launch control w/BS3

[jpwalt1987]

i have a gen 1 big stuff 3 system, a tial wastegate and a Th-400 with a brake. i need to figure out how to set it up as far as launch control. basically if i want to launch at 4000 i want to be able to engage the T-brake and stick it to the floor(like a 2 step i guess). i would like to launch it as hard as the track will allow. do i have to use a boost contoller like innovatives or is there another way? not sure about how to go about doing this. any experienced hands aout there? thanks, jeremy walters

 

[V6RACER]

You have to supply 12v to the two step wire in the harness and set the operational configuration (Two Step) to do this. You will not be able to make it work with the CCCI ignition.

 

[jpwalt1987]

well i didnt really want to go to a distributer right now. why will it not work w/ ccci? what other options do i have? thanks, jeremy

 

[V6RACER]

You could use a DIS4 that has a built in two step. I wouldn't recommend it though. Because you don't get a true two step (dropping one cylinder, in order, each rotation). The CCCI drops one coil (which fires two cylinders) per rotation. With that you could have violent cylinder pressures during operation.

 

[turbodave231]

I'm using the BS3 2-step with the C3I ignition. No problems here.....
I'm not currently using an electronic boost controller but seriously considering the Innovative unit.

My BS3 is a Gen 3 sequential, which I beleive drops injector pulse not coil operation to limit RPM.

Dave

 

[Craig Smith]

I'm using the BS3 2-step with the C3I ignition. No problems here.....
I'm not currently using an electronic boost controller but seriously considering the Innovative unit.

My BS3 is a Gen 3 sequential, which I beleive drops injector pulse not coil operation to limit RPM.

Dave

The only way to make a rev limiter work properly and reliably with a C3I ignition is to have multiple ignition control outputs and bypass the signal steering functions inside the C3I module. You need to basically hook straight to the coils, like the DIS-4 does. If you drop a control pulse to the C3I module, it won't know it. It will just fire the coil that should have fired 120 degrees ago. The timing changes 120 degrees each time a control pulse is dropped. Some people do it and get away with it, and I don't know how or why. I do know that some aftermarket C3I modules don't work exactly like the OEM ones do. Maybe that's it.

I would consider it unlikely that any control system would drop fuel for a two-step. How much fuel would you want to pull out when making 20 psi on the transbrake?

 

[turbodave231]

Craig,

I am using a GM ignition module not an aftermarket unit. My ignition module has the typical cam, crank inputs and the same factory outputs.

The BS3 Two step works (and works rather well in my opinion)and it is not tied directly to the coils. If the unit is not dropping injector pulse, how else could it be controlling RPM?

 

[SPOT MY 6]

The GEN1 BS3 does not have a built in 2-step feature, only the GEN3 does. I use the DIS-4 with the GEN1 unit and have factory coils. No problems and very consistent, see vid in sig.

 

[jpwalt1987]

Well, I emailed John Meaney about upgrading from gen 1 to gen3. Cant do it. They use different processors
I will have to sell the gen1 and buy a gen 3, Or go the DIS-4 route. I figured up about $480 to go with a dis-4. Can I use an electronic boost contoller to set a launch boost pressure that is activated when the transbrake button is engaged. Say it is set at 10psi on launch, if I go WOT on the brake would the convertor limit the rpm of the motor or would it just go to redline? How do you guys predict that setup would work? Just exploring all options. thanks jeremy walters

 

[Louie L.]

JP,
The motor will rev to the converter limit. Note: The limit can change based on boost to a certain degree. In other words if you converter flashes to 4 k on the brake with 10 psi on the controller, it could go to 4500k rpm with 15 psi on the controller. In some extreme instances if the motor is making BIG power you could just blow thru the converter on the brake.This method does work but the boost controller has to be figured out and be pretty much dead on.

With that said i have used this method sucessfully with a Innovative boost controller and CO2. When the MSD DIs 4 worked it was very nice .Again when it worked..



If you get rid of the BS unit, look into the XFIs i think youd be happier. I currently use the sequential rev limiter in the XFI as a 2 step and my crane ignition (distributor) as my high side rev limiter.

 

[jpwalt1987]

Louie, I know that stall speed is dependant on torque. More boost, more torque.More fun. :biggrin: I would guess that running up against the convertor would be very hard on it with alot of power too. What do you consider BIG power though? 600? 800? I should be able to run some high nines with the parts I have. I take it that you had alot of problems with your dis-4? What kind of price can an XFI be had for? I would assume I would just need the box and software? thanks for the info. Jeremy :smile:

 

[Nashty]

I tried to get my Gen1 upgraded as I wanted to run coil on ignition. (More on that later...) So I feel your pain.

I use the BS3 Gen 1 box for my rev limiter and have the DIS4 setup. I've never had a misfire problem with my car either. It does seem to eat up coils more often with the DIS though. I have mine wired so when the trans brake is engaged the two step is on and the nitrous is in-activated. When I release the transbrake (assuming the WOT switch for the N20 is closed) the two step drops off and the nitrous flows. I had to wire the relay for reverse polarity to accomplish this. In other words, grounding the trans brake button creates, opens the nitrous circuit (inactivating it), when the transbrake circuit opens, the nitrous circuit closes (activating it). I add this because you may have to do some trickery like this with your boost controller. Your boost controller will be indepent of the two step if you get an electronic one. Some people set the two step higher (which would create too much boost at launch -tires would spin) and then use the e-boost controller to limit boost. That way, there is some lag time between when you launch and the boost comes up. It makes a bit of a softer launch if your chassis can't handle all that power off the launch.

Now onto the coil on plug. Everyone likes the distributor right now. Instead, try the state of the art and order an LS1 BS3 box and use coil on plug. Better spark and you again have individual cyl. spark control (not so with a distributor) and NO chance of spark scatter. At some point, people will switch to this I suppose. I'm not sure why no-one has done it yet except that as far as I know, the BS3 is the only way to do it. XFI might but I simply don't know, I do know it's possible with the BS3. Now THAT would be the way to go. I'm currently watching eBay for some LS2 coils on the cheap. They are supposed to be better than even the MSD coils. Go on, blaze the trail !!

In the mean time, I'll just have to live with the waste spark... :frown:

 

[SPOT MY 6]

I use the BS3 GEN1, MSD DIS4, and MSD boost controller. The boost controller and DIS 2step are hooked to the same transbrake button. The boost controller has a "luanch" boost setting which is activated when I press the transbrake button. I can tell the "launch boost" to sit at 15psi on the brake and shut the DIS 2 step off. The boost will sit at 15psi until I let go of the button. This is sort of like a 2 step except you dont cut coils to stop the RPM. Since the spring in my wastegate is a 15psi spring, the minium boost I can launch with is 15psi. Its a trick setup and works great. However, the video in my sig was only using the DIS 4's 2 step.

I wish I had a 10psi spring though so I can smoothly ramp boost in on the street while street racing on drag radials (traction control). I might buy one and give it a try......