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#45
by
bert
on 29 Dec, 2007 06:14
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same as stewardc 1.6 top welded to 1.9 bottom with flexi pipe still,bolted to block
Bert
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#46
by
bert
on 29 Dec, 2007 06:31
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You want to see the turbo vnt fitted to the citroen c3 you can drop it in a cup of tea :lol:
Bert
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#47
by
jimfoo
on 29 Dec, 2007 06:37
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I'm surprised no one mentioned that you will be blowing head gaskets left and right at 35-40 psi. I hope you are taking that into consideration.
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#48
by
jtanguay
on 29 Dec, 2007 14:11
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i just used a 1.6 pan/sump
ok so vnt is the way forward, but sounds to me like id go through about 1 per week so its out of the question for me, as i hav no money just friends with a scrap yard and doubtfull id find loads of these, i thort up an easyer way to get rid of lag, all you need is old scraps of metal an alternator and a bit of time,
esentualy atatch a shaft to the turbine in the turbo and then take the clutch wheel off a tdi alternator and uve got a super charger that when the engine produces enough gasses will then turn into a turbo :wink:
i call it the superturbo :idea:
did i just invent sumthin?
honda made a turbo that spooled with an electric motor. i think the idea was great an all, but for reliability... its absolutely out of the question. now if you were going to try and extract some shaft power through gear reduction.... :twisted: the turbo could probably produce 10 hp @ full song. 100:1 ratio = mad torque, but i could see turbo failure if you were to suddenly engage it without any sort of clutching mechanism.
i wonder if it would be possible to make a magnetic bearing turbo, and somehow scavenge electricity from it, or make it produce its own magnetic field with all that kinetic energy? spool would be even quicker and smoother... :shock:
i'd say minimum of a VNT-17 for 15-20 psi boost, and that is pushing it. i'd like to see the exhaust backpressure at 20 psi on a VNT-17, as with vnt's you're more concerned with that.
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#49
by
subsonic
on 29 Dec, 2007 14:21
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I read somewhere that on some of the new makes of diesels with cats, that the engine would periodicly surge the egt's to burn out any build up of soot etc.
Would an occasional egt spike like this help burn out any build up inside the vnt turbo's?
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#50
by
euglen
on 29 Dec, 2007 15:26
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#51
by
gldgti
on 29 Dec, 2007 15:50
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I've taken apart many wastegated and VNT turbos and can say that there is nothing more robust about a wastegated turbo. I do however believe the information that there are more turbo problems now with new vehicles than there were in the days wastegated turbos. There are three reasons for this as I see it. One is that the turbo vanes have very little room for movement on the VNT. Any carbon buildup will quickly cause the vanes to stick. The second is that they spin a lot faster and will easily surge under the "right" conditions. In an attempt to eliminate turbo lag, the turbos fitted to most new applications are IMO too small for the engines they are being fitted to. I have a KKK that was fit to a 1.9 TDI that looks like it would fit a chainsaw. I can't fit my thumb in the compressor outlet. The conditions where the turbo will be damaged are then attempted to be controlled by the computer. Any issues with the sensors or control system over any period of time can result in significant damage to the turbo. The final is that there are quite a few "turbo problems" that are actually problems with the sensors or vane control system itself. I think that you would be hard pressed to blow up a VNT unless you ran one that was considerably too small and ran too much boost through it consistently. I also think you would need one of considerable size to hold down consistent levels of 35-40psi of boost on an AAZ. You would likely want a VNT 20 or VNT 25. I am quite sure that if you used one of those you would be replacing connecting rods much, much more frequently than turbos. :wink: I would also mention that EGTs are waaaayyy cooler running a VNT than a wastegated turbo at similar boost or power levels. We haven't been able to get above 900°F pre-turbine on my friend's quantum despite trying an extended run on a highway 6% grade. From a stop at the bottom of the hill we were going 80+ MPH before it got above 900°F. We also can't seem to keep the boost below 20 psi with an intercooled VNT17 on a 1.6TD and boost is any time you want it.
Andrew
i suspect that you are correct about sizing being the problem...
anyone running a vw with a t3 will always say that t3's are indestructible - because they don't work very hard for their whole lifetime! a t3 is a big turbo - much bigger than really needed for a 1.6 or 1.9 - hence, max rpms are seldom reached, the turbo goes forever.
likewise, vnt's are probably contructed better than any older turbo's, but die to the sizing, they do run crazy rpms. this has a shortening effect on the life of bearings etc, and the longer your turbo runs at max revs (which is the goal of a vnt) then the faster you can expect it to wear, and possible fail.
even the k14 is (from a traditional persective) a little large for a 1.6 - but perfect in real driving terms.
i don't think from any performance perspective that a vnt could fall behind a wastegated turbo - the technology is superior. but the application must be correct. - and since the goal of modern engine production in the tdi area is to burn clean and torquey, then the goal fir the engine producer (vw) is to make as much boost right through the low rpm rev range as possible, yet still be useable up the top end for that kW selling point. thus, you fit a small, highly stressed vnt that if driven hard, will wear out fast.
if, on the other hand, your goal is to make an ever lasting 70hp slogger, that doesnt spool much around town but gives you a hand up the grades on the freeway, then mr vw engineer puts a t3 on a 1.6 IDI and it goes forever and ever and ever.
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#52
by
Vincent Waldon
on 29 Dec, 2007 16:29
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I read somewhere that on some of the new makes of diesels with cats, that the engine would periodicly surge the egt's to burn out any build up of soot etc.
Would an occasional egt spike like this help burn out any build up inside the vnt turbo's?
I've read several places in the last little while that VW themselves are recommending a "spirited" drive at least once a month to degunk the VNT vanes, and I know my local mechanic calls gunked vanes "the grampa syndrome" as in: babying it all the time is actually bad for it.
Somewhere on the Internet there's a fantastic DIY of of a VNT rebuild where the dude laboriously adds that nuclear-grade antiseize to each vane actuator... as I recall he claims they never jam again after he's done with them. Unfortunately I've lost the link....
"Sorry I'm speeding honey... but Volkswagen insists.... " ;-) Think the cops would buy it ??
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#53
by
stewardc
on 29 Dec, 2007 17:46
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I've taken apart many wastegated and VNT turbos and can say that there is nothing more robust about a wastegated turbo. I do however believe the information that there are more turbo problems now with new vehicles than there were in the days wastegated turbos. There are three reasons for this as I see it. One is that the turbo vanes have very little room for movement on the VNT. Any carbon buildup will quickly cause the vanes to stick. The second is that they spin a lot faster and will easily surge under the "right" conditions. In an attempt to eliminate turbo lag, the turbos fitted to most new applications are IMO too small for the engines they are being fitted to. I have a KKK that was fit to a 1.9 TDI that looks like it would fit a chainsaw. I can't fit my thumb in the compressor outlet. The conditions where the turbo will be damaged are then attempted to be controlled by the computer. Any issues with the sensors or control system over any period of time can result in significant damage to the turbo. The final is that there are quite a few "turbo problems" that are actually problems with the sensors or vane control system itself. I think that you would be hard pressed to blow up a VNT unless you ran one that was considerably too small and ran too much boost through it consistently. I also think you would need one of considerable size to hold down consistent levels of 35-40psi of boost on an AAZ. You would likely want a VNT 20 or VNT 25. I am quite sure that if you used one of those you would be replacing connecting rods much, much more frequently than turbos. :wink: I would also mention that EGTs are waaaayyy cooler running a VNT than a wastegated turbo at similar boost or power levels. We haven't been able to get above 900°F pre-turbine on my friend's quantum despite trying an extended run on a highway 6% grade. From a stop at the bottom of the hill we were going 80+ MPH before it got above 900°F. We also can't seem to keep the boost below 20 psi with an intercooled VNT17 on a 1.6TD and boost is any time you want it.
Andrew
i suspect that you are correct about sizing being the problem...
anyone running a vw with a t3 will always say that t3's are indestructible - because they don't work very hard for their whole lifetime! a t3 is a big turbo - much bigger than really needed for a 1.6 or 1.9 - hence, max rpms are seldom reached, the turbo goes forever.
likewise, vnt's are probably contructed better than any older turbo's, but die to the sizing, they do run crazy rpms. this has a shortening effect on the life of bearings etc, and the longer your turbo runs at max revs (which is the goal of a vnt) then the faster you can expect it to wear, and possible fail.
even the k14 is (from a traditional persective) a little large for a 1.6 - but perfect in real driving terms.
i don't think from any performance perspective that a vnt could fall behind a wastegated turbo - the technology is superior. but the application must be correct. - and since the goal of modern engine production in the tdi area is to burn clean and torquey, then the goal fir the engine producer (vw) is to make as much boost right through the low rpm rev range as possible, yet still be useable up the top end for that kW selling point. thus, you fit a small, highly stressed vnt that if driven hard, will wear out fast.
if, on the other hand, your goal is to make an ever lasting 70hp slogger, that doesnt spool much around town but gives you a hand up the grades on the freeway, then mr vw engineer puts a t3 on a 1.6 IDI and it goes forever and ever and ever.
Well spoken (written) my man. Applause to you.
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#54
by
dillenger1
on 30 Dec, 2007 04:59
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how have you moddified the VNT to keep from sticking?
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#55
by
AudiVWguy
on 30 Dec, 2007 19:39
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Can anyone post what the compressor and exhaust sizes are for the T3?
Also, has anyone used a water cooled turbo (from a gasser) in a diesel application? Where do you attache the water cooling hoses to get the flow correct?
As far as the return oil line, what's the minimum I.D. for this? What is the commonly accepted return point? Lower block or upper oil pan? Downsides??
Thanks,
-JB
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#56
by
dillenger1
on 31 Dec, 2007 04:59
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I think theres a thread started about watercooled turbos.I believe someone said that there are some k24 or k26 that have the watercooling jacket.No need for gasser turbo.
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#57
by
AudiVWguy
on 31 Dec, 2007 13:47
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Sorry, I thought we were all trying to bring together knowledge about the subject of turbo-charging. Stuff we've tried, been there-didn't work, I don't think it would hurt to think outside the box and include applications from other areas.
For example, in my situation, I found out that the turbo listed in the old Callaway kit that came with the Caddy I bought is a brand called Roto-Master. I finall found a company to rebuild it and the guy said it was a Garrett. I found out later in the inventory sheet it's called a T04B and had a number by it 104146-C . Markings on the turbo I could find said:
Exhaust A/R .4
Intake A/R 60
There was a number 104395 (on the compressor)
And 104247 (also on the compressor)
Anyway, I was wondering if this is a bigger turbo than a T3? It seems a bit laggy, and you have to throw a lot of fuel at it to really spool up. So maybe this the wrong turbo for this motor.
Or maybe I should look at building a 1.9 :twisted:
Happy New Year!!
Jeff
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#58
by
91MF
on 31 Dec, 2007 14:50
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The preference of turbos vs. superchargers is due to the fact that the added boost from a turbo is "free" energy recovered from exhaust heat (makes the engine 10% more efficient) and, in contrast, the added power produced by a supercharger costs energy by being a direct drag on the engine.
i just started reading this thread but for someone who obviously has technical knowledge involving turbo chargers and VNT control systems etc. your comment stating turbos make engines '10% more efficient' seems silly as even a turbo noob would know the exact efficiency is dependent on much more than just the fact that there is a turbo present. its especially ridiculous considering you are quick to point out others comments as foolish if the technical content is not in line with your opinion.
that said, hi. im relatively new here, as well as to diesels and i just figured i would get my initial jerkface post out of the way. i would also like to say i have enjoyed your thread on the
gt2559v retrofit to your mercedes and it was some good reading for me and the boys at the shop.
j
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#59
by
dillenger1
on 31 Dec, 2007 15:32
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No need to be sorry ,I didnt mean to sound fecisious.I am game for all knowledge.Im not one to scold,Im new to this forum community myself so that being said ,i just wanted to thank everybody for all the knowledge.Every day i get alittle closer to completing my ride
