estrellajon

Great write up cobaltactic!

Turboslut

Shouldn't BBI be able to clarify this for its customers?

Turboslut

Is Petosin and dot 4 brake fluid equally as corrosive? My biggest concern is having a hydraulic failure due to some seal or oring failing due to deterioration by brake fluid.

heliflyer

Quote:
Originally Posted by Cobaltactic View Post
I'm still interested to know if the GT3 spring is a solution to reduce the pedal effort...any updates?

Me too!!

Duckstu

It DEFINITELY reduces pedal effort over the stock turbo spring.

With it in place,.. and a BBI slave,.. and a Sachs 2.5 clutch,.. the pedal effort is 47 lbs for much of the stroke,.. and about 52 at the clutch engagement point.

Where are you located?

Cobaltactic

hmmm, maybe i'll have to get the gt3 spring...i'm finding the pedal OK, but abit less weight on the old toes in stop and go traffic would be nice...

Cobaltactic

supposedly they're both not super great stuff...my understanding is that pentosin is eats rubber, therefore you can't use pentosin in a system designed for dot 4, as it would chew the seals, but you can use dot 4 in a system designed for pentosin. the original pentosin system is the one nuking out, so i have no issues using a dot4 upgrade, such as BBi or a GT2 conversion since they use dot 4 and you won't have the potential for fluid to spill over the clutch reservoir due to the hydraulic assist from the power steering system being short-circuited. if you're concerned about getting hydraulic fluid (whether pentosin or dot 4) all over stuff, i would get the BBI upgrade and call it a day, as long as you're ok with a heavier pedal feel.

heliflyer

A long way from you I think !!
I'm in France!

Cobaltactic

So, I finally decided to try the GT2/GT3 spring (99642308119)...glad i did! the pedal effort i measured was:
- without any spring: 75lbs
- with the stock green spring: 60-65lbs
- with the GT2/GT3 spring (purple): 50-55lbs
Unfortunately, i didn't measure the stock system, with the accumulator to do a full comparison, but i'm sure glad i installed the purple spring...much easier on the legs in stop and go traffic!

PorscheStrong

A belated thanks for your earlier post, which I found extremely helpful and it was a big factor in me selecting the BBi slave for my 997TT. The weights are quite helpful. I found the BBi w/out spring to be a bit intense for my liking; BBi w/ GT3 spring feels just right. I'm thrilled with the result!

BBiAutosport

Thank you for the feedback and everyone else for chiming in!

A418t81

I'm still on the stock spring with my BBi slave and I'm totally used to it now. I don't drive my car daily or in much traffic however. The increased clutch feel and predictable engagement is worth any increase in the effort IMO.

PorscheStrong

FWIW, I didn't feel like I lost predictability or feel when I upgraded to the GT3 spring on top of the BBi slave, but it probably cut the weight down by ~1/3. The result is still quite weighty - more than most cars - but still reasonable and feels fitting for a sports car.

Overall, the clutch feel went from one of the worst I've ever felt (stock) to one of the best (BBi slave + GT3 spring). The improvement in driving experience is significant. I drove it today and was all grins.

A418t81

Yeah sorry I didn't mean in reference to the GT3 spring, but rather that BBi slave itself. I still have my GT3 spring and will install it at some point.

Cobaltactic

you're welcome! i agree, this setup is about perfect...i did notice a slight reduction in pedal feel when going from the stock to gt2/gt3 spring on the BBi setup, but the reduction in pedal effort balances that slight "con" with a much larger "pro", in my opinion.