Superdiesel D722 being turboed

[alexanderfoti]

Hi all

The superdream with the D722 is off being turboed now.

Its having a custom exhaust manifold made, and it will bring up the turbo to the right hand side, next to where the original water pump.

When It gets back, I will need to do intake pipework, and oil feed, then let it rip!!

I am not going with an intercooler for the moment, but will see, as space is super limited.

I will post pictures when I get a chance.

[Diesel Dave]

Cool idea but make sure you monitor the oil pressure as some turbos need a restriction after the blower otherwise it will bleed away all the pressure and then kiss your crank goodbye.

[alexanderfoti]

Thanks, will do.

Pretty sure this turbo has a restrictor in the supply side, but will double check.

[alexanderfoti]

Bike is back from the exhaust fabricator. Now sporting a nice shiny turbo bolted to the side.

They have done an excellent job as always. I will post pictures up tomorrow:

Things to do:

1. Rotate turbo cartridge so that the oil feed is on the top!
2. Connect up oil feed and drain from oil pressure port and sump plug respectively
3. Design and 3d print flanges for inlet and outlet of comrpessor side, its very close to the engine side, so hoping to be able to clock the housing just right.
4. Connect outlet of turbo to inlet of engine and connect boost gauge
5. Test!!

[mark_in_manchester]

I don't know about an intercooler, but you may well need a plenum. It will only need to do about 15psi, so you could experiment with and without one - perhaps a petrol can? - before deciding on your intake-side pipework. I think a rule-of-thumb is to make it at least one pots-worth of volume, which is small for you and I (>331cc in my case - built into charade intake manifold as a cast-alloy box).

My injector pump uses a diaphragm to effectively turn up the smoke screw (max injected fuel volume) as the plenum pressure rises. In the absence of all that you might have to turn up your smoke screw and go easier with the throttle when there's no boost pressure.

[alexanderfoti]

Thanks Mark.

I did the numbers before hand, I believe that the inlet pipe work, combined with the original D722 inlet manifold should come up with more than 300cc's worth of air capacity.

I have some pics up now:



Yes, unfortunately I do not have a boost dependent "enrichment" so will have to fine tune the balance between off boost smoke and on boost power. I will leave it at its current setting for the moment and see how it rides etc. I think wastegate is set to 12psi, but is not adjustable unfrotunately, so will have to change that if it ends up making too much boost.

[mark_in_manchester]

Mine does about 12psi too, and it's a triple with only a little more capacity. So maybe in the right ballpark? If the waste gate linkage is external in any way, you can hang a spring off it in one direction or the other to change where it blows off - but I suspect you won't have to.

My throttle pulls an internal lever (connected to the 'metering sleeve') one way, via an internal spring. How far it can pull this lever is part-set by the smoke screw, part-set by the centrifugal governor (which pushes that lever the opposite way, as it spins up) and part-set by the plenum pressure diaphragm, which allows the throttle / spring more leeway by withdrawing a movable 'stop' as plenum pressure rises. Landrover boy-racers (who knew) apparently use a stronger spring between the throttle linkage and that internal lever, which means the governor is less effective, and also mess with the stop on the plenum diaphragm to allow more fuel in as boost pressure rises. I suspect if I did that my economy would drop right off and I'd burst the rubber donut in the final drive line. Well, I might have a play one day - I bought a cheap Chinese exhaust temp sender / gauge on ebay in order to attempt to do so without melting anything. That might be an idea for you too - <£15 delivered.

[alexanderfoti]

So inlet and pipework completed.

On the first test run, it made 2-3 psi. As I have been testing it more and more, I am progressively seeing more and more boost. I have a 100% leak free intake system, tested up to 15PSI, so I am wondering why I am not seeing that much boost.

I have a feeling its the poor quality cheapo chinese IHI clone. I wonder if the progressively higher boost numbers are the bearings in the turbo loosening up.

I have a concerining amount of oil on the compressor side, Maybe 5-10ml after 30 mins of riding. I will keep a close eye on that as I would hate to have a runaway!

Initial test ride seems that its a bit peppier!

[mark_in_manchester]

On mine I have to rev it with quite a load on - that is, be generating some exhaust gasses! - before I see much boost. But it does sound like you're not quite there yet. I've had a leaky waste-gate do that to me - can you wire it shut for experimental purposes?

If it runs away, be ready to stuff your glove into the air intake - without your hand in it

[alexanderfoti]

OK lots of progress since last time.

I wedged the waste gate shut and it didn't make a difference. I have now managed to ride it a bit more, with a boost gauge attached permanently.

Leaving the fuel for the correct setting for an na engine, it makes around 3psi @ 3600 rpm with a big load on it.

Turning the fuel screw out 1 1/2 turns, gives lots of smoke off boost and about 4.5 psi on boost, there is a happy medium at around 4psi, but I feel like the bikes economy will drop off sharply with all the unburnt fuel going out of the exhaust.

It would be good to see if I can fabricate a fuel compensation mechanism that turns the fuel limit screw whilst on boost. I wonder if I can remove the grub screw without dropping things inside the engine case.

[alexanderfoti]

I have done a bit more testing.

A small crack in the feed pipe to the turbo has now been welded up. This has resolved that.

The pipe to the boost gauge was partially blocked with oil, this has now been sorted. I am seeing 5.5-6 PSI at 3700 RPM with the wastgate hose disconnected. I think that is pretty good considering. More than enough without an intercooler

Time will tell for fuel economy.

[Diesel Dave]

Excellent stuff, keep it coming.

[mark_in_manchester]

That sounds really good. I broke a (nice) pressure gauge by exposing it to pulsations in the pressure line - blokes at the diesel museum where I volunteer suggested a 'snubber', which is a small bit of something with a very small hole in it. If there was DC flow this would drop pressure like an orifice plate, but there isn't so it doesn't, just smooths out the vibes and gives the springy (bourdon) tube in the gauge an easier life. Should be dry in there though - wonder where the oil came from?

[mark_in_manchester]

(Your post reminds me I really need to make a rev counter. Tacho pulses come from the injector pump for me, and it has to be electronic and home-brew, which is putting me off!)

[Cossack]

I suspect if I did that my economy would drop right off and I'd burst the rubber donut in the final drive line.

http://www.ural-dnepr.net/wbb3/index.ph ... &pageNo=14 Message 277 mentions an Industrial Hardy coupling to replace the Russian one.

Otherwise this UK company could probably make you one http://www.gmspolymer.co.uk/flexible-couplings.htm Given the origins of the M-72 I wouldn't be surprised to find the coupling is from an Austin Seven.

[mark_in_manchester]

I wonder what that industrial coupling is - it would be interesting to find it. The link you posted is interesting too. The UJ in the Ural drive line is available as a steering part (!) something like GU1944, so enormous torque is not expected!

Regarding M72, yes it will be Austin 7 era - but I think the consensus now is that M72 productions lines came from Germany in 1939-ish as part of the Ribbentrop pact.