MUCH better gas milage, the old fasion way. Install "taller" fifth gear.

[MPGDOC]

I have developed a new 2 gear set for fifth gear. The original ratio is .725, and these gears change it to .60465. It's a 16.25% larger gear. Three teeth more.The bottom line is now at 60 mph the engine rpm is 2100. The stock gears had the rpm at 2400. At 65 mph, the rpm, with the new gears is only 2200.The factory gears have the rpm at 2550. At 70 mph the rpm is only 2450, compared to 2700 OEM. The transmission DOES NOT have to be removed, just the fifth gear housing. Takes a good Tech about one hour. I am doing more experimentation with a one gallon, hood mounted gas supply to get more exact numbers. I know I am over 40 mpg, highway. I have these gear sets for sale. If you do a lot of highway driving, these could save you some real money. Happy vibe owner. MPGDOC

[northvibe]

holy crap thats cool. Which transmission is this for? auto/manual?

[-fluffy-]

Just to clarify, it's for the 1ZZFE, manual trans. We made 3 sets total, one of them is currently installed in a 2004. I'll have pictures and more info up in a bit.

[Old Tele man]

...remember "back in the day" when people would simply bolt-on a Borg-Warner "Overdrive" unit in place of the original "tailshaft housing" to get better fuel economy at cruising speeds? Some were electric solenoid operated and others were manually engaged.

[-fluffy-]

I'm not old enough to remember that, but my dad does.

[Kincaid]

Cool! Let me know if you make one for the 2009-10 manual.

[djkeev]

Quote, originally posted by Old Tele man »...remember "back in the day" when people would simply bolt-on a Borg-Warner "Overdrive" unit in place of the original "tailshaft housing" to get better fuel economy at cruising speeds? Some were electric solenoid operated and others were manually engaged.Remember back in those days when a VW got 30 + MPG's and Honda could get close to 40 MPG......with a naturally aspirated carburetor fuel system!! Today if a manufacturer gets over 30 MPG they market it like an engineering miracle!Yep, progressDave

[Kincaid]

In a way it is! Nowadays we are lugging around more weight with all the safety equipment, stronger vehicle structure and options.These days the current Honda Civic is as large as the 1st gen Accord and probably weighs 30% more.

[-fluffy-]

We don't have anything for the 08 and up cars, just the 02-07 Matrix/Vibe (does the Corolla or Celica use the same trans?) I've got some pictures to help explain what we're working on here. Currently, we have only built a couple sets of these, and are gauging interest in further production. I can't offer much for pricing information at this time either, as it's something that will depend on interest. We have done instrumented testing on the "Stage 1" set, and the results are excellent thus far. Haven't tested the "Stage 2" set yet. Here's the pictures.

[lovemyraffe]

It is an awesome idea! But is it practical? There are reasons the tranny is geared a certain way. With the taller fifth gear installed, do you have problems with losing speed while going up hills? Do you find yourself shifting gears more often to maintain speed?

[iucu]

I understood what you did ! In fact you can do as many as you want other gears pair to lower the RPM. If this is the scope ! My questions to you are :- did you calculate the shaft who keep the smalest gear because the load in that shaft and bearings are way different now ?- you jumped from speed 4 over to 5 to like speed 6 (consider 6 speed manual transmission) . I do not say no, but you can do that only in special HWY driving conditions... It is like (exemple), not using the 2th anymore, just shift from 1 to 3 to lower the RPM and that is bad and you know very well why !

[-fluffy-]

Umm, what? I have no idea what you're attempting to ask, or implying.

[vibolista]

Very good!! You're making those gear sets? I really like the taller highway gearing idea. Keep us informed how it works out. You are on to something I didn't think could be done.I do something like that with my larger diameter tires, but I only increased my gearing by a measly 4%. Taking it easy on my commutes, I finally hit 40 mpg on my last tank. So, 40 mpg can be reached. Before that, I was getting 37 to 38 mpg. Our weather finally got nice, and that may have had some beneficial influence on MPG.You're going to have to find a sweet spot for engine RPM at cruise and see where that becomes most economical. And yea, you won't have quite as much torque to keep speed on certain hills... but that's what shifting down to 4th is for. In hilly terrain it would take a little more involvement by the driver. Not a bad thing. By the way, the first gen Vibes were all pretty much the same through 08, right? Or is there a tranny difference between 07s and 08s? I didn't think they were different at all.

[Kincaid]

As an aside, I think my 2009 manual cruises at 70 mph at about 2900 rpm. I just drove a friend's old Toyota pick up (automatic) and at 70 mph his rpm's were about 2500.Would be nice to save some gas in fifth gear.

[star_deceiver]

Quote, originally posted by Old Tele man »...remember "back in the day" when people would simply bolt-on a Borg-Warner "Overdrive" unit in place of the original "tailshaft housing" to get better fuel economy at cruising speeds? Some were electric solenoid operated and others were manually engaged.3 on the tree with a push button!Quote, originally posted by -fluffy- »We don't have anything for the 08 and up cars, just the 02-07 Matrix/Vibe Ahh to have access to a CNC milling machine

[Esteban]

By " toying around " with this calculator, you can see a little difference a tire & wheel size can make. [ if it's possible to fit the new wheels ] http://www.miata.net/garage/tirecalc.html Don't forget, if it shows that your speedometer is now inaccurate, after a new size is installed, your mpg calculations will be inaccurate as well, & needs to be considered. Or, have speedometer recalculated. Yes, I am old enough to remember " bolt-on overdrive." && the overdrive lever you pulled from underneath the dash that many people called " freewheeling." For those with curious minds about the old overdrive units, here is a pdf file all about it. http://www.packardinfo.com/xoo...D.pdf

[-fluffy-]

I'm not a fan of oversized (or undersized) tires on passenger cars. Upping tire diameter is extremely limited in RPM drop benefits, and will make the speedometer inaccurate, which also voids your trip odometer and any mileage claims you may be making. Not to mention the added unsprung weight on the vehicle, which will increase resistance to acceleration, compromise handling, and lengthen stopping distances. Don't forget fender rubbing either.When I was running the desk at a local tire store, a man came in with a 99 Honda Prelude, and wanted my help determining how big of tires he could stuff onto the car, to lower the highway RPM, which he thought was far too high. I explained my logic behind the issue, and also explained that Honda designed the powertrain on his vehicle a certain way, to achieve the desired performance, and that his perceived "too high" RPM, was not only normal, but specifically set up that way.In regards to OE design and performance with our vehicles, yes, Toyota did design them a specific way, but that doesn't mean there isn't room for improvement. I feel that changing top gears on these cars, is the most simple, least expensive, and overall best way to increase efficiency. This type of modification works especially well on the 1ZZFE, due to its design and usable powerband, whereas other engines may not benefit.For its design and displacement, the 1ZZ has a rather low hp output, but also an unusually high torque output in relation to its hp and size. In the Vibe/Matrix, the 1ZZ is rated at 130 hp, and 125 lb ft of torque. Toyota designed the 1ZZ with two goals; torque and fuel economy. They accomplished it by using a small bore (79mm) vs. long stroke (91.5mm) setup, with a median 10.0:1 compression ratio.So, due to the 1ZZ's high torque level, and broad RPM range to use it in, the taller top gear hasn't negatively affected highway driving on the test car, which is stock just for reference.

[vibolista]

Since my tire is 4% larger than the OE tire, I do figure that 4% into mileage calculations. Same with the Speedo. Most speedometers have inaccuracies built right in, anyway. Use a good GPS or do the old fashioned stop watch routine on a measured mile at 60 mph to see what I mean. Few cars have speedometers that are spot on accurate. Road and Track published speedo error on cars they tested.The rest, fender rubbing... none, compromised handling... not, stopping distance... I can't tell the difference from the original RS-A. Ride is much better and quiet. The increased weight is negligible, a couple of lbs per corner, and I'm still getting 37 to 40 mpg. You may have a point on acceleration, but I don't drag the Vibe, so I haven't measured that.

[Kincaid]

As far as changing the weight of the tire, I would think much more weight would be added by putting a proper-sized 19 or 20 inch wheel with super low profile tires - that really puts heaviness out toward the rim.This is why some people that mod Hondas swear by small wheel sizes.

[Esteban]

I had a friend who changed the wheels & tires out on his Suzuki Samurai. I don't remember what size he went to,[ maybe 31" or more ] but the rig would burn up the clutch quickly, just getting it to move ! You cannot increase size but just so much.Maybe the factory 17" wheels with some different tire combination would help a little.

[-fluffy-]

The 16" wheels with OE size 205/55/16 are the best all around for these cars. Just be sure to have a nice all season tire, with low rolling resistance, and whatever you do, steer clear of the Goodyear RSAs. Awful tires.PS: I have pretty extensive tire knowledge, having worked in the industry, and would be happy to recommend some good tires if anybody needs them.

[PlatinumVibe08]

Quote, originally posted by -fluffy- »The 16" wheels with OE size 205/55/16 are the best all around for these cars. Just be sure to have a nice all season tire, with low rolling resistance, and whatever you do, steer clear of the Goodyear RSAs. Awful tires.PS: I have pretty extensive tire knowledge, having worked in the industry, and would be happy to recommend some good tires if anybody needs them.Ross,You sound credible and there are always tons of tire questions here ---> http://forums.genvibe.com/zeroforum?id=4 Looking forward to your input and good luck to you and your dad with the new gear set.PlatinumVibe08

[bikeman1]

This mod is potentially pretty cool. Living in the mountains, it is not for us in our 2007 because of the numerous steep highway grades on I-70 and I-68 across the mountains (we acquired our 2009 2.4L for that very reason). We already downshift in some cases to 3rd on long hills, and this would lower the ceiling of grades that would have to be dealt with. But if I lived in many parts of the midwest and was at highway speeds a lot, this could be a great upgrade. 2450 rpm at 70 mph is cruising right along in overdrive....could have a real impactwould the same gearset also work for other Toyotas with the 1ZZFE? I assume that includes the Matrix and Corolla both, some Celicas, and I think the Chevy Prizm...the market would seem broader than just the Vibe....but as you say, it depends on the transmission setup. I am not sure what the disposition of the engine is now. It was unique among the FE series of Toyota engines to have been built in North America (Ontario and West By God Virginia!). The Ontario plant discontinued production in 2007 before the new Matrix/Vibe emerged. The plant in Buffalo, WV (pop. 1100) keeps a small portion of Appalachia above the poverty line. They had switched to GR (Highlander) engine production after the 1ZZFE was phased out. I don't know if it is still put in Corollas. I don't think the transmission on the Vibe 1.8's was made there though they did make automatic transmissionsAnyway, keep us posted on your progress. I am intrigued if there are any torque or other issues. You may even be able to get incentive funding!

[keithvibe]

This is good news, I just hope he comes back to update the thread. He hasn't been back since he posted this.

[vibolista]

Steep hills are going to force you to downshift anyway, the taller 5th gear would still work for the normal flat or slightlly enclined roads sections. The time spent at speed with lower revs should extend mpg... so you still win. Gentle driving habits and planning ahead make for improved gas mileage and save wear and tear on the engine, tranny, brakes, bushings, bearings and tires. So far with the conservative 4% gearing reduction provided by my 225/50 17's... I'm still getting close to that 40 mpg figure I like. Last tank was 39.4 mpg with a lot of mixed driving and around 3 days of A/C use.That taller 5th gear would be nice to have.

[Harsh]

I would not mind shifting more to save some green. I mean what the heck, you are going to be sitting there doing nothing anyway... If you did not want to shift, shoudl have bought an Auto...