Winter Projects
11-16-2002, 03:00 AM
#1
Rennlist Member
Thread Starter
Winter Projects
All,
My early '90 C2 (96LS450800) comes off the road next week for the winter and I am planning out my possible projects. I am looking at the springs, shocks and rear brake calipers as potential targets, but after going thru the archives I have not been able to sort out some questions around the differences in the 89/90/91 models that might affect my parts requirements:
1) I want to replace the single piston calipers on the rear (964 352 425 03/05) with dual piston models as on the C4 and 92+ C2 (928 352 421/2 02). Is this a bolt-on change or are there other considerations?
2) I understand the US suspension differs from other models in some areas. Are Canadian 964s the same as US or not? (For example I have seen comments that the stock C2 suspension is higher on US models than European but what makes this so?).
3)I want to change the springs for a lower stance. Are the lower springs sold for '90-94 C2s suitable or is my early '90 car "special"?
4) I may or may not change out the stock Boge shocks but if I do I want to be sure that the stock or any shocks I buy work with a 1.2-1.5 inch height reduction. Will any Bilstein/Boge/Koni advertised for the '90 C2 work?
Lots of questions but I appreciate any feedback.
Regards,
Jim
"C2-4FUN"
My early '90 C2 (96LS450800) comes off the road next week for the winter and I am planning out my possible projects. I am looking at the springs, shocks and rear brake calipers as potential targets, but after going thru the archives I have not been able to sort out some questions around the differences in the 89/90/91 models that might affect my parts requirements:
1) I want to replace the single piston calipers on the rear (964 352 425 03/05) with dual piston models as on the C4 and 92+ C2 (928 352 421/2 02). Is this a bolt-on change or are there other considerations?
2) I understand the US suspension differs from other models in some areas. Are Canadian 964s the same as US or not? (For example I have seen comments that the stock C2 suspension is higher on US models than European but what makes this so?).
3)I want to change the springs for a lower stance. Are the lower springs sold for '90-94 C2s suitable or is my early '90 car "special"?
4) I may or may not change out the stock Boge shocks but if I do I want to be sure that the stock or any shocks I buy work with a 1.2-1.5 inch height reduction. Will any Bilstein/Boge/Koni advertised for the '90 C2 work?
Lots of questions but I appreciate any feedback.
Regards,
Jim
"C2-4FUN"
11-16-2002, 12:57 PM
#2
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Rennlist Member
Rennlist Member
Jim, Nice list of worthwhile upgrades. I'll share what I know and maybe someone else can fill in the blanks:
1) 4-piston caliper to the rear is a straight swap, according to this <a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=4&t=000138" target="_blank">post.</a>
2) I don't believe the stock suspension parts are different between US and ROW 964's--Euro RS parts are indeed different, however. The big difference is the US ride height mandated by law. I'm not sure if a definitive answer is necessary, though, since you'll be switching them out anyway, right?
3) Lowering springs can be interchanged throughout the 964 model years. It is the shocks which are different. Cars produced 11/90-on have a different rear strut mount than the pre 11/90 cars to accommodate the new 964 cab top.
4) Change the shocks, especially if your car has >50K miles on the clock. These jobs amount to 8-10 hours of labor for installation, corner balance and alignment. As for which shocks, Bilstein and Koni are the two to look at for a street car--just make sure you don't buy their racing products.
I'd encourage you to take your time, do some research and understand the variables relative to suspension changes. Do an archive search using words like "lowering springs," "Koni," "Bilstein," "H&R" or "Eibach." It's a very expensive upgrade, so make sure you read as much as possible before taking the plunge.
Good luck.
1) 4-piston caliper to the rear is a straight swap, according to this <a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=4&t=000138" target="_blank">post.</a>
2) I don't believe the stock suspension parts are different between US and ROW 964's--Euro RS parts are indeed different, however. The big difference is the US ride height mandated by law. I'm not sure if a definitive answer is necessary, though, since you'll be switching them out anyway, right?
3) Lowering springs can be interchanged throughout the 964 model years. It is the shocks which are different. Cars produced 11/90-on have a different rear strut mount than the pre 11/90 cars to accommodate the new 964 cab top.
4) Change the shocks, especially if your car has >50K miles on the clock. These jobs amount to 8-10 hours of labor for installation, corner balance and alignment. As for which shocks, Bilstein and Koni are the two to look at for a street car--just make sure you don't buy their racing products.
I'd encourage you to take your time, do some research and understand the variables relative to suspension changes. Do an archive search using words like "lowering springs," "Koni," "Bilstein," "H&R" or "Eibach." It's a very expensive upgrade, so make sure you read as much as possible before taking the plunge.
Good luck.
11-18-2002, 05:30 AM
#3
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Lead Rennlist
Technical Advisor
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Lead Rennlist
Technical Advisor
Rennlist
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Dear Jim,
Canadian 964s in the suspension area are the same as US models. They can differ in other areas though but we won´t go into those areas right now because they do not affect your projects.
US and European suspension components are certainly different. PET in this area is not always accurate either. However I can tell you that a US spring of different dimensions to a ROW spring yet they carry the same part number. They have different vendor numbers. A lot of research has gone into this subject and is reviewed in my book.
Lowering combinations. I use Eibach 964 RS straight springs. Not progressives. They are mounted onto the Koni sports adjustables struts and rear shocks specifically manufactured for the early 964s only. 89 and 90 and early 91 model.
years.
You can still get the rears in the USA but stocks are low. Part number 8241-1104Sports. The fronts are very hard to get if not impossible. However you can use the Koni replacement insert and install this into your existing front strut. This takes a shop to do for you though. Involves cutting and welding the strut. Works well I have seen a couple done. The correct Koni built for the job is p/no 8741-1216Sports.
I do not recommend you use lowering springs with original struts and shocks. This has always been my point of view. Save up the extra pennies and do the job properly.
You will also require a corner balance and wheel alignment after doing the job. Please also ensure that all new parts and their part number are correctly recorded. Ensure before the job is started that a ride height check is carried out and the original heights are recorded. Do this again after the job is carried out. Record new heights under originals. Very valuable tool for troubleshooting any problems.
All this alignment, balancing and ride height work should be carried out by an expert. If you are that expert and have a nice level area in which to work terrific. I also recommend you have on hand the correct figures for torqueing things up. Therer are different torques for pre and post rear suspension revision.
What I strongly recommend is that you build up your own mod kit. Get the parts in, make sure they are what you ordered and make sure all the little fittings needed have been provided. When you have a complete kit then install it.
Ciao,
Adrian
911C4
Canadian 964s in the suspension area are the same as US models. They can differ in other areas though but we won´t go into those areas right now because they do not affect your projects.
US and European suspension components are certainly different. PET in this area is not always accurate either. However I can tell you that a US spring of different dimensions to a ROW spring yet they carry the same part number. They have different vendor numbers. A lot of research has gone into this subject and is reviewed in my book.
Lowering combinations. I use Eibach 964 RS straight springs. Not progressives. They are mounted onto the Koni sports adjustables struts and rear shocks specifically manufactured for the early 964s only. 89 and 90 and early 91 model.
years.
You can still get the rears in the USA but stocks are low. Part number 8241-1104Sports. The fronts are very hard to get if not impossible. However you can use the Koni replacement insert and install this into your existing front strut. This takes a shop to do for you though. Involves cutting and welding the strut. Works well I have seen a couple done. The correct Koni built for the job is p/no 8741-1216Sports.
I do not recommend you use lowering springs with original struts and shocks. This has always been my point of view. Save up the extra pennies and do the job properly.
You will also require a corner balance and wheel alignment after doing the job. Please also ensure that all new parts and their part number are correctly recorded. Ensure before the job is started that a ride height check is carried out and the original heights are recorded. Do this again after the job is carried out. Record new heights under originals. Very valuable tool for troubleshooting any problems.
All this alignment, balancing and ride height work should be carried out by an expert. If you are that expert and have a nice level area in which to work terrific. I also recommend you have on hand the correct figures for torqueing things up. Therer are different torques for pre and post rear suspension revision.
What I strongly recommend is that you build up your own mod kit. Get the parts in, make sure they are what you ordered and make sure all the little fittings needed have been provided. When you have a complete kit then install it.
Ciao,
Adrian
911C4
11-19-2002, 02:04 PM
#4
Rennlist Member
Thread Starter
Thanks Joey and Adrian for your useful input. I am fortunate to have a nice heated workshop with room to do almost anything (including pull the engine and put it on a stand to work on as I did last year). After the longest, sunniest, best-weather-for-driving summer in 20 years my car is now parked and waiting so I am, as suggested, assembling parts and information for these projects. How much I get done over the winter will of course depend on time, money and of course, the the all-important spousal consent!
Regards,
Jim Grant
"C24FUN"
Regards,
Jim Grant
"C24FUN"