Show full size 924Board.org
Discussion Forum of 924.org
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
 Technical FAQ924 FAQ (Technical)   Technical924 Technical Section   Jump to 924.org924.org   Jump to PCA 924 Registry924 Registry

K26/6 to K27/6 Turbo Mod WITH pics
Goto page 1, 2, 3, 4  Next
 
Post new topic   Reply to topic    924Board.org Forum Index -> Performance Upgrades
View previous topic :: View next topic  
Author Message
sequential  



Joined: 18 Nov 2005
Posts: 500
Location: BANNED

PostPosted: Mon Mar 06, 2006 1:37 am    Post subject: K26/6 to K27/6 Turbo Mod WITH pics Reply with quote

Well i have pulled the trigger on this one and went ahead and had a S1 K26
modded to a K27/6 setup. This will allow me to run the stock manifold for now until certain unnamed associates can keep their promises and finish my exhaust manifold . The mod will have a K27 front housing , backing plate and wheel attached to a stock S1 K26 Turbo, of course we will see what the dyno numbers produce . Also the chassis leg has to be modified for the k 27 front to fit i will have pics of how much and if it is worth it etc. i should have the turbo in hand within a week .
_________________
928 gts prototype
baby blue engine block
steam in 1,2,3,4 sometimes
cold star issues while on stands
112 whp with new 4 valve head and MIS 2


Last edited by sequential on Wed Apr 12, 2006 9:39 am; edited 1 time in total
Back to top
View user's profile Send private message
ESC944  



Joined: 21 May 2004
Posts: 747
Location: FL

PostPosted: Mon Mar 06, 2006 3:48 am    Post subject: Reply with quote

Sounds good - to me -

I know this was hashed around before - curious about the Garret KKK Clones... When I get around to more serious modifications to the 931.

Will be watching your results closely.
Back to top
View user's profile Send private message
Raceboy  



Joined: 01 Mar 2004
Posts: 2321
Location: Estonia, Europe

PostPosted: Mon Mar 06, 2006 3:58 am    Post subject: Reply with quote

I put K28/6 to the stock location and the mounting had to be modified. It's just about the maximum size to use, otherwise stock manifold and mounting won't work.


_________________
'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S
'91 944 S2, sold
'82 924S/931 "Gulf", sold
'84 924, turbocharged, sold.
http://www.facebook.com/vemsporsche
Back to top
View user's profile Send private message Visit poster's website MSN Messenger
Kenodog  



Joined: 25 Jun 2003
Posts: 2584
Location: Vancouver,B.C.

PostPosted: Mon Mar 06, 2006 4:39 am    Post subject: Reply with quote

Holy crap Raceboy that things huge ! Like those flat tops too.
_________________
1979 Euro 931, Olive
1981 931, Sabine
2014 Mazda CX-5 (Kinderwagon)
2008 GS500
2016 DR650
2019 KTM 790 Adventure
Back to top
View user's profile Send private message Send e-mail MSN Messenger
sequential  



Joined: 18 Nov 2005
Posts: 500
Location: BANNED

PostPosted: Mon Mar 06, 2006 5:14 am    Post subject: Reply with quote

Raceboy ,
The problem is not to the block, but to the frame rail , you will have to modifiy the frame rail deeply for that size turbo to fit.
_________________
928 gts prototype
baby blue engine block
steam in 1,2,3,4 sometimes
cold star issues while on stands
112 whp with new 4 valve head and MIS 2
Back to top
View user's profile Send private message
Raceboy  



Joined: 01 Mar 2004
Posts: 2321
Location: Estonia, Europe

PostPosted: Mon Mar 06, 2006 5:21 am    Post subject: Reply with quote

sequential wrote:
Raceboy ,
The problem is not to the block, but to the frame rail , you will have to modifiy the frame rail deeply for that size turbo to fit.


Yes, I already did it too. At first I was little hesitated about cutting the frame rail, but it actually needs modifying more to the front of the crossmember mounting point, so the rigidity of the frame won't be compromized.

Kenodog, don't let it scare you It is really big, but it's efficiency is only tad higher than K27-7200 found on the 964 Turbos (965). Though it flows pretty good, I read on the Rennlis and saw some pics that RUF used that K28 housing together with K29 comp wheel (like mine) for upgrading 965's.
What concerns the intercooler, I'm now between two options, both of them are readily doable and available. One is to use Nissens core and make 100mm thick GTR style IC, second option is to make IC out of two 951 units (welded as one, side-by-side) and vertically, like GTR style too. Hence the turbo outlet facing downwards. From there right to the IC, up through it and straight to the log-style intake. That would be shortest way to do it.
But, with 951 IC's I'd have to cut them a bit shorter. That would be a waste though.

EDIT: Wayne, sry for hijacking your thread
_________________
'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S
'91 944 S2, sold
'82 924S/931 "Gulf", sold
'84 924, turbocharged, sold.
http://www.facebook.com/vemsporsche
Back to top
View user's profile Send private message Visit poster's website MSN Messenger
sequential  



Joined: 18 Nov 2005
Posts: 500
Location: BANNED

PostPosted: Mon Mar 06, 2006 5:45 am    Post subject: Reply with quote

the turbo wont work facing downwards raceboy it will be in contact with the
steering rack . I have decided to roll the frame rail to make just enough clearance for the turbo, instead of cutting it .

What about compressor surge with the k28 and small k26 back housing . just from a visual standpoint , the k28 looks to be the same size as the k27 that was shown to me .
_________________
928 gts prototype
baby blue engine block
steam in 1,2,3,4 sometimes
cold star issues while on stands
112 whp with new 4 valve head and MIS 2
Back to top
View user's profile Send private message
Raceboy  



Joined: 01 Mar 2004
Posts: 2321
Location: Estonia, Europe

PostPosted: Mon Mar 06, 2006 6:25 am    Post subject: Reply with quote

I "made" it to work facing downwards. No other way for me
Making some calculations for that K28 and 931 engine lead me to the conclusions that it should be right on the edge bfore surge line on the map. But, time will tell for sure.
I don't expect anything drastic because the trim of the comp wheel is pretty small and I'm going to use 3" exaust + venting the wastegate to the atmosphere so that backpressure won't be a problem too. Surge is basically engines inability to consume air produced by a turbocharger in a given pressure rate.
Of course with stock head that still could become a problem but I'm going to do some good mods next autumn ( bigger ss valves with 7mm stem, plus some port "straightening", 3 angle valve job etc).
Our fellow board-member Jesper (username Racing) had K27/6 on his 931 and it ran without an itch with 2 Bars, go figure.

EDIT: I've done some extensive comparing between 931 hotside housing and 951 /8 hotside. 931 hotside exit is basically the same diam and opening slot for the turbine is also the same width. Only difference is the turbine inlet (smaller and 3-bolt).
_________________
'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S
'91 944 S2, sold
'82 924S/931 "Gulf", sold
'84 924, turbocharged, sold.
http://www.facebook.com/vemsporsche
Back to top
View user's profile Send private message Visit poster's website MSN Messenger
sequential  



Joined: 18 Nov 2005
Posts: 500
Location: BANNED

PostPosted: Mon Mar 06, 2006 7:25 am    Post subject: Reply with quote

Raceboy , how are you getting the turbo not to interfere with the steering rack .pointing down
_________________
928 gts prototype
baby blue engine block
steam in 1,2,3,4 sometimes
cold star issues while on stands
112 whp with new 4 valve head and MIS 2
Back to top
View user's profile Send private message
Tigger937  



Joined: 11 Apr 2004
Posts: 906

PostPosted: Mon Mar 06, 2006 7:38 am    Post subject: Reply with quote

Forgive my ignorance, but what is the advantage of the flat tops? I thought the concave tops were there to improve swirl/evacuation in the combustion chamber. Or is this not so critical in turbo applications? Wouldn't that also increase CR which is bad for boosted applications?

BTW, very nice work! As my signature so aptly states, I love to see this kind of stuff being done.
_________________
1981 931 (Concours)
1982 931 (Daily Driver)

"Think outside the box"


Last edited by Tigger937 on Mon Mar 06, 2006 8:35 am; edited 1 time in total
Back to top
View user's profile Send private message
Lizard  



Joined: 03 Nov 2002
Posts: 9364
Location: Abbotsford BC. Canada

PostPosted: Mon Mar 06, 2006 8:24 am    Post subject: Reply with quote

more compression on a boosted engine isnt really a bad thing it is all about what you plan on doing, I will be boosting a 10:1 CR 5.0L 928 engine with 10-12PSI of boost and an intercooler, as long as your intake charge is not too hot, you have enough ign retard under boost, your cyl temps/exhaust gas temps are within spec, and you dont have any sharp edges in the chamber that will cause a hotspot and lead to detonation

though with the 928 the port design is far superior to the 924/931, which really does help
_________________
3 928s,
Back to top
View user's profile Send private message Send e-mail
Raceboy  



Joined: 01 Mar 2004
Posts: 2321
Location: Estonia, Europe

PostPosted: Mon Mar 06, 2006 4:42 pm    Post subject: Reply with quote

Wayne, when engine is mounted in place, the turbo is not facing vertically downwards, more parralel to the engine block angle. Plus the turbo sits a bit higher than crank pulley. In worst case I have to shorten the turbo outlet and weld 90-degree piece there which gets the pipe diam to 3" and that's going to the IC. Outside IC goes smaller, 2,75" pipe. Why? Because as air gets cooler it also gets denser and cooling causes pressure drop. To compensate that a little, "specialists" suggest smaller IC outlet.

EDIT: Tigger, these flat-tops won't up the compression because they sit 5.8mm below the deck. That combined with 2mm head gasket and a bit modified combustion chambers leads us to app. 7.8-7.9:1 ratio.
On boosted situation (at least with crappy comb. chamber design like 931's ), flat-tops are good not having sharp edges that can produce detonation when getting hot.
And, last but not least, with those pistons and head gasket, my engine is non-interference
BTW; GTR had flat-tops too, that means they are the right choice for that engine. 375hp is something to consider
_________________
'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S
'91 944 S2, sold
'82 924S/931 "Gulf", sold
'84 924, turbocharged, sold.
http://www.facebook.com/vemsporsche
Back to top
View user's profile Send private message Visit poster's website MSN Messenger
bass gt  



Joined: 02 Dec 2004
Posts: 971
Location: Johannesburg for now!!

PostPosted: Mon Mar 06, 2006 6:41 pm    Post subject: Reply with quote

Raceboy,

Where did you get the pistons from? Any specs you can pass on, as I'm looking to rebuild a motor myself.
Thanks,

Steve
Back to top
View user's profile Send private message
Raceboy  



Joined: 01 Mar 2004
Posts: 2321
Location: Estonia, Europe

PostPosted: Mon Mar 06, 2006 7:24 pm    Post subject: Reply with quote

Sure, no problem. I got them from www.dalhems.se , they cost about 450$ /set including shipping from Sweden to Estonia. Pistons are forged Mahles, originally made for VW bug performance engines. Available in 87-94mm, compression height is available in their site, as do prices.
Pistons are graphite coated and they come with 22mm wrist pins (you'll need to rebush the rods) and rings.
_________________
'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S
'91 944 S2, sold
'82 924S/931 "Gulf", sold
'84 924, turbocharged, sold.
http://www.facebook.com/vemsporsche
Back to top
View user's profile Send private message Visit poster's website MSN Messenger
morghen  



Joined: 21 Jan 2005
Posts: 8177
Location: Romania

PostPosted: Mon Mar 06, 2006 9:49 pm    Post subject: Reply with quote

wow !!

thats awesome ! a 924 Turbo NON interFEAReance !!! great man !

i cant wait to see it runing !
_________________
Ruby-sh 924
Back to top
View user's profile Send private message Visit poster's website Yahoo Messenger MSN Messenger
Display posts from previous:   
Post new topic   Reply to topic    924Board.org Forum Index -> Performance Upgrades All times are GMT + 10 Hours
Goto page 1, 2, 3, 4  Next
Page 1 of 4

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group