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Go Back   TDIClub Forums > VW TDI Discussion Areas > TDI Power Enhancements

TDI Power Enhancements Discussions about increasing the power of your TDI engine. i.e. chips, injectors, powerboxes, clutches, etc. Handling, suspensions, wheels, type discussion should be put into the "Upgrades (non TDI Engine related)" forum. Non TDI vehicle related postings will be moved or removed. Please note the Performance Disclaimer.

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Old April 27th, 2004, 07:10   #1
Peter Cheuk
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Default VNT turbo in an A3/B4?

I was wondering if anyone with a 1Z or AHU engine has converted their car to a GT-VNT15 or GT-VNT17 turbo?

Any thoughts on doing this? I know that the wastegate actuator does not work well to try to modulate the boost on a VNT turbo but is there a way to get this to work without doing anything major to the engine (new ECU, etc)?

TIA.
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Old April 27th, 2004, 07:38   #2
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Default VNT turbo in an A3/B4?

Jeff at Rocketchips suggests that from an ECU programming point of view, it can be done. What is less clear is the actual hardwiring of the N75 and other control stuff to deal with the vacuum-actuated VNT mechanism versus the pressure-actuated wastegate.

I'm interested in finding more about this as well.
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Old April 27th, 2004, 08:45   #3
mojogoes
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Default VNT turbo in an A3/B4?

Peter, diesel des has done this with very good success give him an e-mail (desauld@hotmail.com) [img]/images/graemlins/rolleyes.gif[/img]
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Old April 27th, 2004, 11:04   #4
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Default VNT turbo in an A3/B4?

Hi Peter,

Glad you asked, this has been a side project of mine for the past year. This is the 68 pin euro AFN110 (immo1). I have this conversion for either wastegated or vnt versions. It also comes in a version that runs the A4 maf - very snappy response for an A3.

I have several folks testing this now, and will release it soon. btw, this is big injector firmware with 18.5 psi boost, using a boostvalve with the N75 for smooth wot power.

I can also say the bad news is every car I've tested this in, the clutch slipped :-) I just installed a new engine and vr6 clutch in my friends 96 passat last night and will test some more tonight.

The 68 pin AFN110 using the vnt15 and A4 maf with .205 injectors will be a very powerful upgrade. Other good news is there are automatic maps too, if you want to be the 1st automatic 96 passat. You can also load 4 separate tunings as well (ie, oem, stage 1, 2, and 3) However, you can't mix 1Z/AHU and AFN tunings - different firmware.

I'll probably add a webpage to my site in the next few weeks, I'll keep you posted.

I'll convert a wastegated A3 to vnt15 soon and have the necessary parts list and exhaust plate/adaptor for this too. FMIC will follow . . .

Regards,
Jeff
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Old April 27th, 2004, 19:37   #5
Peter Cheuk
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Default VNT turbo in an A3/B4?

Jeff, that sounds intriguing. At a recent Dyno Day here in the SFBA, it was proven, again, that the earlier non-VNT cars don't make as much HP because of the standard turbo. That's why I made this thread.

Something you posted that sounds interesting: one chip with multiple programs, can these programs be changed "on the fly"? I'd love to have stock and Stage III at the minimum.
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Old April 27th, 2004, 21:31   #6
jsrmonster
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Default VNT turbo in an A3/B4?

Hi,

All 68 pin A3/B4 ecu's can be made with dual maps and hard switch that you can switch on the fly. I can do this, just pm me for more details.

Jeff
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Old April 28th, 2004, 00:30   #7
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Default VNT turbo in an A3/B4?

I've done similar conversion in my by-passed AGR engine.

It required exchanging whole charge pressure regulation system and ECU re-programming. In case of 1Z engine exchanging ECU may be needed (perhaps AFN ECU).

Here is the link to my post describing whole procedure:
GT15 -> VNT15 conversion

After converting to VNT15, conversion to VNT17 is very simple - you just have to put an adapter on outlet pipe.
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Old April 28th, 2004, 07:05   #8
Peter Cheuk
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Default VNT turbo in an A3/B4?

[ QUOTE ]
I can also say the bad news is every car I've tested this in, the clutch slipped [img]/images/graemlins/smile.gif[/img] I just installed a new engine and vr6 clutch in my friends 96 passat last night and will test some more tonight.

[/ QUOTE ] I have a Sachs Power Clutch waiting to be installed so I think I have that covered.

How did the testing on the B4 go?
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Old April 28th, 2004, 08:03   #9
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Default VNT turbo in an A3/B4?

While I'm not the addressed, I have had a Sachs Power Clutch in my B4 since last summer, and I can say that for my setup, I have never had any slip whatsoever. Pedal feel, effort and modulation have not changed perceptibly.
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Old April 28th, 2004, 08:25   #10
VWannabe
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Default VNT turbo in an A3/B4?

I am glad to see this is getting revisited. The 110 HP A3 TDIs were supposed to have the VNT turbos, which helped with the HP and torque. I am curious about the program to run the A4 MAF. Is the design different which allows more power to be made? The A4 MAF is much more unreliable than the A3 MAF, so unless some startlingly results were shown for this combo, I don't think I would even consider this. I would also like to see some dyno runs of the A3/B4 cars that have had the VNT turbo installed. This would be cool if it substantially raised power and gave better driveability.
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Old April 28th, 2004, 10:28   #11
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Default VNT turbo in an A3/B4?

Hi,

I'm considering a K04-001 turbo using an adapter plate to mate it to the exhaust manifold. It has been suggested that the K04, mated to a ceramicoated exhaust manifold, will flow more air at 19-psi than my GT15 and reduce IATs... netting a gain of about 15-20 hp. I'm always skeptical. But my stock turbo can't last forever. [img]/images/graemlins/wink.gif[/img] I'd rather replace it BEFORE pieces of it wind up inside the engine. [img]/images/graemlins/laugh.gif[/img]

What do you think of the power potential of these upgrades?

Comments?

Scott
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Old April 28th, 2004, 10:50   #12
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Default VNT turbo in an A3/B4?

As has been posted many times, in and of itself, a turbo swap with a bigger unit and running more boost will result in a negligable increase in HP in a Diesel if it's not accompanied by an increase in fuelling. So, I'm left questioning the claims from your source of a 15-20 HP gain from a turbo change alone, but I would say, "no."

Neglecting the effects of the intercooler, a reduction of IAT at a constant boost pressure can only occur if there is an increase in the compressor efficiency at that particular operating point. While this is not clear-cut, I do recall seeing a map of a K03 and it seems to be near it's airflow limits at 19 PSI boost and redline on a TDI, with efficiency only in the 60-65% range. A larger, higher flow turbo will certainly be more efficient in this area (near redline), but the location of the efficiency island is not affected significantly and the peak efficiency also doesn't change much (between 72-74%). I assume most of your time is not spent at max load and redline, so the real-world benefits of a bigger turbo will not be frequently noticeable.

Also bear in mind that the K04 would be from a gasser application, and that means a number of things: trims and A/R ratios that are optimized for higher flow / lower boost, and higher energy exhaust (higher EGT in a gasser). Therefore the A/R will tend to be a higher number, which is good to make more top-end power, but more laggy on the bottom-end.

Also, unless you're getting a hybrid turbo, the centre section of the K04, like most gasser turbos, would be water-cooled, which means necessitating plumbing a coolant supply- and return line.
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Old April 28th, 2004, 10:58   #13
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Default VNT turbo in an A3/B4?

One other thing: a coated exhaust will do NOTHING directly for IAT, nor for airflow on the compressor side. That's logical.

Where it will help is in reducing the heat rejection from the manifold, and that has a number of benefits, including lower underhood temps. A higher turbine inlet temp will help spool-up (although the magnitude of the gain nobody really knows). A higher initial temperature at the turbine inlet and greater temperature delta across the turbine means increased efficiency (thermodynamics 101), and that directly affects manifold backpressure (increased total efficiency = reduced backpressure) but have no effect on the compressor side.

Conclusion: Good thing to do, but don't be convinced that it will be responsible for a significant power gain.
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Old April 28th, 2004, 12:53   #14
bobdobbs
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Default VNT turbo in an A3/B4?

As a side note, upsolute has stated that if they made a FMIC for the A3/B4 they would also make a stage III kit. Without a FMIC they refuse to make the kit. There's a Group by for FMICs for the A3/B4 btw

[img]/images/graemlins/wink.gif[/img]
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Old April 28th, 2004, 19:19   #15
Peter Cheuk
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Default VNT turbo in an A3/B4?

[ QUOTE ]
As has been posted many times, in and of itself, a turbo swap with a bigger unit and running more boost will result in a negligable increase in HP in a Diesel if it's not accompanied by an increase in fuelling. So, I'm left questioning the claims from your source of a 15-20 HP gain from a turbo change alone, but I would say, "no."


[/ QUOTE ]
I don't pretend to make claims of making 15-20 HP from just a turbo change but the fact remains that as the revs rise the boost drops off past 3800 RPMs. I see it on my boost guage. At the Dyno Day I mentioned before, stock A4 TDI's were making almost as much HP as my chipped or bogstomper's PP520 injectored A3 Jettas. I believe that it is because the VNT turbo is not dropping off boost at high revs like our wastegated turbos and no amount of additional fuel will help this situation.

I'm actually considering a hybrid K03/K04 turbo instead of the VNT option because of the added complexity of the installation (that assumes that the compressor section of the K04 is similar to the compressor section of the K03 that is in my car).
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