relay for tb

Got in a little conversation at the track tonight. T-Bird was giving me fits the last couple of weeks with the transbrake button and not going into reverse all the time. Got pissed tonight and changed to a new Moroso transbrake switch and the problems went away. Had a BS session with the local tranny guy and he asked if i had a relay in that circut for the tb switch and I said no. His reply was put one on it he believes this is why I was fighting with the old switch. To much amp draw for the switch ratings eventualy killing the switch or making them flaky. anyone else experiance this. no delay box as it is a footbrake car.
Steve [img][/img]

richter69 wrote:I have never used a relay for the tb sol, sounds like the switch was not rated for the amp load.

x2 I just use a switch rated for the pull and a fuse in case it needs ....



Randy

^^^^ Got to disagree with the above. Take a read here, I always used the Stop-it and a selenoid . Anytime you use a momentary switch it will build higher and higher dc current the longer it is held, making the transbrake not release properly or act funky. Read this link below. I know a lot of guy's here are going to disagree but whatever, to each his own.


https://www.shogunindustries.com/cgi-bin/ws400CS.cgi?cart_id=1100725025922316&page=products.htm&view_item=101003

^^^^^^^^^^ Like I said to each thier own ^^^^^^^^^^^^^^^ I ran one on the green car for years, cut good lights and never had an ounce of a problem. Biggest thing is guy's think they can ground them to the tranny itself, don't work that way. Needs to be a chassis or (-) post ground.

Travis

TravisRice wrote:^^^^ Got to disagree with the above. Take a read here, I always used the Stop-it and a selenoid . Anytime you use a momentary switch it will build higher and higher dc current the longer it is held, making the transbrake not release properly or act funky. Read this link below. I know a lot of guy's here are going to disagree but whatever, to each his own.


https://www.shogunindustries.com/cgi-bin/ws400CS.cgi?cart_id=1100725025922316&page=products.htm&view_item=101003

Travis, in all honesty, those guys are selling you $.050 in parts for $50.00. I'm not doubting you in any way, and I have a high respect for the stuff you do (that I've seen on the sites)... that said check this out: That little box they sell is merely a surge absorber for those who use TB switches that are not up to the task of handling the "back-rush" of current that is generated when a TB switch is released, and the solenoid shoots back its' load

When any solenoid is de-energized, it fires back its' own voltage due to the collapse of the magnetic field (think condenser), and the return of the "armature", or plunger, which contributes to the muscle in the back-rush. This surge tends to wreak havok in the under-rated momentary switches some use, causing problems stated above. Fabio & Coug are right on, higher-rated switches are mandated.

While I'm nowhere near as fast as you guys, electrical theory/implementation is one of my forte's

http://www.suregripcontrols.com/install_suppress.htm

http://classracer.com/classforum/showthread.php?t=14786&highlight=shogun&page=3

Hope I can help

Using a switch only setup.......
The good is a less complicated wiring harness. The bad is even with the best switch, it will eventually wear out carrying all the current load buy it's self. And the type of solenoid the brake uses also plays a part in the life span of the switch.

Using a relay setup.......
The switch life is increased many, many times using a relay to carry the brunt of the load. But the down side is relays can sometimes be effected by vibration. And just like a switch relays too can wear out from the current load.

Both ways have their drawbacks, it's pretty much a question of which you would rather replace when the time comes. And using a delay box (or not) also probably plays a part. I will say that one benefit of using relays for the brake that is hard to duplicate using just switches is wiring the brake & nitrous together [edit] but I can't remember if the TB current is "pass through" when wired with nitrous or not. (need to look for my wiring diagrams )

Previous owner had it grounded to the trans shield knowing that was not right I had already moved it to a grounding lug on the frame rail. Used a moroso #74123 adj switch and just caught on to it's a 15 amp rated switch. Wonder how many amps the solenoid pulls? I think some delay boxes might have a built in relay? More questions than answers maybe.
Steve