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..New setup spiking with external WG spiking to 25psi in 2nd & 3rd gea ... ughhh

Okay my lost problem I had with the car not building enough boost was because the intercooler had a crack on the weld. Got it fixed car holds 20 perfectly but all that strain destroy the turbo. Sent Turbo out to Jusmx... Amazing rebuild and service.

It is an evo 3 turbo rebuilt w. brand new Tial 38mm wg w. 1.5 bar spring. With the setup on it was hitting 20 psi beautifully. Their was a little leak on the nipple on the jpipe to the MBC. I got it welded up, reinstalled, now the car hits 20 psi in first gear, and spikes to 25 psi in 2nd and 3rd. The car obviously dies in power as it hits 25, and it does it around 3500-4k rpm at 25psi.

After 20 it sounds like the engine revving up/ or turbo extra, as soon as it hits 25 i left off the gas immediately. I do not hear the WG opening aswell.. but dont know if a boost leak would cause that much of a spike? No the MBC no matter how much i lower it will not lower the boost down to 15psi... any suggestions? im going to try a new mbc this week, i currently have a forged mbc
 

onesickcrx

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Jun 3, 2007
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Did you try just running a vacuum line without the boost controller to the wastegate? You need to eliminate which part it is or isn't
 

belize1334

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Nov 18, 2003
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Is the external off of the manifold or o2 housing?

If o2, did you enlarge the waste-gate passage? Even with the flapper arm removed the passage is too small to prevent boost creep. Opening the hole from 26mm to about 40mm will remove that bottle neck and stabilize the boost.
 

I have the 34mm passage side on my turbo. Shaved a little bit off, but would that 4mm difference cause that big of a spkike? and should it drop down after it spikes?? The boost does not drop off
 

Run a vacume line to where? and which part of the wastegate? The side or top part???
 

onesickcrx

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Jun 3, 2007
Messages
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Run a vacuum line from intake manifold to lower fitting on your Tial gate. If it still spikes as said above the feed whole in the turbo or feed pipe to wastegate is to small. Another thing that could be wrong is if you have the wrong spring in it color isn't everything with these gate springs. Each size gate uses a different size spring in case you had someone else install it they could have installed the wrong spring ex: 44 spring in your 38 gate . I would use a new silicone vacuum line as well incase there is a whole in your vacuum line you are using now.
 

vtecds1

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Jan 16, 2004
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Not sure if the same situation...but mine would spike because I had the lines hooked up wrong.
 

belize1334

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Nov 18, 2003
Messages
3,316
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Bozeman, MT
Quoting 2DAMAX:
I have the 34mm passage side on my turbo. Shaved a little bit off, but would that 4mm difference cause that big of a spkike? and should it drop down after it spikes?? The boost does not drop off



First off, is it a genuine mitsubishi housing or an ebay housing? The ebay housings have the larger 34mm flapper but the actually passage is significantly smaller than the regular 28mm style.

Regardless, when using an external wg on the o2 housing you want to enlarge the wg passage SIGNIFICANTLY to remove that bottleneck so that the tial 38mm is the narrowest point in the system.
 

3rdstrikedsm

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Feb 17, 2008
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32159, FL
Just tune for it that is still low boost and fwiw I have run 30+ on a 16g on pump 93 gas so if you have the fuel take the blessing. /ubbthreads/images/graemlins/smile.gif
 

Thanks guys, Belieze this is the upgraded one from Buschur that did the send out awhile back.

Silly me, ran the vacume from the jpipe to the wastegate and its holding 15psi. So I guess MBC it is, Hallman is good, any other brands you suggest?
 

vtecds1

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Jan 16, 2004
Messages
1,705
Location
Las Begas
I`m running a Profec B-Spec 2. A little pricey but I can change the settings in the cockpit.
 

belize1334

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Nov 18, 2003
Messages
3,316
Location
Bozeman, MT
For electronic I like the HKS EVC series. I've heard good things about Blitz too. For manual I think that Lower Shores is the best. Mine worked well and others have also had good experience with them.
 

Quoting 3rdstrikedsm:
Just tune for it that is still low boost and fwiw I have run 30+ on a 16g on pump 93 gas so if you have the fuel take the blessing. /ubbthreads/images/graemlins/smile.gif



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