Best engine for a hypermiler Z

[Gollum]

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.

 

 

You kinda answered yourself later in this post. It's all about the ECU you're running. You can only run as lean as it can get you quickly back to safe ratios once you're under load again.

 

I started hypermiling my WRX last week and quit today.

 

Normally I drive like a bat out of hell, on boost, passing and cruising at 5000rpms just to hear the boxer. I get around 23mpg. This past tank I went easy, low revs, no passing, no racing....I grannied over to the gas station at lunch time and got 25.3mpg. Screw it. I'm going back to lead foot. Look out!

 

Gotta love modern turbo cars. It's amazing how lean they actually run in full boost without ping issues. The WRX EMS is amazing though. I'm not sure if the WRX is the same as the STI, but I simply can't believe anything OEM is so advanced after working with it. How many ECUs have datalog ability built in able to measure all sensory systems (rpm, knock, narrow band, boost, etc).

 

 

I don't know about most of you guys, but I find it much more entertaining and fun to find ways to modify my car to get better MPG, not driving habbits. Sure slowing down can gain you significantly better effiency, but who wants to drive 50mph when you're traveling 500+ miles? I'd much rather improve my aerodynamics so what I used to get at 50mph I can now get at 65mph and drive 65mph with a grin on my face.

[Pete84]

Plus, you can't always drive slow. I was on I-40 going from Vegas to Albuquerque, and I was actually kinda scared at times. There was a vicious cross wind, blowing the semis all over the place.

And those trucks were doing 75-80. No way in heck I would let one pass me, the trailors were everywhere. I needed to get to Denver, and there was a storm on the way, so no stopping.

 

So, I can't really imagine going ~55mph on an interstate, even in good weather. Too dangerous.

[Armand]

"Hypermilerring" (man we should really stop using that word lol) is really great. Me and my brother have started doing it and it's great. Most of us live a hustle 'n bustle kinda life and are always in a rush to get from point A to point B. Driving 55mph on the freeway really slows down life, and driving becomes much, much more relaxing. My brother 03 Mini Cooper S went from 27mpg to nearly 40mpg! This tank he's running now is gonna be a record breaker, he's driven over 200 miles with a little more than half a tank left on a 12 gallon tank.

[Clifton]

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.

 

 

You wouldn't tune it to be lean under all conditions, just cruise. No different than tunning an engine to be stoich at cruise. Under load you add fuel.

[nando280zxt]

Doesn't a turbo charger help gas mileage as long as the engine is not under boost?

[johnc]

Doesn't a turbo charger help gas mileage as long as the engine is not under boost?

 

Doubtful. In that situation you are hauling aorund the extra weight of the turbo and associated plumbing. When the turbo isn't providing boost, its just extra weight. What a turbo does do is allow a smaller displacement engine to operate, under acceleration, the same as a large displacement engine.

 

Under load, a turbocharged engine most likely consumes the same amount of fuel as a large displacement engine that produces the same horsepower. The fuel saving advantage of a turbo charged engine comes when the engine is not under load (80% of most driving on the street). Then the engine is operating as a small displalcement engine with a little bit of extra weight (the turbo) to haul around. For most light load/cruise a small displacement engine works just fine.

[Clifton]

Doesn't a turbo charger help gas mileage as long as the engine is not under boost?

 

It is a restriction in the exhaust. Big restriction with a stock T3. Even off boost mileage would be worst.

[seanof30306]

Id just like to say that turning of your bikes engine while you are still riding it so that you can coast is extremely dangerous and no one should ever do it. Bikes need to be able to accelerate to remain stable and it is especially important to be able to roll on the throttle to put weight on the rear wheel in a turn. If you needed to get out of the way of a car or turn quickly you would be in a world of hurt. Proper throttle control and steering will get you out of more situations than the brakes in a car, but this is 10x more true on a bike. I doubt the safety of doing this in a car, but doing it on a bike is a recipe for disaster.

 

 

Sorry I had to chime in on the safety issue here. Ive been riding a long time so ask me how I know. I agree that driving techniques are a huge factor in obtaining good fuel economy but you should not sacrifice safety. Focus instead on aerodynamics, weight, and a good engine choice.

 

Hold on, dude. That is getting a little shrill.

 

I've been riding since I was 15 years old. Everything from motocross to road racing. In virtually every situation in which someone driving for economy would find himself shutting off the engine in order to save gas, there is absolutely no danger is auto-stopping.

 

Sure, if you want to roll up on a 70 degree+ turn at 80 mph, it'd be dangerous to go into that corner with the engine dead (although anyone who doesn't have sissy stripes on his tires could handle it), but hypermilers drive slowly. for the most part. The situations where they auto stop are entirely different.

 

More importantly, the technique is called "auto stop" for a reason. Here's a typical auto stop situation: I'm driving down a surface street at 35 mph. 200 yards ahead of me, a light goes red, so I pull in the clutch and shut off the engine, coasting up to the light. Absolutely, positively nothing unsafe about it.

 

Here's another scenario. I'm driving to work in the slow lane on a multi-lane highway at 60 mph (speed limit 65). I crest the long hill leading up to my 15 degree exit. I check my mirrors to make sure no one is following closely, pull the clutch in, shut the engine off and coast down the hill. By the time I reach the exit, I'm at 55. I continue to coast up to the long red light and sit there, with the engine off, till it goes green. Absolutely nothing unsafe about it.

 

I totally agree that hypermiling can be dangerous if done improperly. I was horrified when the guy who showed me the techniques ran a red light and took a 90 degree corner at 45 mph just because he hates kinetic braking loss. Later the guy pulled his Insight within 3 feet of an 18-wheeler's trailer, shut the engine off and drafted down the highway, proud as he could be!

 

You can't compare every performance enthusiast on this site to the few extremists who go out and tear up the roads. You can't compare every motorcyclist to the manic who rides a wheelie down the highway at 80mph. Don't compare every hypermiler with the few extremists who take it to an unsafe extreme.

[Six_Shooter]

I started hypermiling my WRX last week and quit today.

 

Normally I drive like a bat out of hell, on boost, passing and cruising at 5000rpms just to hear the boxer. I get around 23mpg. This past tank I went easy, low revs, no passing, no racing....I grannied over to the gas station at lunch time and got 25.3mpg. Screw it. I'm going back to lead foot. Look out!

 

Similar result here, I've been trying some techniques with my Malibu to reduce fuel consumption, and although I have not gone through a full tank yet, using these consumption usage techniques, I'm not seeing muchg of an improvment if any, according to the fuel gauge. I have been driving the Z for the last few days anyway.

 

I would think it's one of those learned things, where the more you do it the better you'll get, but I don't think I'll see much of an improvement in my 'Bu.

 

The problems experianced with the Jeep may be due to it being automatic (assuming, since most are anymore), and the pump not being driven while the Jeep is coasting. Think about it the same as towing it, any automatic car needs to have the drive wheels off the ground when being towed, to avoid transmission damage, when the engine is not running.

A manual tranny would be the way to go to use this engine off coasting technique, though I don't know how comfortable I feel with people around me doing this, lack of power steering, lack of power assist for the brakes, etc.

 

On a similar note, I final set a record in my Girlfriends Prius the other day, I made all the way to 40 Kph before I had to stop, with out the gas engine kicking in, I bet I could have made it to at least 45, had there been more distance to do so.

 

As far as the original topic goes, something small, light, and tunable, well anything can be tuned, and with your experiance tuning the OBD1 GM ecm you can either retro fit a GM ECM to what ever engine you choose, or apply what you know to a new ECM. Using something with SFI would be a good idea as well, though there are debates on just how effective SFI really is to economy.

 

I'm thinking a Geo Metro 3 cyl, with a light 5-speed tranny behind it from somthing like a Miata, or even a Z car (no, I don't believe they will bolt up).

 

Why not go for the gusto and convert to electric? I'm doing this with my Jimmy, yeah I know, wrong vehicle to start with to do this, but it's what I have and I need something that will haul and tow, which with the way I will be designing the electric drive shouldn't be much of a stretch.

[seanof30306]

You wouldn't tune it to be lean under all conditions, just cruise. No different than tunning an engine to be stoich at cruise. Under load you add fuel.

 

I understand that. There's a huge difference between 15.7:1 and 19-20:1, though, especially in cars with older, slower pcms.

 

I'm getting over 400 RWHP out of a 383 GM TBI on 87 octane gas. it's taken years of tuning to get there, and I never could have done it without the embedded lockers emulator. I've created literally dozens of fuel tables, but the slow OBD1 processor is not agile, and, after watching people kill their engines from catastrophic detonation, I don't ever go past 17:1 in my lean cruise tables. I still get better highway MPG now than I did with the stock 305.

 

When you're cruising down the highway at 1700 rpm with your fuel tables leaned out to 20:1, something as simple as a severe wind gust or a slight hill can immediately put you into catastrophic detonation. Even LS1 guys, with much faster PCMs, run into this problem. The further you lean it out, the more vulnerable you are. That's why OEMs tend to tune fat. They're building in a cushion to avoid all the warranty claims.

 

Then there's the gas. Stoich for gasoline is 15.7:1. Start adding in ethanol, though, and Stoich gets progressively fatter. In my state, they can add up to 10% ethanol without having to disclose it. A few months ago, I noticed the mpg on my Jeep fell off about 2 mpg. Drove myself crazy looking for the problem till I found out they were selling a 9% ethanol blend.

 

If I had a superlean tune on my car and put that fuel in it, I'd overwhelm the knock sensors and damage the engine withing a hundred miles.

[seanof30306]

Similar result here, I've been trying some techniques with my Malibu to reduce fuel consumption, and although I have not gone through a full tank yet, using these consumption usage techniques, I'm not seeing muchg of an improvment if any, according to the fuel gauge. I have been driving the Z for the last few days anyway.

 

I would think it's one of those learned things, where the more you do it the better you'll get, but I don't think I'll see much of an improvement in my 'Bu.

 

I think it is a learned thing, and you should see results in any car. I've had my Jeep for 12 years, and never got better than 16-17 mpg. Just changing my driving techniques puts me consistently in the low 20s.

 

It is really hard to do at first. Especially slowing down on the highway. After you get used to it, though, it's no problem. To me, it's actually kinda fun. I'm way more engaged in the process of driving than I used to be. I'm paying more attention to the road ahead of me and the traffic around me.

 

 

As far as the original topic goes, something small, light, and tunable, well anything can be tuned, and with your experiance tuning the OBD1 GM ecm you can either retro fit a GM ECM to what ever engine you choose, or apply what you know to a new ECM. Using something with SFI would be a good idea as well, though there are debates on just how effective SFI really is to economy.

 

I'm thinking a Geo Metro 3 cyl, with a light 5-speed tranny behind it from somthing like a Miata, or even a Z car (no, I don't believe they will bolt up).

 

Why not go for the gusto and convert to electric? I'm doing this with my Jimmy, yeah I know, wrong vehicle to start with to do this, but it's what I have and I need something that will haul and tow, which with the way I will be designing the electric drive shouldn't be much of a stretch.

 

The batteries just aren't there for electric conversions yet. What we need is Doc's Mr. Fusion.

 

I'm thinking a z-car might make a good candidate for this because it's light, roomy, and most importantly, cool. I'm a car guy. Just because I'm rechannelling my interests towards economy doesn't change the fact that I want my baby to look good and excite me.

 

I managed to establish the fact that I have a large penis a long time ago, and no longer need to run sub 12 second quarter miles or do burnouts at the Sonic to impress the laaaadies. Bringing a S30 hypermiler in at 2400 lbs, or less, with 150 rwhp and 30+ mpg while still being able to bend a few corners at the autocross would be pretty cool.

[kiwi303]

Butting in on the engine choice, why not look at a SR20DE. Theres plenty of SR20DET stuff and help available for the conversion, they're fairly useful engines and being aluminium they're lighter than the stock L28 and many iron block I4's.

I have a SR20DE engined Serena van that does better MPG than most 2L sedans with better aerodynamics, most of those sedans are cruising at 2900 to 3100 revs at 100Km/H while my van does 2400rpm at 100Km/H. Just fit a tall diff ratio and they'll cruise at low revs quite happily.

[cygnusx1]

Whatever you decide to build, make sure you share it here. I am definitely interested in cool cars that use less gas. I would love to have a Z as a daily driver that got me back and forth to work at 40mpg! When I wanted a scare, I could jump back into the gas guzzler version.

[olie05]

I guess there is one thing that everyone is sort of forgetting about. If you really want to save fuel, and put out insane numbers, its going to happen at interstate speeds. This is where the Z fails, because of its poor aerodynamics.

 

Take a look at any high mileage production car out there, and there have been sacrifices made for aerodynamics. The CRX hf had no hatch wiper and no passengers side mirror.

 

The insight has EXTENSIVE aero consideration.

 

Personally, if I was hunting for a car to "hypermile" in I would go for a Geo metro.

 

as a side note, I was totally anal about logging all my fuel mileage numbers (i'm talking excel spreadsheet with correction factors here), until I realized that I wasn't having fun driving my car anymore and all I could think about was how poor the mileage was. The next thing to do, for me at least, was to stop logging the mileage, and not think about the mileage.

 

Now I just enjoy the ride.

[Nick56289]

 

More importantly, the technique is called "auto stop" for a reason. Here's a typical auto stop situation: I'm driving down a surface street at 35 mph. 200 yards ahead of me, a light goes red, so I pull in the clutch and shut off the engine, coasting up to the light. Absolutely, positively nothing unsafe about it.

 

Heres a situation. Im sitting at a stopsign on a road that enters another road where the speed limit is 55 mph waiting for a car that is approaching quickly. Suddenly a minivan plows into the back of my bike and pushes me into the middle of the intersection directly in the path of the oncoming car. Because I left my bike running I was able to accelerate off the road and out of the way of the oncoming car. I was hurt (broken wrist) but I would have been dead. Also if I could have seen the minivan coming (it came out from behind a corner) then I could have simply moved out of the way. In fact I always leave my bike in first gear with the clutch in at stop. Sitting at a stoplight with the engine turned off is not safe. Especially not on a bike. That form of hypermiling is not worth the extra gas.

 

I could give you dozens more examples where the throttle has saved me from a crash. I agree that it is much more fun to modify you vehicle for better gas mileage than to sacrifice safety.

[seanof30306]

Heres a situation. Im sitting at a stopsign on a road that enters another road where the speed limit is 55 mph waiting for a car that is approaching quickly. Suddenly a minivan plows into the back of my bike and pushes me into the middle of the intersection directly in the path of the oncoming car. Because I left my bike running I was able to accelerate off the road and out of the way of the oncoming car. I was hurt (broken wrist) but I would have been dead. Also if I could have seen the minivan coming (it came out from behind a corner) then I could have simply moved out of the way. In fact I always leave my bike in first gear with the clutch in at stop. Sitting at a stoplight with the engine turned off is not safe. Especially not on a bike. That form of hypermiling is not worth the extra gas.

 

I could give you dozens more examples where the throttle has saved me from a crash. I agree that it is much more fun to modify you vehicle for better gas mileage than to sacrifice safety.

 

I'm sorry that happened to you, but that is an extremely unlikely scenario.

 

I used to have a girlfriend who had been struck by lightning out on a golf course on a clear day. She lived, but her parents didn't. Does that mean I should never go on a golf course again?

 

When warm, my bike starts in less than a single revolution of the engine. Sitting at a traffic light with my thumb over the start button, I'm confident I can start the engine in time to react to virtually any situation that comes up.

 

Regardless, this thread was created to discuss possible engine choices for a hypermiler Z, not to debate the safety of various hypermiling driving techniques. Please don't hijack the thread.

[seanof30306]

I guess there is one thing that everyone is sort of forgetting about. If you really want to save fuel, and put out insane numbers, its going to happen at interstate speeds. This is where the Z fails, because of its poor aerodynamics.

 

Take a look at any high mileage production car out there, and there have been sacrifices made for aerodynamics. The CRX hf had no hatch wiper and no passengers side mirror.

 

The insight has EXTENSIVE aero consideration.

 

Personally, if I was hunting for a car to "hypermile" in I would go for a Geo metro.

 

as a side note, I was totally anal about logging all my fuel mileage numbers (i'm talking excel spreadsheet with correction factors here), until I realized that I wasn't having fun driving my car anymore and all I could think about was how poor the mileage was. The next thing to do, for me at least, was to stop logging the mileage, and not think about the mileage.

 

Now I just enjoy the ride.

 

I don't think it's a question of "fail", or "pass". People on this site, for the most part, own their Z-cars as a hobby. No matter what they're doing with them (top end, 1/4 mile, road race, autocross, etc., there are generally better choices. people modify Z-cars for those purposes because they like Z-cars.

 

This is no different. Sure, I could buy a CRX HF, or Yaris ..... but, I'd have a CRX or a Yaris, not a Z-car.

 

Modifying an S30 for hypermiling is just another direction for these awesome cars to go in. It doesn't mean the Z-car will be the best hypermiling car there is, it means you can hypermile, and still drive a Z-car!

[naviathan]

I guess there is one thing that everyone is sort of forgetting about. If you really want to save fuel, and put out insane numbers, its going to happen at interstate speeds. This is where the Z fails, because of its poor aerodynamics.

 

Take a look at any high mileage production car out there, and there have been sacrifices made for aerodynamics. The CRX hf had no hatch wiper and no passengers side mirror.

 

The insight has EXTENSIVE aero consideration.

 

Personally, if I was hunting for a car to "hypermile" in I would go for a Geo metro.

 

as a side note, I was totally anal about logging all my fuel mileage numbers (i'm talking excel spreadsheet with correction factors here), until I realized that I wasn't having fun driving my car anymore and all I could think about was how poor the mileage was. The next thing to do, for me at least, was to stop logging the mileage, and not think about the mileage.

 

Now I just enjoy the ride.

The Z might not be the best car for "hypermiling", but I don't think it has anything to do with the aerodynamics. Sure the aerodynamics aren't the best, but they're adequate enough for 65mph. The problem I see is the gear ratios. Especially with the automatics. My Fairlady automatic runs over 3k RPMs at 60mph. I couldn't see trying to stretch it out on the highway to 80mph. I wish I could find a higher gear rear end or another transmission (automatic, the wife drives it too) to lower RPMs. I'd prefer something like the diff that was on the forums recently. I just can't see spending the money and I don't need LSD. I'm not concerned with performance in that car, just looks.

[cygnusx1]

This thread has been a bumpy road let's get it back on topic. What engine would be a good choice to make a Z get outstanding mileage without being too slow to drive safely.

 

I am going out on a limb to say an early 1990's 1.5 Honda motor with a TON of mods to be able to mount it longitudinally in the Z.

 

It worked in my Civic so it should work in a Z.

[seanof30306]

This thread has been a bumpy road let's get it back on topic. What engine would be a good choice to make a Z get outstanding mileage without being too slow to drive safely.

 

I am going out on a limb to say an early 1990's 1.5 Honda motor with a TON of mods to be able to mount it longitudinally in the Z.

 

It worked in my Civic so it should work in a Z.

 

Kiwi's SR20DE suggestion is interesting, especially if you could mount it using the cradles for the SR20DETs.