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-   -   BEGi seperated gas Downpipe, Wastegate opening enough? (https://www.miataturbo.net/prefabbed-turbo-kits-3/begi-seperated-gas-downpipe-wastegate-opening-enough-38493/)

Full_Tilt_Boogie 08-25-2009 02:37 PM

BEGi seperated gas Downpipe, Wastegate opening enough?
 
3 Attachment(s)
So with my wategate actuator rod completely disconnected I am still building quite a bit of boost.
Earlier today I was able to brake boost it to like 8psi :facepalm:
So Corky was telling me how sometimes a spacer is needed on the DP flange because the wastegate is not able to open far enough, but by the looks of it my wategate is able to open pretty far.

Closed:
Attachment 203927

Opened:
Attachment 203928

Better view of it opened:
Attachment 203929

Does that look like is opened enough?

Braineack 08-25-2009 02:40 PM

needs a longer shaft and SS feed, stat.

evank 08-25-2009 02:58 PM

Porting the wastegate helps reduce/eliminate boost creep. A lot!

Full_Tilt_Boogie 08-25-2009 03:24 PM

Im considering just converting it to a dump tube...

JasonC SBB 08-25-2009 03:32 PM

Compared to the FM and BEGI turbo offerings of 8-12 years ago the manifolds and exhausts are so much more efficient that they will make boost with a very open wastegate.

As others said, porting the wastegate hole in the turbine housing will help - and so would a larger hotside a/r lol.

What's the rest of your setup? (Exhaust, cam timing etc)

Full_Tilt_Boogie 08-25-2009 03:48 PM

Its a 99, stock long block, exhaust cam is retarded a tooth (happened when i saw spraying nitrous and i still havent fixed it, haha)
Its a BEGi Shanghai-S kit, non-intercooled. I have a racing beat race mid pipe and racing beat single tip muffler.

JasonC SBB 08-25-2009 06:14 PM

Retarded exhaust cam will give you extra energetic exhaust gas.
Fix that and your 'gate open boost will come down.

Full_Tilt_Boogie 08-26-2009 12:50 PM


Originally Posted by JasonC SBB (Post 446526)
Retarded exhaust cam will give you extra energetic exhaust gas.
Fix that and your 'gate open boost will come down.

I cannot beleive I totally overlooked the implications of the exhaust cam timing until now.
I can imagine that the increased overlap combined with my current pig rich AFR's would probably create a very hot and energetic condition within the exhaust manifold.

Im gonna get on fixing that first

ARTech 08-26-2009 02:43 PM


Originally Posted by JasonC SBB (Post 446455)
Compared to the FM and BEGI turbo offerings of 8-12 years ago the manifolds and exhausts are so much more efficient that they will make boost with a very open wastegate.

:jerkit:

Your exhuast takes the path of least resistance. You're trying to push all your exhaust gas through a quarter sized hole. Some of it is bound to make it through the turbine. An external wg would be better but still not 100% efficient.

tyson87 08-26-2009 03:23 PM

1 Attachment(s)
sdasdasdasd

Full_Tilt_Boogie 08-26-2009 03:42 PM

The spacer helped on your shanghai setup?

tyson87 08-26-2009 04:10 PM

yeah, the flapper door was banging the dp.
the flapper arm would open more with the DP off than it would on.

now i am having a problem like phils first problem where the flapper gets stuck, i need to put a C-clip on it like he did.

JasonC SBB 08-28-2009 05:21 PM


Originally Posted by sprayed (Post 446913)
:jerkit:

Your exhuast takes the path of least resistance. You're trying to push all your exhaust gas through a quarter sized hole. Some of it is bound to make it through the turbine. An external wg would be better but still not 100% efficient.

What are you jerking off about? I agree with your sentences above. But, with a more efficient i/c and a more efficient manifold, it will make more boost with the quarter sized hole you mentioned, uncovered.

I upgraded from an AVO setup to the BEGI separated setup with no other change and found a stronger topend and that the new setup would make 4-5 psi boost with the wastegate disconnected (it used to make 3 psi). Like the OP, the wastegate was free to open.


BTW to the OP, I should have said with an ADVANCED exhaust cam you will get much more energy in the exhaust. You probably have it backwards, your exahust is opening sooner.

Full_Tilt_Boogie 08-28-2009 06:20 PM

Yah, I thought it was retarded but I may be wrong.

I wouldnt have any issue with 4-5 psi when the wastegate is completely opened, but currently with it completely disconnected It keeps on going up until I get detonation.

Im going to see if Corky will send me a spacer like what tyson has, if that doenst work Im converting it to an external dump (as in, the wastegate outlet doenst feed back into the dowpipe, it just dumps), and if that still doenst fix it Ill port the wastegate...


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