Ultimate Street Sleeper - Mercedes W124 'Superturbodiesel'
Discussion
xjay1337 said:
Max_Torque said:
xjay1337 said:
Max_Torque said:
8000rpm. i think not. It ain't even gonna go past 5500. There's also precisely zero chance of it making a real 550bhp.
Why is that? Plenty of VW diesels have been modded to run that kind of RPM.
Not so much on common rail modern stuff but the older injection pump type diesels it's not uncommon.
Is it a fake 550bhp? Or are diesels just not very fast.
Compression ignition engines have a fundamental burn rate limitation, not present in gasoline engines (well it is present in gasoline engines but not to the point where it is a limitation normally (F1 engines at 20krpm were starting to hit it)
Regardless of where and how you burn the fuel, to make 600bhp you need a certain heat release, and that simply isn't possible in the time availible at high rpms. Take Audi's Le-Mans winning TDi, which makes peak power at, yup, you guessed it, 5000rpm. Do you think with the resources Audi an leverage they missed a trick, a simple way of making a diesel engine rev? Or what about BMW, or any other engine specalist from Recardo, AVL, Cosworth, or whoever?
Then Look at the (rather suspect) dyno graph the OP put up, showing his engine falling flat on it's face above about, oh look, 5000rpm. (hint, the torque is in freefall above just 5000rpm)) No way in the world is that going to rev to 8k rpm and make any more power.
Then we get to the fact he claims a std diesel engine that rev'd to probably around 4300rpm as standard can magically manage to go round at getting on for twice that speed? er, sorry, but nope again. Yeah, old Merc engines are robust, but they don't break the laws of physics, sorry.
And added to which 560bhp at 5krpm is 34bar BMEP. Again, yes those sorts of figures are possible, but not from a 25 year old diesel engine.
So, if you like to be bamboozled by Bulls
t, be my guest, but the OPs engine is not doing anything like the figures he claims.(Note 400 odd BHP at around 5krpm is more like it, and i'd bet my reputation (25 years of leading edge engine powertrain design) that the numbers will be around there if you tested the engine under properly controlled industry standard conditions)
BTW, old diesels drove the tacho off the alternator. If the belt ratio is changed the tacho will over read.
Typically on chassis rolls, the operator sets it up by checking what the tacho reads (as there are no plug leads to get an ignition trigger off) for the road speed and gear the car will be run in. Bingo, there's 25% more flywheel power, bang, just like that.......
And does an old merc diesel tacho even read to 8krpm? I'd suggest it doesn't. Or did he fit a petrol tacho, and was that properly re-calibrated to the engine?
Suspect as a suspect thing..........
Typically on chassis rolls, the operator sets it up by checking what the tacho reads (as there are no plug leads to get an ignition trigger off) for the road speed and gear the car will be run in. Bingo, there's 25% more flywheel power, bang, just like that.......
And does an old merc diesel tacho even read to 8krpm? I'd suggest it doesn't. Or did he fit a petrol tacho, and was that properly re-calibrated to the engine?
Suspect as a suspect thing..........
Finally, you see all that black smoke coming out the back? Do you know what that is?
It's UNBURNT fuel. Well here's the rub. If it ain't burning in the engine (which it isn't because there is no time for it to do so, even down t 5krpm (waaay short of the 8k claimed)) then it sure as st isn't adding power to the engine now is it??
It's UNBURNT fuel. Well here's the rub. If it ain't burning in the engine (which it isn't because there is no time for it to do so, even down t 5krpm (waaay short of the 8k claimed)) then it sure as s
t isn't adding power to the engine now is it??
OK lets clarify a few things.
Smoke - that clears up on full boost, its just as the boost comes in it smokes.
Power - It is a genuine 562whp. If you dont believe it feel free, it doesnt bother me.
Revs - It has an 8k rpm limit on the pump, its nothing to do with me reading the rev counter, thats what it was set to it on the test bench, and thats what it does. Im not saying i use it every gear change. As ive said it feels fastest going to 6-6.5k.
Remeber this is NOT a common rail, it is an indirect injection diesel running off a manual injection pump. There are no electrics / ecu involved.
Smoke - that clears up on full boost, its just as the boost comes in it smokes.
Power - It is a genuine 562whp. If you dont believe it feel free, it doesnt bother me.
Revs - It has an 8k rpm limit on the pump, its nothing to do with me reading the rev counter, thats what it was set to it on the test bench, and thats what it does. Im not saying i use it every gear change. As ive said it feels fastest going to 6-6.5k.
Remeber this is NOT a common rail, it is an indirect injection diesel running off a manual injection pump. There are no electrics / ecu involved.
Palmers said:
OK lets clarify a few things.
Smoke - that clears up on full boost, its just as the boost comes in it smokes.
Er, no it doesn't. The vids quite clearly show it smoking heavily all the way to the tested rpm (which was 5800rpm by the chassis rolls graph, if you believe the figures.)Smoke - that clears up on full boost, its just as the boost comes in it smokes.
Palmers said:
Power - It is a genuine 562whp. If you dont believe it feel free, it doesnt bother me.
Genuine? Er, lets see the calibration certificates, and the indenpendant witness for all the bits of equipment used. How did you calibrate the dyno speed etc? That's as about as genuine as me telling you i can fly.......Palmers said:
Revs - It has an 8k rpm limit on the pump, its nothing to do with me reading the rev counter, thats what it was set to it on the test bench, and thats what it does. Im not saying i use it every gear change. As ive said it feels fastest going to 6-6.5k.
Er, the fuel pump goes round HALF as fast as the crank, so you're now saying the engine can do 16krpm are you??From your own (highly suspect) dyno graph, torque is in free fall from just 5krpm, so it ain't going to be doing 6.5k, with any usefull power, let alone 8k.
Palmers said:
Remeber this is NOT a common rail, it is an indirect injection diesel running off a manual injection pump. There are no electrics / ecu involved.
Finally, this is the internet, you can claim anything you like and bamboozle most readers, but what actual vehicle performance is this capable of (ignore the claimed wheel power figures) what is its 0-100 or 1/4 mile time?
With a genuine 560bhp in a small car like that old merc, it should be sub 10 to 100 and do the quarter in a similar time.
I suspect however, it gets nowhere near those times......... In fact, i suspect you'd struggle to shake a 335d, even before that was "mapped" ;-)
With a genuine 560bhp in a small car like that old merc, it should be sub 10 to 100 and do the quarter in a similar time.
I suspect however, it gets nowhere near those times......... In fact, i suspect you'd struggle to shake a 335d, even before that was "mapped" ;-)
Edited by anonymous-user on Saturday 6th February 15:24
As a long-term owner of diesels (and a car nut who even considered chipping his own car, but then somebody showed me a piston from badly chipped car....), I would also have to express certain amount of distrust in these test results.
Allow me to give non-mechanical engineer explanation of this point of view...
- first, manual or electronic pump, it really doesn't matter - over 5000-5500 rpm I do believe a diesel engine can not burn required amount of fuel efficiently in time available, to make those torque figures. As Max Torque said, it's simply physics. It might be different with LPG conversion, actually running on max70% diesel-30% LPG mixture, but I am very hesitant to believe such a high-compression engine would last longer than one dyno run.
- second, torque is rotational equivalent of force, calculated by multiplaying vertical component of force acting on pistons and distance between centre of big end and crankshaft center. Since, this distance is fixed, only force can change. And to get that much torque increase (roughly FIVE TIMES standard figure), you need to increase force by creating MUCH HIGHER cylinder pressure. I don't believe even famous Merc engine can withstand it for long time...
- third, that gearbox is designed for, I would believe, max 450-500Nm of torque. So, if you are revving up to about 3750rpm, it's fine, but over that, something in the drivetrain would break...
And once again, anybody who finds a way to master a combustion process of a Diesel piston engine efficiently from 6000 to 8000rpm, will forever change an automotive history.
Just my opinion, mind you...
Allow me to give non-mechanical engineer explanation of this point of view...
- first, manual or electronic pump, it really doesn't matter - over 5000-5500 rpm I do believe a diesel engine can not burn required amount of fuel efficiently in time available, to make those torque figures. As Max Torque said, it's simply physics. It might be different with LPG conversion, actually running on max70% diesel-30% LPG mixture, but I am very hesitant to believe such a high-compression engine would last longer than one dyno run.
- second, torque is rotational equivalent of force, calculated by multiplaying vertical component of force acting on pistons and distance between centre of big end and crankshaft center. Since, this distance is fixed, only force can change. And to get that much torque increase (roughly FIVE TIMES standard figure), you need to increase force by creating MUCH HIGHER cylinder pressure. I don't believe even famous Merc engine can withstand it for long time...
- third, that gearbox is designed for, I would believe, max 450-500Nm of torque. So, if you are revving up to about 3750rpm, it's fine, but over that, something in the drivetrain would break...
And once again, anybody who finds a way to master a combustion process of a Diesel piston engine efficiently from 6000 to 8000rpm, will forever change an automotive history.
Just my opinion, mind you...
Well to be honest if your going to up the power on a 20+ year old engine emissions and durability takes a back seat (which I suspect the others would have realised).
This particular clip seems fairly quick: https://www.youtube.com/watch?v=ICqeREP8Je4
Besides one of these turning at 6k is epic
This particular clip seems fairly quick: https://www.youtube.com/watch?v=ICqeREP8Je4
Besides one of these turning at 6k is epic
A quick bit of googling suggest that W124 diesel tacho's read up to either 5krpm (early cars) or 6Krpm (later cars). The tacho's fitted to the gasoline engine'd versions read to 7k. None read to 8k.
And re-reading the OP's first post i now see the 560bhp figure is claimed to be wheel power figure, and that the engine makes 680bhp. LOL, and i'm the king of england.......
Which is all a bit of a pity, because i really like this car and what has been done to it. If you remove the bullst filter, a W124 with a genuine 400ish bhp sounds like a laugh, and a fun car. it doesn't need the internet bull to make it cool........
And re-reading the OP's first post i now see the 560bhp figure is claimed to be wheel power figure, and that the engine makes 680bhp. LOL, and i'm the king of england.......
Which is all a bit of a pity, because i really like this car and what has been done to it. If you remove the bulls
t filter, a W124 with a genuine 400ish bhp sounds like a laugh, and a fun car. it doesn't need the internet bull to make it cool........Max_Torque said:
Then we get to the fact he claims a std diesel engine that rev'd to probably around 4300rpm as standard can magically manage to go round at getting on for twice that speed? er, sorry, but nope again. Yeah, old Merc engines are robust, but they don't break the laws of physics, sorry.
You sound like you know your stuff.Just take note that the old Merc diesels with mechanical IP will happily Rev a lot higher than 4300rpm.
Clocks show 6000rpm and I've had an old 300D in standard guise right round off the top of the tach.
donaircooleone said:
Well to be honest if your going to up the power on a 20+ year old engine emissions and durability takes a back seat (which I suspect the others would have realised).
This particular clip seems fairly quick: https://www.youtube.com/watch?v=ICqeREP8Je4
Besides one of these turning at 6k is epic
No one isn't say these can't make decent power, say a genuine 400 or perhaps even 450bhp, or that that they won't "rev" to say 6krpm, but i am saying that they will make peak power at about 5 to 5.5krpm (as shown in the OPS graph and in that video where he shifts at 5.5krpm, except for when it momentarily wheelspins up to 6k) and no higher, and certainly 680bhp at 8krpm is total ballcrocks...... This particular clip seems fairly quick: https://www.youtube.com/watch?v=ICqeREP8Je4
Besides one of these turning at 6k is epic
Palmers said:
Did i say it makes 562 whp @ 8krpm? No. I posted the graph. As i said many times, it can rev to 8k. But feels best at 6 - 6.5.
If you dont believe me fine, like ive said its not bothering me.
Just stop cluttering my thread up with your drivel.
Max Torque certainly knows his stuff, however of late had become a sanctimonious knob about stuff lately, clearly has been doing night school at LoonR1s school of tact.If you dont believe me fine, like ive said its not bothering me.
Just stop cluttering my thread up with your drivel.
Gorbyrev said:
What a pleasing lack of DERV haters on this thread. Lovely beast you have there. How do you stop it starting to use the engine oil as fuel at high revs and lunch itself as it revs out of control?
I don't like diesels, for all the usual reasons, but this is really impressive and entertaining. Reminds me of https://m.youtube.com/watch?v=24afjVqm2Uw
RemyMartin said:
Palmers said:
Did i say it makes 562 whp @ 8krpm? No. I posted the graph. As i said many times, it can rev to 8k. But feels best at 6 - 6.5.
If you don't believe me fine, like ive said its not bothering me.
Just stop cluttering my thread up with your drivel.
Max Torque certainly knows his stuff, however of late had become a sanctimonious knob about stuff lately, clearly has been doing night school at LoonR1s school of tact.If you don't believe me fine, like ive said its not bothering me.
Just stop cluttering my thread up with your drivel.
There are plenty of forums where people with silly hair and caps on backwards shout about how there car has a milion bhp and how they fitted an K&N filter to get it, but this isn't one of those forums and it's all the better for it!
The comedy fact is that threads like this show that unfortunately people believe there own bull, without any actual facts to back it up.
If you could get 680bhp from a diesel engine via the simple expedient of bolting on a big turbo and re-stroking the injection pump, don't you think it would have been done a lot more? Wouldn't it be weird for proper motorsport teams to be wasting millions of pounds on state of the art ultra high performance diesel engines like the Audi Le Mans Tdi engine (that cost 50M to develop and makes a paltry 600bhp) when they could just buy an old W124 engine for £100 and spend another £1k on a big turbo and pump???
The phrase "too good to be true" exists because, things like this are, in fact, too good to be true, despite what might be claimed.
And like i said, i like this car, i like the idea of a sleeper W124 diesel, but i don't like people talking sh*te with no basis in fact................
Palmers said:
People once thought the world was flat.
er, and it was science and engineering that PROVED it wasn't. (not people sat around going, "it's flat because i say it is")Palmers said:
If you don't beliive it, fine. Like i said ALREADY, stop commenting.
This is a car forum. You Post, people comment. If you don't like the comments, don't post.Edited by anonymous-user on Saturday 6th February 17:43
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