Turbo boost log from my new VNT17

mrfiat

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On a 2003 ALH wagon. This is my first boost log from my new VNT17. How does it look? I am running a 11 mm pump and 1019 injectors.

http://log.malonetuning.com/chart/2...Cj8OgYMOsIcOuJnXDi2zDjcKPUwgnwrc8w6Ynwo8AAAA=

The VNT15 got up to requested boost faster. Is it normal for the VNT17 to lag some? It doesn't reach requested until 3400 rpm. The VNT17 actuator was set correctly (I hope) from the factory.

On another note, my injector pump solenoid died right after this run for some reason and left me stranded. I had to Uber home and get the solenoid off my other car. The solenoid was new.

Thanks!
 

Mike_04GolfTDI

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It does look like there's quite a bit of lag. If you don't have a tune I would say that's probably normal due to the larger turbo.

A tune would probably liven things up a bit.
 

mrfiat

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Thanks. Has anyone on here done a boost log from their ALH with a VNT17 that they can share? (This way I can compare the two)
 

mrfiat

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I shortened the actuator arm on the VNT17 twice. The requested vs. actual boost got a little better the first time I shortened it and got worse the 2nd time. I will put it back to where I had it the 2nd time. I guess a VNT17 will not meet requested boost right away like a VNT15.
 

mrfiat

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I decided to try swapping out the N75 valve with a used one I had on the shelf. The boost log looks much better. :) I thought N75 valves either work or they don't, but maybe there is more to it.

http://log.malonetuning.com/chart/240668#H8KLCADCuhfDjVsCA03Ci8ORCsKDMAwAw78lw48Nw6jDsG9KH8OqDDXDkDXCksOGw6HDtsO1w5oKY8KPd8OHeQ9PecONXAjCk8OKwr5VcENwTWZRw77DksKFDhIVw5JoBHcpb1JDEzwwHsOcwo7Du8KJw4vCgsKfwp8Cw6XCtFpfKsOZX8Owwo%2FDoGDDrCHDriZ1w4tsw43Cj1MIJ8K3PMOmJ8KPAAAA

I might try making the actuator a little longer to get rid if the small amount of overboost that I am getting.
 
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PakProtector

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I seem to remember that by 22-2300 my VNT17 was making requested. This on an otherwise stock ALH. IIRC it was requesting full boost by 2k rpm. The VNT bit got set with a vac pump as detailed here; little bit of movement at 3 and closed by 18...:)

Douglas
 

Vince Waldon

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If you don't have a tune I would say that's probably normal due to the larger turbo.
Yup, if the only thing you've changed is the turbo it's gonna be laggy... the ECU still thinks it's fueling the old (aka smaller) turbo.

A VNT-17 is upgraded hardware, and as such is at it's best when the software is upgraded to match. :)

If you've already installed a tune and it's laggy then your tuner is probably the best person to start the troubleshooting process with.
 

mrfiat

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Some of the lag did go away with the replacement N75 valve. I will get a tune when finances permit. Thanks!
 

eddieleephd

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Some of the lag did go away with the replacement N75 valve. I will get a tune when finances permit. Thanks!
I decided to try swapping out the N75 valve with a used one I had on the shelf. The boost log looks much better. :) I thought N75 valves either work or they don't, but maybe there is more to it.

http://log.malonetuning.com/chart/2...wwo/DoGDDrCHDriZ1w4tsw43Cj1MIJ8K3PMOmJ8KPAAAA

I might try making the actuator a little longer to get rid if the small amount of overboost that I am getting.
I run a VNT17, don't adjust the overboost out! You actually want to go the opposite direction and adjust it to be about 100mbar over at peak boost and it will be perfect for the spooling.
I am seeing 120mbar overboost the way mine is set. I do have a tune and am pushing 23 requested and the 138 over maximum is 2psi 25psi.
In your situation, without tune, is only 21psi total and way less than the VNT17 is capable of doing, which is 26-28 psi boost regularly.

If you lower your IQ, possibly hammer mod, the injected quantity will increase and spooling will occur quicker. The adjustment to the actuator I mentioned will help the actual to be closer to the requested.

The vnt15 is known to spool at lower rpm like a natural aspiration short ram intake, the VNT17 is going to spool a few hundred rpm higher similar to a medium ram intake, and a larger turbo probably the 17/22 is closer to a long ram intake.
Do some research and discuss with the tuner you prefer about supporting mods before you get to ahead of yourself.

Sent from my Armor_2 using Tapatalk
 

Nevada_TDI

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There are some here that have swapped out their 2.5 bar MAP sensor for a 3 bar MAP sensor after installing a bigger turbo, but before getting a tune. It might throw an error code causing limp mode and maybe it will not. At some point you will likely want a 3 bar MAP sensor to take advantage of the bigger turbo. You might get a bit better spool after lowering your IQ as well, but that is another subject.
 

mrfiat

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Thanks guys. I do plan to get a 3 bar MAP sensor when I do get the tune. The IQ is set to 4.2 right now. I will try lowering the IQ to 3.0 and see what it does to the boost log. (and go in a turn or two on the actuator)
 
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eddieleephd

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Here's a log of mine the way it's set now, remember, I have a Malone stage 4 tune with unknown nozzles. As I said I try to get it between 100-138 over on spike usually. I'm getting ready for an exhaust and do not want to turn it up until after that, and I am waiting on injectors which will likely result in another adjustment to get it to spool a bit closer yet. Presently my IQ is set to around 3 and I see no smoke when driving.
You should be able to get the spooling up to near what the VNT15 was doing, however, not so quick. The physical timing, although difficult to set, has quite a bit to do with it as well so take your time and see what might help. Different people find different timing desired, timing for spool is different than timing for efficiency and both will be affected with an adjustment.

The first rise is 3rd and second rise is 4th
http://log.malonetuning.com/chart/2...Cj8OgYMOsIcOuJnXDi2zDjcKPUwgnwrc8w6Ynwo8AAAA=
3rd-5th

http://log.malonetuning.com/chart/2...wwo/DoGDDrCHDriZ1w4tsw43Cj1MIJ8K3PMOmJ8KPAAAA
3rd gear run I was adjusting down from

http://log.malonetuning.com/chart/2...wwo/DoGDDrCHDriZ1w4tsw43Cj1MIJ8K3PMOmJ8KPAAAA
 

mrfiat

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My timing is set one block below the green line right where I want it. I have been adjusting it and I think this is the best I can get. It is not meeting requested boost until 2500 rpm and peaks almost 100 mbar above requested.

Here is the latest boost log:

https://log.malonetuning.com/chart/...Cj8OgYMOsIcOuJnXDi2zDjcKPUwgnwrc8w6Ynwo8AAAA=

Eddie, it looks like your VNT17 is meeting requested from 2200-2500, so I think 2500 should be ok.
If anyone thinks I should shorten the actuator rod more, please let me know?
 

eddieleephd

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That last one definitely looks better, with the 1019 injectors it seems like you can push it a little bit further and get it spooling a little sooner.
I would play with the IQ, of course the IQ can be something of a trade-off, Maybe hammer mod to get a bit better response.
Where is your IQ now? Have you hammered it before?
 

mrfiat

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The IQ is 4.4. I don't think there is any need for the hammer mod since I am trying for around an IQ of 4.0.

Do you think I should lower the IQ? I don't need the hammer mod to do that. Do you think I should shorten the rod even more? It is already overboosting about 100 mbat above requested. If I shorten it then it will overboost even more. I just don't want to get that big dip as the ECU tries to lower the boost.
 

eddieleephd

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The IQ is 4.4. I don't think there is any need for the hammer mod since I am trying for around an IQ of 4.0.

Do you think I should lower the IQ? I don't need the hammer mod to do that. Do you think I should shorten the rod even more? It is already overboosting about 100 mbat above requested. If I shorten it then it will overboost even more. I just don't want to get that big dip as the ECU tries to lower the boost.
A lower IQ will inject more fuel causing the turbo to spool faster, however, you know what it can do to fuel mileage.
138-200 mbar is acceptable especially with the vnt 17. You can easily adjust to seeing 4lbs over without hurting the turbo. This would help spool the turbo by increasing actuation angle more.

The other option I have seen around here is installing a 3bar MAP sensor, which if you are going to get a tune this may be a good option. Just don't like recommending one without an aftermarket boost gauge.


I would do a bit more research into the options and then choose.
In the end a slight adjustment in IQ and 3bar MAP sensor is likely to be the easiest midterm option. This way you don't increase the fuel as much and the ECM will ask, unknowingly, for more boost.


I think it's imperative to have a gauge ensuring that you don't go past the expected differences without knowing.


Even at a 120% increase in boost due to the MAP change 18lbs*1.2=21.6 and another for the over-boost of 3lbs*1.2=3.6 and the grand total of 25.2lbs, which is 2.8lbs below the recommended 28psi maximum.


The ECM may find the difference to the MAF expected to be arguable and throw a code for that under heavy acceleration at that point, however, safe operation with external gauge verification.
 

mrfiat

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I ordered a Malone stage 4 tune and a 3 bar MAP sensor today. Once I install that, then I will run the boost logs again and see how it looks. If it doesn't boost fast enough then I will try lowering the IQ and see what that does.


Do I have to have a boost gauge? The tune should make sure that I do not exceed the max for the VNT17, right? (limp mode if I'm going above it)
 

eddieleephd

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I ordered a Malone stage 4 tune and a 3 bar MAP sensor today. Once I install that, then I will run the boost logs again and see how it looks. If it doesn't boost fast enough then I will try lowering the IQ and see what that does.


Do I have to have a boost gauge? The tune should make sure that I do not exceed the max for the VNT17, right? (limp mode if I'm going above it)
Reset everything to default before you install the tune, including IQ. After the tune is installed you will likely want IQ between 3 and 4.

Everything will change with the tune, requiring adjustment, and it will definitely spool faster.
It's going to be requesting a lot more boost as well.
 

Owain@malonetuning

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Limp mode and limiters can only do so much, you could be regularly spiking and not know, limp mode is typically caused by sustained over boost but you could have rapid short spurts of overboost and spikes that won't trip codes. Newer ECUs are more sensitive for that but the ECU in these ALHs isn't all too smart.

It's always best to do a data log every once in awhile, just like an annual check up. Won't really know if anything is out of spec until symptoms arise, and hopefully it's nothing major when they do, catching it early is always best.
 
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