Improving boost on an ALH with a K14

Zeitgeist

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'04 Variant and Vanagon mTDI
I just got my '89 Vanagon running with the ALH from an '01 Jetta automatic. It runs great, but isn't producing full power due to boost being limited to maybe 3 psi. The 11mm mTDI pump is from a Land Rover and the K14 turbo is from a 3.0L OM606. I fully realize that turbo is too big and it was a gamble to run with it, but this was a budget build and it's all I had on hand. My question to the crew here is to figure out if there are any ways to make sufficient boost with that turbo in place, short of radical alterations and buckets of cash. I was thinking of stepping up the nozzle size several stages, and if things get dire, I do have a 12mm pump head from a 4BT.

Thoughts?

Be kind, I'm really fragile.



 

All Stock

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I would first pressurize the intake system to make sure you don't have any leaks. Those two intake runners (3,4) having clamp bridge the two of them instead of individually looks like a leak waiting to happen, especially since it could create a buckle in the coupler. Use a PVC cap sized to fit the turbo inlet coupler, tap it for a gauge and a pressure fitting and attach it as if it were intake plumbing. Sand or scuff the outside so it holds in the coupler. See if it can hold 20 psi...or anything above 3 psi.

Also at full throttle and under load producing 3 psi are you seeing a lot of black smoke? That would indicate sufficient fuel and that the 3 psi is an issue. Even in stock form you would have a lot of black smoke without sufficient air.

That's a good place to start.
 

Zeitgeist

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'04 Variant and Vanagon mTDI
Those two intake runners have zero gap between them, so I don't think there's any air escaping there. The turbo is from an engine with only 74k on it, and the shaft spins straight and true. I don't even hear the turbine whining, nor any air escaping when the gauge shows intake boost. While there's a little oily residue inside the intake, there's none showing externally at any of the junctions. I've turned up the fuel screw about a 1/4 turn and got more power, but not much smoke.

If I were to step up the nozzle size, how far up would you folks recommend I go?
 

[486]

Top Post Dawg
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MN
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02 golf ALH
where in the rpms are you shifting?
I'd shift somewhere around 5k, if your governor spring will allow it.
If you are running stock automatic nozzles you'll likely only see 3 psi from a turbo of that size
Quick googling shows something like, from comp inducer back to turbine exducer 50mm, 71mm, 50mm, 42mm

usually I recommend as large of nozzles as you can find, but you're running mechanical governor, so if you go too large you'll run into issues with torque control
go at very least pp764, and that is still not enough flow for a 12mm pump head to survive
 
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Zeitgeist

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'04 Variant and Vanagon mTDI
I just ordered some Bosio PP764 nozzles. Will report back.


[edit] I just re-read my initial post, and thought I should clarify that I have a spare 4bt 12mm pump head, but it's not on the LR pump currently. The pump currently has the stock 11mm head.
 
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adamss24

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audi a4 2.5 tdi 98 quatrro 6speed
As mentioned above, do the intake runners totally separate if you want to hold boost ! What’s the turbine/compressor inducer/exsucer sizes ? The k14 do come in different sizes...if you don’t get fuel then you cannot make power ! Report with results although I would have gone with bosio race 520 injector nozzles and dual them back a little !
 

Zeitgeist

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Agreed about the separate runners, but that's not the problem I'm having with low boost. I'm lucky I can even get those tubes on to the runners, as they're extremely close together. I have some stainless wire coming and will try and slip that around each hose to cinch them in place.

I'm not sure about the size of the wheels, but relative to other MB diesel turbos it's really tiny, so I thought I'd have a good chance of making it work. If the nozzles don't produce boost along with turning up the pump, then I'll have to find a smaller turbo.
 

Exenos

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Is the waste gate staying shut? Even if it is a 50mm compressor which seem extremely large for a factory 3L it should be making more than 3psi at some point. More believable numbers I found quote 42mm inducer with 60mm ex with a 52mm turbine for a stock 606 turbo, which isnt all that crazy. Its big but nothing that shouldn't spool at some point . I'd wack a big spring on the waste gate to make sure its shut and see what that does first. Try the easy stuff first.
 

Zeitgeist

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I set the pre-load on the wastegate and then checked to be sure it was closed. It's tight. Somewhere I have a pic of this turbo next to a T3 which is more typical of 3.0L MBs; it's tiny
 

Sootyperry

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wastegate opening pressure

Check the opening pressure on the wastegate. On the benz the boost is controlled by the computer much like the tdi with the n75. some mercs use vacuum to control the wastegate. use a bike pump or a mityvac to check the wastegate opening pressure. you might need to run an air pressure regulator or manual boost controller to up your boost pressure or a different wastegate. Try disconnecting the wastegate hose altogether and see what it does (go easy)
 

Sootyperry

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low boost

where are you taking your boost reading from? I'm running an old a$$ k24 from a 1.6td on one of my b4v's and it is way past its efficiency range @24psi pumping lots of hot air. I got it to spool no problem with stock nozzles and a 10mm pump. R520s make it too much fun and I'm married to the gauges. I've been waiting for it to self destruct for 4 years now as an excuse to upgrade to a gt2056 wastegate I have sitting on the shelf. have you tried bumping the timing to 1.25mm and turning up the fuel screw?
 

Zeitgeist

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I converted the actuator from vacuum to pressure. I have a MityVac with pos/neg pressure capabilities. The boost reading is from the end of the intake manifold. The engine growls like a tractor, and sounds a lot like the 1.6NA engines I advanced the timing on to get more oomph back 25 years ago. The thing starts and runs great with very little smoke. It's just low on top end power. I should mention that I'm also running tires that are something like 3.5" taller than before, so I'm making the engine work harder, but none of that explains the lack of boost.
 

Sootyperry

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2x 96' b4v, 02 Jetta wagon, 95 6bta dog
what is the opening pressure of the wastegate? Is the flapper sealing inside the exhaust housing? Try turning up the fuel feed screw on the pump. larger nozzles would help for sure but I think you can make it run with the injectors you have. Disconnect the wastegate. check for exhaust leaks
 

Sootyperry

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What gov springs do you have in the pump? I see the collar is still on the fuel screw. turn up the pump you need more fuel
 

Zeitgeist

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'04 Variant and Vanagon mTDI
I have a Dawes device set to (I think) 13psi. I have no idea what the setting should be, but that's what I set it to when it was on my OM603 with a T3 turbo. The flapper valve is in place and functioning. I've already turned the fuel up 180 degrees. I was told it doesn't take much, so I've been conservatively turning it up incrementally. I get more power, but still no boost or smoke. I don't want to mess with it any further until I get the new nozzles installed. Perhaps Land Rovers are just tuned very lean, and I need to keep cranking it up for this turbo.
 

Exenos

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Have you read any ve pump tuning guides? You can go significantly more than 1/2 turn on the max fuel screw. Max the pump out first before nozzles, no harm can come as long as your careful about it.
 

Zeitgeist

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'04 Variant and Vanagon mTDI
I'm not new to VE pumps, but I am new to tuning them. All my pump tuning experience is with MB inline pumps.

The lack of smoke is a strong indication that there's not enough fuel at the moment. Is there a good source of information for how to remove the collar on the screw so that I don't bugger up the threads?
 

jimbote

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spiral arm, milky way (aka central NC)
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I don't really have much to add to the conversation but I do have a question, is this a Syncro?... I'm asking because the engine fits under the deck lid and I know the Syncro has the engine lower by almost two inches.... thanks!
 

Zeitgeist

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No this is a 2WD, and was formerly sitting at Carat height. It's now a highboy, and despite sitting under the decklid, the oilpan clearance is still in the 9.5"--10" range, which is even more than my WBX at Carat height. This is a highly unusual install that I've not seen before. I can't say yet whether I recommend this approach, but time will tell.
 

jimbote

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spiral arm, milky way (aka central NC)
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No this is a 2WD, and was formerly sitting at Carat height. It's now a highboy, and despite sitting under the decklid, the oilpan clearance is still in the 9.5"--10" range, which is even more than my WBX at Carat height. This is a highly unusual install that I've not seen before. I can't say yet whether I recommend this approach, but time will tell.
so the engine and trans is not lowered from stock ? ... about to convert a syncro to alh and want to use the south american 15 degree bell for simplicity
 

Zeitgeist

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Yes, the drivetrain is essentially lowered to Syncro height. I used a Passat 1.8t oilpan and the stock (well, extended from the frame) WBX crossbar underneath the pan. I don't think the stock ALH intake would fit under the lid, which is why I made my own.
 

jimbote

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spiral arm, milky way (aka central NC)
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Yes, the drivetrain is essentially lowered to Syncro height. I used a Passat 1.8t oilpan and the stock (well, extended from the frame) WBX crossbar underneath the pan. I don't think the stock ALH intake would fit under the lid, which is why I made my own.
ok, cool ...you are correct, stock alh intake would interfere with the deck lid
 

Zeitgeist

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Ok, to follow up on this thread, I thought I'd provide an update. It turns out that the wastegate actuator was opening way too soon, which was dumping boost before it had a chance to develop. I disconnected the actuator boost signal and have been running without a wastegate for a while now. It would develop about 10-12lbs of boost with the old nozzles, but now with the PP764s I just installed, it produces around 15-17lbs...and it's a freakin' rocketship now! I still need to figure out a wastegate that functions properly, but I'm very happy with the results to date. Too bad it took the vendor five months to deliver my nozzles...grrrrrrr

So, to sum it up; a K14 is perfectly fine as a turbo on an ALH so long as the wastegate functions and you have the properly sized nozzles to take advantage of its abilities. Color me very pleased with this swap.


[edit] oh, and the cardboard snorkel in the pillar also collapsed, which was further reducing my boost. Teething issues with the swap.
 
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