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968 turbo conversion

What I have heard, porsche has used these (951) oil pans also in nonturbo models, propably quite random. I also heard, that you can find allready tapped balance shaft cover in nonturbos. Late turbo oil pan fits 3.0litre engines. On my previous engine (951 s) the oil pan was cut in two peaces, by broken conn. rod, so I could not use it <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" /> . I shall post some pics off my previous and coming engine
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IIRC, The balance shaft covers are unique to each block (ie they are aligned bored before assembly at the factory and are matched to the specific block)



Would love to know more about your build up.
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As I previously mentioned, my engine is built up allmost alike as Jägermaister Porsches engine, wich I assume you all have read from Rennlist.

It is based on 93 968 engine, original pistons, Carillo conn rods, thick MLS headgasket (3,2mm). Exhaust plumbing:. from 968 headers with new flanges to fit 951 cross over. Garrett Gt35/82R turbo, 3" downpipe. Original 951 wastegate modified to dual port style. VEMS engine management, ractronix big injectors (about 900cc/min), bosch 044 fuel pump etc. Lots of parts come from my previous 951 turbo engine. Intake manifold is yet to be built, but some kind off plenum system it will be. Engine is hopefully ready for next spring.
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I have all the photos from Marcus' build up.

If you need the manifold fab pics send me a Pm with your email address and I will send them to you.
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X,

Sent a bunch of pics.
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Did not get them. Comcast tends to cut out my emails with high res pics. might have to put them into a compressed folder and send again.

THANKS!!
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I will post them here, much easier.



more
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I have also those pictures saved. I thought changing turbo outlet and plenum inlet, would be easier to rout all those tubes, something like Lindsey racings turbo intake manifold.
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Yes, I have seen these. I decided that since I will be running 8.5:1 comp, longer runners would be better for me on the street at low rpm's. The 944 turbo plenum / runner connection has radiused inlet already built in for each runner. runner volume calculated at about .339 L (1.3L total) and plenum volume stays the same at .76L. The plenum volume is a little low for the 3.0. overall volume of the intake is 2.06L which should be fine for low end. With single throttle plate, in combination with longer runners, I should have good low end power. mid-Top end would obviously suffer, but that is where the turbo comes into play. Also, design requirements require small intake package because of my larger turbo compressor. And also the visual appeal of the polished Porsche runners and plenum add to the package.



For these reasons, i have chosen the 968/944 hybrid intake design. it will require some inner weld tube matching and grinding to get things smooth, maybe extrude hone if the welds seem strong enough.........



if this setup does not work, at least it is easy to change to another design.
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Puuuuurrrrdy!
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received a set of new 951 turbo bolts and seals. Bolts fit the garrett turbo perfectly. Also, picked up a 951 throttle body. this may be slightly narrow for normally aspirated but is still wide enough for turbo 3.0 application...just barely. May upgrade later to something bigger if needed. Makes installation much easier.



951 TPS has a 6 prong Bosch connector which can be found at eagle day (AMP junior connector). Still have not heard back from Jason Lee at HMR.
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Throttle body comparison:



If I was to build my own intake manifold, I would consider using a slightly larger throttle body. For ease of build and cost savings, I have chosen 951 intake mated to 951 throttle body. My other throttle body only offers a 60mm plate and the porsche has a 59mm plate. The slight diameter loss is worth the ease of installation (problem being the gasket- backside photo)



Both TB's set up the same way with a driver side cable, the mitsu has a more aggresive throttle lever arm arc. Big thing was that looks like someone messed with the 951 TB because the shaft coil spring was actually opening the plate while the long spring was needed to close it. In otherwords, the springs would fight each other when opening more than half throttle. NOT GOOD. if the cable breaks, I do not want a floating throttle plate.



Took me a little bit to get it apart and reconfigure the coil spring so that it actually closes the plate by itself, and when the long spring is hooked up, the plate closes with authority, but not too tight so as to wear the cable or bearings. It is only a little more tight than the Mitsu springs, which are dual coils. Long spring is easily adjustable. And now I feel more safe knowing that if one spring breaks, the other can close the plate. I would suggest to all 951 owners to check their spring configuration. Even if competing spring setup is factory design, it is not correct IMHO. Just waiting on a new O-ring and air bleed screw.



Also, look closely at the 951 front view photo and you can see the Amp Junior 6 pin connector (50$) from Eagle Day (these guys have the fastest shipping of anyone I have ever dealt with, I have been buying parts from the for several years!) These are EXCELLENT quality Bosch style connectors but are quick disconnect style and much more heavy duty. I use them for all engine bay bosch connectors for sealing ability, durability, and ease of use. They come with the inner clips and seals, but no boot. The little seals are so good the boots are only redundant.
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On the 6 pin connector:



# 2 + 3 is the resistance circuit for the haltech to sense throttle poition. I think it is # 5 + 6 which is the on/off TPS switch, not really needed once Hlatech learns the plate position.
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I think 951 tb is a little bit small for 3,0 litre 16 valve turbo engine. Ford mustang Tb.s are available in different size for reasonable price and are relatively easy to fit to these engines. Alltough I am first going to use 951 tb, wich I allready have. This is because it is safe to restrict intake size to keep engines power in control while setting it up. Whole system will be buildt keeping in mind that later it will use bigger, propably 3" tb, 3" intake plumbing, intake manifold designed so that changing to bigger tb i easy.

About connector pins: you are right, there are one pin for wide open tb and one for closed tb, you do not need these with stand alone system. Wich pin is wich, I do not remember, but I can check tomorrow if needed.
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I will look into the ford TB's later if I mod the intake. Thanks for the tip. I would suggest that you use at least 4 inch diameter intake pipe to the compressor inlet if you use 3in piping. Neck down to 3 inch right before the compressor inlet, assuming it is a 3in compressor inlet. Especially if you are drawing in air from outside the engine bay and it is a long run...



In my build, 3 inch plumbing for 1 bar boost is too big. Even toyota supras run 2.5-2.75in pipes. And the need more room to run through the bay. 3inchers would probably only benefit you for the short time when the mani sees neg presures. since I am only looking for another 100hp, not necessary. The outlet size on the compressor is only 2 inch and the intercooler inlet outlet is 2.5in. 3.0 in pipes will add too much volume and will effect overall system flow. Also, they will add more surface area heated by the engine bay(usually, i wrap my intercooler piping from intercooler to intake with a thermal guard). No matter what, 3 in or 2.5 in pipes, your turbo compressor oulet , engine efficiency, and your TB are the size moderators with the rate limiter being the smallest opening.



The compressor we designed could flow up to ~60lbs minute which will overcome the small restriction produced by 951TB and easily be enough air+fuel for the 16v 3.0 engine.



I don;t want to go much more boost than 1 bar beacuse I have not been able to find sodium filled valves to fit the 16v head and I will not be O ringing the head.
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update to last post:



Flow through tubes should be less than 400ft sec but not sluggish. In regards to pre/post intercooler tube size: Some say smaller POST intercooler tube keeps velocity up due to the now more dense air. Others say that a LARGER post intercooler tube acts like a reserve (in conjunction with the intercooler).



I chose to keep everything at 2.5 inch which can easily flow enough air for 400hp. I was making about 300+ at the wheels with 2.5 tubes, a 2.0L, small IC, and the TB on the left above(which was at least 110hp over stock) and had plenty of reserve in the turbo which is smaller than the new one.
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Any competent machinist could hone out a milimeter or three from your throttle body. Have you considered ways to make the MAF assembly less restrictive? I mean, 5v is 5v, so why couldn't a low-restriction Granatelli MAF (for Corvettes and such) be made to fit?
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Have you tought about valve springs? I have tried to search specs about original springs without succes. They seem to be quite stiff douplle springs, and I am going to use them. I am also using original valves, off course decent valve job has been done. Also original head bolts are going to be used.
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Ahhh: finally back on line. Thanks Bob and Smokie!



Valve springs: stock will be fine at my rpm and boost level. Will replace the valves, guides and springs with new when I do the build.



MAF: don;t need it, Haltech works off MAP/TPS



Throttle body: yes, it would be nice to have a slightly larger unit, but for the ease of the build (remember, this is trying to be a build anyone can do with parts easily obtainable) and the fact that with boost at .6 bar for this size engine, the plate size is fine.



Head bolt: NO, going with HMR studs..the block will break before those studs..something like 150 ft/lbs torque on head nuts will keep leaks to a minimum.



Valve job: if you are in the detroit area, I know a great guy who does awsome headwork. Will even fit American turbo valves, guides , seats, and stronger springs all cut to appropriate length/size for probably less than stock. His US made valves have long, uncut stems and can be fitted to any length.



Anyway, I will try to keep some posting here, but in the last three weeks, I had to move the build over to rennlist '951 turbo' section. still under same name 'xrad' with pics and all. many turbo guys over there who are very helpful as well.
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very glad we sorted that out - not sure what was going on there, but happy it's resolved



i'll see what i can do about setting up a blog here for you so that you can archive everything here where it will be easy to find
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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."
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