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wastegate boost reference line size, too small?

2208 Views 6 Replies 4 Participants Last post by  DefSport
So basically I have an external wastegate with lines from a 3 port mac valve going into it for an EBC. The lines from the mac valve are about 1/4" ID but the hose supplied with the wastegate seemed a good amount smaller, about 11/64th ID. So I had to use a hose connector with a reduction to join the two. Would this sudden reduction right at the end before the pressure makes it into the bottom of the wastegate cause any problems or am I overthinking it? I wonder this because I seem to have a very slight boost control/creep issue that I'm trying to zero out and it seems that something small like this could be causing it... pic is of the lines. Based on OD of said lines it doesnt look so bad but the ID change is alot more noticeable if you were to take them off and look at at the connector and etc.
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While I don't think something like that would cause the issue, the EBC should be doing it's job by managing the pressures based on how settings in the EBC were set. Assuming hoses were routed correctly and there are no leaks in the system, I'd recheck your input values.
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I would either get 1/4" barbs for the wastegate or the smaller 11/64" for the MAC valve. Having those reducers in there just seems like added points of failure that really don't need to be on a wastegate.
Line size is fine, but get rid of couplers as was mentioned.

Why are you controlling on the top port though? I would just control on the bottom port and vent the top like 99% of wastegate installs should be with a 3 port boost control solenoid.
I would either get 1/4" barbs for the wastegate or the smaller 11/64" for the MAC valve. Having those reducers in there just seems like added points of failure that really don't need to be on a wastegate.
yep ive gone ahead and just ordered new barb fittings in order to just avoid the potential headache lol.
Line size is fine, but get rid of couplers as was mentioned.

Why are you controlling on the top port though? I would just control on the bottom port and vent the top like 99% of wastegate installs should be with a 3 port boost control solenoid.
This is how the EBC states to plumb the lines, as well as what everybody else has told me to do when running an EBC and an external wastegate. My understanding is the ebc pressurizes the top port and supports the wg spring in order to raise and control boost above spring pressure. Heard it also helps with spool for it to operate this way
Running a 3 port to both top and bottom ports makes the effective resolution of the boost controller much more narrow.


Here's a pretty clear guide: Boost Control Plumbing – Get it right, save money. | OnPoint Dyno

I'd recommend this, it's most similar to going to top port on an internal wastegate actuator:

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