mzgp5x

Observation:
About a year has passed since I added an ext crankcase vac system.
I had problems with hot starts (Eng temp below 180*F when hot).
Thought it was the starter, but the Summit high torque starter has similar symtoms of high application load. I interlocked all other electrical acc equipment off selection for diverting maximum current to starter circuit.

Car runs strong. The ext Vac pump has helped much w/ increase in perf.

Theory:
So, my next thought is the external Vac pump system (1/3 atm vac) has reseated the piston rings improving compression. (I have not run a leak_dwn test yet).

Other mods:
I also resized the bypass valve springs holding more boost(~14psi).
Drive setup is 7.6" to 3.4"pd. (4.44:1 gear head)
Checked all ext drive fo excessive prevailing torque (looks OK).
Checked all wiring to starter (OK).

App... 97ss 383-D1 MM6.

Comments/ Thoughts welcome.
Thanx.
B.

Bersaglieri

Which setup did you use?

-Dustin-

mzgp5x

GZMS VP103 crank driven pump. Custom mount to Rt side Mtr-compartment rail.
Fabbed my own vac reg set @ (1/3 atm)
Designed/ fabbed a centrifugal air receiver w/ ext oil re-circ to lube pump vanes for street use.
Crank drive machine by myself.
Moved rad forward & down to provide pump and drive clearance.
My own design except for GZmotorsports pump and some plumbing components.
http://s306.photobucket.com/albums/nn244/mzgp5x/

WS6 TA

What picture are we supposed to be looking at in that link?

What pulley sizes or ratio are you using for it? How much vacuum are you seeing?

mzgp5x

http://s306.photobucket.com/albums/n...p%204th%20gen/

1/3 atm, 10"Hg, 5psi vac.

87Aerocoupe

Nice do you drive your car on the street or is it a track only car, can you provide a list of parts, prices and part numbers?

mzgp5x

Street driven. Not much track use due to expense, and, don't have friends. The pump from gzmotorsports.com. A VP103 unit (not offered any more, but replaced with a VP104n). Cost of pump is $380.
Pulley $60+35_crank. Belt $25_Napa. Hose $35 Enco. Fittings $85. I made most of the parts myself from stock purchased from Enco Mfg.

I also made the pump receiver from 3 1/2" exhaust pipe experimenting (sorry no pics). Fits in the bumper up front. The Gzms oil receiver was to large and a poor fit in the 4th gen F_body motor-compartment (MC). Did not work well with the oil re-circ mod. I think works better (centrifugal design).

Also, made the vac regulator. The Gzms Reg units did not fit well in F_body MC pre LS motor. Reg is designed for 1/3 atm (opens @ 5psi vac). I used Gzms design stats for the design.

For the street, you need the oil re-circ to lube the pump vanes. Working for 2 years now. Pushing 12 to 14 psi will cause alot of blow-by and pressure down_low. Bad for seals (rear & front). Lots of leaks. Now, no leaks @ all. Sorry for long rant. B.

9C1'Stangkiller

Have you checked for voltage drop across the battery cable, or taken a resistance reading of said cable?