Who has done a k24/k26 and are completely thrilled with the results?

[saurkraut]

I've done it, and the results are lack luster.  As a matter of fact, I'll call it down right horse-it

Granted, its on my 1.6TDblock/1.9head project, so there are other variables in play.

The Build: http://www.vwdiesel.net/forum/index.php?topic=15780.0

But I'm getting high EGTs with the same pump that I had on the same engine that used to have a 1.6 mechanical head.  And that would only touch 1300º F occaisionally.

The boost seems to build a little slower, but the EGT shoots up past 1300º F as the boost climbs to about 25 PSI.

I rotated the boost pin back to a lower slope, and put the plastic collar back in, and its a little better, but I wouldn't run it through all five gears full throttle as it will probably go past 1500º F.

Pump timing is set at 1.04, injector break pressure is set at the upper limit.  2.5" exhaust, turbo to rear bumper.  No intercooler.

I'm wondering if the K26 compressor doesn't like to make that much boost?

[Smokey Eddy]

Hmmm. I have an identical build with a T3 and i never hit 1300... 1200 is like a max with mine. the only difference is im using an intake off the TDI ALH engine and my head is hydrualic. It will get to 25 very quickly. Did you port or polish your manifolds or head?
I have no clue what my timing is set to or injector pressures. i have 2.5 inch from the turbo back to the rear tires where it splits to dual 2.5.

My high egt times are usually when the rpm is too low.

oh, PS. what advantage is it to remove the plastic collar? should i remove mine? more fuel on boost?

[saurkraut]

The k26 compressor i used was off of a Audi 5000.  I got a feeling this compressor flows really good at 10PSi then falls on its face.

I noticed the other folks who have made k24/k26 hybrids don't seem to share there observations.

Maybe that says volumes right there.

Oh, I polished the heck out of everthing, matched the ports to the manifolds, ported the head useing the david vizard article.  It should go like a scalded cat, but the EGT is spiking rapidly.

I'll test it a little more, then yank it off the car and put it back to a standard K24.

[lord_verminaard]

Which flavor k26 is the compressor from?  You're right though, any version of K26 that I have seen a map for is WAY out of it's efficiency range at 25 psi.

Brendan

[saurkraut]

Which flavor k26 is the compressor from?  You're right though, any version of K26 that I have seen a map for is WAY out of it's efficiency range at 25 psi.

Brendan

Kind of begs the question, why even do it?  The stock K24 does well up to 25 PSI

The compressor is out of an Audi 5000 turbo quatro (gas motor).

Well, I geuss I'll take it off, and put it back to a proper K24.

Should be in the FAQ,  do you have any data you can post?

[lord_verminaard]

I'll throw up a few quick calcs.  After a quick google search, i can't seem to find which flavor of K26 the Audi 5000 had, I'm sure I could find it if I dug a little deeper, but these are the ones available up on squirrel performance's turbo calculator.

For reference, this is a 1.6L running about 25psi.

K26-1


K26-2


K26-2470R


K26-2664G


None of the K26's really are suited for that kind of boost pressure.

Brendan

[saurkraut]

The last one is probably it; Audi 100, K26-2664G.

Screw it, I'm not going to run it with that compressor any more.

Off she comes.....

Thanks for the info!

[Rabbit on Roids]

ship that bad boy over to me for a few days, let me see how it works on my 5000. i want to build one, but if you say its not worth it, then its not worth it. the biggest thing with the K26 tho, it flows alot better than the K24, it may not make more boost, but it has alot more air going through it at a set boost pressure than the K24 does.

[53 willys]

I hated my k24/26..... While I did not have any egt issues(I'm intercooled) but the lag was pretty bad and not really a useable rpm range for dding

[Rabbit on Roids]

so, should i just keep my K24 on my audi like it is? i just made a boost controller yesterday, and set it to about 18 psi in the shop, but havent put it on yet. whats the upper limit for these? like 25 psi or something? whats safe? 20 psi?

[lord_verminaard]

K26 on an Audi 2.0 TD @ 18psi (sea level, intercooled):



Not great. 

Brendan

[Rabbit on Roids]

k24 is better suited to the engine? i dont really know how to read turbo maps that well either.

[saurkraut]

ship that bad boy over to me for a few days, let me see how it works on my 5000. i want to build one, but if you say its not worth it, then its not worth it. the biggest thing with the K26 tho, it flows alot better than the K24, it may not make more boost, but it has alot more air going through it at a set boost pressure than the K24 does.

Sorry, no dice.  I'll need the K24 hot side and bearing housing to reassemble into a full K24 for my 1.6/1.9 project, and the K26 stuff i'll keep for my '86 TQW.

[saurkraut]

I guess the issue is how the compressor works at a specfic boost pressure.

Since I haven't gotten around to installing an intercooler, we have a more or less direct comparison of the two compressors.

From my experiment, it can be seen that at 25 PSI, the K24 compressor does a better job than the K26 compressor.  They both get to 25 PSI, but the k26 is heating the charge air a heck of allot more than the k24.

I wonder if it opposite at 10PSI?

I wonder if there is another K24 compressor that does a little better at 25 PSI?

[Rabbit on Roids]

is it safe to run a K24 with the wastegate set at about 25psi with a wastegate still hooked up and boost controlled?