I tried tweaking a cal to get more boost. Now all I get is 7-9 (usually 7). Stock cal will spike to 13 and steady at 11. Doesn't seem to be in limp mode, and no codes (I did have a coolant sensor circuit code but it went away and the stock cal never pulled the code).
Any tips?
First question: What base cal are you using? The problem sounds familiar to me and it seems that whatever cal you use, it sends pressure right away to your Wastegate Can.
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Look at all of your boost tables. Your minimum boost will be based off of the table with the lowest value. eg. if Boost vs. Speed is set at 7PSI, but the max boost allowed table is at 25PSI you will still get 7PSI.
I'm using a VNT cal that quantum modified for overboost elimination and +20s. Without me tweaking it runs stock boost.
I have modified all of my boost tables to be flat 14psi under all circumstances just for testing and still the same result. Haven't touched fuel or timing, and tried messing around with the boost cutout settings, with no luck. It's almost like it's running in limp mode with no codes and good fuel and timing curves up to the boost it allows.
Do you still have the VNT on there? If so I am all out of ideas, but otherwise I would check the vac lines and WG solenoid. I think that there was a difference between the latter model TI solenoid function in the cal and the earlier ones, so be sure you have it hooked up right.
Yep, still a VNT. Haven't touched the VNT solenoid settings either. Maybe there's an issue there somewhere in the cal when it tries to boost higher?
Did the cal ever work for you? If not try swapping around the boost/vac line going to the solenoid to the currently free port!
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The stock cal works the way it should, so it's something that's happening when I modify it. Either I have a bad sensor that's causing issues, or the circuit board/eprom combination has an issue.
Have you read the chip on the stock computer, or do you have access to a stock cal? If so, open it up as a comparison cal and see what the differences are in the boost related tables.Originally Posted by Whorse
The stock cal has varying boost for all different settings, but I would think that flatlined on all settings would raise the minimum regardless and it won't even do that.
The way I have that cal set you will have a hard time getting above stock. The only table you really need to change is the wastegate duty cycle vs boost since the VNT will acheve more than the requested boost anyway. Keep the curve I have on the left the same but raise the high point slightly and bend the right side of the curve up a little at a time until you reach your goal. I can help you out as well.
P.S. Just incase there is a misunderstanding: I didn't remove or modify the overboost cut out; I modified the wastegate duity cycle vs boost table so the turbo is under control when and after it hits boost goal (which it is not stock), added CE flash on knock (Shellgame's code), and a rev limiter. If you changed the wastegate duity cycle vs boost table so it is "flat" at 14psi you would probably see really low boost like you are posting about.
Last edited by quantum; 08-06-2008 at 09:18 AM.
No fun cars any more :(
Ahhhhhhhh. Will try
Any idea why it has trouble starting when the engine is hot? I've done a few parking lot swaps because I couldn't get it to fire up, just crank over and over.
I would look at the fueling table which has the transition based on temp.
ETA: FuelStartFromCoolantTemp is believe is what it's called.
I tried tinkering with it to make it back to stock and with the +20 setting but still kinda flakey
I never had that issue with the cal and stock injectors so I imagine the rescale on one of the tables is causing it. My guess would be FuelStartingFromEngineTemp1, FuelStartDecayIntoRun, or KeyOnPrimeInjPW.
I'm attaching a .zip that contains a version that doesn't have those three tables rescaled for the +20's (VNTcontrolcompare.bin). It has a .calx and .tbl file for it as well. You can try to run it or you can compare it to the VNTcontrol I made for you and rescale the tables one at a time until you find the one causing the hot no start (probably the better idea, though more time consuming).
No fun cars any more :(
Wow thanks. We have some serious rain here today so I can't test it. I tried messing around with the wg control but no luck so far, but it's fun trying things out with this.
Just a thought...I've had a couple cals and once my stock cal pull a code 35. Thinking that maybe because it's intermittent I might have a sensor issue causing a problem somewhere as well, maybe even putting it into limp mode?
It works! 14psi is surprisingly quicker than 11 and dawes is showing blue all the way so I have room to play. Thanks a bunch. Now to alter timing and fuel....
I'm having some issues with fuel up to 5psi in 2nd and 3rd sometimes. Fuel pump issue or maybe the fueling based on engine temp, not sure. Ideas?
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