I tried the bypass mod yesterday and went back to stock today.
I read the complete thread about it on this site and also ventured over to Cruze Talk to get some input. It seemed logical that bypassing a solenoid which bled off boost at the ECU's command would increase power. In all actuality I experienced slower response and decreased power after the mod. The car was noticeably quicker after the bypass mod was reversed.
This got me thinking about the auxillary vacuum system GM put in place on the 1.4T Ecotec. Why would they develop an elaborate, separate vacuum system just to control boost and power delivery? That doesn't seem very cost effective considering they can effectively control boost with the boost control solenoid which is already in place and a necessary component for the production engine.
Also, I recognized the sound the compressor bypass valve (bov) was making after doing the mod. It was reminicant of the sound I heard after "crushing" the factory bov on my old Lancer Evolution. Depressing the hat on the factory metal valve would increase the spring pressure resulting in less acuation. Meaning, it was harder for the valve to open. This bypass mod on the 1.4 Ecotec produced the same result.
The difference is the Sonic valve isn't harder to open because of a stiffer spring, it's due to a weak vacuum source. I believe Chevrolet designed this auxillary vacuum system on our cars to aid in proper function of the bov. The intake manifold does not have a large plenum and isn't enough to actuate the bov on it's own. Increasing plenum volume would shift the powerband where the average consumer would find less desirable. And a weaker bov spring wasn't the answer because it wouldn't hold enough boost pressure to reach production power goals. Hence, the vacuum chamber and control solenoid.
Now, this is only my theory derived from a little automotive knowledge and experience, and my own personal test bed. I do not have any numbers nor data to back up my theory but I can say with complete certainty that this mod decreased performance.
I read the complete thread about it on this site and also ventured over to Cruze Talk to get some input. It seemed logical that bypassing a solenoid which bled off boost at the ECU's command would increase power. In all actuality I experienced slower response and decreased power after the mod. The car was noticeably quicker after the bypass mod was reversed.
This got me thinking about the auxillary vacuum system GM put in place on the 1.4T Ecotec. Why would they develop an elaborate, separate vacuum system just to control boost and power delivery? That doesn't seem very cost effective considering they can effectively control boost with the boost control solenoid which is already in place and a necessary component for the production engine.
Also, I recognized the sound the compressor bypass valve (bov) was making after doing the mod. It was reminicant of the sound I heard after "crushing" the factory bov on my old Lancer Evolution. Depressing the hat on the factory metal valve would increase the spring pressure resulting in less acuation. Meaning, it was harder for the valve to open. This bypass mod on the 1.4 Ecotec produced the same result.
The difference is the Sonic valve isn't harder to open because of a stiffer spring, it's due to a weak vacuum source. I believe Chevrolet designed this auxillary vacuum system on our cars to aid in proper function of the bov. The intake manifold does not have a large plenum and isn't enough to actuate the bov on it's own. Increasing plenum volume would shift the powerband where the average consumer would find less desirable. And a weaker bov spring wasn't the answer because it wouldn't hold enough boost pressure to reach production power goals. Hence, the vacuum chamber and control solenoid.
Now, this is only my theory derived from a little automotive knowledge and experience, and my own personal test bed. I do not have any numbers nor data to back up my theory but I can say with complete certainty that this mod decreased performance.