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-   -   2004 Karrera Sedan (https://www.germanlook.net/forums/showthread.php?t=10395)

wrenchnride247 January 24th 2010 22:59

Cool deal. I have a 915, but have not tried it out yet (still have lots to do) I have heard the Berg 5 welds an extension onto the main shaft for the 5th gear. I don't like the sound of that personaly.

verbeekb January 24th 2010 23:00

911 torsion covers, 968 spring plates on 968 CS torsion bar
http://www.karrera.net/Karrera%20Sed...edan%20(7).jpg

wrenchnride247 January 24th 2010 23:00

Quote:

Originally Posted by verbeekb (Post 73692)
993 RS amplifier and master cylinder
http://www.karrera.net/Karrera%20Sed...edan%20(5).jpg

Much better size!;)

verbeekb January 24th 2010 23:04

Hmm.. I'm with you on that, but what it really has going for it, is that it FITS .. I (will) have a body in original paint that I don't want to ding up .. I'd modify the pan in a heartbeat, got a new G50 shifter set up .. but somewhat reluctant to graft it into the new pan .. that Bus box doesn't sound so bad .. I'm kinda like trying to find down sides to it.. to justify a 915.. the G50 .. I don't know ..

wrenchnride247 January 24th 2010 23:12

The berg 5 and berg bus conversions sometimes have clearence issues with the body (area where the rear seat belts mount to the body in the center) not much, but you would have to "hammer" some. ;)

verbeekb January 24th 2010 23:16

For the rest, being a parts guy and all, I keep track of any/all mods and am creating a parts book that includes all deviations from the stock 2004 Bug, similar to what Porsche Motorsport does. That makes this one repeatable .. I think/hope .. :)

I have a lead on (used, sigh..) 46 IDAs (forty six, mother of all IDAs) off of a 904. I'll have to get creative again .. on the Duc heads that would sacrifice power, but would gain torque/drivabillity. Interesting detail, there are programs for the Ducati injection system that allow tweaking of the engine management system.. since I am using the heads .. it would be relatively easy to go the Ducati way on this .. with a wasted spark and a similar injector arrangement .. But lately I got a thing for carbs again .. why not? By the time I'll drive this thing out of my living room it'll be old fashioned again .. my neighbours driving a Mk 7 electric Prius ..

verbeekb January 24th 2010 23:24

Quote:

Originally Posted by wrenchnride247 (Post 73697)
The berg 5 and berg bus conversions sometimes have clearence issues with the body (area where the rear seat belts mount to the body in the center) not much, but you would have to "hammer" some. ;)

Hmm .. I can do that without hurting it too much .. I'll make it up to her :)

wrenchnride247 January 24th 2010 23:26

With all the "new" going into this project I would go EFI. The "Ducati way" sounds very good.

Nice chatting with you... I gotta get some sleep (although its early morning for you)

verbeekb January 24th 2010 23:41

Take care, nice talking to you!

I'm all hot n bothered about a *censored* car now .. :)

verbeekb January 25th 2010 00:24

Wheels.

7.5x18" ET50 993 Turbo hollow spoke all round (I know, not hip, but they are NEW and genuine hollow spoke, why wouldn't I use them?)
http://www.karrera.net/Karrera%20Sed...edan%20(8).jpg

Pirelli P-Zero Corsa in 225/40-18
http://www.karrera.net/Karrera%20Sed...edan%20(9).jpg

Clatter February 10th 2010 02:36

let's see those heads!

how you plan on making them work??

verbeekb February 10th 2010 09:55

Pictures of a bare head:

http://karrera.net/Karrera%20Sedan/996%20(0).jpghttp://karrera.net/Karrera%20Sedan/996%20(1).jpg
http://karrera.net/Karrera%20Sedan/996%20(2).jpghttp://karrera.net/Karrera%20Sedan/996%20(3).jpg
http://karrera.net/Karrera%20Sedan/996%20(4).jpghttp://belmontcycle.com/yahoo_site_a....113145423.jpg

Not my pictures, but they will help to illustrate.

It begins with the holes that go over the headstuds, the spacing is -almost- identical to stock Type 4, however, they are like tubes incoporated in the casting, and there is very little room to move them. If they break through to a coolant pocket there would be leakage issues. The tensioners are mounted on the head itself, so there is no need to fabricate custom brackets/plates for them, can use the stock parts, along with all the Ducati internals, covers, flanges etc.

For our engines we need to marry two heads per side. There are large roller bearings in the large holes to support the camshafts, here I will need to select the correct camshafts for each side, determine timing offset, and make a keyed or splined collar where the camshafts join. There is plenty of room here, and no one says I need to use stock Ducati bearings.

The heads will need to be decked a few mm between them so the combustion chambers will be centered over the cilinders, there is very little room to do this, I may have to leave them a little off center.

These heads are designed to work with the 66mm stroke that I am using, the Duc has the same stroke. Torque is a problem, the Duc reaches maximum torque at 8000 Rpm, obviously, this needs to come down by a lot, I want to accomplish this by keeping the exhaust runners to the merge-point as short as possible, and use smaller throttle valves than the Duc uses. Camshafts of a smaller Duc engine with the same head casting may help as well.

The coolant openings at the headgasket surface will be welded shut on a vibrating welding table. Then they need a spigot to locate them on the cilinders.

Ducati's have no redline. Motorcycle engines have very light rotating parts, it is hard to compare, but this set up would pull easily to or over 10K rpm. I will need to establish whether I would have to maintain a redline for this engine. The thing is that motorcycles use very small big end diameters to keep the bearing speeds down. I am using a whopping 55mm big end, so far I haven't found any data that will help determine how fast the bottom end can actually/safely turn without cavitation of the oil film in the bearings.

Desmo Animation

It's a lot less work when compared to fitting 911 heads where the camhousings need to be shortened and custom camshafts need to be fabricated. The 911 heads then still have valve springs.

Originally I was looking for aircooled heads ofcourse, but they are not easy to fit, two valve and hard to cool properly. I justify the air/watercooled combination by thinking of the 959 and 962 engines that used this combination. I will underdrive the cooling fan, I have the large cooling fan normally used on the '89 Turbo, but will probably go to an earlier smaller fan. I've actually tried to find the 959 parts (knowing that will be close to impossible, and the new parts are still available from Porsche but would set me back close to 4000 Euro, not counting the alternator), the 959 uses a unique really small cooling fan. Still, I've found the craziest parts in the craziest ways, so if anyone has a lead to 959 parts pls. let me know.

To cool the heads I want to use as few parts as possible, thought of thermo-siphon circulation by mounting radiators higher than the heads, perhaps a mechanically driven waterpump in the fanhousing against the alternator, or driven off of one of the camshafts on the transmission side.

Motorcycle radiators are often curved, perhaps I can find something that would fit in the VW rear fenders. I'm completely new to water cooling, I still have to do my homework on this.

vdubzack February 10th 2010 14:06

Quote:

Originally Posted by wrenchnride247 (Post 73693)
Cool deal. I have a 915, but have not tried it out yet (still have lots to do) I have heard the Berg 5 welds an extension onto the main shaft for the 5th gear. I don't like the sound of that personaly.

A solid main shaft is also availible too.

verbeekb February 10th 2010 15:37

Quote:

Originally Posted by vdubzack (Post 74134)
A solid main shaft is also availible too.

Thanks Zack!

verbeekb February 10th 2010 16:53

Test fitted the 968 CS rear shocks and springs. They will clear the body by far, glad I'll be able to use them, they are too nice not to. Porsche uses these with the 25.5mm torsion bars, so will I.

http://www.karrera.net/Karrera%20Sed...dan%20(10).jpg
http://www.karrera.net/Karrera%20Sed...dan%20(11).jpg

Parts List. Please note that the top bolts are just a few mm too short to be used with the cup brace bushings in my case. I will either shorten the bushings somewhat or use longer bolts. The lower bolts are for use with Porsche alloy trailing arms.
http://www.karrera.net/Karrera%20Sedan/rear-shocks.jpg


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