twin charged diesel mercedes

[mantahead]

hi,
hello i am new here.
i just read an interesting thread on here on valve spring pressure and boost.

i have built a diesel mercedes drift car with home built exhaust manifold, scania turbo(holset hx52, 13cm exhaust housing)eaton m112 supercharger. Engine is straight 6, 3 litre, 24 valve idi with mechanical Dieselmeken injector pump.

the problem i have is multiple misfire in low revs under load, light grey smoke followed by a pop and then as soon as the wheels break traction the engine clears and is sweet all the way to the redline.
If i remove the supercharger it is not near as bad but still there.
i think my problem is valve springs are not strong enough.
i overspeeded the supercharger to give me quick spool up for the turbo and bypass flap then opens and relieves the supercharger,i was running 2.66 drive ratio over crank, i then reduced it to 1.77 over crank.
Also i have a major overheating of coolant, although exhaust gas temps remain ok.
the supercharger feeds the turbo, then the turbo feeds the engine as normal, i think the small exhaust housing on the turbo(13cm)is restricting and causing back presssure in low rpm, the two external wastegates open at 2.1 bar

https://flic.kr/p/Ha8PzP

 

[moon161]

Have you tried STD-

http://www.superturbodiesel.com/std/

?
You should find a few people there familiar with dieselmeken pumps on 60x and 61x engines

Does the problem return when you lift return to low load/rpm?

 

[MikeHalloran]

Does your injection pump have an aneroid, or some other means of accepting data about manifold pressure or mass airflow? It should.


Mike Halloran
Pembroke Pines, FL, USA

 

[PackardV8]

Not valve springs - they'd get worse, not better as RPMs increase.

While I'm not familiar with that injection pump, a guess would be it doesn't have the proper cam profile to feed the boost curve you're generating at high load/low RPMs. When the wheels break traction, load decreases and RPMs rise, both moving past the fuel supply/load mismatch.

jack vines

 

[moon161]

And: Have you emailed or called Goran (the guy in finland that modifies these injector pumps)?

 

[mantahead]

hi,
yes the problem returns at low rpm but not if the rear wheels are still spinning, only under load before the traction breaks.

the pump has outside alda, (wastegate actuator mounted to stop lever on side of pump, controlled by boost presuure

when the problem occurs the engine isn't burning the fuel, as i get a big cloud of light grey smoke just after, like unburnt fuel and then a pop as she goes again, so i don't think it is a lean condition.

A few people on superturbodiesel where thinking valve spprings
thanks

 

[moon161]

The valve springs make no sense to me. Weak springs would cause valve float at hi rpms.

Non-combustion is exactly what I was thinking, like starting with some bad glow plugs or injectors, but that goes away as soon as those sustainer balls in the prechambers get hot.

A few questions come into my mind:
What is the boost at idle and before the wheels break?
If you put it in neutral and rev the motor, beyond a certain point?
Does playing with the idle regulator do anything?

 

[mantahead]

hi,
the first drive ratio i tried was 2.66 over crank, which give me 0.35 bar boost at idle(a bit greedy,lol)
next i tried 1.77 over crank speed, 0.15 bar at idle roughly.
i cant be sure of boost when she breaks traction.
is there far too much air trying to get through the engine and past that small exhaust housing, its only a 3 litre engine.
i can rev the engine no bother, all is sweet.
i can't screw idle speed up any or engine will run away. (this happened once and it blew the centre out of 2 glow plugs, engine survived)

first drive ratio video.

https://youtu.be/Umu1EMuNILY

 

[MikeHalloran]

Have you had a ring job since the runaway event?


Mike Halloran
Pembroke Pines, FL, USA

 

[moon161]

I like Mike's idea even though it sounds painful for the OP. Weak compression on a cylinder or two might produce this symptom. Maybe a compression or leakdown test will tell you something. But then, you say it goes away when you take the blower off.

I was thinking is there enough air mass flow at a low enough temperature to cool the sustainer balls in the prechambers at idle and low throttle?
If it ran away on you and burned a couple glo plugs, how are the prechambers?

Was that runaway off lube oil like you had to starve it of air to shut it down, or did cutting fuel via the IP at the shutdown button or ignition switch? If it ran up to the governed limit or went well over would inform your concerns about bearing wear or damage.

The fact that you can almost completely turn it off by removing the blower points away from any sort of engine damage though.

 

[mantahead]

hi,
sorry maybe i should have give more information, i had this condition on the last engine as well with a different set of injectors, the head gasket was blown, i changed the engine thinking it would cure the problem, head gasket is now away on current engine as well, very slight pressure in coolant, (did sniff test)
The heater plugs did not melt, just the centres got blown out

I have a major overheating problem on all engines, exhaust gas temperatures are under control but coolant temps are crazy after 2 laps, they start hitting 120c, then i cruise for 2 laps and get temps down and go again.

the other thing i did not mention was: the car was outside for a few months and water managed to get into the fuel and the engine run on the fuel for a short time, since then i completly flushed tank, run engine flushed again and changed fuel filters twice, since that i am on another engine.

 

[MikeHalloran]

Buy a bigger radiator, or at least a new stock unit.


Mike Halloran
Pembroke Pines, FL, USA

 

[voltech444]

You should look into water/methanol injection. This can lower your EGT's significantly and works very well when running boost. There's people who use 50/50 mixtures,and some that use only water. Water alone actually lowers EGT in diesel more if I recall correctly, where water/meth will add a little more power and boost MPG because the methanol increases the burn rate and ensures more complete combustion of the diesel fuel. AEM has some good kits. I'm more interested in using only water because it's cheaper; the main issue is ensuring your water reservior doesn't freeze. Don't waste your money on a cheap kit or u won't get good results.

 

[moon161]

Mike, the stock radiator for a W201 body would be sized for maybe 180 HP (the cosworth racing motor). I think our friend is making 2x that or more. But yeah, I think he's undercooled also.

 

[mantahead]

hi,
i know water meth is a great job for keeping the intake temps down but i would like to get rid of this mis- fire before i add anything more.
i'm using a driftworks alloy radiator that holds 4 litres of water.
i was thinking of putting a truck radiator in the boot.
I have wired up my Auber instruments device to my exhaust gas temperature sensor set at 600degrees c which sets off a large red led warning lamp, very rarely does this lamp light and only for a second, when the coolant temps get to about 120c.
so my egt's are not high but that supercharger is making hot air which must be boiling my coolant.

with no idle bypass my air temp coming out of the supercharger once saw 75 degrees c at idle after the car sat running for 10 minutes on a very hot day( in ireland lol, maybe 21c) although this air then goes through turbo and intercooler before entering engine.

its w202 mercedes c250td with e300td w210 engine.

the two wastegates on my exhaust manifold can relieve the back pressure at 2.1 bar but before that they can't which is were the problem occurs?

 

[mantahead]

[/url]IMG-20161205-WA0001.jpg by Wayne White, on Flickr]


IMG-20160508-WA0001.jpg by Wayne White, on Flickr

WP_20140310_003.jpg by Wayne White, on Flickr

 

[mantahead]

[/url]VID-20160627-WA0010.mp4 by Wayne White, on Flickr]

 

[MikeHalloran]

If you're going to run with the hood off anyway, you can get some free intercooling by adding fins to the outside of the tube running between the supercharger and the turbocompressor.

Dumb question: Electric fans commonly mount behind a radiator and pull air through it. Obviously there's no room to do that, but have you reversed the rotation of the motors or fitted pusher fans to blow air through the radiator?

Wrapping the headers that feed exhaust to the turbo might add a little power, and reduce radiant heating of, well, everything, including the radiator.

Awesome project. Have fun.


Mike Halloran
Pembroke Pines, FL, USA

 

[mantahead]

hi,
i tried different fans, the top pic you can see they are not at the front, i even tried mounting fans behind the intercooler to try and cool the air temps.
i am very tight for space as its 6 cylinder in there now instead of 5 and extra crank pulley for supercharger.
what do you think of putting the truck radiator in the boot(trunk), maybe more surface area to try and cool that water, its a good bit bigger than the alloy one but doesn't hold any more water, about 4 litres also?
Good point about the heat wrap, i noticed the alloy pipe gets very hot as its close to the radiator and the front header.

 

[mantahead]

hi,
not a great video but you can hear the pop at the start and again at 58 secs.

https://youtu.be/FFIfP5Y68z0