Beater Build: vnt15 1z

I figured I should post a thread on the current car I'm building.

1997 Passat w/208k miles (and some residual damage from a WI deer) and a dead hole.





Game plan:
1) remove drivetrain from car (head already removed)
2) swap in a used shortblock (194k AHU - Thanks Kirk!)
3) install vnt15, need an early mk4 turbo drain line
4) clearance mount bracket and mount
5) mk4 MAF (thanks for the tip mrchill!)
6) early mk4 N75
7) Sachs VR6 clutch
8) idparts vnt15/1z downpipe
9) PP520's (? open to suggestions here)
10) Rocketchip 2 (3 or 3+ if the clutch will hold it)
11) stock intake with the option of a PD130 (driver's side) later on
12) swap some wires on the clutch for cruise

Add one good AHU shortblock


(image borrowed from Kriesel from his thread)

Add vnt15 and clock cold side 180deg



Of course the mount wouldn't bolt up with the vnt15 in there (the turbo itself sits probably 2" further towards the passenger side) so you have to clearance the mount. Here is where I started:


bracket and mount modified:


1z TIP even bolts up to the vnt15!

And i got a quote of 5k to do this even though i had most of my parts. I abandoned that project quick and park the mk3.

You would need a MSA15 ECU in there as well to support a vnt file (you 1Z most likely had a MSA12 ECU)

Nice .
I put a VNT into my passat late last year, worked great.
A couple of pointers :

1. early N75 - you don't need one. Just repurpose your existing EGR N18, it is the exact same part number. I simply swapped the two (N18 and N75), so the ECU still has a load on the EGR control lines.
2. Motor mount. Yes, you can cut it, but be very careful as that cast aluminum will stress crack pretty easily. Another option is a steel Mk3 mount, Kyle sells them ready to mount. Works really well.
3. You don't necessarily need to change ECU, depends what you have, some came with GQ. I sent my GQ ECU to Jeff (Rocketchip) and he made it work fine. Pretty sure others can do the same, it is a well known swap. He also did a 3bar MAP for me, but I guess you will not need that with the 15 ?
4. Downpipe. Either weld your own, or if you want bolt-on, I had Peter at IDParts make me up a Mk3 2.5" DP, but with a Mk4 flange/VNT turbo location. It fits perfectly, and was the same price as the Mk3 2.5" DP.
5. I am told the Mk4 MAF is not needed, but I am interested to know what you find out.
6. Your VR6 clutch should hold 2 or 3 ok. When I went to RC4 as part of this swap it started slipping. I have SBCIIE now, holds good.

For reference, mine is GT1749vb running 23psi, PP520s, RC4. It is a BIG difference from previous setup (GT15 running 18psi, PP520s, RC3). No smoke now, burning all the PP520s are delivering, good bump in power.

Enjoy !

Thanks for the tips Charlie!

1. I had one on the shelf but if the n18 works then I'll go that route
2. Mount is obviously already cut and will be welding it up soon. Thanks for the link - I'll keep that in mind, I'm not even close $189 into the mount modification but I can see how a larger cold side (anything bigger than a vnt15) would require you go with that mount.
3. I'll have to check which one I have.
4. Is it possible to modify the mk4 DP? When I get the motor in the car I'll give it a look but I think $400 for a downpipe is kinda steep IF I can get this one (might be a hybrid of the mk3 and mk4) to work.
5. Based on the info I've gleaned from mrchill, the mk4 MAF offers greater headroom (able to measure high air flows better than the mk3) and finer resolution which results in better driveability and increased FE.
6. Good to hear.

So you have no airflow mods besides the turbo and DP? Stock intake, intercooler pipes, intercooler, TIP? While you might not gain from these upgrades with the bigger snail might the vnt15 I'm using benefit from some airflow mods?

I like the tip about the EGR's valve. Thank you CharlieT, I too have a Mk4 N75 but no I don't have to get the plastic plug to swap the connection.

For the downpipe I found on my 1st tdi corrado that you can use the Mk4 TDI downpipe without issue. It will be dam close to the steering rack but it fits. Whitebread agreed with me in one of his build threads from last year about this so feel free to confirm with him.

Man I tried hard to get a Mk3/b4 TIP for my ALH Corrado and I could never get one for a reasonable price (at the time I wasn't sure if it would swap over perfectly so i didn't buy a new one). I made one out of steel but boy I now wish I had bought one new.

It is very tight with the mount without any trimming - I can clock the cold side to gain more clearance but that will also push the top closer to the cam sprocket. I think I have it where it needs to be (lines up with the intake mani attachment bolt).

I do believe I am going to need to rotate the top portion so it doesn't point at the strut tower as much - I'll know more when I get it in the car. Should be a simple mod though since it is already a glued assembly.

Here is mine..








The 2.5" Mk3 Downpipe, but with Mk4 turbo flange was well worth it, it fits perfectly. It wasn't $400 either, but that was 8 months ago.

As you can see I still have the stock SMIC for now. Temps are 90 here now and I see IATs of ~125 after a hard accel, but drops to ~10 above ambient crusing on the freeway. I plan to fit a FMIC before the summer, but I have other car priorities right now (TTq TDI).
Intake is a PD130/150, works great. I tapped a 1/8" NPT port in the rear with a 90 fitting, so I could hide the McNally boost sensor back there.
TIP is custom, made from a 2.5" 90deg aluminum pipe, cut at a tangent, with a 2.5" x 1.75" silicone reducing elbow to the turbo. I trimmed the stock accordian back, and it fits perfectly to the OD of the 2.5" pipe.

Hey C.T. I'll buy the TT!!!

Mount & bracket modification detail

As you can see in my previous mount picture I penciled on the mount where the cuts needed to lie - I ended up being pretty close but hopefully these pics will help others make those first cuts.

Blue lines are the parting lines of the casting.






From there I trimmed the right side until I didn't hit the turbo (furthest right portion)


What's nice is I can use the piece that I cut out as a reinforcement - I'll trim this down a bit so I expose a bit more face for the weld. I'll also fillet any of the sharp corners.


What's weird about the isolator is the fact that is looks like I trimmed A LOT of material but I actually didn't (I've heard Whitbread say this as well) - I removed maybe 1/4" of material from the actual rubber.

Nice install Charlie.

I'll have to keep an eye on this thread, I've got an AGR engine (similar to the ALH) but it has the wastegate turbo and MSA15 ecu.

Which style of mounting system do you have? mk3 or mk4?

Looks like an FA ECU - am I going to need to find a GQ?

FA ECU can be used for the VNT swap.

Is that what you have?

Yep, Mark tuned it for an EF chipset, which is from the Seat Toledo AFN.

FA is the most updated US b4 chipset btw, GQ is one below and for the 96's,

Little more progress



I'd send out the ECU but I can't get somebody to answer an email

greengeeker said:

I'd send out the ECU but I can't get somebody to answer an email

Click to expand...

Had the exact same issue. A certain well respected vendor didn't answer emails about tuning my 96 passat (GQ ECU).

Mark Malone emailed back the next day. His tune is in my GQ now.


High in the woot factor

you still need that early mkiv drainback line?

greengeeker said:

I'd send out the ECU but I can't get somebody to answer an email

Click to expand...

Probably have to call.

I'd be surprised if you can't get Malone to answer an e-mail. Might take a day or three but he's usually pretty good at responding.

I can also confirm that running the old style N18 valve in place of the N75 works just fine. I'm running mine right now because I haven't swapped back from when I was diagnosing some stuff.

Jon

jimbote said:

you still need that early mkiv drainback line?

Click to expand...

Thanks for asking Jimmy but I don't. I tried a normal drainback line and it fits fine.

I'll give the n18 a go.

Next thing I need to verify is what needs to be done to swap in the mk4 MAF. Push the pins out and simply install into a mk4 connector?

The EGR valve will work but the passages in it are alot smaller than in N75. At least in ALH that is. It will control boost but it takes longer for it to be able to move the actuator from one extreme to the other. So be careful with first tests and watch your boost gauge

hatemi- I was unaware of that - mine seems pretty quick.

Nick, You could run MAF-less too. I've been running MAF-less since December.

Progress

This project has been delayed a bit after being in the Middle East for 3 weeks followed by losing a fellow firefighter.

Anyway, after a few late nights I have the shortblock back together (all new seals, intermediate shaft bearings) and in the car along with the transmission, ECU, accessories, coolant hoses.

I'm starting to look at the downpipe a little more seriously so I grabbed both turbos and their downpipes to see how it would line up.







So they seem to line up pretty well and the ALH pipe slips tightly over the AHU pipe so I might be able to get by with a single cut on the center pipe and simple guillotine clamp. We'll see when I get the head in there. Notice the shift from left to right of the turbos' center sections - this will present some issues with the oil lines as well as the TIP which will likely need to be clocked at the top to avoid missing the strut tower. Again, we'll see when I get the head installed.

I'll start routing the vacuum lines to the N75, new CV boots on the axles....

I found that they are close...but no cigar. I was of course using 2.5 inch dp's though. Idparts has an p&p dp for the mk3\b4 that mates up to the vnt 15\17\hybrids. Thats what I have been using for the last 3 or so years.

Where exactly was the problem point when using the ALH? Something I can work around?

Something odd that has come up is where peak torque will occur with the RC2 setup we'll be running...Jeff says the soonest it can happen is 2200rpm. Is this in-line your experience Chris?

What sort of gain/power are you aiming for with your build? I heard fom ryanp that he got his caddy van upto 157bhp there abouts with a similar set up but on an ALH with a tune and nozzles. Also what sort of money is it to get the ecu sorted out? I take it you're getting it chipped and tuned?