Garrett GT2056 turbo

[vanagonturbo]

3900

[Alcaid]

Surge at 3800rpm/16psi before and now 3900rpm/18-20psi. Does it give that much more boost now with only 100rpms extra?

[vanagonturbo]

Well, I did change the cam out. So maybe thats it? Still kinda sucks as I am about 10psi below what the goal was. Ive been looking at a 2052-3 lately but from what I am seeing is that higher up inthe RPM range (5300-) its past the choke line. Perhaps I am entering the wrong criteria? I have been using http://www.squirrelpf.com/turbocalc/ for plotting.

[Alcaid]

Volumetric efficiency has improved since changing the cam, from 65% to 70% now. Is it a DIY porting job? A GT2056 could work better, but with a lower trim than the 55 trim compressor you have now. The GTB2056VL that Volvo and Alfa Romeo uses has a 50 trim wheel, but they are both VNT. Or the other option is to increase your VE, better porting, bigger valves maybe, better seat cuts, better camshaft etc.

[RabbitJockey]

when i use squirrel i do 18-22:1 a/f ratio with a .36 bfsc, i usually put the ve down to 85 for all rpms, and this seems to match daves dyno with the turbo he used so i figure it must be somewhat accurate

and when i do a 1.6 with gt2056 i get surging around 22 psi, so not too far off from what u have.

[Alcaid]

when i use squirrel i do 18:1 a/f ratio with a .36 bfsc, i usually put the ve down to 85 for all rpms, and this seems to match daves dyno with the turbo he used so i figure it must be somewhat accurate haha

VE=85% is pretty optimistic for an 8V, even a good ported Franken one.

vanagonturbo's example over here proves a VE around 70% in the region of 4000rpm

[RabbitJockey]

http://www.vwdiesel.net/forum/index.php?topic=8073.0


thread about surge and it shows daves old compressor housing

[vanagonturbo]

Volumetric efficiency has improved since changing the cam, from 65% to 70% now. Is it a DIY porting job? A GT2056 could work better, but with a lower trim than the 55 trim compressor you have now. The GTB2056VL that Volvo and Alfa Romeo uses has a 50 trim wheel, but they are both VNT. Or the other option is to increase your VE, better porting, bigger valves maybe, better seat cuts, better camshaft etc.

It is a DIY porting job. I mostly gasket matched and opened it up a bit. I didnt get too crazy because I have heard horror stories of going too deep and ruining the head. Perhaps a PD150 intake might be in order. I cant really fit a gasser intake on there due to clearance with the turbo. Although you mention the 50trim being VNT, doesnt that only affect the turbine side? Does the 50 trim work on this turbo? I think the Jeep uses the same VTN 2056 also. I would like to avoid taking the motor apart again... Just looking for a good solution here.

Thanks for all the input. Sorry to hijack the thread, but I hope its rather relevant as I have no actual info on this forum regarding this turbo using the search...

[vanagonturbo]

http://www.vwdiesel.net/forum/index.php?topic=8073.0


thread about surge and it shows daves old compressor housing

Assuming Dave is hillfolk'er? After reading that thread, it sounds like he just kept it in surge until the shaft snapped and spit the turbine wheel. Is that DP actually as thin as it looks in the pic??

[RabbitJockey]

no daves compressor housing is the one that was drilled out for surge protection, he built a 190whp mk2 jetta with 1.6 bottom and 1.9 head.  with a 50 trim to4e/t3 turbine, dave also had major surge issues which he resolved by just drilling those holes.  hillfolk actually did the opposite, he has a tdi-m that he would run 1.6td t3 and k24 turbos on, and hed run them way past the choke limit at over 40 psi with very high egt temps.

[vanagonturbo]

Interesting. They probably dont make an antisurge housing for the 2056 huh? I am a little hesitant to start drilling holes in the compressor housing. How would one go about determining how many holes and what diameter?

Why did hillfolk run those turbos like that? Doesnt even the T3 go out of efficiency range around 23psi?

[RabbitJockey]

hillfolk did it because it worked ... haha and its what he had laying around.  later he switched to an hx35 with an hx30 exhaust housing which was too big then went with the t3 off of a mb turbo diesel. all this on a flipped rabbit dual outlet manifold with a custom made t3 turbo adaptor.

[RabbitJockey]

i am still wondering if surge is still the issue, malone ran a gt20, and i went back and was reading over his posts regarding the build, he was hitting 20psi at 2k, i haven't found any posts about surge yet, but he did have a pd150intake

[vanagonturbo]

Well, from Garretts website, there are 4 different GT20s. the maps are pretty radically different between the 2056 and say teh 2052-2. I have messaged Malone on here and on Vortex, but he has not replied. I just asked him what turbo he had. I read a lot about his build, so I thought it would be a good turbo. Granted, I dont have the PD intake but is it possible that just an intake manifold could make that much of a difference?

I have been driving it for the past couple of days and it drives ok. Really smooth powerband. I just watch to make sure I dont get to 18psi... Just while the GTD is under the knife getting the trans rebuild and diff upgrade.

[RabbitJockey]

i know it was from the upsolute stage 3 kit but i don't know which one that kit had haha