I just installed a detroit tuned bypass valve on my 03 MCS, however after I removed the old bypass valve and compaired the stiffness to the detroit tuned bypass valve the difference in pressure to open the butterfly was extremely similar.

The reason I ask is the prior owner from 03-05 also installed a Hsport rear sway, so I am curious if he also installed a DT bypass valve at the time.

The old buttefly was set with 0 gap just like the DT unit, and I did not notice a massive difference, maybe a touch more responsive but I had to try hard to feel the difference, I had also never experienced yoyo, but the old (oem?) unit had only one adjustment screw, not two like the DT bypass valve I received (newer OEM style)

Thoughts?

 

My DT is a LOT stiffer than the stock one I took off...But keep in mind that the one I replaced was leaking, so the spring could have been bad?

 

Mine wasn't a while lot stiffer than stock, but there was a noticeable difference, but mine is an 05 and the stock ones are supposed to be better than the ones in the precious years.

 

Last Saturday I went back to my stock bypass valve. Comparing the two is extreme. I almost didn't want put the stock one back on because of honmuch stiffer the DT BPV was. You should definitely be able to tell a difference. Contact DT and see what Chad can do for you. By the way, when I added the DT BPV for the first time a few years back, I went up 1 psi. What differences did you notice and maybe that will tell you if maybe you have a defective DT BPV.