GTAm

[JohnT]

Quote:

Originally Posted by South Africa Dear JohnT, I can take photographs of some of the GTAm stuff I have however when I have tried to post on the Bulletin Board it does not allow my files to be 'attached' and the site 'complains' that the files are too large. I can send you photographs via e-mail if you like or I can post them in this thread if you can tell me how to overcome the above 'issue'.

[Curtis]

The 911 calipers bolt up to the earlier, narrow bolt center to center alfa calipers. Very rare and hard to find but of the 911 in S form had that ATE
caliper in alluminum.

[RossoGTV4Me]

Those calipers you speak of are really expensive last time I looked. New they were in the thousands I beleive.

Quote:

Originally Posted by Curtis The 911 calipers bolt up to the earlier, narrow bolt center to center alfa calipers. Very rare and hard to find but of the 911 in S form had that ATE caliper in alluminum.

[vintage prep]

You can find those S calipers every month on Ebay for a few hundred $ each. Keep in mind they suck!!. The Ate aluminum calipers are known to flex, thats why most Porsche racers dont use them. They work well enough on the 1200lb 906 Porsche flexiflyer which they were originaly designed for, not so well on a 2000lb car.They sure look good though. If your vintage racing, you would want the steel body calipers for maximum performance.

[Curtis]

I'm pretty sure we are not talking about the same calipers. I'll try to look up the Porsche application and numbers for those that work.

The 71 or so Porsche ATEs in iron, as rebuildable cores are worth upwards of the $200 each you reference. I sold a pair of rebuildable alloy S calipers (on ebay) last year for $1000. Also, the alloy caliper is an exact replica of the iron one, and so the iron unit should have no stiffness advantage at all. The 911s weigh in at about a ton, have more tire than most alfas, and those guy don't have an problem with them. I'd venture a guess that any problems encountered on an Alfa occurred with a spindle requiring a poorly designed and thus flexible brake caliper adapter.

[RossoGTV4Me]

I think both of you are talking about differen't calipers. The original GTAm calipers seem to be the ones Curtis is taliking about (the ones in the pictures I provided previously) I beleive...will wait for further clarity, but I beleive they are at least $1k each which leads me to beleive they are the ones Curtis is descriping.

I happened to find another picture, unfortunatly not a good one of the caliper.

Quote:

Originally Posted by Curtis I'm pretty sure we are not talking about the same calipers. I'll try to look up the Porsche application and numbers for those that work. The 71 or so Porsche ATEs in iron, as rebuildable cores are worth upwards of the $200 each you reference. I sold a pair of rebuildable alloy S calipers (on ebay) last year for $1000. Also, the alloy caliper is an exact replica of the iron one, and so the iron unit should have no stiffness advantage at all. The 911s weigh in at about a ton, have more tire than most alfas, and those guy don't have an problem with them. I'd venture a guess that any problems encountered on an Alfa occurred with a spindle requiring a poorly designed and thus flexible brake caliper adapter.

[RossoGTV4Me]

Rear calipers.

Quote:

Originally Posted by Curtis I'm pretty sure we are not talking about the same calipers. I'll try to look up the Porsche application and numbers for those that work. The 71 or so Porsche ATEs in iron, as rebuildable cores are worth upwards of the $200 each you reference. I sold a pair of rebuildable alloy S calipers (on ebay) last year for $1000. Also, the alloy caliper is an exact replica of the iron one, and so the iron unit should have no stiffness advantage at all. The 911s weigh in at about a ton, have more tire than most alfas, and those guy don't have an problem with them. I'd venture a guess that any problems encountered on an Alfa occurred with a spindle requiring a poorly designed and thus flexible brake caliper adapter.

[JohnT]

So, is it safe to say that the Porsche (ATE) "M" caliper and "S" caliper are the same in dimension and differ only in material construction and weight? or are there other tangible differences?
It sounds like they are similar enough (help me out here folks!) to the GTAm calipers whereby they could be made to work with the 13x8's without monumental effort?
I apologize if I am being boneheaded on all of this but......
1) I am no mechanic by any stretch of the imagination (I wouldn't be doing this work myself)
2) I'm having a hard time visualizing some of the issues.....I hear reference to the need for a lower profile caliper to fit the 13x8 wheels....
I think I need an "Alfa Brakes and Uprights for Dummies" book....anyone got one!?

-JT

[vintage prep]

Yes, they are essentially the same. The aluminum body calipers are slightly bulkier (thicker forging), caliper bolt pattern is same (3.5") caliper offset will be different depending on exact model/disk thickness (solid/vented), and the piston size may be different. S calipers are for 18mm (I think) vented only with forged one piece caliper housing. Wish I could remember GTAm disk diameter (10"?). BTW the "M" caliper is originally from a Mercedes model, and was quite common in foreign car junk yards.

[JohnT]

Paul and all-
Thanks again for all of the info and knowledge that you have supplied. You all have been very helpful.....AlfaBB rules!
Keep the info coming!
I promise that once this project is complete (probably Spring/Summer '07 I will have lots of pics, stories of the resto process and some in-car video

-JT

[vintage prep]

Just noticed Porsche iron "remanufactured" Ate calipers available at Rock Auto on the internet for about $50. BMW is the same (1980 320i). These (BMW) have the larger pistons and pads which work well for vintage racers.

[JohnT]

Thanks Paul. Much appreciated

-JT

[just peachey]

Just to bring you all up to speed with my project, I recieved my shell back from the painters on December 22, 2006. Assembled the works during the vacation, ran it on the dyno on Tuesday last week it made 155 hp on the wheels from a 2000cc ts engine with Nissan Ditributor, local (SA) cams, local ignition system. I took it to open practice at the Zwartkops Raceway, near Pretoria, South Africa for a run 4500rpm, max 5000rpm feels very strong compared with my other cars, some teething problems with the German brakes (BMW calipers and Merc discs) !!!!!!!!!!!! But I am extremely happy with the outcome, what a head turner. I will post some pics when I figure that one out.

[Rubel]

Hi Just Peachy

Sounds cool. Are you going to be racing at Zwartkops on Saturday with David Piper and all the guys? I'm in the process of preparing a GTA replica to race in the Legends series.