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the turbo appears very responsive in those logs, must feel nice.
It does feel nice. Pulls very well uphill in 5th. I am going to do a proper 4th gear pull from 2k for your spool data thread if you'll have it once I get my tune a bit better.
Boost creep is actually less noticeable when you run more boost. If EBC is set at 10.5 you would never experience creep.
That is not true. I can speak from experience with this turbo. I was getting 10psi just of the WG pressure and the moment I turned up the boost It would creep that much further. Whats the point of get x psi if you don't reach x till the end of the power band? Why not just port it more so you can reach x earlier and hold it longer?
Ya'll keep trying to act like creep is the same between each setup, but it can't possibly be the case. What might work for some, won't work at all for others. I hardly blended my wastegate port into the turbine housing, but I don't creep, just as an example.
Gate preload, tuning, boost plumbing, and daily conditions, etc... all likely play a larger part than you imagine in dealing with creep.
Ramping up boost past peak torque has been discussed other places on the forum. Long story short, if you aren't bending the rods at peak torque chances are you can keep running up the boost till the intake melts, you likely won't break rods and will just flatten the torque curve out into higher RPMs more.
I dont believe it. I seriously doubt with mild porting a flat boost curve can be held. If it starts at p and ends at z somethings wrong. If it starts at z and ends at y. that sounds more logical.
you can doubt him all you want but if you actually knew how a wg works you'd see that he's right. unless you have a bad actuator, more boost will always decrease creep. at a certain point you overcome it altogether unless your wg is the size of a pinhole
OK I won't run MBC, maybe just have my friend add a 1/8" barb to reference when he adds my IAT bung post IC. That will just make it open a bit later but shouldn't change how it creeps once it's open right?
Maybe I will just set overboost to cut spark at 13psi and give it a go.
Here is a better 4th gear pull, starting to make 1psi at 1850rpm.
That is not true. I can speak from experience with this turbo. I was getting 10psi just of the WG pressure and the moment I turned up the boost It would creep that much further. Whats the point of get x psi if you don't reach x till the end of the power band? Why not just port it more so you can reach x earlier and hold it longer?
Sounds like you are using a MBC and it is muddling your results, or that's my guess because that's not how it works otherwise.
I guess I'm not being clear enough. Without porting the curve will not be linear as it spools up then flat when the wg opens. It will overshoot and then flatten out. Example. Turbo spools up with ebc and will always overshoot until WG opens and then will settle at desired target. By porting you eliminate that overshoot and possible creep at certain psi. Granted if you pumped 20 psi through it that might not be the case.
Notice how on all these logs, the wastegate rated point is clear. You can see mine was a 7psi actuator if you look at the knee point on the boost log.
The turbo spools normally in a exponential fashion, boost forces the actuator to open the wastegate, but it's not enough to divert enough exhaust away from the turbine. So as your increase rpms, the boost also increases in a linear fashion because the exhaust forces are increasing with rpm, but you can only divert so much past through the wastegate around the turbine.
creep and porting have nothing to do with your spool-up characteristics--that's happening when the wastegate is CLOSED.
My EBC doesn't ever overshoot. It has a setting called "gain" that regulates how early and quickly it opens to prevent overshoot. It's the Greddy Profec B.
Please try an experiment for me prior to more porting. Disconnect the wastegate actuator from the flapper arm and see what boost you get at redline. If it truly needs porting it will be in significant boost when the wastegate is wide open (8psi+). Otherwise it just needs a weaker actuator to allow it to open more readily when you reach the target.
Notice how on all these logs, the wastegate rated point is clear. You can see mine was a 7psi actuator if you look at the knee point on the boost log.
The turbo spools normally in a exponential fashion, boost forces the actuator to open the wastegate, but it's not enough to divert enough exhaust away from the turbine. So as your increase rpms, the boost also increases in a linear fashion because the exhaust forces are increasing with rpm, but you can only divert so much past through the wastegate around the turbine.
creep and porting have nothing to do with your spool-up characteristics--that's happening when the wastegate is CLOSED.
You are right creep and porting do not have anything to do with spool up but the WGA does.
Again what I am talking about is the early onset of boost in which you overshoot the target and then taper down. EVEN your second dyno shows this. You overshoot down in the lower rpm then taper down. Where as just off of WGA by itself you slowly increase pressure.
How would porting the turbo not help get rid of that initially overshoot? Yeah you could change EBC to not come on as hard but then you are back to the solenoid acting like a mbc. By porting the wastgate it helps get rid of that
So one of the big issues I am having is I get different psi in 3rd 4th and 5th. 3rd less than target, 4th on target and 5th over target. After porting I can pretty much hit target in every gear. Explain this too me? Churboman
07-13-2015, 01:57 PM
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