newb trying to build boost with 2 step question
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newb trying to build boost with 2 step question I have a 98 trans am ls1 6 speed with on3 76mm turbo kit installed, 243 ported heads with blower cam. Anyways last time I ran at the track was pretty horrible lol. So I decided to install the msd 2 step to help build boost when I launch it. Got it set at 3500 for right now but it doesn't build any boost at all, my boost gauge (innovate scg1) actually still reads some vacuum. Is there something I'm not doing right?
Last edited by dieselman88; Jun 20, 2015 at 06:02 PM.
I have a 98 trans am ls1 6 speed with on3 76mm turbo kit installed, 243 ported heads with blower cam. Anyways last time I ran at the track was pretty horrible lol. So I decided to install the msd 2 step to help build boost when I launch it. Got it set at 3500 for right now but it doesn't build any boost at all, my boost gauge (innovate scg1) actually still reads some vacuum. Is there something I'm not doing right?
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Yes it reads 0 with engine off. Seems to pull around 15-17" of vacuum at idle. I don't have a vacuum gauge to verify it but when it was getting dyno tuned it matched the tuners readings. The best I can get it to do is 0psi, but when I let out you can hear the bov. How long can you hold the car on 2 step without damaging anything?
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From: Norn Iron
And what rpm would you normally build boost on at high load on the road ?
And no, the wideband will always indicate lean when there is excess oxygen passing through the engine and onto the sensor.
ie any non firing condition of the engine.
And no, the wideband will always indicate lean when there is excess oxygen passing through the engine and onto the sensor.
ie any non firing condition of the engine.
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From: Norn Iron
Ideally yes there would be adjustments to timing and fuel in order to build boost under these conditions.
But if you're using enough launch rpm with some for of basic rpm limiter then it should still be able to build a little. But if he's far below the threshold where it normally builds boost then a basic 2 step offers no chance of building boost.
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I imagine that you might be making 1-2psi of boost at that rpm but once you launch the car it must hit pretty hard. I have a similar setup but no 2step yet. On the road i hit 2psi around 3000rpm with my controller on low.On high i can be at 7psi in 3rd at 3000rpm and full 12 by 3700 and then hold on for the ride.
I dont know how much boost your running but i know mine can be lazy when my controller is low but makes driving around the city easier.
If you dont have a seperate boost gauge directly off the turbo then i highly suggest you get one.This is how I can easily compare what my vac/boost gauge from my map sensor vs my boost controller. I simply bought a brass npt fitting with a barb end and drill/tapped the turbo and directly see what boost is at the turbo vs what the motor gets after the going through the cooler etc.Its handy as there is a drop in pressure.
I dont know how much boost your running but i know mine can be lazy when my controller is low but makes driving around the city easier.
If you dont have a seperate boost gauge directly off the turbo then i highly suggest you get one.This is how I can easily compare what my vac/boost gauge from my map sensor vs my boost controller. I simply bought a brass npt fitting with a barb end and drill/tapped the turbo and directly see what boost is at the turbo vs what the motor gets after the going through the cooler etc.Its handy as there is a drop in pressure.
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The innovate scg1 is a boost/wideband gauge with a built in boost controller. I believe it gets the boost refrence from the map sensor it came with which I have it hooked up to a vacuum block that I have tapped into the brake booster hose. Car is set on 10 psi. Haven't it ran it at the track, just installed the 2 step and was making sure everything was working before I took it back. Seems like it should build a little or at least hear it spool up some. But I'm new to all this so I'm still learning lol
I'd change the source of the boost reference. Just my preference to go directly from the turbo itself and not use the map and the vacuum lines from there. My tuner agreed the sometimes using vacuum t's so close to the map can mess with the readings. Plus the boost controller will be accurate of what the turbo itself is doing and better control. It's working great for me.
As for the mad 2 step I can't comment on. I'm trying not to build much boost off the line as I'm just spinning crazy tire lol.
As for the mad 2 step I can't comment on. I'm trying not to build much boost off the line as I'm just spinning crazy tire lol.
My ebc reference is off my fuel pressure regulator vac line which is direct to intake, nothing else is tee'd to that. That way there's no air "flow" or fluctuations. I feel any boost source other than intake is not accurate for such an important controlling device (wg control) because the compressor side boost is not the same pressure that the engine is "seeing".
Also, i had a problem with my brake booster check valve. I couldn't figure out where my boost was "going",i kept upping wg springs and while learning how to use the scg-1 i was chasing my tail On that one.
With the scg-1,there's no "desired" boost setting. I don't know if all/most boost controllers work this way but you achieve desired boost with your wg spring setting and the duty cycle % setting. The more DC %,the more boost is directed to the top of the wg. The higher i set the gain setting,the harder/faster it reacts to the wg spring setting.
Is this how most ebc's work?
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From: Norn Iron
Most EBC's work purely on a duty as opposed to an actual desired boost target. Which in this day and age is really odd.
But they still do. There may be a small handful that work via targets ( most will still require a base setup with respect to duty though, but after that selecting boost settings is easier )
But they still do. There may be a small handful that work via targets ( most will still require a base setup with respect to duty though, but after that selecting boost settings is easier )
Most EBC's work purely on a duty as opposed to an actual desired boost target. Which in this day and age is really odd.
But they still do. There may be a small handful that work via targets ( most will still require a base setup with respect to duty though, but after that selecting boost settings is easier )
But they still do. There may be a small handful that work via targets ( most will still require a base setup with respect to duty though, but after that selecting boost settings is easier )
For ex.. DC,gain etc.
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From: Norn Iron
Gain is a different variable, and would be much harder to be automated. The process of trying to learn this aspect would almost be self defeating, as the learning process would slow down the ramp, which the gain is trying to speed up.
But the controller should be able to learn control duties required within a few pulls which could then form the base table ( seen or unseeen by user ), without the user doing too much which would then mean all boost is done via targets selected by the end user
It isnt hard to do manually of course, but given modern electronics it really should require no effort from the customer or tuner.
