My harrowing journey through the murky swamps of compressor map interpretation.

[theman53]

those k14 and k24 maps are definitely not for the vw turbos, i would not make your decision based on what you see from those 2 maps.

That is what I said in your other thread about there being several different K14 and K24 turbos. Right now, since I drove the mk2 last night and had fun, I think that the best deal out there are the holset turbos. I talked to the rebuild guy as I am going to get the VNT rebuilt on the TDI and sell the spare, he said the Mitsubishi turbos are very very similar to the holset. Both holset and Mitsubishi come stock with the 360 main bearing and all the others only have it as an option and come with the 270. And because of that I am pretty much going to stick with one of those brands from here on out. That bearing does wonders for spool and the load that we put them through.

[Gizmoman]

Gizmoman; I've been reading your turbo transplant thread...you are doing some good work there....you have way more patience for fabbing than I do.  I'm hoping that pushing the K14 to 20psi will add enough air to let me make some long pulls through the hill without making molten aluminum.  Time will tell.

Thanks for the chinup. As for the K-14 at 20 PSI, I can't say with any certainty but if I don't account for the .32 diameter restrictions in my previous drain line, I'd have to say that not only will you stop pushing any air past 18, you may also find oil in your intake (and IC as well). Possibly someone else can chime in on running a K-14 at 20 psi for extended periods but personally, I wouldn't.

Your eye on the EGT gauge (with a fast acting sensor) should keep you from melting down. We all have personal limits and I finally set mine at 18 (still not enough air to keep EGT's under 1300 based on the Giles IP fueling and DIY IC coated with hot oil).

FWIW, I rebuilt  the K-14 myself, was very meticulous, and installed a new 360 bearing as well. I don't recall a seal on the compressor side and believe the manufacturer had designed it for 10 PSI max. In other words, this turbo is tough but it's also limited. Even before the rebuilt Giles IP (stock IP fuel screw turned in 1/2 turn), I was running 15 psi and no EGT sensor or IC at all. The van ran at 15 PSI on nearly any grade above 2% and I watched the temp gauge climb often well past the center (it's happy place) till I gave in, downshifted, and moved in behind the big rigs. One day, I just said F-it, pulled into lane two, and pushed it to the floor - big mistake.

[JoeCanuck]

That's interesting....I didn't know you went past 15psi with your 14....or I just missed it.  Have you done any driving with your new setup yet?

A few nights ago, I was checking out Utube....and there were a few aaz/k24 videos....and I was surprised at how quickly the K24's did spool.  My caution about going to a bigger turbo comes from my dodge cummins.  I have an Holset hX35, which was originally waste gated to 22psi.  I changed the injectors, disabled the wastegate and chipped the truck and it will climb crazy hills at 30psi, and keep my temps below 1200.  Many warned me that anything over 25psi is just pumping heat but under loads, I have spent significant time at 35psi...and never had egt's hit 1300.  It's a great middle of the road turbo for my truck.....pretty fast spooling and more than enough top end for me.

I believe the K14 and K24 can fit on the same manifold so it shouldn't be a huge deal swapping one for the other....but you did have a extra fresh K14...and a Westy is about twice the machine of a Jetta...so now I'm leaning again towards the K24.

In the long run, I'd like to try a variable vane turbo...but I have 4 turbos at home to play with....a K03, 2x K14, and a K24....and it's hard to beat free...at least at first. 

It'll be a few weeks before I get time to tear into the project, but I"m getting quite excited about it....now if only bloody spring would come. 

I'm very disappointed with all this global warming I've been promised. 

[RabbitJockey]

That's interesting....I didn't know you went past 15psi with your 14....or I just missed it.  Have you done any driving with your new setup yet?

A few nights ago, I was checking out Utube....and there were a few aaz/k24 videos....and I was surprised at how quickly the K24's did spool.  My caution about going to a bigger turbo comes from my dodge cummins.  I have an Holset hX35, which was originally waste gated to 22psi.  I changed the injectors, disabled the wastegate and chipped the truck and it will climb crazy hills at 30psi, and keep my temps below 1200.  Many warned me that anything over 25psi is just pumping heat but under loads, I have spent significant time at 35psi...and never had egt's hit 1300.  It's a great middle of the road turbo for my truck.....pretty fast spooling and more than enough top end for me.

I believe the K14 and K24 can fit on the same manifold so it shouldn't be a huge deal swapping one for the other....but you did have a extra fresh K14...and a Westy is about twice the machine of a Jetta...so now I'm leaning again towards the K24.

In the long run, I'd like to try a variable vane turbo...but I have 4 turbos at home to play with....a K03, 2x K14, and a K24....and it's hard to beat free...at least at first. 

It'll be a few weeks before I get time to tear into the project, but I"m getting quite excited about it....now if only bloody spring would come. 

I'm very disappointed with all this global warming I've been promised. 

i'd use the k24 out of those choices, once you crank up the fueling a little and adjust the wastegate/add a mbc they spool very well, k24 is really not at all a large turbo.

[vanbcguy]

My K24 was great on my 1.6TD the whole time I had it.  I was running at 24 PSI for the last 3 years or so with no issues besides eating my transmission.

[Gizmoman]

95% of the time I had the K-14 at 15 max so that's generally what I tell folks I had it set to. I only turned it up to 18 just before I found out it was pissing oil into my WAIC. I didn't put many miles on it at 18 but noticed little to no dif in that short time - EGT's were still easily hitting 1300+.

General logic may tell you that adding boost should keep oil out of the compressor but my thoughts are that it's basically a pump - and when they turn faster than design it creates cavitation, and all sorts of ugly things begin to happen rather quickly - possibly even creating vacuum from imploding balls of air molecules (put that in your pipe and smoke it). However, I could be totally wrong

I just spent a year and a lot of bucks rebuilding the engine and every 1300 hit really made me wince - turning up the boost to 18 already had me worried. When I saw that it did little to lower temps, I stopped right there and ordered the Holset. Again, there may have been several other factors involved but it takes more air and stock fuel to make more HP/torque and still keep the temps down. That said, I agree with the K-24 route.

I finally have most of the bits I need to pipe it up this weekend. A new bottle of Argon mix for the tig welder and it may actually run this weekend (or not).

[theman53]

I had a K24 and a couple different setups of the T3 hybrid in my 2nd round build thread and I went to the big brother Holset of Gizmo's The HE221w. The second T3 hybrid I did was a 360 main bearing and a counter threaded shaft so that the shaft turning backwards wouldn't loosen the nut like the first...so it broke the shaft. The bigger the turbo the better IMHO. From what I have been reading and listening to the Holset and Mitsubishi turbos are all I will use in a performance setup from now on.

If I were you I would rebuild the K24 with a 360 main bearing and run that...if you don't get a Mit or holset

[Syncroincity]

Some nice explanations of Trim and A/R numbers here;

http://www.turbobygarrett.com/turbobygarrett/turbine_housing_AR_and_housing_sizing

[JoeCanuck]

I am pleased that there are so many good responses to this thread.  Every little bit of information helps build the big picture.

Gizmoman;  good luck on getting the beastie running....I look forward to the details.

Syncronicity;  that's a very good site...thanks.