MSD 8733 2-Step w/Turbo
MSD 8733 2-Step w/Turbo My Lingenfelter just crapped the bed so I bought a MSD last night.
I just read the instructions and this whole rpm must drop 1/3rd lower then the set point to activate has me concerned. I like to build boost on the footbrake against the converter as I roll into the beams, then I have the 2 step activate through the t-brake. Does this mean the RPM's have to be under 2500 for it to activate a 3700rpm limiter? If so I am screwed with this unit as I footbrake it much higher then that.
I just read the instructions and this whole rpm must drop 1/3rd lower then the set point to activate has me concerned. I like to build boost on the footbrake against the converter as I roll into the beams, then I have the 2 step activate through the t-brake. Does this mean the RPM's have to be under 2500 for it to activate a 3700rpm limiter? If so I am screwed with this unit as I footbrake it much higher then that.
Yes, the rpm's must be <2466 for the 2-step to activate if it is set for 3700rpm.
Are you footbraking at a lower rpm than your 2-step set point? If so, could you wire another switch to activate the 2-step prior to footbraking? The downside would be that you would have 2 switches to control at launch.
Are you footbraking at a lower rpm than your 2-step set point? If so, could you wire another switch to activate the 2-step prior to footbraking? The downside would be that you would have 2 switches to control at launch.
Same issue here. One way to by pass it. Activate the 2 step based on a 12volt source aka brake pedal switch. Then you can foot brake it in, then once you grab your button for the trans brake(assuming its also a 12 volt source) send that 12 volt source T'd into the 12 volt activation source of the MSD. When you let off the brake pedal, 12 volts will remain on the 2 step and you will stay on the brake until you release the button. Only downside I see is it will turn on your brake lights aswell as it will feed 12 volt.
Hopefully that makes sense.
Hopefully that makes sense.
you should be able load the turbo enough footbraking without a 2 step until you have the transbrake activated unless your converter is a little too tight. Another option is to get an msd 3 step for 2 different settings (one for footbrake, one for transbrake)
i have no problem loading the car on footbrake, but i do so at much higher then 2/3rd's my launch rpm.
unless i am mistaken and it will allow you to activate it the first time at whatever rpm you want and only causes issues if you wanted to reactivate it down track (obviously i wouldn't)
I think you are misreading the instruction manual, once the 2 step is activated and then de-activated it has to go below the 2/3 threshold to reactivate if the button is depressed again. Its designed this way for the 6 speed cars that run this box that hook it up to the clutch switch. Say you launch at 6k rpms, and you are power shifting and you push the clutch it, it wont hit the 2 step in between shifts.. its sort of a saftey feature. I never had any problem using it in my 6 speed car. Also, on my auto/turbo car, the transbrake power is wired to the 2 step 12v input, so when I depress the transbrake, the 2 step doesnt activate until I hit the pre-set RPM on the box.
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I think you are misreading the instruction manual, once the 2 step is activated and then de-activated it has to go below the 2/3 threshold to reactivate if the button is depressed again. Its designed this way for the 6 speed cars that run this box that hook it up to the clutch switch. Say you launch at 6k rpms, and you are power shifting and you push the clutch it, it wont hit the 2 step in between shifts.. its sort of a saftey feature. I never had any problem using it in my 6 speed car. Also, on my auto/turbo car, the transbrake power is wired to the 2 step 12v input, so when I depress the transbrake, the 2 step doesnt activate until I hit the pre-set RPM on the box.
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You won't need to worry. I had the same one on my turbo car and footbraked it into the beams off the 2 step at 3200-3600 and my two step was at 3800.
It's only when the button is pushed, so if your not pushing the button that the two step is on until you grab your t brake(2 step&t brake on same button) you will not have to worry about the 1/3rd thing.
It's only when the button is pushed, so if your not pushing the button that the two step is on until you grab your t brake(2 step&t brake on same button) you will not have to worry about the 1/3rd thing.
You won't need to worry. I had the same one on my turbo car and footbraked it into the beams off the 2 step at 3200-3600 and my two step was at 3800.
It's only when the button is pushed, so if your not pushing the button that the two step is on until you grab your t brake(2 step&t brake on same button) you will not have to worry about the 1/3rd thing.
It's only when the button is pushed, so if your not pushing the button that the two step is on until you grab your t brake(2 step&t brake on same button) you will not have to worry about the 1/3rd thing.
Same issue here. One way to by pass it. Activate the 2 step based on a 12volt source aka brake pedal switch. Then you can foot brake it in, then once you grab your button for the trans brake(assuming its also a 12 volt source) send that 12 volt source T'd into the 12 volt activation source of the MSD. When you let off the brake pedal, 12 volts will remain on the 2 step and you will stay on the brake until you release the button. Only downside I see is it will turn on your brake lights aswell as it will feed 12 volt.
Hopefully that makes sense.
Hopefully that makes sense.
the only issue I can see would be that the t-brake would then always trip the brake lights (which i don't really think is a "issue"), but if i wanted to fix that i could simply use a diode or another relay.
this is what one of the tech's at msd said and the other said it works the way fbodyjunkie said, it should be here tomorrow so i'll test it out of the box and see.
I dunno but I think wheelsup has the right idea as to how it works.
Another thing about my MSD is that when the car came on the red light was illuminated solid red on the msd box, and when I would press the button my transbrake and two step where on(shifter handle) it would blink. I only think the 1/3rd programming is active while that light is blinking. It's been so long since I used the damn thing, but I think that's how it works.
FWIW I was using the ground wire on the MSD unit to trigger it and not 12v. It was wired in with my Jakes Pro Brake for my 4L80E which worked off ground and I had a diode in between the two. Jakes 80e brake works off the 2-3 shift solenoid so whenever I would shift the car into 3rd or 4th gear and the two step was plugged in the transbrake technically was powered which sent ground signal to the 2 step which made it come on when it went into 3rd or 4th. But only when that circuit was energized did the two step's features work.
Last edited by Fbodyjunkie06; May 18, 2012 at 10:41 AM.
That's weird. I always brought mine up anywhere between 3000-3600 on the footbrake, sat there built 6-7psi, then bumped into the 2nd light, and grabbed the transbrake and the two step would come on where I had it set between 3600-3800.
I dunno but I think wheelsup has the right idea as to how it works.
Another thing about my MSD is that when the car came on the red light was illuminated solid red on the msd box, and when I would press the button my transbrake and two step where on(shifter handle) it would blink. I only think the 1/3rd programming is active while that light is blinking. It's been so long since I used the damn thing, but I think that's how it works.
FWIW I was using the ground wire on the MSD unit to trigger it and not 12v. It was wired in with my Jakes Pro Brake for my 4L80E which worked off ground and I had a diode in between the two. Jakes 80e brake works off the 2-3 shift solenoid so whenever I would shift the car into 3rd or 4th gear and the two step was plugged in the transbrake technically was powered which sent ground signal to the 2 step which made it come on when it went into 3rd or 4th. But only when that circuit was energized did the two step's features work.
I dunno but I think wheelsup has the right idea as to how it works.
Another thing about my MSD is that when the car came on the red light was illuminated solid red on the msd box, and when I would press the button my transbrake and two step where on(shifter handle) it would blink. I only think the 1/3rd programming is active while that light is blinking. It's been so long since I used the damn thing, but I think that's how it works.
FWIW I was using the ground wire on the MSD unit to trigger it and not 12v. It was wired in with my Jakes Pro Brake for my 4L80E which worked off ground and I had a diode in between the two. Jakes 80e brake works off the 2-3 shift solenoid so whenever I would shift the car into 3rd or 4th gear and the two step was plugged in the transbrake technically was powered which sent ground signal to the 2 step which made it come on when it went into 3rd or 4th. But only when that circuit was energized did the two step's features work.
I was playing around with my MSD box last night, and it just seems off. I'm used to the violent reaction my DSM had to the 2 step. Anybody have a vid of their LSX car on the 2 step?
Mine wasn't loud by any means. It was a gentle popping. That was until I played with the timing a little bit and found some tricks to really get it to spool. Then it sounded a bit different.
My Harlan Two step is a lot more violent when it comes on.
My Harlan Two step is a lot more violent when it comes on.
