I've been given both opinions....yes and no, if I should use the vacuum modulator for a 10 second bracket car under construction. 470 BB roller, T-400, 4000 stall, 4:30 gears and 32X14 tire. I know the modulator won't even come into play on the track at WOT, but I've been told that without using the modulator, pressure will build to high in the tranny while running in the pits. I'm not even sure what that means My tranny builder has said not to worry about it and that "many race t-400's do not use the modulator". But, I've had more than one racer with T-400 experience tell me to definitely use it. I've seen lots of good advice on this board and thought I would post this question. Thanks in advance for any replies. Jim P
Are you running a manual or automatic valve body? Without the modulator, unless you have a manual vale body it isn't going to shift out of 1st with out revving it way up which is sometimes frowned on coming back on the return lane. Bob H.
My TH400 has manual valve body without a modulator. There is a trans brake solenoid in its place. I have no issues.
I'm running no modulator with a full manual ST400. No issues to report after a few thousand hard street miles.
I run one on mine but I don't run a manual valve body. If you have automatic valve body and delete the modulator it will not shift at part throttle.
I'm using an automatic valve body, no tranny brake. I'll hook up the modulator...and hope I don't get caught by the fuzz testing on my county road this spring. (if spring ever comes this year!) .thanks for the advice and expertise . Jim P
