Ultimate Street Sleeper - Mercedes W124 'Superturbodiesel'
Discussion
andyps said:
On the basis the first picture seen on that link is the car throwing out enough smoke to get it removed from road use pretty quickly if seen by VOSA there isn't a great deal of credibility in it for me.
.
I really really am giving up with this thread. And quite possibly my life..
xjay1337 said:
andyps said:
On the basis the first picture seen on that link is the car throwing out enough smoke to get it removed from road use pretty quickly if seen by VOSA there isn't a great deal of credibility in it for me.
.
I really really am giving up with this thread. And quite possibly my life..
xjay1337 said:
andyps said:
On the basis the first picture seen on that link is the car throwing out enough smoke to get it removed from road use pretty quickly if seen by VOSA there isn't a great deal of credibility in it for me.
.
I really really am giving up with this thread. And quite possibly my life..
Edited by andyps on Sunday 7th February 13:20
Max_Torque said:
Firstly, the OP has addmitted that this engine has never actually been to 8krpm. He (eventually) said that it was just the fuel pump has been tested to 8k (of course, he means the fuel pump has been tested to 4krpm, as being a 4 stroke, the pump is geared 2:1 to the crank. i.e. the crank would have to be doing 16krpm to drive the pump at 8k.....) .
Lets look at all the other evidence:
1) i've never seen a single "pure" diesel engine (ie no extra fuel from propane or whatever) make peak power above 5500rpm. If you take the theoretical maximum flame speed, calculate the burn rate for an optimum chamber (with optimum turbulence) then funnily enough, you get peak power at a max of 5500rpm.
2) Being DI or IDI doesn't matter. You have to create peak cylinder pressure at the optimum reciprocating geometry, which depends on crank stroke and rod length, but usually is say around 12degCA ATDC. As you can't instantaneously burn the fuel charge (even in a gasoline engine, which relies on moving the point of spark ignition to optimise the Pmax crank angle) you have to start burning the charge early. And the more charge you have to burn per firing event, the earlier you have to start. With an IDI you could start to inject the fuel very early indeed, but it doesn't actually help for two reasons:
a) it won't actually ignite till sufficient enthalpy exists, which only happens as the rising piston compresses the charge and heats it sufficiently. (so inject early, and that fuel sits around in a wet puddle, doesn't even burn when finally it gets hot enough, as just comes out the exhaust as black smoke. (look familiar anyone??)
b) If you burn the fuel early, your cylinder pressure is increasing on the compression stroke (because the mean heat release (10-90MBF (Mass Burn Fraction)) has been moved forwards (in terms of crank angle). Increasing pressure on the compression stroke reduces torque.
Those two factors are the fundamental reason diesels are effectively self limiting in terms of the engine speed at which peak power is generated. It's also why engines designed to make the most power possible have a large cylinder count (for a low swept volume per cylinder) burning their fuel in lots of small short bangs and not a few long big ones.
Now lets look at BMEP (Brake Mean Effective Pressure)
The highest power std OM606 according to Wiki( don't shoot me if this is wrong) makes 130 kW @4400rpm and 330 Nm @1600 rpm.
Peak Power = 12 bar
Peak Torque = 13.8 bar
These are reasonable, if slightly average figures for an IDI engine designed in the early 1990's
Lets look at the current most power full production diesel, BMW's 3.0 M550d, which makes 280kW @4000rpm and 740Nm @2000rpm.
Peak Power = 28 bar
Peak Torque= 32.5 bar
These are very very good figures and the amount of mechanical design (to get the necessary strength to support those pressures and thermal loads) and combustion optmisation to burn that amount of fuel cleanly is world class (hence not every manufacturer has a diesel engine that powerful!!)
Lets compare then, those two benchmarks to the OPs claims of 562 or 680bhp. For the moment, lets assume the chassis rolls power graph he posted is accurate, reproduced below:
The engine is shown to make a very narrow band of peak power, with what i'd suggest is peak torque of 586lbft (794Nm) at 5000rpm, and peak power 562bhp(419kW) at approx 5100rpm. He also claims these figures are wheel figures and that the flywheel figure is 680bhp (506kW) (obviously no details of the method of estimating flyhweel power are given)
Peak Torque, 794Nm @ 5000rpm = 33.3 bar
Peak Power, 562bhp @ 5100rpm = 32.8 bar
Peak Power, 680bhp @ 5100rpm = 39.9 bar
So dear readers, i'll leave it up to you to decide what you think about those figures, but here are some questions to ask yourself:
1) On std internals, would an engine designed for 12/13.8 bar BMEP support 33.3/39.9 bar?
2) Is it likely that the combustion system on a 30 y/o engine is capable of making more BMEP at peak power (5krpm) than the current best ever production diesel engine can make at peak torque (2000rpm)?
An extra interesting analysis that can be performed is to calculate the Brake Specific Air Consumption (BSAC) figures that would be necessary to support the claimed performance of the OP's engine (all the data is there in the graph to allow you to estimate it fairly well). I'll leave it to the interested reader to do that, but by my calc's, the in order to make 680bhp, the OP's (mostly standard, 30year old) engine is slightly more efficient than the current crop of Hybrid F1 engines...........
Now, i'm all for people tuning and modifying their cars, but lets keep it real eh, and unfortunately, physics doesn't lie....... ;-)
That's all just science though, what does any of that prove?Lets look at all the other evidence:
1) i've never seen a single "pure" diesel engine (ie no extra fuel from propane or whatever) make peak power above 5500rpm. If you take the theoretical maximum flame speed, calculate the burn rate for an optimum chamber (with optimum turbulence) then funnily enough, you get peak power at a max of 5500rpm.
2) Being DI or IDI doesn't matter. You have to create peak cylinder pressure at the optimum reciprocating geometry, which depends on crank stroke and rod length, but usually is say around 12degCA ATDC. As you can't instantaneously burn the fuel charge (even in a gasoline engine, which relies on moving the point of spark ignition to optimise the Pmax crank angle) you have to start burning the charge early. And the more charge you have to burn per firing event, the earlier you have to start. With an IDI you could start to inject the fuel very early indeed, but it doesn't actually help for two reasons:
a) it won't actually ignite till sufficient enthalpy exists, which only happens as the rising piston compresses the charge and heats it sufficiently. (so inject early, and that fuel sits around in a wet puddle, doesn't even burn when finally it gets hot enough, as just comes out the exhaust as black smoke. (look familiar anyone??)
b) If you burn the fuel early, your cylinder pressure is increasing on the compression stroke (because the mean heat release (10-90MBF (Mass Burn Fraction)) has been moved forwards (in terms of crank angle). Increasing pressure on the compression stroke reduces torque.
Those two factors are the fundamental reason diesels are effectively self limiting in terms of the engine speed at which peak power is generated. It's also why engines designed to make the most power possible have a large cylinder count (for a low swept volume per cylinder) burning their fuel in lots of small short bangs and not a few long big ones.
Now lets look at BMEP (Brake Mean Effective Pressure)
The highest power std OM606 according to Wiki( don't shoot me if this is wrong) makes 130 kW @4400rpm and 330 Nm @1600 rpm.
Peak Power = 12 bar
Peak Torque = 13.8 bar
These are reasonable, if slightly average figures for an IDI engine designed in the early 1990's
Lets look at the current most power full production diesel, BMW's 3.0 M550d, which makes 280kW @4000rpm and 740Nm @2000rpm.
Peak Power = 28 bar
Peak Torque= 32.5 bar
These are very very good figures and the amount of mechanical design (to get the necessary strength to support those pressures and thermal loads) and combustion optmisation to burn that amount of fuel cleanly is world class (hence not every manufacturer has a diesel engine that powerful!!)
Lets compare then, those two benchmarks to the OPs claims of 562 or 680bhp. For the moment, lets assume the chassis rolls power graph he posted is accurate, reproduced below:
The engine is shown to make a very narrow band of peak power, with what i'd suggest is peak torque of 586lbft (794Nm) at 5000rpm, and peak power 562bhp(419kW) at approx 5100rpm. He also claims these figures are wheel figures and that the flywheel figure is 680bhp (506kW) (obviously no details of the method of estimating flyhweel power are given)
Peak Torque, 794Nm @ 5000rpm = 33.3 bar
Peak Power, 562bhp @ 5100rpm = 32.8 bar
Peak Power, 680bhp @ 5100rpm = 39.9 bar
So dear readers, i'll leave it up to you to decide what you think about those figures, but here are some questions to ask yourself:
1) On std internals, would an engine designed for 12/13.8 bar BMEP support 33.3/39.9 bar?
2) Is it likely that the combustion system on a 30 y/o engine is capable of making more BMEP at peak power (5krpm) than the current best ever production diesel engine can make at peak torque (2000rpm)?
An extra interesting analysis that can be performed is to calculate the Brake Specific Air Consumption (BSAC) figures that would be necessary to support the claimed performance of the OP's engine (all the data is there in the graph to allow you to estimate it fairly well). I'll leave it to the interested reader to do that, but by my calc's, the in order to make 680bhp, the OP's (mostly standard, 30year old) engine is slightly more efficient than the current crop of Hybrid F1 engines...........
Now, i'm all for people tuning and modifying their cars, but lets keep it real eh, and unfortunately, physics doesn't lie....... ;-)
egomeister said:
Max_Torque said:
Firstly, the OP has addmitted that this engine has never actually been to 8krpm. He (eventually) said that it was just the fuel pump has been tested to 8k (of course, he means the fuel pump has been tested to 4krpm, as being a 4 stroke, the pump is geared 2:1 to the crank. i.e. the crank would have to be doing 16krpm to drive the pump at 8k.....) .
Lets look at all the other evidence:
1) i've never seen a single "pure" diesel engine (ie no extra fuel from propane or whatever) make peak power above 5500rpm. If you take the theoretical maximum flame speed, calculate the burn rate for an optimum chamber (with optimum turbulence) then funnily enough, you get peak power at a max of 5500rpm.
2) Being DI or IDI doesn't matter. You have to create peak cylinder pressure at the optimum reciprocating geometry, which depends on crank stroke and rod length, but usually is say around 12degCA ATDC. As you can't instantaneously burn the fuel charge (even in a gasoline engine, which relies on moving the point of spark ignition to optimise the Pmax crank angle) you have to start burning the charge early. And the more charge you have to burn per firing event, the earlier you have to start. With an IDI you could start to inject the fuel very early indeed, but it doesn't actually help for two reasons:
a) it won't actually ignite till sufficient enthalpy exists, which only happens as the rising piston compresses the charge and heats it sufficiently. (so inject early, and that fuel sits around in a wet puddle, doesn't even burn when finally it gets hot enough, as just comes out the exhaust as black smoke. (look familiar anyone??)
b) If you burn the fuel early, your cylinder pressure is increasing on the compression stroke (because the mean heat release (10-90MBF (Mass Burn Fraction)) has been moved forwards (in terms of crank angle). Increasing pressure on the compression stroke reduces torque.
Those two factors are the fundamental reason diesels are effectively self limiting in terms of the engine speed at which peak power is generated. It's also why engines designed to make the most power possible have a large cylinder count (for a low swept volume per cylinder) burning their fuel in lots of small short bangs and not a few long big ones.
Now lets look at BMEP (Brake Mean Effective Pressure)
The highest power std OM606 according to Wiki( don't shoot me if this is wrong) makes 130 kW @4400rpm and 330 Nm @1600 rpm.
Peak Power = 12 bar
Peak Torque = 13.8 bar
These are reasonable, if slightly average figures for an IDI engine designed in the early 1990's
Lets look at the current most power full production diesel, BMW's 3.0 M550d, which makes 280kW @4000rpm and 740Nm @2000rpm.
Peak Power = 28 bar
Peak Torque= 32.5 bar
These are very very good figures and the amount of mechanical design (to get the necessary strength to support those pressures and thermal loads) and combustion optmisation to burn that amount of fuel cleanly is world class (hence not every manufacturer has a diesel engine that powerful!!)
Lets compare then, those two benchmarks to the OPs claims of 562 or 680bhp. For the moment, lets assume the chassis rolls power graph he posted is accurate, reproduced below:
The engine is shown to make a very narrow band of peak power, with what i'd suggest is peak torque of 586lbft (794Nm) at 5000rpm, and peak power 562bhp(419kW) at approx 5100rpm. He also claims these figures are wheel figures and that the flywheel figure is 680bhp (506kW) (obviously no details of the method of estimating flyhweel power are given)
Peak Torque, 794Nm @ 5000rpm = 33.3 bar
Peak Power, 562bhp @ 5100rpm = 32.8 bar
Peak Power, 680bhp @ 5100rpm = 39.9 bar
So dear readers, i'll leave it up to you to decide what you think about those figures, but here are some questions to ask yourself:
1) On std internals, would an engine designed for 12/13.8 bar BMEP support 33.3/39.9 bar?
2) Is it likely that the combustion system on a 30 y/o engine is capable of making more BMEP at peak power (5krpm) than the current best ever production diesel engine can make at peak torque (2000rpm)?
An extra interesting analysis that can be performed is to calculate the Brake Specific Air Consumption (BSAC) figures that would be necessary to support the claimed performance of the OP's engine (all the data is there in the graph to allow you to estimate it fairly well). I'll leave it to the interested reader to do that, but by my calc's, the in order to make 680bhp, the OP's (mostly standard, 30year old) engine is slightly more efficient than the current crop of Hybrid F1 engines...........
Now, i'm all for people tuning and modifying their cars, but lets keep it real eh, and unfortunately, physics doesn't lie....... ;-)
That's all just science though, what does any of that prove?Lets look at all the other evidence:
1) i've never seen a single "pure" diesel engine (ie no extra fuel from propane or whatever) make peak power above 5500rpm. If you take the theoretical maximum flame speed, calculate the burn rate for an optimum chamber (with optimum turbulence) then funnily enough, you get peak power at a max of 5500rpm.
2) Being DI or IDI doesn't matter. You have to create peak cylinder pressure at the optimum reciprocating geometry, which depends on crank stroke and rod length, but usually is say around 12degCA ATDC. As you can't instantaneously burn the fuel charge (even in a gasoline engine, which relies on moving the point of spark ignition to optimise the Pmax crank angle) you have to start burning the charge early. And the more charge you have to burn per firing event, the earlier you have to start. With an IDI you could start to inject the fuel very early indeed, but it doesn't actually help for two reasons:
a) it won't actually ignite till sufficient enthalpy exists, which only happens as the rising piston compresses the charge and heats it sufficiently. (so inject early, and that fuel sits around in a wet puddle, doesn't even burn when finally it gets hot enough, as just comes out the exhaust as black smoke. (look familiar anyone??)
b) If you burn the fuel early, your cylinder pressure is increasing on the compression stroke (because the mean heat release (10-90MBF (Mass Burn Fraction)) has been moved forwards (in terms of crank angle). Increasing pressure on the compression stroke reduces torque.
Those two factors are the fundamental reason diesels are effectively self limiting in terms of the engine speed at which peak power is generated. It's also why engines designed to make the most power possible have a large cylinder count (for a low swept volume per cylinder) burning their fuel in lots of small short bangs and not a few long big ones.
Now lets look at BMEP (Brake Mean Effective Pressure)
The highest power std OM606 according to Wiki( don't shoot me if this is wrong) makes 130 kW @4400rpm and 330 Nm @1600 rpm.
Peak Power = 12 bar
Peak Torque = 13.8 bar
These are reasonable, if slightly average figures for an IDI engine designed in the early 1990's
Lets look at the current most power full production diesel, BMW's 3.0 M550d, which makes 280kW @4000rpm and 740Nm @2000rpm.
Peak Power = 28 bar
Peak Torque= 32.5 bar
These are very very good figures and the amount of mechanical design (to get the necessary strength to support those pressures and thermal loads) and combustion optmisation to burn that amount of fuel cleanly is world class (hence not every manufacturer has a diesel engine that powerful!!)
Lets compare then, those two benchmarks to the OPs claims of 562 or 680bhp. For the moment, lets assume the chassis rolls power graph he posted is accurate, reproduced below:
The engine is shown to make a very narrow band of peak power, with what i'd suggest is peak torque of 586lbft (794Nm) at 5000rpm, and peak power 562bhp(419kW) at approx 5100rpm. He also claims these figures are wheel figures and that the flywheel figure is 680bhp (506kW) (obviously no details of the method of estimating flyhweel power are given)
Peak Torque, 794Nm @ 5000rpm = 33.3 bar
Peak Power, 562bhp @ 5100rpm = 32.8 bar
Peak Power, 680bhp @ 5100rpm = 39.9 bar
So dear readers, i'll leave it up to you to decide what you think about those figures, but here are some questions to ask yourself:
1) On std internals, would an engine designed for 12/13.8 bar BMEP support 33.3/39.9 bar?
2) Is it likely that the combustion system on a 30 y/o engine is capable of making more BMEP at peak power (5krpm) than the current best ever production diesel engine can make at peak torque (2000rpm)?
An extra interesting analysis that can be performed is to calculate the Brake Specific Air Consumption (BSAC) figures that would be necessary to support the claimed performance of the OP's engine (all the data is there in the graph to allow you to estimate it fairly well). I'll leave it to the interested reader to do that, but by my calc's, the in order to make 680bhp, the OP's (mostly standard, 30year old) engine is slightly more efficient than the current crop of Hybrid F1 engines...........
Now, i'm all for people tuning and modifying their cars, but lets keep it real eh, and unfortunately, physics doesn't lie....... ;-)
Somehow even with a safety factor of 2 on the materials, pushing 3 times the load through a 30 year old engine sounds like a recipe for explosions of the block at some point.
Given Maxtorque is using the baseline calcs for this (did engine design at university, so do have a grasp on it here), the numbers don't lie.
I can see these old mercs making good power, but not at this level, and even if it does? Bearings, rods and pistons will probably be making for the nearest exit soon via the sump or block sides, or more likely, the dyno used is out of calibration by a mile.
What about the argument about it raving to 8k?
It did seem unlikely to me if the engine is on standard internals. I mean diesels are simply not designed to rev that high and are generally under square. But looking at wikipedia;
https://en.wikipedia.org/wiki/Mercedes-Benz_OM606_...
It would appear that it's actually over square, which surprised me.
And the pistons don't look like they're as big as what I would expect a diesel piston to look like;
http://www.ebay.co.uk/itm/MERCEDES-BENZ-MB-2-5-3-0...
It seems almost credible, but then I think of the 3.2 v6 in my alfa, which red lines a 7k. It's designed to rev that high and the general view is that 7.5k is about the limit for standard internals....
It did seem unlikely to me if the engine is on standard internals. I mean diesels are simply not designed to rev that high and are generally under square. But looking at wikipedia;
https://en.wikipedia.org/wiki/Mercedes-Benz_OM606_...
It would appear that it's actually over square, which surprised me.
And the pistons don't look like they're as big as what I would expect a diesel piston to look like;
http://www.ebay.co.uk/itm/MERCEDES-BENZ-MB-2-5-3-0...
It seems almost credible, but then I think of the 3.2 v6 in my alfa, which red lines a 7k. It's designed to rev that high and the general view is that 7.5k is about the limit for standard internals....
Sf_Manta said:
egomeister said:
Max_Torque said:
Firstly, the OP has addmitted that this engine has never actually been to 8krpm. He (eventually) said that it was just the fuel pump has been tested to 8k (of course, he means the fuel pump has been tested to 4krpm, as being a 4 stroke, the pump is geared 2:1 to the crank. i.e. the crank would have to be doing 16krpm to drive the pump at 8k.....) .
Lets look at all the other evidence:
1) i've never seen a single "pure" diesel engine (ie no extra fuel from propane or whatever) make peak power above 5500rpm. If you take the theoretical maximum flame speed, calculate the burn rate for an optimum chamber (with optimum turbulence) then funnily enough, you get peak power at a max of 5500rpm.
2) Being DI or IDI doesn't matter. You have to create peak cylinder pressure at the optimum reciprocating geometry, which depends on crank stroke and rod length, but usually is say around 12degCA ATDC. As you can't instantaneously burn the fuel charge (even in a gasoline engine, which relies on moving the point of spark ignition to optimise the Pmax crank angle) you have to start burning the charge early. And the more charge you have to burn per firing event, the earlier you have to start. With an IDI you could start to inject the fuel very early indeed, but it doesn't actually help for two reasons:
a) it won't actually ignite till sufficient enthalpy exists, which only happens as the rising piston compresses the charge and heats it sufficiently. (so inject early, and that fuel sits around in a wet puddle, doesn't even burn when finally it gets hot enough, as just comes out the exhaust as black smoke. (look familiar anyone??)
b) If you burn the fuel early, your cylinder pressure is increasing on the compression stroke (because the mean heat release (10-90MBF (Mass Burn Fraction)) has been moved forwards (in terms of crank angle). Increasing pressure on the compression stroke reduces torque.
Those two factors are the fundamental reason diesels are effectively self limiting in terms of the engine speed at which peak power is generated. It's also why engines designed to make the most power possible have a large cylinder count (for a low swept volume per cylinder) burning their fuel in lots of small short bangs and not a few long big ones.
Now lets look at BMEP (Brake Mean Effective Pressure)
The highest power std OM606 according to Wiki( don't shoot me if this is wrong) makes 130 kW @4400rpm and 330 Nm @1600 rpm.
Peak Power = 12 bar
Peak Torque = 13.8 bar
These are reasonable, if slightly average figures for an IDI engine designed in the early 1990's
Lets look at the current most power full production diesel, BMW's 3.0 M550d, which makes 280kW @4000rpm and 740Nm @2000rpm.
Peak Power = 28 bar
Peak Torque= 32.5 bar
These are very very good figures and the amount of mechanical design (to get the necessary strength to support those pressures and thermal loads) and combustion optmisation to burn that amount of fuel cleanly is world class (hence not every manufacturer has a diesel engine that powerful!!)
Lets compare then, those two benchmarks to the OPs claims of 562 or 680bhp. For the moment, lets assume the chassis rolls power graph he posted is accurate, reproduced below:
The engine is shown to make a very narrow band of peak power, with what i'd suggest is peak torque of 586lbft (794Nm) at 5000rpm, and peak power 562bhp(419kW) at approx 5100rpm. He also claims these figures are wheel figures and that the flywheel figure is 680bhp (506kW) (obviously no details of the method of estimating flyhweel power are given)
Peak Torque, 794Nm @ 5000rpm = 33.3 bar
Peak Power, 562bhp @ 5100rpm = 32.8 bar
Peak Power, 680bhp @ 5100rpm = 39.9 bar
So dear readers, i'll leave it up to you to decide what you think about those figures, but here are some questions to ask yourself:
1) On std internals, would an engine designed for 12/13.8 bar BMEP support 33.3/39.9 bar?
2) Is it likely that the combustion system on a 30 y/o engine is capable of making more BMEP at peak power (5krpm) than the current best ever production diesel engine can make at peak torque (2000rpm)?
An extra interesting analysis that can be performed is to calculate the Brake Specific Air Consumption (BSAC) figures that would be necessary to support the claimed performance of the OP's engine (all the data is there in the graph to allow you to estimate it fairly well). I'll leave it to the interested reader to do that, but by my calc's, the in order to make 680bhp, the OP's (mostly standard, 30year old) engine is slightly more efficient than the current crop of Hybrid F1 engines...........
Now, i'm all for people tuning and modifying their cars, but lets keep it real eh, and unfortunately, physics doesn't lie....... ;-)
That's all just science though, what does any of that prove?Lets look at all the other evidence:
1) i've never seen a single "pure" diesel engine (ie no extra fuel from propane or whatever) make peak power above 5500rpm. If you take the theoretical maximum flame speed, calculate the burn rate for an optimum chamber (with optimum turbulence) then funnily enough, you get peak power at a max of 5500rpm.
2) Being DI or IDI doesn't matter. You have to create peak cylinder pressure at the optimum reciprocating geometry, which depends on crank stroke and rod length, but usually is say around 12degCA ATDC. As you can't instantaneously burn the fuel charge (even in a gasoline engine, which relies on moving the point of spark ignition to optimise the Pmax crank angle) you have to start burning the charge early. And the more charge you have to burn per firing event, the earlier you have to start. With an IDI you could start to inject the fuel very early indeed, but it doesn't actually help for two reasons:
a) it won't actually ignite till sufficient enthalpy exists, which only happens as the rising piston compresses the charge and heats it sufficiently. (so inject early, and that fuel sits around in a wet puddle, doesn't even burn when finally it gets hot enough, as just comes out the exhaust as black smoke. (look familiar anyone??)
b) If you burn the fuel early, your cylinder pressure is increasing on the compression stroke (because the mean heat release (10-90MBF (Mass Burn Fraction)) has been moved forwards (in terms of crank angle). Increasing pressure on the compression stroke reduces torque.
Those two factors are the fundamental reason diesels are effectively self limiting in terms of the engine speed at which peak power is generated. It's also why engines designed to make the most power possible have a large cylinder count (for a low swept volume per cylinder) burning their fuel in lots of small short bangs and not a few long big ones.
Now lets look at BMEP (Brake Mean Effective Pressure)
The highest power std OM606 according to Wiki( don't shoot me if this is wrong) makes 130 kW @4400rpm and 330 Nm @1600 rpm.
Peak Power = 12 bar
Peak Torque = 13.8 bar
These are reasonable, if slightly average figures for an IDI engine designed in the early 1990's
Lets look at the current most power full production diesel, BMW's 3.0 M550d, which makes 280kW @4000rpm and 740Nm @2000rpm.
Peak Power = 28 bar
Peak Torque= 32.5 bar
These are very very good figures and the amount of mechanical design (to get the necessary strength to support those pressures and thermal loads) and combustion optmisation to burn that amount of fuel cleanly is world class (hence not every manufacturer has a diesel engine that powerful!!)
Lets compare then, those two benchmarks to the OPs claims of 562 or 680bhp. For the moment, lets assume the chassis rolls power graph he posted is accurate, reproduced below:
The engine is shown to make a very narrow band of peak power, with what i'd suggest is peak torque of 586lbft (794Nm) at 5000rpm, and peak power 562bhp(419kW) at approx 5100rpm. He also claims these figures are wheel figures and that the flywheel figure is 680bhp (506kW) (obviously no details of the method of estimating flyhweel power are given)
Peak Torque, 794Nm @ 5000rpm = 33.3 bar
Peak Power, 562bhp @ 5100rpm = 32.8 bar
Peak Power, 680bhp @ 5100rpm = 39.9 bar
So dear readers, i'll leave it up to you to decide what you think about those figures, but here are some questions to ask yourself:
1) On std internals, would an engine designed for 12/13.8 bar BMEP support 33.3/39.9 bar?
2) Is it likely that the combustion system on a 30 y/o engine is capable of making more BMEP at peak power (5krpm) than the current best ever production diesel engine can make at peak torque (2000rpm)?
An extra interesting analysis that can be performed is to calculate the Brake Specific Air Consumption (BSAC) figures that would be necessary to support the claimed performance of the OP's engine (all the data is there in the graph to allow you to estimate it fairly well). I'll leave it to the interested reader to do that, but by my calc's, the in order to make 680bhp, the OP's (mostly standard, 30year old) engine is slightly more efficient than the current crop of Hybrid F1 engines...........
Now, i'm all for people tuning and modifying their cars, but lets keep it real eh, and unfortunately, physics doesn't lie....... ;-)
Somehow even with a safety factor of 2 on the materials, pushing 3 times the load through a 30 year old engine sounds like a recipe for explosions of the block at some point.
Given Maxtorque is using the baseline calcs for this (did engine design at university, so do have a grasp on it here), the numbers don't lie.
I can see these old mercs making good power, but not at this level, and even if it does? Bearings, rods and pistons will probably be making for the nearest exit soon via the sump or block sides, or more likely, the dyno used is out of calibration by a mile.
Did someone fit vtec to this one 
I think the truth falls somewhere between the science and the figures, it really needs to go on a dyno that is calibrated against a known factory car, say a 335D and see what that makes, then compare, it is obviously making very decent power, but 680 bhp seems a little bit far fetched, but I would love to see it confirmed.
I would have thought that much power and torque would destroy the rest of the drivetrain or just vapourise the tyres every time you put your foot down ?
I think the truth falls somewhere between the science and the figures, it really needs to go on a dyno that is calibrated against a known factory car, say a 335D and see what that makes, then compare, it is obviously making very decent power, but 680 bhp seems a little bit far fetched, but I would love to see it confirmed.
I would have thought that much power and torque would destroy the rest of the drivetrain or just vapourise the tyres every time you put your foot down ?
J4CKO said:
just vapourise the tyres every time you put your foot down ?
Looking at the various OM606 videos on YT, that's exactly what happens - all the way up through the gears. Freaky, perhaps, but surely it's worth making the changeover less brutal and having lower peak power? From a standing start, these conversions don't look too quick. Would be er... 'fun' being behind one of these on a PH drive-out, as it goes on and off boost with each corner.
VeeFource said:
Woah, an entire rational compressed into one tiny full stop. Shame I can't zoom in far enough to read it.
Can't be bothered really, however Mercedes are not into emissions cheating and never were so the .962 engines were fitted with hybrid EDC pumps that are IDI and don't smoke. These can easily be tuned to 400bhp+ With big fat torque curves.I suspect there is a lot of opinioneering in this thread and not that much engineering; more importantly experience of actually getting your hands dirty and building one and driving it about.
Good on the OP for buying an interesting car and not something straight out of a manufacturers showroom.
Palmers said:
The car made 562hp and 587 ft lb. That is wheel figures from a hub dyno. Crank figure was 680bhp. It has an 8,000rpm redline, but feels best when changing at around 6 to 6.5.
And yes, it will still do 37mpg if you stay off boost.
This thread looked promising until this utter rubbish! Diesels won't do 8k.And yes, it will still do 37mpg if you stay off boost.
EDIT: It looks like I'm a bit late to this party...
Edited by shalmaneser on Sunday 7th February 18:57
maxypriest said:
VeeFource said:
Woah, an entire rational compressed into one tiny full stop. Shame I can't zoom in far enough to read it.
Can't be bothered really, however Mercedes are not into emissions cheating and never were so the .962 engines were fitted with hybrid EDC pumps that are IDI and don't smoke. These can easily be tuned to 400bhp+ With big fat torque curves.I suspect there is a lot of opinioneering in this thread and not that much engineering; more importantly experience of actually getting your hands dirty and building one and driving it about.
Good on the OP for buying an interesting car and not something straight out of a manufacturers showroom.
PHers like MT are worth their weight in gold on this site so it really beggars belief how poorly they're treated. One day you'll start a thread to resolve a problem with your car and all you'll get back is a load of tosh because all the guys that really know what their talking about will have b¥€€£&£d off thanks to people like you. Thanks for spoiling it for the rest of us too btw!.
Just to add; I'm all for a bit of shed engineering and experimentation! Just not when these people start proclaiming they've beaten physics and the real Engineers haven't a clue.
Edited by VeeFource on Sunday 7th February 19:05
maxypriest said:
I suspect there is a lot of opinioneering in this thread and not that much engineering; more importantly experience of actually getting your hands dirty and building one and driving it about.
Well you suspect wrong......I've been doing "Hands on" engineering since i built my first car at the age of 13, and back in 1995 (can i politely ask how old were you in 1995 btw??) i built and tuned this MSA Comp Safari event / championship wining Land Rover that was powered by an iveco 2.5 turbo diesel:
In the 21 years since then i've built a lot of other vehicles, both for myself and friends and working for high performance vehicle/engine specalists like Cosworth and Prodive.
And don't think i'm alone in this. The vast majority of the very good engineers i meet on a professional level tend to be car enthusiasts with all sorts of amazing projects and "Hands on" experience ;-)
Edited by anonymous-user on Sunday 7th February 19:45
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