boost creep
TECH Fanatic
Joined: Dec 2019
Posts: 1,129
Likes: 478
why would boost creep be "ucontrolled" boost? because your controller doesnt control it? its as inherently build into the system as on a centri. i have driven my turbo car for many years with intentional boost creep i got by limiting wastegate valve travel.
and if you got full boost at 3600 your choking the engine at 7000 for sure. (unless we were talking an electronically contolled variable turbo as on the late model cars where you get flat torque from 2000 on.)
op, if you get 11 psi in first and "creep" up to 14 psi in third, i consider that an ideal situation. think about it. (i had my car set up with about 5 psi of "creep".)
and if you got full boost at 3600 your choking the engine at 7000 for sure. (unless we were talking an electronically contolled variable turbo as on the late model cars where you get flat torque from 2000 on.)
op, if you get 11 psi in first and "creep" up to 14 psi in third, i consider that an ideal situation. think about it. (i had my car set up with about 5 psi of "creep".)
You obviously didn't read my reply. Boost creep isn't built into a centri, boost ramp is. Boost creep would be where you change your pulley 4 times and still can't keep it from climbing to 20 PSI.
And no, I'm not choking the engine at 7 grand either.
Creeping isn't an ideal situation. Using an electronic boost controller to taper boost with RPM? Sure.
Something completely out of your control that happens whether you want it to or not as an ideal situation? Dumb.
7 Second Club
Joined: Jul 2013
Posts: 240
Likes: 408
From: Crossfield, AB
You obviously didn't read my reply. Boost creep isn't built into a centri, boost ramp is. Boost creep would be where you change your pulley 4 times and still can't keep it from climbing to 20 PSI.
And no, I'm not choking the engine at 7 grand either.
Creeping isn't an ideal situation. Using an electronic boost controller to taper boost with RPM? Sure.
Something completely out of your control that happens whether you want it to or not as an ideal situation? Dumb.
It really is odd to not to want full control over boost....for tuning and motor safety.
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
why would boost creep be "ucontrolled" boost? because your controller doesnt control it? its as inherently build into the system as on a centri. i have driven my turbo car for many years with intentional boost creep i got by limiting wastegate valve travel.
and if you got full boost at 3600 your choking the engine at 7000 for sure. (unless we were talking an electronically contolled variable turbo as on the late model cars where you get flat torque from 2000 on.)
op, if you get 11 psi in first and "creep" up to 14 psi in third, i consider that an ideal situation. think about it. (i had my car set up with about 5 psi of "creep".)
and if you got full boost at 3600 your choking the engine at 7000 for sure. (unless we were talking an electronically contolled variable turbo as on the late model cars where you get flat torque from 2000 on.)
op, if you get 11 psi in first and "creep" up to 14 psi in third, i consider that an ideal situation. think about it. (i had my car set up with about 5 psi of "creep".)
Thread Starter
Teching In
Joined: Oct 2016
Posts: 30
Likes: 5
Sounds like you bought any one of 10 different turbo kits that put the gate in the crossover instead of in that passenger side turbo manifold.
You'll always have trouble controlling boost there. You can upgrade to a larger gate, but it won't be as simple as clamping it on.
A larger fitting will need welded onto the piping if you want it to actually make any difference.
You'll always have trouble controlling boost there. You can upgrade to a larger gate, but it won't be as simple as clamping it on.
A larger fitting will need welded onto the piping if you want it to actually make any difference.
TECH Fanatic
Joined: Dec 2019
Posts: 1,129
Likes: 478
Correct. The way my KB racing turbo manifold is designed, there is no good place to put a WG on it. It's a quality piece and I'm glad to to run it but this would be a downfall for it. The problem will be that no matter what I do, I wont be able to vent any exhaust from my driver side bank. I went back to a stiffer spring combo this past weekend (rated at 11.6lbs instead of 8.7lbs) and saw more boost in all 3 gears as someone on here predicted. 12 lbs in first, 14.5 in 2nd and 16.5 in 3rd. I'm actually ok with this result for now. I will re position and install a larger WG in the future to get a more consistent boost number across the board. I'm running the Holley Terminator X and have failsafes set up for just about everything I could think of - overboost, high MAT, fuel pressure, oil pressure, knock, coolant temp etc etc.
Thread Starter
Teching In
Joined: Oct 2016
Posts: 30
Likes: 5
Thanks for the pic! I'll have to look at mine again, In my application (84 Mercury wagon) I had him build a custom low rise manifold for my driver side. I don't remember having that much open area on the pipe to work with nor room for a gate up there but I'll look again...
TECH Fanatic
Joined: Dec 2019
Posts: 1,129
Likes: 478
Thanks for the pic! I'll have to look at mine again, In my application (84 Mercury wagon) I had him build a custom low rise manifold for my driver side. I don't remember having that much open area on the pipe to work with nor room for a gate up there but I'll look again...
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TECH Apprentice
Joined: Nov 2016
Posts: 371
Likes: 18
From: switzerland
i dont understand why you guys dont understand. why would you want to contol the boost level? what you want to control is cylinder pressure to not destory the engine. i have been observing the tendency to look at the boost level as a god given value for decades. its not.
and awesome, i just wonder, if you have your boos full in @3600, what is your exhaust pressure before turbine @7000?
and awesome, i just wonder, if you have your boos full in @3600, what is your exhaust pressure before turbine @7000?
TECH Fanatic
Joined: Dec 2019
Posts: 1,129
Likes: 478
i dont understand why you guys dont understand. why would you want to contol the boost level? what you want to control is cylinder pressure to not destory the engine. i have been observing the tendency to look at the boost level as a god given value for decades. its not.
and awesome, i just wonder, if you have your boos full in @3600, what is your exhaust pressure before turbine @7000?
and awesome, i just wonder, if you have your boos full in @3600, what is your exhaust pressure before turbine @7000?
Why not just let the ignition timing run out of control too? More timing obviously means more power, right?
Lets let is just creep up an extra 3 or 4 degrees on its own up top! Why would you want to control it?
Why not remove the rev limiter and just let it keep going up? More RPM is obviously more power and speed!
Surrendering control of any factor is a fool's game.
If it was oil pressure, water temperature, oil temperature, inlet air temps, rev limit RPM, EGTs, backpressure, AFR, ignition timing, injector pulse width, ignition dwell, spark plug gap, spark plug heat range, crankcase pressure, or literally any other factor, you would at least want to be able to control it, no?
And my backpressure ratio was under 2:1 up top, the engine made 900+ HP and 4-digit torque.
A well planned setup is better than a poorly planned on that you can't properly control.
TECH Fanatic
Joined: Dec 2019
Posts: 1,129
Likes: 478
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
i dont understand why you guys dont understand. why would you want to contol the boost level? what you want to control is cylinder pressure to not destory the engine. i have been observing the tendency to look at the boost level as a god given value for decades. its not.
and awesome, i just wonder, if you have your boos full in @3600, what is your exhaust pressure before turbine @7000?
and awesome, i just wonder, if you have your boos full in @3600, what is your exhaust pressure before turbine @7000?
Both on another planet..
7 Second Club
Joined: Jul 2013
Posts: 240
Likes: 408
From: Crossfield, AB
Several guys on here have posted threads where simply coiled a tube and mounted an eBay transducer on the end to be able to log back pressure and then posted boost vs. BP. It's something I should have done with my rear mount, but with a new larger billet turbo being 260 shipped, I jumped straight to the solution that followed my hunch lol.
7 Second Club
Joined: Jul 2013
Posts: 240
Likes: 408
From: Crossfield, AB
Several guys on here have posted threads where simply coiled a tube and mounted an eBay transducer on the end to be able to log back pressure and then posted boost vs. BP. It's something I should have done with my rear mount, but with a new larger billet turbo being 260 shipped, I jumped straight to the solution that followed my hunch lol.
