TheAllusionist

K26-6 to K27-8ish Family Turbocharger Upgrades:

I am very excited! I have been putting together the parts for a stealth build for my 1986 944T that has low original miles so that it doesn't look raced or "Ridden hard and put away wet"! My Build Thread

A few months ago I had Charlie at Evergreen Turbo build me a K27-8 because it would look close to stock and the average porsche guy probably couldn't tell that it wasn't stock and yet boost my power. Simple enough, then since I needed to replace my head gasket and already had a lot of performance parts, I started slipping down that slippery slope, next thing you know I had a hi flowing head and modified intake, and...... Now I was second guessing the K27-8 I had built and started researching the heck out other options such as the Holset HX35 that Tim Scott offers and was strongly considering dropping the coin to purchase one of those. Then I decided to contact Charlie at Evergreen Turbo as he already had gotten business from me, hopefully he wouldn't mind me getting his input on newer technology versus the turbo he built for me. So I sent him and email and get one back shortly asking if he could call me in 30 minuts, and I say Sure!

In the mean time I get this email with some pictures and information:
"Look at this new design K26/7 high flow turbine and billet upgrade we are now building. This turbo hits hard in the 2700 range with a 8 housing and will produce in the 450 plus range. This is also a bolt in which is even better..has a 360 thrust set like your #8 does also. Twin seals which no other turbo has. On the turbo I built for you we can change things and this is great setup that we just finished setups last month."



So it turns out that they are now set up to mill out the housing and install a billet compressor and turbine into it, there is a lot of porting and other work going on, this isn't my area of expertise so I am paraphrasing things at times, but in the end he is getting a lot more flow and fast spool up times with less back pressure. This is what he is saying, once I am done some dyno time will tell the tale, but Charlie is highly recommended and he put up with me pestering him for years before he got my business. I have no vested interest in this turbo, I am just excited that there is a bolt on option that allows us to alleviate some of the limitations of our K series turbos and use modern turbo design. Maybe I am getting all excited about nothing, but my turbo was boxed up today and being sent back to Charlie for these upgrades.

So Charlie calls me and tries to explain things to me and my poor mental comprehension level only gleamed a small portion of the information he was bestowing. The part that really sunk in is that Charlie said something about since he just built my turbo for me and this is now an option he would make the mods to my turbo for a great deal, I won't go into the deal but I think he is being very generous. So now it looks like I get my power fix and I plan on starting on tearing into my engne this weekend.

As stated I am not knowledgeable in turbo charging but I have don't a huge amount of research and reading and this sounds like great news for those of us who want to keep our K26-6 to K27-8ish turbochargers, It sounded like the build is performing very well on 930s and their K27s. A high performance fuel pump and the last peice of my exhaust is the last parts to my intended build, did I say how excited I am? LOL

This community is very coo,l people like Charlie and John Vitesse have been very patient with me and helped out tremendously as well as numerous other members on this forum. Big thanks to everyone on that.

TheAllusionist

'These are K26 compressor with billet comp wheel and the cover upgrade images that Charlie sent me.

Chapman951

TheAllusionist

I shipped my turbo back to Charlie on my way home, can't wait to see how it performs. I just thought it was very cool to see this for our stock turbos.

TheAllusionist

Some further correspondence with Charlie:
" One thing I want to point out about how these turbos are matched building them to make up to 490 HP @ a reasonable boost level (17 -18) The goal to make more than 490 would rather see a larger turbine housing like say a #10 but they only exist in a rectangular flange from Turboladder. These turbos are built to put a durable very responsive turbo making between 350 to 490 HP depending on the #6 or #8. The large high flow turbine drops the back pressure considerably and waiting on the numbers from our RD Test Turbo." "Not sure you noticed in the pics the flange is resurfaced also. Usually take about .005 to clean it up.

Then the machining begins to open the pilot area then the profile machined."



" Pilot area & profile machined for CHRA vs stocker "



Time will tell what the performance gains will be with this turbo, and I can't wait to find out, it is fun to get excited about something and this one made my week!

TheAllusionist

Happiness is hearing that your new turbo build is completed! Charles send me pictures today of my latest turbo build completed. The previous pictures in this thread would show where the dramatic work is performed, but these comparisons of the build he did a few months ago for me versus the build he just did for me definitely shows the difference in the turbine and the compressor. Now if only my head build was complete!




Excited to get the build complete and see how this performs!

fasteddie313

Is he replacing the whole CHRA or just installing new wheels?
Same bearing housing?

TheAllusionist

I do not know, look at the size increase in the pilot? area, I don't know if that requires a different center section. I could always ask him.

steven74

I would be interested to see how this turbo compares to the new voodoo turbo from Tim's turbos. They both seem to be along the same thinks of adapted newer technology to the traditional exhaust housing packaging to be a direct bolt on alternative. A member of the Texas 944 Facebook page reported 400rwhp on a completely stock 2.5l long block. Your turbo sure looks promising as well.

TheAllusionist

I was looking at one of the Holset units Tim's Turbo was offering, but then Charlie gave me a heck of a deal as I had been asking about porting things out and newer design turbines, etc. and at the time he was only able to source billet compressors, so when he shortly after started making this new Hi-Flow turbo he made it up to me. One can conjecture all you want and the old timers probably laugh to themselves when something like this cycles around and say to themselves, been there, done that! But can't help but think it will be a big improvment. Until my build gets done and I get it on the Dyno, it is speculation on my part.

I saw the FaceBook post about the car you are talking about, gives me encouragement as I will have a lot of performance parts matched to the new turbo, so hope that the combination of it with high flowing head, intake, modified inercooler, large exchaust, Viteasse MAF..... will really bring things to life and I can run moderate boost with good HP.

Good or bad, when the time comes, I will post the Dyno charts, my original goal was 340-350 RWHP, if I got to 400+ RWHP, I would be pretty estatic! LOL I know it would be on racing fuel and be one Dyno Queen like run, then turn down the boost and tune for on the street.

TheAllusionist

At the risk of sounding like a paid advertisement for Evergreen Turbo, here is some of my conversation with Charlie, some of it to address questions/comments here:

Q: Is he replacing the whole CHRA or just installing new wheels? Same bearing housing?

A: Yes I am, depending on build will replace the turbine wheel and comp wheel using your existing core. I build the turbos around the KKK platform for bolt in set up on oil lines and exhaust bolt it direct. Compressor cover if larger K27 will need inlet change with water temp sensor pipe lengthened. On the Bearing Housing it is not left as is, it is Line Bored for plus .005 Sintered Bronze Bearings so the specs are perfect. Same for the Bearing Housing Seal Area. If they need machining will open up for plus .010 Seals

Q: I would be interested to see how this turbo compares to the new voodoo turbo from Tim's turbos. They both seem to be along the same thinks of adapted newer technology to the traditional exhaust housing packaging to be a direct bolt on alternative. A member of the Texas 944 Facebook page reported 400rwhp on a completely stock 2.5l long block. Your turbo sure looks promising as well.

A: Several of these are out there on 2.5s for testing and sold many running also. The 2.5 will produce that 400 hp but it also will hit boost in the 2600 RPM range compared to stocker hitting low 3k. That is with much larger turbine compressor wheels.

On the boost response...many I think you have found out that bought bigger turbos for the 400 hp area and up have horrible boost response with the heavy Garrett or Holset Turbine Wheels. They produce good hp but I get a lot of how you can make the turbo boost faster, this is why I designed this 9-blade turbine around the KKK turbine housing.

Here is why I ask to use your original core. The KKK Line they do not sell piece parts i.e. turbine housings or bearing housings etc. When we have the machining equipment here to machine the turbo and blueprint specs in over under sizes this save the customer lot of money. Could buy new turbos and strip them if a customer wants to spend that extra money but the KKK turbos are pretty pricy to do that.

General Discussion:There are stock turbine upgrades with bigger compressor wheels and also bigger compressor housing and compressor wheels. Also, the # 6 or 8's can be machined for the larger 9 blade high flow turbine wheels you can see pictures of. There are many variations for build from the #6 with small billet K26 billet making 280 hp up to the big turbine billet compressors all the up to 450hp on a fully modified #8 turbo.




Here is the 944 stock K26 comp cover upgraded with a billet compressor for up to 300hp level


: K27 Billet Comp section


#6 or #8 Turbine Housings machined for much larger 9 blade high flow turbine


Bearing Housing line bored


Ported Turbine Housing for the K26 frame to increase flow and shorten the diffuser also to increase flow.


Flange is resurfaced when necessary then profiled for larger 9 blade light weight turbine wheel, the key to fast boost response in the 2000k RPM range.
The larger 9 blade high flow turbine wheel gets rid of a lot of back pressure with porting this should not be a issue. Many k26/27s old school with standard clipped #6 turbine with K27 compressor ran great and produced good power in the lower to mid 300s. They did have more back pressure then you like to see but the cars responded to them very well.

All I can say is I am looking forward to getting my car going and seeing what kind of performance I get!

Droops83

Cool, thanks for sharing. Charlie built me the same but with a #6 housing (as posted elsewhere on this forum), as we couldn't find a good used #8 housing at the time, and we wanted to see how fast the thing would spool . . . . mine builds meaningful boost at 2000 RPM and 1 bar by 3000, so I'd say it works!

I am worried about excessive back pressure with the small #6 housing, however. Charlie ported out the throat of the turbine housing as much as possible, but I'll be checking back pressure once I get my car out of the body shop and I will post results on my thread.

The Voodoo turbos also look like a great option. It is nice to see reputable turbo companies offering modern, reasonably-priced components for our old cars that are also bolt-on!

TheAllusionist

Whole heartedly AGREE!

fasteddie313

The turbine upgrade in the original turbine housing and bearing housing is very interesting to me because the dimensions are critical for my 931 unless you want to make custom exhaust everything..

The turbine upgrade in specific. The claim is faster spool and reduced top end backpressure changing to their turbine alone?

I think I'll have to do one more turbo some day after I max out the #8hot/#6cold in 931 housings contraption that I built and am using now..

I have #6 core minus the compressor parts if anyone wants them for a build like this..
I might have a spare oil cooled only bearing housing with bolt-up lines and mounting dimensions for 951s if someone really wanted one of those for a build like this, no water ports, oil cooled design..
Some audi k26 parts, both types of 931 compressor housings and just a whole big drawer full of k26 turbo parts...

I think a #8 compressor done with a billet wheel would be good place to stop at for me..
I have my eye out for a #8 compressor housing, backplate, and wheel for my next turbo build.. Their have to be takeoffs out there from people swapping to k27 compressors..
That along with this turbine upgrade sounds like a good final combo..

Oh oh..
Can we get compressor maps of these billet comp wheels? If your guy has them?
For the billet wheels available to replace the 2670, 2667, and 2664 k26 compressors?

They say good for xxx HP but I'm higher in the maps for the same power with my 2.0..

TheAllusionist

I would suggest contacting Charlie at Evergreen Turbo with questions, I don't have that information and still trying to get some free time to complete my build. Sounds like you have a fun project yourself.

Regards,

Russell