Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

968 turbo conversion
#81

almost finished porting turbine inlet. Outlet flange adaptor will require more work to get it to fit the downpipe.



Spent a few hours with a guy down the block in his shop. He had a track version TVR and is building a Porsche tube frame 936 or something like it. Open cockpit. beautiful frame, each weld perfect. He wants it ready for Rennsport in 2 years. Will probably be powered by a twin turbo aluminum V-8 ~600+hp and will be streetable.



Also found a local guy with a worked 944 turbo. Heads up the local porsche chapter. Hope to discuss cylinder plating with him soon.
Partial Post: Please Login or Register to read the full post.
Reply
#82

Xrad, Please keep these coming, I'm completely fascinated by this.
Partial Post: Please Login or Register to read the full post.
Reply
#83

Glad some are interested!



Biggest problem I face is what to run in terms of cylinder-piston combinations.



I could stick with alusil bore and ferrocoated Mahle turbo pistons (expensive) which are made for turbo-conversion of this engine. OR, I could get the bores nikasil plated at US Chrome(extra 1000$ at least plus shipping.) If I plate the cylinders, then I have many piston choices. Tradeoff is that the nikasil coating does not last forever (look at BMW's late 90's engine fiasco). Also, US gas has sometimes high sulfur content which can really increase loss of the nikasil. and, to counter act the sulphur/nikasil interaction, you always have to use the best gas and burn at a slightly higher combustion temp. I want to avoid heat with the turbo! It could only take a few bad tanks to ruin the coating.



So, looking at cost, things may be even up front with cheaper pistons but more for nikasil v Mahle/alusil. In the long run, Mahle combo ease of use, a straight overbore to 104.5 w/ Mahle pisotns and rings (made for alusil) seems the way to go.



ANY OPINIONS??
Partial Post: Please Login or Register to read the full post.
Reply
#84

I have enjoyed this thread so far! Thanks Xrad!



As for advice- and take this with a grain of salt as I have never (and probably never will) turbocharged a vehicle of any sorts- if you are wondering which path is best between less expensive up front vs. using more expensive components specifically designed for your intended purposes- well, I think it goes without saying use the specific Mahle pistons.



Just my $0.02.



Keep up the good work- and more pictures! Please! I shall live vicariously through you!
Partial Post: Please Login or Register to read the full post.
Reply
#85

You could go with darton mid sleeves. IIRC they are about $900 for the set plus installation.





Cheap always becomes expensive!
Partial Post: Please Login or Register to read the full post.
Reply
#86

a few years ago, when i was musing about "the ultimate 968 engine" i was toying with the idea of an over-bore, new liners, and having custom made pistons - the pistons aren't all that expensive to get made in a one-off set (500-600 each) - the engine was going to cost $15k, so $2k for pistons was not that big of a deal - been there done that



if anybody could figure out how to make a turbo work properly and not need "a little more tuning", there would probably be a decent market for them, and those pistons could be made a lot cheaper in quantity
Partial Post: Please Login or Register to read the full post.

94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
Reply
#87

Hi. First to intorduce myself: I am from Finland, and building a turbocharged 3.0litre Variocam engine. I have been lurking on this site for a while, and changed few PM.s.

My approach for this build up is similar to Jägermaister Porshe, original pitons, 3,2mmm MLS headgasket. Offcourse I have searhed for other options, and so so far the best would be 104,5 mm Mahle pistons from HRM, but that would require to machine cylinders up to 104,5. I think total cost would be up to 1600-2000$. There are rumours that Wössner can make pistons to whatever specs you like, even compactible with alusil. Thi would be good option, but there are couple of questions: where to get the specs of the piston? Do they really work with Alusil? etc.

With my build up I am going to keep the boost in reasonable level, and take good care of intake and exhaust tempeatures, and so hope that my setup will survive. I am aware that big part off the engines huge potential will be lost doing this way, but first I target 350-400hp. If it stays together and I get hungry, I can allways uppdate the cylinders and pistons.
Partial Post: Please Login or Register to read the full post.
Reply
#88

good question - they might expand too much, and with the added heat of the turbo, this could cause dry run



that's why, if i do this, i will be looking into steel liners and try to avoid the whole mess



of course, with the fuel changes, and all the sulfur reductions over here, it may not be an issue anymore anyway - that whole nikasil/alusil debate is pretty outdated
Partial Post: Please Login or Register to read the full post.

94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
Reply
#89

Hey X, This is the best thread I've read on this, or any other, forum so far. Dude, you are doing EXACTLY what I've been trying to for years. You are living my dream! I don't possess the technical knowledge you all do regarding our beloved cars, but to compenstate, I was just going to hire out my lack of expertise to those who DO possess the wherewithall to accomodate my needs.



If it's worth anything, I am absolutely captivated by your posts and I hang on every word, number and calculation. AWESOME pictures!!! All I can say is thanks for letting me (and US!) live through you during this amazing journey.



Here's my "story for the day": I thought about your work so far on this project and this post as the frau and I were blowing down the A7 today in glorius chrystal clear 70 degree weather, foot on the floor 150 mph only to get friggin' smoked by an Audi RS4. <img src="/forum/images/smilies/968/mad.gif" class="smilie" alt="" /> Sheesh! Embarrasing. My wife was poking fun at me about Audi this and Audi that and blah blah blah. <img src="/forum/images/smilies/968/mad.gif" class="smilie" alt="" /> Okay, so her A6 2.7T is pretty fast... what-freaking-ever. I hope and pray you are able to make this dream become a reality for so many selfish reasons. Not the least of which is so I can cram some crow down the gullets of a few non-Porsche driving folks. <img src="/forum/images/smilies/968/tongue.gif" class="smilie" alt="" />



I'm not hatin', I'm just tired of not being able to "keep up" with the proverbial Jones's.



Rock on brother! <img src="/forum/images/smilies/968/biggrin.gif" class="smilie" alt="" />
Partial Post: Please Login or Register to read the full post.
Reply
#90

Lonestar968, a little secret xrad isn't telling you is that he has a Bimmer sedan/grocery-fetcher that might be faster on the highway than his 968!
Partial Post: Please Login or Register to read the full post.
Reply
#91

X,

The "check" is in the mail...
Partial Post: Please Login or Register to read the full post.
Reply
#92

Smokie: Yeah, 'check in the mail"..you know how that goes.....I did not believe you until you called!!! THANKS <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" /> <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />



Spoke with a forum member Mikeo, US chrome, JE pistons, and Engine Builder's Supplies of Reno about the cylinders. Seems that some recommend plating and some recommend alusil with the coated pitons. JE can make special pistons coated with "toughcoat" which will cost about 750$ w/rings!!, and can fit in standard or oversized bore...but oversized rings could be an issue with the JE's.



What I think will determine the approach will be the original bore measurements. If they are out, and I need a bore and hone, I will probably go with the ferro coated Mahle and send the block to Jason of HMR. emailed them a few times and still waiting for some resonses, though.



Time and research will reveal all....
Partial Post: Please Login or Register to read the full post.
Reply
#93

RDH: thanks for the s2 head tip. Checked it out. No cams, or any internal parts, no cover, too expensive. S2 head has the old style tensioner, some say with known faults(looks like 928 version). 968 head has the three bolt tensioner. For baseline tuning, i will disable the variocam. when things are good, i might try to use it in the higher rpm range. Probably only little gain to be had with it working under boost.



Smokie: received a flat box today containing a slightly worn fiberglass part, no supporting plywood. Luckily, no shipping damage. will need some fiberglass repair and some additional mounting metal supports installed. Since I have much experience with fiberglass composites, should be an easy fix. Overall, I am finally satisfied! <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" /> And it is VERY light, no strain on the front bumper cover!
Partial Post: Please Login or Register to read the full post.
Reply
#94

Make a mold from it and and go into business.
Partial Post: Please Login or Register to read the full post.
Reply
#95

Little more research:



Will go with three inch turbo down exhaust (except the 2.5 x 12 inch turbo outlet pipe). Probably Lindsey racing full stainless exhaust system. The turbo outlet is 2 7/16, downpipe is 2.5 inch ID. and this will feed into a 3 inch exhaust about 12 inches from turbo outlet. With cat delete pipe (and the ability to replace the cat per Lindsey racing), there will be as minimal exhaust pressure as possible



Figured out the turbo oil return. As many of you probably already know, there is a bolt already in place on the driverside oil pan which should perfectly fit the 944 turbo oil return line bung and banjo bolt. Just had to double check that my pan had one too. Looks like mine has never been removed. you can see it by looking down towards the pan from right in front of the master cylinder.



It becomes very convenient to do this conversion because of so many similarities between the 944/951 and 968.



Last big ticket items:

1) haltech E8 (with new (one year old) programming that allows about +/- 15% fuel control with wideband sensor ...makes tuning easier) ~1000$ with harness

2) Lindsey exhaust ~1100$ w cat

3) block work (pistons, bore and hone, shipping) ~3000$

4) headwork (valves, guides, etc) max 2000$

5) extra bolts, clamps wiring, injectors, intake filter, tubing, all new engine seals,bearings, h2o pump, etc 2000$ max

6) HMR radiator ?~800$

7) intake welding ~100-200?

8) carillo or HMR rods 1200$



= 12,000 max

+ parts already obtained 1700$



and trans rebuild w/LSD 2500$

and new paint and body work 5000$



OK..so I am going a little over the 10,000 budget, but it is in increments....and I am also buying well made parts and trying to do this the right way. What can I say, I really like this car.
Partial Post: Please Login or Register to read the full post.
Reply
#96

On my engines oil pan ther was just a place for bolt. It was little bit difficult to find a place wher they have suitable tools to tap the oil return line. Also aligning the oil pan straight to the bolt was also little difficult. Anyway it is no done.

For oil feed line I took it from balance shaft cover, just like on 951. I do not know should it have been done otherwise, for example from oil temperature sensor? Would be easier, and the problems with 951 number 2 crank journal bearing may relate to that turbos oil feeding.

For exhaust side I did 3" downpipe and will do 3"-3,5" after that, just to minimize backpressure. Doing downpipe was so easy, that I wonder how come anywone pay 1000$ for aftermarket part?
Partial Post: Please Login or Register to read the full post.
Reply
#97

I agree Grisen.



The balance shaft cover already has the place for oil tap cast at the raer, just need to drill and tap...easy. will jet the turbo oil feed line so I don;t lose too much oil pressure. I will post picture of bolt in pan.
Partial Post: Please Login or Register to read the full post.
Reply
#98

here is a shot of the bolt into the pan...looking down from the area of the master brake cylinder. i think this car has always wanted to be a turbo...or I just got one of the left over oil pans during manufacture. This is a 92 early production model. Anyone else have this??? Is my car special???? <img src="/forum/images/smilies/968/biggrin.gif" class="smilie" alt="" />
Partial Post: Please Login or Register to read the full post.
Reply
#99

You obviously have turbo oil pan, good luck. On mine pan there was just a casting where the bolt should be tapped. My engine is -93.
Partial Post: Please Login or Register to read the full post.
Reply

Strange!!! Must have been porsche off the shelf leftovers......



also, i did not think that the 951 turbo pan would fit the 968....



anyone else have one?
Partial Post: Please Login or Register to read the full post.
Reply


Possibly Related Threads…
Thread / Author Replies Views Last Post
Last Post by Monstrous4Banger
06-02-2011, 06:11 AM
Last Post by xrad
06-16-2009, 01:58 PM
Last Post by Ryan
02-03-2009, 04:54 PM
Last Post by 333pg333
02-08-2008, 02:35 PM
Last Post by flash
10-05-2007, 12:22 PM

Forum Jump:


Users browsing this thread: 1 Guest(s)