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-   -   Boost Creep problem (https://www.clublexus.com/forums/sc-1st-gen-1992-2000/715603-boost-creep-problem.html)

suprakidxx Oct 29, 2013 10:11 PM

Boost Creep problem
 
2jzge na-t with ebay twin scroll and 50mm drift motion WG and a 56mm Holset hx35. Psi is set at 16 but on a long wot pull it climbs to 19. I had a manifold gasket fail die to a bolt being loose so I'm going threw all of the co next ions to check for leaks. I have been told that my choice in manifold and WG are the problem. :( that's a hard pill to swallow. So what can I do to check for my culprit?

stockhatch Oct 30, 2013 05:46 AM

Post pics of your manifold. Does it have a single dump for the wastegate, or two?

stockhatch Oct 30, 2013 09:38 AM

Some of the ebay manifolds have dual wastegate feeds, but where they tie into the manifold body, the holes are constricted. You can cut the dump tubes off, route out the holes, and weld them back on. When you pay less than $200 for a manifold, you have to count on modding it to work.

Vrank Oct 30, 2013 10:07 AM

How do you know where boost is set? Did you put the springs in the gate yourself?

suprakidxx Oct 30, 2013 10:35 PM

the WG
http://store.driftmotion.com/static/i-wg50mmhks.php
and a aem boost controller ran by the aem v2 ems. the boost guage is how i know it creeps and the tuner told me too

as requested here is the manifold
http://i1330.photobucket.com/albums/...ps9ab4167a.jpg
http://i1330.photobucket.com/albums/...ps5d080abb.jpg
http://i1330.photobucket.com/albums/...ps5bbdc544.jpg
http://i1330.photobucket.com/albums/...ps31d04126.jpg

tight fit
http://i1330.photobucket.com/albums/...ps82f1bfb4.jpg
bottom side looking up, close to frame.
http://i1330.photobucket.com/albums/...ps1c272072.jpg
1'' riser and .5''adapter close fit. rubs sometimes
http://i1330.photobucket.com/albums/...psed3a1b56.jpg

stockhatch Oct 31, 2013 07:12 AM

Where the two dump tubes for the waste gate tie at the collector, the holes may be much smaller than the tube would suggest. Many people have cut the dump tubes off to find tiny, obstructed holes. Once they hog them out and weld the tubes back on, they have no more boost creep.

suprakidxx Oct 31, 2013 10:01 PM

this might be part of the problem. this is the pipe that connects to OUT on external WG
http://i1330.photobucket.com/albums/...ps1ee85e6e.jpg

here is the rest of the pipe. this was done because WG is crazy loud
http://i1330.photobucket.com/albums/...psf319118b.jpg

I was afraid of welding the internal WG because i didnt know if i would like the turbo so i done this to close it and if the ebay ever got stuck closed, my failsafe will trigger and ill get the hint and unbolt this.
http://i1330.photobucket.com/albums/...psda47767d.jpg

ill have it off soon engough and take some pictures

stockhatch Nov 1, 2013 05:01 AM

That wg exit could very well be your issue. Too restrictive.

Ali SC3 Nov 5, 2013 03:00 PM

you should not be having boost creep really even with an ebay manifold, tons have ebay manifolds without any boost creep. Its probably a combination of the settings in the software, the internal wastegate bypassed like that probably doesn't keep it 100% closed like it should, and very possibly whatever that silencer is at the end of your dumptube could be too restrictive along with that crush bend towards the middle/front probably pinches it down alot.

The dump tube should feed into a larger exhaust pipe at an angle or you should just open dump it to atmosphere, there should not be a muffler directly on the dump tube it can cause creep.

suprakidxx Nov 7, 2013 04:18 PM

I'll drill a hole threw the plate on the back of the turbo and have a bolt screw down on the internal WG and I have a tial 44mm ready to instal. And I'll have the software checked by the tuner. I'd rather not dump to atmosphere. How can that be silenced?

Vrank Nov 7, 2013 05:40 PM

If the internal wastegate wasn't 100% closed, the boost would come on super lazy and wouldn't creep. If you want it to not go to atmosphere, then return it into the exhaust.

suprakidxx Nov 8, 2013 12:42 AM


Originally Posted by Vrank (Post 8226431)
If the internal wastegate wasn't 100% closed, the boost would come on super lazy and wouldn't creep. If you want it to not go to atmosphere, then return it into the exhaust.

she spools all the time. just in town cruising in 5th it will make 3psi without me even thinking about it.

I'll do that then. return to the downpipe.

suprakidxx Nov 8, 2013 09:21 PM

And here is the new Tial 44mm to replace the ebay 50mm that is very quesionable.

http://i1330.photobucket.com/albums/...ps08b70239.jpg

emoFTW Nov 10, 2013 07:03 AM

I have a a similar setup. eBay twin scroll manifold, 50mm hks rep wastegate, and I'm on a pte 6766. I have no boost creep at all, and pte billet wheels are more prone to boost creep.


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