Exhaust manifold for VNT-20 into Rabbit?

Hi guys,

I'm installing a 1Z TDI (mechanical) into an 82 Rabbit Pickup and have a question regarding exhaust manifolds. I will be running a VNT-20 turbo and would like to know what available manifolds will fit back there. I'd like to run a gasser A1 intake manifold. Am I wrong to assume any 8v turbo manifold will work (ATP, etc., which iirc mount the turbo plumb on the back of the manifold), or will it require one that points down slightly?

Will the turbo be oriented correctly, or will it need to be "clocked"?

Will the stock 3 hole TDI manifold work if I make an adapter plate? (again - fitting specifically into an A1 chassis)

Also, what style flange does the VNT-20 use (exhaust) - a T3 style?

I don't have the turbo in front of me yet, so I can't figure this out for myself at the moment, but I'd like to source all the parts I need so the swap will go quickly.

Thanks!

Mark.
75 Scirocco
82 Scirocco
82 Caddy - mTDI swap in progress

PM Passenger Performance. He's got my VNT 20 right now and is working on an exhaust manifold for a VNT20/MKII. He should have the info you need. He might even be able to make one up for you, including the downpipe.

how are you going to mechanically control the VNT 20 since your going mTDI and not using an ECM, etc. to control operation of the VNT 20's vanes? Going to use a flipped acutator, etc. and use boost to operate them as per the writeup on www.vwdiesel.net regarding converting a VNT 15 to work mechanically? Or find a mechanical canister out there somewhere?

Very interesting ...

As for the manifold configuration. I use a 8v turbo manifold with a standard T3 flange at the moment...for VNT, you'd need the triangular flange and the information provided above is good.
Clearancing the MK1 intake manifold from a gasser, (I had this on my IDI TD that was built to the hilt about 4 years ago initially) requires some clearancing on the back side of the intake manifold itself. Also something HUGE you have to take into consideration is using the 8v gasser intake manifold which has oval ports on it and having to port them out to "D"ports like the TDI head has to not disrupt flow... its a challenge on the 8v intake manifold. On my current mTDI setup I was able to JUST port out a corrado G60 manifold to Dports...but there isn't alot of material there and I don't know as if I'm entirely happy with it at the moment. Hence, working with a non turbo AAZ manifold this winter which already has Dports from the factory and very much resembles the gasser intake manifolds... ALOT of considerations here...
The G60 one I used with a modified boost return section of the throttle body on the G60 required quite a bit more clearancing on the backside of the intake manifold because it sweeps back even more. I ended up spacing the turbine inlet flange a bit, otherwise the compressor housing of the turbo hits against the intake manifolds backside and will not allow a bolt up... this is with the compressor side inlet on the P side and the discharge on the d side of the car...

You can see the use of the MK1 GTI intake manifold on this pic of my original IDI TD build...sold last year in place of getting the TDI to install...


Here is the G60 intake manifold I'm currently using...

installed in the car

and the current turbo...


Don't have a picture of the non turbo AAZ intake manifold up at the moment...suppose I could go downstairs and snap one though...

Joe

The VNT 20 has a standard T3/T4 bolt pattern I believe (rectangular). The collector is round. Named Tintin on vwdiesel (French side) setup his VNT 20 to actuate the vanes in conjunction with the throttle cable. Here's a couple pics.







A couple videos...
http://video.google.com/videoplay?docid=-8726487528543720960

http://video.google.com/videoplay?docid=3448331191659563820

Here's the link (if you can do french....if not, ask and I can translate some of it....he's got video too).
http://vwdiesel.net/phpBB/viewtopic.php?t=2848&start=0

I remember seeing that, and it seems to work very well for him. Though, I believe that it would be nearly impossible to use the MK1 gasser intake manifold if he went the same route as TinTin did on vwdiesel.net
Revisiting a PD intake manifold could be in the future though on my end as well. The larger intake manifold is nice...and I'd really like to see what the difference are between stock and plenum style are on a dyno sheet prior to a decision. the mechanically operated VNT is pretty cool though and the boost response was pretty instantanious. Though...did you notice a spike or two in the video before it finally leveled out? Its hard to tell..but I thought I saw this...

Very cool setup though...and the vids I remember showed the linkages operation pretty clearly
What would be more interesting to see...and its been "tossed" out there before... a seperate eletronic control unit that could somehow work with the mTDI setup but still use the VNT's electronics for vane actutation... I'm not an electronics guru, etc. but I'm sure someone out there somewhere has an idea of "how" this could work

Joe

RabbitGTDJoe said:

how are you going to mechanically control the VNT 20 since your going mTDI and not using an ECM, etc. to control operation of the VNT 20's vanes? Going to use a flipped acutator, etc. and use boost to operate them as per the writeup on www.vwdiesel.net regarding converting a VNT 15 to work mechanically? Or find a mechanical canister out there somewhere?

Click to expand...

I've done a bunch of research over the last month, and I've decided to take the best of the ideas I've seen and make my own version. I like Named Tintin's system using the accelerator position to control the VNT vanes, with a boost can overriding the pedal input when boost reaches a preset limit. My spin on this idea will be a self contained controller mounted to/near the injector pump that incorporates a completely adjustable non-linear (or *near* linear if desired) mechanical output (via cable) to the turbo. The packaging of this controller should open up more choices of turbo or intake manifold placement and selection, and be a less "clumsy" setup. I'm still in the design stage with this though, so I still have some details to work out...

RabbitGTDJoe said:

Also something HUGE you have to take into consideration is using the 8v gasser intake manifold which has oval ports on it and having to port them out to "D"ports like the TDI head has to not disrupt flow... its a challenge on the 8v intake manifold. On my current mTDI setup I was able to JUST port out a corrado G60 manifold to Dports...but there isn't alot of material there and I don't know as if I'm entirely happy with it at the moment. Hence, working with a non turbo AAZ manifold this winter which already has Dports from the factory and very much resembles the gasser intake manifolds... ALOT of considerations here...

Click to expand...

Definitely... I was planning on building up the A1 gasser intake where required with my welder and porting it to fit the head.

I didn't realize how small the stock 1Z intake is till I had it in my hand the other day! Wow, that thing is small!

RabbitGTDJoe said:

Don't have a picture of the non turbo AAZ intake manifold up at the moment...suppose I could go downstairs and snap one though...

Click to expand...

Hmmm. I'll look into this option.

Thanks for the reply!

Later,

Mark.
75 Scirocco
82 Scirocco
82 Caddy - mTDI swap in progress

Mardak said:

I've done a bunch of research over the last month, and I've decided to take the best of the ideas I've seen and make my own version. I like Named Tintin's system using the accelerator position to control the VNT vanes, with a boost can overriding the pedal input when boost reaches a preset limit. My spin on this idea will be a self contained controller mounted to/near the injector pump that incorporates a completely adjustable non-linear (or *near* linear if desired) mechanical output (via cable) to the turbo. The packaging of this controller should open up more choices of turbo or intake manifold placement and selection, and be a less "clumsy" setup. I'm still the design stage with this though, so I still have some details to work out...

Click to expand...

That is something I'd def. like to see and if you can make it work...even more so. Where there is a will...there is a way, and if you can get a VNT to work mechanically with a different, larger style plenum intake manifold (kudos by the way on building up the Mk1 gasser manifold to support the D ports...I may do this on the G60 one if I don't like the fitment of the aaz non turbo one) you'll have advanced one more way making mTDI's more favorable. It'd be really cool to have balanced, accurate control of the no lag VNT on the mechanical setup...it'd open up a whole other world of options...

Let me know if you have further questions, etc... always around to help...

Joe

Techtonics Tuning in Oregon will sell you the 3-bolt exhaust flange for the VNT for $25+shipping.

kitambi said:

Techtonics Tuning in Oregon will sell you the 3-bolt exhaust flange for the VNT for $25+shipping.

Click to expand...

Doesn't the VNT-20 have a 4 bolt flange? IIRC the one I'm interested in buying has a 4 bolt flange (T3, or T4 style?)...

Later,

Mark.
75 Scirocco
82 Scirocco
82 Caddy - mTDI swap in progress

It does, but it sounds like the manifold he's got is a European one for the 2-piece VNT-15, which had a triangular flange.

Vnt 20

Those pics from Named Tintin show him using a 1.6 TD exhaust manifold with an adapter plate, which mounts the turbo at a 45 degree angle to the block, pointing up. Not much room for a gasser manifold there, and I think the ATP style manifold might have the turbo real close to the firewall; close enough to hit when the engine shifts to the rear when accelerating.
Now I have never seen a VNT 20, but I do have a PD130 VNT17 that I'm working with, and I thought they might be similar. I can tell you the 1.6 TD manifold when mounted upside down puts the VNT17 in exactly the correct position, as far as oil feed and drain go. I had considered clocking, but the turbo design looks to make that difficult. The bolt pattern is different, but 1" thick ductile grey iron from Mcmaster-Carr is pretty cheap.

I'm using the ATP 8v manifold...no issues with clearancing or hitting the firewall on the car with the T3 I'm running, which I think should be comparable in dimensions with the VNT's compressor housing. I even have an adaptor/spacer plate in between the manifold and turbo inlet flange to space the turbo back a bit farther so the compressor housing will clear the gasser intake manifold.
How "wide", or whats the diameter of the VNT 20's compressor housing at the widest point? I could measure mine with the ATP manifold to see in comparison if you need it...as its in, installed in the car, etc...

This is on an MK1 of course...

Joe

Here's a side view of my VNT-20, which shows the collector flange. The turbo is probably still smaller than a T3.

yum yum... wait... STOP STOP... your starting to make me thing about things and the car converted from the wastegated setup to a no lag VNT setup...

doh...

Joe

Yeah, well Dave at Passenger Performance did the same thing to me. I feel less bad now

So, on that note....

Thanks for posting the pics! I'll be picking up my VNT20 next week, so it's nice to get a sneak peak...

So, just to confirm, what flange type is it? T3?

Thanks,

Mark.
75 Scirocco
82 Scirocco
82 Caddy - mTDI swap in progress

might have to look for a VNT-20 and see how I could convert it as well... hmm...price...going about it mechanically...or...seperate control program to use the electronics....something...the gears are turning...

Joe

Here's a quote from Passenger Performance, who has my turbo for a science project.

"it is a T25 flange, but the port is vnt specific so a regular t25 flange will not match, but the bolt holes will. A t3 flange is bigger."

i agree with that...the t25 flange looks like the t3 flange...but is DEF smaller... I found this out the hard way when I needed an spacer flange for my mTDI setup and bought a flange that said it was a t3 one...got it here...NO WAY... T3/T4 flange, is same....but the T25 is def. a different beast...

I may have a comparison pic if I dig through my conversion stuff...

Joe

dubCanuck1 said:

"it is a T25 flange, but the port is vnt specific so a regular t25 flange will not match, but the bolt holes will. A t3 flange is bigger."

Click to expand...

Anyone have pics that show the difference between the regular T25 flange and one that'll match the VNT20's? Do the ports at least line up (ie: is the only difference the size of the ports vs. location?)

Thanks!

Mark.

Here's the T25. Compare with my VNT20 up above. I imagine you'd have to actually add material to this one to make it fit up perfectly with the round hole.

I remember a place that would custom cut flanges for setups as long as you provided them with a mock up, template, etc. Laser cut, etc. for not such a bad price.
I believe it may have been over on the vortex...maybe on vwdiesel.net but I'm leaning more the other way. I'll see if I can't dig that up. They should be able to get a "T25" bolt pattern flange but cut the hole for the center just the way you want it.

I'll do some digging...

Joe

RabbitGTDJoe said:

I remember a place that would custom cut flanges for setups as long as you provided them with a mock up, template, etc. Laser cut, etc. for not such a bad price.
I believe it may have been over on the vortex...maybe on vwdiesel.net but I'm leaning more the other way. I'll see if I can't dig that up. They should be able to get a "T25" bolt pattern flange but cut the hole for the center just the way you want it.

I'll do some digging...

Joe

Click to expand...

That'd be great, thanks! I'm now leaning towards welding up my own 'weld el' log manifold and not having to fabricate the flange will save me some time...

Later,

Mark.

here is one of the sites I remembered...

http://www.davesport.com/cgi-bin/davesport/flanges.html?mv_tmp_session=1&expandall=1


You might even want to give ATP a call and maybe they can work something up for you as well... getting closer...but I know they have alot more selection than what is listed right on the site.

http://www.atpturbo.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=ATP-FLS-051&Category_Code=FLG

Still looking for the big laser cut one I remember previously...

Joe

FYI, laser / plasma cutting is a common industrial process. If you can make up a to-scale drawing showing what you want, you should be able to get it made at any industrial shop that has the equipment to do it.

It is fairly common....but finding a shop that specializes in making custom one off flanges, etc. is different than shops that have other jobs to do, etc. I tried to have a flange cut locally last winter, as well as my pistons machined and I was going to get charged a regular "job" rate from the local shop here because they had other projects to do...


Joe

I have a vnt20...and it will not work with an ATP style t-3 manifold..one because the bolt hole spacing is wrong, two the turbine housing is too big. If you have the t-2,t-25 flange welded on by ATP it only makes matters worse. I even have a callaway manifold that is drilled for a t-25 bolt pattern(factory spacing was for a true t-4) and the turbine housing still hits the firewall.

If you want to massage the firewall, I guess it could be made to fit..but who wants there car to look ghetto.

I bought an Audi tdi 5cyl ex mani and had the 5th cylinder removed...the mani is a very, very low profile and it might work. I haven't had time to mock it up...the only problem I see is the mani's outlet is offset and it may put the turbo too close to the frame rail on the pass side. The way it's designed you cannot flip the mani because the exh. mani will hit the intake mani.

I researched the daylights out of this...I think one way feasible way is to flip a 1.6td mani and have an adapter made..it looks like it will clear the axle. haven't even got to the downpipe yet.

Yeah. What I was originally planning to do is the same as what namedtintin did, which is just to mount an adapter plate up to the stock 1.6TD manifold, which pitches up the face of the outlet. The VNT I've got, once the vaneplate's rotated so that the turbo sits at 10:00 (when looking at the passenger side of the car) and the oil feed/drain is vertical.

All VNT20's aren't created equally. NamedTintin's had the holes for the vaneplate offset by 60 degrees from mine, so he had to drill and tap the inside of the turbo to get the same orientation as me.

Passenger Performance is making my manifold, so I let him have my turbo for a while for some mad science. Can't wait to see the finished result. It should have the same orientation as the setup I described above.

I hope that helps.

Im not sure but you could use your 1Z manifold with adapterplate. At least that works for MK3 and 4 cars with AHU and AGR manifolds, and IIRC the 1Z mani is identical to the AHU. You can make an adapterplate that has the 3 holes for bolting the plate to the mani(machined so you the allen/Torx head bolts go deep enough) and 4 tapped holes for ataching the turbo to the adaptor.

Contact DIESEL DAZZLER. He is located in Dorchester, Ontario right outside of London.