Nycgs300

Thanks alot for this info,it's greatly appreciated and will be used on the road.

Sampak

You're welcome, however I visited that link someone posted earlier and WOW there is a lot of good common sense and some not so common sense info in there. A LOT of it is habit and driving conscientiously but it can and will make a difference.

Here's an example I literally tried after reading the whole article. Last 2 days my GS400 has been getting about 21 MPG after my 37 mile trip to and from work. This morning on my way to work, I made a conscious effort to see if I could control my habits and temptations to accelerate the car hard every now and then and speed with the speedy cars.

Bottom line is, even after driving and idling in a school zone to drop my daughter off early in the trip, I averaged up to 25 MPG then down to 24.xx MPG when I parked my car finally at work. I had been averaging 21-22 MPG. It might not seem like much, but that's a 9% increase from a V8. Keep in mind most of my driving is highway and 40 mph main roads, with the start and 1/3rd of the last part in city traffic. Your results on the i6 3.0 may vary (should be 1-2 MPG better really).

BTW I use Scan Gauge II display, best ~$150 I spent on car stuff as of late (Autozone). Gives you a multitude of sensor and OBD2 read outs in real time, yes including MPG live and average, and loads of other info.

Now for the bad news -- it took EFFORT on my part to even drive this way and not fall into bad habits (not coasting before red light, not gassing it on to the next red light, not paying attention to the jam up ahead and coasting, accelerating steadily, and HOLDING the gas pedal steady and not up and down, even on grades and hills). I didn't use Cruise Control whatsoever, as I read and agree with the idea that it wastes some gas trying to maintain a steady speed on uneven roads (hills), when the goal is to keep the gas pedal steady whenever you can or coast over the top of the hill then pick up speed downhill. By EFFORT I mean it was almost hard work LOL. But practice makes perfect.

BTW when I coasted or thought I could coast for a while with no traffic backed up behind me or in front, I popped it into Neutral since that way the engine is not slowing the car down or guzzling some gas as it's revving up/down with the vehicle speed in gear.

Nycgs300

I'll look into getting a scan guage...

NoUltimatu

Do it. I have mine set for water temp, instant gallons per hour (most important imo) and average instant and average trip. Make sure to hit like 45 on a clear road and correct the scanguage to a gps unit like a phone app. You'll get slightly lower MPG ratings but more realistic. Also get GasBuddy or some comparable app and start tracking your mileage. It'll help you a lot. But scanguage helped me get about 1-2 mpg extra. But that was after I already knew how to hypermill pretty well. Last but not least, try to travel after sun set and crack some windows instead of AC. That is about 5 mpg difference in my car (Not Lexus, but tiny Japanese engine).

Nycgs300

Thanks for the advice

Sampak

Nice. I have mine setup for:

Water Temp ----- TPS (throttle sensor)
MPG(instant) ----- MPG AVG

I find that as long as I can keep my foot on the pedal rock steady at exactly 19, 20 or 21% (your readings may vary) depending on my speed at the highway (60-70 MPH), I can maintain an instant MPG reading of about 26-29 MPG. However, when climbing up a gradual slope I have to remember to NOT press down harder and just let the car's momentum fight gravity and usually I barely lose 5 MPH speed, while maintain 25+ MPG, until the incline is cleared.

I found the instant Gallons Per Hour (GPH) display to be too chaotic and meaningless for me (might try again) especially since it has no correlation with my speed which would then indicate just how fuel efficient I am at a given speed (hence, MPG works better for me). The throttle position sensor (TPS) let's me see exactly how heavy I'm going on the gas pedal and therefore control my foot precisely to within 1% (however accurate that itself is I can't say, but I can tell from the engine exhaust tone that it's pretty noticeable to me).

This morning I managed to peak out at around 26.x MPG average over the course of 20-23 miles of mostly 60-70MPH highway driving. Of course it dipped into 21-22 range in town.

The downside to trying to 'hyper-mile' my V8 GS is that I feel so very frustrated having to constantly fight the urge to relieve some boredom or to feel the exhilaration of pressing that pedal down and hearing that exhaust note... I found it almost depressing after 3 days, so this morning on my way to work before the last couple of miles of my 37 mile commute, I just decided to play chase with an unsuspecting S2000 for fun. Ok, so not really, but I stepped a bit harder on the gas off the line to keep up with his heavy foot. Did I feel like a dirty little gas hog? Maybe.

NoUltimatu

Yeah. That's how I drive too. I'll drive really slow everywhere, but if I'm running late I'll be flying through traffic. Or sometimes, I just have that need for speed late at night on the clear highway.

But regardless. I am very in to eco modding and believe that it can definitely run hand in hand with power adders. I mean look at the TDi Audi that wins Le Mans every year. A big part of it is the MPG advantage it has to the other cars.

As soon as I'm able to, I've already set a goal of 35 mpg highway. It's gonna include a full metal underbody a taller last gear (on the Getrag 6spd trans) and going to focus on lightweight rotational mass. Also a bit of carbon (hood/trunk). We'll see if it's possible

gs-ireland

I had the same problem, my solution was to run my GS3 on Propane!!

It went from 24mpg(euro) to the financial equivalent of 42mpg(euro)

Pictures taken during installation :

Sampak

Wow! Well I agree about the taller gearing -- I feel as if my car's missing that 1 last gear -- 6th, which would hopefully bring that 2000-2300 RPM on the highway down to a more V8 appropriate 1500-1800 around 60-70 MPH. I'm sure the engine's got the torque. I guess being a 5spd auto was a big deal back in '98, but it's peanuts compared to the ridiculous 8 speed Lexus models I see advertised on TV now haha. I know I'm only dreaming but it would be just awesome to couple the 1uz to a 6 spd manual or even a modern auto. Would get great MPG and still retain the umph at the bottom end.

As far as modding the car for MPG -- I always wonder where the 3700+ lbs are hiding. The car itself is only just a mid-size, and even accounting for the RWD setup that's almost 200 lbs I can't justify. I'm sure it's all in the reinforcement, carpeting, noise dampening, etc.

NoUltimatu

Without a doubt. It's definitely not an MPG car. I'm saying that under ideal conditions you could have a huge turbo and still have it leaned out in lower RPMs for efficiency. Even 35 is probably a high goal but I would rather aim high and see what I can do with that. Btw it's refreshing to talk to people who actually understand what I'm talking about and not laughing in my face about this topic.

Nycgs300

That's nice,do you still have the same power on propane?

gs-ireland

I can't feel any power difference, but it's on my to-do list to get it dyno'd on both Propane and petrol.

I've done about 6000 miles on propane and the engine oil is still a nice syrup golden colour ! This is the best mod I ever made on the car

Sampak

I have to say, not to bash anyone or Toyota, but the 2JZ is not exactly the most fuel efficient engine in their line up given its displacement and power especially when compared to the 1UZ (both as equipped on the GS, and even on the much lighter IS300), specifically in their '01+ line up when compared to say the VQ35 which debuted in '02 and made more power and still averaged better MPG. But I guess it's obviously just a really dated but reliable engine with VVTI slapped on, meant for all out performance and kind of "wasted" when driven in an N/A application?

With both the factory EPA estimated 2JZ and 1UZ MPG figures in mind on the 2GS, I think if one has to stick to a non-turbo N/A GS, I'd pick the GS400 and just hypermile the F out of it if that was a concern, and enjoy the extra 70% more power for a meager 1-2 MPG loss.

Nycgs300

Did you make the kit or is there a company that make it?

gs-ireland

I picked items from a few different suppliers. All components are certified and designed for propane use in cars