black98ws6ta

iTrader: (77)

I have the car tuned pe vs. rpm and the car have good a/f on 13 lbs of boost. Is there a setting that is keeping the car from not dumping the same fuel when im on the 2 step? Maybe a setting for the phasing in of the pe table instead of it still referencing maf ? TIA

sb427f-car

How much boost are you seeing on the 2 step? You won't have a full 13#s because you're not loading the engine enough to really create a full load of exhaust. The thing is, while you're on the 2step @ the line, you've got the shaft up to speed and it should shoot straight up once you drop the hammer and come off the line.

black98ws6ta

iTrader: (77)

I had seen several other cars come on on boost much quicker, and develop more boost at a certain rpm. 2 step set for 5000 and it only builds 2 psi. I takes alittle bit and the wideband reads 13.x, I just think its not going into pe, and is not dumping enough fuel.

ABeasst

iTrader: (5)

it wont build boost on a 6spd

NicD

iTrader: (7)

Watch your commanded A/F ratio in the scanner to make sure it's going into PE. The wideband is probably just be reading a lot of unburned oxygen in the exhaust since it's not firing some of the cylinders while on the 2 step. Also what is your timing while on the 2 step?

yes it will

ABeasst

iTrader: (5)

I thought it would only build like 1#

black98ws6ta

iTrader: (77)

I dont think it is going into PE, if it was I would think that the afr's would drop, resulting in a bunch of unburnt fuel spooling the turbo. I didnt tune for the 2 step as far as timing goes, I will check to see what timing it makes. Is there a setting im missing that would keep the car from going into PE while being on a 2 step.

onfire

iTrader: (17)

It will go into PE if you're 100% TPS....possibly at 60% depending how you have it commanded.

67Firebird455

iTrader: (27)

That's strange, I would figure you'd get more than just a pound running it up to 5 grand on a 2 step... I could see it not spooling if you had GIANT turbo on there.

black98ws6ta

iTrader: (77)

Car spools fine under load and is making good power. I have the stock commanded tps vs coolant temp for going into PE. Car just feels like it is not dumping the fuel that it normally would at that rpm, in PE, on a 2 step. Motor is a 408 with junk heads, and a t4 flanged t-88.

hellbents10

iTrader: (10)

When are you commanding PE. I would try turning it down in the TPS range. Usually on a turbo motor I will have something like this.

2000rpm 85%
3000 70%
4000 45%
5000 35%

and so on it will differ from setup to setup.

Also like stated above it will see a lot of unburned oxygen in the exhaust from not fireing all cylinders.

How much timing do you have in those parts of the table and how much are you pulling on the 2 step???

LTLHOMER

iTrader: (10)

To build boost on a stick car, you need to retard the hell out of the timing and add some fuel. Do you have a way of retarding your timing without just fudging your timing curve? If you check out turbomustangs.com, you'll see all the stick cars are running almost no timing in order to get the charge to ignite as its going out the exhaust valve which makes the turbo spool since the heat is right there from the combustion.

Now on an auto car, it's the opposite but it looks like you've got a 6 speed.

sr71

iTrader: (17)

my car would make 5psi @ 5k on the 2-step when it was a 6spd. and it had NO special tuning. a guy on corvette forum ha some sort of resistor wired into his iat sensor that he activates with a switch(could be wired to work with the 2-step). when activated it tricks the iat sensor into pulling timing. he says that this really help build boost on the line.

black98ws6ta

iTrader: (77)

Its a turbo 400 car, with 6 spd computer/tuning. I have had several turbo ls1 cars and they didnt require anything different wise, just slap the harlan 2 step on it and go built boost. I am talking about checking the 2 step in park or neutral, nothing special done to the timing, and I still have to check what timing it runs when on the 2 step. I could see that running a resistor to the iat and pulling lots of timing would help, but I assumed on past expereinces that the fuel in PE for 13 lbs of boost would be enough to make some boost on the 2 step.

LTLHOMER

iTrader: (10)

I'm guessing this particular combo has less cubes and/or bigger turbo(s) than your previous setups...my car fights building boost because it's only 347 inches and has two 66's on it. But we are working on getting it to leave harder by adding timing.

You don't want to pull timing on an automatic.

Do you have a trans-brake? If not, you are fighting a losing battle because to make more boost, you need to increase timing and make more torque, but doing that without a trans brake means you will just push through your brakes and defeat the purpose.

sr71

iTrader: (17)

why don't you want to pull timing on an auto car??? I'm going to need to pull timing to spool the new turbos.

and I agree with Homer, a transbrake is the best thing I ever did for my turbo set up. I couldn't get much boost against the footbrake even on the 2-step.

black98ws6ta

iTrader: (77)

I dont see why it matters if its a auto or a 6 spd when its in neutral or part, the car acts the same as a 6 spd. It builds boost fine on a t brake and fine footspooling it. I have a 408 and a 88, compared to my past stock motor and 76qtq.

qqwqeqwrqwqtq

Yep, as was allready mentioned you need to pull a ton of timing (like bring it to 0-10 total) and you can do that with the iat sensor trick and some adjustments to that table.

I was able to leave with 8-10 lbs of boost @ 4,400 rpm with my LT1.

LTLHOMER

iTrader: (10)

You don't want to pull timing on an auto car...to make the car come up on boost more, you need it to make more torque. A stick car will just rev to whatever you want so rpm isn't a problem. A t-brake does not put the car in neutral. It puts the car in first and reverse at the same time.

Stick - no timing
Auto - add timing until you can leave on as much boost/rpm as you desire. If you can't get to that point, you need to loosen up the converter a little.

black98ws6ta

iTrader: (77)

I have the 2 step on a footbrake, as well as 2 step on the t-brake. I am still thinking my 408 shouldnt have any problem building boost in park or neutral on a 2 step alone, no load from the chassis. I will try taking some timing out of it and see what it does.