MK3 Jetta with VNT-15 swap, tune, and supporting mods: PP520's or PP764's?

Hey guys,

Planning a VNT swap in my MK3 and wanted some advice. I already have a used VNT-15 in good condition and PP764's waiting to go in. In addition to these, here's my hypothetical list of mods:

-EGR delete (already done)
-upgraded intake piping
-upgraded intercooler piping, PD130 or 150 intake
-2.5 inch downpipe with magnaflow cat and 2.5 inch exhaust
-some sort of lift pump (Walbro FRB-11 looks good)
-RC tuning

I was talking to Jeff at TDIFest and he said that PP520's would probably be better for the task. I can trade for them, that's no problem, but it's always possible that I'll get a bigger turbo in the future and an FMIC. So my question is should I install the 764's alongside this project? I'm not sure how much Jeff can modify the tune for the nozzles in my specific case, but I'm looking to have minimal/no smoke if possible. Can I do it with this setup? Jeff currently has an ECU of mine and is going to work on it and send it out so I can swap it in when doing the conversion; I'd like to be able to discuss all options with him.

yes most certainly put the pp764s in . if you have any thoughts even of further tuning and bigger turbos.
i was in the same position a year or two ago and went for the pp520s because they would work best . and at that point i thought that chip and injectors was as far as i wanted to go .
but now i find my self with a whole host of mods including stage 3 clutch and vnt 17 turbo . and if id have gone for pp764s to begin with i wouldnt be underfueling the 17 now.
bigger injectors can always be turned down with the tune but smaller injectors cannot push more than there max .
at worst you will find the pp764s on stock turbo a little more smokey and a little worse on fuel .

Hey, thanks for the response. The 764s are quite a bit larger though. What I am interested to know is will a PD130/150 intake and upgraded intercooler piping make a difference? Would it make a difference with 520s, 764s, or both? I need an downpipe/cat/exhaust when the VNT goes in. But I could easily go either way and never get an FMIC or a bigger turbo than the VNT-15, and thus I think that PP520's would be almost perfect. Lift pump is going in for sure, I think it'll do a good job helping my almost 200k mile injection pump.

Running a 15 in this application is edgy, so you definitely want to run the Pd130 intake and improved intercooler piping. Also a larger intercooler and a serious exhaust. Jeff can tame the fuel of the PP764's so that isnt an issue. The turbo inlet should also be a decent size and not kinked in any way. Use a Mk4 MAF minimum. Lift pump is a must on a MK3. If you elect to not put in a larger intercooler you will smoke much more and make less power than you otherwise would. The PP520's are good for 180whp and better with 11mm pump head.

Chris, why the move to the mk4 maf? First time I've noticed this suggestion. Any difference in plugs when doing so?

BTW how's the 2056 coming?

Chill, you da man! I really enjoyed your talk at the fest. I think you've helped me make a decision; PP520's are my best bet.

While I'll keep the PD130 intake and larger intercooler as ideas for the future, it's not something I'd like to incur expense for right now. I'll try intercooler cleaning and we'll see how my intake is doing as well (did the cleaning a while back). Larger intercooler piping will be done as the VNT will need something custom anyways, and I'll modify the intake (piping, at the least) in some fashion so it is larger and smoother.

Regarding the MK4 MAF, I never thought much about my MAF. It's a pierburg and has never given me any apparent trouble. I didn't think that a MK4 MAF was compatible with a MK3 but I guess it's all in the programming, eh? Are the harnesses the same? What are the advantages of a MK4 MAF? Does it give higher airflow readings, such that you can have more control? Obviously I want the one from an ALH, right? (PN Bosch 0 281 002 757 or 038 906 461C)

I'm going to use a new style N75 (not one from the early A4's cause they are more expensive) and modify the harness. Not much more to say!

Blake we need to talk.
Jeff

calling!

Thanks Jeff, good talking to you.

You will be very happy with 150hp/250ftlbs AFN setup, low smoke car that is capable of 60mpgs.

The vnt15 will give good snap and throttle response with RC3+ and pp520's, and should last many miles.

Jeff ;-)

Indeed! The Mk4 MAF allows finer fuel control and less smoke. The connectors are different, but Jeff can give you a diagram to swap them. B the way, my car can get(has gotten) 55 mpg with this setup.

Edgy, Chris? How so? I'm considering this setup and would only do it with a better than stock downpipe (I'd probably stick with the 2" size that's in the car, but obviously it would have to be swapped out to fit the new turbo), CAT delete, PD130 intake, and an A4 MAF. And I'd probably run Sprint 520s unless I upgraded the intercooler. Even then I think the car would smoke a bit because of more primitive fueling and electronics.

Chill and I differ a bit on this: I like less fuel, less torque, more top end, as little smoke as possible. Right now my A3 is running RC3+ with the stock turbo and nozzles, lift pump, 2" exhaust, no cat. It's really nice.