Author Topic: VNT Turbos (Read 10499 times)

wolfsburgnut · « **on:** October 17, 2006, 06:53:13 pm »

I'm looking at putting a VNT turbo on my car. Started doing some research on which one to get. I have a 1.9 AAZ with a bigger pump in the very near future. From what I can see a VNT-17 is a little small for big power applications, but VNT-20s are pretty hard to find. Any suggestions?

Slave2School · « **Reply #1 on:** October 17, 2006, 07:02:19 pm »

VNT-17 will do 22psi super reliably and be uber snappy down low. How much power are you going for? Also something to keep in mind the newer turbo technology has superior flow for the size of the turbo compared to stuff of yester year.

Other folks will have more to say on that I'm sure.

*Shameless plug*
You could try to source a hybrid form a core vnt-15...I happen to have such a core that just came off my car. (sick play on the compressor wheel side it was rubbing a bit).

Benjamin · « **Reply #2 on:** October 18, 2006, 01:12:35 am »

i got a vnt20 from the 2.5tdi for sale; gt2052v (but i'm from Belgium, Europe)

a little information (better than nothing)
http://www.turbomaster.info/eng/catalogs/garrett.php?serie=GT

after the garrett T series there was the GT series wich are better, when the first VNT turbo's where made, it was called VNT-xx, now they are GTxx(xx)v, the v stands for vnt.

the gt2052v got a T2 flange, you got to search a turbo wich got a fitting flange for you, i assume this one is right. you can not just install it to youre engine, you still need to make a boost controlled vnt controller on it and you have to re-rotate them, so the oil ways are good, i thought somewhere in the french section there was a kind of "how to" from it.

The GT2052v spools up very very quick, named tintin says his turbo spools quicker than the external wastegate can react.
he got ful boost at 2000rpm on his 1.9tdi-m.
he made a system with his thottle shaft so he dont got this "overspooling" problems

i'm busy right now with a gt22v, the one from a vw t4/t5 bus. it got the same compressor side as the gt2052v (from the vag2.5tdi passeger cars)
so exaly it should be gt2252v

Greetz, Benjamin

wolfsburgnut · « **Reply #3 on:** October 18, 2006, 06:46:05 am »

Thanks for the feedback so far. I am looking for 150hp at least maybe more??? The engine has just been rebuilt so I think it can take it. The VNT-17 can only make 22psi?? That is a low I think for my hp target. I guess what I really need is a compressor map. Anyone know where to find these? As for the VNT controller, I'm almost an electronic engineering technologist, so this might make a good final project.

Slave2School · « **Reply #4 on:** October 18, 2006, 06:51:46 am »

with the vnt-17 in a tdi guys on tdiclub.com are seeing 180+HP They can handle more than 1.5-1.6bar but for how long who knows. If you are going for big numbers then the vnt-20 really seems to be the way to go and helps to limit the torque down low a bit since the turbo take slightly longer to spool up by all accounts. That could save you from breaking stuff...maybe

Audi80 · « **Reply #5 on:** October 18, 2006, 07:00:37 am »

For 150-180hp, use vnt20. These are used in Audi 2,5 V6 tdi, and are pretty easy to find from Germany ebay.

VW Smokr · « **Reply #6 on:** October 19, 2006, 02:07:53 am »

What kind of money is being talked about to get the entire Audi 2.5L V6TDI engine, or has anyone here done that?

J.R.

veeman · « **Reply #7 on:** October 19, 2006, 07:21:51 am »

Quote

What kind of money is being talked about to get the entire Audi 2.5L V6TDI engine, or has anyone here done that?

Yep... I've done it. You can read more here:

http://forums.tdiclub.com/showthread.php?t=131414

I got the entire swap kit (the 150 hp version) from an Audi A4 quattro six speed. The project has been pretty expensive so far, but my swap included everything from a donor car and there were complications.

If you wanted to just source the engine, I'd imagine you could probably get one over here for around $1500 - $2000 for basically a longblock with shipping. Start adding the accessories and a transmission and you're probably going to more than double that.

VentoTD · « **Reply #8 on:** October 19, 2006, 02:01:16 pm »

I'm working on getting my vnt20 in place. Theres just one thing... Should i use a restriction in the oil supply? On my old garret (t25) i used one 1,5mm same as it was from factory. So does garret vnt need that restriction, or are they like other bearings in the engine that are "restrictive" in themselves. I'm worried that without restriction there wont be enough oil pressure left for rest of the engine. (ball bearing turbos i know for sure need restriction or they drain out maybe all oil pressure)

Oh, and rotating the turbine seems to work nice. But i know i read somewhere that you shouldn't mess with vnt arm stopping in closed thing. Well um... change max/min position on vnt control arm? I dont see that it can get very wrong, adjust so that closed is fully closed. And check that it opens right?

Another thing i could say is that i've been using stainless nuts and bolts on my turbo applications. Some ppl say that is not good cause it dont cope well with heat. But i've noticed some positive (things?) they dont rust! and they get sticky from heat so they dont loosen themselves. When unscrewing them theres lots of torque needed and suddenly they click. Then just use one finger to spin them of, saves lots of work. Also the stainless metal doesn't seem to get "soft" from heat. I couln't round of cornes on the nuts, instead my (tool?) snapped. Had to buy new ones!

And i have to say i sort of regret my choice in downpipe plumbing... 3" is just not easy to handle. But it looks cool if i ever get it back on...

Slave2School · « **Reply #9 on:** October 19, 2006, 02:23:50 pm »

I'm not sure about the stop adjustment myself, however the vnt mechanism may need some tweaking based on your application. For my tdi I just performed a "suck" test with a hose and my mouth to see if the mechanism started moving right away or if required alot of force. Mine came form the factory set up so that minila vacuum is needed to open and it is nice and lag free. If your turbo needs more than a light suction you might want to adjust it so the slack is taken up and you don't get uber lag on a 4 cyl.

VentoTD · « **Reply #10 on:** October 21, 2006, 09:54:04 am »

So, how about that oil supply? it's getting close to startup now...

HarryMann · « **Reply #11 on:** October 21, 2006, 11:00:14 am »

Quote

Another thing i could say is that i've been using stainless nuts and bolts on my turbo applications. Some ppl say that is not good cause it dont cope well with heat.

Most stainless' cope very well with heat, what might be meant is that stainless has a lower coeff. of expansion than high carbon steels but the hot-side bodies of most turbos are made of nimonic type cast steels which also have low coeffs of expansion (c.f. cast iron and carbon steel)

The contention might be that they might loosen - unlikely!

I used stainless bolts to lock the hot-side castingto the center section and have been fine, definitely easier to undo after use.

wolfsburgnut · « **Reply #12 on:** October 21, 2006, 04:06:25 pm »

Yeah I'm curious about the oil restriction as well, as I read that as well somewhere.
Peter

Slave2School · « **Reply #13 on:** October 21, 2006, 04:31:27 pm »

When I had my turbo installed my friend put stianless nuts on and put the copper ones in the garbage

Next removal should be less of a "SNAP".

commuter boy · « **Reply #14 on:** October 23, 2006, 07:09:02 pm »

Stainless is nice, until you drop something and try to get it with a magnet......

Author Topic: VNT Turbos (Read 10499 times)

Audi80