Modding for Fuel Economy?

johnnyi · Post by **johnnyi** » Mon Sep 03, 2007 7:02 am

I purchased my Vibe two weeks ago and found these forums. I have been lurking, reading, searching....great forum by the way.First mod is going to be cruise control.Thus far happy with this car being a slow sipper...avergaging 32MPG CITY/HWY with a 07 base model 5 Speed Stick and the AC Blaring. Are there any mods that would boost/yield better fuel economy? I was looking at aftermarket air intake/filters, upgrading spark plugs and possibly changing the muffler but not sure if it will help or degrade fuel economy.I really wanted to get the GM SuperCharger, as i wanted a little umph, but noticed there is no support for the 07 Vibe.Gotta say, this car has surprised me...Thanks again,John

KNINE · Post by **KNINE** » Mon Sep 03, 2007 7:14 am

The cruise control mod is actually very easy. Why it's so easy, even a K-NINE can do it. You will need to remove the green wire from the original connector behind the air bag (this is your horn ground) and install it in your cruise control connector. I don't know why the cc connector doesn't include the horn ground. I used a one inch wood bore bit to cut the plastic on the steering wheel to push the cc lever through. It made a very clean cut and (if I do say so myself) looks factory. I have to go now, my arm is cramping from patting myself on my back.

prathman · Post by **prathman** » Mon Sep 03, 2007 8:26 am

Yes, the cruise control addition is highly recommended. The green wire swap mentioned by K-Nine was the only tricky part - apparently I accidentally broke the wire inside the insulation so the horn didn't work at first. Once I fixed the wire and reinserted it into the connector it's been working great - and the cruise button was very welcome on our last CA to WI trip. RockAuto and AutoPartsGiant are two sources for the control stalk for under $40.Good luck on your quest for better mileage. My impression is that the car is pretty well tuned for that already and any modification that gives you an improvement will also have some significant drawbacks. For example, a less restrictive air filter may give a bit better mileage but might also let in more fine particulates that won't be good for the engine in the long run.

kostby · Post by **kostby** » Mon Sep 03, 2007 9:35 am

Here are a few ideas, off the top of my head:Lower the rolling resistance.Keep tires fully inflated (35psi or more) The narrower and higher aspect ratio of stock Toyota Corolla 15" wheels & tires would probably increase mileage slightly over the stock 16" and slightly wider Vibe wheels and tires.Lower wind resistance.Keep the windows up. It's more efficient to use the A/C than roll the windows down which increases drag.Remove the roof rack crossbars (if applicable).Keep it waxed & washed.Keep your foot out of the throttle.Keep RPM below 3000 whenever possible, because these 16-valve engines get relatively thirsty above 3000 RPM.Remove unneeded weightRemove all unnecessary items from storage compartments and the 'trunk'. This might include removing the jack and the spare if you belong to a good auto club and drive mostly near home.Avoid quick starts and sudden stops. Pretend there's a raw egg between your foot and the gas pedal. Observe posted speed limits. 'Draft' behind high-profile vehicles at a safe distance. I got 41.3 mpg on a 300 mile road trip through Tennessee and Kentucky doing this once.Disconnect the battery for a couple of hours, so the ECU will re-learn your new grandma-like conservative driving habits.Lowering springs MIGHT increase gas mileage because they would slightly lower the vehicle profile, but this is only speculation on my part.

goodvibe · Post by **goodvibe** » Mon Sep 03, 2007 10:17 am

I read that BMW did some studies on fuel efficiency and driving style with a manual. Their recommendation was to get up to speed briskly as in use the pedal more than you'd expect in the highest appropriate gear. Shift into the top appropriate gear asap. I think they found that getting to high gear faster was more efficient than spending more time in the lower gears and accelerating at a slower pace. The egg under foot is correct for all other driving. Somebody should look at the fuel curve and see at what throttle position and RPM things start to get rich, adapt it to this scenario and give it a try. Sure would make saving gas a lot more fun if it worked.

silver_vibe · Post by **silver_vibe** » Mon Sep 03, 2007 12:14 pm

Quote, originally posted by kostby Â»Lower wind resistance.Keep the windows up. It's more efficient to use the A/C than roll the windows down which increases drag.There have been a couple MythBusters tests on this with different results. I think the conclusion was going less than 50mph it is more efficient to leave your windows down, but going greater than 50mph it is more efficient to use your A/C. Of course that was for the SUV they used.My personal experience is an overall loss of about 1-2 mpg when I use the a/c. My comfort is worth the 1-2 mpg loss to me.OFF TOPIC: This is my beelzebub post.

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JohnC · Post by **JohnC** » Mon Sep 03, 2007 12:38 pm

I get my best mileage when i have the scan gauge installed. It reminds you what your mileage is as you drive...kinda like a nagging wife.

johnnyi · Post by **johnnyi** » Mon Sep 03, 2007 1:03 pm

I would probably like the scan gage better, cheaper too. Just finishing up a divorce here.

johnnyi · Post by **johnnyi** » Mon Sep 03, 2007 1:19 pm

Quote, originally posted by kostby Â»Keep your foot out of the throttle.Keep RPM below 3000 whenever possible, because these 16-valve engines get relatively thirsty above 3000 RPM.Avoid quick starts and sudden stops. Pretend there's a raw egg between your foot and the gas pedal. Observe posted speed limits. 'Draft' behind high-profile vehicles at a safe distance. I got 41.3 mpg on a 300 mile road trip through Tennessee and Kentucky doing this once..Yeah - I've been driving like a granny and keeping the RPMs between 2000 - 2500. Seems to be working but then I am not going anywhere fast.I've tried drafting, definately fun to do on long road trips, but not something I want to do everyday. Being able to read the serial numbers off the back of a truck scares me... On starting, I haven't driven a stick in several years but it feels like the release on the clutch is high/loose. Finally getting the feel of it.- John

ProtonXX · Post by **ProtonXX** » Mon Sep 03, 2007 1:28 pm

I mod all the time for mileage. Heres what I didTires @ 45psi +Light weight Rims +Taller Tires +Fuel Heater +Hydrogen +/-Seafoam ++Octane Booster +Pulleys ++Pulseplugs(still in the air)Bigger Cat Converter (still in the air)Grounding Cables +/-Helix +/-2nd O2 sensor unplug--Fuel Trimmer ++/-Scan gauge ++Bad ModsAir Intake --High octane gas -Low profile tires -end result max 31mpg up form a min of 23 mpg

ragingfish · Post by **ragingfish** » Mon Sep 03, 2007 4:51 pm

Damn you all!My average ratings are 22-24mpg -- and that's 60/40 highway/city driving, and actually being "gentle" on the throttle. Damn 6 cylinder engines!

ProtonXX · Post by **ProtonXX** » Mon Sep 03, 2007 11:00 pm

damn vibe, my 160hp grand am gets 30 mpg too

redlava · Post by **redlava** » Tue Sep 04, 2007 7:05 am

If you are looking for fuel economy above all else then I would NOT put on an intake or muffler. The manufacturer says that it improves the fuel economy, but it usually does not. If anything it will hinder it. I went from 34 mpg to about 29-30 mpg with an Injen intake and Magnaflow exhaust. But I do enjoy the sound of my car and the little added power.

ProtonXX · Post by **ProtonXX** » Fri Sep 07, 2007 2:01 am

Im not actually replacing the muffler. Just the mid pipe with the cat converters. Hopit it doesnt drop mileage

johnnyi · Post by **johnnyi** » Thu Sep 13, 2007 11:29 am

Quote, originally posted by ProtonXX Â»Seafoam ++What did you do with the Seafoam? Sound deadening or flotation safety if you ever get stuck in a flash flood? My assumption is you used seafoam in the door panel for sound deadening...curious let me know.

johnnyi · Post by **johnnyi** » Thu Sep 13, 2007 11:33 am

Is anyone using the K&N Airfilter? Experiences and how did it effect your gas milage?If it improves it, then not a bad deal to have one filter for the life of the vehicle.Also going to move to synthetic oil at my first oil change interval - Mobil 1 seems to the the most popular. I was reading posts on the extended change oils, sounds like snake oil and too good to be true.

silver_vibe · Post by **silver_vibe** » Thu Sep 13, 2007 11:34 pm

Quote, originally posted by johnnyi Â»Is anyone using the K&N Airfilter? Experiences and how did it effect your gas milage?http://forums.genvibe.com/zerothread?id=9361By the way, since I posted those findings in 2004, I've gone back to using stock air filters.

BlueCrush · Post by **BlueCrush** » Thu Sep 13, 2007 11:41 pm

Quote, originally posted by johnnyi Â»What did you do with the Seafoam? Sound deadening or flotation safety if you ever get stuck in a flash flood? My assumption is you used seafoam in the door panel for sound deadening...curious let me know.LOL!http://www.seafoamsales.com/motorTuneUp ... ki/Seafoam

GMJAP · Post by **GMJAP** » Thu Sep 13, 2007 11:53 pm

The mod that's going to improve mileage the most is your driving style! The "accelerate as fast as possible in the highest gear possible" works well. There are a few people here (including myself), who regularly average about 35-36mpg per tank.I have a K&N filter - don't expect dramatic or immediate results. It increased my average mileage a little over 1mpg.Finally, stock tires are low rolling resistance. If you get new tires that aren't, expect your mileage to drop 2-3mpg.

Daox · Post by **Daox** » Fri Sep 14, 2007 12:11 am

I've been hypermiling to work and back (35 miles to work 90% highway) for the past couple weeks on and off. I've been averaging roughly 45 mpg (according to my scangauge) when doing this. Unfortunately, I carpool with my wife who then procedes to drive the car normally through the city for the remainder of the day. I usually end up averaging high 30s per tank. Modifications to the car are nothing special with regards to mileage and actually the high performance tires probably increase rolling resistance. If I were the only one driving the car this puts me fairly close to the 50 mpg goal I am aiming for... and I haven't even done anything with the car yet. Unfortunately, I haven't had any time to work on the car as I'm whole heartedly working on another to get it up and running before winter rolls around.

prathman · Post by **prathman** » Fri Sep 14, 2007 12:20 am

Quote, originally posted by johnnyi Â»Is anyone using the K&N Airfilter? Experiences and how did it effect your gas milage?If it improves it, then not a bad deal to have one filter for the life of the vehicle.Keep in mind that the primary function of the air filter is to protect your engine from particulates in the air. I've seen a number of tests that show less effective filtering by the K&N and similar oiled filters when compared to OEM paper style. Here's one:http://www.bobistheoilguy.com/...3.htmSo while they may give some marginal improvement in gas mileage, it's likely to be at the expense of some increased engine wear in the long run.

ragingfish · Post by **ragingfish** » Fri Sep 14, 2007 12:49 am

Quote, originally posted by prathman Â»Keep in mind that the primary function of the air filter is to protect your engine from particulates in the air. I've seen a number of tests that show less effective filtering by the K&N and similar oiled filters when compared to OEM paper style. Here's one:http://www.bobistheoilguy.com/...3.htmSo while they may give some marginal improvement in gas mileage, it's likely to be at the expense of some increased engine wear in the long run.I happened to see that same report, which is the main reason when it was time to recharge my K&N drop in on the G6, I "dropped" the filter "in" the trash. I have now reverted to traditional disposable ACDelco filters. Not to mention since reverting to paper (or gauze, whatever the ACD filters are made of), I actually gained a 1-2mpg boost in fuel economy.

Petrucci914 · Post by **Petrucci914** » Fri Sep 14, 2007 2:28 am

45 PSI!? Looking to pop your tires or ride on 2 inches of tread? Not good for the longevity of your tires.

Kamikaze · Post by **Kamikaze** » Fri Sep 14, 2007 2:45 am

BOOM!!!Quote, originally posted by Petrucci914 Â»45 PSI!? Looking to pop your tires or ride on 2 inches of tread? Not good for the longevity of your tires.The amount of MPG gained won't equal the amount of $ spent to replace the tires when they are prematurely worn out.

johnnyi · Post by **johnnyi** » Fri Sep 14, 2007 4:32 am

Quote, originally posted by BlueCrush Â»LOL!http://www.seafoamsales.com/motorTuneUp ... /SeafoamOk, now I feel like an a__. I've been also reading boat making forums and was thinking of sea foam as used in boating...Just clicked on your link bluecrush and saw the product..

johnnyi · Post by **johnnyi** » Fri Sep 14, 2007 4:39 am

Quote, originally posted by GMJAP Â»The mod that's going to improve mileage the most is your driving style! The "accelerate as fast as possible in the highest gear possible" works well. There are a few people here (including myself), who regularly average about 35-36mpg per tank.I have a K&N filter - don't expect dramatic or immediate results. It increased my average mileage a little over 1mpg.Finally, stock tires are low rolling resistance. If you get new tires that aren't, expect your mileage to drop 2-3mpg.I've been real happy with the mileage, guess I need to get my shifting down and I can get the extra 2-3MPG. but roughly getting 31 - 33MPG per tank. I don't have a scan gage but just looking at the amount of gas going in the tank and dividing that into the trip meter. I really do love this car...

Kamikaze · Post by **Kamikaze** » Fri Sep 14, 2007 4:40 am

Quote, originally posted by johnnyi Â»Ok, now I feel like an a__. I've been also reading boat making forums and was thinking of sea foam as used in boating...Just clicked on your link bluecrush and saw the product..Thanks for the Laugh!

johnnyi · Post by **johnnyi** » Fri Sep 14, 2007 4:46 am

Quote, originally posted by Daox Â»I've been hypermiling to work and back (35 miles to work 90% highway) for the past couple weeks on and off. I've been averaging roughly 45 mpg (according to my scangauge) when doing this.Wish I could get to that range but my driving is mixed (City/Hwy) so realistically, if I get to the 35MPG, I will be estatic. I used to have a 2000 Altima and it was starting to suck up gas...15 Gallon Tank and avg just about 20MPG. So the Vibe is a huge money saver with a 12G Tank and 30+MPG.

johnnyi · Post by **johnnyi** » Fri Sep 14, 2007 4:59 am

Quote, originally posted by prathman Â»Here's one:http://www.bobistheoilguy.com/...3.htmSo while they may give some marginal improvement in gas mileage, it's likely to be at the expense of some increased engine wear in the long run.Interesting read...So, I guess this puts and end to the subject of improving mileage..Stick with Stock ComponentsGet upto speed quicklyShift accuratelyKeep tires inflated properlyEnsure you always have a clean air filterStick with OEM Airfiler as it allows less partacles throughMaintain regular maintenance..

Daox · Post by **Daox** » Fri Sep 14, 2007 5:20 am

There are many additional modifications you can do for fuel economy... however, the pool grows murky as you start to look at a lot of them as different cars/engines react differently to different modifications. Aero mods are a plus, but work much more effeciently as you increase speed. Tuning exhaust and intake pipe diameter as well as a properly designed header will alter when maximum torque is produced and this effects mileage. Cam timing is also something that could be tweaked for mileage and hopefully is on our cars. I have yet to see any testing to this effect. Changing a lot of these things isn't very easy and usually costs more than the savings in gas. However, it can be done.

kevera · Post by **kevera** » Fri Sep 14, 2007 5:25 am

Did you ever get around to doing this Daox.http://forums.genvibe.com/zerothread?id=28737

Daox · Post by **Daox** » Fri Sep 14, 2007 5:32 am

Unfortunately no. At least not yet. It hasn't been forgotten. I've just been too busy working on my other car. Installing a custom supercharger setup takes some time. The only thing I have done thus far is change my driving style.

GMJAP · Post by **GMJAP** » Fri Sep 14, 2007 7:09 am

Quote, originally posted by Daox Â»I've been hypermiling to work and back (35 miles to work 90% highway) for the past couple weeks on and off. I've been averaging roughly 45 mpg (according to my scangauge) when doing this. What kinds of hypermiling are you using?

VivaVibe · Post by **VivaVibe** » Sat Sep 15, 2007 3:37 am

Quote, originally posted by GMJAP Â»What kinds of hypermiling are you using?Huh?! They have a special name now for driving sensibly? I didn't see anything in that article which isn't common sense for someone trying to maximize MPGs. I was hoping it would reveal some little known hints.

Daox · Post by **Daox** » Mon Sep 17, 2007 12:25 am

Quote, originally posted by VivaVibe Â»Huh?! They have a special name now for driving sensibly? I didn't see anything in that article which isn't common sense for someone trying to maximize MPGs. I was hoping it would reveal some little known hints. Actually, there are special driving techniques that can be used to greatly increase fuel economy. Some people go to extremes and sometimes dangerous lengths to do this. Take everything you read with a grain of salt.As far as hypermiling goes I've been using mainly the pulse and glide technique (engine on). This is a technique based on the fact that air throttled gasoline engines run most effeciently at wide open throttle (no restriction for the engine to overcome). What you do is speed up to a max speed of your choice (for example you speed up to 60 mph on a 55 mph road). Once you hit 60 mph you push in the clutch and coast down to your minimum speed of your choice (say 55 mph). This is your glide. Once at 55 mph you rev match and re-engage the clutch and speed back up to 60 mph at near wide open throttle (this is the pulse). Some of the more extreme drivers actually turn their engines off while gliding. This is quite dangerous IMO as you have no engine power if you need it. However, it greatly increases fuel economy and some hybrid vehicles actually do this on their own. Just so you have an idea why this works. Those of you with a scangauge have probably noticed this already, but when you are coasting at around 60 mph with the clutch in you are getting roughly 250ish mpg. When you are accelerating you are getting around 20ish mpg. As you can see, it doesn't take long while coasting at 250 mpg to bump up your average mileage over a trip.I have found that the 1ZZ doesn't like to P&G at over about 65 mph. When I push in the clutch to glide, the engine does not idle down right away and it greatly kills the effectiveness of the technique. I'm guessing this is the way Toyota programmed their engine, but I also have an e-manage blue installed and don't know if that effects it somehow. I have by far not perfected this technique either as I've only been doing it a short while. There is definilty a time for it, and a time to drive normally though. However, the more I do it, the easier I find it is to fit it into my normal driving routine. I won't lie though, it is kind of a pita to do and does require a fair amount of concentration, especially during city driving and more congested highway driving.Here is a link to a site that lists off quite a few different techniques. While it is aimed more for hybrid vehicles it is still applicable to normal vehicles.http://www.cleanmpg.com/forums....html

NibCrom · Post by **NibCrom** » Mon Sep 17, 2007 3:57 am

Does anyone know how much weight you would have to remove from the car to notice improved fuel economy? Just curious/speculating...

GMJAP · Post by **GMJAP** » Mon Sep 17, 2007 4:28 am

Quote, originally posted by Daox Â»As far as hypermiling goes I've been using mainly the pulse and glide technique (engine on). This is a technique based on the fact that air throttled gasoline engines run most effeciently at wide open throttle (no restriction for the engine to overcome). What you do is speed up to a max speed of your choice (for example you speed up to 60 mph on a 55 mph road). Once you hit 60 mph you push in the clutch and coast down to your minimum speed of your choice (say 55 mph). This is your glide. Once at 55 mph you rev match and re-engage the clutch and speed back up to 60 mph at near wide open throttle (this is the pulse). Some of the more extreme drivers actually turn their engines off while gliding. This is quite dangerous IMO as you have no engine power if you need it.How much doese this increase clutch wear? Seems like you might wind up spending the gas money saved on new clutches.Also, turning the engine off is extremely dangerous as you also lose power steering (and ABS).

Kamikaze · Post by **Kamikaze** » Mon Sep 17, 2007 4:33 am

not to mention the amount of wear for starting the engine after every time of shutting it down. My parents have 2 prius's (dad liked mom's so much bought one for himself) I've gotten to drive them and the way it starts and stops the gasoline engine feels and sounds WAY different than shutting off or starting our vibe's. I think, not positive, but when the electric motor is running and you get on the gas, enough to make the gas engine kick in, it's kind of like popping the clutch to start the gas motor, only it achieves this way smoother than we can do with manual trans. just my 2 cents

Daox · Post by **Daox** » Mon Sep 17, 2007 5:09 am

Yes, clutch wear is increased depending on how good you are at rev matching when you go to accelerate again. You get used to it pretty quick though. My passengers normally can't even tell I'm doing it.The hypermilers using engine off coasting do pop the clutch to restart the engine versus using the starter. When using the starter, the engine injects additional fuel for easy starting and negates a lot of the benefit. As I originally posted, I agree this is dangerous and wouldn't recommend it.

VivaVibe · Post by **VivaVibe** » Mon Sep 17, 2007 6:47 am

Quote, originally posted by Daox Â»Here is a link to a site that lists off quite a few different techniques.Still didn't see anything special there which is not specific to hybrids. I doubt the P&G would be very effective with an auto-tranny. Last fill-up was 34 MPG with mostly city driving, so I'm probably getting close to max anyway.

Daox · Post by **Daox** » Mon Sep 17, 2007 7:19 am

There are people who P&G with automatic trannys believe it or not... IMO its definitly not worth it. The slushbox has always been the bane of mileage on smaller engines, nothing new there unfortunately.I don't see how you missed a bunch of other techniques though. Here are a few:Slow down. More speed means more air friction to overcome.Drafting. This one can help quite a bit at highway speeds, again with the air friction.Driving without brakes (must read the technique, you don't actually drive without brakes)

VivaVibe · Post by **VivaVibe** » Tue Sep 18, 2007 6:54 am

Quote, originally posted by Daox Â»I don't see how you missed a bunch of other techniques though. Here are a few:Slow down. More speed means more air friction to overcome.Drafting. This one can help quite a bit at highway speeds, again with the air friction.Driving without brakes (must read the technique, you don't actually drive without brakes)I didn't miss them. Not meaning to be difficult, nor discount the benefit of these methods for those unaware of them. I just don't see them as being new or special.Slow down... a no-brainer and pretty well known.Drafting... old techniques that can be dangerous, will make truckers angry, and probably get you a ticket if not an accident. Besides, this method is only of benefit on the open road.DWOB... another rather common method of avoiding the stop-n-go, or speed up-n-slow down tendency of many drivers. Only works in light traffic, with signals that are syncronized for traffic flow, and those without cross traffic triggers. If you are familiar with the route, it can work. This is something I do all the time as just a normal part of driving.Alternate routes is probably one of the best bits of advice given. If you know the area you are driving through, and take some time to find better ways, it can really pay off.For instance, on my commute home from work, the last four miles of the route takes a 4-lane street with speeds of 45-50 MPH, and five traffic lights. With normal commute traffic it is difficult to maintain an even speed, and stops at several of the lights is likely, with one of them requiring 2 or 3 stops to get all the traffic through it.I usually take an alternate way which has about half of it 4-lanes then two lanes, speeds of 30-40 MPH, 2 traffic lights and one stop sign, and much lighter traffic. It takes about the same time to traverse, and I'm pretty sure it is more efficient with better MPGs.Hypermiling techniques are about modifying your driving style and habits which is probably the cheapest and most effective way to improve MPGs. However, I think the intent of this thread was more about modding the physical and performance aspects of your car to get better mileage. Especially the little things you might overlook. In any case, it's all very good info.I think the Vibe is already engineered to be pretty efficient, and squeezing out a little more is a challenge. With today's fuel prices any gain would be a benefit.

Daox · Post by **Daox** » Tue Sep 18, 2007 7:42 am

Sorry, thats about all I have up my sleeve of tricks. Stick around that site and I'm sure you'll figure out some more. You can also check out http://www.gassavers.org/ (they don't focus on hybrids there). They have a bunch of guys there getting crazy mileage... One of the top guys is running a Ford ZX2 at just over 100 mpg. Of course he has taken things to the extreme.I agree with you on nearly every point you made. However, I do think drafting can be done at a safe distance. As shown in the picture below this leaves adequate distance to stop. I also do practice DWOB in rush hour traffic as much as possible. You have to scale the technique with the flow of traffic. Stop and go is hard to do, but if traffic is just creeping along a spurt of gas here and coast for a while results in fairly descent mileage.I would definitly agree the 1ZZ is a very highly developed and effecient engine. The little sucker stays in closed loop nearly ALL the time. This means greater fuel effeciency at higher engine loads as well as cruise. It also has individual coil packs which provide optimum spark energy when compared to older single coil pack designs. I could go on about the additional features, but won't. It is a good engine and it isn't easy to improve upon that. However, I will try.

Daox · Post by **Daox** » Tue Sep 18, 2007 10:14 pm

Those are great points and you are mostly correct. Gliding in gear will shut off the injectors (I'll have to double check my zeitroix datalogs, but I'm pretty sure it does). However, your still spinning the engine and compressing air in the cylinders. This ends up shortening your glide quite a bit. In the end, an idling glide is more effecient than a glide in gear using nearly no fuel. I have seen testing done to verify this.

GMJAP · Post by **GMJAP** » Sun Sep 30, 2007 12:36 pm

So I tried P&G for a tank. It increased my mileage about 2 MPG. (I do ~ 70%Hwy/30%City)Can't say I feel it's worth it considering1) As Doax noted, it's a major pita2) It's a great way to (removed) off other drivers (as you accel, slow, accel, slow etc.)3) clutch wear.Of course, as a side effect, it reduce my average speed (P&G from 60-65, whereas I normally set cruise on 65) so that may account for some of the 2 MPG too.It was quite a feeling of relief to finish that "test tank" and start driving normally again!

Daox · Post by **Daox** » Tue Oct 02, 2007 12:45 am

Thats cool. I'm glad someone took the time to at least try it out.There are definite downsides to it. I don't do it constantly when I drive. Sometimes I just don't feel like it. However, once you do it longer you do get better and it becomes more natural. To each their own though. As you can tell from my new signature, its does have its benefits, and I'm not even the one who drives the car most of the time.

zionzr2 · Post by **zionzr2** » Thu Oct 04, 2007 3:14 am

one thing a lot of the hypermilers are doing (NOTE, THAT I AM NOT ENDORSING THIS METHOD) is to over-inflate their tires to near treadwall max pressure.

jamesmetairie · Post by **jamesmetairie** » Sun Oct 07, 2007 1:29 am

safe drafting distance=? i,ve seen a few truck tires blow . i think i,d rather just pay for the extra gas (lower mpg,s).

joatmon · Post by **joatmon** » Fri Oct 12, 2007 10:27 am

Today I did some experimenting, and I can not figure out a way to coast or engine brake in gear that turns the injectors off. Coasting in idle (was at night, headlights on) scangauge was reading 0.2 gallons per hour, put it in gear to slow down, fuel rate went up to 0.4 gph, not down to zero. If someone else with a scan gauge can come up with a repeatable way to have the engine "running" but have fuel rate drop to zero, let me know.

prathman · Post by **prathman** » Fri Oct 12, 2007 11:18 am

Quote, originally posted by joatmon Â»Coasting in idle (was at night, headlights on) scangauge was reading 0.2 gallons per hour, put it in gear to slow down, fuel rate went up to 0.4 gph, not down to zero. If someone else with a scan gauge can come up with a repeatable way to have the engine "running" but have fuel rate drop to zero, let me know.I remember seeing a discussion where it was claimed that the ScanGuage doesn't give correct readings during engine braking when the injectors are shut down. I'm not familiar enough with the details of what data the SG gets from the diagnostic port to know if this is true, but it might account for your results.