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02WS686GN

GM EFI Founder/Editor
Joined
Jun 11, 2004
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359
Ok, I don't even know how to ask this and you might think I'm a douche bag after this, so hear goes anyway, lol. I'm new to the turbo Buick scene (well, kinda) I got my GN off of my dad which he's owned since '89. It needs a ton of work, but as I restore it, I plan on modifying it a bit. I'm having import tuner people I know rave on about this 2 step malarkey. Does anyone in the TR world have one of these? A cousin of mine had a 1st gen TSi Talon with one several years back. I'm totally new to the world of turbos and I'm still learning basically how they work in general. From what I gather, it helps your turbo spool a lot faster reducing lag. Let me know what kind of info you can offer on this and if it's something to even look into. Thanks guys (and gals) :biggrin:
 
The only 2-step I have heard of is a 2-step rev-limiter. The first is a lower setting for a burnout and the second for the 1/4 mile pass. That wouldn't have any effect on spool time though. Anybody else ? :confused:
 
"2 step" (try not to sound like a ricer please) is used for 2 reasons: consistent burnouts and consistent launches. Basically, its an ignition cut rev limiter at low rpms. This means that it has the ability to create load, which allows the turbo to spool up a bit easier. Many people have them linked to a trigger button of some sorts, such as the brake pedal and/or on the trans brake.

Most of the aftermarket computers for our car has a built in launch control feature. However, the MSD Digital-6 will give you a launch control feature aswell.

If you have a street car, you really dont need it. Its you will track the car alot, it will come in handy.

Im sure others will chime in.
 
Oh God, don't mistake me for a ricer, please!! lol. Whats the real term for it then, if 2-step isn't it? Thats all I hear from the douche ricer kids..
 
2-step is not a ricer term. I've been intrigued by it also on a turbo car. All of my camaro buddies use them on their stick shift cars for launching. Works like an adjustable rev limiter that is activated by a switch or button. When you activate the switch it sets the rev-limiter to whatever rpm you want to launch at and when you deactivate the switch the rev-limiter goes back to the other setting. Say you want to launch an ls1 car @ 5000 rpm but your redline is actually 7000. You can set the low side chip to 5000 and launch the same every time without having to wtch the tach or feather the gas.

I want to know what effects it has on spooling a turbo car off the line either against the foot brake or a trans break. I've heard it will help spool up but I would like to know how.

Steve
 
It is so popular with the import scene because many of the turbos are manual trans cars. They can't load the driveline like an automatic does to help spool-up. The 2-step usually works by pulling spark which can leave the exhaust a little rich which then burns in the exhaust helping the turbine speed up. On an automatic the load is created by straining against the converter and burning more fuel that way to keep turbine speed up. As long as you can brake torque to the psi that you want to leave at, it will not help spool-up. (10 psi is 10psi. The turbo is already spooled.) If you can't spool off of the footbrake then your converter probably needs to be better matched to your combo. It can help with consistent launches provided traction is available but I think a good driver can be just as consistent without one.
 
Not to hijack this thread or anything: But- Is there any such thing as a boost controller that would allow one to dial in a launch boost(of say 5psi) and then go to full boost after the hook?
 
rodman99999 said:
Not to hijack this thread or anything: But- Is there any such thing as a boost controller that would allow one to dial in a launch boost(of say 5psi) and then go to full boost after the hook?
Click to expand...

Sure there are. They are, by their nature however, very expensive.
And one must remember, to be able to dial boost down to such low levels, your wastegate device must have a spring pressure no higher than the lowest launch boost you desire to set.
That dictates an external type gate, because the integrated (stock style) gates that most of us run have at minimum a 12# srping (that's your minimum boost then).
And no, it's not as simple as putting a 5# spring in a stock actuator. There's not enough dynamic range in the "internal" style boost control systems. If you started with a 5# spring your max would only be about 12#, maybe 15-17 with dual solenoids.
 
TurboDave said:
Sure there are. They are, by their nature however, very expensive.
And one must remember, to be able to dial boost down to such low levels, your wastegate device must have a spring pressure no higher than the lowest launch boost you desire to set.
That dictates an external type gate, because the integrated (stock style) gates that most of us run have at minimum a 12# srping (that's your minimum boost then).
And no, it's not as simple as putting a 5# spring in a stock actuator. There's not enough dynamic range in the "internal" style boost control systems. If you started with a 5# spring your max would only be about 12#, maybe 15-17 with dual solenoids.
Click to expand...

I'm using the RJC controller now. What I was wondering was if there might be some sort of two stage timer that would allow for two controllers, one set for 5psi and the other for my 20psi. The unit would then switch the boost source hose between the two at the preset point(time) after launch. I've access to the solenoid valving/Y hose connector/etc., but would rather not have to use a switch in the cockpit to choose the point at which full boost is applied. The idea would be to eliminate the inconsistancy of driver input. Just an idea that I think my have some merit:rolleyes: .
 
corsair231 said:
It is so popular with the import scene because many of the turbos are manual trans cars. They can't load the driveline like an automatic does to help spool-up. The 2-step usually works by pulling spark which can leave the exhaust a little rich which then burns in the exhaust helping the turbine speed up. On an automatic the load is created by straining against the converter and burning more fuel that way to keep turbine speed up. As long as you can brake torque to the psi that you want to leave at, it will not help spool-up. (10 psi is 10psi. The turbo is already spooled.) If you can't spool off of the footbrake then your converter probably needs to be better matched to your combo. It can help with consistent launches provided traction is available but I think a good driver can be just as consistent without one.
Click to expand...

Assuming you are correct, that is what I was looking for.

Steve
 
So, we're say nay against the "2 step" ? Just get a boost controller instead then, unless I want an all out track car is basically what the verdict is? My goal is very low 11's, high 10s. If it some how goes faster than that, then it does. But I'm building a 100% street car here that'll also look right at home at a car show too..
 
02WS686GN said:
...... I have no clue on where to buy one or how to install it or anything. Are there any drawbacks to having one, like decreased turbo/engine life?
Click to expand...

Yes, there is a big "drawback" with a 2 step on a Buick with a coil pack. :(

Since you interrupt the spark and not the fuel, it is firing excess fuel on the exhaust cycle which can, and does, cause damage. MSD states this in their documentation.

This is a major reason to go with a distributor, or a coil-on-plug set up. Both of these also require a FAST or similar aftermarket computer.

So if it is a street car primarily, then 2 stage electronic boost control is a good way to go. Boost controllers work best with an external gate, but we have also used them with a stock type actuator with good results. Main purpose here is for consistent launches, not quicker spooling.

The new AMS-500 is a 2 stage controller, just released only a month ago, and shows great promise. We just installed the first one and will try it at the track tomorrow.

For about $350 from Cal Hartline, the AMS-500 offers a lot of performance for the money:)
 
go with what your running.. you don't need one. i have had good luck with timing my spooling up right at the time the light turns green :)
 
Just wanted to give a follow-up from our track experiences yesterday.

The AMS-500 worked as advertised with launch boost for stage I, and the desired target boost with the stage II setting. The important thing, especially with a new product like this, is to have the proper tech support.

We had to call Cal from the track as the instructions were not clear on a setting procedure, and he gave us a simple fix so we could have it working properly - thanks Cal!:biggrin:

We also had our first GN done with a coil-on-plug set up using the FAST system out for testing. All I can say is that we will probably not doing distributors in the future.:eek:

From the data logs and track times, we could see performance was much better than the stock coil pack. This is a low 11 sec. GN with many previous track visits, so we know it well. It has just minor upgrades with a TE-61 turbo, and is a street car with working AC.

We have 2 GN's waiting for the COP conversion, one a 10 sec. street driven car, the other a 9 sec. race car, both that need to utilize the 2 step feature of the FAST system.

There is no way to be competitive in most race programs W/O a 2 step and boost control.:)
 
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