Best engine for a hypermiler Z

[Gollum]

Long stroke for the torque?

 

My only experience with aftermarket EFI is systems for American V8s; Accel DFI, F.A.S.T., etc.

 

The issue with those is expense; a bare minimum of 3 grand. Are the better aftermarket EFIs appropriate for this project that expensive?

 

Wow, I wouldn't ever pay that much for an EFI system, unless my engine was worth 15k.

 

Megasquirt can be done for less than 1k easily, and it has been done for that much or less time and time again. You can buy the newest version of the ECU already built for $450, which costs quite a bit more than building it yourself. You won't spend $550 on the remaining parts needed.

[johnc]

The quote above and what was being repsonded to are adding politics/morals into this thread and that's something we don't allow on this site. This is a good thread and has a lot of valuable tech in it. There's no need to add moral judgements about people's "world views" or pontificate on the fate of mankind. Keep it focused on the tech.

[johnc]

clearly, you have a lot of experience with fabrication and S30s in general (that super lightweight front suspension upgrade is AMAZING!) and swapping in SR20DETs. Where would you weigh in on what the best choice for an Eco-Z might be?

 

VW TDI diesel 4 cylinder. You can get 50 mpg+ out of an engine that's puts out 300+ ft. lbs. of torque.

 

http://www.tdiclub.com/

[Daeron]

You want this thread closed and tossed into the Tool Shed?

 

Sorry; I tried to keep it short, but I'm a long winded guy. In retrospect I guess I could have blunted the comment substantially without losing the impact I was going for. I stand corrected.

[seanof30306]

VW TDI diesel 4 cylinder. You can get 50 mpg+ out of an engine that's puts out 300+ ft. lbs. of torque.

 

http://www.tdiclub.com/

 

My main problem with diesel is the price differential. Right now in Tulsa, for example, 87 octane regular is 3.69 per gal. Diesel is 4.39 per gal.

 

So, if you get 50 mpg out of your diesel, your cost per mile at 4.39 per gal is 8.8 cents per mile.

 

If you got only 42 mpg out of your gas powered car, your cost per mile at 3.69 per gal is 8.8 cents per mile.

 

In years gone by, diesel was cheaper than gasoline. It's now more expensive largely due to 3 factors, which will likely cause the price differential to grow even greater

 

1) Sulfur requirements. Since the government began requiring deisel to have less sulfur, the additional refining required and lower yield per processed barrel of crude has caused the price to go up. Sulfur requirements are scheduled to continue to adjust downward over the next several years, which should cause the price to rise even more.

 

2) Refining capacity. No new refineries have been built in this country in 30 years. Diesel refining capacity has been maxed out for most of that time. As people buy more deisel-powered cars, the demand for diesel should go up, and so therefore should the price.

 

3) Heating oil demands. Over the past several years, heating oil has experienced increased popularity in new construction in colder climates, which is causing more competition for the same fuel oil used to refine diesel fuel, home heating oil, and jet fuel.

 

A lot of guys will mention bio diesel, and it is a relevant choice. I have a neighbor who goes around to restaurants, gets the used fryer oil they normally have to pay to have removed, and runs it in his deisel pickup. The thing is, if this takes off, it'll only be a matter of time before entrepeneurs begin to pay restaurants for their used cooking oil and begin selling it. Get enough of those entrepeneurs together, and you've got a lobby. A lobby that could esily make the point to our wonderful elected representatives that those bio fuels are untaxed.

 

It's not an unreasonable outcome to see it made illegal to process your own biofuel in the future. Even if it's not, it's entirely reasonable to expect to see the free fuel source go away as entrepeneurs put the restaurants on contract.

 

Then there's the environmental issues. Even with the new soot filters, diesels burn a lot dirtier, and my idea of an Eco-Z would be one that puts out less emissions than it used to, not more.

 

My personal opinion is that ethanol is the future for IC engines. While I'm 100% against the corn ethanol program we're currently on, cellulose ethanol is on the horizon, and I believe it's the answer. I'd want my Eco-Z to be able to run on ethanol, if that is the way it goes.

 

Now, I know there are plenty of opinions on this stuff, and I'm not suggesting I'm right, and anyone else is wrong. I'm only putting this in to explain the reasoning behind my choices, for my project. If that's inappropriate, just let me know and I'll take it out.

 

So, the ultimate point is, I want to stay with a gasoline engine for my Eco-Z.

 

John, with that caveat, what would your recommendation be? Also, since you've done the SR20DET swap, what do you think specifically about an SR20DE?

[OlderThanMe]

VW TDI diesel 4 cylinder. You can get 50 mpg+ out of an engine that's puts out 300+ ft. lbs. of torque.

 

John, with that caveat, what would your recommendation be? Also, since you've done the SR20DET swap, what do you think specifically about an SR20DE?

 

Did you not freaking see the part about 50MPG AND 300+ Ft. lbs of torque?

There is almost no way a Z will get 42mpg with a < 2 liter gasoline motor and still be fun to drive.

I'd do the VW TDI as well or a CA18DET and live with 25-35mpg.

 

How many Z guys here care about the enviroment anyway? I mean there are guys with huge gas hog turbo V8's that get .02mpg and they do it because they can. I'm not shooting your idea down, but just look at reality here. You aren't going to make a 50mpg gas powered first gen Z and be able to use it for what the Z was meant for, having FUN.

 

Sure you can work on the aero to reduce drag, add Honda Insight tires, strip the interior out, and probably get 50mpg... but what do you have then? A freak of a car that is trying to be something that it is not.

 

Look at this page with the Hybrid Z motto for what this site is here for...

 

No note of staying green or saving the enviroment.

 

Also nobody has seriously thought about considerably changing their driving habits. Not just being light on the throttle, but using the pulse and glide method. Drive up the hills and then coast down.

 

I have gotten higher MPG than the EPA rating in my 100% stock 2004 Frontier crew cab with the VG33(heavy beast). I normally averaged 19mpg which is in the middle of the 17-21mpg(before-10% ethanol gas) range given by the EPA. Lately I have been experimenting with better driving technique and have gotten up to 22mpg even with the ethanol mix. Before the switch over to 10% ethanol I got up to 23.5mpg over a whole tank. It also helps to make peak torque at 2200RPMs and never need to go above 2600RPMs except on the highway where the good 5th gear makes ~20mpg at 70mph and ~19MPG at 80mph but with aerodynamics like a big red brick.

 

Heck, I got 17mpg out of my N/A L6 SU'd Z and I was just driving around normally which means shifting at 3500-4000RPMs and moderate throttle use. I gained about 2mpg after going to decently stiff coilovers, illuminas, and freshening up all of the U-joints/diff mount just from less suspension/driveline takeup losses. I also didn't have to use as much throttle to get the car moving...

 

GnoseZ here has a 3.2 Rebello stroker with tripple weber 45's and he told me that he gets 28mpg on the highway. It probably goes down to like 10mpg or less under heavy foot situations but heck, that is efficient on the highway!

[seanof30306]

I'm sorry my decision as to what I want to do with a Z offends you, but it is my decision, not yours.

 

If you don't like it; if it somehow offends your sensibilities that someone is interested in hybridizing a Z for efficiency, rather than horsepower, then I'd suggest you don't follow this particular thread, as it will only further enrage you.

 

Also, I'm sorry you don't like my decision to stay with a gasoline powered engine, but, that is my decision.

 

If you don't like it; if it somehow offends your sensibilities that I choose to run a gasoline powered engine, rather than a diesel, then I'd suggest you don't follow this particular thread, as it will only further enrage you.

 

Thank you.

 

That said, I am looking for discussion and advice on how one might build a hybrid Z to get 40 mpg, with a gasoline-fueled engine.

 

I figured hybridz.org was the best place to discuss that. Go figure.

[RedEvilrps13]

is it wrong that when i see the word hypermiler, i think you're trying to get good gas mileage out of like...the Millenium Falcon or a TIE fighter....

 

why not just get a miata? sporty, and gets good gas mileage, no engine swap needed!

 

and dont give me that "im too tall for one" bull, im 6'3 and i fit in one comfortably, and my 6'7 friend fits in one as well.

[seanof30306]

is it wrong that when i see the word hypermiler, i think you're trying to get good gas mileage out of like...the Millenium Falcon or a TIE fighter....

 

why not just get a miata? sporty, and gets good gas mileage, no engine swap needed!

 

and dont give me that "im too tall for one" bull, im 6'3 and i fit in one comfortably, and my 6'7 friend fits in one as well.

 

Why not get a Corvette or a Camaro instead of swapping an LSX into an S30?

 

And the whole point is to feel like you're strapping into a TIE fighter, to get excited when you walk across the parking lot to the car, to love the way the car looks when you drive down a street and see it in reflective plate glass windows .... AND get mileage close to what you could get driving a clapped out econobox.

 

It's having your cake, and eating it, too.

[proxlamus©]

Strip everything out of the car, make the car as light as you can, swap in a Honda Civic motor and be careful on the gas lol.

[seanof30306]

A couple of questions:

 

Earlier, someone mentioned "L" and "Z" series engines. What are they?

 

In trying to learn more about the SR20DE, I came across a reference to an SR20DEe, the "e" referring to "LEV". I think that is an economy version of the SR20DE, but I can't find anything more about it, and don't know what "LEV" means.

 

Does anyone know more?

[Gollum]

LEV = Low emition vehicle I believe.

 

The L engines are the stock inline 6 motors the car came with, and the similar designed 4 cylinders in the 510 and other datsuns.

 

The Z engine is a 4 cylinder with similar blocks to the L series but has a crossflow head. HP outputs were pretty low in the 80-100ish range.

 

Sean - Don't worry about the people complaining about being a bit "green". Just don't try to convince us we should all be a bit greener (which you havn't thus far) and we'll all be fine. If the origonal creators of this site were able to welcome in the other V8 swaps, turbo inline 4 and 6 swaps and the other exotic swaps, then I think we collectively should be able to accept that someone wants to put a low output engine in their car to get good gas milage.

 

One thing that I think you should consider about the TDI motor though, is that it can get 50mpg in today's cars. In a much lighter Z I see no reason it shouldn't see better gas milage like any other motor we've been talking about. So sure diesel is expensive but let's keep it real. 60mpg with the right tune and driving might be seen out of this swap. You want to keep it gasoline that's fine with me though.

 

Oh, and personally I think the LSx motors nearly IS the swap that allows you to "have your cake and eat it to". There are guys getting 400+wheel hp that still manage 25mpg with very spirited freeway driving seeing 80mph+ average speeds. It's not unheard of to see 30mpg out of a LSx powered Z.

 

Seeing what gas milage the LSx swaps are getting it seems that there MUST be some modern gasonline engine capable of 50+mpg in a Z with reasonable power when you want it.

[seanof30306]

Oh, and personally I think the LSx motors nearly IS the swap that allows you to "have your cake and eat it to". There are guys getting 400+wheel hp that still manage 25mpg with very spirited freeway driving seeing 80mph+ average speeds. It's not unheard of to see 30mpg out of a LSx powered Z.

 

Seeing what gas milage the LSx swaps are getting it seems that there MUST be some modern gasonline engine capable of 50+mpg in a Z with reasonable power when you want it.

 

The LSx IS amazing. I don't think there's any other engine that delivers that much power, with that much economy, especially at the price you can get it at.

 

More specifically, the LSx head is amazing. I originally had a set of ported iron Vortec heads on my Firebird's 383 Gen I small block. After a lot of tuning, I got it to 367 RWHP, and got a best of 26mpg on the highway, all on 87 octane. For a TBI, that is VERY good.

 

When AFR came out with their Eliminator, with LSx style combustion chambers, I grabbed a set and spent six months tuning to take advantage of their amazing airflow. So far, I've gotten 402 RWHP, with a torque band as broad and flat as Texas, and a best of 30 hwy MPG. A full tank of mixed driving (without putting my foot in it), is good for 22-23 mpg. That combustion chamber design makes a ton more power, and allowed me to go a lot leaner on my part-throttle fuel tables.

 

The thing is, I believe we're only going to see gas go up and up, and while the mileage I'm getting is very good for what it is, it's not good enough, especially when you consider the fact that my Firebird decreases in value, and the potential buyers' market for it grows smaller with every increase in the price of gas.

 

My plan is to get ahead of the curve, selling the Firebird while I can still get a decent price for it, and getting into eco-modding before the prices get too high. I could well be wrong, but I've gone as far as I can go with my Firebird, anyway (without an engine change, or induction/FI change), so it's time to look for another project. If I'm wrong, and the gas situation changes dramatically in the future, I can alway pull the 4 banger out and stuff an LSx in, so it's not that big a deal to go in this direction.

[rxKaffee]

I too have been looking for a slightly more modern replacement for my L28E, which would give me similar or better power, and improved fuel economy.

 

I thought about going cheap, and getting a 350 vortec engine from one of the pre-2000 chevy trucks. T56, gear the rear for low rpms, utilize the engine's torque. But then I realised I'd want light rockers, and roller "everythings". So the cheapo 350 idea quickly became not so cheap. Also more weight than I really "want" to have up there. They claim 30mpg in automatic Caprices, so I figure with some gearing, an economy cam, a manual tranny you could do pretty decent.

 

A Buick 3800 series II is a little bit more expensive engine than an oldschool 350 with truck heads. Less weight. Could still get enough torque out of one of these to use a really low rpm rear gear for fuel economy.

 

Why not look at a CNG powered engine? They get slightly less fuel economy than a gasser, but the fuel is DIRT cheap. CNG seems to have "similar" qualities to E85 in terms of power, torque, knock resistance and mpg. You could take your i6 L engine, bump the compression with some aftermarket pistons or shave the head, maybe touch up the quench areas a bit, and run it on some of this cheap fuel that is already being delivered to your home. Most CNG conversions can switch back to gas easily in any parkinglot that you stop at, but most of them don't expect bumped compression either...

 

Honda actually has a CNG engine from the factory now, it looked to get better mpg than some other similar displacement gas engines. I wonder what all they do to tailor it to CNG.

 

Over on zdriver, there's a few guys with tuned up L28 getting something like 30mpg city. By tuned up, I don't mean an L28ET with a turbo the size of a badger, putting out 400hp though

 

I'm currently thinking of an LD28 for my Z. I'm leaning towards this one mostly because it should "almost" drop right in(oil pan is only fab that I know of being necessary). Being old indirect injection, pre-chamber design, it should beable to use WVO without too much fuss, but I've not looked indepth at this. I read somewhere that the LD has a couple organic gaskets/seals that do not like the WVO. They supposedly get 40mpg(pump diesel) highway in a 5spd maxima from the early 80s. Most claim only about 23-25mpg city on stock engines with the automatic 3spd in a maxima though. Using L28ET manifolds is supposed to improve fuel economy and power a bit as well. People are seeing these bad boys to 385ft-lbs(@ 2200rpm) on stock internals.

 

In addition to Honda, Nissan has some 4banger lean-burn engines now as well. There's one in some of the Sentras, that also has a loooong stroke that makes pretty good torque for an economy 4banger. GQ Series or something I believe... I always get the Nissan i4 letters mixed up though.

[twoeightythreez]

(quote)I agree on the brakes. On a non-power brake/power-steering car, though, there's nothing at all wrong or dangerous with the auto-stop technique. I do it all the time on my bike and it is 100% safe(quote)

 

It's perfectly safe with power brakes too, as long as you know that the brake pedal effort goes way up...you can still stop the car.

 

 

(quote)As far as lean-tuning, that can get very dangerous. You can lean an engine well past Stoich, and it'll run great on a flat road, but run into even a slight uphill, or romp on the gas by accident or in an emergency, and you can find yourself with catastrophic detonation (quote)

 

Get yourself a megasquirt and lean out all the high-KPA maps. Using this tecnique I had my 280z getting 30mpg highway with no other modifications, at about 90mph. It ran really lean on the flats but if you tune it right it'll richen right up as soon as it sees load.

 

I've been fooling around with my GM TBI Firebird for a number of years. The forum I belong to has an avid group of tuners who have long-since hacked the ECM's and began burning their own chips. In the past several years, we've moved beyond chip burning to emulators, wideband, and on the fly tuning. My TBI originally had 3 fuel maps; it now has 24, and more timing tables than you can shake a stick at. Recently, a couple of guys have gotten greedy, taking their "economy modes" into the stratosphere, and they've done a lot of damage. Even though they have multiple tables, those 20 year old OBD1 ecm's just aren't agile enough to react in time when you rolling along at 19:1 and hit a hill

 

You don't need 25 maps. Just program the ONE map for both economy and performance. The "switch" for your ecu becomes your FOOT, like it always was.

[twoeightythreez]

I too have been looking for a slightly more modern replacement for my L28E, which would give me similar or better power, and improved fuel economy.

 

I thought about going cheap, and getting a 350 vortec engine from one of the pre-2000 chevy trucks. T56, gear the rear for low rpms, utilize the engine's torque. But then I realised I'd want light rockers, and roller "everythings". So the cheapo 350 idea quickly became not so cheap. Also more weight than I really "want" to have up there. They claim 30mpg in automatic Caprices, so I figure with some gearing, an economy cam, a manual tranny you could do pretty decent.

 

A Buick 3800 series II is a little bit more expensive engine than an oldschool 350 with truck heads. Less weight. Could still get enough torque out of one of these to use a really low rpm rear gear for fuel economy.

 

Why not look at a CNG powered engine? They get slightly less fuel economy than a gasser, but the fuel is DIRT cheap. CNG seems to have "similar" qualities to E85 in terms of power, torque, knock resistance and mpg. You could take your i6 L engine, bump the compression with some aftermarket pistons or shave the head, maybe touch up the quench areas a bit, and run it on some of this cheap fuel that is already being delivered to your home. Most CNG conversions can switch back to gas easily in any parkinglot that you stop at, but most of them don't expect bumped compression either...

 

Honda actually has a CNG engine from the factory now, it looked to get better mpg than some other similar displacement gas engines. I wonder what all they do to tailor it to CNG.

 

Over on zdriver, there's a few guys with tuned up L28 getting something like 30mpg city. By tuned up, I don't mean an L28ET with a turbo the size of a badger, putting out 400hp though

 

I'm currently thinking of an LD28 for my Z. I'm leaning towards this one mostly because it should "almost" drop right in(oil pan is only fab that I know of being necessary). Being old indirect injection, pre-chamber design, it should beable to use WVO without too much fuss, but I've not looked indepth at this. I read somewhere that the LD has a couple organic gaskets/seals that do not like the WVO. They supposedly get 40mpg(pump diesel) highway in a 5spd maxima from the early 80s. Most claim only about 23-25mpg city on stock engines with the automatic 3spd in a maxima though. Using L28ET manifolds is supposed to improve fuel economy and power a bit as well. People are seeing these bad boys to 385ft-lbs(@ 2200rpm) on stock internals.

 

In addition to Honda, Nissan has some 4banger lean-burn engines now as well. There's one in some of the Sentras, that also has a loooong stroke that makes pretty good torque for an economy 4banger. GQ Series or something I believe... I always get the Nissan i4 letters mixed up though.

 

Why not just get an economy car and build the Z you want to build?

My 1990 sentra (GA16i, TBI, 4speed) gets 30mpg if you beat the piss out of it. And, unlike most civics, no offense intended but it's true, hondas have useless peaky powerbands that try to advertise high peak horsepower per displacement, my sentra actually can get out it's own way without being driven like it was stolen.

(it may only have 98hp but it has 102lb/ft from idle to redline...the shifter is almost superflous once you're doing 15mph)

[twoeightythreez]

Wow, I wouldn't ever pay that much for an EFI system, unless my engine was worth 15k.

 

Megasquirt can be done for less than 1k easily, and it has been done for that much or less time and time again. You can buy the newest version of the ECU already built for $450, which costs quite a bit more than building it yourself. You won't spend $550 on the remaining parts needed.

 

Couldn't agree more. And a Megasquirt will allow you to tune for gas mileage and power....on the same map. I still don't understand why people are so obsessed with "switchable" ECU's....tune it right and you don't need to switch it....if your right foot wants fuel economy, keep the engine in the low load/high KPA maps or the high load/low KPA maps and you'll get good economy.

 

If your right foot wants power, put the engine somewhere in between those two extremes and if it's tuned right you'll get the maximum power.

[seanof30306]

Why not just get an economy car and build the Z you want to build?

 

Because I want to build a Z to be an economy car.

 

If you don't agree with that, it's certainly your right, but, that is my choice.

 

If you have some advice or opinions on how to achieve that, I would love to hear them.

 

I'm not interested, however, in having to defend whether I should do it, or not, which economy cars I should buy, instead, etc. What I'm interested in exploring is ways to achieve the goal I've set.

[(goldfish)]

The long stroke should give more time for a more complete burning of the gas. Better gas milage for the power.

[rxKaffee]

Because I want to build a Z to be an economy car.

 

Are you dead set on the Z its self, or more interested in this type of "80's fastback sport" styling? Or just after a cheap sporty Nissan chassis? Would a ZX fit your tastes? I'm not sure how significant, but the aerodynamics of the ZX are a bit better. If your desire is just this style, I'd suggest a 2nd gen RX7 chassis as a starting point. They have almost as low of Coefficient of Drag as a CRX.