up to date. and you can get them way cheaper than the ka24de.

either that, or spend a little more money for a ka24de, or if you want a turbo, go for the ca18det

edit:

and i agree that the vg30e is an awesome motor. gobs of torque, feels very fast for a stock motor, revs smooth as a babies ass, gets very decent mpg, dependable (once you work out all of the possible gremlins, and yes theres a lot)

but i would try to stay away from the v6 as a swap, just because its harder to work with than a 4 clyinder, just not as simple. a 4 banger just makes everything cheaper and easier. takes up less space in the bay, and so on