Techno Duck

First off, please forgive any ignorance because i am not well versed on turbo charged cars. This is my first one (and i love it). Anyhow the car is a '88 951.. NOT a Turbo S. I was going through the records and sometime around 2003 the stock K26/6 Turbo was removed and rebuilt and according to the invoice 'upgraded'. I talked to the PO who had the work done and he said it was sent to a company in the midwest who rebuilt it and upgraded it.

Hes not sure what was upgraded on it specifically, but he stated 'possibly the cold or hot side was upgraded' (though he is really unsure). So out of the K26/8 or maybe a K27 variant Turbo's, which is more likely to have been done? Is it possible to rebuild and modify a K26/6 to a k26/8 easily? Ive read the K26 can be modified to K27 specs (is K26 cheater the proper term here?). Is there any visual way i can tell with the turbo still on the car? I havent driven the car much but it is pretty quick. Only the stock boost gauge... reads about 1.5 - 1.70 bar when on it in 4th. I didnt really check to see if boost bleeds off or not at high RPM. Full 3-inch SFR exhaust, no cat, Autothority chips, Lindsay boost enhancer are the only mods.

The car will be off the road for a few months and in that time was going to be installing a proper boost gauge, wide-band, Vitesse chips and a proper boost controller (probably the Lindsay black ****). I just dont know what turbo i should tell Vitesse i have! The reading on the stock boost gauge seems pretty darn high.. so its partially the reason i want to go with Vitesse chips.

I am going to stop in at the shop that did the turbo work (they serviced the car over a 5 year period) and hopefully they may have an idea of what they had upgraded on it.

Laust Pedersen

For K26-6 vs. K26-8 identification go to http://www.clarks-garage.com/shop-manual/eng-19.htm

Techno Duck

Thank you Laust, i should have known Clark's had a good reference for this sort of thing .

Regarding those rebuilt K26's into K27's.. would a modified K26 (put to K27 specs) still have that flat portion?

944CS

can you see the three k's that make a triangle on the cold side?

caster951

I believe a k27 has a bigger turbo inlet, so the jboot/pipe should be larger than a k26.

Techno Duck

Ill take a close look at everything tomorrow afternoon and report back. I appreciate all of your input so far.

The car still has the stock airbox and AFM, i will check the intake boot to see if its been modified at all.

Keithr726

Take a pic with a flash light on the drivers side of the intake manifold. Also add a photo of this new beast. Welcome to the turbo board, most of us have evolved from NAdom.

Naplesguy06

The K27 has a 3/4 larger opening for the J boot, I believe its 2-3/4" and the 26 is 2". Also inside the hotside inlet is a number, usually that identidies the size of the hotside.

schwank

Uh-oh... Jon got a turbo! I picked mine up a few months back, and after a month in Germany staring at all the Porsches, I can't wait to get home and finish it up and get it back on the road!

Give us some pics Jon... and welcome back to the States!

Techno Duck

Hey guys, i took a better look at the car today. I could defenetley make out the 1-inch square flat spot on the hotside of the turbo. So i am wondering, if a stock K26/6 was modified to be a K27/6, would that flat spot still be present? Also would the stock intake boot connect to the inlet or would it not fit? It appears as if the stock boot fits perfectly onto the turbo inlet. So im really not sure what they meant by 'upgraded' on the old records, but atleast i ruled out it being a K26/8.

If i were to remove the airbox, AFM and intake boot.. will i be able to visually identify it being a K26/6 or K27/6? Anyhow i have a feeling its a stock K26/6. When i get the time i am going to swing by the shop that did the work and ask if they remember what was done to it.

The only issue with the car as of right now (other than the unknown turbo) is it has a broken exhaust stud. The 3rd stud from the front of the motor snapped off flush with the block. The leak isnt bad at all, but i am debating right now leaving it alone.. or taking the head off, Cometic headgasket, Lindsay steam vent kit and redoing all the vacuum lines and hoses. May also try to use a right angle drill on it. Still trying to make the final decision.

Also the fact the car has an unknown turbo, Autothroity chips, no boost gauge and no wideband makes me a little iffy about driving it. I am going to be ordering a Innovative wideband soon and going to look around for a boost gauge that suits my liking. The Defi gauges are very attractive..

Said flat spot on hotside..


It was a crap shoot trying to get a picture of the intake side..




Broken exhaust stud..


And the car..








I am really looking forward to this car.. its nicely setup for track use. To sum it up, i dont have the desire to swap any of the suspension stuff on my n/a. Well maybe the KLA mono ball strut mounts and adjustable sway bar droplinks, but thats about it.

And yes the Porsche reflector on the back will be removed.. the car will soon be sporting a euro rear bumper and all of the 968 goodies (handles, mirrors, spoiler).

Darwantae951

Isn't that Tom R's car? I thought he said it was a K27.

-Darwin

Techno Duck

Darwin, you are correct it is Tom R's previous Turbo. He is liquidating most of his car fleet right now save his S2 and looking into something new. Ive been drooling over this car for a long time and am lucky to get the chance to eventually own it. There is a slight technicality involved in that i dont own the car yet.. but to save the logistics of it, lets just say its being 'held' for me until i come up with the rest of the money. All possible due to a good friend.

Tom did believe it had a K27, but there is nothing in the records to prove or disprove that it does. You would think for a repair bill in upwards of $1500, the place that did the work could be a bit more descriptive of the work done on the invoice! I talked to the previous-PO who had this work done and he said the car pulled much harder when the work was performed. Its hard to say what thats from, because he had a full 3-inch SFR exhaust + test pipe installed at the same time.

Darwantae951

Wow Jon, glad to hear that his car is going to a great home. Welcome to the wonderful world of boost!

-Darwin

TonyG

It looks to be a K26 compressor based on the fact that the J boot is "uncut".

The compressor inlet in a K27 is 2.75", which is substantially larger than that of the K26.

The J boot you have, appears to be stock and uncut. And if it is uncut, then it cannot fit onto a K27.

All K27's that use the J boot, have have cut it a couple inches away from the turbo in order to have the ID match that of the larger K27 inlet. This is because the radius of the J boot increases as you move away from the compressor. When this is done, a sleeve is used to couple the cut J boot to the compressor inlet.

Yours does not appear to have this done, and appears to utilize a stock J boot. Thus the compressor must be a K26 (at least the body of the compressor).

Lastly, the exhaust leak will continue increase as the exhaust gasket where the stud is missing continues to deteriorate. As this happens, you will have more and more turbo lag until the car is not much fun to drive and the exhaust leak sound drives you nuts, at which point you will be forced to fix the problem. When you fix the problem, replace all of the studs. If the stud is broken flush with the head, it's going to be very difficult to get it out with the cylinder head on the car (unless it's loose, I doubt you'll be able to do it).


TonyG

Techno Duck

Tony, thanks for the great info. Its exactly what i was wanting to know.

Ive been leaning toward dealing with the exhaust leak right now. It just means less money to throw at the go-faster stuff.. oh well .