For the extra I'll spend on gas with the sticky tires vs the old ones...I could have bought another set of the same tires...but then the difference between the sticky ones and the old ones was like night and day as far as handling.
Next set will be a compromise.
Loss of Power at altitude
Due to histeresis, the rolling radius and the rolling circumference are not strictly proportionnal. More or less you should use 3.05 instead of 3.14159... for Pi.3A-C Power wrote: Though they are not perfectly equal in the rolling radius, many different size tires came with the Tercel in different places. In particular 13" came in 145, 155, 165 and 175, and 14" in 175 and 185 width.
Each tire from each brand have different flange stiffness and so different "Pi values".
Due to centrifugal effect, this Pi value also changes with current speed.
Differences are reduced with very low profiles.
As I wrote it, we here are not allowed to change the rolling circumference (+/-1%) that would change the precision of the speedometer, the suspension's geometry (and even the taxes for some models !!!).
We all have tables with the true values for each brand in order to know witch different-sized tires you may fit.
Good Year also made "marketing sizes" with graved numbers bigger than the true measurable dimensions... !
145-155-165-175-etc... No matter the width you choose, if you change also the flange height to keep the same circumference.
Thin for snow, large for sand or mud. Thin for speed, large for lasting etc...
Some good info in your post.....
Do you have specific info on brands of tires that have been tested in the EU to have lower rolling resistance...I know you mentioned a Michelin tire.
In the US...the OEM tires as sold on cars tend to have low rolling resistance due to the OEMs trying to meet mileage standards...but they generally have poor traction.
They don't really rate tires according to MPG potential.
To me it's also a matter of economics...makes little sense to buy expensive tires with low rolling resistance if the money you save on gas is equivalent to the increased tire cost.
Do you have specific info on brands of tires that have been tested in the EU to have lower rolling resistance...I know you mentioned a Michelin tire.
In the US...the OEM tires as sold on cars tend to have low rolling resistance due to the OEMs trying to meet mileage standards...but they generally have poor traction.
They don't really rate tires according to MPG potential.
To me it's also a matter of economics...makes little sense to buy expensive tires with low rolling resistance if the money you save on gas is equivalent to the increased tire cost.
Give a boy a gun-give a biatch a cell phone-and pretty soon you almost got yourself a police state.
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
Brands don't communicate about rolling resistance with "good" numbered datas... That would be hard to suffer for some ones.
For comparisons, we would need a correct norm about tests circumstances as the resistance changes with pressure, load, temperature etc...
Few press-tests were technically corrects, with many numbered datas.
More, it's "easy" to make a low resistance tire, it's far harder to save a good grip. Eternal compromises... I mean it's no right to compare a good fuel-saver soap with a correct compromise.
Here, a standart summer tire has about a 0.015 (1.5%) rolling ratio. The siliced Michelin "X-green" are under .01 (1%) are have equal grip. The just are more expensive.
Truck tires are lower but have special structure, special patterns and are not availaible in touring sizes.
MPG benefits can be got when air drag isn't proportionally too important, so up to 50mph. If you ever drive above (as I do) you won't note improvement.
My car-carrier trailer went new with awfull south-corean tires. I change them for X-green. When I use it with big load and slow speed, I note a great economy.
You can calculate your current rolling ratio with the following test.
You shift neutral on a flat road (no wind) and chrono the time from one speed to another. Do the same test from a higher speed to another. Knowing the real weight of you and your car you can resolve a "system of two second-degree equations" (right term for two "Y=AX²+BX+C" ??) and so know the true rolling ratio and true aero SCx of the body.
Then you'll know for example that a bigger tire will lead more rolling resistance AND also more air drag (Cx). If you make a custom spoiler, you'll know if it's better or worse without driving too long.
Of course, a fifth wheel, a radar or a GPS is easier and more precise to calculate deceleration than dash's speedometer + hand-chrono.
For comparisons, we would need a correct norm about tests circumstances as the resistance changes with pressure, load, temperature etc...
Few press-tests were technically corrects, with many numbered datas.
More, it's "easy" to make a low resistance tire, it's far harder to save a good grip. Eternal compromises... I mean it's no right to compare a good fuel-saver soap with a correct compromise.
Here, a standart summer tire has about a 0.015 (1.5%) rolling ratio. The siliced Michelin "X-green" are under .01 (1%) are have equal grip. The just are more expensive.
Truck tires are lower but have special structure, special patterns and are not availaible in touring sizes.
MPG benefits can be got when air drag isn't proportionally too important, so up to 50mph. If you ever drive above (as I do) you won't note improvement.
My car-carrier trailer went new with awfull south-corean tires. I change them for X-green. When I use it with big load and slow speed, I note a great economy.
You can calculate your current rolling ratio with the following test.
You shift neutral on a flat road (no wind) and chrono the time from one speed to another. Do the same test from a higher speed to another. Knowing the real weight of you and your car you can resolve a "system of two second-degree equations" (right term for two "Y=AX²+BX+C" ??) and so know the true rolling ratio and true aero SCx of the body.
Then you'll know for example that a bigger tire will lead more rolling resistance AND also more air drag (Cx). If you make a custom spoiler, you'll know if it's better or worse without driving too long.
Of course, a fifth wheel, a radar or a GPS is easier and more precise to calculate deceleration than dash's speedometer + hand-chrono.
Last Sunday I went uphill as the trip I related on Jan 8th.
All conditions were equal except :
wether a bit colder
-20° advanced timing instead of -10°
NO acetone in gas.
Total, I got 7,45L/100 so 31.5 MPG
I didn't feel the nice additional torque at low revs and high vacuum as I felt with acetone.
I had some knock at WOT, but I just depressed so much once or twice to escape a hard pass.
Could the acetone alone be responsible for this 15% saving ?
I'll try next time WITH acetone to compare...
All conditions were equal except :
wether a bit colder
-20° advanced timing instead of -10°
NO acetone in gas.
Total, I got 7,45L/100 so 31.5 MPG
I didn't feel the nice additional torque at low revs and high vacuum as I felt with acetone.
I had some knock at WOT, but I just depressed so much once or twice to escape a hard pass.
Could the acetone alone be responsible for this 15% saving ?
I'll try next time WITH acetone to compare...
I performed another test.
Nevers-Versailles and back in the day.
Cold whether, 4" of snow in the morning, dry for the return.
The engine is still so worn of course.
New plugs, new points and condensator, -15° advanced timing.
0,3% acetone.
100Kph average (in the snow! wahoo!) in the morning, a bit less for the return.
Total 567Km/37L80 so 6,66 L/100Km or 35,3MPG
I think that without acetone it would have demand 1L/100 more (4 or 5 MPG less) That's about a 15% economy.
Nevers-Versailles and back in the day.
Cold whether, 4" of snow in the morning, dry for the return.
The engine is still so worn of course.
New plugs, new points and condensator, -15° advanced timing.
0,3% acetone.
100Kph average (in the snow! wahoo!) in the morning, a bit less for the return.
Total 567Km/37L80 so 6,66 L/100Km or 35,3MPG
I think that without acetone it would have demand 1L/100 more (4 or 5 MPG less) That's about a 15% economy.
Wondering if you are getting a CONSISTANT 15% MPG gain with the acetone at 0.3%?retroloc wrote: I performed another test.
Nevers-Versailles and back in the day.
Cold whether, 4" of snow in the morning, dry for the return.
The engine is still so worn of course.
New plugs, new points and condensator, -15° advanced timing.
0,3% acetone.
100Kph average (in the snow! wahoo!) in the morning, a bit less for the return.
Total 567Km/37L80 so 6,66 L/100Km or 35,3MPG
I think that without acetone it would have demand 1L/100 more (4 or 5 MPG less) That's about a 15% economy.
Are you getting any power gains from using the timing advance? Acetone?
I've been using a stopwatch to time from 30 MPH to 55 MPH in 5th gear...no shifting. I use the same stretch of relatively flat road (country road)...need to try to have same outside temp....no wind. Get going at 30 MPH...then floor it and time to 55 MPH.
It took at least 20% less time with advanced timing vs OEM timing.
35 MPG is very good for winter driving.
Give a boy a gun-give a biatch a cell phone-and pretty soon you almost got yourself a police state.
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
Consistant is also a french word but should mean something else...
'didn't understand.
The OEM setting (-7°) is choosen for ordinary gasoline (most Heptane at about 82 ocatnes) that's no longer availaible in the pump stations.
Using the poorest octane availaible (95) is logical to raise the advance.
I tried -20° but came back to -15° because I had some knock (ping) when climbing with a trailer.
I didn't try if I could tune to more advance with acetone. -15° is OK for common gasoline.
"35 MPG is very good for winter driving"
+/-...
A new run-in car with summer tires should get 45.2MPG at 56Mph constant according to '83-'84 datas
With restored compressions I think I could get 40MPG with my winter tires (I keep them all year long).
The gains with acetone is easily noticeable. I can go across a village holding the 6th at 30-40Mph and raise back to 50-60Mph quite without depressing gas pedal. At 60Mph the carbs'butterfly is quite fully closed. In good conditions (fresh whether) I can drive up to 140Kph (85-90mph) on the first barrel, without "econonomy light" on.
Next Saturday I have to pick up another car across the mountain.
It'll be ... heavy ! A former Saab 900Turbo + a spare engine + 8 spare wheels + my trailer so about 2tons to drag... I hope there isn't too much snow (last wheek the highway was CLOSED!).
I'll post my mileages on monday !
My Tercel is fantastic... !
'didn't understand.
The OEM setting (-7°) is choosen for ordinary gasoline (most Heptane at about 82 ocatnes) that's no longer availaible in the pump stations.
Using the poorest octane availaible (95) is logical to raise the advance.
I tried -20° but came back to -15° because I had some knock (ping) when climbing with a trailer.
I didn't try if I could tune to more advance with acetone. -15° is OK for common gasoline.
"35 MPG is very good for winter driving"
+/-...
A new run-in car with summer tires should get 45.2MPG at 56Mph constant according to '83-'84 datas
With restored compressions I think I could get 40MPG with my winter tires (I keep them all year long).
The gains with acetone is easily noticeable. I can go across a village holding the 6th at 30-40Mph and raise back to 50-60Mph quite without depressing gas pedal. At 60Mph the carbs'butterfly is quite fully closed. In good conditions (fresh whether) I can drive up to 140Kph (85-90mph) on the first barrel, without "econonomy light" on.
Next Saturday I have to pick up another car across the mountain.
It'll be ... heavy ! A former Saab 900Turbo + a spare engine + 8 spare wheels + my trailer so about 2tons to drag... I hope there isn't too much snow (last wheek the highway was CLOSED!).
I'll post my mileages on monday !
My Tercel is fantastic... !
By "consistant"....I mean is your mileage about the same for each tank that you use acetone?
With another car that I tried acetone in last summer...I would see a good MPG gain...and then the next tank it would be back to the original MPG.
I haven't tried acetone in the Tercel due to using heated fuel...where I get around an 10-11% gain.
I'm going to set the heated fuel up so that it can be shut off and the heat regulated this spring...IF it ever gets here....outside temps about 10-15F below normal.
With another car that I tried acetone in last summer...I would see a good MPG gain...and then the next tank it would be back to the original MPG.
I haven't tried acetone in the Tercel due to using heated fuel...where I get around an 10-11% gain.
I'm going to set the heated fuel up so that it can be shut off and the heat regulated this spring...IF it ever gets here....outside temps about 10-15F below normal.
Give a boy a gun-give a biatch a cell phone-and pretty soon you almost got yourself a police state.
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
Yet the '86 test you mention elsewhere shows 33 MPG at 56 MPH?retroloc wrote: A new run-in car with summer tires should get 45.2MPG at 56Mph constant according to '83-'84 datas
Shows the MPG results of emissions equipped cars?
Hope you have BRAKES on that trailer........
Give a boy a gun-give a biatch a cell phone-and pretty soon you almost got yourself a police state.
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
No emission stuff on a '86. Engines under 2000cc had their first cat' on 1/1/1993.
33Mpg were tested on their own by a magazine. maybe with a "too young" engine.
45.2Mpg were tested by an public agency on a run-in '83 model. Brands are allowed to use these "official" datas in their adds.
I have brakes on my trailer. I never use them
. The braker is a coward
Here what I reported on another forum (I'll translate if I have time)
<<Merci pour tes voeux de bon voyage.
Ca ne s'est pas si mal passé...
D'abord parceque la tractrice chantait fort et clair. Je veux dire qu'elle ne peut offrir que ce qu'elle a mais qu'elle y a mis la meilleure volonté du monde, aucun pauvre cheval ne manquait àl'appel. (la précédente fois où j'étais àpeu près aussi lourd, l'allumage n'était pas tip-top, c'était un désagrément de plus)
Ensuite parceque la Saab était trop centrée àl'avant. C'était un inconvénient pour bien laisser coulisser le frein mais par contre ça m'a assuré une stabilité en ligne droite bien reposante. Jusqu'à105Km/h en descente (j'ai pas tenté le diable au delà, la remorque étant moitié plus lourde que la tractrice...)
Mais P*** c'était lourd... Une Saab "blindée" avec deux moteurs et 9 roues... Pour grimper àLodève: 3500tr en 1ère tout du long... A 2000tr en 2ème elle était près de s'asseoir et les pompes àeau et huile ont un débit bien moindre. Tu as entendu mon silencieux... en haut dans le tunnel, je ne me suis pas privé de descendre ma vitre, au moins ça m'occupais !
A Millau j'ai pris la ville pour ravitailler et je suis ressorti de la cuvette comme une fleur, à55-60 en 2ème dans un barouf sonore qui avait pour lui de sonner juste et clair.
Les decentes étaient pas mal aussi: La Fageolle par exemple c'est 6% pendant 12Km... 3ème en haut, tu lâches tout et tu te tapes 10 minutes àplus de 4000tr sans n'avoir jamais touché l'accélérateur. A ce compte làj'ai dû descendre àpeu près 1 litre d'huile aux 1000Km sur l'aller et le retour..
Sur la fin, en plaine, c'était quand même plus naturel. Le brave 1400 rincé de compression emmenait quand même tout l'ensemble à85-90 en 5ème.
Total une petite journée d'une vingtaine d'heures... >>
33Mpg were tested on their own by a magazine. maybe with a "too young" engine.
45.2Mpg were tested by an public agency on a run-in '83 model. Brands are allowed to use these "official" datas in their adds.
I have brakes on my trailer. I never use them
. The braker is a coward Here what I reported on another forum (I'll translate if I have time)
<<Merci pour tes voeux de bon voyage.
Ca ne s'est pas si mal passé...
D'abord parceque la tractrice chantait fort et clair. Je veux dire qu'elle ne peut offrir que ce qu'elle a mais qu'elle y a mis la meilleure volonté du monde, aucun pauvre cheval ne manquait àl'appel. (la précédente fois où j'étais àpeu près aussi lourd, l'allumage n'était pas tip-top, c'était un désagrément de plus)
Ensuite parceque la Saab était trop centrée àl'avant. C'était un inconvénient pour bien laisser coulisser le frein mais par contre ça m'a assuré une stabilité en ligne droite bien reposante. Jusqu'à105Km/h en descente (j'ai pas tenté le diable au delà, la remorque étant moitié plus lourde que la tractrice...)
Mais P*** c'était lourd... Une Saab "blindée" avec deux moteurs et 9 roues... Pour grimper àLodève: 3500tr en 1ère tout du long... A 2000tr en 2ème elle était près de s'asseoir et les pompes àeau et huile ont un débit bien moindre. Tu as entendu mon silencieux... en haut dans le tunnel, je ne me suis pas privé de descendre ma vitre, au moins ça m'occupais !
A Millau j'ai pris la ville pour ravitailler et je suis ressorti de la cuvette comme une fleur, à55-60 en 2ème dans un barouf sonore qui avait pour lui de sonner juste et clair.
Les decentes étaient pas mal aussi: La Fageolle par exemple c'est 6% pendant 12Km... 3ème en haut, tu lâches tout et tu te tapes 10 minutes àplus de 4000tr sans n'avoir jamais touché l'accélérateur. A ce compte làj'ai dû descendre àpeu près 1 litre d'huile aux 1000Km sur l'aller et le retour..
Sur la fin, en plaine, c'était quand même plus naturel. Le brave 1400 rincé de compression emmenait quand même tout l'ensemble à85-90 en 5ème.
Total une petite journée d'une vingtaine d'heures... >>
Some new datas about acetone...
First I checked my odometer. With my current 175/70-13 M+S it's 6.663% wrong. I mean when I drive 169 Km according to milestones I read 180.2Km. All fuel consumptions above must so be increased by 6.663%.
The following numbers aren't fully "scientifics" because they compare different trips at different speeds but they give an idea.
I live in the valley, I fetch a car at sea side, across the mountain.
1st tank:
Nevers-Millau, the trailer is empty, I try to go fast. I pass some passes at 60Kph (37mph) on 3rd. Up to 140Kph (87mph) in downings. 86Kph (53mph) average. 0.3% acetone. 416Km. 10L3 per 100Km according to odometer, 10L99 "true" so 21.4MPG
2nd tank:
Millau-Millau, the trailer is empty half the way (downings) and loaded (2Tons !) the way back. Several passes, at 30Kph (19mph) on 1st all climb long. About 55kph average (34mph). 0% acetone. 246Km. 9L75 "odo" so 10L40 "true" or 22.6MPG
3rd tank:
Millau-Issoire. Loaded trailer, only mountain, 0.15% acetone. 208km. 10L70 "odo" so 11L41 "true" or 20.6MPG.
4th tank:
Issoire-Nevers. Loaded trailer, mostly 85-90Kph in 5th. 0.1% acetone. 211Km. 10L06 "odo", so 10L73 "true" or 21.9MPG.
In another trip (with an ignition trouble) and a quite so heavy trailer I noted:
12L18 "odo" so 12L99 "true" or 18 mpg in one way with 0.3% acetone and 11L49/12L25 or 19.2MPG with 0%.
All in all I think that acetone can lead benefits if you drive at low charge (high vacuum) as Americans do (big engines, slow revs, auto trans with overdrive, slow spped...) and can be worse in economy at high charge (Wide Open Throttle).
I have to re-do a slow trip without trailer and without acetone to confirm...
First I checked my odometer. With my current 175/70-13 M+S it's 6.663% wrong. I mean when I drive 169 Km according to milestones I read 180.2Km. All fuel consumptions above must so be increased by 6.663%.
The following numbers aren't fully "scientifics" because they compare different trips at different speeds but they give an idea.
I live in the valley, I fetch a car at sea side, across the mountain.
1st tank:
Nevers-Millau, the trailer is empty, I try to go fast. I pass some passes at 60Kph (37mph) on 3rd. Up to 140Kph (87mph) in downings. 86Kph (53mph) average. 0.3% acetone. 416Km. 10L3 per 100Km according to odometer, 10L99 "true" so 21.4MPG
2nd tank:
Millau-Millau, the trailer is empty half the way (downings) and loaded (2Tons !) the way back. Several passes, at 30Kph (19mph) on 1st all climb long. About 55kph average (34mph). 0% acetone. 246Km. 9L75 "odo" so 10L40 "true" or 22.6MPG
3rd tank:
Millau-Issoire. Loaded trailer, only mountain, 0.15% acetone. 208km. 10L70 "odo" so 11L41 "true" or 20.6MPG.
4th tank:
Issoire-Nevers. Loaded trailer, mostly 85-90Kph in 5th. 0.1% acetone. 211Km. 10L06 "odo", so 10L73 "true" or 21.9MPG.
In another trip (with an ignition trouble) and a quite so heavy trailer I noted:
12L18 "odo" so 12L99 "true" or 18 mpg in one way with 0.3% acetone and 11L49/12L25 or 19.2MPG with 0%.
All in all I think that acetone can lead benefits if you drive at low charge (high vacuum) as Americans do (big engines, slow revs, auto trans with overdrive, slow spped...) and can be worse in economy at high charge (Wide Open Throttle).
I have to re-do a slow trip without trailer and without acetone to confirm...
I tink I've noticed the same thing...better MPG if you go easy...more power if you need it.....be interesting if you could try the 30 to 55 MPH or a similar test with and without acetone. Might test this myself this summer.
Give a boy a gun-give a biatch a cell phone-and pretty soon you almost got yourself a police state.
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
No. I feel more torque if I drive with few throttle, but I feel it worse when I demand the max. When I floor it I feel it drags worse than with pure gasoline, and I check that with worse mileages.takza wrote: I tink I've noticed the same thing...better MPG if you go easy...more power if you need it...
If I perform your 30-55 test at WOT, I think it would be better without acetone than with it.
I'm going to try testing it this summer...maybe you have too much ignit advance for use with acetone? .3% acetone MIGHT require retarding the advance some from where it runs best with straight gas? Just guessing though.
With some engines you don' t really get ping as you do with a Tercel...you just notice rougher running...along with a falloff in power...when you advance too far. Maybe with the Tercel...somewhere below pinging level is best?
With some engines you don' t really get ping as you do with a Tercel...you just notice rougher running...along with a falloff in power...when you advance too far. Maybe with the Tercel...somewhere below pinging level is best?
Give a boy a gun-give a biatch a cell phone-and pretty soon you almost got yourself a police state.
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...