I could start with a shopping list and I suppose from the shopping list we should be able to get to a sort of a rough guide ; it will not be a complete 'how to' course but it will give you some idea of how I did it ...
First of all the route I took was to buy a second 968 engine and a damaged 968. the engine because I wanted to keep my original 968 engine in one piece and because it's easier to build the Turbo engine on a stand and then swap engines. Furthermore I did not want my 968 to be in bits and pieces for months and month, not being able to drive it whenver the sun did shine and the Nordschleife was open <img src="/forum/images/smilies/968/wink.png" class="smilie" alt="" /> The bonus in this modus operandi is that there is not to much pressure on the timeline because the car is running until the moment of the engine swap ...
The damaged car comes in handy because you'll need to fit and refit and modify anf refit and .... well, you get the point ... exhaust, enigine mount, line up torque tube and gearbox, Turbo, charge cooler, waterpump and radiator and so on. Since I didn't want to damage the engine bay of my 968 to much, and, again, keep my 968 running as long as possible this worked out fine for me ...
I chose te re-alusil my ( second ) engine. If you are lucky and while stripping the engine the Alusil in the cylinders is still in great shape ( I doubt if this ever is ) you may skip this step, though I wouldn't / didn't. It is not cheap, I paid some 1200 Euro but that included a titanium coat of the the piston rings. The Alusil guy told me that was the best way to go ... so I did.
Then I ordered a set of forged pistons @ Wössner, who was happy to make them in a 8,5 : 1 ratio in exchange for 1230 Euro's. Since Mr. Wössner was not able to supply me with forged con rods for some months I decided to spent another 700 Euro's on forged conrods via Ebay Australia.
Why I chose the 8,5 : 1 ratio rather then a higher compression is because I'am looking for a smooth ride with a sharp edge rather then max power at a higher rev count. For me the combination of a lower ratio with a smaller turbo ensures me I'll have pressure from ( almost ) idle on so I do not need much torque from the engine itself ( the N/A stage ). The guys building the larger turbo's need to get to 4000 rpm before the monster comes out and that's just not my cup of tea ( though they will, in the end, have a stonger engine, mine will be faster ). That's a choice everybody needs to make for themselves ...
Wow, this is going to be a long story ; taking a break,
to be continued ...
Cheers, Frank
Thanks for the info. Yes, I completely agree that building the new engine on a stand while the one currently in the target car stays running is a great way to go. It's amazing how much custom work is needed, especially with regard to the engine mount, exhaust, torque tube, etc.
I also find your selection of compression ratio and turbo size intriguing, and compelling. I would have thought dropping the compression so much would result in a lot of lag due to the impact on the power until the turbo kicked in, but it sounds like you sized the turbo such that it kicks in fast enough to not make this a problem. Very clever...
Your passion, and the amount of fun you had creating this engine, really comes through.
One week and some 500 km down the road the engine is running just fine ; not a single drop of fluid or exhaust leaks or any of that stuff and it sounds like it's having fun setting the horses free on the road.
Which doesn't mean we did not run into any trouble ..... Here is a don't don't don't ...
Don't ever buy a SPEC Alu flywheel for your 968 unless you have a track car and don't mind getting shaken and stirred during ( every single ) take off and don't mind annoying noises @ 2200 rpm and 2800 rpm in first 3 gears. The upside of the flywheel is that it revs up much better than the dual-mass flywheel, but it's just not suited for the road.
When I ordered my Stage 3+ clutch & flywheel I was more or less mislead by the pictures on the SPEC website, showing me a clutch with springs. On the car-specific page there were no additive pictures for the clutch for our 968's so I thought I would receive a spring clutch .... I should have know better ... Our 968's do not have springs in the standard clutch, the Dual Mass flywheel takes up any vibrations from releasing clutch, accelarating and decellerating and so on. It would have been nice if the guys @ SPEC would have stated on their 968 page that buying an Alu flywheel is not suitable for road-use. Now they just answer my e-mail saying 'there is no room for springs in a 968 clutch assembly' ( which I doubt ) ...
Anyway the result was that I was not able to find any way to take off in a decent manner ; always shaking, sometimes stalling and always the annoying noises in the first 3 gears. At first I thought something was wrong in the ( lining up off the ) gearbox ( the noise is as loud at the gearbox as it is at the Clutch-housing ) so I changed the gearbox with my spare but .... same story ... so it wasn't in the gearbox.
Then I hoped a vibration damper, as mounted on a 944S2 may resolve most of the vibration noises but again ; no points ....
This story end with me changing the Alu flywheel back for the standard dual mass flywheel with which I got rid of the noises and the vibrations ... a waste of a $ 700 Alu flywheel .....
But do have a merry Christmas, guys ! <img src="/forum/images/smilies/968/wink.png" class="smilie" alt="" />
Cheers, Frank
By the way : I found out that the 944 Turbo does have a spring-clutch and, as I'm told, is the same in diameter as the 968 clutch. Anyone can confirm or deny ? and is the thickness of the combination ( flywheel, pressure plate and clutchplate ) the same as 968 ? in other words, could I put in a 944 clutch with an Alu flywheel ? ? and will the <acronym title='top dead center'>TDC</acronym> sensor still work ?
I would go with an aluminum flywheel if I could pair it with a sprung clutch disc. I have this setup on my BMW and it's just as smooth and quiet as stock. Some gear rattle at idle when the trans fluid is hot, but that's it.
[quote name='Dimma' timestamp='1324661291' post='119507']
One week and some 500 km down the road the engine is running just fine ; not a single drop of fluid or exhaust leaks or any of that stuff and it sounds like it's having fun setting the horses free on the road.
Which doesn't mean we did not run into any trouble ..... Here is a don't don't don't ...
Don't ever buy a SPEC Alu flywheel for your 968 unless you have a track car and don't mind getting shaken and stirred during ( every single ) take off and don't mind annoying noises @ 2200 rpm and 2800 rpm in first 3 gears. The upside of the flywheel is that it revs up much better than the dual-mass flywheel, but it's just not suited for the road.
When I ordered my Stage 3+ clutch & flywheel I was more or less mislead by the pictures on the SPEC website, showing me a clutch with springs. On the car-specific page there were no additive pictures for the clutch for our 968's so I thought I would receive a spring clutch .... I should have know better ... Our 968's do not have springs in the standard clutch, the Dual Mass flywheel takes up any vibrations from releasing clutch, accelarating and decellerating and so on. It would have been nice if the guys @ SPEC would have stated on their 968 page that buying an Alu flywheel is not suitable for road-use. Now they just answer my e-mail saying 'there is no room for springs in a 968 clutch assembly' ( which I doubt ) ...
Anyway the result was that I was not able to find any way to take off in a decent manner ; always shaking, sometimes stalling and always the annoying noises in the first 3 gears. At first I thought something was wrong in the ( lining up off the ) gearbox ( the noise is as loud at the gearbox as it is at the Clutch-housing ) so I changed the gearbox with my spare but .... same story ... so it wasn't in the gearbox.
Then I hoped a vibration damper, as mounted on a 944S2 may resolve most of the vibration noises but again ; no points ....
This story end with me changing the Alu flywheel back for the standard dual mass flywheel with which I got rid of the noises and the vibrations ... a waste of a $ 700 Alu flywheel .....
But do have a merry Christmas, guys ! <img src="/forum/images/smilies/968/wink.png" class="smilie" alt="" />
Cheers, Frank
By the way : I found out that the 944 Turbo does have a spring-clutch and, as I'm told, is the same in diameter as the 968 clutch. Anyone can confirm or deny ? and is the thickness of the combination ( flywheel, pressure plate and clutchplate ) the same as 968 ? in other words, could I put in a 944 clutch with an Alu flywheel ? ? and will the <acronym title='top dead center'>TDC</acronym> sensor still work ?
[/quote]
Yep. Im looking at one on a motor in my garage now.
That's good news ! <img src="/forum/images/smilies/968/smile.png" class="smilie" alt="" /> Is yours a 968 Alu flywheel with a 944 Turbo ( spring ) clutchdisc and a 968 pressure plate ? or any other combi ?
[quote name='Dimma' timestamp='1324675328' post='119522']
That's good news ! <img src="/forum/images/smilies/968/smile.png" class="smilie" alt="" /> Is yours a 968 Alu flywheel with a 944 Turbo ( spring ) clutchdisc and a 968 pressure plate ? or any other combi ?
[/quote]
No. All 951. Its a spare 2.5 motor. The disc was on the car when I bought it. believe its a sachs. It is the same dimensions though. You should have no problem using whatever combination you want, as far as fitment is concerned. My 3.0 8v on my 951 is using a 930 disc, and 951 flywheel, pressure plate, etc. with harmonic dampener on the crank. 15k miles so far.....runs like a raped ape. I need to rebuild the tq tube now though, its shot. Im in the 400's to the wheels, and can say from experience, expect to rebuild yours with 525. Dont be too hard on the 01e either. Unless you dont mind snapping things. The transaxle should hold up, but always rev match, and I wouldnt launch it personally. when you rebuild your tq tube which will probably be not too far down the road with your power, especially the 968 tq tube it has a slot in the front they put in there to counteract vibration. You want to swap out to a earlier tq tube all together really, the 968 tubes are apparently harder to rebuild for extra power. Dont bother with a new OEM tube, and stock bearings. Give Constantine a shout.
http://www.blacksear...oducts&Itemid=9
The 968 is built from the same basic parts bin, as the 944's, and late 924's. Almost everything is interchangeable. Something to keep in mind when modding these things. After all it was almost named the 944s3....Im guessing the marketing dept had other ideas.
Yeah, you have to be careful here. I talked to Pete Fitzpatrick of RS Barn, and he told me it gets pretty tricky. For example, a number of pressure plates actually fit the 968, but if you don't get the one with the correct (and I'm afraid I don't know the correct technical term) pivot point/total travel, it won't feel right - it will require a lot more force to disengage, without actually offering any additional clamping force against the flywheel. I hope I didn't misquote him... And he was emphatic that a spring-centered disk won't work. I just guessing here, but it sounds like the problem may be with the bolt pattern on the 968's crankshaft. This would explain why certain disks works on a 2.5, but not on a 3.0. Again, just a guess...
[quote name='Dimma' timestamp='1324679569' post='119527']
That's strange, reading this :
]http://www.968forums.com/topic/11304-are-light-flywheels-really-a-good-idea-on-these-cars/page__view__findpost__p__119513]
[/quote]
Hmm, I guess
"should" being the key word there. <img src="/forum/images/smilies/968/laugh.png" class="smilie" alt="" /> I havent tried many different combinations, or ever bought an RSbarn flywheel. You'll def want to cross your t's, and dot your i's. Too many combinations to factor in when you consider the variety of aftermarket possibilities. Many combinations do work, not surprising some dont. Ive never actually run or experimented with the exact set up your looking to implement. Its what makes them "custom", and also modification a slippery slope.
[quote name='Cloud9...68' timestamp='1324681801' post='119533']
Yeah, you have to be careful here. I talked to Pete Fitzpatrick of RS Barn, and he told me it gets pretty tricky. For example, a number of pressure plates actually fit the 968, but if you don't get the one with the correct (and I'm afraid I don't know the correct technical term) pivot point/total travel, it won't feel right - it will require a lot more force to disengage, without actually offering any additional clamping force against the flywheel. I hope I didn't misquote him... And he was emphatic that a spring-centered disk won't work. I just guessing here, but it sounds like the problem may be with the bolt pattern on the 968's crankshaft. This would explain why certain disks works on a 2.5, but not on a 3.0. Again, just a guess...
[/quote]
Its been a while since I had a 968 crank out to look, at....but pretty darn sure its the same bolt pattern. Im using a spring centered disk on my 3.0, with a 968 crank. Only difference of the cranks is a longer stroke. Did he mean it doesnt work with his flywheel? I may be slightly confused here what combo were talking about exactly.
Flash could answer this a lot better than I could, but my understanding is that a spring centered disk won't work with a SMF. What kind of flywheel do you have on your car? Bottom line is that Flash and Pete spent many months trying to create a spring centered disk to work with a SMF to reduce the gearbox rattle, but in the end it proved to be impossible.
951 flywheel is what Im running currently.
Wow, great work. I want Santa to bring me a conversion package for Christmas.
I do consider myself lucky because of the fact that I know where Frank lives ;-) Maybe he'll take me out for a ride some day.... One can dream, right?
this has gotten a bit far afield from the turbo build topic, but to correct something, the 968 uses a DMF that is specific to that car. it was used on no other. this is wherein the problem lies. both it, and all of the aftermarket flywheels, do not have enough room for the springs of any OEM disk that fits with the pressure plate and driveshaft (i bought them all and tried them), nor do they have enough room to safely be machined down to allow for them.
machining the hardware is a VERY bad idea, and does not allow for enough room anyway to have any real lifespan from the disk (as it wears it gets closer to the hardware)
i had disks made that cleared the hardware ok, but could not find springs that worked (and i tried quite a few, including a poly compound). we constantly had a chatter problem, no matter what friction material we used.
if anybody figures it out, i'll probably buy one. i gave up after way too many clutch jobs and entirely too many failed disks. i am back to stock friction disk and an 18lb flywheel, with no problems at all, other than the 2300 rpm rattle. i only went to the 18 though because of the supercharger. otherwise, the 12 was fine.
I will be interested to see how the PWR cooler works with 1 bar of boost. Having tested them before they do heat soak rather quickly once you start pushing them
Well done on what appears a fabulous build. It looks spectacular!
Keep the updates flowing, thanks for sharing.
As an aside, is that bonnet carbon, or is it just the light in the pictures?
@ Flash : Thanks for all that info ; I'm still trying on getting the clutch to work without wobbling and noises but no luck so far. We have remounted the <acronym title='dual mass flywheel'>DMF</acronym> but still wobbling with the Spec stage 3+ plate. We'll now put back the stock plate and see how that works out. The <acronym title='dual mass flywheel'>DMF</acronym> did kill the noise so that defenitely is in the ALU flywheel ( mine is a Spec 12Lbs one ). Did you ever investigate the 944/951 possibilities and/or what does the 928 use ?
@ MC968CS : must be the light in the pictures ...
Happy Newyear, guys !