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Engine and axle ratio modifications for mileage and power gains


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OK all I am going to make this a sticky. There is a ton of things we can possibly do to the 22 and V6 engines and drive trains for MPG and HP/Torque gains. There are big differences between the 22 and V6 transmissions, 22 no locking torque converter (except 22re turbo) and V6 has a locking torque converter.

Here is a list.
Air filters
Cold air intake systems
Spark plugs
Higher voltage coils
Larger exhaust including catalytic converters
Camshafts
Engine oil and additives
Transmission coolers
Larger radiators
Tire sizes
Rear end gear ratio changes
Actual MPG numbers. We are not all in Kansas where it is flat forever! Don't forget weight, coach length and cargo.
Sure I missed something.

Have at it, all opinions and scientific facts need apply.

Oh, forgot one thing, drafting behind an 18 wheeler, it does work!

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17 hours ago, Gulfstream Greg said:

Oh, forgot one thing, drafting behind an 18 wheeler, it does work

The only problem with that is your depending on the driver in front. I rather sacrifice a little mpg and depend on my own eyesight and reflex. You hit from behind, it's going to be your fault.

 

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The Exhaust Gas Recirculation system reduces the combustion temperature of the engine and therefore reduces the efficiency and horsepower of the engine. The goal is to produce less NOx gases which can create ozone when reacting with sunlight.

Those of us outside an air attainment region don't need NOx reduction.

According to Toyota, the EGR is reduced at idle and light engine loads but is increased with higher engine load. If the EGR is not functioning, there is a risk of detonation. The ECU will reduce timing advance if it senses lack of EGR.

Being able to retune the ECU to max mileage, similar to the VW cheat method, might be the way to go.

 

 

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16 hours ago, fred heath said:

The only problem with that is your depending on the driver in front. I rather sacrifice a little mpg and depend on my own eyesight and reflex. You hit from behind, it's going to be your fault.

 

Very true and probably illegal. Only ever drafted once. Was driving north on Highway 101 in CA against a 30 mph head wind. I was driving the turbo sunrader. All by myself I really had to have my foot in it and was running max boost of about 7 pounds and about 50 mph. A truck got onto the freeway in front of me and I fell in behind. Boost almost dropped to zero with allot less foot in the pedal. Ran like that for about 40 miles. The trucker moved to the other lane to pass a slow car. I hesitated. Never could catch back up once I was back in the head wind. 

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In California big rig speed limit is 55 and some drivers actually obey it. Much safer to draft at that speed. I've had some very good results staying behind trucks. I also think our rigs would benefit more that that chart since wind effects us so much more than cars

Linda S

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At 55 mph your traveling at approximately 80 fps (feet per second). The normal reaction time for a well rested, alert, non-distracted driver is approximately 3/4 second between your brain telling your foot to hit the brake, and actual activation of the brake. This means your vehicle has traveled a total of 60 feet. If your closer than 60' to the vehicle in front of you, chances are you will have contact.

 

 

In addition, a whole new set of factors come into play. Toyota mhs have notoriously small brakes in comparison to the amount of weight they have to stop. Chances are that TT with air/hydraulic brakes on all 10-14 travel wheels will stop much faster than your toy. So even if you try to make the argument your both traveling at the same speed your still on the deficit side.

Personally, the potential risk to my mh is not worth the savings in time and fuel by drafting.

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" In road tests, the testers achieved an almost 20% improvement in gas mileage at a distance of 100 feet (at 55 mph) and a 45% improvement at 10 feet."

" The recommended distance at 55 miles per hour is 150 feet."

" Conclusions: there are better ways to save fuel."

http://www.treehugger.com/cars/drafting-behind-trucks-does-it-work.html

myth2.jpg

http://www.autoblog.com/2007/10/28/mythbusters-drafting-10-feet-behind-a-big-rig-will-improve-mile/

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  • 3 years later...

I'd be interested to hear if anyone did the rear differential upgrade to 4.88 gears in the V6

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  • 1 year later...
On 4/5/2017 at 3:55 PM, fred heath said:

The only problem with that is your depending on the driver in front. I rather sacrifice a little mpg and depend on my own eyesight and reflex. You hit from behind, it's going to be your fault.

 

what's worse imo is when a car follows you refusing to pass effectively drafting you and slowing you both to the point you are now under the speed limit and impeding traffic until you have to pull over.  i want to make a light up sighnion back says "PASS WITH CARE" that flashes when i turn it on.   but i love getting a good draft on a semi or other rv and will sometimes ask other travelers permission to draft them at rest areas

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Your not impeding traffic unless there is no way for them to pass. If on a two lane road and the other driver can't pass it's not illegal to imped traffic if the incline doesn't allow you to go faster. Think big rigs going into the mountains. I do use pull outs when I can find them. If your on a big highway I just slow down so they get so irritated they finally pass. I've seen a few funny signs like " I'm peddling as fast as I can"

Linda S

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  • 9 months later...

I have gone through the cylinder heads on our ‘91, and replaced the exhaust valves, springs with oem parts to be able and regain the ability to have a proper adjustment using the (limited) available shims. 
At the same time, I modified the intake ports, mostly on the roof, around the guide bosses. Also took the time to unshroud the exhaust valves in the chambers, and polish the chambers, relieving the sharp edges.

 

After doing some research, I determined that the original injectors may be struggling after the headwork and exhaust modifications. I chose a 20% larger set of injectors instead of messing around with raising the fuel pressure.

The new injectors also have multiple nozzles vs the original ones, for improved atomisation.

 

The exhaust was changed to eliminate the congestion around the number 6 cylinder. This involved making a full sized mock up of the obstacles and making a few trips to a good exhaust shop nearby. The result is now dual 2-1/4” down pipes that merge just ahead of the original catalyst flange. No egr now either.

The rest of the system is a Pace setter with an additional resonator, and more straight tubing to accommodate the longer wheelbase.

 

The rig drives great after a few drive cycles in order for the system to acclimate itself.

A gauge hooked up to the O2 sensor indicates proper mixtures, and if it had more power at open throttle, I would be concerned for the transmission’s life expectancy.

 

Next is to make some distance runs at freeway speeds and check the gas mileage, maybe do some tuning if part throttle isn’t optimal on long hills.

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Some pictures of the process.

the ones that are white pvc were part of the prototyping.

This would have been much much easier had the rig been able to travel to the muffler shop. Sorry that most of the images load upside down…54CFA777-F00D-4052-8DE8-9268E35620FE.jpeg.e074ec45bd11ff4a6dd375384003e076.jpegEDE10A9E-EA7E-422B-8446-FC3E3FE34E6B.jpeg.2c2ff5515eb5a8a73aa8cde6356ee943.jpeg3466CC9D-FE5A-4BD7-9E99-5457D8070A49.jpeg.bc89540e521922f2cc79846e2ffef228.jpeg

19147162-A768-4400-9DC9-CC58B5B84024.jpeg

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Looks good. I too have the 3.0 3VZE engine. When I did a head rebuild I removed some exhaust restrictions. It breathes much better. Exhaust dumps out right behind the cab. Engine seems to run cooler too. Wish I had changed my injectors also. 

IMG_20200331_160127145_HDR.jpg

IMG_20200331_160141459_HDR.jpg

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The injectors I used were from a ‘90s 2.2  Camry.

These really need help in the exhaust, not typical to have engines die prematurely because of it.

 

 I’ll bet that sounds much better now.

 

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hey I don't mean to hijack your post. but i see that photo you posted of the clear shot of your leaf spring that shackle looks new. did you replace them? i was thinking of replacing mine with some a little longer to give me a inch or so lift in the rear. 

 

 

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Those shackles are just some 3/8” x 1-1/2” steel flat bar I had here and drilled them to match the junky ones that came on it. I found the grade 8 bolts at an industrial hardware store.

They are 5-1/2” eye to eye, same as the ones that came out, and used a polyurethane bushing kit.

 

Also have an airbag setup on there too, highly recommended, can adjust to your situation.

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