Again, bone stock trucks have this problem so the mp has nothing to do with it. I need to hook up a drive pressure gauge to mess with my vane position and maybe this might also help fix the issue. If a guy can get the turbo to spool super fast like can be done with non VNT's, maybe this issue might go away......
The throttle stomp, count to three then go thread.
- Thread starter LBZ
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Again, bone stock trucks have this problem so the mp has nothing to do with it. I need to hook up a drive pressure gauge to mess with my vane position and maybe this might also help fix the issue. If a guy can get the turbo to spool super fast like can be done with non VNT's, maybe this issue might go away......
I was thinking about the VVT thing too. But then I dismissed that right away because they are engineered for fast spool along with the side affect of not needing a wastegate lol. But I really think they do spool up faster than a fixed turbo, even from a roll (as long as you dont brake boost the fixed turbo) It could be just a delay telling the vanes to change, but if you had them closed earlier wouldn't you be running really high boost when it isn't neccessary too.
Like I said though messing wiht the MAF did help, not totally but it was something to start wiht
Like I said though messing wiht the MAF did help, not totally but it was something to start wiht
I honestly think that B0201 holds back a stock truck. When you add an aftermarket intake this problem is further aggrivated.
Ive yet to do alot of vane tuning but I do also agree that the VNT causes some lag and I think it has to do with vane position. However I would have considered my 2001 to be laggy to downshift and go and it was around 450hp and only 6100lbs so maybe there is some TQ management holding us back? MAF adjustment definately helps.
Ive yet to do alot of vane tuning but I do also agree that the VNT causes some lag and I think it has to do with vane position. However I would have considered my 2001 to be laggy to downshift and go and it was around 450hp and only 6100lbs so maybe there is some TQ management holding us back? MAF adjustment definately helps.
I know when Simon was playing with drive pressure he could get his VNT to spool too quick!! I would like to eliminate the turbo as a problem area so we can move on to the next thing.
Thanks for the help with this guys. For 2 years this has been pissing me off so I'm glad finally we are making some progress!!:thumb:
Thanks for the help with this guys. For 2 years this has been pissing me off so I'm glad finally we are making some progress!!:thumb:
I don't disagree but I don't think any tuning done to the MAF alone will make up the 2 second delay. There has to be more to it.
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I've ask before wiht no response.. Would running higher rail pressure in the lower rpms help? Not enough to make it sound like its about to die, but just thinking it could be a cp3 having to try and build enough pressure before she finally goes
I'm sure the turbo is part of the lag, but the MAF gets rid of the lag it takes for the engine to apply full fueling. If you play with tuning, you can probably get the spooling a little quicker, but you will always have a little bit of turbo lag. In the log that I posted a screen shot of, the delay from 100% throttle to full fuel quantity is almost 1/2 second. That is a pretty long delay.
If Ben wants to get some more logs with speed and RPM (both with stock and modified MAF tables), we may be able to see a little better how the truck's response changes.
If Ben wants to get some more logs with speed and RPM (both with stock and modified MAF tables), we may be able to see a little better how the truck's response changes.
my opinion why with out the tuning equations but with lots of turbo experience is you're coming from low rpm and locked converter. Its not a balanced N/A 427, the motor recieves the mashed throttle command, has to spool, kick out the L/U, then down 2 gears. If im not mistaken the allison is hydromatic and would require a drastic rpm change then react to it unless manually operated with the shift lever or tap shifter. just my opinon to the delay.
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Hondarider552 is the first person that comes to mind having a fixed turbo LBZ. Wonder what kind of delay he has
As was discussed with another member here, could someone try something for me?
Take your desired RP and progressively max it out all the way across the board from say 1200rpm/40mm3 up and see what happens.
I have no idea how it is going to run but it was suggested maybe it's waiting for RP to come up before it starts fueling-worth a shot I think!!
Take your desired RP and progressively max it out all the way across the board from say 1200rpm/40mm3 up and see what happens.
I have no idea how it is going to run but it was suggested maybe it's waiting for RP to come up before it starts fueling-worth a shot I think!!
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What about a 4 second delay from 100% throttle to full boost(at idle)(not full fuel) ive learned to live with it becuase everything ive tried has done nothing.
Could be worse guys, now mine does the pause then the turbo begins to spool then thunk and high reving it pops out of gear.
