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Old 03-18-2009, 08:45 AM   #1
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Default boost overshoot going uphill

I'm getting boost overshoot when under high load, i.e. going up a hill. Is there any way to calm that down? I'm thinking removing the bottleneck in my exhaust might help...thoughts?
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Old 03-18-2009, 12:54 PM   #2
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I can't imagine I'm the only person experiencing this. Bueller?
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Old 03-18-2009, 01:14 PM   #3
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this is with Ebc?
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Old 03-18-2009, 01:37 PM   #4
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Yup, EBC.

Basically, I hit rock solid 9-10 psi on a flat road, and a fairly solid 12 psi going uphill, or any other time there is excessive load on the engine.
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Old 03-18-2009, 02:29 PM   #5
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There have been two other threads on this recently. Both determined that the 16G either doesn't like little exhausts and/or low boost pressure.

Your wastegate is probably experiencing too much backpressure from the exhaust to work efficiently.

If the larger exhaust doesn't fully eliminate your issue the wastegate opening is possibly too small to bleed off the exhaust efficiently. It can be ported and a larger flapper installed. Not likely that this will be a problem after you open up your exhaust system.

Someone else said that they had no problem with creep, but they had a lot higher boost setting and probably had other factors in their favor.
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Old 03-18-2009, 02:31 PM   #6
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crush bends ftl
You need to update to the new MS ebc code for closed loop. Do you make less boost going downhill (less load)? It would seem to me that open loop bc is the problem.
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Old 03-18-2009, 02:34 PM   #7
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Where are you getting your wg signal from?
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Old 03-18-2009, 02:39 PM   #8
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No hills here in FL, sorry.
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Old 03-18-2009, 02:45 PM   #9
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Quote:
Originally Posted by m2cupcar View Post
crush bends ftl
You need to update to the new MS ebc code for closed loop. Do you make less boost going downhill (less load)? It would seem to me that open loop bc is the problem.

they come out with it yet?




ive hit a boost cut uphill once, i was in 4th and didnt feel like downshifting. the solution for me raising the boost cut :P
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Old 03-18-2009, 02:47 PM   #10
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No hills here in FL, sorry.
A hill is like a naturally occurring overpass with dirt filling underneath it. I saw one once as a kid.
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Old 03-18-2009, 02:55 PM   #11
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Quote:
Originally Posted by sixshooter View Post
There have been two other threads on this recently. Both determined that the 16G either doesn't like little exhausts and/or low boost pressure.

Your wastegate is probably experiencing too much backpressure from the exhaust to work efficiently.

Someone else said that they had no problem with creep...
Hmm, not sure how I missed the other threads. I'll take a look around.
It's not creep per se, just hitting a higher boost and sticking there.

Quote:
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crush bends ftl
You need to update to the new MS ebc code for closed loop. Do you make less boost going downhill (less load)? It would seem to me that open loop bc is the problem.
Indeed, one crush bend (truthfully, it's a squeeze bend rather than a proper cruch bend ) ruins the party.

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they come out with it yet?
^ I second the question. I'd heard rumblings about MS2 stuff, but nothing for MS1.


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ive hit a boost cut uphill once, i was in 4th and didnt feel like downshifting. the solution for me raising the boost cut :P
This sounds like a plan, once I get a better tune up in that range.

Funny that this didn't happen with my old IC...
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Old 03-18-2009, 03:01 PM   #12
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Where are you getting your wg signal from?
right outside the compressor outlet
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Old 03-18-2009, 03:16 PM   #13
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Originally Posted by Atlanta93LE View Post
...Funny that this didn't happen with my old IC...
It was like having a crush bend on the other side of the turbo
You've disturbed the balance. Raise the boost limit and where will it end?
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Old 03-18-2009, 03:25 PM   #14
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In another recent thread it was discussed that the hot side of the intercooler should never be the source for your wastegate signal or boost gauge lines. Disregard the factory outlet nipple. Use a source between the IC and the throttle body. Much more reliable signal. The hotside will give you strange behaviors.

I'll hunt for the posts.

EDIT: Found one. Pay particular attention to Professor Joe Perez's dissertations as the thread progresses. https://www.miataturbo.net/forum/t32479/

Last edited by sixshooter; 03-18-2009 at 03:40 PM.
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Old 03-18-2009, 03:44 PM   #15
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Quote:
Originally Posted by sixshooter View Post
A hill is like a naturally occurring overpass with dirt filling underneath it. I saw one once as a kid.

You lie!
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Old 03-18-2009, 04:32 PM   #16
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Originally Posted by m2cupcar View Post
You need to update to the new MS ebc code for closed loop.
DO TELL where the new code is for MS1!!!
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Old 03-18-2009, 04:43 PM   #17
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Quote:
Originally Posted by sixshooter View Post
In another recent thread it was discussed that the hot side of the intercooler should never be the source for your wastegate signal or boost gauge lines. Disregard the factory outlet nipple. Use a source between the IC and the throttle body. Much more reliable signal. The hotside will give you strange behaviors.

I'll hunt for the posts.

EDIT: Found one. Pay particular attention to Professor Joe Perez's dissertations as the thread progresses. https://www.miataturbo.net/forum/t32479/
Thanks for the link. I'll read through that one again, although I recall it mostly having to do with boost drop-off.
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Old 03-18-2009, 04:53 PM   #18
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You need to update to the new MS ebc code for closed loop.
WHAT!? They actually fixed it! I am getting so excited, where is this code!?!?!?
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Old 03-18-2009, 06:18 PM   #19
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Whoa - sorry guys - I was just BS'ing. I do have some working closed loop code. Though it's over ten years old... and in my LINK.
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Old 03-19-2009, 07:34 AM   #20
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Quote:
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Whoa - sorry guys - I was just BS'ing. I do have some working closed loop code. Though it's over ten years old... and in my LINK.
ohh your going to die.
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