dave t Posted August 2, 2012 Share Posted August 2, 2012 Is anyone running a vnt turbo on a 300 tdi? and if so what boost are you running? thanks Dave Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted August 2, 2012 Share Posted August 2, 2012 I am about to have one fitted .... I will run the same max boost as before 1.05 bar = 15psi. I have driven the prototype Defender with 300tdi engine and the big difference is the torque at low revs. Put your foot down at 60kph in 5th and it goes But the top end will be about the same. I think it is a Puma turbo ..... Quote Link to comment Share on other sites More sharing options...
dave t Posted August 2, 2012 Author Share Posted August 2, 2012 the turbo I have fitted is from Allard which is a garret turbo from a merc sprinter I believe. I have been playing with the boost and at stock boost there doesnt seem to be much increase in power but its spread over the whole rev range and there is no lag if you up the fueling. I have run (for short bursts only ) 30psi and fueling to match and it absolute flies but that is too much boost for longevity, the turbo will handle it but probably not the engine. I am now running about 24pisi at WOT at 3500rpm which is ok as long as it doesnt sit there all day. At stock the boost limitations are more about the stock turbo, the motor can take a bit more, only time will tell if I am right or not! the reason for my post, I would like to swap experiences with others who have a vnt fitted cheers Dave Quote Link to comment Share on other sites More sharing options...
Landy-Novice Posted August 2, 2012 Share Posted August 2, 2012 ... the turbo I have fitted is from Allard which is a garret turbo from a merc sprinter I believe. ... can you expand on this? as i want but but i cant afford £1300! what make/model sprinter is it off? :) Quote Link to comment Share on other sites More sharing options...
dave t Posted August 3, 2012 Author Share Posted August 3, 2012 can you expand on this? as i want but but i cant afford £1300! what make/model sprinter is it off? :) I am sorry I dont know its just something someone told me. I will see if I can find the number on the unit. I just know its a fantastic unit it just transforms the performance of the 300 tdi Quote Link to comment Share on other sites More sharing options...
discomikey Posted August 3, 2012 Share Posted August 3, 2012 the turbo I have fitted is from Allard which is a garret turbo from a merc sprinter I believe. I have been playing with the boost and at stock boost there doesnt seem to be much increase in power but its spread over the whole rev range and there is no lag if you up the fueling. I have run (for short bursts only ) 30psi and fueling to match and it absolute flies but that is too much boost for longevity, the turbo will handle it but probably not the engine. I am now running about 24pisi at WOT at 3500rpm which is ok as long as it doesnt sit there all day. At stock the boost limitations are more about the stock turbo, the motor can take a bit more, only time will tell if I am right or not! the reason for my post, I would like to swap experiences with others who have a vnt fitted cheers Dave these pressures in a 300TDI the absolute max is 18psi at the engine, the head bolts just cant take it and stretch.. a credit to your engine (p.s. im running 20 with a standard turbo on a 200) Quote Link to comment Share on other sites More sharing options...
dave t Posted August 3, 2012 Author Share Posted August 3, 2012 I think its more the standard turbo rather than the engine itself that wont take the boost its too small and will become inefficient causing lots of heat. The big vnt will handle the high boost easily and as long as its not overfueled it shouldnt get too hot. I know somebody running 30 psi on a vnt 300tdi and has been for about a year and he races his truck. But like i said time will tell, if im on here looking for a good second hand engine you will guess whats happend )) How long have you been running 20 psi? Quote Link to comment Share on other sites More sharing options...
BogMonster Posted August 3, 2012 Share Posted August 3, 2012 Boom Quote Link to comment Share on other sites More sharing options...
discomikey Posted August 4, 2012 Share Posted August 4, 2012 I think its more the standard turbo rather than the engine itself that wont take the boost its too small and will become inefficient causing lots of heat. The big vnt will handle the high boost easily and as long as its not overfueled it shouldnt get too hot. I know somebody running 30 psi on a vnt 300tdi and has been for about a year and he races his truck. But like i said time will tell, if im on here looking for a good second hand engine you will guess whats happend )) How long have you been running 20 psi? he must have either a lot of luck, or a head studding kit on his then (which is likely if he races it. the turbo's are good to over 25psi without excessive EGT's. but i wouldnt try it on a TDI. ive been running it at that for over 2 years no problem, doing a lot of heavy towing mand making it struggle nicely overfuelled aswell to suit. but actually, its underfuelling that raises combustion temperature more than anything. Quote Link to comment Share on other sites More sharing options...
dave t Posted August 4, 2012 Author Share Posted August 4, 2012 he must have either a lot of luck, or a head studding kit on his then (which is likely if he races it. the turbo's are good to over 25psi without excessive EGT's. but i wouldnt try it on a TDI. ive been running it at that for over 2 years no problem, doing a lot of heavy towing mand making it struggle nicely overfuelled aswell to suit. but actually, its underfuelling that raises combustion temperature more than anything. Mine only peaks at 24psi very occasionally most of the time it runs at about 12psi, I can cruise the motorway at 80mph at about 2900rpm and boost is at 12 psi. If I overtake boost goes up to about 20-22psi and Im past the car in front and back down to 12psi. I dont tow or carry heavy loads so most of my driving is on very light throttle and fuel economy is very good at around 35mpg i though it was the other way around, if you underfuel the boost you get more air than fuel so the EGTs are lower, there is a lot of stuff on this on the Aussie forum I can certinally alter boost pressure by changing the fuelling. example if it will boost up to 30 psi turn the main fuel screw back a quarter of a turn and I will only get about 22-24psi I am only a newbie at all of this but its an interest of mine hence the experiments cheers Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted August 5, 2012 Share Posted August 5, 2012 but actually, its underfuelling that raises combustion temperature more than anything. Does your TDi run on petrol then??? Underfueling a diesel just makes it run at lower RPM over fueling it makes it melt. Quote Link to comment Share on other sites More sharing options...
dave t Posted August 5, 2012 Author Share Posted August 5, 2012 Does your TDi run on petrol then??? Underfueling a diesel just makes it run at lower RPM over fueling it makes it melt. thats an interesting point, I noticed the drop in boost pressure when I backed off the fueling but didnt notice a drop in rpm! will have to have a play with that Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted August 5, 2012 Share Posted August 5, 2012 thats an interesting point, I noticed the drop in boost pressure when I backed off the fueling but didnt notice a drop in rpm! will have to have a play with that RPM wont change from fuel settings because your not altering the mechanical govenor's settings.. What will sometimes change is the idle speed if you alter the max fuel screw. Boost depends on Exhaust gas quantity and velocity.... that depends on engine load and RPM. Quote Link to comment Share on other sites More sharing options...
discomikey Posted August 5, 2012 Share Posted August 5, 2012 bomber youre right in the sense of overall fuelling, but a lean diesel (mainly because timing is out) will run hotter too, whereas a rich mixture tends to run a bit cooler. melting pistons is more to do with how hot the driver lets the engine get (coolant issues/intercooler not upto it) what you really want for more power is LPG or propane dual fuel injection! but then you will melt pistons if you let it tick over on dual fuel. Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted August 5, 2012 Share Posted August 5, 2012 Or water injection as I did.... Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted August 5, 2012 Share Posted August 5, 2012 Or water injection as I did.... water spray your intercooler as well. Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted August 5, 2012 Share Posted August 5, 2012 but a lean diesel (mainly because timing is out) will run hotter too, whereas a rich mixture tends to run a bit cooler. melting pistons is more to do with how hot the driver lets the engine get (coolant issues/intercooler not upto it) Timing doesnt affect the fuel quantity injected, just the time when the fuel is injected. If advance you the timing, you get higher cylinder pressures but slower turbo spool, retard the timing you get the opposite. The damage is caused when you get the flame head to close to the piston crown. Quote Link to comment Share on other sites More sharing options...
Snagger Posted August 8, 2012 Share Posted August 8, 2012 The engine power/rpm is controlled by adjusting the mixture - it'll have some effects on temperature, but you don't get the issues that petrol engines do. As Vulcan says, big performance and temperature issues come from timing faults, with high temperatures and black smoke being associated with advanced injection and lower temperatures and white smoke from retarded injection. Retard it too much and you'll burn the exhaust valve and seat, and maybe damage the turbo too. Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted August 8, 2012 Share Posted August 8, 2012 One very noticeable difference between petrol and diesel engines is how they react to being mistimed. You get a diesel just a little out and it won't start whereas some petrol engines (the LR 2.25 being a case in point) you can get the timing miles out and it still starts and runs after a fashion. Anyone who has put the timing belt on a diesel one tooth out on the crank will know what I mean .... Quote Link to comment Share on other sites More sharing options...
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