1.6TD k24 or T3 on AHU?

[the4ork]

just looking at options here, the compressor maps well out perform the gt15. I just got my motor out of the car and can now see how PUNY that thing is. its almost sad looking.

thinking about picking up a used t3 or k24 1.6td kit and some .216 nozzles and calling it good.

[bbob203]

I've heard k24 turbo with ..216 nozzles and rover pump on an ahu will make serious power.

[xxkoadyxx]

i have a k14 on mine. not sure how it works cause car was just started yesterday for the first time in 8months

[8v-of-fury]

Honestly if you look at the maps of the 35 trim vw T3 compared to that of the GT15 or identical K03...

http://www.vwdiesel.net/forum/index.php?topic=25420.msg308404#msg308404

The compressor wheel on the 35 trim T3 is nearly as small as the compressor on the GT15/K03, so I would not choose it for that reason.

The K24 however.. does quite a bit better than the 35 trim T3.

[the4ork]

thats a good point...

i was planning on (if i get an older mk1/2 unit) having the core shipped directly to the rebuild sponsor and... (this is the part i havent researched yet and you can add in put) see about getting the compressor upgraded to a larger wheel, to mimic a 50 trim T3?

im pretty sure this is possible but not sure if the turbo builder would do it.

Im also guessing this would be easier to source parts for than finding a larger wheel for the k24, although perhaps a k26 wheel would work.

Going this route yields me a brand spanking new looking/operating snail with a nice bump in power.

[8v-of-fury]

Ahh now that is a good idea!

I am not up to snuff on what swaps between what in terms of wheels and housings.. unfortunately I am just getting in to really understanding them fully down to trims, wheels and A/R stuff.

[the4ork]

well all the exducers are the same size, 2.367 or ~60mm, but the exducers (the smaller fins) are whats different on all T3 compressor wheels unless you go to a completely custom compressor wheel.

the problem with that is finding/matching a compressor housing which inlet is sized correctly for the inducer (as to not have too much gap or interfere)

So the cool thing is all T3 stuff is interchangeable. you can take the 35 trim wheel (gayyyy) and put in a 40, 45, 50, 55 or 60 wheel in there. Now they are all the same size, but the small fins are all sized differently.
After swapping the wheel, you just need the appropriate compressor housing. Turbonetics stuff is really easy to mix/match because there are plenty of retailers online that sell wheels and housings brand new.

the turbo rebuild sponsor also carries billet compressor wheels. after a quick search on his website i couldnt find any for a T3 but he has cool stuff on there like billet compressor wheels (lighter=faster spool + stronger) BUT no T3 wheels. found a t28 wheel which is similar but its more of a 60 trim size. same exducer but a large inducer.

here is some sizing:

Wheel Trim: 35
Inducer: 1.396"
Major: 2.367"

Wheel Trim: 50
Inducer: 1.674"
Major: 2.367"

Wheel Trim: 55
Inducer: 1.760"
Major: 2.367"

Wheel Trim: 60
Inducer: 1.830"
Major: 2.367"

Billet T28 wheel:
Wheel Trim: 60
Inducer: 1.831"
Major: 2.367

If it were closer to the 55trim i'd say pull the trigger and throw the T28 billet in there, but im afraid it will be too large

you could attempt to swap it out yourself by buying a turbonetics compressor wheel. not sure if they are interchangeable with garrett, they should be? or maybe you could source a chinese one just for testing purposes.
http://www.ocdiesel.com/Turbonetics-20268T-T-Series-Compressor-Wheel-p/tn-20268t.htm

[the4ork]

actually after a quick compressor map and calculation it wouldnt be too bad to have a 60trim. THAT said, if you use the T28 BILLET wheel (assuming its possible, perhaps the shaft size is different) you get a smaller hub (more fin surface area, more cfm, more power), and lighter weight (faster spool) so what the hell why not?

[8v-of-fury]

Ay' but what of the turbine side? Clearly the 1.6 T3 exhaust housing is limited after a certain point.

Would you be able to move enough air out to fully utilize a 60 trim pulling in?

[the4ork]

thats a good question, surely at 200hp, or by some point the turbine would be restrictive.

but remember 1.8t's are 20v vs 8v and spin 7k rpm and make 180hp (and also the 225hp engine) with a tiny k03s with a much smaller turbine wheel and a/r. they are surely flowing more than double out the exhaust. Im not sure if the increased compression adds to flow, my initial logic points to no... its roughly similar bore and stroke so cfm out of the cylinder should be similar as well.

food for thought, but i doubt a tdi would be restricted by such a turbo.

[8v-of-fury]

This has been a most informative thread. Thank-you.

I wouldn't think the increased compression would affect CFM, and the 225hp on a k03s is a good backup of the T3 likely being alright turbine wise.

So upgrading the 35 trim wheel to whatever size you choose, would also require a change of the compressor housing correct?

[CRSMP5]

talk to theman.. the local turbo guy did cold side mod for him..

[the4ork]

yes all you would have to change is the wheel and its matched housing

each wheel has its own housing based on inducer size.

[the4ork]

This has been a most informative thread. Thank-you.

I wouldn't think the increased compression would affect CFM,

i think this is an accurate statement though ive never exclusively researched it. but increasing the compression only increases pressure, not volume so cfm should remain the same or similar

[CrazyAndy]

As far as compressor wheel interchangeability, have you considered some used alternatives?  What I mean is scouring the junkyard for '80s turbo Saabs and Volvos and scavenging their turbos to use their compressor wheels and housings.  The 16-valve Saab models after '91 IIRC have 45 Trim cold sides, and D24t Volvos up to '87 have 50 trim housings.  The biggest problem is finding them, but if you can either via junkyard or eBay you can get your upgrade for cheaper.  Failing that, try contacting a turbo builder and parts provider like Majestic Turbo (they had a 50 trim T3 housing and wheel last time I checked with them 3 weeks ago) in Waco.  That's the route I'm going with my own T3, as the local yards don't really have anything bast 1995.  Hope this helps.