Ultimate Street Sleeper - Mercedes W124 'Superturbodiesel'
Discussion
Starting to chip away at little tasks.
My main bug was the interior. Wood was a nasty light coloured wood, and was pretty faded, cracked and just looked honking.
I got hold of some dark burl wood trim - but scratches, and small imperfections bug me (more than it should!)
So i got it hydro dripped in carbon
My main bug was the interior. Wood was a nasty light coloured wood, and was pretty faded, cracked and just looked honking.
I got hold of some dark burl wood trim - but scratches, and small imperfections bug me (more than it should!)
So i got it hydro dripped in carbon
Palmers said:
Starting to chip away at little tasks.
My main bug was the interior. Wood was a nasty light coloured wood, and was pretty faded, cracked and just looked honking.
I got hold of some dark burl wood trim - but scratches, and small imperfections bug me (more than it should!)
So i got it hydro dripped in carbon
That looks quite interesting, is there a part size minimum where that fails to work? My main bug was the interior. Wood was a nasty light coloured wood, and was pretty faded, cracked and just looked honking.
I got hold of some dark burl wood trim - but scratches, and small imperfections bug me (more than it should!)
So i got it hydro dripped in carbon
Palmers said:
Warmfuzzies said:
That looks quite interesting, is there a part size minimum where that fails to work?
I dont think so. Beats wrapping i think.Warmfuzzies said:
Absolutely, just been discussing it with daughter, as she's busy painting arrows, thought this might make a quicker neater alternative
Arrows for archery?Completely off topic but my mate runs this company:
https://www.arrowsocks.co.uk/
And gets used by Olympic level archers.
Back on topic - interior bits look good there in the hydro carbon, nothing worse than having bad wood.
Saw these crop up on a local selling site. Dont know if the guy knew their worth, as i got them at a steal. Needing a refurb, lacquer peel and light curbing. Geniune AMG monoblocks staggered 18x8 and 18x9. Guy was going to bin them!
Freshly painted
Ignore the scrap tyres on them, purchasing some new rubber soon!
Freshly painted
Ignore the scrap tyres on them, purchasing some new rubber soon!
Hello Palmers, the car looks great - a real sleeper. I must say I prefer those new alloys than the previous (or steel + trims)
Have you considered compound charging..?
diesel dragster here http://www.dieselworldmag.com/2064-2/
Was the question answered about running on veg oil? I waded through the pages of sadly negative comments but didn't notice a reply. Good job we all don't share such attitudes as no R&D would ever get done.
Have you considered compound charging..?
diesel dragster here http://www.dieselworldmag.com/2064-2/Was the question answered about running on veg oil? I waded through the pages of sadly negative comments but didn't notice a reply. Good job we all don't share such attitudes as no R&D would ever get done.
- DISCLAIMER FOR VEG OIL QUESTION*
This is a great thread. Thanks to the OP and maxypriest for articulating the real world experience of these cars, and to the skeptics for pointing out how unreliable dynos and marketing can be.
A few observations, and a question.
1. The OP was obviously led down a marketing path by people overstating the hp of the car he bought. But the car was going to have bonkers type power regardless, and far more than it can put down much of the time, which is all that matters pragmatically.
2. I dont think the OP is very savvy about injection pumps, but no need to go on about it.
3. I am no expert, but comparing an engine designed for a specific power level to an older engine designed for much less power and then modified to produce the same power is rather pointless in terms of the associated regulation-determined design envelope, which is completely bonkers on emissions and duty cycle in the first case, and nonexistent in the latter case. I dont recall the OP claiming anything about reliability or durability, but here he is being compared to a bunch of pro engineers at bmw. In fact even after grenading his motor, he just went out and purchased another one, rather than modifying the internals to sustain the (rather over) stated power level. This is a rather different durability target than bmw likely had in mind with the 550d motor.
Om606 pumps are routinely set at completely mad levels of fueling, resulting in totally unsafe egt and smoke levels, not to mention boost, which is nearly always inadequate for any sort of real world AFR at those fueling levels. The point dueselpumpuk would make is how long do you think you can actually operate the car at 500hp power output on a public road? And the answer is a few seconds at best before violating all sorts of laws. So they smoke befkre the turbo spools, and the egt is usually entirely unsafe for sustained operation, but the car is still shedloads of fun.
4. On this BMEP thing, somehow the Max Torque numbers appear to be off, because here is a 606 cranking out an honest 550 or so horses on an engine dyno, which should satisfy most armchair critics regarding drivetrain losses, wheel diameters, slippage and whatnot:
https://youtu.be/cS60QRf8X_s
To quote:
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)?
And the answer appears to be yes, at 550hp or so, for at least a short time, without any emissions or durability targets to meet, But there are examples of similar motors being driven on the street for tens of thousands of km without problems, suggesting the motor might actually be capable of more performance than a trained engineer would expect it to be capable of, which in turn should be no surprise, as we are pushing rather far beyond what a bunch of trained engineers at mercedes thought was reasonable also.
I do have an associated question for the professional engineers: Is compression generally lowered in high boost diesels to reduce peak cylinder pressures? And if so, are these peak cylinder pressures generally responsible for mechanical failure of rods etc? I am in the process of building one of these motors with a goal of 150cc/1000 and plan to boost it to 65psi or so, and I am consideting cutting the pistons down to lower the stock 22:1 to something more durable, but I would like to quantify the effect upon cylinder pressure and know whether it will actually make any difference to durability.
Thanks for any thoughts.
A few observations, and a question.
1. The OP was obviously led down a marketing path by people overstating the hp of the car he bought. But the car was going to have bonkers type power regardless, and far more than it can put down much of the time, which is all that matters pragmatically.
2. I dont think the OP is very savvy about injection pumps, but no need to go on about it.
3. I am no expert, but comparing an engine designed for a specific power level to an older engine designed for much less power and then modified to produce the same power is rather pointless in terms of the associated regulation-determined design envelope, which is completely bonkers on emissions and duty cycle in the first case, and nonexistent in the latter case. I dont recall the OP claiming anything about reliability or durability, but here he is being compared to a bunch of pro engineers at bmw. In fact even after grenading his motor, he just went out and purchased another one, rather than modifying the internals to sustain the (rather over) stated power level. This is a rather different durability target than bmw likely had in mind with the 550d motor.
Om606 pumps are routinely set at completely mad levels of fueling, resulting in totally unsafe egt and smoke levels, not to mention boost, which is nearly always inadequate for any sort of real world AFR at those fueling levels. The point dueselpumpuk would make is how long do you think you can actually operate the car at 500hp power output on a public road? And the answer is a few seconds at best before violating all sorts of laws. So they smoke befkre the turbo spools, and the egt is usually entirely unsafe for sustained operation, but the car is still shedloads of fun.
4. On this BMEP thing, somehow the Max Torque numbers appear to be off, because here is a 606 cranking out an honest 550 or so horses on an engine dyno, which should satisfy most armchair critics regarding drivetrain losses, wheel diameters, slippage and whatnot:
https://youtu.be/cS60QRf8X_s
To quote:
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)?
And the answer appears to be yes, at 550hp or so, for at least a short time, without any emissions or durability targets to meet, But there are examples of similar motors being driven on the street for tens of thousands of km without problems, suggesting the motor might actually be capable of more performance than a trained engineer would expect it to be capable of, which in turn should be no surprise, as we are pushing rather far beyond what a bunch of trained engineers at mercedes thought was reasonable also.
I do have an associated question for the professional engineers: Is compression generally lowered in high boost diesels to reduce peak cylinder pressures? And if so, are these peak cylinder pressures generally responsible for mechanical failure of rods etc? I am in the process of building one of these motors with a goal of 150cc/1000 and plan to boost it to 65psi or so, and I am consideting cutting the pistons down to lower the stock 22:1 to something more durable, but I would like to quantify the effect upon cylinder pressure and know whether it will actually make any difference to durability.
Thanks for any thoughts.
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....... ;-)
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....... ;-)
Personally I dont really care how much power it does/doesnt make, I like the idea and I am a big Merc fan, suffice to say it should be fairly brisk, I think the OP needs to get it on a drag strip, with 550 bhp, assuming its 1500 kilos or thereabouts, it should be in the 11's, I reckon as its not set up for drag racing it wouldn't get into the 11's but it would give a good indication of power.
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