14BT Turbo Upgrade: Munro GMT upgraded billet (1 Viewer)

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Nice. Is that an ammo-can air box?
Yeah mate... Made it up a while ago.

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Which turbine housing number does the old one have?
 
So, I've had a bit of an issue for a while with my engine surging in 3rd and 4th under load intermittently and I need to fix it before I can compare the old turbo and new one effectively. I suspected a slipping clutch at first, but it seemed to improve at times when I switched between my two tanks. Also, one tank felt down on power than the other... That made me think it must be fuel related and I thought it might be fuel starvation. I changed the fuel filters last week and it felt a bit better, but it's still been there intermittently. Anyway... A few extra things on the new install.

1) I put the old boost tee on the new turbo today and it was immediately boosting to 23psi, whereas the old turbo only reached 15 with the same boost tee - any ideas why that would happen? - more efficient turbo?

2) I put a T joiner into the boost compensator line and ran my second boost gauge there for the first time (post intercooler) and I've noticed that I've got a pretty significant drop of pressure across the little front mount intercooler. At WOT this afternoon I was getting 17psi at the cross over pipe (pre intercooler), but only 10psi just before the intake manifold (post intercooler) and the boost is fluctuating post intercooler. It seems to fluctuate when it starts surging, but before this it builds in line with the pre intercooler boost gauge.

3) It mostly surges when under heavy load / acceleration. If I accelerate more conservatively, it doesn't seem to do it as much. I need to do more testing to isolate the specific symptoms.

Also, to be clear, I don't think this issue is in anyway related to the new turbo... I suspect having more air flow is exacerbating the underlying issue, but it's not sure to the turbo. It's something that started about one month ago, but I need to resolve it before I can compare the two turbos.

Any ideas? I'm thinking a boost leak possibly?
 
So, I've had a bit of an issue for a while with my engine surging in 3rd and 4th under load intermittently and I need to fix it before I can compare the old turbo and new one effectively. I suspected a slipping clutch at first, but it seemed to improve at times when I switched between my two tanks. Also, one tank felt down on power than the other... That made me think it must be fuel related and I thought it might be fuel starvation. I changed the fuel filters last week and it felt a bit better, but it's still been there intermittently. Anyway... A few extra things on the new install.

1) I put the old boost tee on the new turbo today and it was immediately boosting to 23psi, whereas the old turbo only reached 15 with the same boost tee - any ideas why that would happen? - more efficient turbo?

2) I put a T joiner into the boost compensator line and ran my second boost gauge there for the first time (post intercooler) and I've noticed that I've got a pretty significant drop of pressure across the little front mount intercooler. At WOT this afternoon I was getting 17psi at the cross over pipe (pre intercooler), but only 10psi just before the intake manifold (post intercooler) and the boost is fluctuating post intercooler. It seems to fluctuate when it starts surging, but before this it builds in line with the pre intercooler boost gauge.

3) It mostly surges when under heavy load / acceleration. If I accelerate more conservatively, it doesn't seem to do it as much. I need to do more testing to isolate the specific symptoms.

Also, to be clear, I don't think this issue is in anyway related to the new turbo... I suspect having more air flow is exacerbating the underlying issue, but it's not sure to the turbo. It's something that started about one month ago, but I need to resolve it before I can compare the two turbos.

Any ideas? I'm thinking a boost leak possibly?

Difference in boost, unless your old turbo is cooked, is likely due to different wastegate springs.

Sounds like compressor surge caused by that big pressure drop across your intercooler. 7psi is huge! It's causing the turbo to run at higher pressure but lower flow. If you're going to surge then that combo will do it.

Find the flow problem with the intercooler/piping or fit a bigger one and you should be sweet. With 7psi drop your engine will get more air and be happier with no intercooler. So feel free to bypass it for a test. Could also be a delaminated hose or something wierd like that.
 
Difference in boost, unless your old turbo is cooked, is likely due to different wastegate springs
I have a feeling that the old turbo might have been cooked... The new turbo has the wastegate set at 14psi, but when I took the boost tee from the old turbo and put it on the new one it was immediately boosting to 23psi. I would have thought that it should have boosted the same as the old one.
 
Find the flow problem with the intercooler or fit a bigger one and you should be sweet. With 7psi drop your engine will get more air and be happier with no intercooler. So feel free to bypass it for a test
Yeah, my first thought this arvo was to try and bypass the intercooler, so I got one of those horrible flexible connectors, but it was too hard to connect it up. I'll go to a performance parts place on Monday and see if they have anything to bypass it. It's a different setup with the intercooler as the inlet and outlet are on the same side... It's approximately 550 X 160 X 70.

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Okay, well I've discovered that my cheap same side inlet/outlet intercooler is seriously restrictive. I bypassed it this afternoon and the difference in boost building is incredible... Without the intercooler boost comes on hard and fast.

However, I still have the same issue. I think I have a fuel starvation issue, but I'm struggling to isolate it. I've replaced all the filters and tried checking the gauze under the banjo bolt (previous pump builder must have left it out because it wasn't there) but it's still surging under load. I think having more boost is exacerbating the issue because it seems more pronounced. If I accelerate conservatively it drives without surging, but as soon as I give it a bit of right boot it starts surging.

I'll try and run a tank of diesel from a separate Jerry can and different fuel line to try and isolate it to the pump and then go from there.
🤞

But the new turbo is freaking awesome... 🤙
 
I haven't had a chance to grab some fuel hose to run the pump from a separate tank, but I'm almost certain my issue has something to do with my Pollak six valve switch. Driving home from work today Frank almost cut out twice as if he was running out of fuel (filled up a few days ago so I know 100% there is fuel - I even undid the tank bung when I got home to check and see if there was any contaminants - none). However, when I switched tanks, the issue disappeared... Driving normally. Switched back to double check and sure enough he almost immediately wants to stall, so I switched back and got home.

When I got home I switched the aux and main tank ports on the Pollak and suddenly there's no feeling of stalling... Still not sure what could go wrong with the valve, but I'll double check by bypassing it on the weekend to see how it goes. Any advice regarding the Pollak?
 
Yeah that intercooler is a weird one. Long flow path but really restrictive. The same size/shape as a single pass would be the smallest you'd want to run and would give about 1/4 of the flow restriction.

Good to hear you've found the problem.
 
Any advice regarding the Pollak?
Not so much the Pollak but fuel switches in general. A 75 series owner was having problems similar to you with one tank giving him problems. It turned out to be some some orange plastic, similar to emergency tape I think, inside the factory solenoid valve partially blocking the fuel flow.
Instead of pulling it all apart, maybe you could swap fuel lines to see if the problem is still there with that tank.
 
Yeah that intercooler is a weird one. Long flow path but really restrictive. The same size/shape as a single pass would be the smallest you'd want to run and would give about 1/4 of the flow restriction.

Good to hear you've found the problem.
Yeah, I'm thinking of going a single pass in either the same size 550x140, slightly larger at 550x180 or even 550x230... The 180 would be fairly easy to fit, but the 230 would take a bit more work. Would it be worth it for the 230 or do you think the 180 would be good enough?
 
Not so much the Pollak but fuel switches in general. A 75 series owner was having problems similar to you with one tank giving him problems. It turned out to be some some orange plastic, similar to emergency tape I think, inside the factory solenoid valve partially blocking the fuel flow.
Instead of pulling it all apart, maybe you could swap fuel lines to see if the problem is still there with that tank.
I actually did that this week Rosco. Driving home from work over afternoon it started stalling a couple of times like it was running out of fuel, so I switched tanks and it came good. I even tried switching back, but it almost immediately stalled again. Definitely had diesel, so I switched the inlet and return lines on the Pollak valve to each of the tanks that night and it came good again (actually, both tanks did). Since then, I've had an intermittent fuel starvation issue. Sometimes it's bloody brilliant and pulls really hard and then other times it's doing the same surging, especially in 3rd and 4th... If I switch tanks it seems to help sometimes. My next step is to run a new fuel line from a Jerry can straight to the IP just to confirm that the issue is pre pump. Apart from the fuel issue, the new turbo is awesome. 👌
 
Are you running the 75 series dual tanks in the HJ75 chassis?
 
Are you running the 75 series dual tanks in the HJ75 chassis?
Not quite... I've got a factory rear tank that sits between the chassis (holds approximately 70ish liters) and an internal 40 series one that runs across the cab under the seats and holds approximately 90ish liters.
 
Also, any opinions on the following intercooler internals... Both 550x180x50 straight through and basically the same price.

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Or this one, which is 550x180x65 (so slightly thicker) and the following bar and plate core:

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I'd go for the middle Autoray one. Cores are less likely to leak and better flow across it (to your radiator) than bar/plate.

Top one looks like better air to the radiator than bar/plate also but not as robust inside as the middle.
 
So... I tried bypassing the tanks today with a fuel line directly from a Jerry can to the injector pump, but the same issue was there, which I think means I've got an issue internally in the pump. 😒

I had the pump rebuilt by a local shop a couple of years ago, but I also had the injectors 'rebuilt', only to find out about a year later that they had only been cleaned (they charged me rebuild rates mind you). Being a relatively rare engine in Australia is perhaps part of the problem, but I just think some people are arseholes who take your money and don't give a s***.

I got my injectors rebuilt by Josh at JH Hilux last year and he actually sourced the right parts from overseas, shipped them to Aus and then rebuilt them. I think I'll drop in and say g'day to him and see what he thinks about the pump. Argghh... Anyway - that's life.
 
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