jamesmartin
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are you sure have you proof ,ive never seen a tdi do this
bit more omph from 300tdi help please
- Thread starter 1968unclefester
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Tuskenraider
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and how many tdis have you seen with no actuator pipe on
AFAIK the 300tdi runs around 15psi which is the limit on the turbo it uses. Overboosting it will shorten its life rapidly.
jamesmartin
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most i see are wound right up, and have been for years ,admittedly ive never seen any one try to rev it to destruction while stood,but under normal driving,are you talking from experienc or google
davek0974
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I was told once that on petrol engines, a lean burn is hotter and on diesel engines a rich burn is hotter.
Diesels are controlled by the amount of fuel injected only, more fuel = more heat = more power or black smoke if not enough air
Diesels are controlled by the amount of fuel injected only, more fuel = more heat = more power or black smoke if not enough air
IanFiTheDwarf
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Yes petrol engines will run hotter when lean and diesels run hotter when richer.
In a diesel engine it is all about the fuel, the more you have the more power you will get even to the point when you get loads of smoke you will still get more power but just less efficiently and you will get much higher exhaust gas temperatures which could lead to melting down the internals of your engine.
As you increase the fuelling you need to increase the air to avoid smoke and keep the exhaust gas temperatures down. It is also best to have colder more dense air as this will again be more efficient and help to keep the exhaust gas temperatures down. As said before the best thing to do is fit a better intercooler and better flowing pipe work but you can also get away with a little bit more boost on almost any diesel.
You can increase the boost in several ways,
Adjusting the waste gate actuator or shortening it will work but is easy to get wrong and end up with it sticking
A bleed valve will work but your boost can change when other engine conditions change like under bonnet temperature and the condition of your air filter
A gated boost valve (ball and spring type) or an electronic boost controller will work best as it will give tighter control of the changeover from closed to open waste gate keeping it fully closed longer then opening it more quickly which improves mid range boost.
As said before the 300tdi is pretty close to the maximum boost already but in my opinion there is always room for a little increase if you are sensible about it so two or three psi shouldnt hurt but might keep the smoke away and the egt down a bit with your foot down up a steep hill.
If you are going to play with boost in any way you should always use a boost gauge at a minimum just for testing but better fitting one permanently to keep an eye on your boost.
Disconnecting the pipe from the actuator is shear lunacy on any car but especially on a petrol! You would have to be very lucky not to destroy your engine completely.
There are some older diesel engines which do not have waste gates but these are normaly stationery engines or big low revving engines on plant or locomotives. These engines get away with it because they dont have to operate across a wide rev range and have a turbo with a very roomy housing so the exhaust gassed can slip past the turbine limiting the boost to an extent.
In a diesel engine it is all about the fuel, the more you have the more power you will get even to the point when you get loads of smoke you will still get more power but just less efficiently and you will get much higher exhaust gas temperatures which could lead to melting down the internals of your engine.
As you increase the fuelling you need to increase the air to avoid smoke and keep the exhaust gas temperatures down. It is also best to have colder more dense air as this will again be more efficient and help to keep the exhaust gas temperatures down. As said before the best thing to do is fit a better intercooler and better flowing pipe work but you can also get away with a little bit more boost on almost any diesel.
You can increase the boost in several ways,
Adjusting the waste gate actuator or shortening it will work but is easy to get wrong and end up with it sticking
A bleed valve will work but your boost can change when other engine conditions change like under bonnet temperature and the condition of your air filter
A gated boost valve (ball and spring type) or an electronic boost controller will work best as it will give tighter control of the changeover from closed to open waste gate keeping it fully closed longer then opening it more quickly which improves mid range boost.
As said before the 300tdi is pretty close to the maximum boost already but in my opinion there is always room for a little increase if you are sensible about it so two or three psi shouldnt hurt but might keep the smoke away and the egt down a bit with your foot down up a steep hill.
If you are going to play with boost in any way you should always use a boost gauge at a minimum just for testing but better fitting one permanently to keep an eye on your boost.
Disconnecting the pipe from the actuator is shear lunacy on any car but especially on a petrol! You would have to be very lucky not to destroy your engine completely.
There are some older diesel engines which do not have waste gates but these are normaly stationery engines or big low revving engines on plant or locomotives. These engines get away with it because they dont have to operate across a wide rev range and have a turbo with a very roomy housing so the exhaust gassed can slip past the turbine limiting the boost to an extent.
Suris
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Nice write up there IanFiTheDwarf
Dufty
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Talk of enriching the fuel mix, thereby increasing the heat and theneed for more air, is swiftly followed by discussion around fitting larger pipes and intervooler. This is all very well nobody has discussed the potentially critical effect of all that extra cold air on the now much hotter block. Cold shock can cause catastrophic failure of an engine.
Fur Trapper
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A larger intercooler increases the amount of air that is available to the motor by way of the turbo. And you will not as you say cold shock the motor.
In your opinion what is the air temp going into the motor?
Dufty
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It increases the air available not only by de-restricting the air flow by also by increasing the air density through it's cooling effects (in much the same way as nitrous but on a significantly lower scale).
We may only be talking a matter of degrees but combine this with the net effect of increasing the fuel mix (thereby increasing the combustion temperature) and the risk of the colder air via the turbo meeting a now proportionately higher temperature of the cylinder and we start to move outside of normal tolerances, reducing the life expectancy of the block.
Diesels in particular are more susceptible to this type of damage given their inherently higher operating temperatures.
Extra power is rarely (if ever) 'free', you just have to weigh up the costs.
We may only be talking a matter of degrees but combine this with the net effect of increasing the fuel mix (thereby increasing the combustion temperature) and the risk of the colder air via the turbo meeting a now proportionately higher temperature of the cylinder and we start to move outside of normal tolerances, reducing the life expectancy of the block.
Diesels in particular are more susceptible to this type of damage given their inherently higher operating temperatures.
Extra power is rarely (if ever) 'free', you just have to weigh up the costs.
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IanFiTheDwarf
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I have never heard of cold shock being caused by the air being drawn in, the air from the turbo can be over 150 deg C and even an infinitely large intercooler can not cool the oar below the ambient air temperature so its probably good going to get the temp down near 50 or 60 deg C.
Air has a very low heat capacity compared to water so the cooling affect you would get from the air on a cold rainy winters day will be many times more than you could get from even the best intercooler.
Air has a very low heat capacity compared to water so the cooling affect you would get from the air on a cold rainy winters day will be many times more than you could get from even the best intercooler.
Fur Trapper
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Fur Trapper
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Combustion temp is a max of 1850F that is all the hotter diesel will burn period. No matter how much fuel you put into a cylinder, and with out air it wont burn. If you increase fuel you also need to increase air also and only way to get air volume is a larger inner cooler.
sible88
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Looks like I was right then??
A larger intercooler does make a difference.
A larger intercooler does make a difference.
Suris
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I tend to agree with you. Lets wait for jamesmartin to sort this out
Even the lord god of all things Land Rover aint gonna sort that out.
