Maverik Posted December 21, 2021 Author Share Posted December 21, 2021 4 hours ago, Mo Murphy said: Is this the point where you say I'm not throwing any more money down this particular hole, I'll put a TD5 in ? Mo Indeed... I might have got a devious plan waiting in the wings... along with many other projects... Quote Link to comment Share on other sites More sharing options...
Maverik Posted December 21, 2021 Author Share Posted December 21, 2021 Took it out and did the same, spiked up then ran within expected parameters. Something interesting though is it appears its the fueling that controls the max boost pressure, which I was struggling to get my head around, as the standard boost pin must be under fueling compared to the other pin as my max boost was limited to 1.2-1.3bar as opposed to 1.45. I'll run it a bit more like this and see if its still does the sticking thing, and when the new gauge comes I'll test the actuator and turbo again. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted December 21, 2021 Share Posted December 21, 2021 More fuel equals more hot expanded gas equals more energy to spool the turbo. 2 Quote Link to comment Share on other sites More sharing options...
Snagger Posted December 21, 2021 Share Posted December 21, 2021 In the words of Dave Bowman, “It’s all connected. Everything”. As Bowie says, more fuel = more burn =more exhaust energy = more boost = more fuel and around and around… Quote Link to comment Share on other sites More sharing options...
Maverik Posted December 21, 2021 Author Share Posted December 21, 2021 3 hours ago, Bowie69 said: More fuel equals more hot expanded gas equals more energy to spool the turbo. Yeah of course, but your also adjusting the flow over the turbine, now I get spilling air via a bypass ( as per conventional turbo) your just sending less gas through it, vnt I guess your either slowing or speeding up the gas before it hits the turbine, just struggling to understand interaction yet. Quote Link to comment Share on other sites More sharing options...
smallfry Posted December 22, 2021 Share Posted December 22, 2021 Maybe one of these would help ? https://www.tuning-diesels.co.uk/digiboosters/ Quote Link to comment Share on other sites More sharing options...
cackshifter Posted December 22, 2021 Share Posted December 22, 2021 I think reducing fuel can limit any turbo's max boost, it can only work with the exhaust energy it has. But it is just one of the limitations. We know that the normal turbo nears its limit at a bit over 1 bar, clearly the VNTs are bigger and can go higher than that. But their advantage over the normal is ability to provide better boost over a wider range of speed; I think mine achieves that. I think you could achieve the same peak power with a wastegate turbo -the VNT is trying to increase the area under the power graph 1 Quote Link to comment Share on other sites More sharing options...
landroversforever Posted December 22, 2021 Share Posted December 22, 2021 Some of the 6BT standard applications don't have a wastegate so the boost is determined be the max fuelling. 1 Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted December 22, 2021 Share Posted December 22, 2021 5 minutes ago, landroversforever said: Some of the 6BT standard applications don't have a wastegate so the boost is determined be the max fuelling. A LOT of industrial old-school diesels don't have a wastegate at all either, 3 Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted December 23, 2021 Share Posted December 23, 2021 Mav, did your aftermarket fuel pin have a groove in it despite coming with a hardening certificate ? Mo Quote Link to comment Share on other sites More sharing options...
Maverik Posted December 23, 2021 Author Share Posted December 23, 2021 9 hours ago, Mo Murphy said: Mav, did your aftermarket fuel pin have a groove in it despite coming with a hardening certificate ? Mo Not so clear from the photo but its actually not made much of a mark at all, it's just a line that's been drawn in oily gloom, you can't feel any scoring. 1 Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted January 1, 2022 Share Posted January 1, 2022 I put a Mitsubishi VNT onto a 300Tdi more than ten years ago, and spent some time tuning it. You can eliminate the spiking in normal use by making it more sluggish to respond. I've not seen an issue from brief overboosting (since it won't be adding enough fuel to make power it's just pressurising the intercooler and arguably the cylinders, but with excess air so cooler). Aside from the gauge rattling the end stop, what's the problem you're trying to solve here? 1 Quote Link to comment Share on other sites More sharing options...
Nonimouse Posted January 4, 2022 Share Posted January 4, 2022 I have a T4 2.5Tdi Auto - so EDC pump. Great bit of kit. But all the issues with sensors and voltage that I've experienced with the 300tdi Auto. Meaning maintenance is king. I'm quite partial to the VW TDI. Mine is one of the very rare 'un messed about' lumps. Pushing out a scarey 105bhp (on the dyno, now that it's had some love). If you need pictures/a close look atthe pump - let me know 1 Quote Link to comment Share on other sites More sharing options...
Nonimouse Posted January 4, 2022 Share Posted January 4, 2022 Mav Do you have a boost ring fitted? Not the carpy one form The midlands, but the Steggy one? Quote Link to comment Share on other sites More sharing options...
Maverik Posted January 4, 2022 Author Share Posted January 4, 2022 On 1/1/2022 at 10:03 PM, Turbocharger said: I put a Mitsubishi VNT onto a 300Tdi more than ten years ago, and spent some time tuning it. You can eliminate the spiking in normal use by making it more sluggish to respond. I've not seen an issue from brief overboosting (since it won't be adding enough fuel to make power it's just pressurising the intercooler and arguably the cylinders, but with excess air so cooler). Aside from the gauge rattling the end stop, what's the problem you're trying to solve here? The problem is, on initial starting after being stopped for a little time - the engine runs poorly until the "spike" has happened, then it runs normally and in fact pretty well after I put the original fuel pin back in and tweaked it a little. Quote Link to comment Share on other sites More sharing options...
Maverik Posted January 4, 2022 Author Share Posted January 4, 2022 1 hour ago, Nonimouse said: Mav Do you have a boost ring fitted? Not the carpy one form The midlands, but the Steggy one? ok - you've got my attention - I do have a boost ring fitted... got it off ebay, not from Stegs.... The one I've got is this - Land rover defender discovery 300 / 200 tdi boost Dynamic Timing shim - Advance | eBay It came with the correct profile O rings etc. I would be surprised in any difference in quality between that and Stegs after all its just a spacer - if this is causing an issue but open to suggestions... I've got a couple of other diagnostic things I want to try, but I can't rule out that I've got something sticking on the injector pump which is totally unconnected to the VNT turbo. Quote Link to comment Share on other sites More sharing options...
Nonimouse Posted January 4, 2022 Share Posted January 4, 2022 2 hours ago, Maverik said: ok - you've got my attention - I do have a boost ring fitted... got it off ebay, not from Stegs.... The one I've got is this - Land rover defender discovery 300 / 200 tdi boost Dynamic Timing shim - Advance | eBay It came with the correct profile O rings etc. I would be surprised in any difference in quality between that and Stegs after all its just a spacer - if this is causing an issue but open to suggestions... I've got a couple of other diagnostic things I want to try, but I can't rule out that I've got something sticking on the injector pump which is totally unconnected to the VNT turbo. That's not a dealer I recognise. Nick Steggal's stuff is quality. Precision quality. Some other manufacturers don't use either of thos descriptions. Nick is a useful chap to talk to and does know a fair bit about diesel's, despite his strange love of Cummins 6BT lumps. He's on FB and is a member on here 1 Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted January 5, 2022 Share Posted January 5, 2022 7 hours ago, Nonimouse said: That's not a dealer I recognise. Nick Steggal's stuff is quality. Precision quality. Some other manufacturers don't use either of thos descriptions. Nick is a useful chap to talk to and does know a fair bit about diesel's, despite his strange love of Cummins 6BT lumps. He's on FB and is a member on here Nicks stuff is identical to everything else on the market, just 10 times the price.. 1 1 Quote Link to comment Share on other sites More sharing options...
Snagger Posted January 5, 2022 Share Posted January 5, 2022 Aren’t those rings for fuel injection timing control widening, not boost? Edit: just opened Mav’s link and that is right. For what it is, I can’t see any issue with that ring. It doesn’t need to be ultra precise or made from expensive materials. Nick’s stuff may be better quality, but this looks fine for the job. 1 Quote Link to comment Share on other sites More sharing options...
Maverik Posted January 5, 2022 Author Share Posted January 5, 2022 I see I have 2 options here, live with it, or I need more diagnostics, as I cant get my head around how this is really happening, as through normal operation I can't get the manifold pressure anywhere near where it spikes up too, which suggests its potentially over fueling allowing the engine to spin the turbo high enough for it to spike as high as it does. I installed the turbo summer 2020 which was amazingly warm... I remember first noticing this behavior early last year, can't put an exact date on it. Quote Link to comment Share on other sites More sharing options...
Nonimouse Posted January 5, 2022 Share Posted January 5, 2022 10 hours ago, vulcan bomber said: Nicks stuff is identical to everything else on the market, just 10 times the price.. No it's not - don't be silly Quote Link to comment Share on other sites More sharing options...
Nonimouse Posted January 5, 2022 Share Posted January 5, 2022 48 minutes ago, Maverik said: I see I have 2 options here, live with it, or I need more diagnostics, as I cant get my head around how this is really happening, as through normal operation I can't get the manifold pressure anywhere near where it spikes up too, which suggests its potentially over fueling allowing the engine to spin the turbo high enough for it to spike as high as it does. I installed the turbo summer 2020 which was amazingly warm... I remember first noticing this behavior early last year, can't put an exact date on it. I would live with it for the time being, whilst undertaking diagnostics. Even recording ambient temp Quote Link to comment Share on other sites More sharing options...
reb78 Posted January 5, 2022 Share Posted January 5, 2022 I know its basic but does the fact that it spikes and then performs normally suggest something is sticking when it is left at rest? 1 Quote Link to comment Share on other sites More sharing options...
Maverik Posted January 5, 2022 Author Share Posted January 5, 2022 2 minutes ago, reb78 said: I know its basic but does the fact that it spikes and then performs normally suggest something is sticking when it is left at rest? Yes! but what is sticking is the question... I've got a wee test pump just waiting for some PTF tape to arrive so I can test the actuator and boost pin independently, see if that shows any "sticking" - but from what I've tested so far I don't think its the actuator or pin. Quote Link to comment Share on other sites More sharing options...
Nonimouse Posted January 5, 2022 Share Posted January 5, 2022 5 hours ago, Snagger said: Aren’t those rings for fuel injection timing control widening, not boost? Edit: just opened Mav’s link and that is right. For what it is, I can’t see any issue with that ring. It doesn’t need to be ultra precise or made from expensive materials. Nick’s stuff may be better quality, but this looks fine for the job. It was my understanding, not necessarily correct, that they retard/advance (can't remember which) the pump timing to allow a smoother power delivery through the gears - 'no quite shutting off the pump as much' was how I had it explained. I don't have one fitted, but I've driven a few vehicles with one fitted and it's a marked difference in power delivery. I wonder if the 'sticking' is a lack of fuel at the time of demand. But that could be timing, 'on boost demand' not being right. Or alternatively I might be completely misunderstanding what Mav origionally said Quote Link to comment Share on other sites More sharing options...
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