Dear ALL
I have the 2009 Chevrolet Aveo ( Daewoo Gentra ) . manual 1.5 L with 83 bhp. I was happy with it but I suffered alot from the so weak performance generated by the 1500 CC SOHC engine . so I started many projects to develop this engine and tune my car
stock performance accelaration : 0-100 in 15 sec
after installing
1- INJEN cold air intake system with Long ram style
2- MSD 8.5 Super conductor wires
3- PULSTAR pulse plugs with iridium tip
4- electrical super charger
0-100 acceleration in 12 sec
note that all that happens after installing the Cold Air Intake only . no better results after installing the wires , spark plugs and electrical super charger
I was shocked after all that money I payed on the performance parts with no results at all
need to know what to do?
what did I do wrong?
note that all parts installed in another car EG . Nissan Sunny ( Almera , Sentra ) 1.6L Dohc with auto trans . made a major diffrence in performance . so I have a very bad thing in my system and I need to know
thanks
What is wrong with my 1.5L engine?
Moderators: daewoomofo, Moderators Group
What is wrong with my 1.5L engine?
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Re: What is wrong with my 1.5L engine?
see my other post about plugs and wires
and "electrical superchargers" are a huge waste of money, if you take it out you may find performance increases
a little electric fan running +12v and a handful of amps will never provide positive pressure
if you wanted a true electric supercharger you would need a motor about the size of a electric leaf blower that runs at 240v and then 10x 24v batteries wired in series in the boot plus around 15m of 0 GA cable to run all that power and then after that you would only get a couple of nitrous like bursts of power (only a few psi of positive pressure generated) for a few seconds each before the batteries were drained.
so yeah...
and "electrical superchargers" are a huge waste of money, if you take it out you may find performance increases
a little electric fan running +12v and a handful of amps will never provide positive pressure
if you wanted a true electric supercharger you would need a motor about the size of a electric leaf blower that runs at 240v and then 10x 24v batteries wired in series in the boot plus around 15m of 0 GA cable to run all that power and then after that you would only get a couple of nitrous like bursts of power (only a few psi of positive pressure generated) for a few seconds each before the batteries were drained.
so yeah...
~2.0L Lanos~EHPAS~H&R Springs~KYB/GTS Shocks~
Re: What is wrong with my 1.5L engine?
Hi Ahmed
you have invested in alot of parts that will not add to your performance...
increasing performance in terms of acceleration time and top speed comes down to power to weight ratio... so you either add power or lose weight, losing weight is far less expensive but a rather limited area specially if we are talking about a daily used car
increasing power will come down to burning more air/fuel mixture... no matter what you hear or read anywhere else... this is the real source of power
fuel is never the issue so it will come down to air... you either shove more air into your current engine thus increasing your volumetric efficiency or increase the engine's displacement.
the first approach is translated into using a turbo or a super charger (forced induction) and i mean the real stuff not the BS sold on ebay like electric super chargers and all that stuff, using NOS is a source of adding more air or to be exact "more oxygen" to the intake charge but it has so much drawbacks when it comes to use compared to a turbo or a super charger. also swapping a 16 valve DOHC head will increase your volumetric effervescence on high RPMs thus you will gain more HP but your max torque will shift from 3400RPM to some 4000RPM or so
the second approach involves many options such as boring or stroking or even an engine swap, i guess stroking the 1.5 is not attainable but you can bore it to be 1600cc or even swap it for a 1600 DOHC... that will give you some 23HP more
their is one more option that i don't know where to categorize it... high compression pistons, i have found out that the 2005 opel corsa has a very similar engine to ours and its compression ratio is 10.5:1 and it outputs 101HP... but you got to note that this is a 1600 engine so this option is not attainable unless you are going to bore your block
those are the options available for you an WILL give you more power, all other gadgets and add ons are just a waist as you have experienced.
MMamdouh
you have invested in alot of parts that will not add to your performance...
increasing performance in terms of acceleration time and top speed comes down to power to weight ratio... so you either add power or lose weight, losing weight is far less expensive but a rather limited area specially if we are talking about a daily used car
increasing power will come down to burning more air/fuel mixture... no matter what you hear or read anywhere else... this is the real source of power
fuel is never the issue so it will come down to air... you either shove more air into your current engine thus increasing your volumetric efficiency or increase the engine's displacement.
the first approach is translated into using a turbo or a super charger (forced induction) and i mean the real stuff not the BS sold on ebay like electric super chargers and all that stuff, using NOS is a source of adding more air or to be exact "more oxygen" to the intake charge but it has so much drawbacks when it comes to use compared to a turbo or a super charger. also swapping a 16 valve DOHC head will increase your volumetric effervescence on high RPMs thus you will gain more HP but your max torque will shift from 3400RPM to some 4000RPM or so
the second approach involves many options such as boring or stroking or even an engine swap, i guess stroking the 1.5 is not attainable but you can bore it to be 1600cc or even swap it for a 1600 DOHC... that will give you some 23HP more
their is one more option that i don't know where to categorize it... high compression pistons, i have found out that the 2005 opel corsa has a very similar engine to ours and its compression ratio is 10.5:1 and it outputs 101HP... but you got to note that this is a 1600 engine so this option is not attainable unless you are going to bore your block
those are the options available for you an WILL give you more power, all other gadgets and add ons are just a waist as you have experienced.
MMamdouh
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RichieOzzie
- Junior
- Posts: 126
- Joined: Sun Feb 05, 2006 1:49 pm
- Location: New South Wales, Australia.
Re: What is wrong with my 1.5L engine?
Could always use the sneaky little NOS kit like me!!. This gives a few upsets at the lights, but the little NOS containers do not last too long, so best kept for that "Special occasion"
They are a dry type kit with just a small bore feed to the inlet manifold, and trigger fired. Never done the engine any harm up to present as they are built pretty strong, and the NOS kit is not Drag-car weaponry.
Most engines can take a shot or so to be honest, unless they are tuned already, in which case it can be very complicated to set-up.
I have done a few of the mods in here, and they work well. Remember it will never be a GTR, but can, if modded a little, be a different car, and will shock a few people.!!
To drive a supercharger in the engine would need around 7 BHP to get any kind of effective boost and volume. Imagine the battery needed to drive this, plus the size of the inducer!!
One of my Supercharged engines here runs 23 psi through a 3 cylinder engine, 1.5 liter. Produces over 400bhp at the moment.
Turbo charging is a good idea. There are a few project cars in the forum, and to be honest, you could get away with any really complex setup if you kept boost to around 6psi.... but you would feel it for sure. I have been looking at using one of the old Seadoo chargers I have, but the issue is driving it in the engine bay, and keeping it lubricated.... we will see how I go.
Supercharging uses energy from the engine to drive it, but turbo-charging uses effectively wasted energy from the exhaust gas being pushed out the back, so takes less power to generate boost. Supercharging is good for low engine RPM boost, where turbo tends to get "Peaky", and needs the engine revving up to get it spooling up to give boost.
You are probably best to start with things like changing the octane plug around, fitting a real FPR, a good O2 sensor, and opening up the exhaust pipe a little to about 2 3/4" diameter. Use a low viscosity oil, good clean air filter, V groove plugs and good ignition leads. Make sure the brakes are not binding, get the tyre pressures correct.
Rule number one when it comes to tuning......................
Make sure the engine is absolutely standard, and working correctly first, by checking all sensors, electrically, compression, air leaks, and inlet area for carbon build-up blocking the inlet air. Maybe pulll off the resonator in the inlet area too.
Put the car on a flat, level surface. Handbrake off, and try to push it. If it is smooth, and continues easily, the rolling resistance is low, and will help. If it is hard to push, and stops quickly, then something is holding it back.... this takes power to overcome... = wasted horse-power.
The trick is to Add-up all the small mods, which will be all counted when you hit the gas. Every small mod counts!!
Rev the engine too hard, and it passes its peak, and slows off. Rev it to where it produces best power quickly and effectively, then change gear. Do not hang on to the gear until it starts to mis-fire at the limiter. at this point, you have gone way past its power-band, and wasted acceleration time. Torque is what pulls the wheels around, and for sure, at the limiter, it is past and gone backwards!
Another thing I have heard, is that the camshaft lobes wear on the far end of the cam, which reduce power. A good oil is important.
Many cars out there are badly tuned/running, and waste fuel. Use it efficiently, and you would be suprised.
I think that helps.... I know I know what I am saying, but .....
They are a dry type kit with just a small bore feed to the inlet manifold, and trigger fired. Never done the engine any harm up to present as they are built pretty strong, and the NOS kit is not Drag-car weaponry.
Most engines can take a shot or so to be honest, unless they are tuned already, in which case it can be very complicated to set-up.
I have done a few of the mods in here, and they work well. Remember it will never be a GTR, but can, if modded a little, be a different car, and will shock a few people.!!
To drive a supercharger in the engine would need around 7 BHP to get any kind of effective boost and volume. Imagine the battery needed to drive this, plus the size of the inducer!!
One of my Supercharged engines here runs 23 psi through a 3 cylinder engine, 1.5 liter. Produces over 400bhp at the moment.
Turbo charging is a good idea. There are a few project cars in the forum, and to be honest, you could get away with any really complex setup if you kept boost to around 6psi.... but you would feel it for sure. I have been looking at using one of the old Seadoo chargers I have, but the issue is driving it in the engine bay, and keeping it lubricated.... we will see how I go.
Supercharging uses energy from the engine to drive it, but turbo-charging uses effectively wasted energy from the exhaust gas being pushed out the back, so takes less power to generate boost. Supercharging is good for low engine RPM boost, where turbo tends to get "Peaky", and needs the engine revving up to get it spooling up to give boost.
You are probably best to start with things like changing the octane plug around, fitting a real FPR, a good O2 sensor, and opening up the exhaust pipe a little to about 2 3/4" diameter. Use a low viscosity oil, good clean air filter, V groove plugs and good ignition leads. Make sure the brakes are not binding, get the tyre pressures correct.
Rule number one when it comes to tuning......................
Make sure the engine is absolutely standard, and working correctly first, by checking all sensors, electrically, compression, air leaks, and inlet area for carbon build-up blocking the inlet air. Maybe pulll off the resonator in the inlet area too.
Put the car on a flat, level surface. Handbrake off, and try to push it. If it is smooth, and continues easily, the rolling resistance is low, and will help. If it is hard to push, and stops quickly, then something is holding it back.... this takes power to overcome... = wasted horse-power.
The trick is to Add-up all the small mods, which will be all counted when you hit the gas. Every small mod counts!!
Rev the engine too hard, and it passes its peak, and slows off. Rev it to where it produces best power quickly and effectively, then change gear. Do not hang on to the gear until it starts to mis-fire at the limiter. at this point, you have gone way past its power-band, and wasted acceleration time. Torque is what pulls the wheels around, and for sure, at the limiter, it is past and gone backwards!
Another thing I have heard, is that the camshaft lobes wear on the far end of the cam, which reduce power. A good oil is important.
Many cars out there are badly tuned/running, and waste fuel. Use it efficiently, and you would be suprised.
I think that helps.... I know I know what I am saying, but .....
Re: What is wrong with my 1.5L engine?
thanks guys for support . My engine is healthy . even it generates water at the muffler tip . I chicked it many times on the obd2 scan tool . and everything is fine
the problem is that I compare that engine with the one which was on my previous 1999 lanos 1.5l . that engine was nearly the same . with diffrent ECU and injectors I think . but that engine was torquey . I have a big diffrence between this and that . I want at the begining to reach the same power from my aveo engine . I don't know why GM did that . to produce a lower power engine . very strange thing .
my friend have a mazda . and every small add-on the engine it makes a diffrence . me not . I read alot about the BIG spark Plugs Wires , and alot also about the New revolution in spark plugs as PULSTAR spark plugs . even vedios on youtube . but nothing happened to me .
My question is . what is the part in my engine which limit any modifications on it? I feel that there is a part did so . Like a manifold or sensor or something like that .
the problem is that I compare that engine with the one which was on my previous 1999 lanos 1.5l . that engine was nearly the same . with diffrent ECU and injectors I think . but that engine was torquey . I have a big diffrence between this and that . I want at the begining to reach the same power from my aveo engine . I don't know why GM did that . to produce a lower power engine . very strange thing .
my friend have a mazda . and every small add-on the engine it makes a diffrence . me not . I read alot about the BIG spark Plugs Wires , and alot also about the New revolution in spark plugs as PULSTAR spark plugs . even vedios on youtube . but nothing happened to me .
My question is . what is the part in my engine which limit any modifications on it? I feel that there is a part did so . Like a manifold or sensor or something like that .
Re: What is wrong with my 1.5L engine?
power reducing mods:
big wheels
sound system
electric supercharger
power neutral mods:
spark wires
spark plugs
oil
power increasing mods:
exhaust
intake
fuel
air
and tuning to get it to work in harmony
in my opinion 2 3/8" exhaust on a stock 1.5 is way too big! (that's the whole "an engine needs backpressure" BS)
however, a big exhaust with the engine tuned to match it would work
one thing you should know... the only aspect of performance that comes cheap is weight reduction...
take out the big speakers, put the stock wheels on... you will feel a difference
big wheels
sound system
electric supercharger
power neutral mods:
spark wires
spark plugs
oil
power increasing mods:
exhaust
intake
fuel
air
and tuning to get it to work in harmony
in my opinion 2 3/8" exhaust on a stock 1.5 is way too big! (that's the whole "an engine needs backpressure" BS)
however, a big exhaust with the engine tuned to match it would work
one thing you should know... the only aspect of performance that comes cheap is weight reduction...
take out the big speakers, put the stock wheels on... you will feel a difference
~2.0L Lanos~EHPAS~H&R Springs~KYB/GTS Shocks~
Re: What is wrong with my 1.5L engine?
Best thing for feel is blue-print the head and mani's. Bin the oem manifold, its a terrible bit of work. Match the mani's to the ports.
Actually, plugs can help in power "production" by the way. Good, clean spread of 'clean' ignition across the rev range is an advantage in forward momentum. Pulls the gears better = acceleration is better. No power increase, but better delivery.
Wheels.... Hmmm, now theres a subject. Its the actual rolling diameter that is important. Alter this, and alter the gearing effectively. Measure the rolling diameter, if its the same, all will be good, if its greater, then trouble is ahead!
Best thing is the few mods on the forum that do work firstly. If it runs well, the apply them, and then take a look at "what next".
My last write-up when completed is a good idea on the 8v engine. They do run weak.... period!!
Force a bit more fuel through it with better control. FIT A GOOD Fuel Pressure Regulator. Bin the crap OEM one, it never left the factory in spec for sure.
Get the injectors cleaned inside and out, and then flow tested. ....Or better still, get better quality ones. OEM ones are cheap and nasty!!
Change the CTS coolant temp sensor. It fits just under the Coil pack. 19mm spanner and out it comes. Dont get coolant in the connector when you do remove/replace it. ... they are cheap at $17 a shot, and they do slowly deteriorate.
Check setting of the Throttle body..... oh, and make sure it is actually opening all the way. Many have missed this. !!!
....Seriously, I changed the FPR, and it made it a new car. More 'torquey', cleaner pulling from low RPM, and freeway roll-on acceleration was heaps better.
Change the octane plug over to the Black connected to the brown/white wire. Feed it Real fuel, no ethanol... this will help economy for sure, and it burns better.
Oh, and aone we should all keep in line is the wheels... tracking, get it checked.
I have had 3 1.5 SOHC Lanos's, and they were never identical to be honest. One had the fuel line flattened just where it curves around the floor to the firewall. This took ages to figure out as a problem. Fuel pressure was high enough, but flow was down.... this made it hesitate when I "Hoofed" it. Fuelling is important, especially on these cars. Maybe?
One the other, the ECU ROM chip was badly seated, and this gave me all sorts of wierd problems. Re-seat it.
Fuel pressure & flow can be affected by the current the pump gets... check connectors are all clean. Change the Fuel filter. There is no set time for them to get blocked with crap. Happened to me 2 weeks after changing one at service time!!. Damn thing was almost solidly blocked when I looked!!. Musta got me some cheap, bottom of the tank petrol somewhere.
Actually, plugs can help in power "production" by the way. Good, clean spread of 'clean' ignition across the rev range is an advantage in forward momentum. Pulls the gears better = acceleration is better. No power increase, but better delivery.
Wheels.... Hmmm, now theres a subject. Its the actual rolling diameter that is important. Alter this, and alter the gearing effectively. Measure the rolling diameter, if its the same, all will be good, if its greater, then trouble is ahead!
Best thing is the few mods on the forum that do work firstly. If it runs well, the apply them, and then take a look at "what next".
My last write-up when completed is a good idea on the 8v engine. They do run weak.... period!!
Force a bit more fuel through it with better control. FIT A GOOD Fuel Pressure Regulator. Bin the crap OEM one, it never left the factory in spec for sure.
Get the injectors cleaned inside and out, and then flow tested. ....Or better still, get better quality ones. OEM ones are cheap and nasty!!
Change the CTS coolant temp sensor. It fits just under the Coil pack. 19mm spanner and out it comes. Dont get coolant in the connector when you do remove/replace it. ... they are cheap at $17 a shot, and they do slowly deteriorate.
Check setting of the Throttle body..... oh, and make sure it is actually opening all the way. Many have missed this. !!!
....Seriously, I changed the FPR, and it made it a new car. More 'torquey', cleaner pulling from low RPM, and freeway roll-on acceleration was heaps better.
Change the octane plug over to the Black connected to the brown/white wire. Feed it Real fuel, no ethanol... this will help economy for sure, and it burns better.
Oh, and aone we should all keep in line is the wheels... tracking, get it checked.
I have had 3 1.5 SOHC Lanos's, and they were never identical to be honest. One had the fuel line flattened just where it curves around the floor to the firewall. This took ages to figure out as a problem. Fuel pressure was high enough, but flow was down.... this made it hesitate when I "Hoofed" it. Fuelling is important, especially on these cars. Maybe?
One the other, the ECU ROM chip was badly seated, and this gave me all sorts of wierd problems. Re-seat it.
Fuel pressure & flow can be affected by the current the pump gets... check connectors are all clean. Change the Fuel filter. There is no set time for them to get blocked with crap. Happened to me 2 weeks after changing one at service time!!. Damn thing was almost solidly blocked when I looked!!. Musta got me some cheap, bottom of the tank petrol somewhere.
Re: What is wrong with my 1.5L engine?
yeah, what I was taught was the comparison of swinging a bowling ball in circles compared to the effort needed to swing a bowling ball on a longer bit of string aroundRichieb wrote: Wheels.... Hmmm, now theres a subject. Its the actual rolling diameter that is important. Alter this, and alter the gearing effectively. Measure the rolling diameter, if its the same, all will be good, if its greater, then trouble is ahead!
i.e. the further the weight is from the centre/pivot point the harder it will be to turn
~2.0L Lanos~EHPAS~H&R Springs~KYB/GTS Shocks~
Re: What is wrong with my 1.5L engine?
Kinda right there, effort at greater distance from centre... You're on ya own with the bowlin' ball, am not catchin it!!!
If I remember right, and I can explain it.
Bear in mind that tyre circumfrence(like any circle) is 3.142(or Pi to more accurate if you care to) x Diameter. Diameter is 2x radius. RADIUS is the part we are interested in..!!
14" rim will be 356mm, or 35.56cm Diameter.
Tyres are sold as Rim Diameter in inches/tread aspect ratio as %/Tread width in Milimeters ...for some obscure reason!!
Say...
14" rim with 50% profile tyre at 200/50vr14 <-made up tyre!!
50% of the tread width of 200mm = 10cm. !!! Yep metric and imperial!!... for some reason.
So add 10cm to both sides of the 14"= 35.56 +20(10cm x2), add all up and the rolling circumfrence would be greater than say for instance 200/35 vr13. The aspect ratio of tread width to Rim edge to tyre tread is what its about. adding 35% of 200 =7cm to each edge of the diameter of the rim.
So First examples Diameter would be 55.56cm, second one would be 49.56cm. so circumfrence of wheel 1 is +/-174.5, tyre 2 is 155.7 (when using 3.142 as Pi) ----- puts your speedo out. It thinks it travels less distance on the bigger tyre!!(Cops love this), but you actually are travelling faster at say 60kmh!!
Err, this is getting difficult to explain here?!?!
But even with a setup change of aspect ratio in the examples above, the difference is one travels nearly 20cm further!!(for the made up tyre) everytime it revolves. Now the gearbox with this will be what is supposed to be 1st gear, but has to exert the power to pull second gear at the ratios it has. All good if you can get it up a steep standing start?!?, but then as you try to get to 5th gear, which in effect will be a 6th gear ratio, and even higher a gear!!.... the engine just doesn't have the torque to pull this, and will bog down, taking 15km to get to top speed, which when it can, on the flat, will be quicker..... albeit 5 mins to get there!!.
All the rolling circumfrence increase does is alter the ratio of the crankshaft rotation to the wheel circumfrence rotational distance the car travels. To move the car takes energy... from the engine. It is now trying to move the car further with the same energy the engine produces.... often it gets more difficult!!, and slower to do.
NOW!!!, The only trouble is....
....The gearbox is matched to the torque output of the engine at peak output. Change this, and it simply will not pull the gear as per usual driving. The RPM is lower, therefore the torque produced at the crank is less, so it will slow down acceleration.
NOW, put a lower aspect ratio on the 13" rim, say from 70 to 50, then the rolling circumfrence has decreased, and it will allow the engine to get to peak torque/power quicker and earlier. kinda like 1/2, 1st, 1 1/2st, 2nd... etc, and top gear could become 4 1/2th !!, it will accelerate quicker in top gear, where say before it may pull pretty well, the increase will show itself on inclines.
Thats why your car seems to accelerate quicker on worn tyres.... the rolling circumfrence is less, and therefore power to turn it once is produced earlier/easier.
Torque is measured in units of Kg/m(Actually Nm Newton Meters where 1 newton of mass at 1 metre, but easier to work through in this form. Any turning force around a center is defined as torque in fact, but I will use Kg/M here), or Kilograms per meter.
1 Kg on a stick 1 meter(1Kg/m) long isnt easy to hold by hand, but increase it to 2 Kg(2kg/m)..!!. when the point where you hold it is the centre if it rotated around your hand, which is where the torque would be measured. Its the amount of turning/twisting pressure/strain/stress it exerts on this point is Torque(at your hand/wrist). The Torque/twisting force in this example will be 2Kg/m.
So, put this on an engine, and say it produces 100Kg/m of torque at 6000rpm, at 1/2 metre it will be 200Kg/m and 1/4 metre it will be 400Kg/m which is the force it can exert..... Same as the stick with 1Kg at 1/2 meter... its easier, and less effort is needed. So you could maybe lift 2Kg at 1/2meter with your hand now.!!
Now multiply the torque by use of gears by 2.5 times(one cog 2.5 times larger or more teeth than the other in the gear box), and the 400Kg/M becomes 1000Kg/m..... it will now be able to twist the driveshaft around with a tyre of 0.25m radius on the end... and the car moves forward from rest. Effectively, the car once rolling can accelerate with constant torque applied to the driveshaft, and the horsepower will enable it to keep up the pressure to do it. Once rolling, alter the gears when it has reached 6000rpm to 500rpm below, and off it pulls, up to the peak torque rpm.... and so on. This is the best place to change gear... where the Torque and BHP curves cross on a chart.
The gears are setup to accelerate the car which weighs in at say 1000kg, and the radius of the wheel is say 250mm(1/4) metre. The force it produces to turn the wheel will be 4000kg at "0.25" metre to move the car on the flat, which is the same as 1000kg/M.(1000kg at 1 meter is the same as 2000kg at 1/2 metre), the wheel needs 4000Kg at 1/4(0.25 metre) we alter the force by use of gears. So, now we say the crank turns 2.5 times to once at the driveshaft end, and the energy stored in the flywheel will be x2.5 greater, and therfore multiply the twisting/turning force(torque).
RADIUS of the tyre plus Rim is very important, as THIS is the distance at which the engine is trying to twist/turn the driveshaft from(like the weight on a stick), but being held back by the weight of the car at start, and as it tries to accelerate from rest.
Larger radius, the more power or torque it needs to apply to get the weight of the car moving, so we rev it up to get more power or energy into the flywheel, and slip the clutch... It moves!
Basically, a badly matched wheel and tyre really messes up the vehicle design. Smaller rotating wheel will give faster acceleration, but top-end will be less if you get there in the sprint. I would prefer the 13" with a 65 or less ratio tyre. It will accelerate faster, and pull 5th easier, but the designers wanted Km per liter to be good, not the 0-100 times. Its what sells the car. Increase torque with forced induction, and it will pull the larger rim and tyre!!
I think this all makes sense, but at least I understand it!?!?!? D'oh!
If I remember right, and I can explain it.
Bear in mind that tyre circumfrence(like any circle) is 3.142(or Pi to more accurate if you care to) x Diameter. Diameter is 2x radius. RADIUS is the part we are interested in..!!
14" rim will be 356mm, or 35.56cm Diameter.
Tyres are sold as Rim Diameter in inches/tread aspect ratio as %/Tread width in Milimeters ...for some obscure reason!!
Say...
14" rim with 50% profile tyre at 200/50vr14 <-made up tyre!!
50% of the tread width of 200mm = 10cm. !!! Yep metric and imperial!!... for some reason.
So add 10cm to both sides of the 14"= 35.56 +20(10cm x2), add all up and the rolling circumfrence would be greater than say for instance 200/35 vr13. The aspect ratio of tread width to Rim edge to tyre tread is what its about. adding 35% of 200 =7cm to each edge of the diameter of the rim.
So First examples Diameter would be 55.56cm, second one would be 49.56cm. so circumfrence of wheel 1 is +/-174.5, tyre 2 is 155.7 (when using 3.142 as Pi) ----- puts your speedo out. It thinks it travels less distance on the bigger tyre!!(Cops love this), but you actually are travelling faster at say 60kmh!!
Err, this is getting difficult to explain here?!?!
But even with a setup change of aspect ratio in the examples above, the difference is one travels nearly 20cm further!!(for the made up tyre) everytime it revolves. Now the gearbox with this will be what is supposed to be 1st gear, but has to exert the power to pull second gear at the ratios it has. All good if you can get it up a steep standing start?!?, but then as you try to get to 5th gear, which in effect will be a 6th gear ratio, and even higher a gear!!.... the engine just doesn't have the torque to pull this, and will bog down, taking 15km to get to top speed, which when it can, on the flat, will be quicker..... albeit 5 mins to get there!!.
All the rolling circumfrence increase does is alter the ratio of the crankshaft rotation to the wheel circumfrence rotational distance the car travels. To move the car takes energy... from the engine. It is now trying to move the car further with the same energy the engine produces.... often it gets more difficult!!, and slower to do.
NOW!!!, The only trouble is....
....The gearbox is matched to the torque output of the engine at peak output. Change this, and it simply will not pull the gear as per usual driving. The RPM is lower, therefore the torque produced at the crank is less, so it will slow down acceleration.
NOW, put a lower aspect ratio on the 13" rim, say from 70 to 50, then the rolling circumfrence has decreased, and it will allow the engine to get to peak torque/power quicker and earlier. kinda like 1/2, 1st, 1 1/2st, 2nd... etc, and top gear could become 4 1/2th !!, it will accelerate quicker in top gear, where say before it may pull pretty well, the increase will show itself on inclines.
Thats why your car seems to accelerate quicker on worn tyres.... the rolling circumfrence is less, and therefore power to turn it once is produced earlier/easier.
Torque is measured in units of Kg/m(Actually Nm Newton Meters where 1 newton of mass at 1 metre, but easier to work through in this form. Any turning force around a center is defined as torque in fact, but I will use Kg/M here), or Kilograms per meter.
1 Kg on a stick 1 meter(1Kg/m) long isnt easy to hold by hand, but increase it to 2 Kg(2kg/m)..!!. when the point where you hold it is the centre if it rotated around your hand, which is where the torque would be measured. Its the amount of turning/twisting pressure/strain/stress it exerts on this point is Torque(at your hand/wrist). The Torque/twisting force in this example will be 2Kg/m.
So, put this on an engine, and say it produces 100Kg/m of torque at 6000rpm, at 1/2 metre it will be 200Kg/m and 1/4 metre it will be 400Kg/m which is the force it can exert..... Same as the stick with 1Kg at 1/2 meter... its easier, and less effort is needed. So you could maybe lift 2Kg at 1/2meter with your hand now.!!
Now multiply the torque by use of gears by 2.5 times(one cog 2.5 times larger or more teeth than the other in the gear box), and the 400Kg/M becomes 1000Kg/m..... it will now be able to twist the driveshaft around with a tyre of 0.25m radius on the end... and the car moves forward from rest. Effectively, the car once rolling can accelerate with constant torque applied to the driveshaft, and the horsepower will enable it to keep up the pressure to do it. Once rolling, alter the gears when it has reached 6000rpm to 500rpm below, and off it pulls, up to the peak torque rpm.... and so on. This is the best place to change gear... where the Torque and BHP curves cross on a chart.
The gears are setup to accelerate the car which weighs in at say 1000kg, and the radius of the wheel is say 250mm(1/4) metre. The force it produces to turn the wheel will be 4000kg at "0.25" metre to move the car on the flat, which is the same as 1000kg/M.(1000kg at 1 meter is the same as 2000kg at 1/2 metre), the wheel needs 4000Kg at 1/4(0.25 metre) we alter the force by use of gears. So, now we say the crank turns 2.5 times to once at the driveshaft end, and the energy stored in the flywheel will be x2.5 greater, and therfore multiply the twisting/turning force(torque).
RADIUS of the tyre plus Rim is very important, as THIS is the distance at which the engine is trying to twist/turn the driveshaft from(like the weight on a stick), but being held back by the weight of the car at start, and as it tries to accelerate from rest.
Larger radius, the more power or torque it needs to apply to get the weight of the car moving, so we rev it up to get more power or energy into the flywheel, and slip the clutch... It moves!
Basically, a badly matched wheel and tyre really messes up the vehicle design. Smaller rotating wheel will give faster acceleration, but top-end will be less if you get there in the sprint. I would prefer the 13" with a 65 or less ratio tyre. It will accelerate faster, and pull 5th easier, but the designers wanted Km per liter to be good, not the 0-100 times. Its what sells the car. Increase torque with forced induction, and it will pull the larger rim and tyre!!
I think this all makes sense, but at least I understand it!?!?!? D'oh!
Re: What is wrong with my 1.5L engine?
Jeez, that took some cobbling together!
Here's a link with a good way to see if you have the right tyres and rims that don't alter the cars performance.
http://www.club80-90syncro.co.uk/Syncro ... ulator.htm
Here's a link with a good way to see if you have the right tyres and rims that don't alter the cars performance.
http://www.club80-90syncro.co.uk/Syncro ... ulator.htm
Re: What is wrong with my 1.5L engine?
"1 Kg on a stick 1 meter(1Kg/m) long isnt easy to hold by hand, but increase it to 2 Kg(2kg/m)..!!. when the point where you hold it is the centre if it rotated around your hand, which is where the torque would be measured. Its the amount of turning/twisting pressure/strain/stress it exerts on this point is Torque(at your hand/wrist). The Torque/twisting force in this example will be 2Kg/m."
That's kind of what I was getting at...
That's kind of what I was getting at...
~2.0L Lanos~EHPAS~H&R Springs~KYB/GTS Shocks~