darrenjlobb's Adaptronic Managed Compound Blown Derv Bus Build

[darrenjlobb]

Sounds ace! (in the vids)

Thanks chap,

Sat watching this at 2am when i couldnt sleep. Just cant get my head around so much of it. You sir are one talented mofo [VICTORY HAND]

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Thanks mate, it all makes sence when you read the entire thread I think!

that is one hell of a beast/street-sleeper.
never knew a derv could rev so high.
most of the tech is above me but it's a great build.
correct me if i'm wrong, but it sound like it's 'hunting' a bit at idle. reminds me of the old lorries from years ago.

The car isnt actually revving that hard at the moment, its hitting my fuel cut limit at 5800rpm in all the videos, infact some of the first videos its hitting the limiter at 5200rpm. On the limits with durations so the power is rolling over around 5k at the moment due to simply not being able to get the fuel in any faster.

that's not high tbh, I'm sure Darren revved one of his old engines further, fairly commonplace for engines with more valves to rev higher, though the old M51 BMW inline 6 goes to 4800 and that's just a 12 valve.

its usually more a function of bore vs stroke plus rod lengths.

To 8 valves or 16 valves, diesels will revs, short stroke obviously helps, but more importantly than anything is the turbocharger / turbochargers ability to keep moving air as its required up there, and the injectors ability to get the fuel in fast enough without the durations getting out of hand up there. More RPM's will come with time.

Id have to sell the house to get insurance for that with a M9 postcode..what a build...The John Deere Missile...wonder if they would sponsor it?

Haha, I dont think Deere would  be massively impressed with the PSA powered machine tbh!

good going Mr Lobb keep at it

well done

Thanks Paul,

Not watched the video yet but it's awesome that in a week you've got so much licked and doubled the power output.
She's looking awesome in the photos. Can't be far from the road?

Cheers Chris, to be honest still a long way from the road, I see little point in wasting money insuring it / MOT'ing it and taxing it when its still in development. After tuning on the dyno, it has made me realise that any attempt to "tune" an engine on the road is largely next to useless, esp with this sort of build. So its better off staying on the rollers for the time being where I can keep a very close eye on everything thats going on, and use the logs / dyno to make progress.

Thouroughly enjoyed that write up and video ta, all impressive stuff and quite the achievment for a home-brew project!!!

That certainly looks like a very useable power output, should be a pussycat to drive where traction is limited hopefully? Guessing from the dyno graph that the rev cut is just shy of 7K so pretty high as dervs go.

No as above its hitting my fuel cut at 5800, this will increase in time, but right now fighting injector capacity more than anything! But she will scream once again soon! And yes, all still built in an ex calve rearing shed on a farm in Cornwall!

Read all of the last update,  watched the video.
I don't understand any of it but I do know it's pretty feckin' cool.

Thanks Danny!

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So another little update, looks like we are out of injector pretty much now. Have been slowly increasing power over the last week, and are now at the maximum rail pressure I can run with the current rail pressure sensor allowing some control overhead, but are hitting my "duration limiter" I set in the logic to make sure there are no accidental fails! 

Although we could get away with some extra duration in the mid range where is there is more time to get the fuel in, we are sat on the limiter up in the revs where we want to be making power. Here is a screen shot of the logs from a pull, in the top graph the white line shows current RPM, the yellow line shows requested fuel "mm3" after all correction maps, and the red line shows the injector duration (actual output) at the time, you will notice at around 4krpm the duration just hits the limiter (hence the flat line), so although the request continues to rise, the car will put no extra fuel in as its already at max rail pressure, and max duration. So little option now than to pull the injectors out and see about sorting some bigger hose pipes out. For reference, bottom graph is showing rail pressure in red, and MAP1 in green.




So this evening set about dropping the car off the Dyno, and pulling the injectors out:






Will be getting these sent off this week, initial plan is to increase the needle lift on one, and stick it back in a flow bench, and literally just run it up at 1800bar and see how much extra flow we can get from the current nozzles. Im thinking although it will be a significant increase, it will likely not be enough for what I have planned, so will likely be needing another set of nozzles, but we will have to wait and see on that. Sadly I have no means of setting up Common Rail injectors myself and / or flow testing them, so have to get it done externally, which is fairly expensive, so really need to try and get it right first time if I can. Have debated building my own common rail flow bench a few times, but for what it would cost to do a decent job, I could have a few sets done, and cant really justify the expense right now. 

Have noticed a couple minor oil leaks that need to be resolved also, so while the engine is apart will be able to take the time to change the oil, sort a few little leaks / niggles out and work on some other areas that still need sorting out!

Thanks for reading along