chiaj144

iTrader: (4)

Have you data logged your launch? I have the same problem with my car. I can get it to build 9psi on the brake but the car won't pull until well after the 60'. My best 60 was a 1.8. I have never had a transbrake before or fuel injection for that matter so I was expecting more. I found in my data log that when I get on the brake my afr's are dropping into the low 9, high 8 area. I think it's something to do with the tps rate of change adding fuel but I'm not sure yet. Just trying to give you other options to look at before you pull the converter out.

mike13

iTrader: (27)

Once my car shifts to 2nd it hits hard!!! My afr's are 11.0-11.5 in the 60ft , I appreciate the reply.

MIGHTYMOUSE

iTrader: (59)

my yank has never let me down, its a 3400 and footbrake high 1.5's with 364ci and a 91mm turbo 1.29 on t/b and 32mph out the back door unlocked.

you want to make engine hp at the line, stock tune around 0 boost should be plenty fine.

mike13

iTrader: (27)

sounds like I need the converter looser down low and tightened up on the top end.

buick_lsx

MM, are you saying its better to leave with 0 boost? I thought it was better to leave with boost but I'll try anything to get my car to launch harder lol

hellbents10

iTrader: (10)

I think he is referring to the tune up at 0 psi being spot on. Tune up is key coming into boost and building boost. For example, if you have 15 degrees of timing and your AFR is under 12:1 on the line its going to be a pig.

MIGHTYMOUSE

iTrader: (59)

exactly. agressive such as an n/a tune

buick_lsx

ok, i can leave on 10 psi on the foot brake and only get 1.65 60' my car is a slug

MIGHTYMOUSE

iTrader: (59)

is your converter revving to the moon? may be blowing thru it

buick_lsx

Dropped 900 rpm shifting at 6600, it will go 5200 on the tb and flash to around 4300-4500 from a roll

buick_lsx

Footbrake around 3200 before it pushes

mike13

iTrader: (27)

exactly the type of info I'm looking for, my tune goes rich before I go into boost, would the best way to correct that be to raise when it goes into PE?

Sarg

iTrader: (6)

Should read a little lean if it is dropping spark. Unburnt fuel going through the exhaust will not register on the wideband.

Sales@Tick

iTrader: (3)

You need to add timing while your car is commanding the AFR you're seeing while trying to spool on the footbrake in your tune.

Then as your ECU commands a progressively richer AFR as KPA rises start pulling the timing out during this drop in AFR. Once you get the turbo going at about or around 2-3psi you can pull it back out and have it at the timing you plan on running down track.

There is a table in HPtuners that allows you to do this. You will need to data log first and see what AFR you see when you're trying to spool on the foot brake first. Once you can get the turbo going on the foot brake. Then check in your boost enrichment table and figure out what AFR(fuel multiplier coefficient) your commanding at 2-4psi of boost and have the timing you've added as you were transitioning from vacuum into boost brought back out progressively as you hit 2psi and have it all back out by 3-4psi.

You'll probably want to start adding around 5-7* at first and see how that works for you. Normally 10-12* works best and allows for the quickest spool possible so you're not sitting there forever super heating your trans fluid.

It would look something like this while attempting to spool on the footbrake at the line:
Air Fuel Ratio

1)13.2:1 2)12.8:1 3)12.6:1 4)12.4:1(boost should be 1psi here) 5)12.2:1(2-3psi) 6) 11.9:1(3psi+)

1)+8* 2)+8* 3)+8* 4)+4* 5)+1* 6) 0*

I wouldn't let the AFR get any richer than 12.2-12.0 while spooling on the foot brake up to 3-4psi. Then bring it down to 11.6-11.7 as boost gets higher than 3-4psi.

What this table allows you to do is add timing to your main timing table while your at these AFR ratios in the RPM range this table has. So at 1800-2400rpm where you're struggling to build boost and at these AFR ratios this is where you would add the timing.

Set your PE to come on at 90kpa no richer than 12.6-12.8 and your BE to come on at 105kpa no richer than 12.3 at 1psi 12.1 at 2psi 12.0 at 3psi and then set it at 11.6 from 4psi to your max boost kpa. Then set your open loop fuel adder table to be no richer than 13.2:1 at 100kpa in your operating temperature range.

If this sounds complicated it's not and I can explain it better over the phone or in person of course.

mike13

iTrader: (27)

Martin great information, I love this stuff because I can go over it time after time as I learn more I can read it again and have a better understanding.\

I can't tell you guys how much I appreciate you sharing your experience and knowledge. This is stuff you can only get from experience and it would take me years to learn on my own.

Sarg

iTrader: (6)

Definitely cool to see others' take on how to get it done. Thanks for sharing! That is typically how I tune cars. I treat them as a NA car till it gets into boost.

Sales@Tick

iTrader: (3)

If it weren't for people like MightyMouse and Nitroused383 taking me under their wing a long time ago I'd be a no body still and that's the truth.

BTW Nitroused pointed something out through text I kinda messed up on. Don't set your PE to come on until a little after barometric KPA since it varies with elevation.

mike13

iTrader: (27)

I'm not sure what that means "after barometric kpa"?

Sales@Tick

iTrader: (3)

At sea level the KPA reading will be higher on a N/A motor than at elevation.

Say you're above sea level as some of our members are you will only see a maximum of 95kpa on a data log at 100% TPS where as a member at sea level may see 100-105kpa on their data log.

I'd set your PE enable at 100kpa and your BE enable at 105-110kpa that way your tune is N/A until 1lb or so. Makes for lighting quick vacuum to boost transition along with the added timing the AFR spark advance table adds(threw everyone a bone there lets see how many can actually make it work)

MillsMotorvation

Thx a lot!!!