DonnieShort
Who's Next?
- Joined
- May 27, 2001
TurboDave said:Excuse me for saying so, but what FlyinGN said about holding "plenty" of boost really doesn't mean much. After all, he didn't specify any amount at all. Maybe 5-10# is a "lot" or "plenty" for some.
Holding boost on the line is near the top of my priority list, as it is with many other that really want to optimize ET and MPH, and need a good launch to do it.
Personally, if I can't hold 15-20# on the line then I would never give up my PM.
BTW, for those that mention it, Just because Pontiac didn't use the PM, doesn't mean a thing. There were reasons why they didn't, and unless anybody knows for sure why they didn't, speculating on why is pretty useless, after all.
Vacuum brakes just aren't "the hot ticket" on boosted (epsecially turbo'd) applications.
On most mild mannered street apps. it's fine, but when there's going to be a lot of boost used, or boost over a consistently long period of time, vacuum brakes would be a dangerous detriment.
Probably why Ford still uses the HydroBoost system on their Powerstroke diesels. Lots of boost and under boost virtually all the time.
If I didn't ever take my GN to the track, vacuums would probably be fine also.
I switched to vacuum brakes about 3½ years ago and I would never go back to the pm set up. I bought Red's conversion kit and there has never been a minute's trouble out of it. I have the usual braking mods, S-10 wheel cylinders, large brake shoes ( I get 2 sets and use the larger ones out of both sets ). I have changed my set up ( I rebuilt my motor over the winter, spring, and summer, lol ) but with my old set up that consisted of a PT61 Ptrim, FMIC, 50, vigilante n/l 0 pump, T+ and extender, all the bolt on stuff. I can hold 15-20 psi on the footbrake at the lights all day long. Mid 1.5 60' times on slicks and high 1.6's on dr's. This is an 11.40 car with the previously mentioned set up. Don't know why some people don't have good luck with the vacuum set up. I was worried about the potential of not being able to build the boost I'm accustom to at the line, but it holds the same if not better than the pm. If the braking system is in good working condition and up to snuff, you shouldn't have a problem at all with the vacuum set up and still be able to launch at the track like you want.