PTFE is a solid which is added to engine oil and coats the moving parts of the engine.

However, such solids seem even more inclined to coat non-moving parts, like oil passages and filters. After all, if it can build up under the pressures and friction exerted on a cylinder wall, then it stands to reason it should build up even better in places with low pressures and virtually no friction.

This conclusion seems to be borne out by tests on oil additives containing PTFE conducted by the NASA Lewis Research Center, which said in their report, "In the types of bearing surface contact we have looked at, we have seen no benefit. In some cases we have seen detrimental effect. The solids in the oil tend to accumulate at inlets and act as a dam, which simply blocks the oil from entering. Instead of helping, it is actually depriving parts of lubricant".

 

That's in engine oil.

PTFE/teflon in gearboxes/diffs should be ok....so long as its not a DCCD or plated LSD.

Also Teflon+Lithium grease (for extreme pressure use...not bikes ) is supposed to be better than standard Lithium Moly.....which maybe food for throught if you want to try and strip down your wheelbearings (although it is thinner, so needs redoing more often)


edit; Actually on repacking wheel bearings it might be a good idea to strip them down and put in fresh grease anyway and make sure the dirt seals aren't letting in dirt/water (alot of work to get at them, mind).

 

Wouldn't a decent fully synthetic oil be better? After all if these additives were so good the oil companies would probably market them themselves. Reading the link in my earlier post Dupont (invetors of Teflon) took legal recourse to stop companies marketing Teflon as an beneficial oil additive.

 

Bloody forum timeouts

I totally agree about not using it engines; there is no need to add a friction reducing additive, the thing is lubrication in gearboxes is different to a engine; They don't have filters, sumps or much in the way of passageways and many don't even have oil pumps (well most don't, except the Impreza six speed, which does).

The bearings are often hardened steel roller/ball/roller thrust bearings, or tapered rollers, and all gears are usually constant mesh with baulk rings that use friction to sychronise the gear speeds on gear changes. Basically lots of metal rubbing on metal with oil splash-lubricated.

Whearas with a car engine use soft metal fluid bearings which actually run on a thin oil film. The only constant mesh gears found nowadays is in the oil pump itself and the splines in the variable valve timing sprocket, and only metal to metal contact is mainly found on thepiston rings, valve guides and cam lobes and followers/rockers...Camshaft wear is something Imprezas don't suffer from (although there are other engines that do).

So what I'm saying what is unsuitable for one application shouldn't be ruled out for another. As with gearboxes its lubrication depends on oil being splashed about and ther is lot of metal on metal contact. However certain parts do require friction to work; Thats why I say don't put it in a gearbox/diff with plated diffs (DCCD etc) which can contaminate the clutch packs.


The worst thing that can happen if its used in a gearbox without plated diffs IMHO is it reducing the effectiveness of the syncro cones and make them more slippery. Meaning the driver needs to rev-match better on gearshifts or put more pressure on the shifter. Although one could argue that using a less slippery lube makes the driver more lazy/less skilled with gear changing and causes more syncro wear as a result: Point to note here is Ford specified Dexron II (ATF hydraulic oil for use with wet-plate clutches) in early MTX75 gearboxes to aid gearshifting problems (baulking).....Was it coincidence the same gearboxes also suffered excessive syncro wear and failures? No doubt failures were caused by the less slippery ATF oil allowing drivers to make more bad/lazy gear changes causing premature syncro failure.

Molybdenum is also a friction modifying solid...often found in grease and gearbox oils, the main difference is its a bit more sticky. PTFE is a similar compound, and is sometimes added into off-the shelf gear oils and greases. (Dupont do sell PTFE+molybdenum blended greases that can be used as a substitute for plain lithium moly grease). You also see it used in engine/gearbox assembly lubes, however it shouldn't be used in long-term oil.

 

The only additive you need is redex for your fuel, I don't bother with other additives

 

You find need all those additives just use redex for fuel, that's all

 

Whether you drive a tiny hybrid or a three-ton SUV, chances are you can squeeze a bit more distance out of each gallon of fuel -- and at today's gas prices, an improvement of just one or two miles per gallon (MPG) can really add up. These ten fuel saving tips have served me well over the years, and they can help you improve your car's fuel economy and take some of the sting out of high fuel prices. Most of these tips will give you a very slight incr.
1. Slow down
One of the best ways to save gas is to simply reduce your speed. As speed increases, fuel economy decreases exponentially. If you one of the "ten-over on the freeway" set, try driving the speed limit for a few days. You'll save a lot of fuel and your journey won't take much longer. (Just be sure you keep to the right, so you won't impede the less-enlightened.)
2. Check your tire pressure
Under-inflated tires are one of the most commonly ignored causes of crummy MPG. Tires lose air due to time (about 1 psi per month) and temperature (1 psi for every 10 degree drop); under-inflated tires have more rolling resistance, which means you need to burn more gas to keep your car moving. Buy a reliable tire gauge and check your tires at least once a month. Be sure to check them when they are cold, since driving the car warms up the tires along with the air inside them, which increases pressure and gives a falsely high reading. Use the inflation pressures shown in the owner's manual or on the data plate in the driver's door jamb.
3. Check your air filter
A dirty air filter restricts the flow of air into the engine, which harms performance and economy. Air filters are easy to check and change; remove the filter and hold it up to the sun. If you can't see light coming through it, you need a new one. Consider a K&N or similar "permanent" filter which is cleaned rather than changed; they are much less restrictive than throw-away paper filters, plus they're better for the environment.
4. Accelerate with care
Jack-rabbit starts are an obvious fuel-waster -- but that doesn't mean you should crawl away from every light. If you drive an automatic, accelerate moderately so the transmission can shift up into the higher gears. Stick-shifters should shift early to keep the revs down, but don't lug the engine -- downshift if you need to accelerate. Keep an eye well down the road for potential slowdowns. If you accelerate to speed then have to brake right away, that's wasted fuel.
5. Hang with the trucks
Ever notice how, in bad traffic jams, cars seem to constantly speed up and slow down, while trucks tend to roll along at the same leisurely pace? A constant speed keeps shifting to a minimum -- important to those who have to wrangle with those ten-speed truck transmissions -- but it also aids economy, as it takes much more fuel to get a vehicle moving than it does to keep it moving. Rolling with the big rigs saves fuel (and aggravation).
6. Get back to nature
Consider shutting off the air conditioner, opening the windows and enjoying the breeze. It may be a tad warmer, but at lower speeds you'll save fuel. That said, at higher speeds the A/C may be more efficient than the wind resistance from open windows and sunroof. If I'm going someplace where arriving sweaty and smelly could be a problem, I bring an extra shirt and leave early so I'll have time for a quick change.
7. Back off the bling
New wheels and tires may look cool, and they can certainly improve handling. But if they are wider than the stock tires, chances are they'll create more rolling resistance and decrease fuel economy. If you upgrade your wheels and tires, keep the old ones. I have fancy sport rims and aggressive tires on my own car, but I keep the stock wheels with a good narrower-tread performance tire in the garage. For long road trips, the stock wheels give a smoother ride and better economy.
8. Clean out your car
If you're the type who takes a leisurely attitude towards car cleanliness -- and I definitely fall into that category -- periodically go through your car and see what can be tossed out or brought into the house. It doesn't take much to acquire an extra 40 or 50 lbs. of stuff, and the more weight your car has to lug around, the more fuel it burns.
9. Downsize or hybridize
If you're shopping for a new car, it's time to re-evaluate how much car you really need. Smaller cars are inherently more fuel-efficient, and today's small cars are safer and roomier than ever. And if you've never considered a hybrid, maybe it's time -- hybrids really do work, and new entries like Toyota's compact Prius c and SUV-sized Prius v the sporty Honda CR-Z make it easier than ever to find a hybrid you can live with.

10. Don't drive
Not a popular thing to say on a car site, I know, but the fact is that if you can avoid driving, you'll save gas. Take the train, carpool, and consolidate your shopping trips. Walking or biking is good for your wallet and your health. And before you get in your car, always ask yourself: "Is this trip really necessary?"
Performance Parts Online

 

Gas? You mean petrol we an't in America now lad

 

"stick shift".. we use Manual transmission here.. there is no woodwork in our gearboxes!

 

I tried a little experiment in my wrx wagon a couple of weeks ago just to see what mpg I could get when driven fairly sensibly, not exactly scientific but I achieved just over 28mpg by keeping the revs below 3000rpm, short shifting and block changing.

I got 315 miles from fuel light coming on, brimming the tank and driving my daily route to work of 16 miles of mixed 30mph villages to 60 mph country roads till the fuel light coming on again.

Then I thought, I didn't buy this car to worry about mpg, lifes too short!

 

Only 28mpg ? I can get 34.48mpg out of my 2000 turbo awd, granted its mostly 60mph roads, I shift gears between 2300 and 2800 rpm for fuel I use Tesco 99 Ron.

 

Interesting
Sub imp 330s 20.5 mpg av
Sub Cosworth 19mpg av
Good job the wife has VW Touran diesel
And it depends how you look at it if it's 'miles per gallon' you'll get depressed with your sub
If it's 'smiles per gallon' well there you have it - get a Subaru
Incidentely if you want to go all 'Eco' buy a road bike - I have - going down a hill at 40mph sucks up your nuts as much as any slippy slide sub stuff

 

just managed an alltime best of 33.59 mpg on an extended run down to southampton and back...nearly 450 mile round trip mostly at 70-80mph..quite chuffed with that considering its an auto

 

Travelling down& back to the Prodrive event i got 34mpg. The journey was done at 65-70mph

 

I managed 27.68, on that trip, in my GB270,

 

One thing I don't understand and I tested it, is that my impreza actually uses less fuel when driving faster.

 

Pumping losses Steve.

Any car has one power stroke to three using strokes. Your power stroke needs to drive the other three strokes, overcome the losses from the gearbox and diff and tyre deformation. And wind resistance, etc. What we forget is the induction stroke has to pull the air past any obstructions.

Take a 106/Aego/C12 type car. At 60mph, it needs maybe (guestimate) 11bhp to maintain that speed. The drivetrain probably needs 3bhp so that's 14. in 5th at 2,500rpm, it probably only makes 16bhp on full throttle. So the throttle is mostly open. If you want to accelerate you need to change down to spin the motor.

Now, the induction stroke is pulling nearly a full cylinder full past a nearly open throttle, past an air filter and hot wire MAF. Not a lot of restriction there. `/2hp perhaps. So our engine needs to make 14.5bhp to get the 11 to the road and burns fuel to achieve this.

You can guess the rest. Our 4x4 drivetrain probably takes 10hp, our turbo, intercooler, MAF and filer all add up. Our wide tyres as well.

But. If our be-winged flared scoop equiped cars need 15 hp to maintain 60mph. , that's now 25 bhp plus what's needed to suck the air passed the throtlle. But our cars make 150 or so at 60mph and 2,700rpm. So the throttle is nearly closed. Maybe 10hp worth of pumping losses just there.

SO to put the 15hp to the road we need to make 35hp, and so burn fuel for that. 14.5 vs 35, probably explains his 50mpg vs our 23-24mpg pretty well.

If you go faster, your throttle is open more and your losses are less, in theory you want to open your throttle as much as you can without getting boost, so low revs works.

Of course, if our cars has solenoid operated valves and no cams/throttle plates, etc it would be better. All electric drive with four synchronous AC motors instead of diffs and gearboxes even better.

Until then, it's just watch the boost gauge time.....

 

Or save 5.00 a time by not bothering. Petrol is an effective cleaner. Fuel system cleaners are a gimmick at best.

 

Just think of the accelerator as a tap

 

this is an interesting one for me, as im still considering which to go for, import or uk spec (classic)

can I ask, those who are getting mid late 20's with carefull off the boost driving, are your cars modified in the engine department in any way, eg bigger turbo/injectors re maps etc?

 

My type r is listed as 18mpg if I recall correctly . . with a few mods on mine im getting about 15mpg combined

 

its easy do what i do dont work in miles per gallon cos its depressing work in smiles per gallon and youll get a nice high number. or just drive sensible but god its hard ive got a very heavy right foot lol

 

folowing figures can be easily achieved even with slightly hard foot.

impreza STI 03 blob (turbo) - 25mpg
impreza gx 04 blob (n/a) - 35mpg
forester s-turbo 01(turbo) - 30mpg

please note these cars that i am giving the figures for are not modified in any way. i have personally achieved these figures with those cars.

 

Me and the missus drive our forester s turbo as our daily.Its comfortable and moves quick enough

 

In my totally standard Bugeye WRX MY2001 with 137K miles so far, the average recent fuel consumptions have been in the 30-36MPG range - mixed driving (local and long distance and some faster driving) - using Shell V Power and plus factor has been higher ambient temps, hence quicker engine warm up. Averages in colder months had been 28-33MPG. My driving style must be a factor - I try to always anticipate traffic and road ahead - hang back to avoid needless braking and then subsequent acceleration and gear changing.

 

well ive got a 2000 jdm bug quite modified tdo5 20g running near 400 bhp on 2.5 engine and im no where near that. if i get 20 mpg im impressed, ive had it down to single figures when im ragging it, but saying that i dont commute to work so its literally a weekend car so not so bothered about mpg. i agree that they can be driven economically with a little care, but the "go" pedal is more fun lol

 

I normally average around 28mpg, dosn't seem to change much no matter how slow i go.

 

All I know I just did 338.6 miles one £70 of v power...