2step Timing Based vs Fuel

[MN C5]

I have very little knowledge about two steps. And after reading that the new COS #5 will have a fuel based 2 step I've got a couple of questions

1. Wouldn't a timing based 2step be better for a turbo?

2. Is there a 2 step for our motors as a add on product out there somewhere now?

My TQ converter is to tight for my rear turbo so I'm looking to build some additional boost down low. I'd rather not change converters as the last 2 blew up and this one seems to be holding up. Right now I can't get the brakes to hold the truck after 1800 rpms and I've only got a pound or two of boost there.

[turboberserker]

Dennis, have you tried the SyTy Shuffle to build boost?

Throw it in neutral, rev it up and as the RPMs come down, mash the brake pedal with all your might. The pedal should drop more with the extra vacuum. I can hold it to 5-6psi using this (and haven't done a launch since I upgraded the brakes, so maybe a bit more now), but have a little smaller turbo that you.

What's your stall now? Does it have a turbo stator?

I vaguely remember Harlan's two step being timing based but am not sure at all. I would also think timing reduction is better for FI.

[MN C5]

Erik, I did try that but the brakes won't hold. Just don't have enough slip in the converter. Chuch set me up with this TQ converter for the Radix 427 which it worked great for. I did wrap the exhaust from the headers back and it looks like that gave me another 2lbs of boost at the same rpm.. but its still not enough I need to find a way to drop the timing to get the EGT up...

I'll have to search that out (Harlan 2 step).. thanks for the tip

Dennis

[MN C5]

I'm using Custom OS #3.. and want a two step that removes timing.

I've disabled

{B5905} Catalytic Converter Light-off Vacuum Disable
{B5906} Catalytic Converter Light-off Vacuum Enable

Zero'ed the values in
{B5901}

Applied the same values in the burst knock table at -40 as 60 and 80c

{B0109)Blend ECT w IAT set to NO

So that being said could I use {B5945} Cold engine Noise Reduction to pull timing if I fool the ECM into thinking that the ECT is -40 via a switch? Using a factor of =_>1 in {B5946} ?

Or will tricking the ECM into thinking ECT is -40c throw a monkey wrench into everything.

Dennis

[MN C5]

Anyone? TTT

[turboberserker]

I think Jim messed around with changing his timing in a similar way. Of course, he has the megasquirt doing his fuel so he could get away with it side-effect free, but he put a pot on his IAT sensor line and got +6 timing to -4 timing by spinning the pot (I think those were the range values -- its been a long while).

You might be able to do something similar with a switch that takes the ECT sensor volts to 0? I think that will side effect you, but if you find all the areas that -40C will screw up the tune and set 'em to the 2-step values I think it should work.

[MN C5]

I think it might be a good weekend project for me