Best engine for a hypermiler Z

[rxKaffee]

What models/years were available in the us with the RWD SR20DE?

 

The s13 crowd are also using FWD sr20's with minor modifications, to power RWD drivetrains. There's also the SR16VE/SR20VE that is supposed to get awesome fuel economy and power.

 

If you're looking for something this small though, I would probably go with an rb20. It'll no doubt be cheaper(well, I was thinking in comparison for sr20det when I typed that part). Many parts interchange with USDM engines, so there's not a whole lot of worry of maintenance parts importing. The valvetrain of ca and rb series are far superior to sr(with possible exception of the srXXve's complex variable valvetrain).

 

There are two versions of the L-series(the engine that comes in Z), with 2.0L displacement that should be nearly "dropin". A 4cyl L20, and a 6cyl L20. The 4cyl L20 also comes in a diesel and turbo diesel model.

 

The overseas VG engines came in a 2.0L option for a bit. I'm not sure if this was avail for the DOHC models, or strictly limited to SOHC. State side DOHC vg's had some variable cam stuff that should help fuel economy a bit.

[Daeron]

The RX7 presents interesting situations because of the relative height of the stock engine versus anything else. Also, I may well be mistaken, but I always thought the 2nd gen were kinda heavy..??

 

 

He DOES have an interesting point, and I have lost track at this point... but how married to the S30 concept are you? If you DO want to stick with an S30, then you need to start boning up on how to set the thing up aerodynamically, and there is no time like the present. the Aero sub-forum is a result of a group day done at a wind tunnel facility last summer, and MUCH data was gathered regarding different pieces and body kits used, and not all of it was at all intuitive.

 

 

On the other hand...

 

If *I* were to build my dream econo-sportster it would be either a CRX (sorry I like em anyhow) or really.. the REAL dream ecobox would be a Subaru XT.

 

 

Specifically, a FWD, NA, 4 cyl, 1.8 liter 2+2, 2 door sports car, shaped like a wedge, with a drag coefficient of 0.29. Reports of this engine in a five speed, FWD sedan or wagon getting mileage of up to 40 mpg are considered reliable, reports of up to 50 are heard but usually the skeptics are skeptical of anything over 40. I haven't heard anyone say "*I* have a FWD 5 speed NA XT!! It gets such and such MPG city/highway!" yet. Everyone hears "Subaru" and thinks of AWD or 4WD but back in the 80's and before, the best selling point in many peoples opinions was economy. The NA 1.8s were usually all TBI; but the XTs actually came with a SPFI "spider" manifold and I *think* different cylinder heads but not substantially so. ALL of the vehicles that I refer to with above economy reports were TBI, or weber carburetors. It is an economy motor, 89hp/108tq IIRC. There WERE turbo 4's and an NA 6 cylinder, based on the same engine. You could get AWD in the car, some of them came stock with a problematic (but easy to swap out and not entirely difficult to repair, just $$) computer controlled air suspension....

 

Sorry, I have to make the full case for this car, since I have already started. Thus far I've talked about "economy Z motor," which is one subject that simply comes up ALOT in my family.. but this is MY "dream MPG sportscar," so now that I've started I'm just going to finish and let it sit

 

So.. I don't know how easy it would be to put onto the XT, but the sedans and such were made with manual steering, so a manual rack for the car exists. 0.29 drag coefficient. An MPFI intake system exists, albeit with 1984 technology. Computer controlled Air suspension exists on some models, but is probably more trouble than it could be worth to fool with. Car weighs about 2500 pounds or so, weight CAN be shed. Engine in less aerodynamic vehicles, at about the same weight, with stock factory TBI and electronic ignition (nice, simple, easy to maintain hitachi stuff) achieves ~40 mpg or BETTER. Non-interference, 9.5:1 compression, run on low test stock, big bore, short stroke, torque-heavy, MPFI, megasquirted, SOHC 1.8 liter boxer four. In a vehcile that weighs 2200-2500 pounds, with a drag of 0.29. You could even swap out, say, a newer EJ18, and retain the stock transmission with use of a readily available adapter plate... I could go on............

 

wiki on the XT

 

allright, I am done.

[rxKaffee]

The RX7 presents interesting situations because of the relative height of the stock engine versus anything else. Also, I may well be mistaken, but I always thought the 2nd gen were kinda heavy..??

There are some kits for bolting in Buick 3.8's. And tons of people put in sbc/lsX engines, so they find some way to make it work. A fully loaded GXL or turboII model should "only" be about 2700 to 2800lbs. Ditch the leather and fancy doodads and it goes down pretty quick. Swap rear seats for storage bins, get rid of the solid composite underbumper, etc. Cheap lexan hatch glass works wonders. With a partially stripped interior my GXL was getting about 22mpg mixed on stock ecu running in limp mode with the O2 sensor disconnected. Rear gear choices are a little limited I believe, but there's a bit of choice.

 

the Aero sub-forum is a result of a group day done at a wind tunnel facility last summer, and MUCH data was gathered regarding different pieces and body kits used, and not all of it was at all intuitive.

Semi OT here... but I didn't see any ZX data in the Aero section. Am I just overlooking it, or am I SOL with my s130 and aero data?

[Daeron]

Semi OT here... but I didn't see any ZX data in the Aero section. Am I just overlooking it, or am I SOL with my s130 and aero data?

I stand corrected regarding all the RX7 stuff. As far as S130 aero yah, the only vehicles involved in the test day were S30s. There was only so much of a research project that could be tackled via volunteer committee, doing TWO chassis was too much. However, if you take some time to look at the differences that differently shaped pieces made on the S30, alot can be intuited at your own risk..

[Gollum]

You're not SOL by having a 280ZX... quite the contrary. You'll be hard pressed to find someone that doesn't believe the S130 is more aerodynamic. It just is. As a base care nissan designed it to be MUCH more aerodynamic and they did a pretty good job. Here's some key differences between the two that help the S130 substantially:

 

Lowered front hood line and brought the bumper down, forcing more air over the car, not under.

 

Blocked off more frontal area to make better use of air cooling and reducing drag.

 

Raked back windshield and added more curvature/radius.

 

If you just dealt with the lift the back makes (add some Vortex generators and a mild spoiler) you'd have a very stable high speed car. Perform more duct work for the front and design a belly pan and some headlight covers and you're good to go.

 

Back on topic though:

 

I'm not sure I'd recommend the RB20 simply because of weight. If you're economy concious every pound is going to help. Converting all the glass to lexan would give you quite an increase of milage all on it's own.

 

As it's been briefly touched on here, the whole package will be crucial if your goals are to be maximized. Suspension, aero, drivetrain, rigidity, etc should all be looked at if you want to squeeze the most out of the car.

[boodlefoof]

I've been considering building a super-high-mileage machine quite a bit for the past five or six years. Now, with gas prices going up... I've been thinking about it more and more.

 

The basic concept is to take the lightest possible platform and put in an already efficient engine.

 

So, my thought process has taken me to something like a Mini or Audi 500 or 600 (all of which weigh around 1400 pounds or less). The nice thing about these is also that they are old enough (1960s) to be easily modified without running into problems with emissions laws (at least here in VA). They aren't the most aerodynamic possibilities, so I am open to other recommendations for possibilities. In stock form, these will put down 40-50mpg.

 

Then, I would plug in either an efficient motorcycle engine and gearbox or possibly the D15Z1 engine from a mid-90s Civic VX. The motorcycle engine combo would probably shed some weight (a nice plus), but these engines weren't really made to pull 1400 pounds and therefore might be overburdened. The VX engine is a nice possibility because it already gets 50mpg highway while pulling a 2300 pound Honda. It is certainly up to the task and would probably see a bit of a mileage improvement with close to a thousand fewer pounds to pull.

[silver280zx]

Put an Ld28 in it, then remove as much wieght as possible.

http://video.google.com/videoplay?docid=-4560231195287690993&q=ld28&ei=y8tSSO_QHoGqrQKrw_DCDA

 

I have an ae86 corolla, and i thought about making it fully electric. My Z is only a toy right now, so im daily driving an 83 mazda B2200 diesel pickup, on my last tank of diesel, I got 44mpg, with full interior running the ac every now and again. Imagine what kind of milage a lieghter car will get with a diesel. The Ld28 maximas supposidly get around 30mpg, they could get better if you put it in a lieghter body, and coupled efi and a fuel management possibly. Also in my mazda, I run biodiesel. The only modifications needed for biodiesel is really synthetic fuel lines.

[rudypoochris]

Here is some food for thought on this thread... Source:

 

http://autos.yahoo.com/articles/autos_content_landing_pages/579/6-ways-youre-wasting-gas;_ylc=X3oDMTE3YjFtdXFhBF9TAzI3MTYxNDkEc2VjA2ZwLXRvZGF5BHNsawN3YXN0aW5nLWdhcw--

 

Quote:

 

Idling, meanwhile, burns about a half-mile worth of gas every minute, according to the California Energy Commission.

 

I have thought this for a long time. This is a HUGE impact in my opinion. It is like going 30mph for free, but you are stationary. Obviously "half-mile worth of gas every minute" is a vague term with no speed listed, but it is interesting none the less.

[seanof30306]

Here is some food for thought on this thread... Source:

 

http://autos.yahoo.com/articles/autos_content_landing_pages/579/6-ways-youre-wasting-gas;_ylc=X3oDMTE3YjFtdXFhBF9TAzI3MTYxNDkEc2VjA2ZwLXRvZGF5BHNsawN3YXN0aW5nLWdhcw--

 

Quote:

 

I have thought this for a long time. This is a HUGE impact in my opinion. It is like going 30mph for free, but you are stationary. Obviously "half-mile worth of gas every minute" is a vague term with no speed listed, but it is interesting none the less.

 

That's why hypermilers shut the car off at stoplights, etc. It make a difference. The ideal hypermiler has a button on the steering wheel to interrupt the ignition (without turning off the PCM), and a start button on the shifter so you can shut the car off and start it back up again without having to take your hands off the wheel and shifter. An Eco-version of HOTAS.

 

To address a few other things that have popped up here in the past few weeks:

 

Get a CRX, etc: The truth is, the simplest way to achieve the 40+ mpg goal would be to get a really solid CRX for 3-4 grand. The guys doing the B18 swap all yank out the HF 1.5 litre motor, and transaxle with the really tall 5th gear, so they're abundant, cheap, and a direct bolt in.

 

The thing is, I don't want a CRX, I want a Z-Car.

 

I've been doing research for an LS2 swap into a 240Z for over a year and a half. I've read every thread on LSx swaps on here. Not once, in all those threads, did I see anyone telling the people wanting to do the swap that they can pick up '98 and newer Camaros and Firebirds with LS1s all day long for 3-4 grand, that they can pick up 2002 SS Camaros, the best of the line, for 5-6 grand, and any one of them will have ABS brakes, cruise control, etc., too.

 

Anyone who wants to do that swap already knows it would be easier and cheaper to just buy a Camaro or Firebird. People wanting to swap to a Ford 5.0, or 4.6 already know it would be easier and cheaper to just buy a Mustang.

 

The thing is, they want a Z-Car

 

So do I.

 

About four years ago, I lined up against a 240Z at the drag strip. I clicked off a 12.90, and he smoked me on the big end. I was pretty suprised. I walked over to his car after the run, and was blown away to learn all he had in it was a 280ZX turbo I6 and a 5 speed. He said all he'd done to it was a cam and injector swap, put on an upgraded turbo, and done some tuning. Like me, he was on street tires, and he'd driven the car over 100 miles to the track!

 

The point is, if you can get that kind of power out of an I6 that is a direct bolt-in, it makes no logical sense to swap to a V8, SR20DET, etc. The reason people do it is because they want to personalize their cars and do something unique with them.

 

What I don't get is, why no one feels the need to point out that glaring logic to those swappers, but so many people seem determined to piss on mine.

 

I don't want a CRX as my hypermiler, I want a Z-Car.

 

Get a Miata, and don't give me that crap about not fitting: I have been living in this body all my life, and am quite capable of determining what I fit into, and what I do not. I've driven a Miata as recently as last week. When you sit in a convertible with the top up, and your head rubs the underside of the top; you do not fit. When you sit in a car, and your legs are smashed against the door and the sides of the console, and actually interfere with your ability to turn the wheel; you do not fit.

 

The bottom line is, regardless of what some know-it-all thinks, I do not fit in a Miata.

 

More importantly, I do not want a Miata, I want a Z-Car.

 

The aerodynamics aren't good, etc.: I currently drive a Jeep Cherokee as my daily driver. It has the drag coefficient of a brick. Anything is an improvement.

 

More importantly, if my only concern was aerodynamics or maximum MPG, I'd get an Insight. I don't want an Insight, though, I want a Z-Car. I will definitely look into doing things to improve the Z-Car's aerodynamics that do not compromise the aesthetics of the car for me, but a Z-Car is what I want.

 

It just blows me away that I would come to an enthusiasts' forum for swapping other engines into Z-Cars and get so much crap about an engine swap I want to do in a Z-Car. It's like going to the N.O.R.M.L. forum and being told smoking pot is bad for you.

 

I sat in my first 240Z in 1973, and fell in love. My best buddy had a beautiful 77 that we spent the late 70s and early 80s going to the discos in, and it was a blast. Every time I've seen a Z-Car since, I've stopped and looked. They've never lost their beauty to me.

 

The only car I like better than a 240Z is a C4 Corvette. The difference is, I fit in a 240Z, and I don't fit in a C4 Corvette. I found I could fabricate new seat brackets and fit pretty well in a 3rd generation Firebird, so that's the way I went at the time, but I have decided I am going to return to my first love with my next project and get an S30. That is what I want.

 

I understand there are cars that already get the gas mileage I want, but, I want a Z-Car.

 

I understand there are cars that have better aerodynamics, but, I want an S30.

 

I just can't understand why so many people feel a need to argue about my choice of cars, the concept of hypermiling, etc. Please, if you have any thoughts on how to accomplish the goal, please share them. if you think the whole idea is BS, then just move on.

[Clifton]

I just can't understand why so many people feel a need to argue about my choice of cars, the concept of hypermiling, etc. Please, if you have any thoughts on how to accomplish the goal, please share them. if you think the whole idea is BS, then just move on.

 

Swapping an LS1 into a light weight Z makes sense. It turns a sporty car into a super car without the super car price. Putting a 80 hp engine that will get 40 mpg into a Z, to people on a board like this, doen't make as much sense as it is costing more to get what's already available.

 

Make it fwd and stick an HF engine in it.

[seanof30306]

Swapping an LS1 into a light weight Z makes sense. It turns a sporty car into a super car without the super car price. Putting a 80 hp engine that will get 40 mpg into a Z, to people on a board like this, doen't make as much sense as it is costing more to get what's already available.

 

Make it fwd and stick an HF engine in it.

 

LS1 Camaros, Firebirds and Corvettes are all readily available, too.

 

Cheap.

 

And they launch at the drag strip.

[Clifton]

LS1 Camaros, Firebirds and Corvettes are all readily available, too.

 

Cheap.

 

And they launch at the drag strip.

 

Ok, so buy a Camaro, have a kinda fast car heavy car and put the HF engine/trans in the Z and have a hypermiler too.

 

You wanted to know why you have resistance, I was just letting you know why. Notice in my previous post I didn't suggest buying another car.

[Daeron]

Don't necessarily lump the 280ZX comments into the category of "you should start out with such and such a car."

 

That is not the intent behind, at least, the more informed people mentioning that point; the intent there is to inform that the aerodynamics on the S130 are superior, and any attempt to emulate the changes made in the S130 revision, onto an S30 chassis should pay off.

 

The fact of the matter is, last summer the do-it-yourself Z-tuning world was blown away by the round of aerodynamic testing that was done on numerous S30 body setups. The impacts of that knowledge are still being felt widespread, and people are pointing those facts out to you. GRANTED, it seems like you are getting more of the "just buy a honda and don't ruin your Z" than the spirit of the place should suggest... but, as I said, don't lose sight of comments that detract from your idea if they point out room for improvement.

 

I still say get a 4 cylinder L-series, and get the extrudabody twin TBI/SU replacement kit. http://www.extrudabody.biz/servlet/the-135/Twin-SU-SU%27s-MGB/Detail

 

$545 for the entire fuel injection hardware, get a MAP and some megasquirt, you should be fuel injected for $1000-$1200.

[HowlerMonkey]

LOL at some weasels making up a new term for something that's been practiced ever since internal combustion vehicles showed up.

 

A RD28Ti in a S130 would be sweet.

[260pos]

My 2 cents

I have a blank canvas. It’s an almost stock late 74 260. It sits in the garage and mocks me, daring me to build a what? I found Sean’s posting on I believe ecomodder.com. I’m pissed at the fuel prices, makes me want to buy a moped, but I like cars better…

My thoughts are a VW tdi swap that I guess would be about 42mpg or 11.9 cents per a mile. A 1.9 liter 4-cyl that should return 35 mpg, or 11.8 cents per a mile. Modify that same motor with high compression and a diet of premium, and an assumed 5% increase in mileage and you get 37 mpg or 11.5 cents per a mile. Kick the compression way up and run e-85 and you will get almost the same mileage as a regular fueled engine, say 34 mpg, but with the subsidized cost it returns 11.4 cents per a mile, but how long is the government is going to pony up with that is anyones guess. Or buy a moped and pay 4.2 cents a mile, no insurance, no registration, but no dates!!! My estimates are conservative on the returns, if you go with high-pressure tires weight reduction, and aero improvements you might me able to hit 40 on premium gas, 50 on diesel.

I figure a Maxima head and cam with flat-tops in my l-26 block with the Maxima injection and l-24 reciprocating ought to get about 32-33 mpg and no fabrication nightmares on premium. 13.2 cents a mile. How many miles do you have to drive to recoup 2 cents? Or say f-it and buy an old Geo, 50mpg easy with the right mods…

Fuel prices were quoted by TropStop;

e-85 $3.899

Reg $4.199

Prem $4.379

Diesel $4.999

[Gollum]

That's CHEAP fuel. I got a STEAL yesterday in the $4.3X range for 87 octane.

 

It seems that with the weight of the S30 cars, you're going to be limited to around 40mpg with the stock aerodynamics, unless you drive 40-45mph everywhere you go. With some well designed aero mods 45-50mpg MIGHT be reachable, but I think serious weight reduction would be needed.

 

And I personally think that 35mpg will be perfectly reachable with a L28ET running on megasquirt on regular 87 octane gas, and be able to dyno over 200hp, so there's power when you need it.

 

It almost begs the question, "why change the motor at all?" The cost of most swaps just isn't worth the increase in MPG in my opinion. The stock motor is good enough to work with. It's like paying more to get a hybrid vehicle. Hybrids are NOT the cheapest cars per mile on the show room floor nowdays. Paying more for better gas mileage isn't always worth it. Same goes for engine swaps.

[seanof30306]

Do you know gas is up over 30 cents a gallon, on average, since I started this thread?

 

How many of us think we'll ever see 2.00 per gallon gas again?

 

How many of us think we'll ever see 3.00 per gallon gas again?

 

There is one car I'd actually prefer to a Z-Car for a hypermiler; a Fiero with an Iron Duke 4 cylinder. The 88 models had the best suspension and brakes, and TBI fuel injection. You can find them all over really cheap, and they really handle well with just a few mods. The non-GT nose in that year looks almost exactly like a C4 Corvettes, and it wouldn't be hard to swap over to the GT rear panels for a great looking car. They're light, and 40 mpg highway isn't uncommon, despite the fact that the iron duke has 2.2 litres displacement. Swapping to a later-model head, some chip burning, and hypermiling driving techniques could easily give 45 mpg.

 

One little problem ........ I don't fit. Not even close.

 

Back to the Eco-Z drawing board.

 

I had a PM from someone who said the L and Z series would bolt up to the standard transmission; that they're essentially the Z-car engine with two cylinders lopped off. That would seem to be a big deal, making a swap pretty easy.

 

I think a 1600 L-series engine with fuel injection ought to do pretty well in a Z-car.

 

I was at the parts store the other day, and started talking to the guy who works there. He has an early-model Miata that he swears he gets 38-40 mpg out of. The old EPA mpg figures were 24/30; the new "recalculated" figures are 21/27. He's getting a lot better than that, and he's not doing any real hypermiling; just driving it easy.

 

If his mileage is real, that 1.6 Miata motor is definitely a candidate. Especially since it's also aluminum, MPFI, and MAF, and mates to a 6 speed transmission. The Miata's GVW was 2700+ lbs, so in a Z-car that weighs 2500 lbs with a cast iron I6, you could be looking at a weight as low as 2200-2300 lbs. Even better for fuel economy.

[seanof30306]

It almost begs the question, "why change the motor at all?" The cost of most swaps just isn't worth the increase in MPG in my opinion. The stock motor is good enough to work with. It's like paying more to get a hybrid vehicle. Hybrids are NOT the cheapest cars per mile on the show room floor nowdays. Paying more for better gas mileage isn't always worth it. Same goes for engine swaps.

 

Why put in an LS1?

 

I saw a barely leaned on 280 ZX turbo run low 12s with street tires a few years back. If i'm not mistaken, that engine/tranny is virtually a direct bolt-in, isn't it? Why go to all the trouble to go to a V*, etc. when you can get the same performance by modding a z-6 cylinder?

 

If it's perfectly acceptable for enthusiasts to swap to another engine entirely in their quest for individualism and a hobby/challenge when their goal is more horsepower, why is it so incomprehensible that someone would want to do it when their goal is mpg?

[Gollum]

Hold on there sean, don't get too excited about weight savings on a motor swap.

 

http://forums.hybridz.org/showthread.php?t=125246

 

Stock L24 crabed motor weighs in at 389.4 with everything on it.

 

Though it's an iron block, these L engines have tiny cylinder heads that are very narrow and short.

 

Only a small percentage of an engine's weight resides in the block. There's a lot of other pieces involved. You can reliably expect up to a 50 pound decrease in weight with some swaps, but don't bet on loosing weight unless you have confirmed weights knowing exactly what was on the motor.

 

Also don't forget that the stock nissan transmission is a feather weight. I believe it's only around 75 pounds, and I've picked them up before and wouldn't have even thought they were that heavy. Most transmissions will be heavier.

[Gollum]

Why put in an LS1?

 

I saw a barely leaned on 280 ZX turbo run low 12s with street tires a few years back. If i'm not mistaken, that engine/tranny is virtually a direct bolt-in, isn't it? Why go to all the trouble to go to a V*, etc. when you can get the same performance by modding a z-6 cylinder?

 

If it's perfectly acceptable for enthusiasts to swap to another engine entirely in their quest for individualism and a hobby/challenge when their goal is more horsepower, why is it so incomprehensible that someone would want to do it when their goal is mpg?

 

Hey, I wasn't bashing you. Sorry if it came across that way.

 

I'm simply stating that if your goal is to save money, then many swaps will fly out the window. I was suggesting doing research into the stock engines. They're low compression from the factory and with todays gas higher compression levels are acceptable, and with modern EFI it'd be perfectly manageable. There's potential in these motors, that's all I'm saying.