VNT 15/17/20 differences

diesel des

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Belfast,NI
Yep im interested all right. Got to check how many days off work i have left, but it might be a goer if i can convince my girlfriend its a holiday for her too, not just a chanse for me to drive some cars.... Drop me a email with some details and i will do a bit of research into it when i get a chance. I take it you would be there too. Can you speek italian? I have enough problems with english!
 

peter pyce

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Joined
Nov 6, 2001
Toledo.... I have not checked, but I know they fly to even smaller towns, so yeah, I will not be surprised if it goes to Pisa which is right there. I will go pick him from there, if this is where he wants to fly to. Thanks for the suggestions. Anyway, we have exchanged couple of e-mails with Des and it looks like this meet will happen. This is getting way too off topic, so I will go open one in the Euro GTG section and we talk there. You feel invited to join us, and perhaps anyone else in Europe, let's meet if you are near or have desire to fly or drive


Sorry for the off topic.... moderator, feel free to delete all our OT posts.
 

dlai

Top Post Dawg
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The Insane Asylum Known As CA
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Dang, Des and Pyce on the loose in Firenze, at a GTG with babes and TDIs! Hey, take some pics for us of the babes lying on the hoods of the TDIs too! On the other hand, maybe not. What happens in Firenze stays in Firenze, right guys?
 

mojogoes

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england
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Dlai have put the R520's in yet i was not shaw if you had and is it with the new rc software, and what are your thoughts on the power.
 

peter pyce

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Nov 6, 2001
mojo where in uk are you i want to meet you when i come there let me kno' will be fun or you can come to firezne with des and test some interesting blik-blink tdi pd and also bang-bang some otherstuff.
 

dlai

Top Post Dawg
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Mojo: R520 is not in my car yet. I have the R520 but my car is not working due to the coolant migration problem. Very nasty and expensive problem! Dash cluster dead, a/c dead, sad story...Atomic is coming by my place on Sat so maybe I can get a ride in his car and experience the R520's first hand...

Man, you guys are going to have fun meeting that chip tuner in Italy. Pyce showed us some stuff last year when he was there, it was pretty amazing. So to ride in those cars and meeting that chip tuner should be a lot of fun. Oh, and those stories he told us about those babes....
 

mojogoes

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Peter your in the wrong game having said that what game are you in, its not the film industry is it
 

TDIMeister

Phd of TDIClub Enthusiast, Moderator at Large
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Peter, not to add to the OT tangent, but I was actually considering taking a Ryanair flight for a short excursion from Hahn to either Barcelona or Pisa on my trip in October... we'll have to figure something out


Those Euro bumper pics really make me want to go to meet you guys down further south.
 

mojogoes

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Peter, get your self over here to england yorkshire if thats what you guy's like a friend of mine has a club in leeds called the purple door (lap tops)but nothing to do with computers
 

Oldman

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Feb 3, 2001
Location
Leander,TX,USA
I got the VNT-20 map for Des, thanks Des,

It would appear to be the same as a GT20 map. There is a air flow line for a race TDI of some sort on the map, the line clearly shows that a 1.9 TDI will be in surge below 2000 RPM. Can this wheel be run on the street? Probably not without extreme caution on lugging the engine or WOT below 2000 RPM. After which the GT20 works fine. My though is well why not just run a GT20 as you can’t make use of the quick response of the VNT? Probably the VW racer is limited by class rules or VW racing feels that they will never bog the engine, it is a race car after all. It will never be in 5th gear at 45 MPH with a full load going up a hill. I should also note the flow line never touches the higher efficiency islands of the wheel, meaning the wheel is slightly too big. IMO the race must not be too competitive or a custom wheel would have been specified and used, or VW intended on getting more flow out of the engine later. dunno

Since this is suppose to be a stock VNT20 wheel I would have to assume my flow calculations are off by 10% to 20% since for the 2.5 TDI. I would say the 2.5 TDI stock has to run very close to the surge line, just like the 1.9 TDI VE.

I should also note long race piping and FMIC tend to soften the initial air demand moving the demand line to the right away from the surge line.
 

peter pyce

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Joined
Nov 6, 2001
Guys, this may get even better, but I really feel bad for the topic starter and the rest of serious participants, so let's go talk somewhere else about euro bumpers
In the Meets/GTG Section, European, there is a topic about our trip, let's talk there..... I feel some nice international GTG may happen somewhere in Central Europe


P.S: Oldman, I am surprised the VNT from italy did not made you say something. IIRC you asked me for those long time ago, so ehre they are..... But hands down, your candy is still the best!
 

mojogoes

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Guy's just a bit off topic , you got to look at the www.seat cupra.net site,forums,then tdi's, topic air intake on pd 160, have fun
 

diesel des

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Aug 19, 1999
Location
Belfast,NI
Oldman, isnt kerma running this comp on his pd 150 hybrid? I found that while useing it you needed to set the boost up so that it was restricted to less than 15psi below 2k RPM with rising to a max of 25PSI AT 2.5k + rpm. The VNT got the turbo to that boost REAL fast. Way faster than a GT would no doubt. I still think the VNT has a big advantages over the GT even with the same comp wheel. I used this comp on the A3 ecu that was set up for a GT turbo. I used a lot of weird and wacky plumbing of valves to get the boost response i wanted, but once set it was great with NO ecu problems.
 

Oldman

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Yes he is, my thought is since a GT20 has minimal boost below 2000 RPM and can hold 24 to 26 PSI no problem in the mid range and all the way to red line, it really works just as well as a VNT20 wheel hybrid that is setup to limit boost below 15 PSI by 2000 RPM. The GT20 would seem to be at full chat by 2200 RPM, about the same as a limited hybrid. Since a race through the gears uses about 1100 RPM, I would think that 3200 to 4300 rpm is where the GT20 is most happy. At that range the VNT has no advantage at all, and since the GT20 has a much bigger and smoother exhaust flow from head to down pipe, I would think that the PR would be about 2.0:1 ( I have not measured it) vs 3.0:1 for a VNT with the larger .65 A/R. That is a full 26 PSI LESS backpressure and heat in the exhaust manifold. Little wonder why the UPS III has little smoke and is much faster thru the gears.

I should also add that on my PD150 turbo, race injectors, chip, no dawes, I see about 28 PSI on surge 24 in the midrange, 21 psi at redline. With dawes surge is to 24 PSI and she is flat from surge to redline at 21 PSI, with more smoke.
 

diesel des

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Location
Belfast,NI
I think that the variable AR of the turbine on a full VNT20 would keep the preasure ratio (Exhaust) lower at 4250 rpm than a GT20 set up with a fixed ar on the turbne to give good boost at 2200rpm. The VNT 20 on a modded SDI manifold looks good to me in terms of flow oldman. Did you see the pic i posted of the mock up?

Also punch a VNt 20 car at 2000 rpm beside a similar car with a GT20 at the same revs and the VNT 20 will be a car ahead befour the GT has spooled. Ok drop a gear and keep them both above 3K and little diference but its so easy to get caught with your pants down with a engine that needs driven like that. EG VTEC. Thats where a good VNT tdi is QUICK. I drove older vw diesel with big fixed ar turbos for a long time. I am never going back to those lag days. At say 1500rpm the VNT 20 could make 10 psi from memory without surge. The car pulled well. A GT20 car would only be making 3-5psi at that condition and would be a bit of a dog. I liked the progressive nature of the boost spool with the VNT 20 COMP. VW motorsport would of had a GT20 to try im sure. If it had of been better why didnt they use it. They have more money than most of us put togeter.
 

diesel des

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Some more numbers for you oldman from a vw paper with a 1.9 190bhp engine with the vnt 20. All figures at 4000 rpm

Boost 1.72 bar
Exhaust back pressure 2.39 bar
TIT EGT. 588 deg c
Bosch smoke value 2.4
Comp outlet temp 178 deg c
Engine Charge efficiency 2.43
Compressor speed 179K

They had some other figures with the boost set up and down a little from here. This showed a lower EGT and more back pressure obviously at higher boost but a higher charging efficiency. Just look at haw clean this engine was with less than STOCK black smoke. Stock is 2.5 bosch. A typical chip yields a 5.5 bosch. The EGT figures are supper cool for a TIT. Surely this says some thing for a vnt20. Also just think how much power a dirty, hot version of that engine would make…. They were limited to a racing smoke value just like stock of 2.5. But the rally cars wernt hence talk of 250+ BHP.
 

Oldman

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1.5 PR from intake to exhaust is very good, so you are saying they are running a the whole VNT20 right not just the intake side.

Yeh I saw your picks, the VNT20 on the SDI manifold look really good!
 

TDIfreak

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Talking about the differences, GT22v that is used on the 150 hp T4 (074 145 703E), has still larger turbine than the VNT-20 used on the V6 tdis. GT22v has 43mm exducer and 49mm inducer compared to 38...40mm and 47mm on the V6 VNT-20.

The compressor side is 38,5mm or thereabout on both. There are little trim differences on the various VNT-20s used on the V6s.

Wonder if the VW team used VNT-20 or infact the gt22v?

The bigger turbine will help lower the exhaust back-pressure, but will it sacrifice the low end too much, that is one question I wanna find out. Surely the surge is less of a problem.

Searching for SDI manifold and T4 downpipe...
 

diesel des

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Aug 19, 1999
Location
Belfast,NI
Yep they use a complete vnt 20. They dont give the part no of exactly which one though. Also no idea what manifold they use on the exhaust.
 

diesel des

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Joined
Aug 19, 1999
Location
Belfast,NI
I was useing the GT22v compressor on my vnt 15 hybrids. I was running a slight cutback on the compressor to reduce surge and allow 20psi at 2K rpm. I think they where useing the VNT20. The vnt15/17 has a turbine of only about 43mm, so even the vnt20 is a BIG step up in flow and reduction of back preasure.
 
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