Maybe try temporarily disconecting the wastegate to rule it out?
The 2H/12H-T/1HZ/1HD-T/1HD-FT Gturbo Alternative Tech Thread (1 Viewer)
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mudgudgeon
Resident galah
Have you bench tested the waste gate actuator?
Is there any other symptoms? Puff of smoke out the back, stumbling?
Is there any other symptoms? Puff of smoke out the back, stumbling?
mudgudgeon
Resident galah
Did you change anything with the fuel system? Have any of it apart?
I'm thinking either fuel starvation/ air in the fuel, waste gate malfunction, some form of blockage in the intake.
I think you'd hear a boost leak.
Air in the fuel will cause a stumble and white smoke out the back.
Air intake blockage will choke the engine, and also cause momentary puff of smoke out the back
Waste gate malfunction is probably less obvious.
I'm thinking either fuel starvation/ air in the fuel, waste gate malfunction, some form of blockage in the intake.
I think you'd hear a boost leak.
Air in the fuel will cause a stumble and white smoke out the back.
Air intake blockage will choke the engine, and also cause momentary puff of smoke out the back
Waste gate malfunction is probably less obvious.
serenity
SILVER Star
I haven't changed the fuel settings since swapping in this turbo, just suddenly started acting up a few hundred km ago. No obvious black smoke, stumbling, massive loss of power or anything. I replaced my fuel lines, injectors and primer pump earlier this year. Drove fine with this turbo for the first 400km then it started misbehaving.
I'll pull the actuator off and test it later this week. Got an exploded transfer case to deal with also.
That's a strange one. Fuel starvation fits the symptoms in my eyes, pulls hard till it runs out of fuel, power drops, boost drops. I'd start looking into that.
When was the fuel filter last changed? The only other thing I can think of is the in-tank setup needing some TLC...
When was the fuel filter last changed? The only other thing I can think of is the in-tank setup needing some TLC...
This would be my suggestion as well. If your truck is down for the transfer case then I guess you can't really to this, but if it was running I'd disconnect the wastegate and let it free boost and see if it builds more pressure without issue.
Dynoed the gturbo for a baseline to compare the prototype to. Have lost ~40rwhp from the last dyno with the Garrett. This is probably due to a number of factors, completely different climate and atmospheric conditions, different brand of dyno etc etc. Not reading into it too much, as it's not a comparison between them, it's between the gturbo and the prototype. Anyway, made 205-215rwhp, ambient temp was 35, pre turbo egt 700-750C, Afrs 19-20:1 through midrange and full throttle. Pre spool is soot central, 12-13:1 
Intake temps 58-60C, 35psi. I ran it at 39psi, 18:1, all it did was make things very hot, very fast 
Actually started making more power once I removed fuel, pulled so much fuel out I had to increase the idle 
suspect the turbo was being choked by excessive fuelling. Lost a bit of midrange due to the reduced fuel, but with a bit of compensator tweaking managed to get it back 
so drivability is unaffected. Will swap the prototype on next weekend and go back on the rollers early in the new year 
Intake temps 58-60C, 35psi. I ran it at 39psi, 18:1, all it did was make things very hot, very fast Actually started making more power once I removed fuel, pulled so much fuel out I had to increase the idle suspect the turbo was being choked by excessive fuelling. Lost a bit of midrange due to the reduced fuel, but with a bit of compensator tweaking managed to get it back so drivability is unaffected. Will swap the prototype on next weekend and go back on the rollers early in the new year
mudgudgeon
Resident galah
so those numbers are G-turbo?
yes
What was drive pressure doing on spool up, just as the wastegate cracks?
Nice bar by the way
Nice bar by the way
What do you mean?
Cheers, I got sick of being stuffed around by AOE so I redesigned it slightly and got it built on the Gold Coast
Tapage
Club 4X4 Panamá
previous run was at how much boost PSI ..?
Did you try at 39 - 40 PSI range with less fuel .:?
Did you try at 39 - 40 PSI range with less fuel .:?
U mentioned that going from 35psi @ 19-20:1- 39psi @18:1 things got very hot very quick . 1 afr point isn't a drastic change, not enough to cause a massive temp difference . Did the boost rise to 39psi with extra fuel or did u have to adjust the waste gate . If the boost increase was with a wastegate adjustment then I would be looking to drive pressure to be the issue . The turbine might choking because the wastegate isn't opening enough plus the heavy fuel load . Drive pressure is the ratio of boost to exhaust manifold pressure. Could be compressor efficency and intercooler efficency as well .
Be somthing to monitor with your prototype too .
Yes, I backed the fuel off before reducing boost, it made no difference to power, just decreased spool up performance
I don't think it's as simple as 1 afr point, it's more to do with the drastic reduction in fuel required to decrease the boost and afr. Simply reducing the fuel resulted in similar boost with a leaner afr, and markedly increased the time taken to spool, because of the reduced drive energy. When I originally tweaked the pump, a while back, it was just a fuelling increase that changed the boost from about 33psi to 39psi, no boost adjustment was made. This time, I adjusted both, first the fuel, to reduce the black smoke and heat, and then knocked 5% duty cycle off the boost controller, which resulted in 35psi, but still with the lost bottom end and midrange performance. Had a play with the compensator, and got that back. Peak egts came right down after the fuelling reduction, and climbed much slower, even after the compensator tweaking. I do suspect the turbine was choked from the heavy fuel load, resulting in performance loss and excessive heat. Haha I'd be more inclined to blame the compressor over the intercooler
but when I run the prototype, that will be clarified, as it's compressor wheel design is significantly different to the gturbo. There is a setting on the boost controller called gain, which reduces the rate at which the wastegate opens, allowing more drive pressure to spool the turbo before the gate cracks, I'll have a play with that after I've done the initial comparison runs with no adjustment to anything
AussieHJCruza
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What boost controller are you running?
Gfb g-force 2 electronic
Definitely reducing fuel (heat, drive energy)will do exactly that but you are seeing similar power with both high and low fuel loads which is why I ask about drive pressure . If drive pressure and inlet temps are good and your pump can maintain timing at high rpm 1 afr point makes 30-40 degrees difference to egt's ( nothing drastic)
Knowing that u got the boost increase with more fuel only and no boost controller adjustment but with little power increase points to the turbine choking(high emp, high drive pressure) counter productive to power . Each turbine housing and turbine has its own sweet spot for efficency. usually with a drive pressure ratio below 1.5:1 the closer to 1:1 the better. It's a handy thing to measure and u don't have to guess when u have all the data . And with some fine tuning, the boost controller you have will allow slightly higher drive pressure on spool up (earlier, faster spool) but then allow the the gate to progressive open more to control emp and help make power efficiently .
I'm not knocking what you've done, just trying to confirm if the turbine and wastegate was actually choking or just the turbine with gate closed to much. Initially I though you may have adjusted the boost controller holding the gate shut to much which made it seem like the turbine was choking. I like big power and if I see someone unsure why their adjustment didn't yield the gains expected I'll try to help .
Thing are easier with all the data . Tap your exhaust manifold and measure emp, you might get a shock . It will also help setting and fine tuning your boost controller .
Looking foward to seeing your prototype's results !
Knowing that u got the boost increase with more fuel only and no boost controller adjustment but with little power increase points to the turbine choking(high emp, high drive pressure) counter productive to power . Each turbine housing and turbine has its own sweet spot for efficency. usually with a drive pressure ratio below 1.5:1 the closer to 1:1 the better. It's a handy thing to measure and u don't have to guess when u have all the data . And with some fine tuning, the boost controller you have will allow slightly higher drive pressure on spool up (earlier, faster spool) but then allow the the gate to progressive open more to control emp and help make power efficiently .
I'm not knocking what you've done, just trying to confirm if the turbine and wastegate was actually choking or just the turbine with gate closed to much. Initially I though you may have adjusted the boost controller holding the gate shut to much which made it seem like the turbine was choking. I like big power and if I see someone unsure why their adjustment didn't yield the gains expected I'll try to help .
Thing are easier with all the data . Tap your exhaust manifold and measure emp, you might get a shock . It will also help setting and fine tuning your boost controller .
Looking foward to seeing your prototype's results !
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Turbines don't actually choke, technically they run in choke flow and just require more and more drive pressure the more work you want from them.
If a turbine is suddenly spiking in drive pressure, then it's likely because the compressor side load just spiked. Which can happen when the compressor reaches the edge of it's map.
If a turbine is suddenly spiking in drive pressure, then it's likely because the compressor side load just spiked. Which can happen when the compressor reaches the edge of it's map.
Very True Dougal , saying the turbine has choked is usually easier for people to understand than to get into all the fine details. It's all about efficency . The badboy turbo of Graeme's has been used successfully at 40+psi, this led me to think it was a waste gate flow issue.
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