W. MITTY

I want to go with a wider rear wheel on my 964 Turbo. and I understand the using narrow body rear trailing arms will allow this. Can anyone tell me whether there are any major disadvantages to this conversion? What other changes to the rear powertrain will be required to accomplish this?

Thanks for the help.

BTW, I tried to search for guidance, but all I can find are indirect references, no clear advise

revolution993

shouldn’t be any complication’s the 3.8RS run’s narrow body trailing arms.

Scott Dunavant

The Turbo bearing is $120 and the C2/C4 bearing is $49 Usually Turbo can handle the increased torque/hp

W. MITTY

I wonder if the Turbo bearing will fit in the narrow body trailing arm...from what I understand, the hub and bearing for the narrow body arm is smaller?

budge96

The RS 3.8 93 uses the narrow arms which do require a shorter set of axles other than that I believe you are restricted to a smaller rear disc

...Bert

W. MITTY

Thanks! I'm told that perhaps a 968 rear rotor would work...anyone have any experience with this, or perhaps a part number?

budge96

Perhaps Bill V will chime in with the RS spec but of course you can use the rear C2 disc and perhaps a larger caliper , otherwise I've heard using the larger disc can loose the emergency brake function..Bert

peterpullin

over here in german one guy is in the middle of doing it. main problem is the inner bearing of the axles. they were a porsche motorsport parts and are nla. other diameter than rs or c4/2 so it seems you have to produce shorter axles. or are lucky to find used ones at a dismantlers shop. chance is not that big....

about brakes: you have to use smaller calipers as c4 or 993 did. disks can be used as the rs if i remember right.

so no big deal - except drive shafts.

W. MITTY

I have a pair of shorter axles coming, part No.964 332 024 08. Hope this is the right part. The narrow trailing arms are at Elephant Racing right now being refurbished with the C2 bearings and bushings installed. I'm not sure what difficulty your friend in Germany is having, but hope I don't run into the same thing. Still a little confused about what his difficulty is, can you explain it further?

peterpullin

the guy over here wrote:Hinterachse:

Bei der Hinterachse bin ich noch nicht ganz Schlüssig wie ich vorgehen will. Es gab ja den 964 3.8l welcher zwar die Turbo-Chassis ab Werk hatte, aber trotzdem die schmalen Hinterachslenker in Verbindung mit den 12" ET -20 Felgen.

Ansonsten gibt es die Möglichkeit, die Turbo-Hinterachslenker zu verwenden. Ich habe diese auch bereits hier vor Ort. Das Problem sind hier die Gelenkwellen. Diese sind für die C2/Turbos nicht baugleich mit den C4 Gelenkwellen.

Die Anschlüsse an den Getriebeflansch sind beim C4 mit M8 Schrauben, beim C2/Turbo mit M10 (und grösserer Flansch). Radseitig ist der Durchmesser auf die Radnaben beim Turbo grösser, die Turbo-Gelenkwellen sind auch 1mm dicker.



Das resultiert also in folgendem Problem, ich habe die langen Turbo-Gelenkwellen, welche auch auf die Turbo-Hinterachse-Radnaben passen. Diese Gelenkwellen passen aber nicht auf den Flansch von meinem C4 auf der Getriebeseite.

Gemäss dem Ersatzteilkatalog sind die Jubilé-Gelenkwellen identisch mit den Turbo 3.3/3.6 Gelenkwellen. Es gibt also keine langen Gelenkwellen mit C4-Flansch getriebeseitig. Das würde also bedeuten, dass der C4-Jubilé einen C2 Getriebeflansch im Getriebe verbaut hat.

Weiss dies jemand per Zufall und kann dies bestätigen?



Falls ich die Turbo-Hinterachsschwingen verwenden will kann ich das Problem nur auf zwei Arten lösen.

1. Flansch am Getriebe auf einen C2 Flansch ändern.

2. Die Turbo-Gelenkwelle umbauen. Ich habe gelesen, dass man aus einer C2 Gelenkwelle auch eine für den C4 bauen könnte indem man das C4 Gelenk (951.332.030.00) an der C2-Gelenkwelle verwendet. Kann dies jemand bestätigen dass dies passt? Kann ich mir irgendwie nur schwer vorstellen, die Turbo-Welle ist immerhin 1mm dicker. Falls dies funktioniert, wäre dies die einfachste Lösung, da ich einfach ein Reparatursatz Gelenk kaufen könnte.

Hat hier jemand Tipps für mich?



Ausserdem hat der Jubilé auf der Hinterachse ja andere Bremsen. Müssen diese zwingend umgebaut werden, oder ist es technisch möglich die Standard-C4 Bremsen weiterzuverwenden? Also würden die überhaupt noch passen?

he describes the problem converting turbo with shorter axles. they only were available for non turbo cars. that means thinner and smaler bearings. different screws. turbo m10 all others m8, so it is not exchangable. may be no problem in us. over here you need paiperwork for any part. you can not mount parts without loosing legal use of vehicle.

W. MITTY

^^^^ thanks, I think I understand the problem. I am amazed at the stringent level of care taken in Germany. That makes sense given the seriousness with which the German people take driving

peterpullin

there is always pro and cons. over here it gets crazy in the stupid way. my 91 turbo is a german car. then it left germany for about 8 years and came back. once back it gets new paperwork. they missed out x33. so it is a standard posche 964 turbo now. adding that to the papers is now no longer possible. porsche never made some special paperwork for x33. porsche drove the cars to the next tüv station and got a stamp that time. today this is no longer valid. so you have to unmount x33 male a test for emissions. the big onqe with driving and so on. then remount the x33 and do again. costs are up to 20000 euro. so the women at the „zulassungsstelle“ told me to take a dremel and remove the „s“ from the engine and love the more horsepowers ....

jim dorociak

If you have Speedlines then you are changing both the inner and outer rear rims to fit. How big of a rear wheel were you thinking?? jdorociak@gmail.com. Jim

W. MITTY

I've got a set of Fikse Fuchs coming...the rear will be 18x11, ET+5. I'll put the speediness in storage.

cobalt

I don't read german but I believe your friend is stating he is converting a C4 Jubilee and not a turbo. The flanges all use M10's C2 or turbo the C4 uses M8 bolts. A C2 or RS drive shaft should bolt up to a G50/52 flange. The only differences between the RS and the C2 shafts are they install a roll pin in the opening to prevent grease from leaking out of the opening. New shafts from Porsche are GKN and aren't like the old style. Instead of the shaft being hollow it is solid and has been increased in Dia. I am assuming they increased the dia for added strength since the shaft is no longer hollow. It does weigh more and I found the grease just like the bearings is junk. I open and clean out all the grease from the bearings and axles and repack before installing for longer life. Especially on my track cars. I keep my old drive shafts now so I can rebuild them If I can or buy new and switch out the shafts to the hollow ones.

You could have played with the ET a little.

factory Speedlines ET5 11". I could run a small spacer or wider tire. These are slicks so a bit different shoulder and are a 305. I also rolled the fenders and using a fair amount of - camber.